Ettore Squillaci MD, Presenter: Nothing to Disclose

Guglielmo Manenti MD, Abstract Co-Author: Nothing to Disclose

Mauro Di Roma MD, Abstract Co-Author: Nothing to Disclose

Stefano Mancino MD, Abstract Co-Author: Nothing to Disclose

Marco Carlani MD, Abstract Co-Author: Nothing to Disclose

Giovanni Simonetti MD, Abstract Co-Author: Nothing to Disclose

To correlate ADC values of diffusion-weighted (DW) MR imaging with tumor cellularity in benign and malignant renal tumors.

10 normal volunteers and 36 patients with histologically proven renal lesions (18 clear cell ca, 4 cystic renal cell ca, 2 granular ca, 4 oncocytomas, 8 angiomyolipomas) underwent MRI of the kidneys by using a 3 T superconductive magnet. Diffusion-weighted images were obtained on axial plane during breath-hold with a SE EPI single shot sequence with b value of 500 s/mm2. All lesions were surgically resected and the mean tumor cellularity was calculated. For each case 10 high power fields were evaluated. Comparison between tumor cellularity and the mean ADCs were performed using simple linear regression analysis. A p value < 0.01 was considered statistically significant.

ADC values in normal renal parenchyma ranged from 1.72 ± 0.15 x 10-3 mm2/s to 2.65 ± 0.34 x 10-3 mm2/s, while ADC values in solid benign and malignant renal tumors showed ADC values ranging between 1.28 ± 0.11 x 10-3 mm2/s and 2.23 ± 0.43 x 10-3 mm2/s. (1.5 ± 0.8 for clear cell ca, 2.44 ± 0.4 for cystic cell ca, 2.67 ± 0.9 for granular cell ca, 1.71 ± 0,3 for oncocytoma and 1.46 ± 0.009 for angiomyolipoma). Most of the malignant tumors showed higher signal intensity on DWI compared with benign renal lesions. The mean ADC values of renal lesions (both benign and malignant) correlate with tumour cellularity in a 32/36 patients. Malignant renal tumors had higher cellularity than benign renal tumours, and they showed significant lower ADC values compared to benign tumors. There was no overlap of ADC values between normal renal parenchyma and solid renal tumors, except for one case of clear cell carcinoma. There is no statistically significative difference between ADC values of clear cell carcinoma and oncocytoma while tumor cellularity is significative higher in oncocytomas.

DW MR at 3T is a feasible a reliable technique to differentiate renal tumors on the basis of different ADC values. Larger series are necessary to correlate ADC and cellularity of different hystotypes.

Squillaci, E, Manenti, G, Di Roma, M, Mancino, S, Carlani, M, Simonetti, G, Correlation between ADC Values of Diffusion-weighted MR Imaging and Cellularity in Renal Tumors with 3T MR Unit.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4405366.html