Report from the society of magnetic resonance angiography: clinical applications of 7T neurovascular MR in the assessment of intracranial vascular disease.

In recent years, ultra-high-field magnetic resonance imaging (MRI) applications have been rapidly increasing in both clinical research and practice. Indeed, 7-Tesla (7T) MRI allows improved depiction of smaller structures with high signal-to-noise ratio, and, therefore, may improve lesion visualization, diagnostic capabilities, and thus potentially affect treatment decision-making. Incremental evidence emerging from research over the past two decades has provided a promising prospect of 7T magnetic resonance angiography (MRA) in the evaluation of intracranial vasculature. The ultra-high resolution and excellent image quality of 7T MRA allow us to explore detailed morphological and hemodynamic information, detect subtle pathological changes in early stages, and provide new insights allowing for deeper understanding of pathological mechanisms of various cerebrovascular diseases. However, along with the benefits of ultra-high field strength, some challenges and concerns exist. Despite these, ongoing technical developments and clinical oriented research will facilitate the widespread clinical application of 7T MRA in the near future. In this review article, we summarize technical aspects, clinical applications, and recent advances of 7T MRA in the evaluation of intracranial vascular disease. The aim of this review is to provide a clinical perspective for the potential application of 7T MRA for the assessment of intracranial vascular disease, and to explore possible future research directions implementing this technique.

Vessel Wall Imaging in Cryptogenic Stroke.

Cryptogenic strokes are symptomatic cerebral ischemic infarcts without a clear etiology identified following standard diagnostic evaluation and currently account for 10% to 40% of stroke cases. Continued research is needed to identify and bridge gaps in knowledge of this stroke grouping. Vessel wall imaging has increasingly shown its utility in the diagnosis and characterization of various vasculopathies. Initial promising evidence suggests rational use of vessel wall imaging in stroke workup may unravel pathologies that otherwise would have been occult and further improve our understanding of underlying disease processes that can translate into improved patient outcomes and secondary stroke prevention.

Propagation Imaging in the Demonstration of Common Shear Wave Artifacts.

In this article, we describe our experience with shear wave propagation imaging (SWPI) as an adjunct to 2-dimensional (2D) shear wave elastography (SWE) in a cohort of patients being evaluated for diffuse liver disease. Two-dimensional SWE has been extensively studied in previous publications; however, 2D SWE using propagation images has not been widely described in the literature to date. We observed that when certain artifacts occurred on the color elastograms, highly characteristic changes to shear wave propagation contours were seen, which can help clarify the cause of the artifacts. To our knowledge, the use of SWPI to explain the etiology of artifacts has never been published before. The artifacts described in this article include the capsule reverberation artifact, penetration limitation or dropout artifact, artifact due to blood vessels, shadowing artifact, tissue motion artifact, and near-field distortion/precompression artifact. Hence, the purpose of this article is to show examples of common artifacts seen on 2D SWE as depicted on corresponding SWPI to demonstrate that both types of image displays are complementary to each other.

18F-Fluciclovine Uptake by an Incidentally Detected Hepatocellular Carcinoma in a Case of Biochemically Recurrent Prostate Cancer.

Prostate cancer is one of the most common cancers affecting men worldwide with a high recurrence rate following therapy. F-fluciclovine, is a US Food and Drug Administration-approved radiopharmaceutical for PET imaging in biochemically recurrent prostate cancer. It targets increased amino acid transporters in the cell membrane of cancer cells. We report a case of incidentally detected hepatocellular carcinoma showing F-fluciclovine uptake in a 71-year-old man with biochemically recurrent prostate cancer.

Utility of diffusion-weighted MR imaging in the diagnosis of placenta accreta spectrum abnormality.

PURPOSE: The aim of this study was to evaluate the utility of added DWI sequences as an adjunct to traditional MR imaging in the evaluation of abnormal placentation in patients with suspicion for placenta accreta spectrum abnormality or morbidly adherent placenta (MAP). MATERIALS AND METHODS: The study was approved by local ethics committee. The subjects included pregnant women with prenatal MRI performed between July 2013 to July 2015. All imaging was performed on a Philips 1.5T MR scanner using pelvic phased-array coil. Only T2-weighted and diffusion-weighted imaging (DWI) series were compiled for review. Two randomized imaging sets were created: set 1 included T2-weighted series only (T2W); set 2 included T2W with DWI series together (T2W + DWI). Three radiologists, blinded to history and pathology, reviewed the imaging, with 2 weeks of time between the two image sets. Sensitivity, specificity, and overall accuracy for MAP were calculated and compared between T2W only and T2W + DWI reads. Associations between imaging findings and invasion on pathology were tested using the Chi-squared test. Confidence scores, inter-reader agreement, and systematic differences were documented. RESULTS: A total of 17 pregnant women were included in the study. 8 cases were pathologically diagnosed with MAP. There were no significant differences in the diagnostic accuracy between T2W and T2W + DWI in the diagnosis of MAP in terms of overall accuracy (62.7% for T2W vs. 68.6% for T2W + DWI, p = 0.68), sensitivity (70.8% for T2W vs. 95.8% for T2W + DWI, p = 0.12), and specificity (55.6% for T2W vs. 44.4% for T2W + DWI, p = 0.49). There was no significant difference in the diagnostic confidence between the review of T2W images alone and the T2W + DWI review (mean 7.3 ± 1.8 for T2W vs. 7.5 ± 1.8 for T2W + DWI, p = 0.37). CONCLUSION: With the current imaging technique, addition of DWI sequence to the traditional T2W images cannot be shown to significantly increase the accuracy or reader confidence for diagnosis of placenta accreta spectrum abnormality. However, DWI does improve identification of abnormalities in the placental-myometrial interface.

