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687

Letters .

;,

..

:

.

....

.,.

.

.

:

.

.

‘

!‘

Ruptured Membrane

Pulmonary on CT

Hydatid

Cyst

and Folded

Pulmonary hydatid disease is a serious problem of worldwide importance. It usually has a wide range of radiologic features that must be distinguished from those of other benign or malignant lesions of the lung [1 -4]. Hydatid cysts caused by Echinococcus granulosus, the common etiologic agent, are fluid-filled cavities with an outer layer, the pericyst, and an inner layer, the endocyst

[1 , 2, 4j. Although

most of these lesions

until they rupture,

a

the clinical [2-4].

status

Ruptured graphs, [1 ,

cause

no signs or symptoms

cyst makes the diagnosis

complicated

some

and

the

radiologic

more difficult because appearances

cysts have several well-known of which

are highly

features

are

on chest radio-

suggestive

2, 4]. One of them, the “water-lily

both

changed

but not always sign,” is associated

year-old woman, had been admitted after an automobile accident. In the first two patients, conventional radiographs showed cavities with the typical water-lily sign. In the third patient, the findings on chest radiographs simulated those of an encysted hydropneumothorax.

In all three patients,

CT showed

thin-walled

cavities

probably

partly filled

with air in the left lower lobe. Scans obtained at mediastinal window settings showed detached and regularly arranged membrane layers

in the dependent part of the cysts (Figs. appearance of a folded blanket. In two cyst was confirmed at surgery. Slow endocyst and nearly complete loss of uniform features

layering of the membrane seen in our cases are

established

by conventional

1 and 2). The layers had the cases, the presence of the retraction of the collapsing cystic fluid may explain the

within similar

tomography

the cavities. Thus, to the “membrane

and bronchography

specific with a

the CT sign”

[2].

Nilgun

Maden

Oyar [k-nit Tekin

Orhan

collapsed endocyst floating on top of the remaining fluid in a cavity [1 , 4]. Although CT is a valuable imaging method for visualizing collapsed

-

Hadi Ozer

membranes, we describe a CT feature in three cases that is the counterpart of the water-lily sign seen on chest

Ege University

School of Medicine

Bornova,

lzmir,

Turkey

radiographs.

Two of our patients, a 26-year-old woman and a 1 2-year-old had spontaneous expectoration of salty fluid. The third patient,

boy, a 34-

REFERENCES 1 . Aggarwal

S, Kumar A, Mukhopadhyay S. Berry M. A new radiologic sign of ruptured pulmonary hydatid cyst (letter). MR 1989;152:431-432 2. Beggs I. The radiology of hydatid disease. AiR 1985;145:639-648 3. Lewall DB, McCorkell SJ. Rupture of echinococcal cysts: diagnosis, classification, and dinical implications. AiR 1986;146:391-394 4. Saksouk FA, FahI MH, Riak GK. Computed tomography of pulmonary hydatid disease. J Comput Assist Tomogr 1986;10:226-232

Pneumopyopericardium

After

Penetrating

Chest

Injury Pneumopyopencardium

: Fig. 1.-CT scan shows a huge In left lower lobe with regular layerIng of hydatid endocyst in dependent part of cyst. Note also atelectasis of lungs and a shift of me-

cavfty

dlastinum.

Fig. 2.-CT scan at mediastinal window levels shows regular layering of collapsed hydatid endocyst with small air bubbles captured be-

tween folds of membrane.

is uncommon

[1 -3].

Its causes

include

trauma and perforation of an inflammatory or suppurative focus into the pericardium [1 -3]. Since the introduction of antibiotics, the mcidance of pericardial suppuration has markedly declined [3]. I report a case of delayed pneumopyopencardium complicated by cardiac tamponade that occurred after penetrating chest injury.

A 25-year-old man was stabbed in the chest. Physical examination showed a 2-cm stab wound in the fourth intercostal space just to the left of the sternal

border.

A chest

ties. The wound was sutured,

radiograph

showed

no abnormali-

and the patient was discharged.

Three

688

LETTERS

Fig.

1.-Chest

shows sac.

air-fluid

level

radiograph in pericardial

AJR:158,

subsegment of a population term follow-up of the whole population.

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It is possible

selected population,

to produce

biopsy

March

1992

for biopsy and ignoring longwe now have a highly biased

yield

rates

that

approach

1 0O%.

All that is needed is to restrict biopsy to those patients who have clear-cut signs of breast cancer. It is clear from the work of Swets et al. [2] that “expert readers” produce receiver-operating-characteristic curves for mammography that are essentially identical. That being the case, if these expert readers evaluated the same screened population, the positive predictive values could be different only if each reader chose to operate at a different

point

on

the

curve.

If the

and thus increase the positive weeks

later the patient was admitted to the hospital in critical condition. He had a body temperature of 39.2#{176}C, a thready pulse, and blood pressure of 80/60 mm Hg with a pulsus paradoxus of 20 mm

lignant lesions positives must

rejection

heard at the apex synchronous with the heart beat. ECG showed a sinus tachycardia of 1 00 beats per minute and diffuse elevation of the ST segment. A chest radiograph showed a pericardial air-fluid

prevalence

level (Fig. 1). The diagnosis

was pneumopyopericardium grossly externally.

with cardiac

purulent pericardial fluid was The patient’s postoperative

will be detected. be accompanied

of it as a screening

Another

factor

dium only may occur. Pericardial laceration is usually of no significance unless infection occurs. The resultant purulent pericarditis may not be suspected until cardiac tamponade occurs. Antibiotics alone are inadequate in the treatment of pericardial suppuration. The pen-

positive predictive

with thorough

pericandial

drainage

but subxiphoid is preferred

J Thorac Surg 1948;17:62-71 microbiologic and therapeutic

aspects 1975;59:68-78 3. Klacsmann PG, Bulkley BH, Hutchins GM. The changed spectrum of purulent pencarditis: an 86 year autopsy experience in 200 patients. Am J 1977;63:666-673

