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197

Letters

Hypersensitivity

Reaction

to Oral bohexol

REFERENCES

Hypersensitivity reactions after administration of intravascular ionic and nonionic contrast media, and even oral and rectal barium sulfate, are well recognized [1 , 2]. We present a case of a previously unreported severe adverse reaction to orally administered nonionic contrast medium. A fit 31 -year-old man with an ileoanal pouch complained of abdominal bloating. He drank 1 00 ml of iohexol (350 mg/mb) (Omnipaque 350, Nycomed AS., Oslo, Norway) for a follow-through study performed to exclude subacute obstruction and late anastomotic dehiscence. Approximately 1 hr later, he collapsed with cramping abdominal pains, vomiting, hypotension (supine blood pressure, 80/50 mm Hg), and a rapid low-volume pulse (1 20 beats/mm). He also cornplained of mild tightness of the throat, but dyspnea did not develop. He was

treated

with

plasma

expanders,

IV antihistamine,

and

previous

sodium

contrast

trizoate

examinations

and meglumine

were

trizoate Although

a barium

enema

and

two

(Gastrografin, Schering AG, the patient had no previous

Berlin, Germany) pouchograms. exposure to iohexol by any route and had no history of allergy, the contrast reaction.

agent seems to be the only precipitating cause of the adverse The mechanism of the reaction remains obscure. Less than

2% of oral iohexol

is absorbed

from normal bowel [3], and, unlike

barium preparations, it contains no additives. Consequently, any hypersensitivity must be to the contrast agent itself, mediated either by receptors in the bowel wall or via the small quantity absorbed into the circulation. In a recent large-scale study [4], IV nonionic contrast media was associated with such a low prevalence (0.04%) of severe

adverse reactions

that radiologists

may tend to forget

that

the

ischaemia. 4. Katayama

Scand J Gastroenterol 1988;23:983-990 H, Yamaguchi K, Kozuka T, Takashima T, Seez P, Matsuura K. Adverse reaction to ionic and nonionic contrast media. Radiology 1990;175:621 -628

Clinical History and Accurate Chest Radiographs

corti-

costeroids, and he recovered completely. No bowel abnormality was shown in the study or subsequently. An uneventful endoscopy of the pouch had been performed 2 hours before the administration of iohexol, but no medication had been given for 18 hr before the follow-through study. The patient had not eaten for 1 2 hr and had drunk only a little water 6 hr earlier. The only

1 . Feczko PJ, Simms SM, Bakirci N. Fatal hypersensitivity reaction during a barium enema. AiR 1989;153:275-276 2. Janower ML. Hypersensitivity reactions after barium studies of the upper and lower gastrointestinal tract. Radiology 1986;161 : 139-1 40 3. Stordahl A. Urinary excretion of enteral iohexol in rats with intestinal

risks

attached to all contrast media still apply, even if the contrast agent is given enterally. However, a risk of severe, and possibly even fatal, adverse reaction exists for even the safest available contrast media. Also, as in our case, this type of idiosyncratic response may occur in patients with no history of allergy and no previous exposure to the contrast medium.

We read with interest

Brian

London

R. Gbover

by

of

Good et al. [1], “Does Knowl-

edge of the Clinical History Affect the Accuracy

of Chest Radiograph

Interpretation?”

knowledge

The

not

results,

history

does

graphs

for the detection

affect

which

suggest

the accurate

that

interpretation

of interstitial

disease,

of clinical

of chest

nodules,

radio-

and pneu-

mothoraces, seem counterintuitive and contrary to the findings of other investigators [2-5]. This, in part, may be related to (1) the study design and (2) the method of analysis. A diagnosis might be missed for at least two reasons: Either the diagnosis never occurred to the radiologist, or a particular condition did occur, but the radiologist failed to detect or interpret findings consistent with it. The study by Good et al., which asked radiologists to rate the likelihood of interstitial disease, nodules, and pneumothoraces, effectively precluded the first possibility. Asking a radiologist to look for a specific finding may be as powerful an influence as

providing

a history that is “non-cuing.”

