Development of a registration framework to validate MRI with histology for prostate focal therapy

Abstract

The authors have developed a registration framework for mapping in vivo MRI data of the prostate with histology by implementing a number of processing steps and ex vivo MRI of the prostate specimen. Validation of DIR was challenging, particularly in prostates with few or mostly linear rather than spherical shaped features. Refinement of their MR imaging protocols to improve the data quality is currently underway which may improve registration accuracy. Additional mpMRI sequences will be registered within this framework to quantify prostate tumor location and biology.

Magnetic Resonance Imaging Underestimation of Prostate Cancer Geometry: Use of Patient Specific Molds to Correlate Images with Whole Mount Pathology

“…Ex vivo MRI of specimens has also been done but only in a small number of cases. 11,12 Turkbey et al first described the use of 3D printed, patient specific molds, 13,14 which hold excised prostates in the same shape and orientation observed in vivo. Some prior work indicates that MRI provides an overestimate of tumor volume, 15,16 although these studies were based on older technologies and did not use software registration.…”

A system using patient‐specific 3D‐printed molds to spatially align in vivo MRI with ex vivo MRI and whole‐mount histopathology for prostate cancer research

“…In order to validate and improve prostate mp‐MRI, comparison with ground‐truth whole‐mount histopathology (WMHP) is an important strategy and accurate spatial alignment between the two is critical. However, it is challenging to achieve accurate spatial alignment between MRI and WMHP images, due to factors such as differences in MRI acquisition and WMHP sectioning geometries, MRI and WMHP spatial resolution and contrast, prostate tissue changes during surgery and WMHP processing, and WMHP sectioning variability …”

“…Patient‐specific molds designed according to InV can constrain prostate geometry and sectioning locations at WMHP to improve correspondence with InV . ExV of the resected prostate can provide high‐resolution spatial information to facilitate alignment between InV and WMHP slides . In addition to aiding spatial alignment, ExV has distinct advantages over InV, such as the absence of patient motion and possibility of longer scan times, which can enable ultrahigh‐resolution MRI and multicomponent quantitative diffusion MRI of PCa .…”

“…In addition, the majority of existing strategies based on patient‐specific molds do not customize the mold design for ExV or adapt the workflow to facilitate ExV. On the other hand, strategies based on ExV have only been evaluated in relatively small numbers of prostate specimens, often lack standardization of the experimental design (e.g., to achieve consistent positioning of the specimen with respect to InV), or lack integration into the clinical workflow. Recently, there have been initial investigations of alignment strategies that combine the advantages of patient‐specific molds with ExV, but only proof‐of‐concept results have been reported thus far.…”

PET and MRI: Is the Whole Greater than the Sum of Its Parts?

“…Although voxel-wise image data analysis is useful and forward-looking, its value depends on the accuracy of the alignment of the combined (histology and in vivo imaging) data that are acquired at different resolutions. In the future, studies that involve both imaging data and histology information may draw from existing expertise in registration frameworks previously set-up for correlating ex-vivo sample imaging and in-vivo whole-body assessment (26). In a clinical context, accurate spatial image volume alignment is currently possible only with the use of optimized imaging workflows and/or the adoption of motion detection and correction algorithms, which may become more routine in the future.…”