The retrocaval ureter - A rare developmental cause for urinary tract obstruction.

Retrocaval ureter is a rare congenital anomaly with few reported cases worldwide. In this case report, we describe a clinical presentation that demonstrates the stereotypical imaging features of a retrocaval ureter on ultrasound, computed tomography and nuclear imaging studies in a 38-year-old male patient who fits the classic reported patient demographics.

Diagnostic accuracy of contrast-enhanced CT versus PET/CT for advanced ovarian cancer staging: a comparative systematic review and meta-analysis.

PURPOSE: Accurate staging of ovarian cancer is critical to guide optimal management pathways. North American guidelines recommend contrast-enhanced CT as the primary work-up for staging ovarian cancer. This meta-analysis aims to compare the diagnostic accuracy of contrast-enhanced CT alone to PET/CT for detecting abdominal metastases in patients with a new or suspected diagnosis of ovarian cancer. MATERIALS AND METHODS: A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and the gray literature from inception to October 2022 was performed. Studies with a minimum of 5 patients evaluating the diagnostic accuracy of contrast-enhanced CT and/or PET/CT for detecting stage 3 ovarian cancer as defined by a surgical/histopathological reference standard ± clinical follow-up were included. Study, clinical, imaging, and accuracy data for eligible studies were independently acquired by two reviewers. Primary meta-analysis was performed in studies reporting accuracy on a per-patient basis using a bivariate mixed-effects regression model. Risk of bias was evaluated using QUADAS-2. RESULTS: From 3701 citations, 15 studies (918 patients with mean age ranging from 51 to 65 years) were included in the systematic review. Twelve studies evaluated contrast-enhanced CT (6 using a per-patient assessment and 6 using a per-region assessment) and 11 studies evaluated PET/CT (7 using a per-patient assessment and 4 using a per-region assessment). All but one reporting study used consensus reading. Respective sensitivity and specificity values on a per-patient basis were 82% (67-91%, 95% CI) and 72% (59-82%) for contrast-enhanced CT and 87% (75-94%) and 90% (82-95%) for PET/CT. There was no significant difference in sensitivities between modalities (p = 0.29), but PET/CT was significantly more specific than CT (p < 0.01). Presumed variability could not be assessed in any single category due to limited studies using per-patient assessment. Studies were almost entirely low risk for bias and applicability concerns using QUADAS-2. CONCLUSION: Contrast-enhanced CT demonstrates non-inferior sensitivity compared to PET/CT, although PET/CT may still serve as an alternative and/or supplement to CT alone prior to and/or in lieu of diagnostic laparoscopy in patients with ovarian cancer. Future revisions to existing guidelines should consider these results to further refine the individualized pretherapeutic diagnostic pathway.

Cushing's syndrome diagnosed incidentally on CT imaging.

In this case report, we describe an uncommon presentation of Cushing's syndrome in a patient in their 60s who presented to the emergency department with left-sided chest pain. The initial workup for the patient was unremarkable except for an elevated blood pressure and elevated fasting plasma glucose. A CT scan of the chest, abdomen and pelvis was performed, demonstrating a splenic artery thrombus with multiple splenic infarcts, in addition to a combination of macronodular adrenal hyperplasia, bilateral gynecomastia, centripetal fat distribution and suspected mild bone demineralisation. Adrenocorticotropic hormone-independent macronodular adrenal hyperplasia, a rare aetiology responsible for Cushing's syndrome, was raised as a potential unifying diagnosis for the patient's hypercoagulable status, which was subsequently confirmed on an endocrinological investigation. The case report underscores the importance of communicating clinically relevant details to the imaging specialist in combination with considering a broad differential, including endocrine disorders, when evaluating an undifferentiated patient with atypical imaging findings.

An open label feasibility study of a nutrition and exercise app-based solution in cirrhosis.

