Assessment of Imaging Factors Associated with Baker's Cyst Rupture on Knee MRI.

Objectives: To identify the factors associated with Baker's cyst rupture on MRI. Material and methods: From January 2021 to December 2022, a total of 441 knee MRI examinations in 441 patients (mean age: 47.7 ± 13.8 years) with Baker's cyst were included in this study. Patients were classified into two groups: those with ruptured vs. unruptured Baker's cysts. On knee radiograph, osteoarthritis grade was assessed based on Kellgren-Lawrence grade. On MRI, combined structure injuries, alignment type between semimembranosus tendon and medial head of gastrocnemius tendon, amount of joint effusion, presence of septation, maximal diameters of cyst, and cyst volume were evaluated. Receiver operating characteristic (ROC) analysis was performed to assess the predictive performances of imaging factors for cyst rupture. Results: There were 146 patients with Baker's cyst rupture and 295 patients without rupture. Patients with cyst rupture showed significantly longer maximal transverse diameter (25.8 ± 6.8 mm vs. 21.6 ± 5.8 mm, p = 0.035) and larger volume (13.3 ± 6.2 cm3 vs. 9.9 ± 5.1 cm3, p = 0.012) than those without rupture. On ROC analysis, maximal transverse diameter of cyst ≥ 22.2 mm (sensitivity = 64.4%, specificity = 54.9%) and cyst volume ≥ 10.9 cm3 (sensitivity = 71.2%, specificity = 58.3%) were the cutoff values for predicting rupture of cyst, respectively. The cyst volume showed significantly higher area under the curve (AUC) than maximal transverse diameter (0.726 vs. 0.642, p = 0.002). Conclusion: Longer transverse diameter and larger volume of Baker's cyst could be predictive imaging parameters for cyst rupture.

Detection of Pacemaker and Identification of MRI-conditional Pacemaker Based on Deep-learning Convolutional Neural Networks to Improve Patient Safety.

With the increased availability of magnetic resonance imaging (MRI) and a progressive rise in the frequency of cardiac device implantation, there is an increased chance that patients with implanted cardiac devices require MRI examination during their lifetime. Though MRI is generally contraindicated in patients who have undergone pacemaker implantation with electronic circuits, the recent introduction of MR Conditional pacemaker allows physicians to take advantage of MRI to assess these patients during diagnosis and treatment. When MRI examinations of patients with pacemaker are requested, physicians must confirm whether the device is a conventional pacemaker or an MR Conditional pacemaker by reviewing chest radiographs or the electronic medical records (EMRs). The purpose of this study was to evaluate the utility of a deep convolutional neural network (DCNN) trained to detect pacemakers on chest radiographs and to determine the device's subclassification. The DCNN perfectly detected pacemakers on chest radiographs and the accuracy of the subclassification of pacemakers using the internal and external test datasets were 100.0% (n = 106/106) and 90.1% (n = 279/308). The DCNN can be applied to the radiologic workflow for double-checking purposes, thereby improving patient safety during MRI and preventing busy physicians from making errors.

Primary spontaneous pneumomediastinum: 237 cases in a single-center experience over a 10-year period and assessment of factors related with recurrence.

OBJECTIVE: To evaluate the precipitating factors and symptoms of primary spontaneous pneumomediastinum (PSPM) and to assess the factors related with recurrent spontaneous pneumomediastinum (RSPM). METHODS: From 2010 to 2021, 237 PSPM patients were included in this retrospective study. Clinical information including in-hospital periods, morbidity, mortality, presenting symptoms, precipitating events, smoking, and asthma history was obtained. The patients with smoking history were subdivided into "ex-smoker" or "current smoker". The severity of asthma was categorized into "mild intermittent", "mild persistent", "moderate persistent", or "severe persistent". During follow-up, patients with RSPM were classified into "recurrence" group and the others were into "no recurrence" group. Multivariate regression analysis was used to elucidate the associated factors with RSPM. RESULTS: The mean age of study patients (men: women = 222: 15) was 23.4 years and mean period of hospital stay was 7.5 days. There was no mortality and morbidity. Most frequent symptom and precipitating factor were acute chest pain (n = 211, 89.0%) and cough (n = 72, 30.4%), respectively. RSPM occurred in 11 patients (4.6%). The proportion of patients with smoking (72.8% vs. 37.1%, p = 0.010) or asthma (81.8% vs. 39.8%, p<0.001) was significantly higher in "recurrence" group than "no recurrence" group. On multivariate analysis, asthma was the only factor associated with RSPM (mild intermittent/persistent, OR = 7.092, p = 0.047; moderate persistent, OR = 8.000, p = 0.011). CONCLUSION: PSPM is a benign disease with no morbidity and mortality. Asthma may be the associated factor with RSPM; thus, despite the low rate of recurrence, patients with asthma should be informed about the chance of RSPM.

Clinical value of deep vein thrombosis density on lower-extremity CT venography: prediction of pulmonary thromboembolism.