4. Demetriades

D, Van der Veen BW. Penetrating over two years in South Africa.

experience 1034-1041

Positive Detected

The article

by Bassett

rates for mammography masses

those detected the clinical

Trauma

1983;23:

design

for Mammographically

et al. [1] clearly

detected

with an examining

shows

with mammography

because

(i.e., the clinician

that

biopsy

predictive

dated

values

is in order.

of a population

to a huge population

determining

the

yield

were smaller

of the tautology operated

than

that follows

on palpable

masses,

It is a

biopsy

yield

value) and make

be a multifaceted

medical

it the

driving

force

decision-making

for what

in fact

task. Myron Moskowitz University of Cincinnati Cincinnati, OH 45267

REFERENCES 1 . Bassett LW, Uu TH, Giuliano AE, Gold RH. The prevalence of in palpable vs impalpable, mammographically detected lesions. 157:21-24 2. Swets JA, Getty DJ, Pickett RM, et al. Enhancing and evaluating accuracy. In: Medical decision-making. Philadelphia: Hanley 1991:9-18

carcinoma AiR 1991; diagnostic & Relfus,

Reply

We thank Dr. Moskowitz his words

of caution

for his insightful

against

practice

extrapolating

to a huge

comments, biopsy

population

yield

particularly rates

from

of asymptomatic

Biopsy

yield

that had surgery

of asymptomatic rates

(positive

recommended for almost any mammographic abnormality, even when the abnormality has characteristically benign features. This bettersafe-than-sorry approach is undoubtedly influenced by many factors, including lack of training and experience, medicolegal concerns, and

failure to obtain follow-up

results of recommended

biopsies.

than

Dr. Moskowitz expresses a legitimate concern that increasing the threshold for what we call abnormal (choosing a different point on

rates or positive

the receiver-operating-characteristic curve) in order to increase the biopsy yield for carcinoma will increase the number of false-negatives.

hand.

of caution

If the

the use of mammography results in excessive numbers of unnecessary biopsies [1]. In some practices in our community, biopsy is

can be equal to those for clinical examination.

by palpation

value is the

examined.

screened women. It was not our intent to do so. Our purpose was to compare results of clinical examination and mammography in one breast surgeon’s practice in order to respond to the allegations that

and the mammographer examined impalpable abnormalities). given that smaller masses can be detected with mammography A word

should

one surgeon’s

Predictive Values Carcinomas

In this study,

injuries of the heart: J

being

to me that it is not only irrational, but probably counterto embrace a single statistical parameter (in this case

pericar-

REFERENCES

Med

predictive

in the population

[1-4].

Paul Mank Baragwanath Hospital Johannesburg, South Africa

1 . Meyer HW. Pneumopyopericardium. 2. Rubin RH, Moellering RC. Clinical, of purulent pencarditis. Am J Med

in falsein true-

true-positive rate of a test is 90%, achieved at a false-positive rate of 1 %, in a screened population of 100,000 women who have 160 cancers, the positive predictive value is 13%. If the number of cancers in that population were 250, the positive predictive value would be 18%. These are approximations of the frequency of breast cancer in women 45 and 55 years old, respectively. It seems productive,

diotomy

reduction reduction

tool.

that can alter the positive

of the disease

Penetrating wounds of the heart usually cause laceration of both pericardium and myocardium [4], although laceration of the pericar-

cardial space can be drained percutaneously,

However, the by a concomitant

positives. Failure to appreciate these basic fundamentals is what led to the enthusiastic adoption of thermography, and the subsequent

Hg and a markedly elevated jugulovenous pressure. Auscultation of the heart revealed diminished heart sounds with a “splashing” sound

tamponade. At thoracotomy, found, which was drained course was uneventful.

is to limit overcalls value, well-established ma-

motivation

predictive

cannot

screened

predictive

be extrapBy value) of a

women.

Does

it follow

that

for

mammograms

of asymptomatic

women,

we

should produce biopsy yield rates that are very low in order to pick up as many cancers as possible? Arguments against such an ag-

AJR:158,

March

LETTERS

1992

gressive approach include the increased anxiety, morbidity, and costs associated with these biopsies and, over time, decreased compliance of referring physicians that may be detrimental

with recommendations to the acceptance

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raphy [2]. A low threshold

for interpreting

for biopsy-effects of screening mammog-

a complete workup of all women except those with obviously malignant abnormalities can greatly reduce the number of women who have excisional biopsy. The workup of women who have abnormalities found during screening includes appropriate additional mammo-

and, in some cases, fine-needle

REFERENCES 1 . Bassett LW, Uu TH, Giuliano AE, Gold RH. The prevalence of carcinoma in palpable vs impalpable, mammographically detected lesions. AJR 1991; 157:21

the results of a two-view

screening examination as abnormal can be maintained without committing to a low excisional biopsy yield for carcinoma. This is because

graphic views, sonography,

689

or core

2. Howard CA

-24 J. Using mammography

for cancer

control:

an unrealized

potential.

1987;37:33-48

3. Tab#{227}r L, Fagerberg G, Duffy SW, Day NE, Gad A, GrOntoft 0. Update of the Swedish Two-County Program of Mammographic Screeningfor Breast Cancer. Radio! Clin North Am (in press) 4. Moskowitz M. Guidelines for screening for breast cancer: is a revision in order? Radio! Clin North Am (in press) 5. Murphy WA, Destouet JM, Monsees BS. Professional quality assurance for mammography

screening

Radiology

programs.

1990;175:319-320

biopsies.

What then is the ideal threshold for recommending biopsies, and what is the appropriate rate ofcarcinomas detected in these biopsies? Experts Cancer

are far from a consensus Detection Demonstration

about these issues. Project, conducted

In the Breast nationwide in

1973-1 978, the proportion of recommended biopsies varied considerably; it was eight times greater in the most aggressive center compared with the least aggressive [2]. Reduction in mortality has been reported in large screening trials that did not use aggressive

biopsy protocols.

