Incidental vascular findings on brain magnetic resonance angiography.

Given the ever-increasing utilization of magnetic resonance angiography, incidental vascular findings are increasingly discovered on exams performed for unconnected indications. Some incidental lesions represent pathology and require further intervention and surveillance, such as aneurysm, certain vascular malformations, and arterial stenoses or occlusions. Others are benign or represent normal anatomic variation, and may warrant description, but not further work-up. This review describes the most commonly encountered incidental findings on magnetic resonance angiography, their prevalence, clinical implications, and any available management recommendations.

Advanced cross-sectional imaging of cerebral aneurysms.

While the rupture rate of cerebral aneurysms is only 1% per year, ruptured aneurysms are associated with significant morbidity and mortality, while aneurysm treatments have their own associated risk of morbidity and mortality. Conventional markers for aneurysm rupture include patient-specific and aneurysm-specific characteristics, with the development of scoring systems to better assess rupture risk. These scores, however, rely heavily on aneurysm size, and their accuracy in assessing risk in smaller aneurysms is limited. While the individual risk of rupture of small aneurysms is low, due to their sheer number, the largest proportion of ruptured aneurysms are small aneurysms. Conventional imaging techniques are valuable in characterizing aneurysm morphology; however, advanced imaging techniques assessing the presence of inflammatory changes within the aneurysm wall, hemodynamic characteristics of blood flow within aneurysm sacs, and imaging visualization of irregular aneurysm wall motion have been used to further determine aneurysm instability that otherwise cannot be characterized by conventional imaging techniques. The current manuscript reviews conventional imaging techniques and their value and limitations in cerebral aneurysm characterization, and evaluates the applications, value and limitations of advanced aneurysm imaging and post-processing techniques including intracranial vessel wall MRA, 4D-flow, 4D-CTA, and computational fluid dynamic simulations.

Idiopathic intracranial hypertension imaging approaches and the implications in patient management.

Idiopathic intracranial hypertension (IIH) represents a clinical disease entity without a clear etiology, that if left untreated, can result in severe outcomes, including permanent vision loss. For this reason, early diagnosis and treatment is necessary. Historically, the role of cross-sectional imaging has been to rule out secondary or emergent causes of increased intracranial pressure, including tumor, infection, hydrocephalus, or venous thrombosis. MRI and MRV, however, can serve as valuable imaging tools to not only rule out causes for secondary intracranial hypertension but can also detect indirect signs of IIH resultant from increased intracranial pressure, and demonstrate potentially treatable sinus venous stenosis. Digital subtraction venographic imaging also plays a central role in both diagnosis and treatment, providing enhanced anatomic delineation and temporal flow evaluation, quantitative assessment of the pressure gradient across a venous stenosis, treatment guidance, and immediate opportunity for endovascular therapy. In this review, we discuss the multiple modalities for imaging IIH, their limitations, and their contributions to the management of IIH.

Measuring stiffness of normal medial collateral ligament in healthy volunteers via shear wave elastography.

PURPOSE: We aim to determine a reference data set for normal medial collateral ligament (MCL) stiffness values using shear wave elastography (SWE). METHODS: Quantitative stiffness of the MCL was measured at three levels: the proximal (MCL area from the level of the medial meniscus to the level of the femoral attachment), the middle (MCL area at the level of the medial meniscus), and the distal (MCL area from the level of the medial meniscus to the level of the tibial attachment) segments of the MCL at a knee position of 0°. RESULTS: A total of 60 MCL of 30 healthy volunteers (15 female, 15 male) were examined. The mean stiffness values of the proximal, middle, and distal MCL for observer 1 were 32.25 ± 6.44, 34.25 ± 6.84, and 35.47 ± 6.98, respectively. The mean stiffness values of the proximal, middle, and distal MCL for observer 2 were 33.56 ± 6.76, 35.44 ± 6.91, and 36.32 ± 7.04, respectively. CONCLUSION: SWE has a strong potential to be a method of choice for evaluating MCL stiffness. Our study participants were healthy volunteers and the data can be used as reference data for future studies.

