Application of mask images of contrast-enhanced MR angiography to detect carotid intraplaque hemorrhage in patients with moderate to severe symptomatic and asymptomatic carotid stenosis.

PURPOSE: Carotid intraplaque hemorrhage (IPH) on MRI predicts stroke. Magnetization-prepared rapid acquisition gradient (MP-RAGE) is widely used to detect IPH. CE-MRA is used routinely to assess stenosis. Initial studies indicated that IPH can be identified on mask images of CE-MRA, while Time-of-Flight (TOF) images were reported to have high specificity but lower sensitivity. We investigated the diagnostic accuracy of detecting IPH on mask images of CE-MRA and TOF. METHODS: Thirty-six patients with ≥ 50% stenosis enrolled in the ongoing 2nd European Carotid Surgery Trial underwent carotid MRI. A 5-point quality score was used. Inter-observer agreement between two independent readers was determined. The sensitivity and specificity of IPH detection on mask MRA and TOF were calculated with MP-RAGE as a reference standard. RESULTS: Of the 36 patients included in the current analysis, 66/72 carotid arteries could be scored. The inter-observer agreements for identifying IPH on MP-RAGE, mask, and TOF were outstanding (κ: 0.93, 0.96, and 0.85). The image quality of mask (1.42 ± 0.66) and TOF (2.42 ± 0.66) was significantly lower than MP-RAGE (3.47 ± 0.61). When T1w images were used to delineate the outer carotid wall, very high specificities (>95%) of IPH detection on mask and TOF images were found, while the sensitivity was high for mask images (>81%) and poor for TOF (50-60%). Without these images, the specificity was still high (>97%), while the sensitivity reduced to 62-71%. CONCLUSION: Despite the lower image quality, routinely acquired mask images from CE-MRA, but not TOF, can be used as an alternative to MP-RAGE images to visualize IPH.

Cerebral microbleeds: a guide to detection and clinical relevance in different disease settings.

Cerebral microbleeds have emerged as an important new imaging marker of cerebral small vessel disease. With the development of MRI techniques that are exquisitely sensitive to paramagnetic blood products, such as T2*-weighted gradient-recalled echo and susceptibility-weighted sequences, microbleeds have been detected in ever-increasing numbers of patients in stroke and cognitive clinics, as well as in healthy older people and in a variety of other rarer diseases and syndromes. Detection of cerebral microbleeds has clinical implications with respect to the diagnosis of the underlying small vessel disease, the safety of antithrombotic use, and the risk of symptomatic intracerebral haemorrhage, cognitive impairment and dementia. This article provides a guide to the detection and clinical relevance of cerebral microbleeds in different conditions based on a comprehensive review of the literature and own findings in research and clinical practice.