In other words, having a form

requiring the radiologists to determine the likelihood of a pneumothorex being present or not biases them just as if they were provided with a clinical history of, for example, right-sided pbeuritic chest pain. In

both

cases,

the

radiologist

will

be

directed

to

search

for

a

pneumothorax.

To determine

whether clinical history altered the radiologist’s

inter-

pretation, the authors compared the area under the receiver-operating-charactenstic (ROC) curves generated with and without clinical information. Providing a history may have influenced the diagnosis without altering the shape of the ROC curve. The shape of, and

therefore Jonathan

the article

Interpretation

the area under, an ROC curve is determined

of a detection

M. Thomas

independent

St. Mark’s Hospital EC1V 2PS, England

reasonable diologist

system of the

to discriminate

particular

cutoff

normal point

to presume that providing toward or away from a correct

from

or threshold

a history diagnosis,

by the ability abnormal.

It is

chosen.

It is

would bias the rabut this would not

i 98

LETTERS

alter

the

shape

of or the

area

under

the

ROC

cited by Good et ab. demonstrates [6] found a statistically

Herman

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positive interpretations

in the presence

curve.

The

histonesfor

literature

observation. Doubibet and increase in the rate of true-

this significant

of a suggestive

as compared

ROC curve-does not affect

not permit the conclusion

the accurate

interpretation

that

of chest

clinical

does

history

rad’iographs.

Craig

should

L. Coblentz

Geoff Norman McMaster University Medical Centre Hamilton, Ontario, Canada L8N 3Z5

We permit

LA. Rey. To: Black WC, Dwyer AJ. Knowledge of clinical history and the accuracy of interpretation of chest radiographs (letter). AJR 1990155:1342-1343 2. Gur D, Good B, Cooperstein LA. Reply. To: Miller \WT. value of clinical history (letter). AJR 1990;155:653-654 3. Schreiber MH. The dinical history as a factor in roentgenogram interpretation. JAMA 1963;185:399-401 4. Berbaum KS, Franken EA, Dorfman DD, et al. Tentative diagnoses facilitate

the detection 1986;21

of diverse

lesions

in chest

radiographs.

Invest

Radio!

:532-539

5. Potchen EJ, Gard JW, Lazar P. Lahaie P. Andary M. The effect of clinical history data on chest film interpretation: direction or distraction (abstr). Invest Radiol 1979;14:404 6. Doubilet P, Herman PG. Interpretation of radiographs: effect of clinical history.

AiR

Reply have

noted

particular

abnormalities

,

in previous

responses

(pneumothorax,

tute providing a history. did contain abnormalities addition, the form that (on

which

providing

causing

curve fraction.

As

performance

to

and

of three

interstitial

of cases

three

we

record

findings)

we think

is quite

in the study

investigated.

In

for scoring appeared as a

different

for a particular

the comment

of changing

over have

qualita-

case.

of Coblentz

indexes

at least

(Az);

thresholds

In order

noted

accurate

them,

but

this

to show some

before,

however,

was

of Cobbentz

and

Terms for Medical

I was pleased evaluation results

to see the article

of diagnostic to medical

range

of the

summary

provided

only

ROC

methods

do provide

not

the

case.

Our

study

of Pittsburgh

PA 15261

by Phillips

making.

The

Making

and Scott

and

the

[1

] on practical

application

authors

bated on the clarity of their presentation.

Value of clinical

are

Anything

of these

to be congratu-

that can make the

difficult subject of statistics and decision analysis easier to understand is certainly welcome. I would like to offer several definitions for consideration. Other

articles have referred to the false-positive ratio negative ratio (FNR) as representing (1 -specificity) ity), respectively and

FNR,

as the

[2-4].

Phillips

inverse

and Scott

probabilities

(FPR)

and

false-

and (1-sensitivuse the same terms, FPR

of their

respective

predictive

values.

given

that

the

disease

is absent,

and

perhaps

it would

be

condition

applied.

obtaining

a negative

if sensitivity

If

represents

a positive result, given that the disease is present, should the FPRs and FNRs under these conditions pretest

likelihood

of obtaining

value

(PV+)

disease

represents

in question,

value

(PV-)

given

a negative

the

given

represents

test,

posttest

likelihood

a positive

test,

the likelihood

should

that

the ratios

that

a patient

has

the

and ifthe

negative

predictive

a patient

is free

of disease,

as defined

by Phillips

and

Scott be referred to as posttest ratios? Without such clarification, the receiver-operating-characteristic imaging

systems,

curves,

as well as posttest

of disease

prevalence,

inherent

probabilitiesfor could

decision

be applied National

characteristics

Naval

Bethesda,

of

making,

incorrectly. H. G. Adams Medical Center

MD 80814-5000

the

false-positive

we

do

David Gun Barbara Good A. Cooperstein

WT.