Diagnostic performance of 2D shear wave elastography in predicting liver fibrosis in patients with chronic hepatitis B and C: a histopathological correlation study.

PURPOSE: In this study, we investigated the diagnostic efficacy of 2D-Shear Wave Elastography (2D-SWE) in detecting stages of liver fibrosis and determining the disease-specific cut-off values in patients with chronic hepatitis B and C infection, using histopathological analysis as the reference method. METHOD: Our study included 103 consecutive adult patients with chronic hepatitis B and C infection (CHB and CHC) who had liver biopsy within three months of elastography examination. A real-time 2D-SWE was performed using the LOGIQ E9 system (GE Medical Systems, Wisconsin, USA). The correlation between the liver stiffness measurements and the METAVIR scores was evaluated. The diagnostic performance of 2D-SWE was assessed, and cut-off values were set. RESULTS: We found a statistically significant positive correlation between elastography values and the degree of liver fibrosis (Spearman's correlation coefficient = 0.76 and 0.83 for CHB and CHC; respectively) (p = 0.0001). The stiffness cut-off values were F ≥ 1: 5.92 kPa, F ≥ 2: 7.69 kPa, F ≥ 3: 8.97 kPa, F ≥ 4: 12.15 kPa in CHB; and F ≥ 1: 6.09 kPa, F ≥ 2: 7.81 kPa, F ≥ 3: 9.0 kPa, F ≥ 4: 12.47 kPa in CHC patients. CONCLUSION: 2D-SWE is reliable and accurate for the diagnosis of liver fibrosis. In selected patients, 2D-SWE may be useful in reducing the need for liver biopsy when staging fibrosis. Further studies in larger prospective series are needed to confirm these results and determine the most appropriate cut-off values for each stage of liver fibrosis.

Glycemia and cognitive function in metabolic syndrome and coronary heart disease.

OBJECTIVE: Higher hemoglobin A1c (HbA1c) is associated with lower cognitive function in type 2 diabetes. To determine whether associations persist at lower levels of dysglycemia in patients who have established cardiovascular disease, cognitive performance was assessed in the Targeting INflammation Using SALsalate in CardioVascular Disease (TINSAL-CVD) trial. METHODS: The age-adjusted relationships between HbA1c and cognitive performance measured by the Mini-Mental State Examination, Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, Trail Making Test, and Categorical Verbal Fluency were assessed in 226 men with metabolic syndrome and established stable coronary artery disease. RESULTS: Of the participants, 61.5% had normoglycemia, 20.8% had impaired fasting glucose, and 17.7% had type 2 diabetes. HbA1c was associated with cognitive function tests of Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, Trail Making Test, and Categorical Verbal Fluency (all P < .02), but not the Mini-Mental State Examination. In an age-adjusted model, a 1% (11 mmol/mol) higher HbA1c value was associated with a 5.9 lower Digit Symbol Substitution Test score (95% confidence interval [CI], -9.58 to -2.21; P < .0001); a 2.44 lower Rey Auditory Verbal Learning Test score (95% CI, -4.00 to -0.87; P < .0001); a 15.6 higher Trail Making Test score (95% CI, 5.73 to 25.6; P < .0001); and a 3.71 lower Categorical Verbal Fluency score (95% CI, -6.41 to -1.01; P < .02). In a multivariate model adjusting for age, education, and cardiovascular covariates, HbA1c remained associated with cognitive function tests of Rey Auditory Verbal Learning Test (R(2) = 0.27, P < .0001), Trail Making Test (R(2) = 0.18, P < .0001), and Categorical Verbal Fluency (R(2) = 0.20, P < .0001), although association with the Digit Symbol Substitution Test was reduced. CONCLUSIONS: Higher HbA1c is associated with lower cognitive function performance scores across multiple domain tests in men with metabolic syndrome and coronary artery disease. Future studies may demonstrate whether glucose lowering within the normative range improves cognitive health.