0 1992 Elsevier Science Publishers

32

EURRAD

European Journal of Radiology, 15 (1992) 32-36 B.V. All rights reserved. 0720-048X/92/$05.00

00254

Duplex ultrasound diagnosis of symptomatic proximal deep vein thrombosis of lower limbs R. Quintavallaa,

P. Larini b, A. Miselli b, R. Mandrioli b, U. Ugolottib, M. Pini”

C. Pattacini a and

“5”DivisioneMedica e Centro per le Malattie Emostatiche. and b2” Servizio di RadiologiaDiagnostica, Ospedale Regionale, Parma, Italy (Received

12 August 1991; accepted after revision 8 November

Key words: Vein, thrombosis;

Vein, Duplex ultrasound;

Ultrasound

1991)

study, vein

Abstract

Real time ultrasound (US) was used to examine 165 consecutive inpatients with clinically suspected deep vein thrombosis of lower limbs. In order to evaluate accuracy, the results of non-invasive techniques were compared with ascending venography, performed in all patients. Assessment included only femoro-popliteal veins, because of difficulty in visualizing calf vein with US. Diagnosis of thrombosis was based on noncompressibility of the examined veins; pulsed Doppler provided further information by evaluating blood flow. In our series Duplex ultrasound was very accurate in detecting acute thrombosis of the proximal veins, sensitivity being 97 y0 and specificity 98 %. With US it is also possible to detect conditions that mimic deep vein thrombosis, such as muscular rupture, hematoma, popliteal cyst or compressive tumors. In conclusion US is considered a valid alternative to contrast venography in the diagnosis of proximal vein thrombosis of lower limbs.

Introduction

The diagnosis of deep vein thrombosis (DVT) of the lower limbs made on the basis of clinical signs and symptoms is unreliable [ 1,2]. Venography is the accepted reference method for the diagnosis of DVT, but it is an invasive procedure and there are several problems with this technique [3]. During the last decade considerable experience has been achieved with non-invasive methods such as Doppler ultrasonography and venous occlusion plethysmography, impedance and strain-gauge. Both methods are accurate in detecting occluding thrombi in the popliteal or more proximal veins, but they are insensitive to calf vein thrombosis and to proximal nonoccluding thrombi; moreover, the number of false-positive results is not negligible [4-61. Nowadays, evaluation of the deep venous system can also be made by means of “Duplex” ultrasound

Correspondence to: Dr Roberto Quintavalla, 5a Divisione Medica e Centro Emostasi, Ospedale Regionale, Via Gramsci, 14, 43100 Parma, Italy.

(US), which is simultaneous real-time US imaging combined with pulsed gated Doppler technology. Real-time imaging allows direct visualization ofthe major vascular channels whereas Doppler instrumentation gives a representation of blood flow, allowing discrimination between arterial and venous flow. In addition, US is useful in the detection of a Baker cyst or of calf hematoma, which may mimic DVT [7,8]. In this study 165 consecutive inpatients with clinically suspected DVT of the lower limbs were examined by real-time US. In order to evaluate accuracy, the results of non-invasive techniques were compared with ascending venography, performed in all patients. Methods Patients

Between February 1988 and November 1989, 165 consecutive patients with clinically suspected DVT of the lower limbs were examined. There were 74 males and 91 females, aged 15-89 years (mean = 68 years); all were inpatients. On the day of referral, each patient underwent B-mode ultrasonography of the sympto-

33

matic leg and, within a maximum venography.

of 3 h, ascending

Real-time US

“Duplex” assessment was performed by means of a high-resolution real-time scanner (Diasonic 400) equipped with 5 and 7.5 MHz electrically focused lineararray transducers; transducer selection was made regarding patient habitus and thickness of overlying soft tissues. The patient is positioned supine on the examination table, the examined leg being rotated externally 30-45’. Longitudinal image planes were used to evaluate common femoral, superficial femoral, deep femoral and greater saphenous vein patency and blood flow characteristics. Transverse image planes were employed to confirm anatomic relationships and to assess vein compressibility. The distal superficial femoral and popliteal veins were studied with the transducer positioned posteriorly in the popliteal fossa.