Decision

examinations

decision

To: Miller

Nor-

effect,

Nor-

data

conclusions.

graphs (letter). AJR 1990:155:1342-1343 2. Gur D, Good B, Cooperstein LA. Aeply. history (letter). AJR 1990;155:653-654

of detection

a meaningful

and

its resulting

1 . Gur D, Good B, Cooperstein LA. Reply. To: Black WC, Dwyer AJ. Knowledge of clinical history and the accuracy of interpretation of chest radio-

a function and

do-

tailed information on relative performance of observers at different false-positive fractions. If we had observed in our analyses significant differences between the two reading modes (i.e., with and without history) as a function of the false-positive fraction, we would have discussed

remark

study

be referred to as pretest ratios? Conversely, if the positive predictive

dis-

to the observers

history

with

curve.

worded

last

of our

REFERENCES

without in the shape or area under the receiver-operating-

change we

were

something

significance (ROC)

must

the

provided

disagree

a change

characteristic

was

criticisms

investigated

knew this does not consti-

a number

than

a particular

respectfully on the

other

they

for all cases,

from

Importantly,

we

nodule,

ease) during the study and the observers

purposes

to similar

2], we think that the fact that

[1

We

our carefully

the

merit

Pittsburgh,

result,

As we

despite

scientific

University

the

tively

convinced, the

As we are discussing conditional probabilities, useful to define terms on the basis of the specificity represents the pretest likelihood of

1981;137:1055-1058

our work

any of these cases, and we do not think that the histories been classified as such.

Lawrence

1 . Gur D, Good B, Cooperstein

checklist

are that

Defining

REFERENCES

man

have

man,

with a nonsuggestive history and a concomitant increase in false positives. This corresponds to a shift of the detection threshold, and not to a change in the area under the ROC curve. Other studies [3, 5] also showed an increase in true-positive rates rebated to providing a history suggestive of a change in threshold; whether they resulted in a change in d’ was not described. We think that the manner in which the study was conducted-the fixed rating task, the lack of analytical distinction between positive and negative histories, and the exclusive focus on the area of the

January 1991

AJR:156,

included

and actual clinical histories of the patients whose images were used in the study. The images were selected before the study was run and without any knowledge of the clinical histories of the patients involved. No attempt was made to create positive or negative

REFERENCES 1 . Phillips wc, scott JA. Medical decision making: practical points for practicing radiologists. AJR 1990;154:1149-1155 2. McNeil BJ, Keeler E, Adelstein SJ. Primer on certain elements of medical decision making. N EngI J Med 1975;293:21 1-215 3. Browner ws, Newman TB. Are all significant P values created equal? JAMA 1987;257:2459-2463 4. Metz CE. ROC methodology in radiologic imaging. Invest Radiol 1986;21 :720-733

Note-The opinions and assertions in the preceding letter are views of the author and should not be construed as official policy or views of the Department of Defense or the Department of the Navy.

TABLE

1: Terms

199

LETTERS

AJR:156, January 1991

Used in Medical

Decision

Making

nodular

discovered incidentally 1 year earlier. The and contained small calcifications. Again, blood flow in the lesion was increased. On radionuclide scanning, the lesion showed hyperactivity, indicative of benign adenoma. All laboratory tests for thyroid function were normal. Many benign nodules, whether solitary or in a multinodular goiter, may show hypervascularity, and this finding has no relationship to lesion

Term

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Probability

Reference 1982;143:29 1981138:723 AJA 1982;138:485 Am J C/in Pathol 1 971 55:105 Semin NucI Med 1 978;8:273 Semin NucI Med 1 978;8:283 Radiology 1 981 ;1 41:25 AJA 1982;138:977 Radiology 1 982;1 43:129 N EngI J Med 1975;293:21 1 Radiology 1 981 141:139 Radiology 1 983;1 43:121

of TP/FP

Radiology Radiology

Proportion of TP/FP decisions Sensitivity vs nonspecificity TP/FP fraction TP/FP TP/FP TP/FP TP/FP

percentages rate ratio response

True positive/negatives Note: TP

=

true positive,

FP

=

lesion

had been

was hypoechoic

thyrotoxicosis

or malignancy.

