Objective The Global Leadership Initiative on Malnutrition (GLIM) has proposed criteria for the diagnosis of malnutrition, one of which is reduced muscle mass. Computed tomography (CT) assessment of psoas muscle area (PMA) has been used to estimate muscle mass in patients, including those with acute pancreatitis (AP). The present study aimed to define the cutoff value of PMA indicative of reduced muscle mass in patients with AP and to assess the impact of reduced muscle mass on the severity and early complications of AP. Methods Clinical data of 269 patients with AP were analyzed retrospectively. The severity of AP was determined according to the revised Atlanta classification. PMA was evaluated by CT and used to calculate the psoas muscle index (PMI). Cutoff values for reduced muscle mass were calculated and validated. Logistic regression analysis was performed to assess the relationship between PMA and the severity of AP. Results PMA was a better indicator of reduced muscle mass than PMI, with cutoff values of 11.50 cm 2 for men and 8.22 cm 2 for women. Rates of local complications, splenic vein thrombosis, and organ failure were significantly higher in AP patients with low than high PMA (all p < 0.05). PMA showed good ability to predict splenic vein thrombosis in women, with an area under the receiver operating characteristic curve of 0.848 (95% confidence interval 0.768–0.909, sensitivity 100%, specificity 83.64%). Multivariate logistic regression revealed that PMA was an independent risk factor for moderately severe plus severe AP (odds ratio 5.639, p = 0.001) and severe AP (odds ratio 3.995, p = 0.038). Conclusion PMA is a good predictor of the severity and complications of AP. The PMA cutoff value is a good indicator of reduced muscle mass.

Background: To explore the value of MRI upon diagnosis of ischiofemoral impingement syndrome (IFI) and to recognise deformation or oedema of the quadratus femoris muscle. MRI applied to measure the ischial femoral space (IFS), the average width of quadratus femoral space (QFS), and the ischial intertuberal diameter. Methods: A retrospective analysis was carried out of 213 hip joints MRI images of 58 cases diagnosed with IFI and 61 cases of normal subjects. IFS, QFS and ischial intertuberal diameter were measured by axial T1WI sequence. The morphological and signal changes of the quadratus femoris muscle were observed through proton density weighted image fat suppression sequence (PDWI-FS). Results: The widths of IFS and QFS in the normal group were larger than those in the case group, while the ischial intertuberal diameter was significantly smaller ( p < 0.05). Pearson correlation analysis revealed that there was a positive correlation ( r = 0.824) between IFS and QFS in all hip joints and a negative correlation between the ischial intertuberal diameter and the widths of IFS and QFS ( r = −0.213, −0.222, p < 0.05) respectively. As the grade of oedema in quadratus femoris muscle increased, the corresponding IFS gradually decreased. The corresponding IFS width of grade 0 oedema of the quadratus femoris muscle oedema was significantly higher than that of grade 1, grade 2 and grade 3. The receiver operating characteristic curve (ROC) of the subjects was applied to determine the diagnostic boundary value of the IFS and QFS in IFI patients, which was 1.98 cm and 1.05 cm respectively. The area under the curve (AUC) was 0.948 and 0.953 respectively. Conclusions: MRI examination could provide a reliable basis for the diagnosis of ischiofemoral impingement syndrome. The narrowing of IFS and QFS with deformation and oedema in the quadratus femoris muscle may be the features of manifestation of IFI.