Diagnosis Of Pulmonary Embolism By 64-Detector MDCT Combined With Doppler Ultrasonography And Indirect CTV Of The Leg: A Different Protocol

Abstract

The aim of our study was to investigate the contribution of CT angiography in cases with a presumptive PTE diagnosis, evaluating lower extremity veins with CT venography and color Doppler ultrasonography (CDU) and the role of these methods at diagnosis of DVT. 46 patients with presumptive diagnosis of PTE which was confirmed with a positive CT angiography (CTA) were included in the study. Lower extremities between the iliac crest and head of femur and the popliteal region were scanned having 17-18 slices from each area, without administring extra contrast medium with a 0.8 mm slice gap. The patients underwent lower extremity CDU on the same day. Four out of 46 patients were shown to have thrombus by CDU while their CTV were normal. Two of them had an appearance of thrombus on CTV while their CDU were normal. When we consider CDU as the gold standard method, the sensitivity of CTV is calculated as 81.8% and the specificity as 91.6%. Kappa value between two modalities was calculated as 0.738 and a consistency of 87% is found. Mean radiation dose was calculated as 2.43 mSv for CTA and 0.457 mSv for CTV. With the imaging technique so-called combined CTA-indirect CTV method, DVT can be determined with moderate sensitivity and high specificity with application of low dose extra radiation.

Keywords

• Pulmonary Thromboembolism, MDCT, pulmonary CT angiography, indirect CT venography, color doppler ultrasonography

Diagnosis Of Pulmonary Embolism By 64-Detector MDCT Combined With Doppler Ultrasonography And Indirect CTV Of The Leg: A Different Protocol

Öz

Pulmoner tromboemboli (PTE) sık görülmekle birlikte tanısındaki gecikme nedeniyle mortalitesi yüksek bir hastalıktır. PTE ve alt ekstremite derin ven trombozu (DVT) aynı patolojik sürecin iki parçası olmakla birlikte PTE’ nin %90 nedenini alt ekstremite DVT oluşturmaktadır. Bu çalışmanın amacı pulmoner BT anjiografide (BTA) PTE tespit edilen olgularda, alt ekstremite derin venlerinin indirekt BT venografi (BTV) ve RDUS ile değerlendirilmesi ve son iki incelemenin DVT tanısındaki yerini araştırmaktır. Prospektif olarak, Haziran 2009 ve mayıs 2010 tarihleri arasında, ön tanısında PTE olan ve pulmoner BTA’ de PTE tespit edilen 46 hasta çalışmaya dahil edildi. Pulmoner BTA sonrasında indirekt BTV incelemesi ayrı iki bölge (iliak krestler-femur başı arası ve popliteal bölge) alınarak, ek kontrast madde verilmeden yapıldı. Hastalar aynı gün içinde alt ekstremite venlerine yönelik renkli doppler ultrasonografi (RDUS) ile değerlendirildi. Hastaların aldığı radyasyon dozları hesaplandı. Çalışma dahilindeki 22 erkek (ortalama yaş: 48,7) ve 24 kadın (ortalama yaş: 63,4) toplam 46 hastanın tümünde PTE vardı. 46 hastanın 22’ sinde RDUS’ de DVT saptanmış olup 4 hastada RDUS’ de trombüs varken BTV normaldi. 2 hastada da RDUS normal iken BTV’ de trombüs görünümü vardı. RDUS altın standart kabul edildiğinde indirekt BTV’nin duyarlılığı: %81.8 seçiciliği: %91.6 olarak hesaplandı. İki tetkik arasında Kappa değeri: 0.738 olarak hesaplandı ve %87 tutarlılık olduğu saptandı. BTA çekimi için hastanın aldığı ortalama radyasyon dozu 2.43 mSv, indirekt BTV için verilen ek radyasyon dozu ise 0.457 mSv olarak hesaplandı. Kombine BTA-indirekt BTV yöntemi olarak adlandırılan inceleme tekniğinde çok yüksek duyarlılıkta olmasa bile yüksek seçicilik oranında, düşük dozda ek radyasyon verilerek DVT saptanabilmektedir

Anahtar Kelimeler

• Pulmoner tromboembolizm, MDBT, pulmoner BT anjiografi, indirekt BT venografi, renkli dopler ultrasonografi

