A Multicenter Assessment of Interreader Reliability of LI-RADS Version 2018 for MRI and CT.

Background Various limitations have impacted research evaluating reader agreement for Liver Imaging Reporting and Data System (LI-RADS). Purpose To assess reader agreement of LI-RADS in an international multicenter multireader setting using scrollable images. Materials and Methods This retrospective study used deidentified clinical multiphase CT and MRI and reports with at least one untreated observation from six institutions and three countries; only qualifying examinations were submitted. Examination dates were October 2017 to August 2018 at the coordinating center. One untreated observation per examination was randomly selected using observation identifiers, and its clinically assigned features were extracted from the report. The corresponding LI-RADS version 2018 category was computed as a rescored clinical read. Each examination was randomly assigned to two of 43 research readers who independently scored the observation. Agreement for an ordinal modified four-category LI-RADS scale (LR-1, definitely benign; LR-2, probably benign; LR-3, intermediate probability of malignancy; LR-4, probably hepatocellular carcinoma [HCC]; LR-5, definitely HCC; LR-M, probably malignant but not HCC specific; and LR-TIV, tumor in vein) was computed using intraclass correlation coefficients (ICCs). Agreement was also computed for dichotomized malignancy (LR-4, LR-5, LR-M, and LR-TIV), LR-5, and LR-M. Agreement was compared between research-versus-research reads and research-versus-clinical reads. Results The study population consisted of 484 patients (mean age, 62 years ± 10 [SD]; 156 women; 93 CT examinations, 391 MRI examinations). ICCs for ordinal LI-RADS, dichotomized malignancy, LR-5, and LR-M were 0.68 (95% CI: 0.61, 0.73), 0.63 (95% CI: 0.55, 0.70), 0.58 (95% CI: 0.50, 0.66), and 0.46 (95% CI: 0.31, 0.61) respectively. Research-versus-research reader agreement was higher than research-versus-clinical agreement for modified four-category LI-RADS (ICC, 0.68 vs 0.62, respectively; P = .03) and for dichotomized malignancy (ICC, 0.63 vs 0.53, respectively; P = .005), but not for LR-5 (P = .14) or LR-M (P = .94). Conclusion There was moderate agreement for LI-RADS version 2018 overall. For some comparisons, research-versus-research reader agreement was higher than research-versus-clinical reader agreement, indicating differences between the clinical and research environments that warrant further study. © RSNA, 2023 Supplemental material is available for this article. See also the editorials by Johnson and Galgano and Smith in this issue.

Multilocular Cystic Nephroma: A Systematic Literature Review of the Radiologic and Clinical Findings.

OBJECTIVE: The objective of our study was to systematically summarize the published evidence of demographic, clinical, diagnostic imaging, and therapeutic characteristics of patients with multilocular cystic nephroma (MLCN). CONCLUSION: Cross-sectional imaging evaluation is important for suggesting the diagnosis of MLCN but has several limitations. The number of radical nephrectomies reported for MLCN encourages discussion concerning the utility of percutaneous presurgical biopsy and frozen-section intraoperative biopsy as a more conservative diagnostic approach.

Nonvascular post-liver transplantation complications: from US screening to cross-sectional and interventional imaging.

Orthotopic liver transplantation is becoming an increasingly routine procedure for a variety of benign and malignant diseases of the liver and biliary system. Continued improvements in surgical techniques and post-transplantation immunosuppression regimens have resulted in better graft and patient survival. A number of potentially treatable nonvascular complications of liver transplantation are visible at imaging, and accurate diagnosis of these complications allows patients to benefit from potential treatment options. Biliary complications include stricture (anastomotic and nonanastomotic), leak, biloma formation, and development of intraductal stones. Pathologic conditions, including hepatitis C infection, hepatocellular carcinoma, hepatic steatosis, and primary sclerosing cholangitis, may recur after liver transplantation. Transplant patients are at increased risk for developing de novo malignancy, including post-transplantation lymphoproliferative disorder, which results from immunosuppression. Patients are also at increased risk for systemic infection from immunosuppression, and patients with hepatic artery and biliary complications are at increased risk for liver abscess. Transplant recipients are typically followed with serial liver function testing; abnormal serum liver function test results may be the first indication that there is a problem with the transplanted liver. Ultrasonography is typically the first imaging test performed to try to identify the cause of abnormal liver function test results. Computed tomography, magnetic resonance imaging, angiography, and/or cholangiography may be necessary for further evaluation. Accurately diagnosing nonvascular complications of liver transplantation that are visible at imaging is critically important for patients to benefit from appropriate treatment.

