Imaging Features of Uncommon Entities That Manifest with Torsion.

Torsion is the twisting of an object along the axis, and various structures (organs and tumors) in the body can twist. Torsion causes initial lymphatic and venous outflow obstruction, leading to congestive edema, enlargement, venous hemorrhagic infarction, and surrounding edema. It can also cause subsequent arterial obstruction depending on the degree of torsion, leading to ischemia, infarction, necrosis, gangrene, and surrounding inflammation. Therefore, in several cases of torsion, immediate surgical intervention is required to improve blood flow and prevent serious complications. Clinical manifestations of torsion are often nonspecific and can affect individuals of varying ages and sex. Imaging plays an important role in the early diagnosis and management of torsion. Multiple imaging modalities, including US, radiography, CT, and MRI, are used to evaluate torsion, and each modality has its specific characteristics. The imaging findings reflect the pathophysiologic mechanism: a twisted pedicle (whirlpool sign), enlargement of the torsed structures, reduced blood flow, internal heterogeneity, and surrounding reactive changes. The whirlpool sign is a definitive characteristic of torsion. In some cases, despite poor internal enhancement, capsular enhancement is observed on contrast-enhanced CT and MR images and is considered to be associated with preserved capsular arterial flow or capsular neovascularization due to inflammation. Radiologists should be familiar with the pathophysiologic mechanisms, clinical characteristics, and imaging characteristics of torsion in various structures in the body. Since other articles about common organ torsions already exist, the authors of this article focus on the uncommon entities that manifest with torsion. ©RSNA, 2024.

Localization of the central sulcus using the distinctive high signal intensity of the paracentral lobule on T1-weighted images.

PURPOSE: The central sulcus is an important landmark in the brain. This study aimed to investigate the distinctive signal of the paracentral lobule (PL) on T1-weighted images (T1WIs; the white PL sign) and evaluate its usefulness as a new method of identifying the central sulcus. METHODS: T1WIs of the brain of 96 participants (age, 58.9 ± 17.9 years; range, 8-87 years) scanned at 3-T MR system were retrospectively reviewed. First, we qualitatively analyzed the signal of the cortex of the PL by comparing it with that of the ipsilateral superior frontal gyrus on a 4-point grading score. Second, we compared the cortical signal intensity and gray/white-matter contrast between the PL and superior frontal gyrus. Third, we evaluated the usefulness of the PL signal for identifying the central sulcus. RESULTS: The PL cortex was either mildly hyperintense (grade 2) or definitely hyperintense (grade 3) in comparison with that of superior frontal cortex in all participants. The signal intensity of the PL cortex was significantly higher than that of the superior frontal cortex (p < 0.001), whereas the gray/white-matter contrast of the PL was weaker than that of the superior frontal gyrus (p < 0.001). The central sulci were identified with 94.3% accuracy (181/192) using the new method. CONCLUSION: The white PL sign may be helpful in identifying the central sulcus, and this approach can be recognized as a new method for identification of the central sulcus.

Prediction of Abdominal Aortic Aneurysm Growth After Endovascular Aortic Repair by Measuring Brachial-Ankle Pulse Wave Velocity.

