Texture Analysis of Fractional Water Content Images Acquired during PET/MRI: Initial Evidence for an Association with Total Lesion Glycolysis, Survival and Gene Mutation Profile in Primary Colorectal Cancer.

To assess the capability of fractional water content (FWC) texture analysis (TA) to generate biologically relevant information from routine PET/MRI acquisitions for colorectal cancer (CRC) patients. Thirty consecutive primary CRC patients (mean age 63.9, range 42-83 years) prospectively underwent FDG-PET/MRI. FWC tumor parametric images generated from Dixon MR sequences underwent TA using commercially available research software (TexRAD). Data analysis comprised (1) identification of functional imaging correlates for texture features (TF) with low inter-observer variability (intraclass correlation coefficient: ICC > 0.75), (2) evaluation of prognostic performance for FWC-TF, and (3) correlation of prognostic imaging signatures with gene mutation (GM) profile. Of 32 FWC-TF with ICC > 0.75, 18 correlated with total lesion glycolysis (TLG, highest: rs = -0.547, p = 0.002). Using optimized cut-off values, five MR FWC-TF identified a good prognostic group with zero mortality (lowest: p = 0.017). For the most statistically significant prognostic marker, favorable prognosis was significantly associated with a higher number of GM per patient (medians: 7 vs. 1.5, p = 0.009). FWC-TA derived from routine PET/MRI Dixon acquisitions shows good inter-operator agreement, generates biological relevant information related to TLG, GM count, and provides prognostic information that can unlock new clinical applications for CRC patients.

FDG-PET/CT in colorectal cancer: potential for vascular-metabolic imaging to provide markers of prognosis.

PURPOSE: This study assesses the potential for vascular-metabolic imaging with FluoroDeoxyGlucose (FDG)-Positron Emission Tomography/Computed Tomography (PET/CT) perfusion to provide markers of prognosis specific to the site and stage of colorectal cancer. METHODS: This prospective observational study comprised of participants with suspected colorectal cancer categorized as either (a) non-metastatic colon cancer (M0colon), (b) non-metastatic rectal cancer (M0rectum), or (c) metastatic colorectal cancer (M+). Combined FDG-PET/CT perfusion imaging was successfully performed in 286 participants (184 males, 102 females, age: 69.60 ± 10 years) deriving vascular and metabolic imaging parameters. Vascular and metabolic imaging parameters alone and in combination were investigated with respect to overall survival. RESULTS: A vascular-metabolic signature that was significantly associated with poorer survival was identified for each patient group: M0colon - high Total Lesion Glycolysis (TLG) with increased Permeability Surface Area Product/Blood Flow (PS/BF), Hazard Ratio (HR) 3.472 (95% CI: 1.441-8.333), p = 0.006; M0rectum - high Metabolic Tumour Volume (MTV) with increased PS/BF, HR 4.567 (95% CI: 1.901-10.970), p = 0.001; M+ participants, high MTV with longer Time To Peak (TTP) enhancement, HR 2.421 (95% CI: 1.162-5.045), p = 0.018. In participants with stage 2 colon cancer as well as those with stage 3 rectal cancer, the vascular-metabolic signature could stratify the prognosis of these participants. CONCLUSION: Vascular and metabolic imaging using FDG-PET/CT can be used to synergise prognostic markers. The hazard ratios suggest that the technique may have clinical utility.

Appendiceal mucocele secondary to torsion in an asymptomatic patient.

Torsion of the appendix associated with an appendiceal mucocele is extremely rare with just a few published cases. To our knowledge, we report the first case of appendiceal mucocele secondary to torsion in an asymptomatic patient. In this case, numerous adhesions were found attaching the tip of the appendix mucocele to the peritoneum contributing to torsion as well as a lack of evidence for appendiceal neoplasm. Complications of appendiceal mucocele include obstruction, intussusception and pseudomyxoma peritonei, which has a particularly poor prognosis. Clinicians should, therefore, consider prompt surgical resection for definitive histopathological diagnosis and management.

Long-axis rotational volvulus in a W ileoanal pouch: an unusual but potentially preventable problem. Report of a case.

PURPOSE: This study was designed to report long-axis rotational volvulus, an unusual long-term complication of restorative proctocolectomy. METHODS: A MEDLINE search using the keywords, pouch volvulus, pouch complications, ileoanal pouch volvulus, restorative proctocolectomy volvulus, restorative proctocolectomy complications, W-pouch, and early and late complications, was performed and yielded no previous reports. RESULTS: We describe pouch gangrene secondary to volvulus in a W-pouch four years after restorative proctocolectomy for ulcerative colitis. Early recognition by clinical features, pouchoscopy, and soluble contrast studies are crucial if pouch salvage by pouchpexy is to be successful. CONCLUSIONS: Acute necrosis of the ileoanal pouch caused by long-axis rotational volvulus is an important, but uncommon, cause of life-threatening acute abdomen after restorative proctocolectomy. Prophylactic pouchpexy at the time of pouch construction or salvage pouchpexy after early diagnosis of the at-risk pouch are important considerations to avoid loss of the pouch.