Comparison of the efficacy of the gadoxetic acid MRI-derived relative enhancement index (REI) and functional liver imaging score (FLIS) in predicting liver function: validation with Albumin-Bilirubin (ALBI) grade.

PURPOSE: This study compared the predictive performance of the relative enhancement index (REI) derived from gadoxetic acid (GA)-enhanced MRI with that of the functional liver imaging score (FLIS) in estimating liver function among patients with chronic liver disease (CLD) or liver cirrhosis (LC) by validating them with the albumin-bilirubin (ALBI) grade. MATERIALS AND METHODS: We retrospectively examined 166 patients (79 women, 87 men; 57.4 years) who were diagnosed with LC or CLD and underwent GA-enhanced MRI between August 2020 and September 2023. The enhancement ratio (ER) is calculated using the formula: ER = [hepatobiliary phase liver signal (SI HBP20)-precontrast liver signal (SI pre)]/SI pre. The REI is calculated using the formula: REI = Liver Volume (LV) × ER. FLIS was assigned from the sum of three HBP image features, each scored between 0 and 2: liver parenchymal enhancement, biliary contrast excretion, and portal vein sign. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff values of ER, REI, and FLIS in differentiating between ALBI grades. The area under the curve (AUC), accuracy, sensitivity, and specificity were calculated for REI and FLIS to distinguish the ALBI grades. Spearman's rank correlation was used to evaluate the ER, REI, and FLIS correlations between the ALBI grades. To evaluate inter-reader reliability for LV, ER, REI, and FLIS, intraclass correlation coefficient (ICC) was used. RESULTS: ROC curve analysis showed that the optimal cutoff value of REI for predicting ALBI Grade 1 was 899-905 for readers 1 and 2 and 461-477 for ALBI Grade 3, respectively. REI performed best in predicting ALBI Grade 1, achieving an accuracy range of 94%-92.2%, sensitivity of 94.9%-94.1%, and specificity of 91.7%-87.5% for readers 1 and 2, respectively. All parameters showed high accuracy in distinguishing ALBI Grade 3 from other grades. However, REI outperformed the others, showing an accuracy range of 98.8%-97.6%, sensitivity of 94.4%-94.4%, and specificity of 99.3%-98% for readers 1 and 2, respectively. REI showed the best and very strong correlation with ALBI for both readers. CONCLUSION: REI showed a very strong correlation with the ALBI grades for assessing liver function. It outperformed FLIS in predicting the ALBI grades, indicating its potential as a radiologic tool comparable to or better than FLIS in predicting liver function, especially given its dependence on liver volume.

Peroneal artery injury potential due to different syndesmosis screw placement options: a simulation study with lower extremity computed tomography angiography.

INTRODUCTION: The aim of this study is to assess the risk of peroneal artery injury of hardware placement at the fixation of syndesmotic injuries. MATERIALS AND METHODS: The lower extremity computed tomography angiography was used to design the study. The syndesmosis screw placement range was simulated every 0.5 cm, from 0.5 to 5 cm proximal to the ankle joint. The screw axes were drawn as 20°, 30° or individual angle according to the femoral epicondylar axis. The proximity between the screw axis and the peroneal artery was measured in millimeters. Potential peroneal artery injury was noted if the distance between the peroneal artery to the axis of the simulated screw was within the outer shaft radius of the simulated screw. The Pearson chi-square test was used and a p-value < 0.05 was considered significant. RESULTS: The potential for injury to the peroneal artery increased as the syndesmosis screw level rose proximally from the ankle joint level or as the diameter of the syndesmosis screw increasds. In terms of syndesmosis screw trajection, the lowest risk of injury was observed with the syndesmosis screw angle of 20°. Simulations with a screw diameter of 3.5 mm exhibited the least potential for peroneal artery injury. CONCLUSION: Thanks to this radiological anatomy simulation study, we believe that we have increased the awareness of the peroneal artery potential in syndesmosis screw application. Each syndesmosis screw placement option may have different potential for injury to the peroneal artery. To decrease the peroneal artery injury potential, we recommend the followings. If individual syndesmosis screw angle trajection can be measured, place the screw 1.5 cm proximal to the ankle joint using a 3.5 mm screw shaft. If not, fix it with 30° trajection regardless of the screw diameter at the same level. If the most important issue is the peroneal artery circulation, use the screw level up to 1 cm proximal to the ankle joint regardless of the screw angle trajection and screw diameter.