BACKGROUND: Although endovascular aortic repair (EVAR) has become the dominant therapeutic approach for abdominal aortic aneurysm (AAA), continued sac growth after EVAR remains a major concern and is still unpredictable. Since AAA formation is thought to arise from atherosclerotic vascular damage of the aortic wall, we hypothesize that the severity of atherosclerosis in the AAA wall may influence sac growth. Therefore, we investigated whether brachial-ankle pulse wave velocity (baPWV), a marker of atherosclerosis severity obtained by noninvasive automatic devices, can predict sac growth after EVAR. METHODS: The data from all patients who underwent elective EVAR for AAA at a single institution from January 2012 to March 2019 were reviewed. We extracted the baPWV before EVAR and divided patients into 2 groups according to the baPWV cut-off value identified by a classification and regression tree (CART). The primary outcome was significant sac growth, defined as an increment of 5 mm or more in aneurysm size after EVAR relative to the aneurysm size before EVAR. Cox regression analysis was performed to assess the potential predictors of sac growth. RESULTS: During the follow-up period, 222 consecutive patients underwent elective EVAR for AAA. Of these, 175 patients with a median follow-up period of 36 months were included. The baPWV values were classified as <1854 cm/s (Group 0) in 100 patients and ≥1854 cm/s (Group 1) in 75 patients according to the cut-off value identified by CART. During the follow-up period, 10 (10.0%) patients in Group 0 and 18 (24.0%) patients in Group 1 demonstrated significant sac growth (P = 0.021). Risk factors for significant sac growth included baPWV (hazard ratio [HR], 3.059; 95% confidence interval [CI], 1.41-6.64; P = 0.005), age (HR, 1.078; 95% CI, 1.01-1.16; P = 0.036), and persistent type II endoleak (HR, 3.552; 95% CI, 1.69-7.48; P < 0.001). Multivariate analysis revealed that baPWV remained a significant risk factor for sac growth after adjustment for age (HR, 2.602; 95% CI, 1.15-5.82; P = 0.02) and persistent type II endoleak (HR, 2.957; 95% CI, 1.36-6.43; P = 0.006). CONCLUSIONS: The baPWV before EVAR was associated with significant sac growth after EVAR; thus, measuring the baPWV may be useful for assessing the risk of future sac growth in patients after EVAR.

Recognizing Radiation-induced Changes in the Central Nervous System: Where to Look and What to Look For.

Radiation therapy (RT) continues to play a central role as an effective therapeutic modality for a variety of tumors and vascular malformations in the central nervous system. Although the planning and delivery techniques of RT have evolved substantially during the past few decades, the structures surrounding the target lesion are inevitably exposed to radiation. A wide variety of radiation-induced changes may be observed at posttreatment imaging, which may be confusing when interpreting images. Histopathologically, radiation can have deleterious effects on the vascular endothelial cells as well as on neuroglial cells and their precursors. In addition, radiation induces oxidative stress and inflammation, leading to a cycle of further cellular toxic effects and tissue damage. On the basis of the time of expression, radiation-induced injury can be divided into three phases: acute, early delayed, and late delayed. Acute and early delayed injuries are usually transient and reversible, whereas late delayed injuries are generally irreversible. The authors provide a comprehensive review of the timeline and expected imaging appearances after RT, including the characteristic imaging features after RT with concomitant chemotherapy. Specific topics discussed are imaging features that help distinguish expected posttreatment changes from recurrent disease, followed by a discussion on the role of advanced imaging techniques. Knowledge of the RT plan, the amount of normal structures included, the location of the target lesion, and the amount of time elapsed since RT is highly important at follow-up imaging, and the reporting radiologist should be able to recognize the characteristic imaging features after RT and differentiate these findings from tumor recurrence. ©RSNA, 2020.

Computed tomography findings of early-stage TAFRO syndrome and associated adrenal abnormalities.

