Imaging of Small Renal Masses before and after Thermal Ablation.

Thermal ablation of small renal masses is increasingly accepted as an alternative to partial nephrectomy, particularly in patients with multiple comorbidities. Many professional societies support this alternate treatment with updated guidelines. Before performing thermal ablation, it is important to stratify risk and assess technical feasibility by evaluating tumor imaging features such as size, location, and centrality. Routine postablation imaging with CT or MRI is necessary for assessment of residual or recurrent tumor, evidence of complications, or new renal masses outside the ablation zone. The normal spectrum and evolution of findings at CT and MRI include a halo appearance of the ablation zone, ablation zone contraction, and ablation zone calcifications. Tumor recurrence frequently manifests at CT or MRI as new nodular enhancement at the periphery of an expanding ablation zone, although it is normal for the ablation zone to enlarge within the first few months. Recognizing early tumor recurrence is important, as small renal masses are often easily treated with repeat ablations. Potential complications of thermal ablation include vascular injury, urine leak, ureteral stricture, nerve injury, and bowel perforation. The risk of these complications may be related to tumor size and location.©RSNA, 2019.

Coronary Atherosclerotic Plaque Regression: JACC State-of-the-Art Review.

Over the last 3 decades there have been substantial improvements in treatments aimed at reducing cardiovascular (CV) events. As these treatments have been developed, there have been parallel improvements in coronary imaging modalities that can assess plaque volumes and composition, using both invasive and noninvasive techniques. Plaque progression can be seen to precede CV events, and therefore, many studies have longitudinally assessed changes in plaque characteristics in response to various treatments, aiming to demonstrate plaque regression and improvements in high-risk features, with the rationale being that this will reduce CV events. In the past, decisions surrounding treatments for atherosclerosis have been informed by population-based risk scores for initiation in primary prevention and low-density lipoprotein cholesterol levels for titration in secondary prevention. If outcome data linking plaque regression to reduced CV events emerge, it may become possible to directly image plaque treatment response to guide management decisions.

MRI safety considerations during pregnancy.

The use of magnetic resonance imaging (MRI) during pregnancy is on the rise due its ability to provide detailed cross-sectional anatomy without ionizing radiation. Despite the favorable radiation profile, theoretically concerns regarding the safety of MRI and gadolinium-based contrast agent (GBCA) administration have been raised. Currently there are no studies that have shown any attributable harms of MRI during any trimester of pregnancy although prospective and longitudinal studies are lacking. GBCA administration may be associated with a slightly higher rate of neonatal death, although this is based on a single, large cohort study. Understanding the available evidence regarding MRI safety during pregnancy in the context of current society guidelines will help the radiologist serve as a valuable resource to patients and referring providers.

Sex differences in the long-term neuropsychological outcome of mild traumatic brain injury.

PRIMARY OBJECTIVE: To investigate possible sex differences in neuropsychological functioning among patients following mild traumatic brain injury (TBI). METHODS AND PROCEDURES: Retrospective records analysis of the neuropsychological test results of 102 participants with head injury, including 62 males and 40 females. MAIN OUTCOME AND RESULTS: A multivariate analysis of variance indicated that females and males performed similarly on neuropsychological tests, on average, approximately 2 years after minor head trauma. A sex-by-age interaction effect was found on the Category and Trail Making A Tests, with a pattern similar to those obtained in a previous research. CONCLUSIONS: Although past research has found that females develop more TBI-related neuropsychological deficits than males in the immediate post-injury period, the present study found that, overall, sex differences in the performance of patients with mild TBI on a variety of neuropsychological tests were insignificant. More investigation into the sex-by-age interaction effect appears warranted.

Can pre-hospital administration reduce time to initial antibiotic therapy in septic patients?

