CT-based Volume Measurement of Brain Calcification Is Related to Clinical Symptoms and Disease Progression in Primary Familial Brain Calcification

PURPOSE: Primary Familial Brain Calcification (PFBC) is a disorder characterized by basal ganglia calcification. A CT visual rating scale known as the Total Calcification Score (TCS) is often used to quantify brain calcification, but volume measurements are a novel approach. This study evaluated the association between the (modified) TCS, volume measurements, and clinical symptoms, and their ability to detect calcification progression.

METHODS: In patients with PFBC, the (modified) TCS and volumes were calculated for each brain CT. Clinical symptoms were assessed using the Montreal Cognitive Assessment (MoCA), Unified Parkinson's Disease Rating Scale (UPDRS), and Neuropsychiatric Inventory-Questionnaire (NPI-Q). Calcification progression was determined for patients with a second CT available. Annual median progression rates were calculated.

RESULTS: Of the 66 included patients (median age 60 years, 56% male), 26 had a follow-up CT after 1 year (IQR 0.5-1.3 year). The median TCS was 28.5, modified TCS was 32.5, and volume was 7.6 cm 3. Volume measurements showed a significant association with clinical symptoms (MoCA β = -0.44[SE 0.02] and UPDRS β = 0.61[SE 0.04]), comparable to the (modified) TCS, and accounted for the largest proportion of explained variance (MoCA R 2 = 0.19, UPDRS R 2 = 0.37). There were no significant associations between the methods and NPI‑Q. Volume measurements showed an annual progression rate of 6.2%, whereas the (modified) TCS showed no annual change.

CONCLUSION: Volume measurements of brain calcification were significantly associated with clinical symptoms, explained more variance, and appeared in this small sample to be better in detecting calcification progression compared with visual scores, although further diagnostic and longitudinal testing is required.