Diagnosis of thrombosis was based on noncompressibility of the examined vein. The compressibility of the vein was assessed by simply pressing the vein with the probe while observing changes in the lumen of the vessel on the monitor. A vein was considered fully compressible if no residual lumen was seen (Fig. 1). Noncompressibility of the examined vein was considered as a sign of DVT (Fig. 2). Besides the US results, venous blood flow was assessed by means of pulsed Doppler, analyzing the audible and graphic representation, and evaluating its variations with breathing and Valsalva’s maneuver. Also the presence or absence of a visible clot within the vessel wall was evaluated, but this was not used as a criterion to confirm the diagnosis. Venographl

Ascending venography was performed according to the method of Rabinov and Paulin [ 93, modified by using ankle tourniquets. A non-ionic dye (Iopamiro) was employed. DVT was diagnosed when either a constant intraluminal filling defect or non-filling of a venous segment was confirmed after a second dye injection, were present. The results of US assessment and contrast venography were interpreted independently by two experienced radiologists and then compared. The angiographers were blinded to both the clinical symptoms and interpretation of the US studies. Results

Fig. 1. A compressible

vein

Of the 165 consecutive patients examined in our series, three were excluded from the analysis because venography could not be performed and five because the results of venograms were inadequate for interpretation. Our analysis therefore included 157 patients. Venography

Deep diagnosed mal and 60 patients

venous thrombosis was venographically in 97 patients. There were 77 (79%) proxi20 (21%) distal DVT. The remaining had normal venograms.

Ultrasonography

Fig. 2. A noncompressible

vein.

Analyzing the overall results, including both proximal and calf vein thrombosis, the sensitivity of US examination was 77 %, since in all 20 calf vein thrombosis “Duplex” ultrasound examination gave negative results (Table 1). If we otherwise consider only the 77 patients with proximal DVT, US assessment was positive, as demonstrated by a noncompressibility of the vein, in

34 TABLE 1

Discussion

Accuracy of real time ultrasonography:

Overall results

Venography

+

-

us +

15

1

us -

22

59

Sensitivity = 77% Specificity = 98% PPV = 98% NPV = 13%

PPV, NPV = positive and negative predictive value.

TABLE 2 Accuracy of real time ultrasonography:

Proximal DVT

Venography

+

us +

15

1

us -

2

59

Sensitivity = 97% Specificity = 98% PPV = 98% NPV = 96%

PPV, NPV = positive and negative predictive value.

75 patients, with a sensitivity of 97% (Table 2). Both false-negative results were due to patent deep femoral veins misinterpreted as superficial femoral veins actually occluded by highly echogenic, presumably old, thrombi, mimicking the surrounding soft tissues. Both cases occurred at the beginning of the study. All but one of the 60 patients with DVT on venography had fully compressible veins at the examination with US. The only false-positive result occurred examining a popliteal vein. Consequently the specificity of ultrasonography in our series was 98% (Table 1). Tables 1 and 2 also show the positive and negative predictive values of US examination. The better results were obtained in proximal DVT, with a positive predictive value of 98% and a negative predictive value of 96%. Neither Doppler blood flow investigations nor the presence or absence of intraluminal echogenic bands (considered to represent a thrombus) were able to improve the accuracy of vein compressibility alone for the diagnosis of DVT. In particular, the visualization of an echogenic band within the lumen of the vein was highly sensitive (98%) but not specific (50x), confirming the results of Lensing and co-workers [lo].

