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Purpose: To characterize brain MR imaging findings in a cohort of 58 patients with ECD and to evaluate relationship between these findings and the BRAF V600E pathogenic variant., Methods: ECD patients of any gender and ethnicity, aged 2-80 years, with biopsy-confirmed ECD were eligible to enroll in this study. Two radiologists experienced in evaluating ECD CNS disease activity reviewed MRI studies. Any disagreements were resolved by a third reader. Frequencies of observed lesions were reported. The association between the distribution of CNS lesions and the BRAF V600E pathogenic variant was evaluated using Fisher's exact test and odd ratio., Results: The brain MRI of all 58 patients with ECD revealed some form of CNS lesions, most likely due to ECD. Cortical lesions were noted in 27/58 (46.6 %) patients, cerebellar lesions in 15/58 (25.9 %) patients, brain stem lesions in 17/58 cases (29.3 %), and pituitary lesions in 10/58 (17.2 %) patients. Premature cortical atrophy was observed in 8/58 (13.8 %) patients. BRAF V600E pathogenic variant was significantly associated with cerebellar lesions (p = 0.016) and bilateral brain stem lesions (p = 0.043). A trend toward significance was noted for cerebral atrophy (p = 0.053)., Conclusion: The study provides valuable insights into the brain MRI findings in ECD and their association with the BRAF V600E pathogenic variant, particularly its association in cases with bilateral lesions. We are expanding our understanding of how ECD affects cerebral structures. Knowledge of MRI CNS lesion patterns and their association with mutations such as the BRAF variant is helpful for both prognosis and clinical management., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Published by Elsevier Inc.)

Objectives: The aim of this study was to assess the interreader reliability and per-RCC sensitivity of high-resolution photon-counting computed tomography (PCCT) in the detection and characterization of renal masses in comparison to MRI., Materials and Methods: This prospective study included 24 adult patients (mean age, 52 ± 14 years; 14 females) who underwent PCCT (using an investigational whole-body CT scanner) and abdominal MRI within a 3-month time interval and underwent surgical resection (partial or radical nephrectomy) with histopathology (n = 70 lesions). Of the 24 patients, 17 had a germline mutation and the remainder were sporadic cases. Two radiologists (R1 and R2) assessed the PCCT and corresponding MRI studies with a 3-week washout period between reviews. Readers recorded the number of lesions in each patient and graded each targeted lesion's characteristic features, dimensions, and location. Data were analyzed using a 2-sample t test, Fisher exact test, and weighted kappa., Results: In patients with von Hippel-Lindau mutation, R1 identified a similar number of lesions suspicious for neoplasm on both modalities (51 vs 50, P = 0.94), whereas R2 identified more suspicious lesions on PCCT scans as compared with MRI studies (80 vs 56, P = 0.12). R1 and R2 characterized more lesions as predominantly solid in MRIs (R1: 58/70 in MRI vs 52/70 in PCCT, P < 0.001; R2: 60/70 in MRI vs 55/70 in PCCT, P < 0.001). R1 and R2 performed similarly in detecting neoplastic lesions on PCCT and MRI studies (R1: 94% vs 90%, P = 0.5; R2: 73% vs 79%, P = 0.13)., Conclusions: The interreader reliability and per-RCC sensitivity of PCCT scans acquired on an investigational whole-body PCCT were comparable to MRI scans in detecting and characterizing renal masses., Clinical Relevance Statement: PCCT scans have comparable performance to MRI studies while allowing for improved characterization of the internal composition of lesions due to material decomposition analysis. Future generations of this imaging modality may reveal additional advantages of PCCT over MRI., Competing Interests: Conflicts of interest and sources of funding: This research was supported, in part, by the Intramural Research Program of the National Institutes of Health Clinical Center. The National Institutes of Health and Siemens Medical Solutions have a Cooperative Research and Development Agreement providing financial and material support including the photon-counting computed tomography system. One of the study co-authors (Pooyan Sahbaee) is an employee of Siemens Healthineers. The rest of the authors have nothing to declare. Authors unaffiliated with Siemens had full control over the data and information presented in this article., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

During the past decades, the role of fludeoxyglucose (FDG)-PET and hybrid PET/computed tomography (CT) has been established clinically in the diagnostic workup of a multitude of infectious and inflammatory disorders. In recent years, the fusion of MR imaging to PET has also been increasingly explored, and this may be especially useful in musculoskeletal and gastrointestinal inflammatory diseases due to exceptional soft tissue contrast and reduced radiation dose. This article outlines the current potential for hybrid molecular imaging in the musculoskeletal system and the gastrointestinal tract with special focus on the potential for fused PET/CT/MR imaging., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Detecting inflammation is among the most important aims of medical imaging. Inflammatory process involves immune system activity and local tissue response. The role of PET with fludeoxyglucose F 18 has been expanded. Systemic vasculitides and cardiopulmonary inflammatory disorders constitute a wide range of diseases with multisystemic manifestations. PET with fludeoxyglucose F 18 is useful in their diagnosis, assessment, and follow-up. This article provides an overview of the current status and potentials of hybrid molecular imaging in evaluating cardiopulmonary and vascular inflammatory diseases focusing on the potential for PET with fludeoxyglucose F 18/MR imaging and PET/CT scans., (Published by Elsevier Inc.)

