Intracranial calcifications are frequently encountered in non-contrast computed tomography scan in both adult and pediatric age groups. They refer to calcifications within the brain parenchyma or vasculature and can be classified into several major categories: physiologic/age-related, dystrophic, congenital disorders/phakomatoses, infectious, vascular, neoplastic, metabolic/endocrine, inflammatory and toxic diseases. In this updated review, we present a wide spectrum of intracranial calcifications from both pediatric and adult populations focusing on their pattern, size and location.

The decision to perform WBCT scans in trauma should be at the discretion of the treating clinician. Applying a prediction rule would increase the number of WBCT scans performed without improving overall accuracy.

BackgroundLinear accelerator–based stereotactic radiosurgery delivered to cardiac arrhythmogenic foci could be a promising catheter‐free ablation modality. We tested the feasibility of in vivo atrioventricular (AV) node ablation in swine using stereotactic radiosurgery.Methods and ResultsFive Large White breed swine (weight 40–75 kg; 4 females) were studied. Single‐chamber St Jude pacemakers were implanted in each pig. The pigs were placed under general anesthesia, and coronary/cardiac computed tomography simulation scans were performed to localize the AV node. Cone beam computed tomography was used for target positioning. Stereotactic radiosurgery doses ranging from 35 to 40 Gy were delivered by a linear accelerator to the AV node, and the pigs were followed up with weekly pacemaker interrogations to observe for potential electrocardiographic changes. Once changes were observed, the pigs were euthanized, and pathology specimens of various tissues, including the AV node and tissues surrounding the AV node, were taken to study the effects of radiation. All 5 pigs had disturbances of AV conduction with progressive transition into complete heart block. Macroscopic inspection did not reveal damage to the myocardium, and pigs had preserved systolic function on echocardiography. Immunostaining revealed fibrosis in the target region of the AV node, whereas no fibrosis was detected in the nontargeted regions.ConclusionsCatheter‐free radioablation using linear accelerator–based stereotactic radiosurgery is feasible in an intact swine model.

Malignant struma ovarii is a rare disease; only a few cases are well documented in the literature. Thus, the overall prognosis and modalities of treatment are still somewhat controversial. In this article, the authors report a case of malignant struma ovarii discovered 4 years after ovariectomy after metastasis to the lungs and bones. Review of the pathology of the ovarian struma did not reveal the classic criteria of malignancy, there were, however, many features considered to be atypical and thus suspicious. The patient was treated by total thyroidectomy followed by repetitive doses of 131I. However, because of difficulties in increasing the level of endogenous thyrotropin (TSH) because of functional thyroid metastases in such an advanced disease, recombinant human thyrotropin (rhTSH; Thyrogen, thyrotropin alpha, Genzyme Corporation, Cambridge, MA) was used before administration of radioiodine. With this therapeutic protocol, the patient is still clinically stable 2 years after diagnosis.

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P ersonalized medicine is a popular topic in radiology today. Scientists are flooding academic journals, conference proceedings, and book chapters with arguments about radiation reduction strategies with a personalized approach. However, contrast media (CM) dose reduction has been overlooked, which is of great concern. As such, 3% of all patients admitted for renal dialysis are a direct result of excessive CM volume delivered during radiologic imaging in the course of their hospital stay (1).Studies suggest that CM volumes employed during renal computed tomography (CT) angiography (CTA) range from 30-120 mL (2-4). This wide array of CM dose has different effects on scanner parameters. For example, employing 30 mL CM volume with a tube current selection of 80 kVp renders acceptable image quality. However, image quality can either be quantitative or qualitative in nature, which increase the subjectivity of good versus acceptable image quality with desired CM doses. Therefore, judging optimal image quality is determined by the amount of noise and vascular opacification of the renal arteries.Vascular opacification that is too low may compromise the visualization of small renal vasculature and underestimate plaque formation and stenosis (5). Previous studies on contrast-injection protocols for renal CTA suggested that the adequate attenuation value for the arteries is greater than 211 Hounsfield units (HU) (6). However, attenuation values of the renal arteries have reached as high as 435±48 HU, while those of the renal veins have reached 277±29 HU (7).The sensitivity and specificity for diagnosing greater than 50% renal artery stenosis during renal CTA range from 67%-100% and 77%-98%, respectively (8). Renal magnetic resonance angiography (MRA) has sensitivity and specificity of 88%-100% and 70%-100% with low interobserver variability, especially for severe stenosis greater than 70% (9).Renal CTA provides accurate, noninvasive, and time-efficient diagnostic evaluation for medical management of renal arterial disease as well as creating a roadmap prior to surgical intervention. Such clinical questions arise when a hypertensive individual has renal CTA to exclude renal artery stenosis, fibromuscular dysplasia, or dissection. Pathology-specific renal CTA examinations include determining if vasculitis involves the renal arteries or the extent of renal aneurysmal changes. Preoperative renal CTA planning can be useful for nephron-sparing surgery prior to resection of renal masses or as post-procedural follow-up of renal stenting or surgical revascularization. Finally, renal CTA is also employed in the evaluation of the kidney donor and recipient prior to transplantation. ABSTRACTOver the last decade, exponential advances in computed tomography (CT) technology have resulted in improved spatial and temporal resolution. Faster image acquisition enabled renal CT angiography to become a viable and effective noninvasive alternative in diagnosing renal vascular pathologies. However, with these advances, new challenges in contras...

• Optimal opacification of the pulmonary arteries is essential for CT pulmonary angiography. • Matching timing with vessel dynamics significantly improves vessel opacification. • This leads to increased arterial opacification and reduced venous opacification. • This can also lead to a reduced volume of contrast agent.

The pathogenesis of multiple sclerosis is characterized by a cascade of pathobiologic events, ranging from focal lymphocytic infiltration and microglia activation to demyelination and axonal degeneration. MS has several of the hallmarks of an inflammatory autoimmune disorder, including breakdown of the BBB. Gadolinium-enhanced MR imaging is currently the reference standard to detect active inflammatory lesions in MS. Knowledge of the patterns and mechanisms of contrast enhancement is vital to limit the radiologic differential diagnosis in the staging and evaluation of MS lesion activity. The aim of this review was the following: 1) to outline the pathophysiology of the effect of lymphocyte-driven inflammation in MS, 2) to describe the effects of gadolinium on the BBB and glymphatic system, and 3) to describe gadolinium enhancement patterns and artifacts that can mimic lesions in MS.ABBREVIATIONS: Gd 3ϩ ϭ gadolinium; MTR ϭ magnetization transfer ratio