Anna Vignati, Presenter: Nothing to Disclose

Valentina Giannini, Abstract Co-Author: Nothing to Disclose

Simone Mazzetti, Abstract Co-Author: Nothing to Disclose

Filippo Russo MD, Abstract Co-Author: Nothing to Disclose

Christian Bracco PhD, Abstract Co-Author: Speaker, Bracco Group Speaker, ABC Medical Imaging Consultant, Bayer AG

Michele Stasi, Abstract Co-Author: Nothing to Disclose

Daniele Regge MD, Abstract Co-Author: Nothing to Disclose

Improving accuracy of risk assessment in prostate cancer (PCa) patients represents today a compelling clinical need. While it is well know that PCa usually shows a lower signal intensity (SI) than non-neoplastic prostatic tissue on T2-weighted (T2w) magnetic resonance imaging (MRI), its value in differentiating PCa aggressiveness is unknown. The propose of this study is to investigate if T2w SI correlates with the pathological Gleason Score (pGS), the reference standard for measuring the biological activity of PCa.

The study dataset comprises 31 men (64 y, mean age) with biopsy proven PCa including: 9 men with pGS 3+3 tumours, 11 with pGS 3+4, 5 with pGS 4+3, and 6 with pGS 4+4. All patients underwent multiparametric MRI with a 1.5 T scanner and endorectal coil, including a T2w axial scan (TR/TE, 2960/85 ms; FOV, 16 cm; slice thickness, 3 mm; acquisition matrix, 384 x 288). Data were processed with in-house developed software packages based on C++ algorithms and ITK libraries. First, intensity inhomogeneity correction field was performed by the combination of a phantom intensity profile and a proper median smoothing of the original T2w image. Second, from the central 2D image of the T2w volume, the coil was segmented by a Hough transformation. Finally, a k-means algorithm and morphological operations were performed to automatically extract the obturator muscles (OBT). The T2w volume was then normalized by the median value of the OBT. The Pearson correlation coefficient (R) was calculated to assess if there was a correlation between tumour aggressiveness, based on pGS, and T2w signal.

Mean value ± SD of T2 values for the different pGS group were: 2.63±0.67 for pGS 3+3; 2.19±0.57 for pGS 3+4; 1.74±0.31 for pGS 4+3; 1.81±0.13 for pGS 4+4. R showed a moderate correlation (R=-0.63) between tumours with pGS 3+3 and those with 4+4.

Preliminary findings suggest that T2 SI could be a reliable imaging marker to predict PCa risk of progression. T2 SI may be considered as an additional feature in computer-aided diagnosis (CAD) schemes.

An imaging marker of cancer aggressiveness, measurable before surgery, could contribute to stratify patients with PCa according to their progression risk, thus improving individual treatment strategy.

Vignati, A, Giannini, V, Mazzetti, S, Russo, F, Bracco, C, Stasi, M, Regge, D, MR-T2-weighted Signal Intensity: A New Imaging Marker of Prostate Cancer Aggressiveness.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13044355.html