References

1. Stein PD, Woodard PK, Weg JG, et al. Diagnostic pathways in acute pulmonary embolism: recommendations of the PIOPED II investigators. Radiology 2007; 242:15–21.
2. Yankelevitz DF, Gamsu G, Shah A, et al. Optimization of combined CT pulmonary angiography with lower extrem- ity CT Venography AJR 2000; 174:67–9
3. Kalva SP, Jagannathan JP, Hahn PF, Wicky TS. Venous Thromboembolism: indirect CT Venography during CT Pulmonary Angiography—Should the Pelvis Be Imaged? Radiology 2008; 246:605-11.
4. Taffoni MJ, Ravenel JG, Ackerman SJ. Prospective com- parison of indirect CT venography versus venous sonogra- phy in ICU patients. AJR 2005;185:457-62
5. Loud PA, Katz DS, Klippenstein DL, Shah Grossman ZD. Combined CT venography pulmonary angiography in sus- pected thromboembolic disease: diagnostic accuracy for venous evaluation. AJR 2000;174:61–5.
6. Torbicki A, Perrier A, Konstantinides S, et al. Guidelines on diagnosis and management of acute pulmonary embo- lism. Eur Heart J 2000; 21:1301–36.
7. Nazaroğlu H, Ozmen CA, Akay HO, Kilinç I, Bilici A. 64- MDCT pulmonary angiography and CT venography in the di- agnosis of thromboembolic disease. AJR 2009;192:654–61.
8. Gillum RF. Pulmonary embolism in the United States, 1970–1985. Am Heart J 1987; 113:1262–4.

9. Tapson VF. Prophylaxis strategies for patients with acute venous thromboembolism. Am J Manag Care 2001;7:524–34.
10. Rodger M, Wells PS. Diagnosis of pulmonary embolism. Thromb Res 2001;103:225–38.
11. Carson JL, Kelley MA, Duff A, et al. The clinical course of pulmonary embolism. N Engl J Med 1992; 326:1240–5.
12. Miniati M, Prediletto R, Formichi B, et al. Accuracy of clinical assessment in the diagnosis of pulmonary embo- lism. Am J Respir Crit Care Med 1999;159: 864–71.
13. Catheline JM, Turner R, Gaillard JL, Rizk N, Champault G. Thromboembolism in laparoscopic surgery: risk factors and preventive measures. Surg Laparosc Endosc Percutan Tech 1999;9:135-9.
14. Virginia WK Au, Walsh G, Fon G. Computed tomogra- phy pulmonary angiography with pelvic venography in the evaluation of thrombo-embolic disease Australasian Radiology 2001;45:141–5.
15. Stein PD, Hull RD. Multidetector computed tomography for the diagnosis of acute pulmonary embolism. Curr Opin Pulm Med 2007;13:384-8.
16. Prandoni P, Lensing AW, Prins MH, et al. Residual venous thrombosis as a predictive of recurrent venous thrombo- embolism. Ann Intern Med 2002; 137:955–60.
17. Beecham RP, Dorfman GS, Cronan JJ, Spearman MP, Murphy TP, Scola FH. Is bilateral lower extremity compression so- nography useful and cost-effective in the evaluation of suspected pulmonary embolism? AJR 1993; 161:1289-92.
18. Duwe KM, Shiau M, Budorick NE, Austin JHM, Berkmen YM. Evaluation of the lower extremity veins in patients with suspected pulmonary embolism: a retrospective comparison of helical CT venography and sonography. AJR 2000; 175:1525-31.
19. Loud PA, Grossman ZD, Klippenstein DL, Ray CE. Combined CT venography and pulmonary angiography: a new diag- nostic technique for suspected thromboembolic disease. AJR 1998; 170:951-4.
20. Goodman LR, Stein PD, Matta F, et al. CT venography and compression sonography are diagnostically equivalent: data from PIOPED II. AJR 2007; 189:1071–6.
21. Baldt MM, Zontsich T, Stümpflen A, et al. Deep venous thrombosis of the lower extremity: efficacy of spiral CT venography compared with conventional venography in diagnosis. Radiology 1996; 200:423–8.
22. Loud PA, Katz DS, Bruce DA, Klippenstein DL, Grossman ZD. Deep venous thrombosis with suspected pulmonary embolism: detection with combined CT venography and pulmonary angiography. Radiology 2001; 219:498-502.