OBJECTIVES: To compare CT findings of early (within 3 weeks post-onset)- and later (within 1 month before or after diagnostic criteria were satisfied, and later than 3 weeks post-onset) stage thrombocytopenia, anasarca, fever, reticulin fibrosis, renal dysfunction, and organomegaly (TAFRO) syndrome. METHODS: Between 2014 and 2019, 13 patients with TAFRO syndrome (8 men and 5 women; mean age, 54.9 years) from nine hospitals were enrolled. The number of the following CT findings (CT factors) was recorded: the presence of anasarca, organomegaly, adrenal ischaemia, anterior mediastinal lesion, bony lesion, and lymphadenopathy. Records of adrenal disorders (adrenomegaly, ischaemia, and haemorrhage) throughout the disease course were also collected. Differences in CT factors at each stage were statistically compared between remission and deceased groups. RESULTS: Para-aortic oedema and mild lymphadenopathy were observed in all patients, whereas pleural effusion, ascites, and subcutaneous oedema were found in 5/13, 7/13, and 7/13 cases, respectively, at the early stage. CT factors at the early stage were significantly higher in the deceased than in the remission group (mean, 11 vs 6.5; p = 0.04), while they were nonsignificant at the later stage. Adrenal disorders were present in 7/13 cases throughout the course including 6 of adrenomegaly and 4 of ischaemia at the early stage. CONCLUSIONS: Para-aortic oedema and mild lymphadenopathy are most common at the early stage. Anasarca, organomegaly, lymphadenopathy, and adrenal disorders on early-stage CT are useful for unfavourable prognosis prediction. Moreover, adrenal disorders are frequent even at the early stage and are useful for early diagnosis of TAFRO syndrome. KEY POINTS: • CT findings facilitate early diagnosis and prognosis prediction in TAFRO syndrome. • Adrenal disorders are frequently observed in TAFRO syndrome. • Adrenal disorders are useful for differential diagnosis of TAFRO syndrome.

Accelerated acquisition of carotid MR angiography using 3D gradient-echo imaging with two-point Dixon.

This pilot study tests the feasibility of rapid carotid MR angiography using the liver acquisition with volume acceleration-flex technique (LAVA MRA). Seven healthy volunteers and 21 consecutive patients suspected of carotid stenosis underwent LAVA and conventional time-of-flight (cTOF) MRAs. Artery-to-fat and artery-to-muscle signal intensity ratios were manually measured. LAVA MRA exhibited a significantly larger artery-to-fat signal intensity ratio compared with cTOF MRA in all slices (P < 0.001) and exhibited a larger (P < 0.001) or equivalent (P = 1.0) artery-to-muscle signal intensity ratio in the extracranial carotid arteries. The image quality of the cervical carotid bifurcation and the signal change on each MRA were visually assessed and compared among the MRAs. There was no significant difference between the two MRAs in visual assessment. LAVA MRA can provide visualization similar to cTOF MRA in the evaluation of the cervical carotid bifurcation while reducing scan time by one-fifth.

Biallelic COLGALT1 variants are associated with cerebral small vessel disease.

OBJECTIVE: Approximately 5% of cerebral small vessel diseases are hereditary, which include COL4A1/COL4A2-related disorders. COL4A1/COL4A2 encode type IV collagen α1/2 chains in the basement membranes of cerebral vessels. COL4A1/COL4A2 mutations impair the secretion of collagen to the extracellular matrix, thereby resulting in vessel fragility. The diagnostic yield for COL4A1/COL4A2 variants is around 20 to 30%, suggesting other mutated genes might be associated with this disease. This study aimed to identify novel genes that cause COL4A1/COL4A2-related disorders. METHODS: Whole exome sequencing was performed in 2 families with suspected COL4A1/COL4A2-related disorders. We validated the role of COLGALT1 variants by constructing a 3-dimensional structural model, evaluating collagen ß (1-O) galactosyltransferase 1 (ColGalT1) protein expression and ColGalT activity by Western blotting and collagen galactosyltransferase assays, and performing in vitro RNA interference and rescue experiments. RESULTS: Exome sequencing demonstrated biallelic variants in COLGALT1 encoding ColGalT1, which was involved in the post-translational modification of type IV collagen in 2 unrelated patients: c.452 T > G (p.Leu151Arg) and c.1096delG (p.Glu366Argfs*15) in Patient 1, and c.460G > C (p.Ala154Pro) and c.1129G > C (p.Gly377Arg) in Patient 2. Three-dimensional model analysis suggested that p.Leu151Arg and p.Ala154Pro destabilized protein folding, which impaired enzymatic activity. ColGalT1 protein expression and ColGalT activity in Patient 1 were undetectable. RNA interference studies demonstrated that reduced ColGalT1 altered COL4A1 secretion, and rescue experiments showed that mutant COLGALT1 insufficiently restored COL4A1 production in cells compared with wild type. INTERPRETATION: Biallelic COLGALT1 variants cause cerebral small vessel abnormalities through a common molecular pathogenesis with COL4A1/COL4A2-related disorders. Ann Neurol 2018;84:843-853.