AIM: Diagnosis of pulmonary thromboembolism (PTE) can be delayed if the signs and symptoms of patients are nonspecific. INTRODUCTION: To assess the clinical value of deep vein thrombosis (DVT) density on computed tomography (CT) venography for predicting PTE. METHOD: From 2016 to 2021, patients with DVT diagnosed on lower-extremity CT venography were included. Of these patients, those without PTE were classified into 'DVT-only group' and those with PTE were classified into the 'DVT with PTE group'. The DVT Hounsfield unit (HU) density was measured by drawing free-hand region-of-interests within the thrombus at the most proximal filling defect level. The risk factors associated with PTE were identified by using multivariate logistic regression analysis. A receiver operating characteristic (ROC) analysis was used to evaluate the value of DVT density for predicting the risk of PTE. RESULTS AND DISCUSSION: This study included 177 patients with a mean age of 41.7 ± 10.3 years (DVT-only group: 105 patients; DVT with PTE group: 72 patients). DVT density was significantly higher in DVT with the PTE group than DVT-only group (66.8HU ± 8.7 vs. 57.9HU ± 11.1, p < 0.001). The ROC analysis revealed that the area under the curve (AUC), sensitivity, and specificity for predicting the risk of PTE were 0.737, 72.2%, and 66.7%, respectively, at a DVT density cutoff of 63.0 HU. On univariate and multivariate analysis, DVT density was the only significant risk factor associated with PTE. CONCLUSION: Higher DVT density was a significant risk factor for PTE. In addition, DVT density could be a predictive factor for PTE.

Feasibility and reliability of various morphologic features on magnetic resonance imaging for iliotibial band friction syndrome.

Background: To evaluate the feasibility, inter-reader reliability, and intra-reader reliability for various morphological features reported to be related to iliotibial band friction syndrome (ITBFS) on knee magnetic resonance imaging (MRI). Methods: A total of 145 patients with a clinical diagnosis and knee MRI findings consistent with ITBFS were included in the "study group" and 232 patients without knee pathology on both physical examination and MRI were included in the "control group". Various morphologic features on knee MRI were assessed including the patella shape, patella height, lateral epicondyle anterior-posterior (AP) width, lateral epicondyle height, ITB diameter (ITB-d), and ITB area (ITB-a). Results: Patients in the study group had significantly higher lateral epicondyle height (13.9 mm vs. 12.92 mm, P = 0.003), ITB-d (2.9 mm vs. 2.0 mm, P = 0.022), and ITB-a (38.5 mm2 vs. 23.8 mm2, P < 0.001) than the control group. ITB-a showed higher area under the curve index (0.849 with 74.1% sensitivity and 72.4% specificity at a 30.3 mm2 cutoff) than ITB-d (0.710 with 70.8% sensitivity and 61.2% specificity at 2.4 mm cutoff) and lateral epicondyle height (0.776 with 72.4% sensitivity and 67.8% specificity at 13.4 mm cutoff). However, only the interreader agreement for ITB-a (intraclass correlation coefficient = 0.65) was moderate, while the agreements for other morphologic features were good or excellent. Conclusions: Lateral epicondyle height seems to be a reliable and feasible morphologic feature for diagnosis of ITBFS.

Clinical value of deep vein thrombosis density on pre-contrast and post-contrast lower-extremity CT for prediction of pulmonary thromboembolism.

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.

Newly Appearing Hepatic Lesion After Curative Surgery For Colorectal Cancer: Single-phase CT Findings Implying Metastasis.

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: The objective of this study is to evaluate CT features implying metastasis in newly appearing hepatic lesions on single-phase CT after colorectal cancer surgery. METHODS: 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 an 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.

Prevalence and neglected rate of sacroiliitis on lumbar spine CT in patients with low back pain.

OBJECTIVE: The study aims to investigate the prevalence and neglected rate of sacroiliitis on lumbar spine computed tomography (CT) in patients with low back pain. MATERIALS AND METHODS: From January 2016 to December 2020, a total of 4827 patients (mean age: 35.4 ± 9.5 years) who underwent lumbar spine CT examinations were included in this retrospective study. The CT degree of sacroiliitis in all study population were retrospectively reviewed by two radiologists. The independent sample t-test was used to compare the continuous values and chi-squared or Fisher's exact test was used to compare the categorized values. RESULTS: Sacroiliitis was identified in 514 of 4827 patients (10.6%). Patients with sacroiliitis were significantly younger than those without sacroiliitis (32.1 ± 8.9 vs. 35.8 ± 9.5 years, p < 0.001). Moreover, significantly more patients with sacroiliitis had HLA-B27 (p < 0.001) positivity and inflammatory back pain syndrome (p = 0.003) than those without sacroiliitis. Among the 514 patients, sacroiliitis was recognized on primary reading in 386 patients (75.1%) but was neglected in the remaining 128 patients (24.9%). Of the 386 patients, 371 patients were followed up, and finally, 295 patients of them (79.5%) were diagnosed with axSpA. CONCLUSION: Radiologists should pay careful and more attention to sacroiliac joint on lumbar spine CT for early diagnosis of sacroiliitis in young patients with low back pain, which could result in early diagnosis and treatment of axSpA.

Patella-patellar tendon angle in relation to the medial patellar plica syndrome, chondromalacia patella, and infrapatellar fat pad syndrome.

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.