Spatial relation between microbleeds and amyloid deposits in amyloid angiopathy

Advanced cerebrovascular β‐amyloid deposition (cerebral amyloid angiopathy, CAA) is associated with cerebral microbleeds, but the precise relationship between CAA burden and microbleeds is undefined. We used T2*‐weighted magnetic resonance imaging (MRI) and noninvasive amyloid imaging with Pittsburgh Compound B (PiB) to analyze the spatial relationship between CAA and microbleeds. On coregistered positron emission tomography (PET) and MRI images, PiB retention was increased at microbleed sites compared to simulated control lesions (p = 0.002) and declined with increasing distance from the microbleed (p < 0.0001). These findings indicate that microbleeds occur preferentially in local regions of concentrated amyloid and support therapeutic strategies aimed at reducing vascular amyloid deposition. Ann Neurol 2010     

Diagnostic performance of MDCT, PET/CT and gadoxetic acid (Primovist?)-enhanced MRI in patients with colorectal liver metastases being considered for hepatic resection: initial experience in a single centre

Purpose

To compare the relative diagnostic performance of MDCT, PET/CT and Primovist-enhanced MRI (P-MRI) in the pre-resection work-up of colorectal cancer (CRC) liver metastases.

Method and materials

This was a retrospective study of consecutive referrals for CRC liver metastases. All patients had MDCT, PET/CT and P-MRI examinations within 3?months of each other. They were divided into 2 groups: resected and unresected. Patients in the resected group underwent liver resection within 3?months of the imaging studies. In the unresected group, patients were unresectable by imaging criteria or are awaiting surgery. Standard of reference (SOR) was intra-operative ultrasound findings and pathology for the resected group. Intermodality comparison was the SOR for the unresected group. Number of lesions identified by each imaging modality for each patient was recorded. Sensitivity (95% CI) and PPV were calculated for each imaging modality in the resected group.

Results

There were 19 patients in the resected group and 11 patients in the unresected group. The sensitivity (96%) and PPV (0.91) of P-MRI were both superior to that of MDCT (P?=?0.0009) and PET/CT (P?=?0.0003). Intermodality comparison showed that P-MRI detected more lesions than MDCT and PET/CT.

Conclusion

The sensitivity and PPV of P-MRI was superior to that of MDCT and PET/CT. P-MRI probably has the most added value if used after MDCT and PET/CT in patients still considered eligible for liver resection.     

Cerebrospinal fluid amyloid β40 is decreased in cerebral amyloid angiopathy

Cerebral amyloid angiopathy is caused by deposition of the amyloid β protein in the cerebral vasculature. In analogy to previous observations in Alzheimer disease, we hypothesized that analysis of amyloid β₄₀ and β₄₂ proteins in the cerebrospinal fluid might serve as a molecular biomarker. We observed strongly decreased cerebrospinal fluid amyloid β₄₀ (p < 0.01 vs controls or Alzheimer disease) and amyloid β₄₂ concentrations (p < 0.001 vs controls and p < 0.05 vs Alzheimer disease) in cerebral amyloid angiopathy patients. The combination of amyloid β₄₂ and total tau discriminated cerebral amyloid angiopathy from controls, with an area under the receiver operator curve of 0.98. Our data are consistent with neuropathological evidence that amyloid β₄₀ as well as amyloid β₄₂ protein are selectively trapped in the cerebral vasculature from interstitial fluid drainage pathways that otherwise transport amyloid β proteins toward the cerebrospinal fluid. Ann Neurol 2009;66:245–249     

Relative power of clinical, exercise test, and angiographic variables in predicting clinical outcome after myocardial infarction: the Newham and Tower Hamlets study.

The interrelations of clinical, exercise test, and angiographic variables and their relative values in predicting specific clinical outcomes after myocardial infarction have not been fully established. Of 302 consecutive stable survivors of infarction, 262 performed a predischarge submaximal exercise test. In the first year after infarction patients with a "positive" exercise test were 13 times more likely to die, 2.8 times more likely to have an ischaemic event, and 2.3 times more likely to develop left ventricular failure than patients with negative tests. Patients with positive exercise tests underwent cardiac catheterization. Features of the history, 12 lead electrocardiogram, in-hospital clinical course, exercise test, and left ventricular and coronary angiograms that predicted these clinical end points were identified by univariate analysis. Then multivariable analysis was used to assess the relative powers of all variables in predicting end points. Certain features of the exercise test remained independent predictors of future ischaemic events and the development of overt left ventricular failure, but clinical and angiographic variables were more powerful predictors of mortality. Because the exercise test is also used to select patients for angiography, however, the results of this study strongly support the use of early submaximal exercise testing after infarction.     

Radiofrequency-assisted balloon dilatation in patients with pulmonary valve atresia and an intact ventricular septum.

OBJECTIVE--To investigate the efficacy and safety of transcatheter radiofrequency-assisted valve dilatation for infants with pulmonary valve atresia and intact ventricular septum as an alternative to the use of laser heated wires. DESIGN--Prospective clinical study. SETTING--Three paediatric cardiology centres. PATIENTS--Four children (aged 5-101 days, weight 2.8 kg) with pulmonary valve atresia and intact ventricular septum underwent percutaneous radiofrequency-assisted valve dilatation. METHODS--After delineating the atretic valve by angiography, 0.020 inch or 0.018 inch radiofrequency wires were used to perforate the atretic valve. The valve was then dilated with conventional balloon dilatation catheters up to the valve annulus diameter. RESULTS--In all four cases the radiofrequency wire perforated the atretic pulmonary valve and balloon dilatation was successful. In one patient the radiofrequency wire also passed through the anterior wall of the pulmonary artery causing tamponade which required surgical repair shortly afterwards. This patient died from sepsis six days later. One patient died three weeks after the procedure from septicaemia and a paradoxical coronary embolus. Two patients were discharged after 4 and 14 days respectively. CONCLUSIONS--Radiofrequency-assisted valve dilatation is a promising alternative to the recently developed laser wire technique. The major advantages are a reduction in cost and improved safety for the staff performing the procedure.