Differences in the distribution of peritoneal metastases in right- versus left-sided colon cancer on MRI.

PURPOSE: Right-sided colon tumors with peritoneal metastases (PM) are associated with a poorer prognosis than left-sided tumors. We hypothesized that a different pattern of spread could be characterized with abdominopelvic MRI. The objective of this study was to explore the spread of PM in relation to the primary tumor location on MRI. METHODS: This is a retrospective cohort study of patients with PM from colon cancer referred to be considered for CRS-HIPEC at a single tertiary referral center. Patients with colon cancer were eligible if they had undergone an abdominopelvic MRI scan following a clinical diagnosis of PM. The frequency of affected PCI regions on MRI (MRI-PCI) was assessed and compared between tumor sidedness. RESULTS: One hundred eighteen patients were included with a median age of 65 (IQR: 56-72). 46% percent were male. The median MRI-PCI was 10 (IQR: 5-16) and 8 (IQR: 4-11) for right- and left-sided tumors, respectively (p = 0.39), and the median number of affected regions was 4 (IQR: 2-7 for right-sided and IQR 2-5 for left-sided tumors). PM was most frequently found close to the primary tumor. The odds ratio of patients with PM of left sided to be affected with PM in the upper abdominal regions was 0.42 (95% CI: 0.20-0.90) and with PM on the small bowels or mesentery was 0.42 (95% CI: 0.19-0.92) over a patient with PM of right-sided colon cancer. CONCLUSION: MRI can help to assess the spread of PM in colonic cancer. In right-sided tumors, the small bowel and upper abdominal regions are more frequently affected.

Extent of Peritoneal Metastases on Preoperative DW-MRI is Predictive of Disease-Free and Overall Survival for CRS/HIPEC Candidates with Colorectal Cancer.

OBJECTIVE: The aim of this study was to determine whether the extent of peritoneal metastases (PMs) on preoperative diffusion-weighted magnetic resonance imaging (DW-MRI) can be used as a biomarker of disease-free and overall survival in patients with colorectal cancer who are considered for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). METHODS: For this retrospective cohort study, patients with PMs considered for CRS/HIPEC who underwent DW-MRI for preoperative staging in 2016-2017 were included. The DW-MRI protocol consisted of diffusion-weighted, T2-weighted, and pre- and post-gadolinium T1-weighted imaging of the chest, abdomen, and pelvis. DW-MRI images were evaluated by two independent readers to determine the extent of PMs represented by the Peritoneal Cancer Index (MRI-PCI), as well as extraperitoneal metastases. Cox regression and Kaplan-Meier analysis was performed to determine the prognostic value of DW-MRI for overall and disease-free survival. RESULTS: Seventy-eight patients were included. CRS/HIPEC was planned for 53 patients and completed in 50 patients (60.5%). Median follow-up after DW-MRI was 23 months (interquartile range 13-24). The MRI-PCI of both readers showed prognostic value for overall survival, independently of whether R1 resection was achieved (hazard ratio [HR] 1.06-1.08; p < 0.05). For the patients who received successful CRS/HIPEC, the MRI-PCI also showed independent prognostic value for disease-free survival for both readers (HR 1.09-1.10; p < 0.05). CONCLUSION: The extent of PMs on preoperative DW-MRI is an independent predictor of overall and disease-free survival and should therefore be considered as a non-invasive prognostic biomarker.

Diagnostic accuracy of MRI and ultrasound in chronic immune-mediated neuropathies.

OBJECTIVE: To assess and compare the diagnostic performance of qualitative and (semi-)quantitative MRI and ultrasound for distinguishing chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) from segmental spinal muscular atrophy (sSMA). METHODS: Patients with CIDP (n = 13), MMN (n = 10), or sSMA (n = 12) and healthy volunteers (n = 30) were included. MRI of the brachial plexus, using short tau inversion recovery (STIR), nerve-specific T2-weighted (magnetic resonance neurography [MRN]), and diffusion tensor imaging (DTI) sequences, was evaluated. Furthermore, with ultrasound, cross-sectional areas of the nerves were evaluated. Three radiologists blinded for diagnosis qualitatively scored hypertrophy and increased signal intensity (STIR and MRN), and intraobserver and interobserver agreement was assessed. For the (semi-)quantitative modalities, group differences and receiver operator characteristics were calculated. RESULTS: Hypertrophy and increased signal intensity were found in all groups including healthy controls. Intraobserver and interobserver agreements varied considerably (intraclass correlation coefficients 0.00-0.811 and 0.101-0.491, respectively). DTI showed significant differences (p < 0.05) among CIDP, MMN, sSMA, and controls for fractional anisotropy, axial diffusivity, and radial diffusivity in the brachial plexus. Ultrasound showed significant differences in cross-sectional area (p < 0.05) among CIDP, MMN, and sSMA in upper arm and brachial plexus. For distinguishing immune-mediated neuropathies (CIDP and MMN) from sSMA, ultrasound yielded the highest area under the curve (0.870). CONCLUSION: Qualitative assessment of hypertrophy and signal hyperintensity on STIR or MRN is of limited value. DTI measures may discriminate among CIDP, MMN, and sSMA. Currently, ultrasound may be the most appropriate diagnostic imaging aid in the clinical setting.

Diffusion tensor MRI of the healthy brachial plexus.

INTRODUCTION: Diffusion Tensor MRI (DT-MRI) is a promising tool for the evaluation of brachial plexus pathology. Therefore, we introduce and evaluate a fast DT-MRI protocol (8min33s scanning with 5-10 min postprocessing time) for the brachial plexus. MATERIALS AND METHODS: Thirty healthy volunteers within three age-groups (18-35, 36-55, and > 56) received DT-MRI of the brachial-plexus twice. Means of fractional-anisotropy (FA), mean-diffusivity (MD), axial-diffusivity (AD), and radial-diffusivity (RD) for the individual roots and trunks were evaluated. A stepwise forward approach was applied to test for correlations with age, sex, body-mass-index (BMI), bodysurface, height, and bodyweight. Within-subject, intra-rater, and inter-rater repeatability were assessed using Bland-Altman analysis, coefficient of variation (CV), intraclass-correlation (ICC), and minimal detectable difference (MDD). RESULTS: No differences between sides and root levels were found. MD, AD, and RD correlated (P < 0.05) with bodyweight. Within-subject quantification proved repeatable with CVs for FA, MD, AD, and RD of 16%, 12%, 11%, and 14%, respectively. DISCUSSION: The DT-MRI protocol was fast and repeatable. Found correlations should be considered in future studies of brachial plexus pathology.