Spinal cord swelling in patients with cervical compression myelopathy.

BACKGROUND: Intramedullary hyperintense lesions associated with spinal cord edema on T2-weighted MR images (T2WI) are rare findings in patients with cervical spondylosis and are poorly characterized. We investigated the clinical characteristics of spinal cord edema due to cervical spondylosis (SCECS). METHODS: In total, 214 patients with cervical spondylotic myelopathy who underwent surgery between April 2007 and March 2017 were divided into SCECS and non-SCECS groups with SCECS defined as follows: (1) intramedullary signal intensity (ISI) of the cervical spinal cord in sagittal T2WI extending to more than one vertebral body height; (2) "fuzzy" ISI, recognized as a faint intramedullary change with a largely indistinct and hazy border; and (3) a larger sagittal diameter of the spinal cord segment with ISI just above or below the cord compression area compared with areas of the cervical spine without ISI. Radiographic parameters, demographic characteristics, and the Japanese Orthopedic Association (JOA) surgical outcomes score were compared between the groups. RESULTS: Seventeen patients (7.9%) were diagnosed with SCECS. These patients were younger than those in the non-SCECS group [median (interquartile range), 64 (20) vs. 69 (15) years, respectively, p = 0.016], and the disease duration from onset to surgery was significantly shorter in the SCECS group than in the non-SCECS group [6 (7) vs. 20 (48) months, respectively]. No significant difference was observed between groups with respect to sex, radiologic findings, or surgical outcomes. CONCLUSION: The disease showed an earlier onset and more rapid progression in the patients with SCECS than in those without SCECS.

Clinical Features of Acute Flaccid Myelitis Temporally Associated With an Enterovirus D68 Outbreak: Results of a Nationwide Survey of Acute Flaccid Paralysis in Japan, August-December 2015.

Background: Acute flaccid myelitis (AFM) is an acute flaccid paralysis syndrome with spinal motor neuron involvement of unknown etiology. We investigated the characteristics and prognostic factors of AFM clusters coincident with an enterovirus D68 (EV-D68) outbreak in Japan during autumn 2015. Methods: An AFM case series study was conducted following a nationwide survey from August to December 2015. Radiographic and neurophysiologic data were subjected to centralized review, and virology studies were conducted for available specimens. Results: Fifty-nine AFM cases (58 definite, 1 probable) were identified, including 55 children and 4 adults (median age, 4.4 years). The AFM epidemic curve showed strong temporal correlation with EV-D68 detection from pathogen surveillance, but not with other pathogens. EV-D68 was detected in 9 patients: 5 in nasopharyngeal, 2 in stool, 1 in cerebrospinal fluid (adult case), and 1 in tracheal aspiration, nasopharyngeal, and serum samples (a pediatric case with preceding steroid usage). Cases exhibited heterogeneous paralysis patterns from 1- to 4-limb involvement, but all definite cases had longitudinal spinal gray matter lesions on magnetic resonance imaging (median, 20 spinal segments). Cerebrospinal fluid pleocytosis was observed in 50 of 59 cases (85%), and 8 of 29 (28%) were positive for antiganglioside antibodies, as frequently observed in Guillain-Barré syndrome. Fifty-two patients showed variable residual weakness at follow-up. Good prognostic factors included a pretreatment manual muscle strength test unit score >3, normal F-wave persistence, and EV-D68-negative status. Conclusions: EV-D68 may be one of the causative agents for AFM, while host susceptibility factors such as immune response could contribute to AFM development.

Diffusional kurtosis imaging and white matter microstructure modeling in a clinical study of major depressive disorder.