Ideally, when a patient is referred to a vascular laboratory or to a radiological department because of pain and/or swelling of the leg, presence or absence of venous thrombosis should be rapidly established in order to start treatment promptly if it is needed and to avoid the risks of unnecessary anticoagulant treatment. In the last years a number of studies have demonstrated that US scan is the non-invasive technique with the highest sensitivity and specificity in detecting proximal DVT of the legs. A recent review, performed on 14 studies [ 111 showed a cumulative sensitivity for proximal vein thrombosis of 96.6% (431/446) and a specificity of 97.5% (4421453). Our study, revealed that real-time B-mode ultrasonography, with compressibility of the examined vein used as the sole criterion, had 97 y0 sensitivity and 98 y0 specificity for proximal DVT. Considering all thrombi, both of the proximal veins and of the calf veins, the method showed a sensitivity of 77%. In our series, other criteria frequently used in the diagnosis of DVT by means of US examination (i.e. intraluminal echogenicity and venous distension during Valsalva’s maneuver) were relatively inaccurate. We therefore agree with Lensing and co-workers in considering only noncompressibility of femoral or popliteal vein as the main proof of intraluminal thrombosis [lo]. The results of our study are similar to those reported by Lensing [lo] in 220 consecutive symptomatic outpatients and confirm accuracy of real-time ultrasonography in diagnosing proximal DVT also in hospitalized patients, who may differ from outpatients in several respects, including the prevalence of DVT, the location of the thrombus and the opportunity to perform a non-invasive test. The results reported with US examination are better than those obtained with other non-invasive tests. Impedance plethysmography (IPG) for instance, the most thoroughly evaluated and probably the best alternative non-invasive test so far employed, shows cumulatively, a sensitivity of 91.0% for proximal vein thrombosis, and a specificity of 91.4% (529/581 and 1509/1651 respectively (Table 3). This means that if IPG is used as the sole diagnostic test for clinically suspected DVT, almost one in ten patients with proximal vein thrombosis will not receive adequate treatment, and approximately one patient out of ten will receive unnecessary anticoagulation. The safety of withholding anticoagulant treatment from patients with negative US results has been recently

35 TABLE 3 Occlusive impedance

plethysmography:

sensitivity and specificity for deep vein thrombosis

Authors, year [Ref.]

Number of patients or limbs

Sensitivity for proximal DVT

Hull, 1976 [12] Hull, 1977 [13] Hull, 1978 [14] Flanigan, 1978 1151 Cooperman, 1979 [ 161 Ramchandani, 1985 [ 171 Dauzat, 1986 [18] Vaccaro, 1987 [19] Comerota, 1988 [20] Prandoni, 1990 [7]

520 174 486 207 98 100 145 252 178 448

124/133 59/60 155/169 52/54

(93%) (98%) (92%)* (96%)

25/40

(63%)

114/125 (91%)**

(DVT) in patients with clinically suspected Sensitivity for total DVT

64/86

(74%)

64/71 17/23 29/64 9ljlOO 96/l 14 69/97 119/139

(90%) (74%) (45%) (91%) (84%) (71%) (86%)

DVT

Specificity

3861397 (97 % ) 108/114 (95%) 305/317 (96%) 103/136 (75%) 72/75 (96%) 30/36 (83%) 37/45 (82%) 108/138 (78%) 66/81 (81%) 2941312 (94%)

* Results obtained with five consecutive tests. ** Computerized impedance plethysmography.

demonstrated by Vaccaro and co-workers [21], who reviewed the charts of 1022 patients with normal US examinations, and found that only five of these untreated patients suffered serious thromboembolic recurrences (0.48 %). Some problems may arise in patients with clinically suspected DVT and a negative US scan, especially if symptoms are restricted to the calf. Some condition mimicking DVT (Baker cyst, muscular hematoma) can usually be detected by US scan but distal vein thrombosis usually cannot, even though in a recent report Rose et al. [ 81 were able to find, for isolated calf thrombi detected by color-flow US, a sensitivity of 80% and a specificity of 100%. The only limitation was the possibility to perform a technically adequate US study. The accuracy of US evaluation in the diagnosis of suspected isolated calf vein thrombosis must, however, be evaluated with further clinical trials; color-flow Doppler can certainly be more accurate in this setting. We conclude that real-time B-mode ultrasonography, using vein compressibility as the unique criterion, has proven to be an objective, simple and highly accurate non-invasive method for the diagnosis of proximal DVT of the lower limbs in hospitalized patients. References 1 Cranley JJ, Canos AJ, Sull WJ. The diagnosis of deep venous thrombosis: fallibility of clinical symptoms and signs. Arch Surg 1976; 111: 34-36. 2 O’Donnel TF Jr, Abbott WM, Athanasoulis CA, Millan VG, Callow AD. Diagnosis of deep venous thrombosis in the outpatient by venography. Surg Gynecol Obstet 1980; 150: 69-74. 3 Redman HC. Deep venous thrombosis: is contrast venography still the diagnostic “gold standard”? Radiology 1988; 168: 217-278.