Raul Barreda Jun V. Kaude Michael

Walter University

College

Gainesville,

fal se positive.

of Medicine

FL 32610-0374

REFERENCE

1 . RaIls PW, Mayekawa Graves

Reply

I appreciate the interest and comments of Dr. Adams. Dr. Scott and I have published two articles [1 , 2] on medical decision making, and both times the issue of proper terminology has arisen. Unfortunately, no widely accepted set of definitions of terms has been adopted, and I think that this leads to much confusion. A few years ago I made a list of some of the terms and their sources that are used in analysis of receiver-operating-characteristic curves. Table 1 shows what I found. The list shows that a variety of terms are used to define the same thing. The best solution to this dilemma would be to adopt a set of standardized definitions that are accepted by everyone. Until that time, the terms used by an author should be defined in the paper or book in which they appear.

Warren C. Milford

Phillips,

Jr.

Memorial

Hospital

Milford,

DE 19963

REFERENCES

1 . Phillips WC, Scott JA, Blasczcynski G. Statistics for diagnostic procedures. 1 . How sensitive is “sensitivity”; how specific is “specificity? AJR 1983;140: 1265-1 270

2. Phillips WC, Scott JA. Medical decision making: ticing radiologists. AJR 1990;1 54:1149-1155

Hypervascularity Color-Coded

of Florida,

Fagien

E. Drane

of Nontoxic Goiter Doppler Sonography

practical

points

for prac-

as Shown

disease:

Mucocele

DS, Lee KP, et al. Color-flow

thyroid

inferno.”

Doppler sonography

in

AJR 1988;1 50:781-784

of the Breast

We report two cases manifested as suspicious

of benign clustered

mucocele of the breast that were calcifications. The first patient, a 48-year-old woman, had had a modified left radical mastectomy 10 months earlier for an infiltrating ductal carcinoma with multifocal intraductal disease. A postoperative mammogram of the right breast had shown a cluster of three to four calcifications that were stable when compared with findings on previous examinations. A reevaluation mammograrn obtained 6 months later showed an increase in the number of calcifications (Fig. 1). Stereotactic fine-needle aspiration yielded calcific debris in mucinous material and a few benign epithelial cells. Excisional biopsy showed a rnucocele and fibrocystic changes. The second patient, a 54-year-old woman, had a cluster of calcifications in the left breast that had not been present 1 year earlier. The findings at mammography, fine-needle aspiration, and excisional biopsy were similar to those of the first case. To our knowledge, the mammographic findings of mucocelelike lesions have not been discussed in the radiologic literature. These lesions recently have been described in the surgical-pathologic literature as mucin-filled, dilated ducts and cysts lined by simple flat to cuboidal epithelium with mucin focally dissecting into the surrounding stroma [1 1.Aspiration of either mucinous carcinoma or mucocele may

by

In 1 988, RaIls et al. [1] described hypervascularity in the thyroid gland in Graves disease and suggested that color-coded Doppler sonography might be a primary noninvasive technique for diagnosing thyrotoxicosis. Their data support the finding that many nontoxic nodular goiters, as well as solitary benign nodules, may be hypervascular, but this finding was not emphasized. We recently observed, in two patients, striking increased blood flow in association with nontoxic nodular goiter, and we would like to give this finding more emphasis. The first patient, a 32-year-old woman, had noticed swelling of the right lobe of the thyroid. She had no clinical signs of a toxic state, and laboratory tests for thyroid function were all within normal limits. Color-coded

Doppler

imaging

showed

markedly

increased

blood

flow

in the periphery of a inhomogeneous mass that involved the whole right lobe of the thyroid. Radionuclide scanning showed areas of hyper- and hypoactivity, indicative of thyroid adenoma with central degeneration. The second patient was a 28-year-old woman in whom a 1 .5-cm

Fig. 1.-Breast

mucocele.