OBJECTIVE: To quantify the potential time saved with pre-hospital antibiotic therapy in sepsis. METHODS: Study data for adult patients transported by Ambulance Victoria (AV), and enrolled into the Australasian Resuscitation In Sepsis Evaluation (ARISE), were linked with pre-hospital electronic records. RESULTS: An AV record was identified for 240 of 341 ARISE patients. The pre-hospital case notes referred to potential infection in 165 patients. The median time to first antibiotic administration from loading the patient into the ambulance was 107 (74-160) min. CONCLUSIONS: ARISE patients in Victoria were frequently identified pre-hospital. An opportunity exists to study the feasibility of pre-hospital antibiotic therapy.

MRI Features Associated with TERT Promoter Mutation Status in Glioblastoma.

BACKGROUND AND PURPOSE: Telomerase reverse transcriptase (TERT) promoter mutations are associated with worse prognosis in glioblastoma. The purpose of this study was to evaluate whether TERT mutation status was associated with specific morphologic and quantitative imaging features. METHODS: Twenty-nine patients with isocitrate dehydrogenase 1/2-wildtype glioblastoma (13 TERT-wildtype, 16 TERT-mutated), who underwent preoperative magnetic resonance (MR) imaging were included in this retrospective study. Qualitative imaging phenotypes were evaluated using the Visually Accessible Rembrandt Images (VASARIs) feature set. Histogram analysis of apparent diffusion coefficient (ADC) and dynamic contrast-enhanced MR perfusion values were performed on enhancing tumor volumes-of-interest, and differences between TERT-wildtype and TERT-mutated tumors were assessed. RESULTS: VASARI analysis demonstrated that the majority of morphologic features were not significantly different between TERT-wildtype and TERT-mutated tumors, although a higher proportion of TERT-wildtype tumors featured nonenhancing tumor crossing midline (P = .014). TERT-mutated tumors demonstrated lower median rate constant kep (.38 vs. .76, P = .03) and lower median volume transfer coefficient Ktrans (.13 vs. .31, P = .02). There was no significant difference in median plasma volume vp (P = .92) or ADC values (P = .66) between the two groups. We further found a significant interaction between median kep and Ktrans and TERT status, respectively, suggesting greater risk of death with increasing blood-brain barrier dysfunction in TERT-mutated but not in TERT-wildtype tumors. CONCLUSION: Our study demonstrates evidence of altered permeability metrics associated with TERT mutation in glioblastoma, laying the foundation for future prospective studies assessing implications for therapeutic management and clinical outcomes.

Intra-Arterial MR Perfusion Imaging of Meningiomas: Comparison to Digital Subtraction Angiography and Intravenous MR Perfusion Imaging.

BACKGROUND AND PURPOSE: To evaluate the ability of IA MR perfusion to characterize meningioma blood supply. METHODS: Studies were performed in a suite comprised of an x-ray angiography unit and 1.5T MR scanner that permitted intraprocedural patient movement between the imaging modalities. Patients underwent intra-arterial (IA) and intravenous (IV) T2* dynamic susceptibility MR perfusion immediately prior to meningioma embolization. Regional tumor arterial supply was characterized by digital subtraction angiography and classified as external carotid artery (ECA) dural, internal carotid artery (ICA) dural, or pial. MR perfusion data regions of interest (ROIs) were analyzed in regions with different vascular supply to extract peak height, full-width at half-maximum (FWHM), relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), and mean transit time (MTT). Linear mixed modeling was used to identify perfusion curve parameter differences for each ROI for IA and IV MR imaging techniques. IA vs. IV perfusion parameters were also directly compared for each ROI using linear mixed modeling. RESULTS: 18 ROIs were analyzed in 12 patients. Arterial supply was identified as ECA dural (n = 11), ICA dural (n = 4), or pial (n = 3). FWHM, rCBV, and rCBF showed statistically significant differences between ROIs for IA MR perfusion. Peak Height and FWHM showed statistically significant differences between ROIs for IV MR perfusion. RCBV and MTT were significantly lower for IA perfusion in the Dural ECA compared to IV perfusion. Relative CBF in IA MR was found to be significantly higher in the Dural ICA region and MTT significantly lower compared to IV perfusion.