Yousef Mazaheri PhD, Presenter: Nothing to Disclose

Hedvig Hricak MD, PhD, Abstract Co-Author: Nothing to Disclose

Samson W. Fine MD, Abstract Co-Author: Nothing to Disclose

Oguz Akin MD, Abstract Co-Author: Nothing to Disclose

Amita Shukla-Dave PhD, Abstract Co-Author: Nothing to Disclose

Jingbo Zhang MD, Abstract Co-Author: Nothing to Disclose

Nicole M. Ishill PhD, Abstract Co-Author: Nothing to Disclose

Chaya Moskowitz, Abstract Co-Author: Nothing to Disclose

Victor Reuter MD, Abstract Co-Author: Nothing to Disclose

Peter T Scardino MD, Abstract Co-Author: Nothing to Disclose

Kristen Lynne Zakian PhD, Abstract Co-Author: Nothing to Disclose

Jason Arthur Koutcher MD, PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To retrospectively measure the sensitivity and specificity of diffusion-weighted imaging (DWI) for identifying cancer in prostate peripheral zone (PZ) tissue and assess the accuracy of tumor volume measurement performed with T2-weighted MRI and combined T2-weighted MRI/DWI, using surgical pathology as the reference standard.

The institutional review board issued a waiver of informed consent for this HIPAA-compliant study. Forty-two patients (median age, 62 years; range, 42–72 years) underwent 1.5T endorectal MRI before radical prostatectomy for prostate cancer and had at least one PZ tumor >0.1 cm3 on surgical pathology. Apparent diffusion coefficient (ADC) cut-off values to discriminate malignant PZ tissue were determined from a voxel-wise analysis. On T2-weighted MRI, two independent readers outlined regions-of-interest (ROIs) in the PZ thought to represent tumor. Cluster analysis of voxels within the ROIs was performed on ADC maps. Associations between volume measurements from imaging and pathology were assessed with concordance correlation coefficients (CCCs).

Sensitivity/specificity of ADC cut-off values 0.0013, 0.00145, and 0.0016 mm2/s were 72%/92%, 86%/81%, and 95%/65%, respectively, in identifying malignant voxels. The readers detected 45/60 (75%) and 43/60 (71.7%) tumor nodules. CCCs (95% CI) were 0.36(0.14,0.57) for T2-weighted MRI, and 0.27(0.05,0.48), 0.49(0.23,0.75) and 0.60(0.38,0.83) for combined T2-weighted/DWI using cutoffs 0.0013, 0.00145 and 0.0016 mm2/s, respectively. The CCC for combined T2-weighted MRI/DWI (cutoff = 0.0016 mm2/s) was significantly higher (P=0.006) than that for T2-weighted MRI alone in tumor volume measurement.

Combined T2-weighted MRI/DWI is significantly more accurate than T2-weighted MRI alone in PZ tumor volume measurement.

Prostate cancer tumor volume measurements with combined T2-weighted MRI and DWI can be useful in making decisions regarding treatment selection and planning.

Mazaheri, Y, Hricak, H, Fine, S, Akin, O, Shukla-Dave, A, Zhang, J, Ishill, N, Moskowitz, C, Reuter, V, Scardino, P, Zakian, K, Koutcher, J, et al, , Measurement of Prostate Cancer Tumor Volume with Combined T2-weighted MRI and Diffusion-weighted Imaging: Initial Results.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6022461.html