For example, one large population-based European screening trial achieved a 31% decrease in mortality in women invited to screening, with a biopsy yield of one cancer in two biopsies in the initial screening and three cancers per four biopsies subsequently

[3]. On the other hand, a more aggressive approach to biopsies might further reduce mortality, and when used in combination screening intervals, might also be successful in reducing

with shorter mortality in

women less than 50 years old-women in whom tumor growth rates are generally more rapid and for whom current screening strategies are not effective [4]. Finally, we concur

ducting

that it would

a large screening

be irrational

program

for radiologists

to embrace

con-

a single statistical

parameter, such as positive predictive value, and make it the driving force for the screening outcome. However, community-based radiologists, who are performing the bulk of mammographic examinations,

may not be able to access statistical practices. pressure

parameters, Nonetheless, to establish

the data necessary

to calculate

all

let alone apply the results meaningfully to their these same radiologists are under increasing a mechanism for auditing the results of the

biopsies they have recommended [5]. These audits may be difficult to complete when biopsies are performed at various locations, sometimes at clinics or hospitals remote from the facility where the screening mammograms were performed. However, mechanisms for obtaining the results of surgical pathologic examinations of specimens from recommended biopsies can usually be worked out so that true-

Mammographic Fat Necrosis A 36-year-old of deep

venous

Appearance

of Coumadin-Induced

obese woman was admitted thrombosis

of the lower

treated initially with hepanin and subsequently warfanin). taneously

with a clinical diagnosis

extremity.

The patient

with Coumadin

Two days later, edema and ecchymosis in the left breast. Physical examination

was

(sodium

developed sponshowed that the

left breast was much larger than the normal-sized right breast. A large ecchymosis involved the entire left breast and extended into the axilla. A 5-cm nonclotted blood-filled blister the areola, and a 5- to 6-cm area of induration the areola. The breast was tender to palpation.

was 24.6 sec (normal,

was present lateral to was noted medial to The prothrombin time

1 1 .5-1 3.5 sec), which was within the thera-

peutic range. A diagnosis of Coumadin-induced skin necrosis was made, and the Coumadin was discontinued. Subsequently, the blister ruptured, and the skin necrosis was treated with Neosporin (E.

Fougera & Co., Melville, NY) dressings. receiving

subcutaneous

hepanin

At discharge,

the patient was

therapy.

Two months later, the patient was referred for mammography because of a palpable mass in the left breast. Physical examination of the breast revealed a large firm mass at 8 o’clock and a large area of skin discoloration at 2 to 3 o’clock associated with several firm palpable nodules. A mammogram showed skin thickening laterally and multiple oil cysts (fat necrosis) both medially and laterally in the left breast (Fig. 1). The oil cysts varied in size from less than 1 cm to

2 cm. The distribution was superficial, corresponding

to the areas of

positive rates for biopsies can be derived. Arriving at valid falsenegative rates is usually more difficult, sometimes impossible. Therefore, for many radiologists, the true-positive rate for biopsies may

provide the most realistic valuefor

their results with results and in the literature. Although far from perfect, this method does provide an opportunity to recognize inappropriate biopsy rates and make provisions for correported

recting

at continuing

deficiencies.

computer

networks

statistical

parameters

education

It is hoped

comparing courses

that

the establishment

of national

and registries for cancer patients will eventually make it possible for all radiologists to access follow-up data on all their patients and will facilitate the computation of all recommended for their individual

practices. W. Bassett Tsung-Han Liu Armando E. Giuliano

Lawrence

Richard H. Gold University

of California,

Los Angeles, School of Medicine Los Angeles, CA 90024-1721

Fig. 1.-A and B, Craniocaudal(A) and oblique (B) mammograms of left breast of a woman treated with Coumadin show skin thickening laterally

and multiple oil cysts, indicating fat necrosis.

690

LETTERS

induration

and skin necrosis

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nation. The right breast Anticoagulant-induced

described

March 1992

AJR:158,

on the initial physical exami-

was normal. necrosis of the breast

has been reported in numerous cases, but the mammographic appearance has been doscnibed in only four patients [1 -3]. This rare complication usually occurs in middle-aged, obese women between the third and fifth days of treatment with the anticoagulant. The prothrombin time is almost always within therapeutic range(1 .5-2.5 times normal control values). Proposed mechanisms include a direct toxic effect causing capillary rupture followed by thrombotic occlusion of the subcutaneous and subdermal veins, which leads to necrosis of the skin and subcutaneous tissues [4]. Surgical debridement with skin grafting is some-

times necessary. required

[4].

If the necrosis

Other

reported

is extensive,

areas

a mastectomy

of involvement

are

may be

the

buttocks

and thighs, areas of abundant

subcutaneous

fat. In patients receiving

anticoagulants,

to distinguish

idiosyncratic

necrosis

it is important

from intraparenchymal

and prognosis

hemorrhage,

of each are different

because

skin

or fat

the treatment

[4].

IA

lB

Karen S. Baker Carol

University

of Kentucky Lexington,

Fig. 1.-Radiographs of two postmortem specImens show anatomy associated wIth postedcold Impression on the esophagus. Cart = cartilage. A, Anteroposterlor view of up-

B. Stelling

Medical Center KY 40536-0084

per esophagus venous plexus lum.

REFERENCES 1 . Hermann G, Schwartz IS, Slater G. Breast mass in a 69-year-old woman. JAMA 1986;255:939-940 2. McCrea ES. Hemorrhage into the breast. J Can Assoc Radio! 1981; 32:62-63

B,

3. Andersson

I, Adler DD, Ljungberg 0. Breast necrosis associated with thromboembolic disorders. Acta Radio! 1987;28:517-521 Kagan RJ, Glassford GH. Coumadin-induced breast necrosis. Am Surg 1981;47:509-510

4.