DICOM gray-scale standard display function: clinical diagnostic accuracy of chest radiography in medical-grade gray-scale and consumer-grade color displays.

OBJECTIVE: The purpose of this study was to compare the diagnostic accuracy achieved with and without the calibration method established by the DICOM standard in both medical-grade gray-scale displays and consumer-grade color displays. MATERIALS AND METHODS: This study involved 76 cases, six radiologists, three displays, and two display calibrations for a total of 2736 observations in a multireader-multicase factorial design. The evaluated conditions were interstitial opacities, pneumothorax, and nodules. CT was adopted as the reference standard. One medical-grade gray-scale display and two consumer-grade color displays were evaluated. Analyses of ROC curves, diagnostic accuracy (measured as AUC), accuracy of condition classification, and false-positive and false-negative rate comparisons were performed. The degree of agreement between readers was also evaluated. RESULTS: No significant differences in image quality perception by the readers in the presence or absence of calibration were observed. Similar forms of the ROC curves were observed. No significant differences were detected in the observed variables (diagnostic accuracy, accuracy of condition classification, false-positive rates, false-negative rates, and image-quality perception). Strong agreement between readers was also determined for each display with and without calibration. CONCLUSION: For the chest conditions and selected observers included in this study, no significant differences were observed between the three evaluated displays with respect to accuracy performance with and without calibration.

Posttransplantation lymphoproliferative disease: proposed imaging classification.

Posttransplantation lymphoproliferative disease (PTLD) is the second most common tumor in adult transplant recipients. Most cases of PTLD are attributed to Epstein-Barr virus. Decreased levels of immunosurveillance against this tumor virus as a result of immunosuppressive regimens are thought to account for most cases of PTLD. Histologically, PTLD ranges from relatively benign lymphoid hyperplasia to poorly differentiated lymphoma, and tissue sampling is required to establish the subtype. The frequency of PTLD varies depending on the type of allograft and immunosuppressive regimen. PTLD has a bimodal manifestation, with most cases occurring within the first year after transplantation and a second peak occurring 4-5 years after transplantation. Patients are often asymptomatic or present with nonspecific symptoms, and a mass visible at imaging may be the first clue to the diagnosis. Imaging plays an important role in identifying the presence of disease, guiding tissue sampling, and evaluating response to treatment. The appearance of PTLD at imaging can vary. It may be nodal or extranodal. Extranodal disease may involve the gastrointestinal tract, solid organs, or central nervous system. Solid organ lesions may be solitary or multiple, infiltrate beyond the organ margins, and obstruct organ outflow. Suggestive imaging findings should prompt tissue sampling, because knowledge of the PTLD subtype is imperative for appropriate treatment. Treatment options include reducing immunosuppression, chemotherapy, radiation therapy, and surgical resection of isolated lesions.

Evaluation of three pneumothorax size quantification methods on digitized chest X-ray films using medical-grade grayscale and consumer-grade color displays.