Evaluation of qualitative and quantitative imaging features of hepatic hemangiomas with and without pseudo-washout sign on gadoxetic acid-enhanced MRI: a descriptive and comparative study.

BACKGROUND: Hepatic hemangiomas are the most common benign liver tumors. It is important to know the imaging features of hemangiomas on gadoxetic acid (GA)-enhanced magnetic resonance imaging (MRI). PURPOSE: To evaluate the qualitative and quantitative imaging features of hemangiomas on GA-enhanced MRI, and to compare imaging features of hemangiomas with and without pseudo-washout sign (PWS). MATERIAL AND METHODS: We retrospectively included 93 cases of hemangioma that underwent GA-enhanced MRI. The presence of an enhancement pattern in the arterial phase (AP) and PWSs in the transitional phase (TP) were evaluated. Signal-to-norm ratios (SINorm) of hemangiomas, liver parenchyma, and portal vein (PV) as well as contrast-to-norm ratio (CNorm) were assessed. Additionally, hemangiomas with and without PWSs were defined as two separate subgroups, and imaging features were compared. RESULTS: Of the 93 cases of hemangiomas, 49 (52.6%) had PWSs in the TP. The mean SINorms of hemangiomas showed the highest value in the AP (P < 0.05). The mean CNorms showed positive values in the AP, and gradually decreased (P < 0.05). Hemangiomas with PWSs were significantly rapidly enhanced and smaller in size (P < 0.05), and the mean SINorms was lower in the TP (P = 0.023). While the mean CNorms showed a significant difference in the AP between subgroups (P < 0.001), the enhancement pattern was equal to that of the PV. CONCLUSION: When evaluating GA-enhanced MRI, radiologists should utilize quantitative measures in addition to qualitative assessment and should be aware that SI matching with PV in all phases can be a distinguishing finding in the diagnosis of hemangioma.

Nerve Root Compression Due to Contralateral Compensatory Hypertrophy: A Rare Case of Vertebral Artery Thrombosis.

In the patient who complained of dizziness, thrombus was observed in the right vertebral artery. Compression was detected in the nerve root due to compensatory hypertrophy in the left vertebral artery. In conclusion, in cases of unilateral vertebral artery thrombosis, should be aware of the pathologies that may develop in adjacent structures due to compensatory hypertrophy. Teaching Point: An occluded vertebral artery (VA) can cause contralateral VA hypertrophy, which can cause various pathologies including nerve root compression.

Comparison of the diagnostic performance of biparametric and multiparametric MRI in detecting muscle invasion of bladder cancer located at the ureteral orifice.

PURPOSE: To assess the diagnostic performance of biparametric magnetic resonance imaging (bp-MRI) in predicting detrusor muscle invasion for bladder cancer (BC) located at the ureteral orifice by comparing it with the Vesical Imaging Reporting and Data System (VI-RADS) system based on multiparametric MRI (mp-MRI). METHODS: Patients with histopathologically proven BC located at the ureteral orifice from December 2019 to November 2022 were analyzed retrospectively. Two sets, bp-MRI (set 1) and mp-MRI (set 2), were formed from the images. Both sets were evaluated independent of histopathology by three radiologists with different levels of experience in abdominal radiology. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic performance of VI-RADS in the prediction of muscle invasion. The intraclass correlation coefficient (ICC) was used to evaluate inter-reader agreement. RESULTS: Of 68 patients with BCs located at the ureteral orifice, 50 (48 males, median age: 72 years) met the study criteria. Out of the 50 patients, 36 had non-muscle invasive BC (pTa-T1) and 14 had muscle invasive BC (MIBC) (pT2-T4). In the comparison of VI-RADS categories with histopathologic data for MIBC detection, the area under the curve of the ROC analysis for the bp- and mp-MRI protocol was 1.000-0.986 for reader 1, 0.893-0.901 for reader 2, and 0.808-0.865 for reader 3. There was no statistically significant difference in predicting detrusor muscle invasion with the bp- and mp-MRI-based on VI-RADS categories for all readers (p = 0.126, 0.203, and 0.322, respectively). The ICCs between all the readers showed excellent agreement and were similar for both protocols. CONCLUSION: The bp-MRI consisting of DWI and T2-WI can be used as an alternative to the mp-MRI in predicting detrusor muscle invasion for BCs located at the ureteral orifice; however, less experienced readers should exercise caution.