A, Initial craniocaudad view of right breast shows a few rounded calcifications (arrowhead). B, Similar view obtained 6 months later shows an Increase In number of calcifications (arrowhead). C, Enlarged close-up view shows calcifications before stereotactic biopsy.

LETTERS

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200

yield mucin with a few epithelial cells. Excisional biopsy is required for differentiation [1]. The mammographic pattern of calcification in the mucoceles in our two cases is quite similar to that of intralobular calcifications. These are described as single, tightly packed clusters of punctate calcifications that often overlap one another [2J. Although this pattern of calcification generally is due to adenosis, lobular carcinoma in situ has no specific rnammographic pattern and may present in a similar manner. Thus, mucocelelike lesions of the breast should be considered in the differential diagnosis of calcifications of the type sometimes associated with lobular carcinoma in situ. Accumulation of a sufficient

number

tion of these

of cases

may

mucocelelike

permit

the

rnarnrnographic

differentia-

lesions. I. Ray

of Texas,

M. D. Anderson

Cancer

Houston,

was researching the meniscal flounce I observed on MR imaging [2]. Those of us who trained after the heyday of arthrography for diagnosis and arthrotorny for treatment of internal derangements of the knee have missed learning the nuances of a now lost art. Felix S. Chew Massachusetts

Center TX 77030

REFERENCES

1 . Rosen

PP. Mucocelelike tumors of the breast. Am J Surg Pathol 1986;10:464-469 2. Martin JE. Atlas of mammography: histologic and mammographic correlations. Baltimore: Williams & Wilkins, 1988:194-1 95

Meniscus

Revisited

In the July 1990 issue of the AJR, Chew [1] describes a phenomenon seen on MR imaging of the knee that he refers to as meniscal flounce : “an undulating, wavy appearance along the free edge” of the meniscus.

This

appearance

has

been

described

in

the

arthro-

scopic literature, but Chew states that “meniscal flounces were radiologically unobservable before the advent of MR irnaging . . . and would not be visible at all at arthrography.” In 1978, I described the appearance of this phenomenon on arthrograms of the knee [2j. It is seen uncommonly, but by no means rarely, during routine arthrographic stress maneuvers. In one of the cases of meniscal buckling that I illustrated, the identical phenomenon was observed in the same meniscus on subsequent surgical arthrotomy. I think the term buckled meniscus more accurately describes this physiologic phenomenon than meniscal flounce does. As Chew points out, the meniscus is attached along its periphery and at its anterior and posterior horns, which may permit the free internal edge to buckle during stress maneuvers applied to the knee. Such external stresses are applied routinely during arthrography and arthroscopy. However, the knee is not stressed during MR imaging. I am uncertain if the phenomenon that Chew illustrates is a buckled meniscus, but, if it is, it must be observed rarely. Ferris M. Hall

Beth Israel Hospital Harvard Medical School Boston,

MA

02215

REFERENCES 1 . Chew FS. Medial meniscal flounce: demonstration knee (letter).

AJR 1990;155:

2. Hall FM. Buckled rneniscus.

199 Radiology

on MR imaging of the

1978;1 26:89-90

Reply

I regret that I overlooked arthrographic demonstration

Dr. Hall’s fascinating of transient meniscal

Hospital

Medical Boston,

School MA

02114

REFERENCES

1 . Hall FM. Buckled meniscus. Radiology 1978;126:89-90 2. Chew FS. Medial meniscal flounce: demonstration on MR imaging of the knee (letter). AJR 1990;155:199

CT of Bilateral

paper [1] on the buckling when I

Cervical

Spondybolysis

Forsberg et al. [1] recently reported a series of 12 patients with cervical spondylolysis. The authors carefully reviewed the plain film, plain tomographic, and CT appearances of this disorder. They presented one CT section showing an example of unilateral disease. My colleagues and I recently saw a patient with bilateral C6 spondylolysis that had most of the features described by Forsberg et al. We present this case as an example of cervical spondylolysis seen as a bilateral lesion on CT. A 29-year-old man was the restrained driver in a high-speed motor vehicle the

