UNASSIGNED: The purpose of our study was to investigate the role of different magnetic resonance imaging (MRI) parameters in the characterization of adrenal masses.
UNASSIGNED: A total of 150 patients who presented with 186 adrenal tumors were retrospectively evaluated in this study. Final patient cohort consisted of 17 pheochromocytomas, 3 adrenocortical carcinomas, 24 metastases, 31 lipid-poor adenomas and 111 lipid-rich adenomas. We carried out a visual assessment on FSE (Fast spin echo)T2 weighted images and also calculated T2 signal intensity ratio of all adrenal masses and also performed a qualitative assessment on chemical shift imaging (CSI) together with quantitative calculation using Adrenal to spleen signal intensity (si) ratio and Adrenal si index formulas. On dynamic contrast-enhanced sequences, visual assessment based on enhancement patterns on late-arterial phase images was performed and also mean signal intensity measurements were carried out. All examinations were interpreted by two abdominal radiologists in consensus who were blinded to the clinical and pathological findings. Statistical analysis was performed.
UNASSIGNED: On FSE T2 weighted imaging, isointense to liver and slightly hyperintense than liver was found higher in benign cases, however, in malignant cases moderately and strikingly hyperintense than liver was higher than in benign cases (p=0.001, p<0.01). There was a statistically significant difference between the T2 signal intensity ratio values of adrenal tumor groups (p=0.001, p<0.01). In lipid-rich and lipid-poor adenoma groups, T2 signal intensity ratio values was significantly lower than in pheochromocytoma and metastasis cases. In malignant group, T2 signal intensity ratio values were found statistically significantly higher than in the benign group (p=0.001, p<0.01). There was a statistically significant difference between CSI visual assessment of adrenal tumor groups (p=0.001, p<0.01). Although moderate and significant signal intensity loss was usually detected in lipid-rich adenoma group, never detected in other tumor groups. There was also a statistically significant difference between benign and malignant adrenal tumor groups (p=0.001, p<0.01). In the malignant group, Adrenal to spleen si ratio values were found significantly higher whereas, Adrenal si index values were significantly lower compared to benign tumors (p=0.001, p<0.01). Based on malignancy, there was a statistically significant difference between adrenal tumor groups (p=0.001, p<0.01). Although capillary blush and homogenous type enhancement were more common in benign cases than in malignant ones, peripheral-patchy and strikingly capillary blush type enhancement was more frequent in malignant tumors. Based on malignancy, mean arterial signal intensity values of malignant tumors were statistically higher than benign tumors (p=0.001; p<0.01).
UNASSIGNED: Dynamic contrast-enhanced MRI protocol including CSI aids in the characterization of indeterminate adrenal masses. Herein, the combined use of qualitative and quantitative parameters enables more tumors to be recognized that otherwise would be indeterminate.

Neurolymphomatosis (NL) is a rare complication of non-Hodgkin\'s lymphoma, characterized by the infiltration of lymphoma cells into the peripheral nerves. A 54-year-old woman initially presented with right facial palsy without any other significant symptoms and was diagnosed with Bell\'s palsy. Despite initial improvement, her condition recurred, prompting further evaluation. Magnetic resonance imaging (MRI) revealed contrast enhancement from the tympanic segment to the surface of the masseter muscle along the right facial nerve and an adjacent mass lesion. Biopsy of the mass revealed a diagnosis of T-cell/histiocyte-rich large B-cell lymphoma. Chemotherapy resulted in complete resolution of facial palsy. Follow-up MRI confirmed the absence of contrast enhancement along the facial nerve. Facial palsy was considered to be caused by NL. This case was classified as that of primary NL because the facial palsy was the first manifestation of a hematologic malignancy. Recurrent facial palsy, which is atypical in Bell\'s palsy, led to further evaluation with MRI, which finally resulted in the diagnosis of malignant lymphoma. In cases of recurrent facial palsy, clinicians should consider various diagnoses, including that of NL, and advocate early imaging tests and biopsy, if possible, for accurate diagnosis and improved outcomes.

