Prostatome: A combined anatomical and disease based MRI atlas of the prostate

• Published in: Medical physics (Lancaster) 2014-07, Vol.41 (7), p.072301-n/a
• Main Authors: Rusu, Mirabela, Bloch, B. Nicolas, Jaffe, Carl C., Genega, Elizabeth M., Lenkinski, Robert E., Rofsky, Neil M., Feleppa, Ernest, Madabhushi, Anant
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Aggregation; Algorithms; anatomic imaging atlas; Anatomy; Atlases as Topic; Biological material, e.g. blood, urine; Haemocytometers; Biomedical imaging; Biomedical modeling; biomedical MRI; BIOPSY; BRAIN; Cancer; Clinical applications; COMPARATIVE EVALUATIONS; CORRELATIONS; Digital computing or data processing equipment or methods, specially adapted for specific applications; diseases; guided biopsy; HISTOLOGY; Humans; Image data processing or generation, in general; IMAGE PROCESSING; Image Processing, Computer-Assisted; image registration; IN VIVO; in vivo imaging; Involving electronic [emr] or nuclear [nmr] magnetic resonance, e.g. magnetic resonance imaging; Magnetic Resonance Imaging; Magnetic Resonance Physics; Male; medical image processing; Medical image segmentation; MRI anatomic imaging; NEOPLASMS; NMR IMAGING; PATHOLOGY; PROSTATE; Prostate - anatomy & histology; Prostate - pathology; prostate cancer; Prostatectomy; Prostatic Neoplasms - pathology; Prostatic Neoplasms - surgery; Registration; Spatial analysis; statistical analysis; surgery; Surgical instruments, devices or methods, e.g. tourniquets; URINARY TRACT
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.4881515

Purpose: In this work, the authors introduce a novel framework, the anatomically constrained registration (AnCoR) scheme and apply it to create a fused anatomic‐disease atlas of the prostate which the authors refer to as the prostatome. The prostatome combines a MRI based anatomic and a histology based disease atlas. Statistical imaging atlases allow for the integration of information across multiple scales and imaging modalities into a single canonical representation, in turn enabling a fused anatomical‐disease representation which may facilitate the characterization of disease appearance relative to anatomic structures. While statistical atlases have been extensively developed and studied for the brain, approaches that have attempted to combine pathology and imaging data for study of prostate pathology are not extant. This works seeks to address this gap. Methods: The AnCoR framework optimizes a scoring function composed of two surface (prostate and central gland) misalignment measures and one intensity‐based similarity term. This ensures the correct mapping of anatomic regions into the atlas, even when regional MRI intensities are inconsistent or highly variable between subjects. The framework allows for creation of an anatomic imaging and a disease atlas, while enabling their fusion into the anatomic imaging‐disease atlas. The atlas presented here was constructed using 83 subjects with biopsy confirmed cancer who had pre‐operative MRI (collected at two institutions) followed by radical prostatectomy. The imaging atlas results from mapping thein vivo MRI into the canonical space, while the anatomic regions serve as domain constraints. Elastic co‐registration MRI and corresponding ex vivo histology provides “ground truth” mapping of cancer extent on in vivo imaging for 23 subjects. Results: AnCoR was evaluated relative to alternative construction strategies that use either MRI intensities or the prostate surface alone for registration. The AnCoR framework yielded a central gland Dice similarity coefficient (DSC) of 90%, and prostate DSC of 88%, while the misalignment of the urethra and verumontanum was found to be 3.45 mm, and 4.73 mm, respectively, which were measured to be significantly smaller compared to the alternative strategies. As might have been anticipated from our limited cohort of biopsy confirmed cancers, the disease atlas showed that most of the tumor extent was limited to the peripheral zone. Moreover, central gland tumors were typically l