Tricky Findings in Liver Transplant Imaging: A Review of Pitfalls With Solutions.

Orthotopic liver transplantation is the preferred treatment for end-stage liver disease. Imaging plays an important role in the follow-up of transplant recipients by identifying a variety of complications. Posttransplant liver imaging can be challenging with altered vascular and nonvascular postoperative findings closely mimicking pathologies. A thorough knowledge of these common imaging findings in a posttransplant liver is essential for the radiologist to avoid erroneous diagnoses and unnecessary workup. We focus on such imaging findings and provide tips to avoid misinterpretation.

Solid Tumors of the Mediastinum in Adults.

A wide spectrum of solid tumors can develop in the mediastinum of adults. Like for any other tumor evaluation, the location and morphology play equally important role for lesion characterization. Compartmentalizing the mediastinal masses greatly narrows the number of possible differential diagnosis. Cross sectional imaging mainly with computed tomography (CT) and magnetic resonance imaging (MRI) are the preferred modalities of choice as they can establish the presence, location and morphology of the lesion allowing to suggest a possible diagnosis.

PVNS or pseudo aneurysm: MRI-problem solving or misleading?

Pigmented villonodular synovitis (PVNS) is a benign neoplastic process affecting the synovium. Magnetic resonance imaging (MRI) is considered as the imaging modality of choice, where PVNS is seen as a soft tissue lesion affecting the synovium with characteristic hypointense signal on T2-weighted images (T2WI) and typically blooming on gradient echo (GRE) sequences. MRI can sometimes be misleading, with many non-neoplastic pathologies having a tendency of recurrent bleeding closely mimicking PVNS. We report a case  of pseudoaneurysm from posterior circumflex humeral artery, a branch of axillary artery, secondary to recurrent shoulder dislocation mimicking PVNS on MRI.

Ultrasound and Doppler features of Budd-Chiari syndrome in pediatric population.

Budd-Chiari syndrome (BCS) occurs as a result of hepatic venous outflow obstruction. In the pediatric population, the etiologies vary as compared with the adult population. Decompensation can occur faster in this set of patients. Ultrasound and Doppler represent important imaging modalities for diagnosing BCS in children. The imaging features differ depending upon the level of obstruction, acuteness of the condition, and secondary decompensation. Caudate lobe hypertrophy is a salient feature. Obstruction at the level of hepatic veins may be manifested by ostial narrowing, echogenic thrombus, and altered flow patterns in the form of turbulent flow, nonvisualization of the veins, or reversal of flow. Obstruction in the inferior vena cava may present as an echogenic web, membrane, or thrombus with turbulent flow to absent flow within depending upon the degree of luminal compromise. Collateral formation is an important distinctive feature of subacute and chronic BCS. Collaterals that develop may be of intrahepatic or extrahepatic type. Secondary signs of liver failure would be present in late stages. Understanding the clinical presentation and imaging features can help in achieving the correct diagnosis because an early diagnosis of the disease will impact patient management.

Hysterosalpingography and ultrasonography findings of female genital tuberculosis.

Genital tuberculosis (TB) is an important cause of female infertility in the world, especially in developing countries. Majority of infertility cases are due to involvement of the fallopian tubes (92%-100%), endometrial cavity (50%), and ovaries (10%-30%); cervical and vulvovaginal TB are uncommon. Genital TB has characteristic radiological appearances based on the stage of the disease process (acute inflammatory or chronic fibrotic) and the organ of involvement. Hysterosalpingography (HSG) and ultrasonography (US) remain the main imaging modalities used in the diagnosis of genital TB. HSG is the primary modality for evaluating uterine, fallopian tube, and peritubal involvement and also helps in evaluating tubal patency. US, on the other hand, allows simultaneous evaluation of ovarian and extrapelvic involvement.