Lateral

vIew

of

plexus. (ReprInted from [2].)

with

permIssIon

Fig. shows caused

The

Postcncoid

Dr. Dodds,

large-sized

in his superb

swallow

examinations.

article

on swallowing

used

to

confirm the presence of submucosal veins in the esophagus on its ventral aspect, at and just inferior to the posteroinferior margin of the cricoid cartilage (Figs. 1A and 1 B). These veins of the upper esophagus were previously described and demonstrated in great detail by Butler [3], who stated that the ventral pharyngolaryngeal venous plexus lies in the esophageal submucosa and consists of one to five veins lying close to the midline. They are up to 4 mm in diameter and frequently are dilated because of vanicosis. These veins are found in

both sexes at all ages and must be regarded general

direction

of the veins

is longitudinal,

but they

may be

by many cross anastamoses. They are in the esophageal covering the dorsal surface of the cnicoid cartilage and form longitudinal masses on each side of the midline separated of 2-6 mm. Each half of the plexus is 2 cm wide.

and I think that this submucosal

postcricoid impression when barium descends

Some films show streamlining of the barium column as the barium cascades downward over the venous impression (Fig. 1 C). The impression was called postcricoid merely to describe its p0-

sition: just inferior and posterior

wall two

by a gap

venous plexus causes the

by indenting the esophageal lumen, so that and distends the lumen, the mucosa prolapses over the venous indentation and produces a filling defect on the ventral surface of the barium column. This defect or impression is so constant in its position that it does not appear logical that it could be produced solely by prolapse of a mucosal fold without an underlying cause.

to the inferior margin of the cncoid

cartilage.

As stated by Butler [3] and confirmed by others, including Seaman [4] and Clements et al. [5], the impression has no clinical significance. Radiologically, neoplasm [6].

however,

it may

be mistaken

West Vancouver,

as a normal feature.

joined

Fraser

swallow

streamlInIng of barium by postcrlcoid venous

behind the cricoid

[2], Fraser and I reported the results of injection studies

The

2.-Barium

venous

impression.

on the Esophagus

[1], states that no lamina that would impression on the esophagus noted on barium In our article on the postcricoid impression

veins are located

the postcncoid

explain

Impression

with postcdcoid Injected with bar-

for webs

[2] or for a

R. G. Pitman V7S 2R1

B.C., Canada

REFERENCES 1 . Dodds WJ, Stewart El, Logemann JA. Physiology and radiology normal oral and pharyngeal phases of swallowing. AiR

of the 1990;

154:953-963

2. Pitman RG, Fraser GM. The post.cricoid

impression on the oesophagus. C!in Radio! 1965;16:34-39 3. Butler H. The veins of the esophagus. Thorax 1951;6:276-296 4. Seaman WB. Significance of webs in hypopharynx and upper esophagus.

Radiology

1967;89:32-38

5. ClementsJl, Cox GW, Torres

WE, Weens HS. Cerval esophageal websa roentgen-anatomic correlation: observation of the pharyngo-esophagus. AJR 1974;121 :221 -231 6. Friedland GW, Filly R. The postcncoid impression masquerading as an esophageal tumour. Am J Dig Dis 1975;20:287-291

LETTERS

March 1992

AJR:158,

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Reply Dr. Pitman has questioned the opinion expressed by me and my colleagues [1] about the underlying cause of the postcricoid defect. His interest logically follows from the exquisite work he did investigating this area in 1 965 [2]. His work, and that of others, leaves no doubt about the presence of a venous plexus posterior to the cricoid. We question, however, if these small veins are substantial enough to cause the appearance of a 5- to 1 0-mm mass protruding into the lumen during pharyngography. As described in the article by Butler

[3], another hypopharynx plexus

venous plexus occurs on the dorsal aspect of the at the level of the inferior constrictor muscle. This dorsal

is of similar

size,

yet produces

no recognizable

mass

effect

on the barium column. We agree that the postcricoid defect is a common, benign finding that should not be mistaken for a more ominous process. We remain unconvinced, however, about the contribution of the underlying yenous plexus to account for this finding, and in our opinion, as stated

in our article, the main cause is a mucosal plication. Wylie

Medical

J. Dodds

College of Wisconsin Milwaukee, WI 53226

REFERENCES 1 . Dodds WJ, Stewart El, Logemann JA. Physiology and radiology of the normal oral and pharyngeal phases of swallowing. AJR 1990; 154:953-963 2. Pitman RG, Fraser GM. The post-cncoid impression on the oesophagus. C/in Radio! 1965;16:34-39

3. Butler H. The veins of the esophagus.

69i

lymph nodes. Several months before admission, he had been treated prophylactically with aerosolized pentamidine for presumed P. carinii pneumonia. Specimens obtained at autopsy from the visceral organs in which calcifications were found all stained positive for MAI. Special staining showed no evidence of P. carinll. It was presumed that the calcifications were due to disseminated MAI infection. However, further pathologic testing of the tissues with a monoclonal antibody highly specific for P. carinii (Dako clone 3F6) showed widespread evidence of previous P. carinll infection throughout the specimens, even though no histologic evidence of P. carinll was present. Antibody specific for P. carinll antigen was associated with these calcifications. It was assumed that these calcifications were due to P. carinll that had most likely undergone degeneration. MAI also was present in the organs, but not necessarily in regions of calcifications. Both patients presented by Tower et al. had been treated with aerosolized pentamidine. As was stated, dissemination of P. carinll

may be associated with this regimen [2]. It was indicated that special stains for P. carinll were used; however, no mention of antigen testing was made. If antigen testing was done, and the results were negative, then MAI or cytomegalovirus may have been the etiologic agent for the calcifications in these cases. However, if biopsy with special staining alone was used to determine previous infection with P. carinll, organisms may not have been seen, and it may have been falsely

that calcifications

concluded

were due to other etiologic

agents.

