Role of Dynamic MRI in the follow-up of acute Charcot foot in patients with diabetes mellitus

Abstract

To evaluate the usefulness of magnetic resonance imaging (MRI) in assessing the level of activity of acute Charcot foot, monitoring treatment response and predicting healing time. Forty diabetic patients with acute Charcot foot were prospectively enrolled. Patients underwent limb immobilization and were followed every 3 months by clinical examination (skin temperature and circumferences) and MRI. MR protocol included T1-weighted and fast spin echo inversion recovery (FSE-IR) sequences, and a dynamic study (fast spoiled gradient echo), after gadolinium administration (0.1 ml/kg). The contrast medium uptake rate at D-MRI and the signal intensity (SI) ratio on the FSE-IR sequence were measured. At baseline, mean contrast medium uptake rate was 136 ± 49.7% and the mean SI ratio was 5 ± 3. A high intra- and inter-observer agreement was found for the contrast medium uptake rate, whereas a low agreement was observed for the SI ratio. At 3 months' follow-up, reduction of the contrast medium uptake rate was observed in all patients with improved clinical findings (n = 34), whereas the SI ratio was reduced in 15/34 (44.1%) patients. Mean healing time was significantly related to the baseline contrast medium uptake rate (P=0.005); it was 5.3 ± 2.7 months in patients with contrast medium uptake rate ≤ 100%, compared with 9.1 ± 2.5 months in the remaining patients (P=0.0003). Contrast medium uptake rate obtained at D-MRI represents a reproducible parameter that is reliable for predicting and monitoring treatment outcome in acute Charcot foot.