Contrast-enhanced magnetic resonance imaging (CE-MRI) is a pivotal tool for global disease diagnosis and management. Since its clinical availability in 2009, the off-label use of ferumoxytol for ferumoxytol-enhanced MRI (FE-MRI) has significantly reshaped CE-MRI practices. Unlike MRI that is enhanced by gadolinium-based contrast agents, FE-MRI offers advantages such as reduced contrast agent dosage, extended imaging windows, no nephrotoxicity, higher MRI time efficiency and the capability for molecular imaging. As a leading superparamagnetic iron oxide contrast agent, ferumoxytol is heralded as the next generation of contrast agents. This review delineates the pivotal clinical applications and inherent technical superiority of FE-MRI, providing an avant-garde medical-engineering interdisciplinary lens, thus bridging the gap between clinical demands and engineering innovations. Concurrently, we spotlight the emerging imaging themes and new technical breakthroughs. Lastly, we share our own insights on the potential trajectory of FE-MRI, shedding light on its future within the medical imaging realm.

Idiopathic bilateral facial nerve palsy is a rare condition and presents a diagnostic and prognostic challenge. Specifically, when bilateral nerves are damaged, it is difficult to predict the prognosis. We showcase the usefulness of contrast-enhanced magnetic resonance imaging (MRI) by providing information about localization and severity of degeneration of facial nerve. A 70-year-old Japanese man presented with bilateral simultaneous facial nerve palsy of House-Brackmann Grade VI on both sides. Contrast-enhanced MRI revealed bilateral intensity enhancement of intratemporal facial nerves. The signal intensity was higher on the left side than on the right side. Facial nerve decompression was performed on the left side. The left facial nerve palsy was finally improved eight months after the onset, while the right side was improved just under two months after the onset. Contrast-enhanced MRI for facial nerve palsy can provide valuable information for the evaluation of damaged facial nerves. In our patient\'s case, it was useful as a prognostic predictor of bilateral facial nerve palsy.

OBJECTIVE: The objective was to evaluate outcomes of mammographic architectural distortion (AD) with and without MRI and US correlates.
METHODS: A retrospective review of unexplained mammographic AD with subsequent MRI from January 1, 2007 to September 30, 2017 was performed using a reader-based study design. Mammographic, MRI, and US features and outcomes were documented. Truth was based on biopsy results or minimum two-year imaging follow-up. Measures of diagnostic accuracy were calculated.
RESULTS: Fifty-six cases of AD were included: 29 (51.8%) detected on 2D mammogram and 27 (48.2%) detected on digital breast tomosynthesis. Of 35.7% (20/56) with MRI correlate, 40.0% (8/20) were enhancing masses, 55.0% (11/20) were non-mass enhancement (NME), and 5.0% (1/20) were nonenhancing AD. Of eight enhancing masses, 75.0% (6/8) were invasive cancers, and 25.0% (2/8) were high-risk lesions. Of 11 NME, 18.2% (2/11) were ductal carcinoma in situ, 36.4% (4/11) were high-risk lesions, and 45.4% (5/11) were benign. Of 64.3% (36/56) without MRI correlate, 94.4% (34/36) were benign by pathology or follow-up, one (2.8%, 1/36) was a 4-mm focus of invasive cancer with US correlate, and one (1/36, 2.8%) was a high-risk lesion. Of cases without MRI and US correlates, one (3.0%, 1/33) was a high-risk lesion and 97.0% (32/33) were benign. The negative predictive value of mammographic AD without MRI correlate was 97.2% (35/36) and without both MRI and US correlates was 100.0% (33/33).
CONCLUSIONS: Mammographic AD without MRI or US correlate was not cancer in our small cohort and follow-up could be considered, reducing interventions.

