Characteristics of symptomatic chronic subdural haematomas on high-field MRI

We studied the frequency of various features of the appearances on high-fie ld MRI in symptomatic patients with chronic subdural haematomas (CSDH). The ability to predict recurrence after treatment with one burr-hole procedure using MRI was evaluated. A total of 40 patients with symptomatic CSDH unde rwent MRI at 1.5 T. All haematomas were evacuated within a few days of the MRI examination. Symptomatic CSDH were divided into five groups according t o the MRI findings: group A (II cases), isointense or low signal on T1- and low signal on T2-weighted images; group B (18 cases), high signal on T1- a nd low signal on T2-weighted images; group C (5 cases), high signal on both T1- and T2-weighting; group D (1 case), low signal on T1- and high signal on T2-weighted images; group E (5 cases), heterogeneous intensity on T1- an d T2-weighting throughout the haematoma cavity. The mean interval between o nset of symptoms and MRI for group A was 5.0 +/- 4.1 days, which was signif icantly shorter than that for group B (9.4 +/- 4.4 days, P < 0.02), group C (27.8 +/- 20 days, P < 0.005) or group E (17.8 +/- 12.2 days, P < 0.01). R ecurrence was seen in three haematomas of group A and one of group B. Reope ration was most closely correlated with diffuse low signal on T2-weighted i mages but not with a multiloculated appearance. Low signal on T2 weighting was surprisingly high (72.5 %) and the age of the haematomas as estimated o n the MRI correlated well with the interval between the onset of symptoms a nd MRI. Our findings support the causative role of recurrent bleeding in th e enlargement of CSDH.