Cerebral venous thrombosis is a relatively uncommon but serious neurologic disorder that is potentially reversible with prompt diagnosis and appropriate medical care. Because the possible causal factors and clinical manifestations of this disorder are many and varied, imaging plays a primary role in the diagnosis. Magnetic resonance (MR) imaging, unenhanced computed tomography (CT), unenhanced time-of-flight MR venography, and contrast material-enhanced MR venography and CT venography are particularly useful techniques for detecting cerebral venous and brain parenchymal changes that may be related to thrombosis. To achieve an accurate diagnosis, it is important to have a detailed knowledge of the normal venous anatomy and variants, the spectrum of findings (venous sinus thrombi and recanalization, parenchymal diffusion or perfusion changes or hemorrhage), other potentially relevant conditions (deep venous occlusion, isolated cortical venous thrombosis, idiopathic intracranial hypertension), and potential pitfalls in image interpretation.

Imaging of cerebral venous thrombosis : Current techniques, spectrum of findings, and diagnostic pitfalls. Commentary and Authors' reply

Society of Interventional Radiology Position Statement on Catheter-Directed Therapy for Acute Pulmonary Embolism.

Case report: A first case of flaxseed-induced anaphylaxis in Korea.

The objective of this study is to determine, by using rigorous methods, if pulmonary perfusion defects were detectable by ventilation-perfusion scintigraphy after percutaneous thrombolysis of clotted hemodialysis access grafts. Thirteen patients were studied. Four patients underwent pharmacomechanical thrombolysis with urokinase and the remainder had mechanical thrombolysis alone. Pre- and postthrombolysis scintigraphic studies were performed on all patients. Perfusion defects were described as vascular (well-defined borders confined to segmental boundaries) or nonvascular. Vascular defects were graded by severity (0 to 3) and area (0 to 3) for each involved segment. Nonvascular defects were graded by severity (0 to 1) and area (0 to 1). Two experienced readers evaluated the scans blinded to each other's results and all other clinical data, including thrombolysis outcomes. Twelve patients did not have any significant worsening of their perfusion defect scores postthrombolysis. In only one patient did a study show a new nonvascular perfusion defect with a matching ventilation abnormality. The defect was believed to be caused by mucus plugging. The patient had no evidence of pulmonary embolism. Our study suggests emboli that resulted from the pharmacomechanical or mechanical thrombolysis procedure were either small, underwent lysis before impacting the lung, or were below the limit of detection of ventilation-perfusion scintigraphy.

Pulmonary Clot Burden After Percutaneous Thrombolysis of Clotted Hemodialysis Access Grafts

Acute Perioperative Pulmonary Embolism-Management Strategies and Outcomes.

Acute headache is a common symptom and is reported by approximately 2%-4% of patients who present to the emergency department. Many abnormalities manifest with headache as the first symptom, and it is crucial to obtain a patient's complete clinical history for correct diagnosis. Headache onset, duration, and severity; risk factors such as hypertension, immunosuppression, or malignancy; and the presence of focal neurologic deficits or systemic symptoms may aid the radiologist in deciding whether imaging is appropriate and which modality to choose. Imaging findings are more likely to be abnormal in patients with a "thunderclap" headache than in those with headaches of lesser severity. The causes of headache in the emergency setting are various. They may manifest at imaging as subarachnoid hemorrhage (ruptured aneurysm, reversible vasoconstriction syndrome, or pituitary apoplexy), parenchymal hemorrhage (hypertension, ruptured arteriovenous malformation, cerebral amyloid angiopathy, dural arteriovenous fistula, or sinus thrombosis), or parenchymal edema (posterior reversible encephalopathy syndrome, reversible cerebral vasoconstriction syndrome, sinus thrombosis, or encephalitis). Alterations in intracranial pressure that are related to idiopathic intracranial hypertension or spontaneous intracranial hypotension and prior lumbar puncture or epidural injection may manifest with specific imaging findings. With accumulating knowledge of disease pathophysiology, radiologists have started to play a more central role in making the correct diagnosis. This article reviews multiple causes of acute headache and their characteristic appearances at multimodality imaging and familiarizes the reader with current concepts in imaging.Online supplemental material is available for this article.©RSNA, 2019.

https://pubs.rsna.org/doi/pdf/10.1148/rg.2019190017

Acute Headache in the Emergency Setting.