UNASSIGNED: Diagnosis of Menière\'s disease (MD) relies on subjective factors and the patients diagnosed with MD may have heterogeneous pathophysiologies. This study aims to stratify MD patients using two objective data, nystagmus videos and contrast-enhanced magnetic resonance imaging (CE-MRI).
UNASSIGNED: This is a retrospective cross-sectional study. According to the Japan Society for Equilibrium Research criteria (c-JSER), adults diagnosed with definite MD and who obtained videos recorded by portable nystagmus recorder immediately following vertigo attacks and underwent CE-MRI of the inner ear were included (ss = 91). Patients who obtained no nystagmus videos, who had undergone sac surgery, and those with long examination intervals were excluded (n = 40).
UNASSIGNED: The gender of the subjects was 22 males and 29 females. The age range was 20-82 y, with a median of 54 y. Endolymphatic hydrops (EH) were observed on CE-MRI in 84% (43 patients). Thirty-one patients had unilateral EH. All of them demonstrated EH on the side of the presence of cochlear symptoms. The number of patients who had both nystagmus and EH was 38. Five patients only showed EH and 5 patients only exhibited nystagmus, while 3 patients did not have either. Of the 43 nystagmus records, 32 showed irritative nystagmus immediately after the vertigo episode. The direction of nystagmus later reversed in 44% of cases over 24 h.
UNASSIGNED: Patients were stratified into subgroups based on the presence or absence of EH and nystagmus. The side with cochlear symptoms was consistent with EH. The c-JSER allows for the diagnosis of early-stage MD patients, and it can be used to treat early MD and preserve hearing; however, this approach may also include patients with different pathologies.

Testicular Leydig cell tumor (LCT) is a rare subtype of testicular neoplasms that occurs in the interstitial tissue of testes, accounting for 1-3% of total testicular masses removed annually. We report a case of 70-year-old man diagnosed as testicular LCT. This report demonstrates a testicular LCT with intratumoral and non-tumorous testicular parenchymal enhancement in the affected testis, which should be considered characteristic findings of LCT.
Ultrasonography showed a hypoechoic mass. On magnetic resonance imaging, the tumor showed low signal intensity comparable to the surrounding testicular tissue on T1-weighted images (T1WI) and low signal intensity on T2-weighted images (T2WI). On gadolinium contrast-enhanced T1WI (CE-T1WI), the tumor showed a rapid and marked wash-in and subsequent prolonged washout. The spared, non-tumorous testicular parenchyma showed slow and progressive enhancement in the early phase, which was as strong as or stronger than that of the mass in the delayed phase. The patient underwent right orchiectomy.
Pathologically, the tumor was diagnosed as a testicular Leydig cell tumor (LCT). Leydig cell proliferation was observed with well-developed microvessels, atrophy of the seminiferous tubules, and stromal edema in the non-tumorous testicular parenchyma. Leydig cells in the non-tumorous parenchyma were positive for estrogen receptors.
Since the contrast findings in the non-tumorous testicular parenchymal region on CE-T1WI likely match the histopathological features of LCT, our case suggests that the presence of non-tumorous testicular parenchymal enhancement on imaging might indicate a diagnosis of LCT.

Gallium-68 (68Ga)-labeled somatostatin analog (SSA) PET imaging has been widely used in clinical practice of neuroendocrine neoplasms (NENs). Compared with 68Ga, 18F has a great practical and economic advantage. Although a few studies have shown the characteristics of [18F] AlF-NOTA-octreotide ([18F]-OC) in healthy volunteers and small NEN patient groups, its clinical value needs further investigation. Herein, this retrospective study aimed to evaluate the diagnostic accuracy of [18F]-OC PET/CT in detecting NENs, as well as to compare it with contrast-enhanced CT/MRI.
We retrospectively reviewed the data of 93 patients who had undergone [18F]-OC PET/CT and CT or MRI scans. Of these patients, there were 45 patients with suspected NENs for diagnostic evaluation, and 48 patients with pathologically confirmed NENs for detecting metastasis or recurrence. [18F]-OC PET/CT images were evaluated visually and semi-quantitatively by measuring maximum standardized uptake value of tumor (SUVmax), tumor-to-background SUVmax ratio (TBR), and SUVmax of hypophysis (SUVhypophysis). A total of 276 suspected NEN lesions were found in these 93 patients. The results of histopathology or radiographic follow-up served as the reference standard for the final diagnosis.
Forty-five patients with suspected NENs were confirmed by histopathological examination via resection or biopsy. [18F]-OC PET/CT showed high radiotracer uptake in the lesions of G1-G3 NENs. [18F]-OC PET/CT showed superior performance with 96.3% of sensitivity, 77.8% of specificity, and 88.9% of accuracy in diagnosing NENs compared to CT/MRI. When cutoffs of SUVmax, TBR, and SUVhypophysis were 8.3, 3.1, and 15.4, [18F]-OC PET/CT had the best equilibrium between sensitivity and specificity for differentiating NEN from non-NEN lesions. For a total of 276 suspected NEN lesions, the sensitivity, specificity, and accuracy of [18F]-OC PET/CT for diagnosis of NENs were 90.5%, 82.1%, and 88.8%, respectively, and were higher than those of CT and MRI. G1 and G2 NENs had higher TBR and lower CT enhancement intensity than G3. The SUVmax and TBR had a positive correlation with CT enhancement intensity in G2 rather than in G1 or G3.
[18F]-OC PET/CT is a promising imaging modality for initial diagnosis and detecting metastasis or postoperative recurrence in NENs.