This study focused on the effects of pneumothorax size quantification in digital radiology environments when a quantification method is selected according to the radiologist's criteria. The objective of this study was to assess the effects of factors, including the radiologist (with different experience), displays (medical-grade and consumer-grade displays), or display calibration, on the Rhea, Collins, and Light quantification methods. This study used a factorial design with 76 cases, including 16 pneumothorax cases observed by six radiologists on three displays with and without the DICOM standard calibration. The gold standard was established by two radiologists by using computed tomography. Analysis of variance (ANOVA) was performed on the pneumothorax sizes. For the three quantifications methods, none of the evaluated factors were significant. We conclude that radiologists, displays, and calibration do not significantly affect the quantification of pneumothorax size in different digital radiology environments.

Diagnostic accuracy of digitized chest X-rays using consumer-grade color displays for low-cost teleradiology services: a multireader-multicase comparison.

INTRODUCTION: In teleradiology services and in hospitals, the extensive use of visualization displays requires affordable devices. The purpose of this study was to compare three differently priced displays (a medical-grade grayscale display and two consumer-grade color displays) for image visualization of digitized chest X-rays. MATERIALS AND METHODS: The evaluated conditions were interstitial opacities, pneumothorax, and nodules using computed tomography as the gold standard. The comparison was accomplished in terms of receiver operating characteristic (ROC) curves, the diagnostic power measured as the area under ROC curves, accuracy in conditions classification, and main factors affecting accuracy, in a factorial study with 76 cases and six radiologists. RESULTS: The ROC curves for all of the displays and pathologies had similar shapes and no differences in diagnostic power. The proportion of cases correctly classified for each display was greater than 71.9%. The correctness proportions of the three displays were different (p<0.05) only for interstitial opacities. The evaluation of the main factors affecting these proportions revealed that the display factor was not significant for either nodule size or pneumothorax size (p>0.05). CONCLUSIONS: Although the image quality variables showed differences in the radiologists' perceptions of the image quality of the three displays, significant differences in the accuracy did not occur. The main effect on the variability of the proportions of correctly classified cases did not come from the display factor. This study confirms previous findings that medical-grade displays could be replaced by consumer-grade color displays with the same image quality.

Aberrant Right and Left Gastric Veins as a Cause of Hepatic Pseudolesions: A Report of Three Cases.

The complex structure of the liver and its elaborate hemodynamics can cause hepatic pseudolesions on contrast-enhanced imaging, making the interpretation of diagnostic liver imaging challenging. Aberrant gastric veins are rare; most of their epidemiology data comes from small single-center studies. While current literature suggests that pseudolesions originating from aberrant gastric veins mainly present as hyperdense defects, some cases can also show up as hypodense, as shown in these cases. Differences in flow rates between the portal and aberrant veins and the timing of the scans could explain this contradiction. Identifying aberrant gastric veins on cross-sectional imaging is crucial because they could be misdiagnosed as liver lesions, granting further unnecessary workups or invasive procedures. Aberrant gastric veins can also act as pathways for the spread of gastric cancer. This manuscript presents one aberrant right gastric vein and two aberrant left gastric veins causing hepatic pseudolesions.

Carcinoma of the rete testis: A rare testicular tumor.

Carcinoma of the rete testis is a rare malignant tumor which frequently occurs in middle-aged to older patients and has an aggressive biological behavior. We present the case of a 57-year-old man who presented with an ill-defined mass in the right testicle. The patient underwent a radical orchidectomy. Microscopic evaluation showed a neoplasm displaying a complex papillary-cystic architecture, infiltrating the testicular parenchyma. An in situ proliferation of neoplastic cells, with nuclear stratification and scanty cytoplasm was seen at the periphery, within the channels of the rete testis. The tumor infiltrated the tunica albuginea focally without disrupting it completely. Immunohistochemistry was positive for AE1/AE3, CK7, CK34ßE12, D2-40, and PAX8. Imaging studies presented no evidence of metastatic disease. These findings are those of a primary rete testis carcinoma. The transition between benign and neoplastic rete testis epithelium served as a helpful diagnostic clue. Metastatic carcinomas from other sites were considered in the differential diagnosis.

Cirrhosis-associated hepatocellular nodules: correlation of histopathologic and MR imaging features.