Background: Nutrition and exercise are the mainstay of therapy for the prevention and treatment of frailty in cirrhosis. This pilot study assessed feasibility of the online delivery of an app-based semi-supervised nutrition and exercise intervention in this population. Methods: The 11-week pilot recruited adults with cirrhosis who owned internet-connected devices. Patients were encouraged to participate in exercise sessions 3× per week including a combination of online group exercise (weekly) and home-based follow-along exercise (biweekly). They also participated in group nutrition classes (five sessions) and one-to-one exercise and nutrition check-ins delivered through the app. Primary outcome measures pertained to program feasibility: recruitment, retention, adherence, and satisfaction. Exploratory measures included physical performance (liver frailty index [LFI], 6-minute walk test [6MWT]), health behaviour domains, and quality of life. Results: Twenty three patients completed baseline measures. Of these, 18 (72%) completed end of study measures (mean MELD-Na, 9.2; female, 44.4%). Over 70% of participants fulfilled 75% or more of the feasibility criteria. Satisfaction with the program was high (mean, 89%). Exercise program modifications were required for 17 patients to accommodate health events or abilities. Exploratory evaluation showed improvement in the LFI and the 6MWT by -0.58-units (95% CI: -0.91 to -0.25) and 46.0 m (95% CI: 22.7-69.3) respectively without changes in quality of life or health behaviour domains. Conclusions: Outcomes demonstrate feasibility of the app-based delivery of programming with promising exploratory impact on efficacy for physical performance. Findings can guide the design of a large-scale app-based randomized controlled trials in cirrhosis.

Evolution of spontaneous portosystemic shunts over time and following aetiological intervention in patients with cirrhosis.

Background & Aims: Spontaneous portosystemic shunts (SPSS) develop frequently in cirrhosis. Changes over time and the effect of aetiological interventions on SPSS are unknown, so we aimed to explore the effect of these variables on SPSS evolution. Methods: Patients with cirrhosis from the Baveno VI-SPSS cohort were selected provided a follow-up abdominal CT or MRI scan was available. Clinical and laboratory data were collected at baseline and follow-up. Imaging tests were reviewed to evaluate changes in the presence and size of SPSS (large (L)-SPSS was ≥8 mm) over time. Regarding alcohol- or HCV-related cirrhosis, two populations were defined: cured patients (abstinent from alcohol or successful HCV therapy), and non-cured patients. Results: A total of 617 patients were included. At baseline SPSS distribution was 22% L-SPSS, 30% small (S)-SPSS, and 48% without (W)-SPSS. During follow-up (median follow-up of 63 months), SPSS distribution worsened: L-SPSS 26%, S-SPSS 32%, and W-SPSS 42% (p <0.001). Patients with worse liver function during follow-up showed a simultaneous aggravation in SPSS distribution. Non-cured patients (n = 191) experienced a significant worsening in liver function, more episodes of liver decompensation and lower transplant-free survival compared to cured patients (n = 191). However, no differences were observed regarding SPSS distribution at inclusion and at follow-up, with both groups showing a trend to worsening. Total shunt diameter increased more in non-cured (52%) than in cured patients (28%). However, total shunt area (TSA) significantly increased only in non-cured patients (74 to 122 mm2, p <0.001). Conclusions: The presence of SPSS in cirrhosis increases over time and parallels liver function deterioration. Aetiological intervention in these patients reduces liver-related complications, but SPSS persist although progression is decreased. Impact and implications: There is no information regarding the evolution of spontaneous portosystemic shunts (SPSS) during the course of cirrhosis, and especially after disease regression with aetiological interventions, such as HCV treatment with direct-acting antivirals or alcohol abstinence. These results are relevant for clinicians dealing with patients with cirrhosis and portal hypertension because they have important implications for the management of cirrhosis with SPSS after disease regression. From a practical point of view, physicians should be aware that in advanced cirrhosis with portal hypertension, after aetiological intervention, SPSS mostly persist despite liver function improvement, and complications related to SPSS may still develop.

Impact of Size Thresholds on the Diagnosis of Incidental Adrenal Lesions: A Systematic Review and Meta-Analysis.

