Abstract
Lateral ventricular enlargement has been consistently reported as a neuroimaging finding in schizophrenia since the CT era. The advancement from CT to MRI technology has dramatically improved the precision of quantitative assessment of lateral ventricle volume (LVV) . The lateral ventricles reflect the volumetric status of surrounding structures such as the hippocampus, caudate nucleus, and thalamus, functioning as a “negative image” of gray and white matter. LVV enlargement is observed even in first‐episode patients, suggesting neurodevelopmental abnormalities, while progressive enlargement after onset indicates neurodegenerative processes. However, heterogeneity exists, with some patients showing rapid enlargement and others demonstrating shrinkage. The development of automated analysis technologies such as FreeSurfer, SAMSEG, and SynthSeg has enabled evaluation from clinical data. In Japan’s COCORO project, the EVCI subtype, characterized by prominent ventricular enlargement and cognitive impairment, has been identified, accounting for approximately 10‐20% of schizophrenia patients. This subtype shows associations with treatment resistance and potential utility as an indicator for early clozapine introduction. A major challenge for clinical implementation is distinguishing pathological enlargement from age‐related changes, making normative modeling essential. LVV is expected to serve as a biomarker enhancing diagnostic objectivity and guiding treatment optimization in psychiatric disorders.
