Technical Note: Method to correlate whole‐specimen histopathology of radical prostatectomy with diagnostic MR imaging

Abstract

Purpose: Validation of MRI-guided tumor boundary delineation for targeted prostate cancer therapy is achieved via correlation with gold-standard histopathology of radical prostatectomy specimens. Challenges to accurate correlation include matching the pathology sectioning plane with the in vivo imaging slice plane and correction for the deformation that occurs between in vivo imaging and histology. A methodology is presented for matching of the histological sectioning angle and position to the in vivo imaging slices. Methods: Patients (n = 4) with biochemical failure following external beam radiotherapy underwent diagnostic MRI to confirm localized recurrence of prostate cancer, followed by salvage radical prostatectomy. High-resolution 3-D MRI of the ex vivo specimens was acquired to determine the pathology sectioning angle that best matched the in vivo imaging slice plane, using matching anatomical features and implanted fiducials. A novel sectioning device was developed to guide sectioning at the correct angle, and to assist the insertion of reference dye marks to aid in histopathology reconstruction. Results: The percentage difference in the positioning of the urethra in the ex vivo pathology sections compared to the positioning in in vivo images was reduced from 34% to 7% through slicing at the best match angle. Reference dye marks were generated, which were visible in ex vivo imaging, in the tissue sections before and after processing, and in histology sections. Conclusions: The method achieved an almost fivefold reduction in the slice-matching error and is readily implementable in combination with standard MRI technology. The technique will be employed to generate datasets for correlation of whole-specimen prostate histopathology with in vivo diagnostic MRI using 3-D deformable registration, allowing assessment of the sensitivity and specificity of MRI parameters for prostate cancer. Although developed specifically for prostate, the method is readily adaptable to other types of whole tissue specimen, such as mastectomy or liver resection. C 2016 American Association of Physicists in Medicine. [http://dx

MR elastography to measure the effects of cancer and pathology fixation on prostate biomechanics, and comparison withT1,T2and ADC

“…However, to assist in correlation with in vivo diagnostic imaging, pathology sectioning was carried out parallel to the in vivo imaging plane (axial to the endorectal coil). The registration steps were carried out in Matlab: 1) The high resolution 3D isotropic T2w data was resampled at the axial oblique angle that best matched in vivo imaging, and the angle was chosen in the manner described in (McGrath et al , 2016), where the distances from the urethra to the anterior, posterior, left and right outer edges of the prostate were measured and compared; 2) The digitized histology slides were visually matched and rigidly registered to the resampled T2w ex vivo images, by finding the best match with regard to the position of the urethra and the shape of the prostate boundary; 3) A digital tumor volume was created from the co-registered histology images through 3D interpolation; 4) The tumor volume was digitally resampled to the ex vivo MRE slice angle. The estimated angle between the in vivo and ex vivo prostate imaging slice planes for all four clinical specimens was on average 18(±9)°.…”

“…This study reports the MRE data for the clinical prostatectomy specimens, and the MRI parameter (T 1 , T 2 and ADC) data for both the canine and clinical specimens, and further analyzes and compares the MRE data with the MRI parameters for the canine and clinical specimens. The processes described for the clinical specimens form part of a pathology correlation pipeline described in (McGrath et al , 2016). …”

Prostate cancer assessment using MR elastography of fresh prostatectomy specimens at 9.4 T

“…A limitation of this approach is that an anatomic segment of the prostate contains both transition and peripheral zones of the gland, which can contain unique nonmalignant pathology. Further development of a registering method between histologic tumor annotations and radiologic imaging is desirable but still in an experimental stage . Third, ex vivo imaging results differ from the results acquired under in vivo conditions; therefore, clinical applicability is limited.…”

“…Further development of a registering method between histologic tumor annotations and radiologic imaging is desirable but still in an experimental stage. [26][27][28] Third, ex vivo imaging results differ from the results acquired under in vivo conditions; therefore, clinical applicability is limited. Contributing factors include (1) 9.4T magnet at room temperature versus 1.5T or 3T magnet at body temperature, (2) 500-Hz shear waves ex vivo versus 60-120 Hz in vivo, and (3) no surrounding soft tissue ex vivo versus substantial attenuation in a clinical setting.…”

MR visible localization device for radiographic-pathologic correlation of surgical specimens

“…They showed that preoperative MRI datasets matched confidently with histopathology using uniform slice thickness and slice angles. Furthermore, different devices have been developed for sectioning prostatectomy specimen, that facilitate comparison between histology and in vivo MRI [10,11]. The device present in this work, allows for a similar comparison between MR Images and gross pathologic assessment.…”