BACKGROUND: Preferred size-threshold recommendations for management of incidental adrenal lesions remain controversial. PURPOSE: This meta-analysis aimed to compare the diagnostic accuracy of different size thresholds for detecting malignancy in patients with incidental adrenal lesions on imaging. MATERIALS AND METHODS: A systematic review of MEDLINE, Embase, Scopus, the Cochrane Library, and the gray literature, covering the period from inception to September 2021, was performed. Studies with >10 patients evaluating the diagnostic accuracy of imaging size thresholds for detecting malignancy in patients with incidental adrenal lesions and no prior history of cancer were included. Study, clinical, imaging, and accuracy data for eligible studies were independently acquired by two reviewers. Primary meta-analysis was performed using a bivariate mixed-effects regression model. Risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. RESULTS: From 2,690 citations, 40 studies (9,794 patients with mean age ranging from 41 to 66 years) were included. Most (36 of 40) were retrospective single-center studies. CT with or without MRI served as the index test(s). Sensitivity and specificity values, respectively, by size threshold used in the included studies were as follows: 85% (95% confidence interval [CI] 74%-91%) and 39% (95% CI 23%-57%) for 3-cm thresholds; 85% (95% CI 78%-90%) and 75% (95% CI 62%-85%) for 4-cm thresholds; 70% (95% CI 56%-81%) and 74% (95% CI 59%-85%) for 5-cm thresholds; and 75% (95% CI 67%-82%) and 77% (95% CI 62%-87%) for 6-cm thresholds. No cause for variability in sensitivity or specificity was identified on subgroup analysis of the 4-cm threshold. Nearly half of the studies (19 of 40) had at least one QUADAS-2 domain with a high risk of bias. CONCLUSIONS: A 4-cm size threshold demonstrates the highest combined sensitivity and specificity, with a preserved specificity compared with higher size thresholds, but with a trend toward improved sensitivity. Future research reevaluating 4-5 cm size thresholds while excluding characteristically benign lesions by imaging may help redefine a size threshold that has improved specificity but preserved sensitivity, compared with the existing 4-cm threshold.

Two-point Dixon and six-point Dixon magnetic resonance techniques in the detection, quantification and grading of hepatic steatosis.

BACKGROUND: Hepatic steatosis is a very common problem worldwide. AIM: To assess the performance of two- and six-point Dixon magnetic resonance (MR) techniques in the detection, quantification and grading of hepatic steatosis. METHODS: A single-center retrospective study was performed in 62 patients with suspected parenchymal liver disease. MR sequences included two-point Dixon, six-point Dixon, MR spectroscopy (MRS) and MR elastography. Fat fraction (FF) estimates on the Dixon techniques were compared to the MRS-proton density FF (PDFF). Statistical tests used included Pearson's correlation and receiver operating characteristic. RESULTS: FF estimates on the Dixon techniques showed excellent correlation (≥ 0.95) with MRS-PDFF, and excellent accuracy [area under the receiver operating characteristic (AUROC) ≥ 0.95] in: (1) Detecting steatosis; and (2) Grading severe steatosis, (P < 0.001). In iron overload, two-point Dixon was not evaluable due to confounding T2* effects. FF estimates on six-point Dixon vs MRS-PDFF showed a moderate correlation (0.82) in iron overload vs an excellent correlation (0.97) without iron overload, (P < 0.03). The accuracy of six-point Dixon in grading mild steatosis improved (AUROC: 0.59 to 0.99) when iron overload cases were excluded. The excellent correlation (> 0.9) between the Dixon techniques vs MRS-PDFF did not change in the presence of liver fibrosis (P < 0.01). CONCLUSION: Dixon techniques performed satisfactorily for the evaluation of hepatic steatosis but with exceptions.

Cystic retroperitoneal dedifferentiated liposarcoma: A case report.

