Time course of osteoporotic vertebral fractures by magnetic resonance imaging using a simple classification: a multicenter prospective cohort study.

Abstract

Magnetic resonance imaging (MRI) is useful in diagnosing osteoporotic vertebral fractures (OVFs). This study investigated the time course of OVFs by MRI using a simple classification. This multicenter cohort study was performed from 2012 to 2015. Consecutive patients with ≤2-week-old OVFs were enrolled in 11 institutions. MRI was performed at enrollment and at 1-, 3-, 6-, and 12-month follow-up. Signal changes on T1-weighted imaging (T1WI), T2WI, and short τ inversion recovery (STIR) were classified according to signal intensity. Height and angular motion of vertebral bodies were also measured. The 6-month follow-up was completed by 153 patients. At enrollment, fractured vertebrae signal changes were 43% diffuse and 57% confined low on T1WI; on T2WI, 56, 24, and 5% were confined low, high, and diffuse low, respectively; on STIR, 100% were high. On T1WI, diffuse low remained most common (90% at 1month and 60% at 3months) until 6 and 12months, when most were confined low (54 and 52%, respectively). On T2WI, confined low remained most common (decreasing to 41% at 12months). On STIR, high signal change was shown in 98, 87, and 64% at 3, 6, and 12months, respectively. At 3, 6, and 12months, diffuse low signal change was associated with significantly lower vertebral height, and high signal change was associated with significantly greater angular motion. MRI signal changes were associated with the compression degree and angular motion of fractured vertebrae. This classification showed sufficient reliability in categorizing MRI findings of OVFs.