Variability in Manual Segmentation of Temporal Bone Structures in Cone Beam CT Images.

PURPOSE: Manual segmentation of anatomical structures is the accepted "gold standard" for labeling structures in clinical images. However, the variability in manual segmentation of temporal bone structures in CBCT images of the temporal bone has not been systematically evaluated using multiple reviewers. Therefore, we evaluated the intravariability and intervariability of manual segmentation of inner ear structures in CBCT images of the temporal bone. METHODS: Preoperative CBCTs scans of the inner ear were obtained from 10 patients who had undergone cochlear implant surgery. The cochlea, facial nerve, chorda tympani, mid-modiolar (MM) axis, and round window (RW) were manually segmented by five reviewers in two separate sessions that were at least 1 month apart. Interreviewer and intrareviewer variabilities were assessed using the Dice coefficient (DICE), volume similarity, mean Hausdorff Distance metrics, and visual review. RESULTS: Manual segmentation of the cochlea was the most consistent within and across reviewers with a mean DICE of 0.91 (SD = 0.02) and 0.89 (SD = 0.01) respectively, followed by the facial nerve with a mean DICE of 0.83 (SD = 0.02) and 0.80 (SD = 0.03), respectively. The chorda tympani had the greatest amount of reviewer variability due to its thin size, and the location of the centroid of the RW and the MM axis were also quite variable between and within reviewers. CONCLUSIONS: We observed significant variability in manual segmentation of some of the temporal bone structures across reviewers. This variability needs to be considered when interpreting the results in studies using one manual reviewer.

Clinical outcomes following endoscopic or video-assisted retroperitoneal management of acute pancreatitis with large (>15 cm) walled-off pancreatic necrosis: Retrospective, single tertiary center cohort study.

OBJECTIVE: Acute pancreatitis with walled-off necrosis (WON) is associated with considerable morbidity and mortality. Previous studies have evaluated outcomes in WON collections of limited size, while data about large WON with long-term follow-up are lacking. We aimed to report our experience in managing large WON. METHODS: Between 2010 and 2020, consecutive patients with large (>15 cm) WON were identified from a prospectively maintained database. Patients with chronic pancreatitis or an index intervention 90 days or more from the debut of symptoms were excluded. We registered clinical and technical outcomes following minimally invasive treatment in WON >15 cm. Follow-up was a minimum of 1 year. RESULTS: Overall, 144 patients with WON >15 cm, with a median age of 60 (interquartile range [IQR] 49-69) years, were included. The median WON size was 19.2 cm (IQR 16.8-22.1). Most patients were treated with endoscopic transluminal drainage (93%). The median length of stay was 53 days (IQR 39-76) and 61 (42%) patients needed intensive care support during their hospital stay. As 143 patients (99%) were managed using endoscopic or video-assisted retroperitoneal techniques, only one (0.7%) patient needed an open necrosectomy. Procedure-related adverse events occurred in 10 (7%) patients. Overall, 24 patients (17%) died during admission, all due to multiorgan failure. The median follow-up was 35 months (IQR 15-63.5). Complete resolution was achieved in all remaining patients. CONCLUSION: Minimally invasive treatment of large WON is feasible, with a minimal need for surgery and acceptable rates of morbidity and mortality.