Buckled

General

Harvard

Kirk

Daniel S. Schultz Ruth L. Katz Herman I. Libshitz The University

AJR:156, January 1991

accident.

accident,

He was splenic

and

admitted hepatic

to the

hospital

lacerations,

with a scalp

arnnesia

about

laceration,

and

no focal neurologic complaints. His medical history was unremarkable. Specifically, he had no history of previous neck trauma. Physical examination showed abdominal tenderness. The results of serial neurologic examinations were entirely normal. Radiographs of the cervical spine (Fig. 1 A) showed many of the features of cervical spondylolysis described by Forsberg et al.: (1) the ‘cleft-bow-tie” configuration formed by the triangular ventral and dorsal fragments that make up the articular masses, (2) mild anterolisthesis, (3) hypoplastic

pedicles

(hyperplastic

(better

in this

seen

case)

on

oblique

superior

and

views),

inferior

and

(4)

dysplastic

adjacent

articular

Fig. 1.-Bilateral spondylolysis. A, Lateral radiograph shows classic findings

spondylolysis: configuration

cervical of spine of C6

“cleft-bow-tie” of articular

mild anterolisthesis,

masses,

hypoplastic

pedicles, and dysplastic articular pillars. A = anterior fragment, B = posterior fragment. B and C, Axial CT scans through C6 show well-corticated, smoothly marginated spondylolytic clefts (arrowheads) through articular masses, small pedicles with enlarged vertebral foramina, and spina bifida occulta (arrows).

Fig. 1.-Childproof

pillars. The abnormalities were at the C6 level (74%) at which this lesion has been axial CT scans of the C6 vertebra (3-mm tamed by using a bone algorithm showed

level, the most common reported [1]. Unenhanced contiguous sections) obwell-corticated, smoothly marginated spondylolytic defects through the articular masses bilaterally (Figs. 1 B and 1C). Small pedicles with enlarged vertebral foramina also were seen bilaterally (findings more prominent on the left side). Spina bifida occulta was seen also. Incidentally noted

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on

a lurnbosacral

spinal

series

on the left at L5, with findings right at L5. In the

absence

of any

focal

was

a definite

suggestive

spondylolytic

of a similar

neurologic

deficit,

these

medicine-bot-

tIe cap as an esophageal foreign body. A, Spot film from barium esophagogram shows a circular foreign body

in the proximal

thoracic

esophagus.

B and C, Photographs show childproof safety cap with inner plastic lining in place (B) or removed (C).

defect

defect

on the

findings

were

A

considered diagnostic of long-standing spondylolysis. Lateral flexion/ extension radiographs of the cervical spine showed no ligamentous instability. After 1 week of observation for his abdominal injuries, the patient was discharged from the hospital without any additional treatment.

Douglas University

J. Quint

of Michigan

Hospitals

Ann

Ml 48109

Arbor,

B

REFERENCE 1 . Forsberg DA. Martinez 5, Vogler JB Ill, Wiener MD. Cervical spondylolysis: imaging findings in 12 patients. AJR 1990; 154:751-755

Reply

C

and probably is a common practice, our case shows that there is a risk of swallowing the cap. Most medication containers have safety caps with a plastic inner liner that may dislodge from the main part of the cap.

We were interested to read Dr. Quint’s case of bilateral C6 spondylolysis in a 29-year-old man who had been in a motor vehicle accident. The accompanying radiographs show quite well the diagnostic features of cervical spondylolysis. Three of the patients in our series [1 ] had bilateral spondylolytic defects, all at C6. Interestingly, Dr. Quint’s patient also had spondylolysis at L5. We know of a 16year-old woman who has cervical spondylolysis and abnormal posterior elements at L4 and L5 but not pars interarticularis defects [2]. It should be emphasized further that most patients with cervical spondylolysis have normal neurologic examinations. Like Dr. Quint’s patient, they require no treatment. David A. Forsberg Salutario Duke

