There is an extensive spectrum of autoimmune entities that can involve the central nervous system, which has expanded with the emergence of new imaging modalities and several clinicopathologic entities. Clinical presentation is usually non-specific, and imaging has a critical role in the workup of these diseases. Immune-mediated diseases of the brain are not common in daily practice for radiologists and, except for a few of them such as multiple sclerosis, there is a vague understanding about differentiating them from each other based on the radiological findings. In this review, we aim to provide a practical diagnostic approach based on the unique radiological findings for each disease. We hope our diagnostic approach will help radiologists expand their basic understanding of the discussed disease entities and narrow the differential diagnosis in specific clinical scenarios. An understanding of unique imaging features of these disorders, along with laboratory evaluation, may enable clinicians to decrease the need for tissue biopsy.

Autoimmune disease of the head and neck (H&N) could be primary or secondary to systemic diseases, medications, or malignancies. Immune-mediated diseases of the H&N are not common in daily practice of radiologists; the diagnosis is frequently delayed because of the non-specific initial presentation and lack of familiarity with some of the specific imaging and clinical features. In this review, we aim to provide a practical diagnostic approach based on the specific radiological findings for each disease. We hope that our review will help radiologists expand their understanding of the spectrum of the discussed disease entities, help them narrow the differential diagnosis, and avoid unnecessary tissue biopsy when appropriate based on the specific clinical scenarios.

Introduction: Stratifying patients with coronary artery disease (CAD) remains challenging. Assessing CAD using myocardial mass at-risk may help identify patients at higher risk of acute coronary syndrome. Hypothesis: This study investigated whether quantitative myocardial mass at-risk (MMAR) can improve prognostication of future culprit coronary lesions at the time of acute coronary syndrome (ACS) events. Methods: From the multicenter, international ICONIC study, 49 patients suspected of coronary artery disease (CAD) going coronary CT angiography imaging (CCTA) were followed to the occurrence of the first ACS. At the time of ACS, culprit lesion was adjudicated by invasive coronary angiography by a group of cardiologists blinded to the previously acquired CCTA. MMAR was calculated for each lesion using the minimum-cost path technique, a previously validated method for calculating myocardial perfusion territories. Left ventricle myocardial segmentation and coronary centerline extraction was performed and used to calculate MMAR distal to all identifiable culprit and non-culprit coronary lesions. Results: In the study sample, 243 coronary lesions were identified on CCTA (194 non-culprit lesions; 49 culprit lesions). The mean MMAR, as a percentage of total left ventricle myocardial mass, for all lesions was 24.6±12.4%. The mean MMAR was 23.1±12.5% and 30.3±10.3% for non-culprit and culprit lesions, respectively (p<0.05). Receiver operating characteristic curve analysis was performed to determine the value of MMAR in predicting a culprit lesion, with an area-under-the-curve analysis for MMAR predicting a culprit lesion of 0.68. Conclusions: MMAR is larger for lesions that will versus will not become culprit at the time of future ACS. The addition of MMAR in the assessment of CAD on CCTA may help stratify the risk of individual coronary lesions.