I saw the "hook" sign of median arcuate ligament syndrome.

The hook sign is a radiologic finding best appreciated on a sagittal view of the celiac artery with computed tomography (CT) that indicates compression of the celiac artery. It refers to the hooked-shape of the proximal celiac artery caused by extrinsic compression by the median arcuate ligament. When seen in a patient with concurrent abdominal symptoms, it suggests median arcuate ligament syndrome (MALS). We saw the sign in a 15-year-old male via duplex ultrasonography and abdominal CT. He underwent laparoscopic release of the median arcuate ligament and had full resolution of his symptoms at follow-up.

IgG4 porta-hepatis pseudotumor mimicking a hilar cholangiocarcinoma.

A 60-year-old female with a BRCA2 mutation and a history of breast cancer presented with diffuse abdominal pain and elevated liver enzymes. Imaging revealed a porta-hepatis mass, prompting consideration of hilar cholangiocarcinoma or breast cancer metastasis. Further investigation including biopsy and 18F-fluorodeoxyglucose positron emission tomography/computed tomography findings were inconsistent with malignancy, leading to investigation of non-neoplastic causes. Elevated IgG4 levels suggested IgG4-related disease, a mass-forming fibroinflammatory condition. This case demonstrates IgG4-related disease exclusively impacting the portal vein and underscores the importance of considering IgG4-related disease in the differential diagnosis of hepatic masses.

Post-operative complications of cholecystectomy: what the radiologist needs to know.

Cholecystectomy is one of the most performed surgical procedures. The safety of this surgery notwithstanding, the sheer volume of operations results in a notable incidence of post-cholecystectomy complications. Early and accurate diagnosis of such complications is essential for timely and effective management. Imaging techniques are critical for this purpose, aiding in distinguishing between expected postsurgical changes and true complications. This review highlights current knowledge on the indications for cholecystectomy, pertinent surgical anatomy and surgical technique, and the recognition of anatomical variants that may complicate surgery. The article also outlines the roles of various imaging modalities in identifying complications, the spectrum of possible postsurgical anatomical changes, and the implications of such findings. Furthermore, we explore the array of complications that can arise post-cholecystectomy, such as biliary system injuries, gallstone-related issues, vascular complications, and the formation of postsurgical collections. Radiologists should be adept at identifying normal and abnormal postoperative findings to guide patient management effectively.

I saw the Venetian blind sign.

The Venetian blind sign is a radiologic sign seen on pelvic ultrasound. It is classically associated with adenomyosis and, less commonly, uterine fibroids. It appears as alternating vertical stripes of hyperechoic and hypoechoic bands, resembling the horizontal slatted window blinds for which it is named.

Comprehensive review of pericardial diseases using different imaging modalities.

Pericardial abnormalities are common cardiovascular disease entity, which are encountered in various clinical settings. Imaging plays an integral role in evaluation of pericardial abnormalities. The appropriate use of multiple imaging modalities is crucial to initiate the diagnosis and guide the referring providers to establish a management plan. Echocardiography (echo) is the initial imaging modality of choice. Computed tomography (CT) and magnetic resonance imaging (MRI) are complementary imaging tools with better tissue characterization. Pericardial abnormalities include pericardial effusion, pericarditis, pericardial constriction, tamponade, pneumopericardium, pericardial rupture, fistulas, congenital abnormalities, and pericardial tumors. Pericardial effusion is a common clinical entity, where there is accumulation of fluid in the pericardial sac. Pericarditis can be acute, incessant, chronic, or recurrent. Pericardial thickening or enhancement are the main CT findings in acute pericarditis. Pericardial constriction results into diastolic heart failure. Differentiating constrictive pericarditis from restrictive cardiomyopathy is important, since these conditions can present with similar clinical and hemodynamic findings and both have different management. Right atrial or right ventricular compression by the pericardial sac contents should raise the suspicion for tamponade. Immediate pericardiocentesis to release the elevated intra-pericardial pressure can be lifesaving. Pericardial rupture is a serious condition that can occur after trauma and can lead to cardiac herniation. The main purpose of this article is to do a comprehensive review of the imaging appearance of pericardial diseases on different imaging modalities and establish a structured diagnostic approach for pericardial diseases to appropriately guide management.

An Algorithmic Approach to Complex Fetal Abdominal Wall Defects.

OBJECTIVE. The purpose of this article is to describe the imaging findings associated with complex fetal abdominal wall defects and provide an algorithmic method for arriving at a final diagnosis. CONCLUSION. Fetal ventral abdominal wall defects are a complex group of conditions with a broad spectrum of associated multisystem anomalies and manifestations. Correct characterization and classification of these defects require not only familiarity with imaging findings but also a systematic approach to avoid diagnostic confusion.

Radiologist's Guide to Diagnosis of Fetal Cardiac Anomalies on Prenatal Ultrasound Imaging.

Congenital cardiac anomalies are a common finding during prenatal anatomical survey ultrasound examination. Cardiac anomalies are a major cause of prenatal and neonatal mortality and morbidity. If the anomaly is not lethal, most would require surgical correction. Therefore, early recognition of these abnormalities is essential for parental counseling and delivery planning, as well as analysis of neonatal treatment options. Although prenatal ultrasound plays an important role in identification of such anomalies, diagnosis and interpretation of imaging findings require familiarity and knowledge of the common imaging features. In this article, we provide a comprehensive review of ultrasound appearance of common fetal cardiac anomalies.

CT Detectability of Small Low-Contrast Hypoattenuating Focal Lesions: Iterative Reconstructions versus Filtered Back Projection.

Purpose To investigate performance in detectability of small (≤1 cm) low-contrast hypoattenuating focal lesions by using filtered back projection (FBP) and iterative reconstruction (IR) algorithms from two major CT vendors across a range of 11 radiation exposures. Materials and Methods A low-contrast detectability phantom consisting of 21 low-contrast hypoattenuating focal objects (seven sizes between 2.4 and 10.0 mm, three contrast levels) embedded into a liver-equivalent background was scanned at 11 radiation exposures (volume CT dose index range, 0.5-18.0 mGy; size-specific dose estimate [SSDE] range, 0.8-30.6 mGy) with four high-end CT platforms. Data sets were reconstructed by using FBP and varied strengths of image-based, model-based, and hybrid IRs. Sixteen observers evaluated all data sets for lesion detectability by using a two-alternative-forced-choice (2AFC) paradigm. Diagnostic performances were evaluated by calculating area under the receiver operating characteristic curve (AUC) and by performing noninferiority analyses. Results At benchmark exposure, FBP yielded a mean AUC of 0.79 ± 0.09 (standard deviation) across all platforms which, on average, was approximately 2% lower than that observed with the different IR algorithms, which showed an average AUC of 0.81 ± 0.09 (P = .12). Radiation decreases of 30%, 50%, and 80% resulted in similar declines of observer detectability with FBP (mean AUC decrease, -0.02 ± 0.05, -0.03 ± 0.05, and -0.05 ± 0.05, respectively) and all IR methods investigated (mean AUC decrease, -0.00 ± 0.05, -0.04 ± 0.05, and -0.04 ± 0.05, respectively). For each radiation level and CT platform, variance in performance across observers was greater than that across reconstruction algorithms (P = .03). Conclusion Iterative reconstruction algorithms have limited radiation optimization potential in detectability of small low-contrast hypoattenuating focal lesions. This task may be further complicated by a high degree of variation in radiologists' performances, seemingly exceeding real performance differences among reconstruction algorithms. © RSNA, 2018 Online supplemental material is available for this article.