University

Durham,

Center NC 27710

REFERENCES 1 . Forsberg DA, Martinez S. Vogler JB Ill, Wiener MD. Cervical spondylolysis: imaging findings in 12 patients. AdA 1990;154:751-.755 2. Barnes DA, Borns P. Pizzutillo PD. Cervical spondylolisthesis associated with the multiple nevoid basal cell carcinoma syndrome. Clin Orthop 1982;1 62:26-30

Childproof Esophageal A 71 -year-old of

dysphagia

woman had

of daily

at one time

swallows

all of the

Coarctation of the Abdominal with Malignant Hypertension Mesenteric Circulation Coarctation of the aorta cause a serious disturbance aorta

near

the

Aorta Associated and Collateral

is an abnormal in blood flow.

junction

Center

IL 60612

of the

narrowing sufficient to The common site is the

ligamentum

arteriosum.

How-

ever, 2% of coarctations affect the abdominal aorta [1 ]. Fewer than 150 cases in the abdominal aorta have been reported in the Englishlanguage literature. We encountered a case with an unusual presentation. A 52-yearold man had a blood pressure of 300/1 80 mm Hg and hypertensive encephalopathy. No abdominal bruits were noted, and femoral pulses were not diminished. He did not have claudication or abdominal angina. A flush aortogram (Fig. 1 A) showed bilateral stenosis of the renal arteries and tapering of the aorta to a mild waist just below the renal arteries. The aortic bifurcation was higher than normal at the L2 level, suggesting a congenital anomaly. No significant pressure

came to the emergency

department

ostial occlusion of the celiac and superior mesenteric arteries was present. A meandering mesenteric artery (Fig. 1 B) originating from the infrarenal aorta provided collateral flow to the occluded vessels.

begun

earlier.

medications.

is taking

Medical

Chicago,

gradient

Bottles

abruptly

2 days

because

She

did

not

recall any pertinent antecedent event. A lateral radiograph of the neck showed gas in the proximal part of the thoracic esophagus. An esophagogram (Fig. 1A) showed a circular filling defect in the cervical esophagus that was not apparent on the plain film. Endoscopy was done, and a foreign body was removed-the plastic inner liner from a childproof safety cap for a medicine bottle (Fig. 1 B). After further discussion with the patient, it became apparent that she takes a number

Luke’s

as a Risk for

Cap on Medicine Foreign Body that

Rush-Presbyterian-St.

thoracic

Martinez

Medical

Eric Brandser Claire Smith

She

habitually

collects

in one of the medicine-bottle

medications

at once.

She

tosses

back of her throat and rinses them down with water. Although placing pills in the cap of a medicine bottle

all the

caps the

pills

she

and then pills

to the

is convenient,

The

was

level

measured

of

renin

across

in the

the

left

coarctation;

renal

vein

however,

was

complete

elevated.

Medical

therapy was unsuccessful, and the patient had a right iliac to left renal artery bypass. At the time of surgery, the aorta was not thickened from fibrosis or hardened from atherosclerosis. A biopsy specimen of the intima of the iliac artery showed no pathologic changes. Minimal postoperative improvement in the patient’s blood pressure occurred, but he refused further treatment, and his pressure has remained elevated. Most authors reserve the term coarctation for a congenital anomaly. Acquired diseases that mimic this condition include Takayasu aortitis

and

other

autoimmune

radiation aortitis, fibromuscular the aorta. Abdominal coarctation

diseases,

tuberculosis

of

the

aorta,

dysplasia, and neurofibromatosis is seen most often in childhood

of or

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Fig. 1.-Coarctation hypertension. A and B, Angiograms coarctation (A, asterisk),

of abdominal

aorta

associated

with

malignant

show stenosis of renal arteries and meandering

mesenteric

(A), mild infrarenal artery (B).