Liposarcoma is the most common primary retroperitoneal sarcoma in adults. We report the case of an 86-year-old male who presented to the emergency department with frequent falls and unexplained weight loss that was found to have a cystic retroperitoneal dedifferentiated liposarcoma. Initial computed tomography revealed a large heterogeneous complex cystic hypoenhancing lesion in the left retroperitoneum. Subsequent magnetic resonance imaging demonstrates a multilocular cystic mass with microscopic lipid content, diffusion restriction, and enhancing nodular soft-tissue components. Histologic examination of the tissue sample following biopsy is consistent with cystic retroperitoneal dedifferentiated liposarcoma. Further management was not pursued due to the patient's advanced age and frailty.

Unilateral renal agenesis, blind-ended ureter, and ectopic ureterocele inserting into the seminal vesicle: A very rare developmental association.

Congenital renal anomalies are common imaging findings and can often be detected antenatally. In some cases, these anomalies may go undetected and present in adulthood. We report a very rare case of unilateral renal agenesis in a 22-year-old male associated with an ipsilateral dilated blind-ended ureter that ectopically inserted into the seminal vesicle. This unique combination of developmental anomalies can lead to a variety of clinical presentations and requires careful monitoring and management.

Diagnostic accuracy of CT and MR features for detecting atypical lipomatous tumors and malignant liposarcomas: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis evaluated the diagnostic accuracy of CT and MRI for differentiating atypical lipomatous tumors and malignant liposarcomas from benign lipomatous lesions. METHODS: MEDLINE, EMBASE, Scopus, the Cochrane Library, and the gray literature from inception to January 2022 were systematically evaluated. Original studies with > 5 patients evaluating the accuracy of CT and/or MRI for detecting liposarcomas with a histopathological reference standard were included. Meta-analysis was performed using a bivariate mixed-effects regression model. Risk of bias was evaluated using Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). This study is registered on PROSPERO, number CRD42022306479. RESULTS: Twenty-six studies with a total of 2613 patients were included. Mean/median reported patient ages ranged between 50 and 63 years. The summary sensitivity and specificity of radiologist gestalt for detecting liposarcomas was 85% (79-90% 95% CI) and 63% (52-72%), respectively. Deep depth to fascia, thickened septations, enhancing components, and lesion size (≥ 10 cm) all demonstrated sensitivities ≥ 85%. Other imaging characteristics including heterogenous/amorphous signal intensity, irregular tumor margin, and nodules present demonstrated lower sensitivities ranging from 43 to 65%. Inter-reader reliability for radiologist gestalt within studies ranged from fair to substantial (k = 0.23-0.7). Risk of bias was predominantly mixed for patient selection, low for index test and reference standard, and unclear for flow and timing. CONCLUSION: Higher sensitivities for detecting liposarcomas were achieved with radiologist gestalt, deep depth to fascia, thickened septations, enhancing components, and large size. Combined clinical and imaging scoring and/or radiomics both show promise for optimal performance, though require further analysis with prospective study designs. CLINICAL RELEVANCE: This pooled analysis evaluates the accuracy of CT and MRI for detecting atypical lipomatous tumors and malignant liposarcomas. Radiologist gestalt, deep depth to fascia, thickened septations, enhancing components, and large size demonstrate the highest overall sensitivities. KEY POINTS: • The summary sensitivity and specificity of radiologist gestalt for detecting liposarcomas was 85% (79-90% 95% CI) and 63% (52-72%), respectively. • Radiologist gestalt, deep depth to fascia, thickened septations, enhancing components, and large tumor size (≥ 10 cm) showed the highest sensitivities for detecting atypical lipomatous tumors/well-differentiated liposarcomas and malignant liposarcomas. • A combined clinical and imaging scoring system and/or radiomics is likely to provide the best overall diagnostic accuracy, although currently proposed scoring systems and radiomic feature analysis require further study with prospective study designs.

Adrenal Neoplasms: Lessons from Adrenal Multidisciplinary Tumor Boards.