Major depressive disorder (MDD) is a globally prevalent psychiatric disorder that results from disruption of multiple neural circuits involved in emotional regulation. Although previous studies using diffusion tensor imaging (DTI) found smaller values of fractional anisotropy (FA) in the white matter, predominantly in the frontal lobe, of patients with MDD, studies using diffusion kurtosis imaging (DKI) are scarce. Here, we used DKI whole-brain analysis with tract-based spatial statistics (TBSS) to investigate the brain microstructural abnormalities in MDD. Twenty-six patients with MDD and 42 age- and sex-matched control subjects were enrolled. To investigate the microstructural pathology underlying the observations in DKI, a compartment model analysis was conducted focusing on the corpus callosum. In TBSS, the patients with MDD showed significantly smaller values of FA in the genu and frontal portion of the body of the corpus callosum. The patients also had smaller values of mean kurtosis (MK) and radial kurtosis (RK), but MK and RK abnormalities were distributed more widely compared with FA, predominantly in the frontal lobe but also in the parietal, occipital, and temporal lobes. Within the callosum, the regions with smaller MK and RK were located more posteriorly than the region with smaller FA. Model analysis suggested significantly smaller values of intra-neurite signal fraction in the body of the callosum and greater fiber dispersion in the genu, which were compatible with the existing literature of white matter pathology in MDD. Our results show that DKI is capable of demonstrating microstructural alterations in the brains of patients with MDD that cannot be fully depicted by conventional DTI. Though the issues of model validation and parameter estimation still remain, it is suggested that diffusion MRI combined with a biophysical model is a promising approach for investigation of the pathophysiology of MDD.

Single-energy metal artifact reduction technique for reducing metallic coil artifacts on post-interventional cerebral CT and CT angiography.

PURPOSE: To evaluate the effects of the single-energy metal artifact reduction (SEMAR) algorithm on image quality of cerebral CT and CT angiography (CTA) for patients who underwent intracranial aneurysm coiling. METHODS: Twenty patients underwent cerebral CT and CTA using a 320-detector row CT after intracranial aneurysm coiling. Images with and without application of the SEMAR algorithm (SEMAR CT and standard CT images, respectively) were reconstructed for each patient. The images were qualitatively assessed by two independent radiologists in a blinded manner for the depiction of anatomical structures around the coil, delineation of the arteries around the coil, and the depiction of the status of coiled aneurysms. Artifact strength was quantitatively assessed by measuring the standard deviation of attenuation values around the coil. RESULTS: The strength of artifacts measured in SEMAR CT images was significantly lower than that in standard CT images (25.7 ± 10.2 H.U. vs. 80.4 ± 67.2 H.U., p < 0.01, Student's paired t test). SEMAR CT images were significantly improved compared with standard CT images in the depiction of anatomical structures around the coil (p < 0.01, the sign test), delineation of the arteries around the coil (p < 0.01), and the depiction of the status of coiled aneurysms (p < 0.01). CONCLUSION: The SEMAR algorithm significantly reduces metal artifacts from intracranial aneurysm coiling and improves visualization of anatomical structures and arteries around the coil, and depiction of the status of coiled aneurysms on post-interventional cerebral CT.

Low CT Attenuation Values of Sinonasal Benign Tumours Relative to the Brainstem Identify Schwannomas.

OBJECTIVES: On computed tomography (CT), sinonasal schwannoma displays as a soft-tissue mass without any distinctive features. Our aim was to define the radiological criteria for distinguishing schwannoma from other sinonasal benign tumours. METHODS: We retrospectively identified consecutive patients who were pathologically diagnosed with benign sinonasal tumours between 2007 and 2016. CT attenuation values were compared between benign tumours and the brainstem. The utilities of demographic factors, clinical factors, and CT parameters for predicting the CT attenuation values of the brainstem were analysed by univariate and multivariate regression. RESULTS: Of the 111 identified cases of benign tumours, the CT attenuation values of tumours and the brainstem were analysed in 36 cases (schwannoma, 4 cases; inverted papilloma, 26; juvenile nasopharyngeal angiofibroma, 3; cavernous haemangioma, 3). The CT attenuation values of the schwannomas were significantly lower than in the brainstem, while those of the other tumours were significantly higher than in the brainstem. No factors affected the CT attenuation values of the brainstem. CONCLUSION: Low CT attenuation values of sinonasal benign tumours relative to the brainstem could distinguish schwannomas from other benign tumours.

