Color Fusion of Magnetic Resonance Images Improves Intracranial Volume Measurement in Studies of Aging

Background: Comparison of intracranial volume (ICV) measurements in different subpopulations offers insight into age-related atrophic change and pathological loss of neuronal tissue. For such comparisons to be meaningful the accuracy of ICV measurement is paramount. Color magnetic resonance images (MRI) have been utilised in several research applications and are reported to show promise in the clinical arena. Methods: We selected a sample of 150 older community-dwelling individuals (age 71 to 72 years) representing a wide range of ICV, white matter lesions and atrophy. We compared the extraction of ICV by thresholding on T2*-weighted MR images followed by manual editing (reference standard) done by an analyst trained in brain anatomy, with thresholding plus computational morphological operations followed by manual editing on a framework of a color fusion technique (MCMxxxVI) and two automatic brain segmentation methods widely used, these last three done by two image analysts. Results: The range of ICV was 1074 to 1921 cm3 for the reference standard. The mean difference between the reference standard and the ICV measured using the technique that involved the color fusion was 2.7%, while it was 5.4% compared with any fully automatic technique. However, the 95% confidence interval of the difference between the reference standard and each method was similar: it was 7% for the segmentation aided by the color fusion and was 7% and 8.3% for the two fully automatic methods tested. Conclusion: For studies of aging, the use of color fusion MRI in ICV segmentation in a semi-automatic framework delivered best results compared with a reference standard manual method. Fully automated methods, while fast, all require manual editing to avoid significant errors and, in this post-processing step color fusion MRI is recommended.

Clinical management of cerebral small vessel disease:a call for a holistic approach

Cerebral small vessel disease(SVD)is a common global brain disease that causes cognitive impairment,ischemic or hemorrhagic stroke,problems with mobility,and neuropsychiatric symptoms.The brain damage,seen as focal white and deep grey matter lesions on brain magnetic resonance imaging(MRI)or computed tomography(CT),typically accumulates"covertly"and may reach an advanced state before being detected incidentally on brain scanning or causing symptoms.Patients have typically presented to different clinical services or been recruited into research focused on one clinical manifestation,perhaps explaining a lack of awareness,until recently,of the full range and complexity of SVD.In this review,we discuss the varied clinical presentations,established and emerging risk factors,relationship to SVD features on MRI or CT,and the current state of knowledge on the effectiveness of a wide range of pharmacological and lifestyle interventions.The core message is that effective assessment and clinical management of patients with SVD,as well as future advances in diagnosis,care,and treatment,will require a more"joined-up"’approach.This approach should integrate clinical expertise in stroke neurology,cognitive,and physical dysfunctions.It requires more clinical trials in order to improve pharmacological interventions,lifestyle and dietary modifications.A deeper understanding of the pathophysiology of SVD is required to steer the identification of novel interventions.An essential prerequisite to accelerating clinical trials is to improve the consistency,and standardization of clinical,cognitive and neuroimaging endpoints.