Cirrhotic livers are characterized by advanced fibrosis and the formation of hepatocellular nodules, which are classified histologically as either (a) regenerative lesions (eg, regenerative nodules, lobar or segmental hyperplasia, focal nodular hyperplasia) or (b) dysplastic or neoplastic lesions (eg, dysplastic foci and nodules, hepatocellular carcinomas). The differentiation of these lesions is important because regenerative nodules are benign, whereas dysplastic and neoplastic nodules are premalignant and malignant, respectively. However, their accurate characterization may be difficult even at histopathologic analysis. Differential diagnosis may be facilitated by comparing the clinical and pathologic findings with radiologic imaging features; in particular, nodule size, vascularity, hepatocellular function, and Kupffer cell density assessed at magnetic resonance (MR) imaging are suggestive of the correct diagnosis. MR imaging is more useful than computed tomography for such assessments because it provides better soft-tissue contrast and a more nuanced depiction of different tissue properties. Moreover, a wider variety of contrast agents is available for use in MR imaging. Familiarity with the MR imaging characteristics of cirrhosis-associated hepatocellular nodules is therefore important for optimal diagnosis and management of cirrhotic disease.

Fatty liver: imaging patterns and pitfalls.

Fat accumulation is one of the most common abnormalities of the liver depicted on cross-sectional images. Common patterns include diffuse fat accumulation, diffuse fat accumulation with focal sparing, and focal fat accumulation in an otherwise normal liver. Unusual patterns that may cause diagnostic confusion by mimicking neoplastic, inflammatory, or vascular conditions include multinodular and perivascular accumulation. All of these patterns involve the heterogeneous or nonuniform distribution of fat. To help prevent diagnostic errors and guide appropriate work-up and management, radiologists should be aware of the different patterns of fat accumulation in the liver, especially as they are depicted at ultrasonography, computed tomography, and magnetic resonance imaging. In addition, knowledge of the risk factors and the pathophysiologic, histologic, and epidemiologic features of fat accumulation may be useful for avoiding diagnostic pitfalls and planning an appropriate work-up in difficult cases.

MR contrast agents for liver imaging: what, when, how.

The major classes of contrast agents currently used for magnetic resonance (MR) imaging of the liver include extracellular agents (eg, low-molecular-weight gadolinium chelates), reticuloendothelial agents (eg, ferumoxides), hepatobiliary agents (eg, mangafodipir), blood pool agents, and combined agents. Mechanisms of action, dosage, elimination, toxic effects, indications for use, and MR imaging technical considerations vary according to class. Gadolinium chelates are the most widely used. Ferumoxides are a useful adjunct for detection of hepatocellular carcinoma, particularly when used in combination with gadolinium to achieve improved lesion-to-liver contrast over that achievable with gadolinium alone. Mangafodipir is a prototype hepatobiliary agent that is taken up by lesions with functioning hepatocytes. It may be used for MR cholangiography as well as liver imaging. Although mangafodipir is no longer commercially available in the United States, it is currently marketed and used in Europe. Blood pool agents have not yet been approved for human use in the United States. However, a new combined MR contrast agent, gadobenate dimeglumine, recently was approved, and other agents are in various stages of development.

Abdominal wall hernias: imaging features, complications, and diagnostic pitfalls at multi-detector row CT.

Abdominal wall hernias are a common imaging finding in the abdomen and may be complicated by strangulation, incarceration, or trauma. Because of the risk of developing complications, most abdominal wall hernias are surgically repaired, even if asymptomatic. However, post-surgical complications are also common and include hernia recurrence, infected and noninfected fluid collections, and complications related to prosthetic material. Multi-detector row computed tomography (CT) with its multiplanar capabilities is particularly useful for the evaluation of unrepaired and surgically repaired abdominal wall hernias. Multi-detector row CT provides exquisite anatomic detail of the abdominal wall, thereby allowing accurate identification of wall hernias and their contents, differentiation of hernias from other abdominal masses (tumors, hematomas, abscesses), and detection of pre- or postoperative complications. These findings improve the communication of imaging results to clinicians and help optimize treatment planning. Knowledge of multi-detector row CT findings in unrepaired and surgically repaired abdominal wall hernias and their complications is essential for making the correct diagnosis and may help guide clinical management.