Scott St. Amour The Jewish Hospital of St. Louis The Washington University Medical Center St. Louis, MO 63110

Thorax 1951;6:276-296 REFERENCES

Latex

Retention

Balloon

for Barium

Enemas

Anaphylactic reactions to latex retention balloons used for barium enemas are a growing concern. According to my recent experience in Japan, such retention balloons are rarely needed. In 200 barium enemas I performed, a balloon catheter (36-French Foley catheter with silicone balloon) was needed in only two cases. As a former radiology trainee in the United States and now a practicing radiologist

in Japan, I think that retention States. It available catheters the habit

balloons

are

overused

in the

United

may be that some radiologists have only retention catheters in their departments or that some routinely use retention because this is what they learned in their residency. Once of using retention balloons is established, it may be difficult

to do barium enemas without

using the balloons.

these

can be performed

Reply

We thank Dr. St. Amour for his letter drawing

satisfactorily

without

using

devices.

[1] and also to the liver biopsy

agents

and that biopsy

confirmation

Calcifications

Sunnybrook

I read with interest a recent article by Towers

Recently

visceral

an AIDS patient at the Jewish Hospital calcifications

in the

liver,

spleen,

kidneys,

Toronto,

et al. [1] reporting may be (MAI) or

and

abdominal

Health

Science

University Ontario, Canada

Centre

of Toronto M4N 3M5

REFERENCE 1 . Towers

of St. Louis had

J. Towers

Mark

Cynthia E. Withers Paul A. Hamilton and colleagues

in AIDS

that widespread visceral calcifications in AIDS patients caused by infection with Mycobactenium avium-intracellulare cytomegalovirus rather than with Pneumocystis carinii.

of the infectious

is necessary.

Tsukuba Medical Center Hospital Tsukuba-shi, lbaraki 305, Japan

Visceral

to a

specimens from the second patient mentioned in the discussion. The sections and specimens were both negative for P. carinii, whereas control sections were distinctly positive. These results are consistent with our suggestion that visceral calcifications in AIDS may not always

be due to P. carinll Yoichi Kikuchi

our attention

specific monoclonal antibody immunohistochemical technique for demonstration of Pneumocystis carinll (Monoclonal mouse anti-Pneumocystis carinll, M778; Dakopatts A/S, Copenhagen, Denmark). We have obtained and applied this agent to multiple sections of liver and

kidney from the patient we described

The use of latex retention balloon catheters involves added risk, extra cost, and extra discomfort for the patient. I encourage American radiologists to use such catheters less often. I think that they will find

that barium enemas

1 . Towers MJ, Withers CE, Hamilton PA, Kolin A, Walmsley S. Visceral calcification in patients with AIDS may not always be due to Pneumocystis carinll. AJR 1991;156:745-747 2. Telzak EE, Cote RJ, Gold JWM, Campbell SW, Armstrong D. Extrapulmonary Pneumocystis carinii infections. Rev Infect Dis 1990;12:380-386

MJ, Withers CE, Hamilton PA, Kolin A, Waimsley S. Visceral in patients with AIDS may not always be due to Pneumocystis AJR 1991;156:745-747

calcification carinll.

LETTERS

692

Ewing

Sarcoma

Manifested

as Acute

AJR:158,

raphy compared

Abdomen

issues

We were interested to read a a 15-year-old Downloaded from www.ajronline.org by 109.161.206.147 on 11/08/15 from IP address 109.161.206.147. Copyright ARRS. For personal use only; all rights reserved

found

recent

case of the day [1 ] in which

girl who had had chronic groin pain for 2 years was

to have a Ewing

sarcoma

of the superior

pubic

ramus.

A 6-year-old girl recently was admitted to our hospital because she had had pain in the right iliac fossa, anorexia, and vomiting for 24 hr. She had previously been well. She had tenderness with guarding in the right lower quadrant and mild leukocytosis. A diagnosis of acute appendicitis was made, and laparotomy was performed. At surgery, the appendix was normal. However, a large hematoma was observed extending from the pelvis and displacing the bladder to the left. Subsequent plain radiography, radionuclide bone

scanning,

remarkably

and contrast-enhanced to that described

CT scanning showed a lesion by O’Connor et al. [1], but on examination confirmed the diagnosis of

similar

the right side. Histologic Ewing sarcoma. The most common

manifestations

of Ewing sarcoma

are pain and

swelling related to the bone symptoms such as anorexia,

involved. However, systemic signs and intermittent fever, and malaise are not uncommon. Hemorrhage and necrosis, common histologic features of these tumors, may produce local pain, erythema, and increased temperature so that they mimic infection. Approximately 20% of Ewing sarcomas are situated within the bones of the pelvis [2], and it is not surprising that these tumors occasionally mimic an acute abdomen. Chronic abdominal or groin pain is probably the more common manifestation, but acute pain may be an indication and has been reported in a 39-year old woman [3] (i.e., well outside the characteristic age range for these tumors).

W. W. Gibbon

G. M. Roberts University Hospital Cardiff, United

of Wales Kingdom

REFERENCES 1 . O’Connor

JF, Martin 1991;156:1314-1320 2. Dahlin DC, Coventry of 165 cases. J Bone 3. Jasani N, O’Connor

LC, Chen H, et al. Pediatric case of the day. AJR

right-sided

MB, Scanlon PW. Ewing’s sarcoma: a critical analysis Joint Surg (Am] 1961;43-A:185-192 RE, Bouzoukis JK. An unusual diagnosis for acute pain in a 39 year old woman (letter). Am J Emerg Med

groin

1991;9:96-98

Sonography Candidates

vs MR Imaging in Children for Liver Transplantation

Who

Are

the authors’

with MR in their series. Let us examine some specific

their

article.