4 Hull R, Hirsch .I, Carter C, Jay RM, Ockelford PA, Buller HR, Turpie AGG, Powers P, Kinch D, Dodd PE, Gill GJ, Leclerc JR, Gent M. Diagnostic efficacy of impedance plethysmography for clinically suspected deep vein thrombosis: a randomized trial. Ann Intern Med 1985; 102: 21-28. 5 Hull R, Hirsh J, Sackett DL, Taylor DW, Carter CJ, Turpie AGG, Powers P, Gent M. Replacement of venography in suspected venous thrombosis by impedance plethysmography and “‘I-fibrinogen scanning: a less invasive approach. Ann Intern Med 1981; 94: 12-15. 6 Huisman MV, Buller HR, ten Cate JW, Vreeken J. Serial impedance plethysmography for clinically suspected deep vein thrombosis; a randomized trial. N Engl J Med 1986; 314: 823-828. 7 Prandoni P, Lensing AWA. New developments in noninvasive diagnosis of deep vein thrombosis of the lower limbs. Res Clin Lab 1990; 20: 11-17. 8 Rose SC, Zwiebel WJ, Nelson BD, Priest DL, Knighton RA, Brown JW, Lawrence PF, Stults BM, Reading JC, Miller FJ. Symptomatic lower extremity deep venous thrombosis: accuracy, limitations and role of Color Duplex flow imaging in diagnosis. Radiology 1990; 175: 639-644. 9 Rabinov K, Paulin S. Roentgen diagnosis of venous thrombosis in the leg. Arch Surg 1972; 104: 134-144. 10 Lensing AWA, Prandoni P, Brandjes D, Huisman PM, Vigo M, Tomasella G, Krekt J, ten Cate JW, Huisman MV, Bueller HR. Detection of deep-vein thrombosis by real-time B-mode ultrasonography. New Engl J Med 1989; 320: 342-345. 11 White RH, McGahan JP, Daschbach MM, Hartling RP. Diagnosis of deepvein thrombosis using duplex ultrasound. Ann Intern Med 1989; 111: 297-304. 12 Hull R, vanAken WG, Hirsh J, Gallus AS, Hoicka G, Turpie AGG, Walker I, Gent M. Impedance plethysmography using the occlusive cuff technique in the diagnosis of venous thrombosis. Circulation 1976; 53: 696-700. 13 Hull R, Hirsh J, Sackett DL, Powers P, Turpie AGG, Walker I. Combined use of leg scanning and impedance plethysmography in suspected venous thrombosis. An alternative to venography. N Engl J Med 1977; 296: 1497-1500. 14 Hull R, Taylor W, Hirsh J, Sackett DL, Powers P, Turpie AGG, Walker I: Impedance plethysmography: the relationship between venous tilling and sensitivity and specificity for proximal vein thrombosis. Circulation 1978; 58: 898-902.

36 15 Flanigan DP, Goodreau JJ, Burnham SJ, Bergan JJ, Yao JST. Vascular-laboratory diagnosis of clinically suspected acute deepvein thrombosis. Lancet 1978; II: 331-334. 16 Cooperman M, Martin EW, Satiani B, Clark M, Evans WE. Detection of deep venous thrombosis by impedance plethysmography. Am J Surg 1979; 137: 252-254. 17 Ramchandani P, Soulen RL, Fedullo LM, Gaines VD. Deep vein thrombosis: significant limitations of noninvasive tests. Radiology 1985; 156: 47-49. 18 Dauzat MM, Laroche JP, Charras CH et al. Real-time B-mode ultrasonography for better specificity in the noninvasive diagnosis of deep venous thrombosis. J Ultrasound Med 1986; 5: 625-631.

19 Vaccaro P, Van Aman M, Miller S, Fachman J and Smead WL. Shortcomings of physical examination and impedance plethysmography in the diagnosis of lower extremity deep venous thrombosis. Angiology 1987; 3: 232-235. 20 Comerota AJ, Katz ML, Grossi RJ et al. The comparative value of noninvasive testing for diagnosis and surveillance of deep vein thrombosis. J Vast Surg 1988; 7: 40-49. 21 Vaccaro JP, Cronan JJ, Dorfman GS. Outcome analysis of patients with normal compression US examinations. Radiology 1990; 175: 645-649.

Duplex ultrasound diagnosis of symptomatic proximal deep vein thrombosis of lower limbs.

Real time ultrasound (US) was used to examine 165 consecutive inpatients with clinically suspected deep vein thrombosis of lower limbs. In order to ev...
942KB Sizes 0 Downloads 0 Views