Koray AKDAMAR, Mehmer Ruhi ONUR, Çağaty ANDİÇ, Metin ÇUBUK

Assesment of criteria in differentiation of ureteral stones from phleboliths with thin-slice unenhanced computed tomography

Amaç: Bu çalışmanın amacı kontrastsız helikal bilgisayarlı tomografide üreter taşları ile flebolitleri ayırtetmek için daha önce literatürde tanımlanmış olan kriterlerin yeterliliğini değerlendirmektir. Gereç ve Yöntemler: Altı aylık zaman periyodunda taşı olan 31 hastaya ve toplam 80 fleboliti olan 43 hastaya 3 cm uzunluğunda ince kesit (kesit kalınlığı: 2 mm, pitch: 1) olmak üzere kontrastsız helikal BT çekimi yapıldı. Her kalsifikasyonun boyut, şekil, santral lüsensi, yumuşak doku halka işareti, kuyruklu yıldız işareti, densite değerleri ve profil analizi kaydedildi. Bulgular: Flebolitlerin 52'si (%65) yuvarlak, 28'i oval (%35) şekilliydi. Taşların ise 10'u (%32) yuvarlak, 8'i (%26) oval şekilliydi. Taşların 13'ü (%42) geometrik şekilli iken hiçbir flebolit geometrik şekilli değildi. Flebolit ve taşların ortalama densite değerleri sırasıyla 386,5 HU (131 HU/935 HU) ve 1088 HU (526 HU - 1594 HU) ölçülmüş olup bu değerler arasındaki fark istatistiksel olarak anlamlı idi (p

Üreter taşları ile flebolitlerin ince kesit kontrastsız bilgisayarlı tomografi ile ayırtedilmesinde kullanılan kriterlerin değerlendirilmesi

Objective: The purpose of this study was to asses the accuracy of criteria in distinguishing distal urinary stones from phleboliths defined in the literature with thin-slice unenhanced helical computed tomography (CT). Materials and Methods: Between October 2004 and April 2005, we performed 3 cm length thin-slice (2 mm section thickness, pitch:1) helical CT on 31 patients with urinary stones and on 43 patients with 80 phleboliths. The size, shape, central lucency, soft tissue rim sign, comet-tail sign, density values and profile analysis of each calcification were recorded. Results: Fifty two (65%) of 80 phleboliths were round and 28 (35%) were oval shape. On the contrary, ten (32%) of 31 stone were round, 8 (26%) of them were of oval shape. Geometric configuration was seen in thirteen (42%) stones but not in any phleboliths. Mean densities of phleboliths and stones were 386,5 HU (131 HU/935 HU) and 1088 HU (526 - 1594), respectively. This difference was statistically significant (p<0,05). Eighteen (23%) of 80 phleboliths had central lucency and bifid peak on profile analysis. All 31 stones had a single peak at profile analysis. Although comet-tail sign was seen at 12 (15%) of 80 phleboliths, we did not observe this sign at stones. We observed soft tissue rim sign on 21 (67%) of 31 stones. However this sign was never seen on phleboliths. Conclusion: The results of this study indicate that unenhanced helical CT has reliable findings in the differentiation of stones from phleboliths. It is easier to differentiate urinary stones from phleboliths with thin-slice CT. Applying of all criteria mentioned in this study may be useful in differentiation of distal urinary stones from phleboliths on unenhanced helical CT.

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1) Vieweg J, Teh C, Freed K, Leder RA, Smith RHA, Nelson RH, Preminger GM. Unenhanced helical computerized tomography for the evaluation of patients with acute flank pain. J Urol 1998; 160: 679-684.
2) Katz DS, Lane MJ, Sommer FG. Unenhanced helical CT of ureteral stones: incidence of associated urinary tract findings. AJR Am J Roentgenol 1996; 166: 1319-1322.
3) Smith RC, Levine C, Rosenfeld A. Helical CT of urinary stones: Epidemiology, origin, pathophysiology, diagnosis, and management. Radiol Clin North Am 1999; 37: 911-952.
4) Bell TV, Fenlon HM, Davison BD, Ahari HK, Hussain S. Unenhanced helical CT criteria to differentiate distal ureteral calculi from pelvic phleboliths. Radiology 1998; 207: 363-367.
5) Fielding JR, Steele G, Fox LA, Heller H, Loughlin KR. Spiral computerized tomography in the evaluation of acute flank pain: a replacement for excretory urography. J of Urol 1997; 157: 2071-2073.
6) Heneghan JP, Dalrymple NC, Verga M, Rosenfield AT, Smith RC. Soft-tissue ‘rim' sign in the diagnosis of ureteral calculi with use of unenhanced helical CT. Radiology 1997; 202: 709-711.
7) Traubici J, Neitlich JD, Smith RC: Distinguishing pelvic phleboliths from distal ureteral stones on routine unenhanced helical CT. Is there a radiolucent center? AJR 1999; 172: 13-17.
8) Arac M, Celik H, Oner AY, Gultekin S, Gumus T, Kosar S. Distinguishing pelvic phleboliths from distal ureteral calculi: thin-slice CT findings. Eur Radiol 2005; 15: 65-70.
9) Mindell HJ, Herschorn SD, Dash A, et al. In vitro CT comparisons of dissected phleboliths and retrieved ureteral calculi. Emergency Radiology 2001; 8: 332-334.
10) Fox LA, Fielding JR, Seltzer SE. Differentiation between pelvic ureteral calculi and phleboliths: spiral CT image analysis AJR 1997; 168: 68-71.
11) Boridy IC, Nikolaidis P, Kawashima A, Goldman SM, Sandler CM. Ureterolithiasis: value of the tail sign in differentiating phleboliths from ureteral calculi at nonenhanced helical CT 1999; 211: 619-621.