conclusion

that

Only

21 of their

“randomly

tion. It is not clear if this haphazard approach affected the results, but we consider it essential to obtain the spectral Doppler waveform and determine flow direction in the portal vein of every candidate for liver transplantation if the comparison ofsonographic and MR findings is to be credible. Failure to recognize interruption of the inferior vena

cava, a preduodenal portal vein, or polysplenia on sonograms occur only for want of careful attention. Their MR demonstration

can

of siderotic intrasplenic nodules with no corresponding sonographic findings is noteworthy, but Bisset et al. [1) neglected to mention use of the lesser omental thickness/aortic diameter ratio [3] in sonographic detection of portal hypertension. Although it may be possible to measure the dimensions of the recipient’s native liver more precisely with MR than with sonography, this provides no particular advantage in children. The size match in children is based on body weight, and reduction techniques are used if the donor liver is too large. The size of a partial liver graft depends

on the size of the donor organ and is empirically

determined

transplantation (Tzakis AG, personal communication). Portal veins less than 4 mm in diameter were a particular

for Bisset portal

vessels

et al. An expert

sonographer

should

during difficulty

be able to detect

veins 2 or 3 mm in diameter, although demonstration of the may entail meticulous technique. The admittedly “preliminary”

results of Bisset et al. raise questions about the consistency of the and do not substantiate the authors’ assertion that MR

sonograms

has eclipsed sonography for assessment of the portal vein. Our intent is not to minimize the capabilities of MR; on the contrary, we enthusiastically endorse the potential of MR for evaluating progressive liver disease and suspected portal hypertension in children. However, children whose underlying disease has already been fully evaluated and who have been referred to a liver transplantation center need not then be subjected to a costlier examination (i.e., MR imaging) that may mandate sedation. Sonography is less expensive, rarely requires sedation, generally is quicker, entails little discomfort, and can accomplish the crucial objectives: (1) determination of patency and diameter of the extrahepatic segment of the portal vein; (2)

detection

of unsuspected

abnormalities

patency of the superior thrombosis.

such as hydronephrosis

that

portion of the portal vein or does not show mesentenc

veins in children

MR

Children’s

technique of choice for these children merits

comment. During the past decade, real-time sonography-with its more recent embellishments of spectral and color Doppler imaginghas been the hub for preoperative imaging of these children [2]. It would not be prudent to embrace MR as a replacement for sonography in this key role without thoroughly examining the evidence for recommending

36 patients,

selected, at the discretion of the sonographer’ had Doppler assessment to determine the direction of portal venous flow. By definition, selection at the sonographer’s discretion cannot be a random sales-

define the extrahepatic

by Bisset et al. [1] is a welcome contribution to the sparse literature on MR imaging of children who are candidates However,

1992

may need to be dealt with before transplantation; and (3) detection of an occult malignant neoplasm in the diseased native liver, a finding that places the child on the urgent transplant list. MR is an attractive alternative to angiography [4] if sonography does not satisfactorily

The recent article

for liver transplantation. should be the imaging

from

March

with portal

venous

A’Delbert Bowen Hospital of Pittsburgh Gregory A. Applegate Emanuel Kanal

The Pittsburgh

NMR Institute

University

of Pittsburgh

Pittsburgh,

PA

15213

such a departure.

Any attempt to compare the results of sonography with those of another imaging technique must take into account the immensely important operator dependency of real-time sonography. The information provided by mapping deep abdominal vessels, identttying collateral vessels in portal hypertension, and detecting anomalies is directly related to the sonographer’s proficiency and to the effort expended in the search. Bisset et al. [1] acknowledge that operator error may have contributed to the relatively poor showing of sonog-

REFERENCES 1 . Bisset G III, Strife J, Balistreri

plantation: 2.

value

of

MR

155:351-356 Ledesma-Medina J, Dominguez atnicliver transplantation. Part

imaging. Radio!ogy

WF. Evaluation of children for liver transimaging and sonography. AJR 1990; R, Bowen

A, Young LW, Bron KM. Peril-

I. Standardization ofpreoperative diagnostic

1985;157:335-338

3. Patriquin H, Tessier G, Gnignon A, Boisvert

J. Lesser

omental

thickness

in

LETTERS

March 1992

AJR:158,

normal

children:

baseline

for detection

of portal

hypertension.

AiR

1985;

145:693-696

4.

Spritzer CE, Peic NJ, Lee JN, Evans AJ, Sostman HD, Riederer SJ. Rapid MR imaging of blood flow with a phase-sensitive, limited-flip-angle, gradient-recalled pulse sequence: preliminary experience. Radio!ogy 1990;

Downloaded from www.ajronline.org by 109.161.206.147 on 11/08/15 from IP address 109.161.206.147. Copyright ARRS. For personal use only; all rights reserved

176:255-262

693

Our data were obtained

before the application

of color flow tech-

niques. Certainly, with these advances, vascular anatomy and detection of flow can be determined in even the smallest patients. We still think, on the basis of our data, that global anatomy (liver volume, collateral vessels, portal vein size, etc.) is better visualized with MR imaging. Although we still use sonography as our initial screening examination, we do not consider the workup of the child with endstage liver disease complete without MR imaging.

Reply

George

We thank Dr. Bowen and his colleagues for their interest in our article on end-stage liver disease [1]. We recognize that they have a large experience with pro- and postoperative examination of candidates for liver transplantation. Therefore, their criticisms bear careful consideration. We would like to address several specific issues. First, Bowen et al. question our prudence in embracing MR imaging recent

University

REFERENCES 1 . Bisset

GS III, Strife JL, Balistreri WF. Evaluation of children for liver transplantation: value of MR imaging and sonography. AJR 1990;

as a replacement for sonography. It was not stated, nor was it our intention,

compared

provided

that MR should be substituted for sonography. We simply our data from the two techniques and concluded that MR more useful information for the management of children with

end-stage

liver disease.

currently perform the examinations Bowen et al. ency of real-time

We

article.

self-evident

At Children’s

Hospital

Medical

Center,

both sonography

and MR in such children

provide valuable,

complementary

we

because

information.

focus on the immensely

important operator dependsonography. Certainly, this is emphasized in our did not think it necessary to inundate the reader with this concept. Bowen at al. state that they “consider it essential

to obtain the spectral Doppler waveform and determine flow direction in the portal vein of every candidate for liver transplantation.” It is not clear as to why they believe this. Certainly it is essential to show the size and patency of the portal vein. However, in any patient with endstage liver disease (who is being considered for transplantation), information on of significant neglected to diameter ratio.

the direction of portal clinical value. Bowen

mention

venous flow may or may not be et al. also point out that we

use of the lesser

omental

thickness/aortic

155:351-356

2. Brunelle F, Alagille D, Pariente D, Chaumont

et al. [2] found ratios of greater than 2:1 in who had portal hypertension. In 30% of patients

dures: a comprehensive

The Looking-Down

that

off-axis

perineum,

hypertension.