The radiologic diagnosis of adrenal disease can be challenging in settings of atypical presentations, mimics of benign and malignant adrenal masses, and rare adrenal anomalies. Misdiagnosis may lead to suboptimal management and adverse outcomes. Adrenal adenoma is the most common benign adrenal tumor that arises from the cortex, whereas adrenocortical carcinoma (ACC) is a rare malignant tumor of the cortex. Adrenal cyst and myelolipoma are other benign adrenal lesions and are characterized by their fluid and fat content, respectively. Pheochromocytoma is a rare neuroendocrine tumor of the adrenal medulla. Metastases to the adrenal glands are the most common malignant adrenal tumors. While many of these masses have classic imaging appearances, considerable overlap exists between benign and malignant lesions and can pose a diagnostic challenge. Atypical adrenal adenomas include those that are lipid poor; contain macroscopic fat, hemorrhage, and/or iron; are heterogeneous and/or large; and demonstrate growth. Heterogeneous adrenal adenomas may mimic ACC, metastasis, or pheochromocytoma, particularly when they are 4 cm or larger, whereas smaller versions of ACC, metastasis, and pheochromocytoma and those with washout greater than 60% may mimic adenoma. Because of its nonenhanced CT attenuation of less than or equal to 10 HU, a lipid-rich adrenal adenoma may be mimicked by a benign adrenal cyst, or it may be mimicked by a tumor with central cystic and/or necrotic change such as ACC, pheochromocytoma, or metastasis. Rare adrenal tumors such as hemangioma, ganglioneuroma, and oncocytoma also may mimic adrenal adenoma, ACC, metastasis, and pheochromocytoma. The authors describe cases of adrenal neoplasms that they have encountered in clinical practice and presented to adrenal multidisciplinary tumor boards. Key lessons to aid in diagnosis and further guide appropriate management are provided. © RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Comparing the Denver criteria sets for blunt trauma: a retrospective study of cases in Edmonton, Alberta.

OBJECTIVE: To determine whether a more conservative Denver criterion set could reduce unnecessary CT angiography (CTA) studies when screening for blunt cerebrovascular injury (BCVI) following blunt trauma. METHODS: Following ethics approval, a retrospective chart review of 447 consecutive patients undergoing emergency CTA at two large teaching hospitals was conducted to determine the presence of risk factors for each Denver criterion set. Imaging studies of adults conducted between January 2016 and June 2020 containing sufficient clinical information for accurate classification were included in the study. Specificity, sensitivity, and predictive values were calculated. A two-sided Fisher exact test was used to evaluate the association between each iteration of the Denver criteria and the presence of BCVI. RESULTS: The specificities of the Original, Modified, and Expanded Denver criteria were 43.58%, 34.32%, and 24.85%, respectively. Positive-predictive values (PPV) followed a different trend, with respective values of 2.77%, 3.06%, and 2.78%. Sensitivity and negative-predictive values (NPV) were found to be 100% for each criterion set. Being positive for a criterion set, and the presence of BCVI, was statistically significant for the original Denver criteria (p = 0.021, n = 443), but not the modified (p = 0.100, n = 345) or expanded Denver criteria (p = 0.202, n = 333). CONCLUSION: Use of the modified and expanded Denver criteria leads to the overuse of cerebrovascular imaging on patients suffering blunt force trauma. ADVANCES IN KNOWLEDGE: The original Denver criteria may more appropriately identify subjects for further evaluation with CTA than the current standard, while retaining diagnostic efficacy for BCVI.

Multiparametric MR assessment of liver fat, iron, and fibrosis: a concise overview of the liver "Triple Screen".