Intrascrotal Extratesticular Schwannoma: A Rare Cause of Scrotal Mass.

BACKGROUND: Schwannoma, also known as neurinoma, is the most common tumor of the peripheral nerves. Intrascrotal extratesticular schwannoma, which is not associated with schwannomatosis and neurofibromatosis-2, is a very rare entity, and few cases have been reported in the literature. In this paper, we have reported a case of extratesticular schwannoma, an extremely rare cause of scrotal mass, with ultrasound (US) and magnetic resonance imaging (MRI) findings. CASE REPORT: A 22-year-old male presented with painless left scrotal swelling. Scrotal US showed an extra-testicular heterogeneous hypoechoic mass with the lobulated contour in the inferior part of the scrotum. Scrotal MRI demonstrated well-defined extratesticular mass, which showed heterogeneous hypointense T2-weighted images compared to testis parenchyma. On contrast-enhanced images, the mass showed mild-to-moderate enhancement. The patient underwent surgery with the preliminary diagnosis of benign intrascrotal extratesticular mass. The lesion was removed with preservation of the testicles by urologists, and the final diagnosis was made as scrotal schwannoma by histological and immunohistochemical examination. CONCLUSION: Although there is no specific imaging finding of scrotal schwannoma, MRI can be used as a guide to surgery by helping to accurately determine whether the lesion is intra- or extratesticular. In addition, radiologists and urologists should keep schwannoma in mind in the differential diagnosis in the presence of an intrascrotal extratesticular mass.

Determining the efficacy of functional liver imaging score (FLIS) obtained from gadoxetic acid-enhanced MRI in patients with chronic liver disease and liver cirrhosis: the relationship between Albumin-Bilirubin (ALBI) grade and FLIS.

PURPOSE: (1) To evaluate the efficacy of functional liver imaging score (FLIS) in predicting liver function on gadoxetic acid-enhanced MRI in patients with chronic liver disease (CLD) or liver cirrhosis (LC) and its relationship with ALBI grade. (2) To assess the intra-reader reliability and interreader agreement of readers with different levels of experience in abdominal imaging of FLIS. METHODS: We retrospectively included 131 patients (70 men, 61 women; mean ± SD, 53.7 ± 14.6 years) with CLD and LC who underwent GA-enhanced MRI between November 2019 and March 2022. FLIS was assigned as a result of the sum of three hepatobiliary phase (HBP) images features, each scored 0-2: liver parenchymal enhancement, biliary contrast excretion, and portal vein sign. FLIS was calculated using HPB images independently by three radiologists with different experience. In addition, 50 randomly selected patients were reviewed a second time by a reader to assess intra-reader reliability. Patients were divided into the following three groups according to the albumin-bilirubin (ALBI) grade: ALBI grade 1, 2, and 3. We evaluated the correlation between ALBI grade and both FLIS and its parameters using Spearman's rank correlation for each reader. Receiver operating characteristic (ROC) curve analysis was performed to show the optimal cut-off value of FLIS to distinguish between ALBI grades. Intra-reader reliability and inter-reader agreement were evaluated by intraclass correlation coefficient (ICC). RESULTS: FLIS and three FLIS parameters showed very strong correlation with ALBI grade for each readers (r = - 0.843 to 0.976, - 0.831 to 0.962, and - 0.819 to 0.902, respectively). ROC curve analysis showed that FLIS ≥ 5 was the optimal cutoff for prediction of ALBI grade 1 for each readers (sensitivity, 83.7% to 95.4%; specificity, 82.6% to 87%; accuracy, 88.6% to 93.6% and area under the curve (AUC), 0.882 to 0.917), and FLIS ≤ 3 was the optimal cutoff for distinguish ALBI grade 3 from other grades for each readers (sensitivity, 100%; specificity, 95.2% to 96%; accuracy, 95.4% to 96.2% and AUC, 0.974 to 0.994). Intra-reader reliability (ICC = 0.95; 95% CI 0.93-0.96) and inter-reader agreement (ICC = 0.85 to 0.90; 95% CI 0.82-0.97) for FLIS were excellent. CONCLUSION: FLIS showed a very correlation with hepatic function level and can stratify the ALBI grades. This feature has demonstrated the potential of FLIS to be excellent radiological tools for predicting of liver function of CLD and LC patients in clinical practice. Also, the excellent agreement of FLIS among readers with different levels of experience indicates that it can be used with high accuracy and reproducibility regardless of experience.