Ann

View

for Pelvic

MR Imaging

of MR is the ability to do multiplanar Previous reports [1-3] suggest that multiplanar imaging is for diagnosis of pathologic changes in the pelvis, an area

ratio

of portal

decompression.

A significant advantage imaging. desirable

anatomy

predictor

approach to portosystemic

Surg 1974;179:791-798

only 52% of patients with documented portal hypertension, the ratios overlapped those of control subjects, ranging between 1 :1 and 2:1 [2]. Therefore, this poor

P. Etude #{233}chographiquede

‘hypertension portale chez l’enfant. Ann Radio! (Paris) 1981;24: 121-130 3. Ledesma-Medina J, Dominguez R, Bowen A, Young LW, Bron KM. Pediatric liver transplantation. Part I. Standardization of preoperative diagnostic imaging. Radio!ogy 1985;157:335-338 4. Qin Y, Cauteren MV, Osteaux M, Willems G. Determination of liver volume in vivo in rats using MRI. Eur J Radio! 1990;1 1 :191 -1 95 5. Warren WD, Salam AA, Smith RB. The meso-spleno-renal shunt prose-

for which MR imaging is wall suited. Baumgartner

Brunelle

is an extremely

S. Bisset Ill

Janet L. Strife Children’s Hospital Medical Center of Cincinnati, College of Medicine Cincinnati, OH 45229-2899

The

imaging

of the cervix.

additional sagittal,

perspective coronal,

at al. [1] reported showing the zonal We think that the off-axis view provides an

of the pelvis

is helpful

in

of the pelvis not obtained

or transverse

imaging.

and the normal anatomy

It

through

conventional

can be used to show the

and pathologic

changes

(SE 600/25).

A line drawn

in the

detection of intrasplenic siderotic nodules (detected readily by MR and not noted on sonography in our study) is very specific. Bowen et al. state that “an expert sonographer should be able to

detect portal veins 2 or 3 mm in diameter.” However, in their own published series [3], the portal vein was identified in only 68% (26/ 38) of patients before liver transplantation. In this same series, the inferior

vena cava was visualized

in whom the authors performed inadequacy

in only 74% (28/38).

were “not sure,” abdominal

In six children

angiography

was

to define the anatomy [3]. Was this an operator-dependent or lack of meticulous technique? In our population,

whom a diligent search was made to locate sonography, MR imaging was more sensitive.

the portal

in

vein by

Bowen et al. also question the advantages of being able to measure the size of the native liver. As pointed out in our manuscript,

not all

patients had transplantation. Many of these patients were managed medically. Certainly, MR is superior to sonography for measuring liver

volume [4]. This is related to a lack of spatial resolution differentiation

on sonography.

Determination

of hepatic

and tissue volume

can

be used for diagnosis of some diseases and for evaluation of nosponses to therapy [4]. This in vivo estimation of volume also can be used to monitor liver perfusion after portosystemic shunt procedures [5]. In patients with hepatic neoplasms, the volume of the liver can be used as a parameter for estimating tumor growth rate [4]. These represent

several

advantages

that have not been fully explored.

Fig.

1.-Sagittal

localizer

MR image

from

symphysls pubis to sacral promontory forms a 90#{176} angle at pubic symphysis. Diagonal lines show subsequent positions for imaging. Fig. 2.-”Looking down” MR Image of pelvis shows perineum, vagina (1), air in the rectum (2), bulbospongiosus muscle (straight solid arrow), superficial perineal (ColIc) fascIa (open arrows), and vaginal artery branch of internal iliac artery (curved arrow). Deep margin of bulbospongiosus muscle Identifies plane of inferior fascia of urogenItal diaphragm. surgery, a benign fibroma was found deep to urogenital diaphragm.

At

LETTERS

694

female

The resultant

pelvis.

view permits a perspective

AJR:1 58, March

1992

for preoper-

ative planning

before gynecologic surgery such as myomectomy. We have termed this the pelvic “looking down” view. The technologist is instructed to define a line from the superior

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margin of the symphysis projection. pubis

The

angle

between

be approximately

should

for slight differences

projection.

pubis to the sacral promontory formed

line

in the sagittal

and

the

90#{176} (Fig. 1). The angle

in uterine

T2-weighted

this

symphysis

can

be varied

axis or pelvic tilt as seen in the sagittal

spin-echo

images are obtained

by using a 5-

mm slice thickness with a 2.5-mm intenslice gap. This pulse sequence is chosen to maximize contrast between urinary bladder, uterus, ovaries, and other abnormalities that may be present, such asfibroids. The resultant image is displayed in a plane parallel to the short axis of the true pelvis and thus approximately parallel to the vagina and pelvic floor. Depending on the angle of the uterus (anteflexed, neutral, or retroflexed), the pelvic floor is seen from a surgical perspective, with the right adnexa on the observer’s right and the left adnexa on

the observer’s left, as if the observer from above (Fig. 2). Unlike

in the

structures

standard

coronal

the

relationship

dimension

the view is a blend between a traditional

of adjacent

can be appreciated,

transverse

so

view and the true

coronal plane of the pelvis. The vagina, vaginal fornices, region of the urogenital diaphragm, perineum, and pelvic floor musculature are visible. In addition, flow-void phenomenon from patent vessels may permit visualization of the uterine artery and the artery to the vagina

as well as potential fibroids.