Portal biliopathy: imaging manifestations on multidetector computed tomography and magnetic resonance imaging.

Portal biliopathy refers to biliary abnormalities secondary to extrahepatic portal vein obstruction and cavernous transformation and is caused by vascular compression from peribiliary collateral vessels, producing segmental stenoses of the common bile duct and abnormal liver function test (LFT) results. A review of imaging studies yielded 18 patients with abnormal LFT results, biliary tract dilatation, and extrahepatic portal vein obstruction with cavernous transformation. Multidetector computed tomography and magnetic resonance imaging showed biliary stenotic segments in 11 patients secondary to extrinsic compression from enlarged peribiliary collaterals. Clinical and imaging follow-up demonstrated improvement in LFT results with minimal decrease in bile duct dilatation, eliminating percutaneous or endoscopic biliary intervention.

Liver fibrosis: noninvasive diagnosis with double contrast material-enhanced MR imaging.

PURPOSE: To retrospectively evaluate the accuracy of double contrast material-enhanced (hereafter double-enhanced) magnetic resonance (MR) imaging depiction of hepatic fibrosis, with histopathologic analysis findings as the reference standard. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant study and waived the requirement for informed consent. One hundred one patients (58 men, 43 women; mean age +/- standard deviation, 52 years +/- 10) who underwent double-enhanced MR imaging with superparamagnetic iron oxide (SPIO)-enhanced and double-enhanced spoiled gradient-echo (SPGR) sequences between 2001 and 2004 and had a reliable reference standard for the diagnosis of liver fibrosis were included. Two blinded MR radiologists retrospectively scored qualitative (reticulation, nodularity, and total scores) and quantitative (contrast-to-noise ratio between hyperintense and hypointense liver regions, coefficient of variation, and noise-corrected coefficient of variation) liver texture features on MR images in consensus. The image scores for patients with advanced (METAVIR fibrosis score >/= 3) versus those for patients with mild (METAVIR score

Spinal CT-guided interventional procedures for management of chronic back pain.

PURPOSE: Image-guided interventional procedures have arisen as an alternative for management of back pain, with controversial indications and efficacy. This study describes the technique, clinical impact, and complications of computed tomography (CT)-guided infiltrations for the management of chronic back pain. MATERIALS AND METHODS: One hundred eleven patients with chronic back pain treated with CT-guided infiltrations were studied prospectively. Procedures performed included nerve root, facet joint, epidural, and sacroiliac joint blocks. Pain intensity was evaluated with use of a visual analog scale. RESULTS: Two hundred twenty-two infiltrations were performed in 111 consecutive patients. After 18 months of follow-up, pain improvement lasted for a mean duration of 9 months and the complication rate was less than 1%. Moderate to good pain response was seen in 95% of followed patients and 4% of patients required surgery. CONCLUSION: Spinal CT-guided infiltration constitutes an effective therapy for chronic back pain. This series confirms a low complication rate, good response, and high therapeutic value.

Evaluación por imágenes de las neoplasias peritoneales primarias y secundarias / Multimodality imaging evaluation of primary and secondary peritoneal malignancies

En este artículo se revisa la anatomía peritoneal normal en diferentes modalidades de imágenes seccionales. Serán expuestas las definiciones y características demográficas e imaginológicas de las patologías neoplásicas primaria y secundaria que involucran el peritoneo, para la adecuada evaluación de pacientes en quienes se sospecha clínicamente patología peritoneal.

This manuscript reviews normal peritoneal anatomy as seen on different cross sectional imaging modalities. Definition, demographic and imaging features of primary and secondary neoplastic pathology involving the peritoneum are discussed.