Chronic liver disease (CLD) is a common source of morbidity and mortality worldwide. Non-alcoholic fatty liver disease (NAFLD) serves as a major cause of CLD with a rising annual prevalence. Additionally, iron overload can be both a cause and effect of CLD with a negative synergistic effect when combined with NAFLD. The development of state-of-the-art multiparametric MR solutions has led to a change in the diagnostic paradigm in CLD, shifting from traditional liver biopsy to innovative non-invasive methods for providing accurate and reliable detection and quantification of the disease burden. Novel imaging biomarkers such as MRI-PDFF for fat, R2 and R2* for iron, and liver stiffness for fibrosis provide important information for diagnosis, surveillance, risk stratification, and treatment. In this article, we provide a concise overview of the MR concepts and techniques involved in the detection and quantification of liver fat, iron, and fibrosis including their relative strengths and limitations and discuss a practical abbreviated MR protocol for clinical use that integrates these three MR biomarkers into a single simplified MR assessment. Multiparametric MR techniques provide accurate and reliable non-invasive detection and quantification of liver fat, iron, and fibrosis. These techniques can be combined in a single abbreviated MR "Triple Screen" assessment to offer a more complete metabolic imaging profile of CLD.

Radiomics-based approaches outperform visual analysis for differentiating lipoma from atypical lipomatous tumors: a review.

BACKGROUND: Differentiating atypical lipomatous tumors (ALTs) and well-differentiated liposarcomas (WDLs) from benign lipomatous lesions is important for guiding clinical management, though conventional visual analysis of these lesions is challenging due to overlap of imaging features. Radiomics-based approaches may serve as a promising alternative and/or supplementary diagnostic approach to conventional imaging. PURPOSE: The purpose of this study is to review the practice of radiomics-based imaging and systematically evaluate the literature available for studies evaluating radiomics applied to differentiating ALTs/WDLs from benign lipomas. REVIEW: A background review of the radiomic workflow is provided, outlining the steps of image acquisition, segmentation, feature extraction, and model development. Subsequently, a systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and the grey literature was performed from inception to June 2022 to identify size studies using radiomics for differentiating ALTs/WDLs from benign lipomas. Radiomic models were shown to outperform conventional analysis in all but one model with a sensitivity ranging from 68 to 100% and a specificity ranging from 84 to 100%. However, current approaches rely on user input and no studies used a fully automated method for segmentation, contributing to interobserver variability and decreasing time efficiency. CONCLUSION: Radiomic models may show improved performance for differentiating ALTs/WDLs from benign lipomas compared to conventional analysis. However, considerable variability between radiomic approaches exists and future studies evaluating a standardized radiomic model with a multi-institutional study design and preferably fully automated segmentation software are needed before clinical application can be more broadly considered.

Reliability of ultrasound ovarian-adnexal reporting and data system amongst less experienced readers before and after training.

BACKGROUND: The 2018 ovarian-adnexal reporting and data system (O-RADS) guidelines are aimed at providing a system for consistent reports and risk stratification for ovarian lesions found on ultrasound. It provides key characteristics and findings for lesions, a lexicon of descriptors to communicate findings, and risk characterization and associated follow-up recommendation guidelines. However, the O-RADS guidelines have not been validated in North American institutions or amongst less experienced readers. AIM: To evaluate the diagnostic accuracy and inter-reader reliability of ultrasound O-RADS risk stratification amongst less experienced readers in a North American institution with and without pre-test training. METHODS: A single-center retrospective study was performed using 100 ovarian/adnexal lesions of varying O-RADS scores. Of these cases, 50 were allotted to a training cohort and 50 to a testing cohort via a non-randomized group selection process in order to approximately equal distribution of O-RADS categories both within and between groups. Reference standard O-RADS scores were established through consensus of three fellowship-trained body imaging radiologists. Three PGY-4 residents were independently evaluated for diagnostic accuracy and inter-reader reliability with and without pre-test O-RADS training. Sensitivity, specificity, positive predictive value, negative predictive value (NPV), and area under the curve (AUC) were used to measure accuracy. Fleiss kappa and weighted quadratic (pairwise) kappa values were used to measure inter-reader reliability. Statistical significance was P < 0.05. RESULTS: Mean patient age was 40 ± 16 years with lesions ranging from 1.2 to 22.5 cm. Readers demonstrated excellent specificities (85%-100% pre-training and 91%-100% post-training) and NPVs (89%-100% pre-training and 91-100% post-training) across the O-RADS categories. Sensitivities were variable (55%-100% pre-training and 64%-100% post-training) with malignant O-RADS 4 and 5 Lesions pre-training and post-training AUC values of 0.87-0.95 and 0.94-098, respectively (P < 0.001). Nineteen of 22 (86%) misclassified cases in pre-training were related to mischaracterization of dermoid features or wall/septation morphology. Fifteen of 17 (88%) of post-training misclassified cases were related to one of these two errors. Fleiss kappa inter-reader reliability was 'good' and pairwise inter-reader reliability was 'very good' with pre-training and post-training assessment (k = 0.76 and 0.77; and k = 0.77-0.87 and 0.85-0.89, respectively). CONCLUSION: Less experienced readers in North America achieved excellent specificities and AUC values with very good pairwise inter-reader reliability. They may be subject to misclassification of potentially malignant lesions, and specific training around dermoid features and smooth vs irregular inner wall/septation morphology may improve sensitivity.