Hemodialysis catheters (HDCs) are an essential part of kidney replacement therapy. While these catheters are considered only the bridge to long-term vascular access such as arteriovenous fistulas and grafts, they are associated with significant morbidity and mortality and subsequent increased health care expenditures. However, despite these risks, a large proportion of end stage kidney disease population initiates dialysis using these catheters. The pathogenicity of HDCs stems from its invasive nature to the venous vasculature tree resulting in both mechanical and infectious complications. Therefore, the wide use these catheters in dialysis population and the associated complications necessitated continuous innovations in the catheter material, design, and placement techniques. This review provides an update on the catheter types, catheter tip designs, and the new technologies and innovations aimed to improve the catheter functionality and mitigate its related complications.

Hemodialysis Catheters: Update on Types, Outcomes, Designs and Complications.

Re: Liver tumor ablation in difficult locations: Microwave ablation of perivascular and subdiaphragmatic hepatocellular carcinoma.

Purpose Catheter-directed thrombolysis (CDT) is an emerging, minimally invasive treatment for patients with massive and submassive pulmonary embolism (PE). The value of follow-up pulmonary angiography for evaluating improvement after CDT is limited by a paucity of large studies assessing its utility and role for additional intervention. The purpose of our study was to assess the role of next-day pulmonary angiography for CDT in patients with acute massive and submassive PE undergoing continuous pulmonary arterial pressure monitoring, and secondarily, determine factors that are correlated with a need for further therapy. Methods Patients who underwent CDT from 2006 to 2016 for massive and submassive PE were reviewed. Patient demographics, comorbidities, preprocedural lab results, noninvasive hemodynamic studies, and technical variables were recorded. Among patients receiving next-day angiography, those requiring further therapy, defined as continued CDT beyond the standard 24 hours (with or without catheter repositioning or exchange) and/or mechanical or suction thrombectomy were contrasted with those not requiring additional therapy to assess for the role of angiography and patient factors that correlate with need for further therapy. Results Thirty-two patients underwent CDT for massive (n=14) and submassive (n=18) PE. Eighteen (56.3%) were male, 14 (43.7%) were Caucasian, 18 (56.3%) were African-American, with a mean age of 66.2 years (range, 26-87 years). Of the 27 (84.4%) patients that underwent next-day pulmonary angiography, 16 (59.3%) did not require additional therapy and 11 (40.7%) did require additional therapy. Additional therapy included extended CDT beyond 24 hours (n=4), mechanical/suction thrombectomy (n=5), or both extended CDT and mechanical/suction thrombectomy (n=2). Younger age (50.1 vs. 62.2 years, P = 0.039) was correlated with a need for further therapy. Initial (40.7 vs. 34.8 mmHg, P = 0.248), next-day (31.5 vs. 26.3 mmHg, P = 0.259), and interval change (4.6 vs. 8.0 mmHg, P = 0.669) in pulmonary artery pressures were not statistically significant between patient subsets. Preprocedural right ventricular/left ventricular ratio (RV/LV) also did not differ significantly (1.74 vs. 1.75, P = 0.961). Thirty-day mortality was comparable (2 vs. 1, P = 0.332). Conclusion Next-day pulmonary angiography is a useful method to identify patients needing additional therapy including extended CDT and/or mechanical or suction thrombectomy in acute PE management. Pulmonary arterial pressures and preprocedural RV/LV ratios were not found to be predicative of those requiring further intervention.

/pdf/value-of-follow-up-angiography-additional-interventions-in-4crlx07r9v.pdf

Value of follow-up angiography: additional interventions in patients undergoing catheter-directed thrombolysis for massive and submassive pulmonary embolism.

Microwave ablation (MWA) is becoming the standard of care in treating liver lesions smaller than 3 cm benefiting from a plethora of radiofrequency ablation (RFA) data in the literature. Some of the advantages of MWA compared to RFA are as follows: Faster ablations, more reproducible and predictable heating, better thermal conductivity in different liver tissue environments, and less susceptibility to heat-sink effect. Despite its many advantages, there are still concerns regarding MWA use in high-risk locations such as near portal veins, near the bile ducts, and near the heart. Some centers have historically considered these tumor locations as a contraindication to percutaneous thermal ablation. In this review, we summarize the current data on the safety of MWA of liver tumors in challenging locations. We also discuss several technical tips with examples provided.

Merve Ozen

Papers

Acute Headache in the Emergency Setting.

Hemodialysis Catheters: Update on Types, Outcomes, Designs and Complications.

Re: Liver tumor ablation in difficult locations: Microwave ablation of perivascular and subdiaphragmatic hepatocellular carcinoma.

Value of follow-up angiography: additional interventions in patients undergoing catheter-directed thrombolysis for massive and submassive pulmonary embolism.

Current perspectives on microwave ablation of liver lesions in difficult locations