The patella-patellar tendon angle (PPTA) assessing the sagittal patellar tilt was reported to be related with anterior knee pain. Herein, clinical effect of PPTA in patients with medial patellar plica (MPP) syndrome, chondromalacia patella, and infrapatellar fat pad (IPFP) syndrome, the most common causes of anterior knee pain, was evaluated. In this retrospective study, 156 patients with anterior knee pain who underwent magnetic resonance imaging (MRI) and arthroscopic surgery that confirmed isolated MPP syndrome, chondromalacia patella, or IPFP syndrome from June 2011 to January 2021 were included in the study group and 118 patients without knee pathology on MRI during the same period were included in the control group. The PPTA was measured on knee MRI and compared between the two groups. A receiver operating characteristic (ROC) analysis was used to evaluate the value of PPTA for predicting the risk of patellofemoral joint disorder. The mean PPTA was significantly smaller in study group (138.1 ± 4.2°) than control group (142.1 ± 4.3°) (p < 0.001). However, there was no significant difference in PPTA among the patients with MPP syndrome, chondromalacia patella, and IPFP syndrome. Furthermore, the ROC analysis revealed that the area under curve, sensitivity, and specificity for predicting the risk of patellofemoral joint disorders were 0.696, 70.3% and 57.6%, respectively, at a PPTA cutoff of 138.3°. Therefore, the smaller PPTA may be associated with MPP syndrome, chondromalacia patella, and IPFP syndrome. Furthermore, PPTA could be a predictive factor for the risk of patellofemoral joint disease in patients with anterior knee pain.

Iliotibial band friction syndrome (ITBFS), commonly seen in young individuals who engage in physical activi-ties such as running, cycling, or weightlifting, is one of the common causes of lateral knee pain. ITBFS is an overuse injury and is thought to be caused by inflammation of distal part of the ITB due to the repetitive friction and

To assess the feasibility of the use of spin-echo echo-planar imaging (SE-EPI) magnetic resonance elastography (MRE) in livers of children and young adults. Materials and Methods: Patients (≤ 20 years old) who underwent 3T SE-EPI MRE were included retrospectively. Subjects were divided into three groups according to the purpose of the liver MRI: suspicion of fatty liver or focal fat deposition in the liver (FAT group), liver fibrosis after receiving a Kasai operation from biliary atresia (BA group), and hepatic iron deposition after receiving chemotherapy or transfusions (IRON group). Technical failure of MRE was defined when a stiffness map showed no pixel value with a confidence index higher than 95%, and the patients were divided as success and failure groups accordingly. Clinical findings including age, gender, weight, height, and body mass index and magnetic resonance imaging results including proton density fat fraction (PDFF), T2*, and MRE values were assessed. Factors affecting failure of MRE were evaluated and the image quality in wave propagation image and stiffness map was evaluated using the appropriate scores. Results: Among total 240 patients (median 15 years, 211 patients in the FAT, 21 patients in the BA, and 8 patients in the IRON groups), technical failure was noted in six patients in the IRON group (6/8 patients, 75%), while there were no failures noted in the FAT and BA groups. These six patients had T2* values ranging from 0.9 to 3.8 ms. The image quality scores were not significantly different between the FAT and BA groups (P > 0.999), while the scores were significantly lower in the IRON group (P < 0.001). Conclusion: The 3T SE-EPI MRE in children and young adults had a high technical success rate. The technical failure was occurred in children with decreased T2* value (≤ 3.8 ms) from iron deposition.

Background: In patients treated with curative surgery for colorectal cancer, the single-phase (portal phase) abdomen-pelvic computed tomography (CT) follow-up is routinely performed to detect any recurrent lesions. Objective: To evaluate CT features implying metastasis in newly appearing hepatic lesions on single-phase CT after colorectal cancer surgery. Method: Of 1,227 patients who underwent curative colorectal surgery between 2011 and 2014, 267 patients with new hepatic lesions on follow-up single-phase CT (metastasis, n=192; benign, n=75) were included. The CT features of the hepatic lesions were analyzed by two radiologists, retrospectively, and clinical information including carcinoembryonic antigen (CEA) level was also reviewed. The risk factors for hepatic metastasis were evaluated by multivariable logistic regression. Results: In this study, independent CT features associated with metastasis were spherical shape (p < 0.001), circumscribed margin (p = 0.021), heterogeneous attenuation (p = 0.024) and bulging appearance (p = 0.007). Among the clinical factors, increased CEA level (p = 0.013), higher preoperative stage (p = 0.014) and lymphovascular invasion (p = 0.003) were associated with metastasis. However, on multivariable analysis, spherical shape was the only significant predictive factor for hepatic metastasis. The diagnostic performance of ‘spherical shape’ for detection of hepatic metastasis showed accuracy of 84.6%, sensitivity of 83.9%, and specificity of 86.7%. Conclusion: Specific single-phase CT features could be useful in distinguishing hepatic metastasis from benign, resulting in continuing routine CT follow-up without liver magnetic resonance imaging (MRI) when metastasis is unlikely.

Background There was a lack of studies assessing the relationship between deep vein thrombosis (DVT) Hounsfield unit (HU) density and pulmonary thromboembolism (PTE). Purpose To evaluate the clinical value of DVT density measured on pre- and post-contrast lower-extremity computed tomography (CT) for the prediction of PTE. Material and Methods From 2017 to 2021, patients who underwent pulmonary CT angiography within one week after diagnosis of DVT on lower-extremity CT were included in this retrospective study. Then, the patients without PTE were included in “DVT group” and those with both DVT and PTE were included in the “DVT-PTE group.” The DVT HU density was measured by drawing free-hand region of interests (ROIs) within the thrombus at the most proximal filling defect level. A receiver operating characteristic (ROC) analysis was used to evaluate the predictive value of DVT density for the risk of PTE. Results This study included a total of 94 patients (DVT group: n=56; DVT-PTE group: m=38). DVT density was significantly higher in the DVT-PTE group than the DVT group in both pre-contrast (53.5 ± 6.2 HU vs. 44.1 ± 7.9 HU; P < 0.001) and post-contrast CT (67.0 ± 8.6 HU vs. 57.1 ± 10.6 HU; P < 0.001). ROC analysis revealed that the area under curve, sensitivity, and specificity for predicting the risk of PTE were 0.739, 71.1%, and 64.2%, respectively, at a DVT density cutoff of 48.2 HU on pre-contrast CT and were 0.779, 73.7%, and 69.6% at a DVT density cutoff of 61.8 HU on post-contrast CT. Conclusion The DVT density on both pre- and post-contrast CT could be a predictive factor of PTE.