Feasibility of diffusion tensor tractography for preoperative prediction of the location of the facial and vestibulocochlear nerves in relation to vestibular schwannoma.

BACKGROUND: According to recent findings, diffusion tensor tractography (DTT) only allows prediction of facial nerve location in relation to vestibular schwannoma (VS) with high probability. However, previous studies have not mentioned why only the facial nerve was selectively visualized. Our previous report investigated the optimal conditions of DTT for normal facial and vestibulocochlear nerves. In the present study, we applied the optimal conditions of DTT to VS patients to assess the feasibility of DTT for the facial and vestibulocochlear nerves. METHODS: We investigated 11 patients with VS who underwent tumor resection. Visualized tracts were compared with locations of the facial and cochlear nerves as identified by intraoperative electrophysiological monitoring. RESULTS: With the proposed method, visualized tracts corresponded to pathway area of the facial or cochlear nerves in nine of 11 patients (81.8%); specifically, to the pathway area of the facial nerve in three of 11 patients (27.3%), and to the pathway area of the cochlear nerve in six of 11 patients (54.5%). CONCLUSIONS: We visualized facial or vestibulocochlear nerves in nine of 11 patients (81.8%). For the first time, DTT proved able to visualize not only the facial nerve but also the vestibulocochlear nerve in VS patients. Despite our findings, good methods for distinguishing whether a visualized nerve tract represents facial nerve, vestibulocochlear nerve, or only noise remain unavailable. Close attention should therefore be paid to the interpretation of visualized fibers.

Non-Gaussian diffusion-weighted imaging for assessing diurnal changes in intervertebral disc microstructure.

PURPOSE: To investigate the use of non-Gaussian diffusion-weighted imaging (q-space imaging [QSI]) to estimate diurnal changes in intervertebral disc (IVD) microstructure. MATERIALS AND METHODS: IVDs of 15 male subjects (mean age, 27.3 years; mean body mass index, 22.50 kg/m(2) ) were investigated once in the morning, less than 30 min after rising, and a second time in the evening after at least 10 h of normal physical activity, using 3 Tesla (T) MR imaging. T2 mapping and QSI data values (apparent diffusion coefficient [ADC], root mean square displacement [RMSD], and apparent kurtosis coefficient [AKC]) were calculated and compared between the morning and evening imaging sessions. RESULTS: The T2, ADC, and RMSD values showed a significant decrease in the evening (175.8 ± 49.5 ms, 1.56 ± 0.32 10(-3) mm(2) /s and 40.0 ± 3.0 µm, respectively; P < 0.05 for all values; paired t-test), when compared with the morning values (226.5 ± 83.8 ms, 1.69 ± 0.29 10(-3) mm(2) /s and 45.2 ± 2.9 µm, respectively). The AKC value showed a significant increase in the evening (0.67 ± 0.08), when compared with the morning value (0.58 ± 0.04; P < 0.05). CONCLUSION: The RMSD and AKC values obtained from QSI analysis may be biomarkers for IVD diurnal microstructural changes.

Database of normal Japanese gray matter volumes in the default mode network.