The anatomic

feeding position

B

and B, Transvaginal sonograms of urethral leiomyoma. Trans(A) shows a well-defined, hypoechoic, homogeneous mass. Urethra, which is not distinguishable, is located between probe and tumor. On longitudinal image (B), tumor has a more rounded appearance, and Fig. 1.-A verse image

dilated

proximal

urethra

is seen

on left side of mass.

is looking down into the pelvis

plane,

in the anteropostenor

A

vessels

in patients

of the uterine

the mass was located anterior to the urethra. was not invaded, the tumor could be easily

examination, grayish tint. benign

the cut surface appeared

Microscopic urethral lelomyoma.

examination

to be regular, confirmed

permits

1340 Ottignies-Louvain

Allan M. Haggar Henry Ford Hospital Murray

Hospital

A. Howe

Radiology Associates Toledo, OH 43623

REFERENCES

1001-1002

2.

H, Alpers C, Crooks LE, Sheldon PE. Magnetic resonance imaging ofthefemale pelvis: initial experience. AJR 1983;141 :1119-1128 3. Hricak H, Williams RD, Spring DB, et al. Anatomy and pathology of the male pelvis by magnetic resonance imaging. AJR 1983;141 :1101-1110 Hricak

Leiomyoma Transvaginal

of the Urethra: Sonography

Appearance

of

Michel Donnay Clinique St. Pierre Ia Neuve, Belgium

REFERENCE 1 . Ohtani M, Yanagizawa R, Shoji F, Fukutani K, Yokoyama of the male urethra. Eur Uro! 1982;8:372-373

Accessory

1 . Baumgartner BR, Bernardino ME. MR imaging of the cervix: oft-axis space scan to improve visualization of zonal anatomy. AJR 1989;1 53:

diagnosis

Michel Wacquez

apptox-

Detroit, Ml 48202

with a slightly

the

with large uterine

arteries

the urethra On gross

Jean L. Jonion Carl C. Pauls

imation of the position of the broad ligament.

Toledo

Because removed.

Occipital

M. Leiomyoma

Ventricle

The radiologic literature has little information on accessory occipital ventricles. A report by Hon at al. [1] described the results of a detailed investigation of small, separate, radiolucent structures seen at the tip

of the occipital studies

horn of the lateral ventricle

established

that the medial

on CT scans. Histologic

and lateral

walls

of the ventricle

on

Leiomyoma of the urethra in women is a rare condition. To date, only 20 cases have been reported [1 J. In all cases, diagnosis was made only after excision biopsy. We report a case in which the diagnosis was suspected before surgery because of the sonographic appearance. A 54-year-old woman complained of dysuria, which was attributed

to a mass protruding showed a nontender meatus. Voiding thra. Transvaginal

from the urethral meatus. Physical examination mass 1 cm in diameter in the upper lip of the

cystourethrography showed a dilated proximal uresonography showed a 3.6- by 2.0-cm well-defined

homogeneous mass in the region of the urethra, which was not clearly identified. This mass was lobulated on the transverse view and round on the longitudinal view (Fig. 1). Because the sonohypoechoic,

graphic

appearance

ofthe

lesion was similar

with benign prostatic hypertrophy, such as leiomyoma, was suggested

to the findings

in patients

a benign tumor of the urethra, as the diagnosis. During surgery,

Fig. 1.-CT drop-shaped, sory occipital

scan isolated ventricle.

shows tearright acces-

Fig. 2.-CT intraventricular

scan of patient with blood shows left ac-

cessory occipital questered.

ventricle

is se-

AJR:158,

in the occipital

region

may fuse, resulting

in a sequestered

portion

ever, is the situation

of

Downloaded from www.ajronline.org by 109.161.206.147 on 11/08/15 from IP address 109.161.206.147. Copyright ARRS. For personal use only; all rights reserved

was 21 .3% on CT scans,

bilateral, and 29.5% on autopsy specimens. CT scans, the prevalence was 17%. Recognition

of an accessory

cause it could be misinterpreted

occipital

of which

in which the accessory

Hon et al. used the term

Although

the occipital tnicle

is accurate

ventricle

is important

as a focal lesion,

Johannesburg

be-

such as a lacunar Johannesburg

of letters

being submitted must

disclose

or published

financial

elsewhere

associations

with

ventricle of occipital yenE. Tobias

Roger Scott Brenthurst Clinic 2000, South Africa Peter Goldschmidt Hillbrow Hospital 2000, South Africa

REFERENCE

the tip of is that the More confusing, how-

1 . Hori A, Bardosi

A, Tsuboi K, Maki Y. Accessory occipital lobe. J Neurosurg 1984;61 :767-771

Letters are published at the discretion of the Editor and are subject to editing. Letters to the Editor must not be more than two double-spaced, typewritten pages. One or two figures may be included. Abbreviations should not be used. Limit the number of authors to four, or we will list only the first three and add “and colleagues” to the end of the list. See Author Guidelines. Material

cerebral

Milton

ventricle is opposite so the natural assumption

ventricular structure.

is isolated,

and concise.

one third were

In our own series of 450

of the accessory ventricle (Fig. 2). In some instances, the accessory horn,

accessory

lobe, we think that the phrase accessory

infarct or a cysticercosis lesion. The shape of the accessory ventricle vanes from round to oval or even triangular (Fig. 1 ). Intraventnicular hemorrhage is a useful demonstration of the complete separateness

the contralateral occipital accessory ventricle is a

ventricle

a short contralateral ventricle (Fig. 1).

ventricle. The ependymal layer of the separated ventricle atrophies. The process is similar to that which leads to coarctation of the anterior horn of the lateral ventricle, although in this region, true sequestration does not occur. In the study by Hon et aI., the prevalence of this finding

695

LETTERS

March 1992

should

or other

not be duplicated

possible

conflicts

in letters,

and authors

of interest.

Letters concerning a paper published in the AJR will be sent to the authors of the paper for a reply to be published in the same issue. Opinions expressed in the Letters to the Editor do not necessarily reflect the opinions of the Editor.

cerebral ventricle

of the