The non-perfused volume (NPV) is an important indicator of treatment success immediately after prostate ablation. However, visualization of the NPV first requires an injection of MRI contrast agents into the bloodstream, which has many downsides. Purpose of this study was to develop a deep learning model capable of predicting the NPV immediately after prostate ablation therapy without the need for MRI contrast agents. A modified 2D deep learning UNet model was developed to predict the post-treatment NPV. MRI imaging data from 95 patients who had previously undergone prostate ablation therapy for treatment of localized prostate cancer were used to train, validate, and test the model. Model inputs were T1/T2-weighted and thermometry MRI images, which were always acquired without any MRI contrast agents and prior to the final NPV image on treatment-day. Model output was the predicted NPV. Model accuracy was assessed using the Dice-Similarity Coefficient (DSC) by comparing the predicted to ground truth NPV. A radiologist also performed a qualitative assessment of NPV. Mean (std) DSC score for predicted NPV was 85% ± 8.1% compared to ground truth. Model performance was significantly better for slices with larger prostate radii (> 24 mm) and for whole-gland rather than partial ablation slices. The predicted NPV was indistinguishable from ground truth for 31% of images. Feasibility of predicting NPV using a UNet model without MRI contrast agents was clearly established. If developed further, this could improve patient treatment outcomes and could obviate the need for contrast agents altogether. Trial Registration Numbers Three studies were used to populate the data: NCT02766543, NCT03814252 and NCT03350529.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s13534-022-00250-y.

OBJECTIVE: The purpose of this study was to assess if radiologists assisted by deep learning (DL) algorithms can achieve diagnostic accuracy comparable to that of pre-surgical biopsies in benign-malignant differentiation of musculoskeletal tumors (MST).
METHODS: We first conducted a systematic review of literature to get the respective overall diagnostic accuracies of fine-needle aspiration biopsy (FNAB) and core needle biopsy (CNB) in differentiating between benign and malignant MST, by synthesizing data from the articles meeting our inclusion criteria. To compared against the accuracies reported in literature, we then invited 4 radiologists, respectively with 2 (A), 6 (B), 7 (C), and 33 (D) years of experience in interpreting musculoskeletal MRI to perform diagnostic tests on our own dataset (n = 62), with and without assistance of a previously developed DL algorithm. The gold standard for benign-malignant differentiation was histopathologic confirmation or clinical/radiographic follow-up.
RESULTS: For FNAB, a meta-analysis containing 4604 samples met the inclusion criteria, with the overall diagnostic accuracy reported to be 0.77. For CNB, an overall accuracy of 0.86 was derived by synthesizing results from 7 original research articles containing a total of 587 samples. On our internal MST dataset, the invited radiologists, respectively, achieved diagnostic accuracies of 0.84 (A), 0.89 (B), 0.87 (C), and 0.90 (D), with the assistance of DL.
CONCLUSIONS: Use of DL algorithms on musculoskeletal dynamic contrast-enhanced MRI improved the benign-malignant differentiation accuracy of radiologists to a level comparable to that of pre-surgical biopsies. The developed DL algorithms have a potential to lower the risk of miss-diagnosing malignancy in radiological practice.