The utility of diffusion-weighted imaging in differentiation of papillary and clear cell subtypes of renal cell carcinoma

OBJECTIVE: To determine the utility of diffusion-weighted imaging (DWI) in differentiation of papillary and clear cell subtypes of renal cell carcinoma (RCC).
METHODS: A total of 16 patients with papillary RCC and clear cell RCC were enrolled in this retrospective study. Patients underwent MRI with a 3.0-Tesla wholebody system (MAGNETOM Verio, Siemens, Erlangen, Germany) using a standard body matrix coil. Apparent diffusion coefficient (ADC) values and signal intensity (SI) values at b=50 s/mm2 b=1000 s/mm2 DWI of solid components of the renal masses and SI values of normal renal parenchyma were measured. A freehand ROI was drawn around the peripheral margin of the tumor on the diffusion images excluding the cystic or necrotic portions, while referring to the T2-weighted conventional images for verification of lesion boundaries. To measure SI values of normal renal parenchyma, ROIs were placed on the normal corticomedullary junction.
RESULTS: Mean ADC value was statistically significantly lower in papillary RCC (0.991 ± 0.143×10ˉ³ mm²/s) than in that of clear cell RCC (1.296 ±.0.277 × 10ˉ³ mm²/s). For the papillary RCC group, there was statistically significant difference (p<0.05) between mean SI values of normal parenchyma (22.8 ± 6.3) and lesion (43.4± 14.8) at b=1000 s/mm2 DWI; for the clear cell RCC group there was statistically significant difference (p<0.05) between mean SI value of normal parenchyma (138.8 ± 33) and lesion (102± 27.5) at b=50 s/mm2 DWI.
CONCLUSION: For discrimination of papillary and clear cell subtypes of RCC, DWI seems to be a useful method. The boundaries of papillary RCC can be more clearly perceived on b=1000 s/mm2 and that of clear cell RCC on b=50 s/mm2 DWI. However, more extensive research on a larger series of patients are needed to support our findings.

Renal hücreli kanserde difüzyon aðýrlýklý MR görüntüleme kullanýlarak papiller ve þeffaf hücreli subtiplerin ayýrt edilmesi

AMAÇ: Bu çalýþmadaki amacýmýz, renal hücreli kanser (RHK) ' in papiller ve þeffaf alt tiplerinin ayýrt edilmesinde difüzyon aðýrlýklý görüntüleme (DAG) ' nin yararlýlýðýný saptamaktýr.
YÖNTEMLER: Papiller tip ve þeffaf hücreli tip RHK ' li toplam 16 olgu retrospektif olarak deðerlenmiþtir. Ýnceleme 3 Tesla alan gücüne sahip manyetik rezonans cihazýnda gerçekleþtirilmiþtir. Renal kitle konturlarý T2 aðýrlýklý görüntülerden de faydalanýlarak sýnýrlanmýþ ve kistik-nekrotik dejenerasyon alanlarý dýþarýda kalacak þekilde elle çizilen ilgi alaný (freehand ROI) kullanýlarak kitlelerin solid komponentlerinin b=50 sn/mm2 ve b=1000 sn/mm2 DAG’lerde görünür difüzyon katsayý (apparent diffusion coefficient =ADC) deðerleri ve ortalama sinyal intensite (SI) deðerleri ile böbreðin normal parankiminin ortalama SI deðerleri ölçülmüþtür. Normal parankimin SI deðerlerinin ölçümü için ROI kortikomedüller bileþkeye yerleþtirilmiþtir.


BULGULAR: Ortalama ADC deðeri papiller RHK’ larda (0.991 ± 0.143×10ˉ³ mm²/sn) þeffaf hücreli RHK’ lardan istatistiksel olarak anlamlý derecede düþüktü (1.296 ± 0.277 × 10ˉ³ mm²/sn) (p<0.05). Ayrýca papiller RHK grubunda, b=1000 sn/mm2 DAG’lerde ölçülen ortalama SI deðerleri (22.8 ± 6.3), normal parankimden (43.4± 14.8); þeffaf hücreli RHK grubunda b=50 sn/mm2 DAG’ lerde ölçülen ortalama SI deðerleri (102± 27.5), normal parankimden (138.8 ± 33) istatistiksel olarak farklýydý (p<0.05).
SONUÇ: Papiller ve þeffaf hücreli kanser subtiplerinin ayýrt edilebilmesinde difüzyon aðýrlýklý görüntüleme faydalý bir yöntem olabilir. Papiller hücreli kanserlerin sýnýrlarý, b=1000 sn/mm2; þeffaf hücreli kanserlerin sýnýrlarý ise b=50 sn/mm2 DAG’lerde daha net olarak seçilebilmektedir. Bulgularýmýzýn desteklenmesi için daha geniþ hasta serisini kapsayan çalýþmalara gereksinim vardýr.