Diagnostic accuracy and inter-reader reliability of the MRI Liver Imaging Reporting and Data System (version 2018) risk stratification and management system.

Background: Hepatocellular carcinoma (HCC) can be diagnosed non-invasively, provided certain imaging criteria are met. However, the recent Liver Imaging Reporting and Data System (LI-RADS) version 2018 has not been widely validated. Objectives: This study aimed to evaluate the diagnostic accuracy and reader reliability of the LI-RADS version 2018 lexicon amongst fellowship trained radiologists compared with an expert consensus reference standard. Method: This retrospective study was conducted between 2018 and 2020. A total of 50 contrast enhanced liver magnetic resonance imaging (MRI) studies evaluating focal liver observations in patients with cirrhosis, hepatitis B virus (HBV) or prior HCC were acquired. The standard of reference was a consensus review by three fellowship-trained radiologists. Diagnostic accuracy including sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV) and area under the curve (AUC) values were calculated per LI-RADS category for each reader. Kappa statistics were used to measure reader agreement. Results: Readers demonstrated excellent specificities (88% - 100%) and NPVs (85% - 100%) across all LI-RADS categories. Sensitivities were variable, ranging from 67% to 83% for LI-RADS 1, 29% to 43% for LI-RADS 2, 100% for LI-RADS 3, 70% to 80% for LI-RADS 4 and 80% to 84% for LI-RADS 5. Readers showed excellent accuracy for differentiating benign and malignant liver lesions with AUC values > 0.90. Overall inter-reader agreement was 'good' (kappa = 0.76, p < 0.001). Pairwise inter-reader agreement was 'very good' (kappa ≥ 0.90, p < 0.001). Conclusion: The LI-RADS version 2018 demonstrates excellent specificity, NPV and AUC values for risk stratification of liver observations by radiologists. Liver Imaging Reporting and Data System can reliably differentiate benign from malignant lesions when used in conjunction with corresponding LI-RADS management recommendations.

A review of 99mTc-sestamibi SPECT/CT for renal oncocytomas: A modified diagnostic algorithm.

99mTc-sestamibi SPECT/CT is a promising nuclear medicine imaging investigation for benign renal lesions such as renal oncocytomas. The purpose of this article is to i) review the current literature on 99mTc-sestamibi SPECT/CT, ii) to review to current application of 99mTc-sestamibi SPECT/CT for indeterminate renal lesion imaging, and iii) to discuss present limitations and areas for future research. The literature has been reviewed up to April 2022 for articles relating to the application of 99mTc-sestamibi SPECT/CT for benign renal lesions including a recently published systematic review and meta-analysis performed by the authors. One study evaluating 99mTc-sestamibi SPECT alone and five studies evaluating 99mTc-sestamibi SPECT/CT have been performed to date. 99mTc-sestamibi SPECT/CT demonstrates high sensitivity and specificity for detecting benign renal lesions, particularly renal oncocytomas. 99mTc-sestamibi SPECT/CT demonstrates near-perfect specificity for benign and low-grade renal lesions. The optimal quantified threshold ratio for tumor-to-background renal parenchyma radiotracer uptake for a positive result is > 0.6. In this article, we propose a modified diagnostic algorithm for small enhancing renal masses measuring 1-4 cm in which suspected benign lesions after conventional imaging are considered for 99mTc-sestamibi SPECT-CT. In this algorithm, positive studies can be monitored with active surveillance rather than requiring invasive biopsy and/or targeted therapy.