18F-Fluorodeoxyglucose PET has been used to evaluate a wide array of inflammatory and neoplastic pathologies. MR imaging has great soft tissue resolution and high accuracy for detection of edema. Combining PET with MR imaging offers substantial advantages in musculoskeletal imaging. Specifically, evidence demonstrates the potential of imaging of bone marrow, soft tissue, and synovia by PET/MR imaging. Because of inherent limitations of 1 H-MR to image cortical bone, there are some challenges; however, the use of 18F-sodium fluoride for PET/MR imaging could change the landscape. This article reviews the literature regarding PET/MR imaging in identification and management of many musculoskeletal diseases., Competing Interests: Disclosure No conflict of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objectives: To use magnetic resonance imaging (MRI) and computed tomography (CT) to define abdominal involvement in Erdheim-Chester disease (ECD), and to investigate the association between these findings and the BRAF V600E mutation., Methods: This prospective study was performed on 61 ECD patients (46 men). The MRI and CT imaging studies were reviewed independently by two experienced radiologists. The association between BRAF V600E mutation and imaging findings was analysed using Fisher's exact test, and odds ratios with 95% confidence intervals., Results: Perinephric infiltration was the most common finding (67%), followed by involvement of proximal ureters (61%). In 56% of cases, infiltration extended to the renal sinuses, and in 38% caused hydronephrosis. Adrenal gland infiltration was present in 48% of patients. Infiltration of renal artery (49%) and aorta (43%) were the most common vascular findings, followed by sheathing of celiac, superior mesenteric artery (SMA) or inferior mesenteric artery (IMA) (23%). The BRAF V600E mutation was positive in 53% of patients with interpretable BRAF sequencing. There was a statistically significant association between this mutation and perinephric infiltration (p = 0.003), renal sinus involvement (p < 0.001), infiltration of proximal ureters (p < 0.001), hydronephrosis (p < 0.001), adrenal gland involvement (p < 0.001), periaortic infiltration (p = 0.03), sheathing or stenosis of renal artery (p < 0.001) and sheathing of other aortic branches (p = 0.04)., Conclusions: Renal and vascular structures are the most commonly affected abdominal organs in ECD patients. Some of these findings have significant positive association with the BRAF V600E mutation., Key Points: • Abdominal imaging plays a crucial role in management of Erdheim-Chester disease. • Significant associations exist between BRAF V600E mutation and several abdominal imaging findings. • Considering several associations, evaluating BRAF V600E mutation status is recommended in ECD patients.

To investigate the diagnostic performance of a deep convolutional neural network for differentiation of clear cell renal cell carcinoma (ccRCC) from renal oncocytoma. In this retrospective study, 74 patients (49 male, mean age 59.3) with 243 renal masses (203 ccRCC and 40 oncocytoma) that had undergone MR imaging 6 months prior to pathologic confirmation of the lesions were included. Segmentation using seed placement and bounding box selection was used to extract the lesion patches from T2-WI, and T1-WI pre-contrast, post-contrast arterial and venous phases. Then, a deep convolutional neural network (AlexNet) was fine-tuned to distinguish the ccRCC from oncocytoma. Five-fold cross validation was used to evaluate the AI algorithm performance. A subset of 80 lesions (40 ccRCC, 40 oncocytoma) were randomly selected to be classified by two radiologists and their performance was compared to the AI algorithm. Intra-class correlation coefficient was calculated using the Shrout-Fleiss method. Overall accuracy of the AI system was 91% for differentiation of ccRCC from oncocytoma with an area under the curve of 0.9. For the observer study on 80 randomly selected lesions, there was moderate agreement between the two radiologists and AI algorithm. In the comparison sub-dataset, classification accuracies were 81%, 78%, and 70% for AI, radiologist 1, and radiologist 2, respectively. The developed AI system in this study showed high diagnostic performance in differentiation of ccRCC versus oncocytoma on multi-phasic MRIs. • A robust radiologic method to accurately differentiate ccRCC and oncocytoma is not available. • The AI system in the present study showed high diagnostic performance in differentiation of ccRCC and oncocytoma on MRI. • There was moderate agreement between the two radiologists and AI algorithm for the subset observer study. [ABSTRACT FROM AUTHOR]