early adulthood

and is manifested as renovascular hypertension. Patients with this condition who reach their 40s most commonly have disease affecting the infrarenal part of the aorta, and claudication is the usual manifestation [2]. The average age at presentation is 21 years, with a second peak in the fourth or fifth decade [3]. Involvement of the renal and splanchnic vessels is common. This has been attributed to intimal hyperplasia due to the eddy currents in the narrowed zone [4]. Stenosis of the renal arteries is seen in nearly 85% of patients. The celiac artery, superior mesenteric artery, inferior mesentenc artery, or a combination of these is involved in one quarter of the cases. As in our case, collateral flow via the mesentenc artery occurs when the superior mesenteric or inferior mesenteric arteries are involved. Abdominal coarctation can be classified on the basis of its type (segmental or hypoplastic) and location (suprarenal, interrenal, or infrarenal). The pattern most commonly encountered is interrenal (50%); next, in order, are infrarenal (25%), suprarenal (1 5%), and diffuse (about 1 0%). Ischemia of the viscera is rarely of clinical significance because of the development of extensive colbaterals [1]. Thomas B. Poulton

Barry S. Rose Aultman Canton,

Hospital OH 44710

REFERENCES

1 . DeBakey ME, Garrett HE, Howell JF, Morris GC Jr. Coarctation abdominal aorta with renal arterial stenosis: surgical considerations. Surg

Fig.

1.-A and B, CT scans obtained rectal contrast material show of aorta-bifurcation prosthesis (arrows).

ti’ation of

of the Ann

1967;165:830-843

2. Bergqvist D, Bergentz S. Ekberg M, Jonsson K, Takolander R. Coarctation of the abdominal aorta in elderly patients. Acta Med Scand 1988;223:

of graft

bntrasigmoidab Aorta-Bifurcation Diagnosed on CT

1988;8:

160-1

E. Coarctation

the patient made an uneventful

siderations

in coarctation

NA, Clagett OT, McDonald JR. Pathologic conof

the

aorta.

Proc

Staff

Meet

Mayo

C/in

University

are published

at the discretion

Academic

Medical the

Center

Netherlands

REFERENCE

1 . Thompson thetic-enteric

Letters

of Amsterdam,

1 105 AZ Amsterdam,

1948;23:324-332

of the Editor

Letters to the Editor must not be more than two

recovery.

To our knowledge, the only published example of a paraprostheticenteric fistula involving the sigmoid colon was diagnosed on the basis of a barium enema [1]. Although an intrasigrnoidal aorta-bifurcation prosthesis is probably unique, we have shown that it can easily be demonstrated with CT. Joan J. M. Peters Bernard Verbeeten, Jr. Jan Kromhout

of the abdominal aorta. J Vasc Surg

64

4. Edwards JE, Christensen

Prosthesis

A 74-year-old man was admitted because of septicemia and pneumonia. Five years earlier, a Sauvage-velours prosthesis to replace the aortic bifurcation had been implanted for treatment of an aortic aneurysm with stenoses of both iliac vessels. Two weeks before admission, the patient had hematochezia on one occasion. Blood cultures were positive for Escherichia co/i. An infected prosthesis with enteric fistulation was postulated as the cause of the septicemia, and antibiotics were administered. Abdominal sonography and angiography of the aorta and iliac vessels were normal. A scintigram made with “Tc-HMPAO-labebed leukocytes showed uptake in the left lower quadrant of the abdomen after 4 hr. A CT scan without rectal contrast material showed no abnormalities at the proximal and distal anastomoses of the vascular prosthesis. However, the left iliac limit of the prosthesis appeared to traverse the lumen of the sigmoid colon for about 3.5 cm (Fig. 1 A). A CT scan obtained after rectal administration of contrast material confirmed this finding (Fig. 1 B). At surgery, the prosthesis had eroded the sigmoid colon and had an intraluminal course of 4 cm. The left iliac limit of the prosthesis was replaced by a Dacron prosthesis, and

275-280

3. Cohen JR, Bimbaum

before (A) and after (B) adminisintrasigmoidal course of left limit Arrhowheads indicate right limit

WM, Jackson fistulas:

and are subject

DC, Johnsrude

radiologic

findings.

IS. Aortoenteric

to editing.

typewritten

pages. One or two figures may be included. Abbreviations should not be used. See Author Guidelines, page AS. Material being submitted or published elsewhere should not be duplicated in letters, and authors of letters must disclose financial associations or other possible conflicts of interest. Letters concerning a paper published in the AJA 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. double-spaced,

and parapros-

AJR 1976;127:235-242