Spontaneous regression of an idiopathic arteriovenous fistula of the right vertebral artery.

A previously healthy 53-year-old male presented with a 2-month history of pulsatile tinnitus, worsening headaches, and neck pain. Given the clinical symptoms, a workup was initiated to assess for a vascular etiology such as a dural arteriovenous fistula.

'Do not touch' lesions of the skull base.

Imaging of the skull base presents many challenges due to its anatomical complexity, numerous normal variants and lack of familiarity to many radiologists. As the skull base is a region which is not amenable to physical examination and as lesions of the skull base are generally difficult to biopsy and even more difficult to operate on, the radiologist plays a major role in directing patient management via accurate image interpretation. Knowledge of the skull base should not be limited to neuroradiologists and head and neck radiologists, however, as the central skull base is routinely included in the field of view when imaging the brain, cervical spine, or head and neck with computed tomography or magnetic resonance imaging, and hence, its nuances should be familiar to general radiologists as well. We herein review the imaging findings of a subcategory of lesions of the central skull base, the 'do not touch' lesions.

Medical student radiology externs: increasing exposure to radiology, improving education, and influencing career choices.

PURPOSE: The radiology externship program at the authors' institution introduces medical students to radiology using a hands-on approach and is tailored to interested third-year medical students. There are currently limited data available on whether the program increases exposure to radiology in a positive fashion and how it influences medical students' education and career choices. METHODS: In September 2010, current and former externs between 2007 and 2010 were surveyed using an anonymous, Web-based survey. RESULTS: The response rates were 100% (11 of 11) for current externs and 52% (15 of 29) for former externs, for an overall response rate of 65% (26 of 40). The respondents included 20 men and 5 women. The average age of respondents was 27.3 ± 2.5 years. Forty-six percent of former externs (6 of 13) had matched to radiology residencies, whereas the remainder had matched to various surgical and nonsurgical subspecialties. Eighty-four percent (21 of 25) had overall positive ratings of the program. Ninety-two percent (23 of 25) felt they had a better understanding of which test was most appropriate to order for common indications, and 88% (22 of 25) felt that they had a better understanding of imaging contraindications. Sixty-eight percent (17 of 25) felt that they had a better understanding of risk-benefit analysis involving imaging using ionizing radiation, and 56% (14 of 25) felt more confident in discussing these matters with their patients. CONCLUSIONS: This radiology externship program increases exposure to radiology in a positive fashion, increases understanding of the appropriate use of imaging modalities and their associated clinical benefits and risks, and influences medical students' career choices. These results add to the evidence that this type of program is mutually beneficial to medical students, residents, and clinical colleagues and suggest that more medical schools and radiology departments should evaluate the feasibility of starting radiology externship programs.

Spontaneously ruptured intraspinal epidermoid cyst causing chemical meningitis.

We report a 53-year-old woman with a rare ruptured lumbar intraspinal epidermoid cyst causing chemical meningitis evaluated with MRI (including diffusion-weighted imaging), with histopathologic correlation.

Previous statin use is not associated with an increased prevalence or degree of gradient-echo lesions in patients with acute ischemic stroke or transient ischemic attack.

BACKGROUND AND PURPOSE: Microhemorrhages on gradient-echo T2*-weighted MRI sequences are often found in patients with cerebrovascular disease and are related to intracerebral hemorrhage. Because statin therapy is associated with increased risk of intracerebral hemorrhage, we investigated whether statin use was also associated with microhemorrhages in patients with acute ischemic stroke or transient ischemic attack. METHODS: We performed a retrospective analysis on prospectively collected data from a stroke registry containing patients with acute ischemic stroke or transient ischemic attack. The primary and secondary outcome variables were the prevalence and degree of microhemorrhages as detected on gradient-echo MRI sequences and categorized as mild (1-2), moderate (3-10), or severe (>10). The location of the microhemorrhages was noted and rated by 2 neuroradiologists. Previous use of statins and other covariates were assessed as potential predictors. RESULTS: Three hundred forty-nine patients were admitted from June 2008 to July 2009, and 300 of which were analyzed. Microhemorrhages were detected in 70 subjects (23%); 35 had only lobar lesions, 16 had only deep lesions, and 19 had both lobar and deep lesions. On univariate and multivariate analysis, statin therapy was not associated with the prevalence (OR, 0.73; 95% CI, 0.36-1.51; P=0.40) or degree of microhemorrhages modeled for lesser severity (OR, 2.31; 95% CI, 0.61-8.75; P=0.22). CONCLUSIONS: Previous statin therapy was not associated with the prevalence or degree of microhemorrhages in patients with acute ischemic stroke or transient ischemic attack. The association between statins and intracerebral hemorrhage does not appear to be mediated through microhemorrhages.

Determination of blood longitudinal relaxation time (T1) at high magnetic field strengths.

In this study, a circulation system was used to measure T(1) values of bovine blood under physiological conditions at field strengths of 4.7, 7 and 9.4 T. Results show that T(1) increases linearly with magnetic field B(0) and can be described with the equation T(1)=129 ms/T B(0)+1167 ms for magnetic field strengths between 1.5 and 9.4 T.