Tips for improving consistency of thyroid nodule interpretation with ACR TI-RADS.

Thyroid nodules are very common in the general population. Most are benign and even those that are malignant are typically slow-growing and do not require treatment. Overdiagnosis and overtreatment of thyroid nodules has resulted in significant healthcare costs. ACR TI-RADS was developed to address these concerns, and reduce the number of unnecessary biopsies and follow-up intervals. ACR TI-RADS offers a point-based risk stratification system centered on five sonographic features: consistency, echogenicity, shape, margins and echogenic foci. While the system has noticeable benefits and comparable accuracy with other available risk stratification systems (ATA, EU-TIRADS and K-TIRADS), there are inherent challenges relating to suboptimal inter-reader agreement. In this article, we include 10 educational tips that may be helpful to the ultrasound practitioner for improving the consistency of nodule interpretation with ACR TI-RADS.

Effect of training on resident inter-reader agreement with American College of Radiology Thyroid Imaging Reporting and Data System.

BACKGROUND: The American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) was introduced to standardize the ultrasound characterization of thyroid nodules. Studies have shown that ACR-TIRADS reduces unnecessary biopsies and improves consistency of imaging recommendations. Despite its widespread adoption, there are few studies to date assessing the inter-reader agreement amongst radiology trainees with limited ultrasound experience. We hypothesize that in PGY-4 radiology residents with no prior exposure to ACR TI-RADS, a statistically significant improvement in inter-reader reliability can be achieved with a one hour training session. AIM: To evaluate the inter-reader agreement of radiology residents in using ACR TI-RADS before and after training. METHODS: A single center retrospective cohort study evaluating 50 thyroid nodules in 40 patients of varying TI-RADS levels was performed. Reference standard TI-RADS scores were established through a consensus panel of three fellowship-trained staff radiologists with between 1 and 14 years of clinical experience each. Three PGY-4 radiology residents (trainees) were selected as blinded readers for this study. Each trainee had between 4 to 5 mo of designated ultrasound training. No trainee had received specialized TI-RADS training prior to this study. Each of the readers independently reviewed the 50 testing cases and assigned a TI-RADS score to each case before and after TI-RADS training performed 6 wk apart. Fleiss kappa was used to measure the pooled inter-reader agreement. The relative diagnostic performance of readers, pre- and post-training, when compared against the reference standard. RESULTS: There were 33 females and 7 males with a mean age of 56.6 ± 13.6 years. The mean nodule size was 19 ± 14 mm (range from 5 to 63 mm). A statistically significant superior inter-reader agreement was found on the post-training assessment compared to the pre-training assessment for the following variables: 1. "Shape" (k of 0.09 [slight] pre-training vs 0.67 [substantial] post-training, P < 0.001), 2. "Echogenic foci" (k of 0.28 [fair] pre-training vs 0.45 [moderate] post-training, P = 0.004), 3. 'TI-RADS level' (k of 0.14 [slight] pre-training vs 0.36 [fair] post-training, P < 0.001) and 4. 'Recommendations' (k of 0.36 [fair] pre-training vs 0.50 [moderate] post-training, P = 0.02). No significant differences between the pre- and post-training assessments were found for the variables 'composition', 'echogenicity' and 'margins'. There was a general trend towards improved pooled sensitivity with TI-RADS levels 1 to 4 for the post-training assessment while the pooled specificity was relatively high (76.6%-96.8%) for all TI-RADS level. CONCLUSION: Statistically significant improvement in inter-reader agreement in the assigning TI-RADS level and recommendations after training is observed. Our study supports the use of dedicated ACR TI-RADS training in radiology residents.