PURPOSE: To show the gray matter volumes in the default mode network (DMN) using the atlas-based method and to evaluate age-related volume change in the DMN region. Estimation of gray matter volumes is interesting research because previous reports showed an association with gray matter volume (GMV) and diseases. MATERIALS AND METHODS: We focused on five nodes of the DMN (posterior cingulate, precuneus, lateral temporal cortex [LTC], medial prefrontal cortex, and inferior parietal lobule). In all, 1122 healthy adults were included in the present study. T1-weighted magnetic resonance (MR) images were obtained using a 3T-MR scanner. To investigate GMV in the DMN, segmented gray matter images were measured by the atlas-based method, using Statistical Parametric Mapping 5. Volumes were expressed using three different methods: region of interest (ROI)-volume (mL), the volume itself; ROI-TIV (%), as a percentage of total intracranial volume (individual difference of head size is corrected); and ROI-GMV (%), as a percentage of gray matter volume (individual difference of atrophy speed for aging is corrected). RESULTS: Negative correlations between measurement values on ROI and age were observed in all five ROIs of the DMN region by two measures of volume (ROI-volume (mL) and ROI-TIV (%)), in both genders. In contrast, positive correlations between measurement values on ROI and age were observed in the posterior cingulate and LTC with ROI-GMV (%), in both genders. CONCLUSION: The present study is the first report about volume change in the DMN that includes age-related effects.

Computed tomography findings of ongoing subgaleal hemorrhage.

Neonatal subgaleal hemorrhage (SGH) is a serious adverse event that is often underestimated and sometimes goes unrecognized. It can cause bleeding complications and jeopardize the patient's life. Early diagnosis and prompt treatment are important in optimizing the outcome in neonates with SGH. Herein we describe the case of a newborn who developed severe SGH and died. We report unenhanced computed tomography (CT) of ongoing SGH, which showed a low-density region in the surrounding area of the head. The density could be explained by unclotted active bleeding and low hematocrit. Even if a patient with clinically suspected SGH has a low-density region on CT, the presence of SGH should not be excluded.

Impact of CT-determined low kidney volume on renal function decline: a propensity score-matched analysis.

OBJECTIVES: To investigate the relationship between low kidney volume and subsequent estimated glomerular filtration rate (eGFR) decline in eGFR category G2 (60-89 mL/min/1.73 m2) population. METHODS: In this retrospective study, we evaluated 5531 individuals with eGFR category G2 who underwent medical checkups at our institution between November 2006 and October 2017. Exclusion criteria were absent for follow-up visit, missing data, prior renal surgery, current renal disease under treatment, large renal masses, and horseshoe kidney. We developed a 3D U-net-based automated system for renal volumetry on CT images. Participants were grouped by sex-specific kidney volume deviations set at mean minus one standard deviation. After 1:1 propensity score matching, we obtained 397 pairs of individuals in the low kidney volume (LKV) and control groups. The primary endpoint was progression of eGFR categories within 5 years, assessed using Cox regression analysis. RESULTS: This study included 3220 individuals (mean age, 60.0 ± 9.7 years; men, n = 2209). The kidney volume was 404.6 ± 67.1 and 376.8 ± 68.0 cm3 in men and women, respectively. The low kidney volume (LKV) cutoff was 337.5 and 308.8 cm3 for men and women, respectively. LKV was a significant risk factor for the endpoint with an adjusted hazard ratio of 1.64 (95% confidence interval: 1.09-2.45; p = 0.02). CONCLUSION: Low kidney volume may adversely affect subsequent eGFR maintenance; hence, the use of imaging metrics may help predict eGFR decline. CRITICAL RELEVANCE STATEMENT: Low kidney volume is a significant predictor of reduced kidney function over time; thus, kidney volume measurements could aid in early identification of individuals at risk for declining kidney health. KEY POINTS: • This study explores how kidney volume affects subsequent kidney function maintenance. • Low kidney volume was associated with estimated glomerular filtration rate decreases. • Low kidney volume is a prognostic indicator of estimated glomerular filtration rate decline.

A Case of Solid-Appearing Struma Ovarii: Pitfall in the Assessment Using Ovarian-Adnexal Reporting and Data System Magnetic Resonance Imaging Score.