To retrospectively investigate the radiological presentations of HLRCC-associated renal tumors to facilitate accurate lesion characterization and compare these presentations with simple cysts and characteristics of other subtypes of renal cell carcinoma (RCC) as reported in the literature. The MRI and CT imaging characteristics of 39 pathologically confirmed lesions from 30 patients (20 male, 10 female) with HLRCC syndrome were evaluated by two radiologists. Patients had an average age at diagnosis of 43.8 ± 13.1 years. Lesion characteristics including laterality, homogeneity, diameter (cm), nodularity, septations, T1 and T2 signal intensity, enhancement, and restricted diffusion were recorded. Imaging characteristics of the lesions were further compared to characteristics of benign simple cysts surgically removed at the same time point. The examined lesions had a mean diameter of 5.06 ± 3.80 cm, an average growth rate of 2.91 × 10−3 cm/day and an estimated annual growth rate of 1.06 cm/year. 50% of lesions demonstrated nodularity, 65% were mostly T2-hyperintense, 83% demonstrated restricted diffusion in solid portions of the lesions, and 65% had well-defined margins. 76% of patients demonstrated extra-renal manifestations, 53% lymphadenopathy, and 43% distant metastasis. Our analysis confirmed that while HLRCC-associated renal lesions demonstrate diversity in imaging presentations, the majority are unilateral and solitary, T2-hyperintense, heterogeneous with well-defined margins, and frequently demonstrate restricted diffusion and nodularity. • HLRCC-associated renal lesions demonstrated an average annual growth rate of 1.06 cm/year. • Majority of lesions had well-defined margins (65%) and were T2-hyperintense (65%). • Lesions demonstrated high rates of metastasis and lymph node involvement. [ABSTRACT FROM AUTHOR]

Acute pancreatitis is a condition marked by inflammation of the pancreas and surrounding tissues. While the majority of cases of acute pancreatitis are mild, a minority of severe cases are the primary contributors to the morbidity and mortality attributed to this condition. Retroperitoneal morphologic changes can be detected by utilization of various imaging modalities, and their accurate evaluation is crucial for effective management. Acute pancreatitis is commonly diagnosed using computed tomography (CT). However, there are certain clinical scenarios where magnetic resonance imaging (MRI) may have superiority over CT. In particular, MRI is useful in cases where patients cannot receive iodinated CT contrast, or where there is a need to investigate the underlying cause of acute pancreatitis. Additionally, MRI can be utilized to evaluate ductal disconnection and guide interventions for necrotic collections. The unique features of MRI can be particularly useful, including its ability to provide superior contrast resolution and to offer greater functional information through techniques such as diffusion-weighted imaging. The aim of this review is to discuss the MRI assessment of individuals with acute pancreatitis. Additionally, the recent advances in MRI for evaluation of acute pancreatitis will also be introduced. • The high sensitivity of MRI is instrumental in detecting early inflammatory changes and parenchymal damage in acute pancreatitis. • Without the need for iodinated contrast agents, MRI identifies necrotic pancreatic tissue, reducing potential complications. • In addition to parenchymal evaluation, MRI provides a detailed examination of the pancreaticoobiliary ductal system. • MRI is superior at identifying solid contents within necrotizing collections, facilitating accurate diagnosis and treatment planning. • MRI advances have improved scan times and reduced artifacts, enabling use in critically ill patients with acute pancreatitis. [ABSTRACT FROM AUTHOR]

Objectives: To use magnetic resonance imaging (MRI) and computed tomography (CT) to define abdominal involvement in Erdheim-Chester disease (ECD), and to investigate the association between these findings and the BRAFV600E mutation.Methods: This prospective study was performed on 61 ECD patients (46 men). The MRI and CT imaging studies were reviewed independently by two experienced radiologists. The association between BRAFV600E mutation and imaging findings was analysed using Fisher's exact test, and odds ratios with 95% confidence intervals.Results: Perinephric infiltration was the most common finding (67%), followed by involvement of proximal ureters (61%). In 56% of cases, infiltration extended to the renal sinuses, and in 38% caused hydronephrosis. Adrenal gland infiltration was present in 48% of patients. Infiltration of renal artery (49%) and aorta (43%) were the most common vascular findings, followed by sheathing of celiac, superior mesenteric artery (SMA) or inferior mesenteric artery (IMA) (23%). The BRAFV600E mutation was positive in 53% of patients with interpretable BRAF sequencing. There was a statistically significant association between this mutation and perinephric infiltration (p = 0.003), renal sinus involvement (p < 0.001), infiltration of proximal ureters (p < 0.001), hydronephrosis (p < 0.001), adrenal gland involvement (p < 0.001), periaortic infiltration (p = 0.03), sheathing or stenosis of renal artery (p < 0.001) and sheathing of other aortic branches (p = 0.04).Conclusions: Renal and vascular structures are the most commonly affected abdominal organs in ECD patients. Some of these findings have significant positive association with the BRAFV600E mutation.Key Points: • Abdominal imaging plays a crucial role in management of Erdheim-Chester disease. • Significant associations exist between BRAF V600E mutation and several abdominal imaging findings. • Considering several associations, evaluating BRAFV600E mutation status is recommended in ECD patients. [ABSTRACT FROM AUTHOR]