Struma ovarii is a monodermal teratoma characterized by the presence of >50% thyroid tissue. It is mostly benign; therefore, preoperative diagnosis is important. It usually manifests as a multilocular cystic mass but rarely as a predominantly solid mass. On magnetic resonance imaging (MRI), solid-appearing struma ovarii showed early signal intensity enhancement on dynamic gadolinium-enhanced T1-weighted images, which histopathologically indicates the presence of thyroid tissue with abundant blood vessels. The Ovarian-Adnexal Reporting and Data System (O-RADS) MRI score is a validated classification worldwide for characterizing adnexal lesions. Based on the morphology, signal intensity, and enhancement of any solid tissue on the MRI, the scoring system can be used to classify adnexal lesions into five categories from score one (no adnexal mass) to score five (high risk of malignancy). An adnexal solid mass with a higher signal intensity than that of the myometrium 30-40 seconds after gadolinium (Gd) injection on non-dynamic contrast-enhanced (non-DCE) MRI was assigned a score of 5 (high risk of malignancy).  We present a case of solid-appearing struma ovarii with a higher signal intensity than that of the myometrium 30 seconds after Gd injection on non-DCE MRI, and it was classified as score five preoperatively. Therefore, a total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed despite the presence of a benign ovarian mass. When an adnexal mass with a higher signal intensity than that of the myometrium 30-40 seconds after Gd injection on non-DCE MRI is encountered, struma ovarii should be included in the differential diagnosis, despite the O-RADS MRI score of five and management of the situation should be discussed.

Towards Improved Radiological Diagnostics: Investigating the Utility and Limitations of GPT-3.5 Turbo and GPT-4 with Quiz Cases.

BACKGROUND AND PURPOSE: The rise of large language models such as generative pre-trained transformers (GPTs) has sparked significant interest in radiology, especially in interpreting radiological reports and image findings. While existing research has focused on GPTs estimating diagnoses from radiological descriptions, exploring alternative diagnostic information sources is also crucial. This study introduces the use of GPTs (GPT-3.5 Turbo and GPT-4) for information retrieval and summarization, searching relevant case reports via PubMed, and investigates their potential to aid diagnosis. MATERIALS AND METHODS: From October 2021 to December 2023, we selected 115 cases from the "Case of the Week" series on the American Journal of Neuroradiology website. Their Description and Legend sections were presented to the GPTs for the two tasks. For the Direct Diagnosis task, the models provided three differential diagnoses that were considered correct if they matched the diagnosis in the diagnosis section. For the Case Report Search task, the models generated two keywords per case, creating PubMed search queries to extract up to three relevant reports. A response was considered correct if reports containing the disease name stated in the diagnosis section were extracted. McNemar's test was employed to evaluate whether adding a Case Report Search to Direct Diagnosis improved overall accuracy. RESULTS: In the Direct Diagnosis task, GPT-3.5 Turbo achieved a correct response rate of 26% (30/115 cases), whereas GPT-4 achieved 41% (47/115). For the Case Report Search task, GPT-3.5 Turbo scored 10% (11/115), and GPT-4 scored 7% (8/115). Correct responses totaled 32% (37/115) with three overlapping cases for GPT-3.5 Turbo, whereas GPT-4 had 43% (50/115) of correct responses with five overlapping cases. Adding Case Report Search improved GPT-3.5 Turbo's performance (p = 0.023) but not that of GPT-4 (p = 0.248). CONCLUSIONS: The effectiveness of adding Case Report Search to GPT-3.5 Turbo was particularly pronounced, suggesting its potential as an alternative diagnostic approach to GPTs, particularly in scenarios where direct diagnoses from GPTs are not obtainable. Nevertheless, the overall performance of GPT models in both direct diagnosis and case report retrieval tasks remains not optimal, and users should be aware of their limitations.ABBREVIATIONS: AI = Artificial Intelligence, GPT = generative pretrained transformer, LLM = large language model.