No abstract

Serial MRI studies are used to analyse change in multiple sclerosis (MS) lesion volume in clinical trials. As such an evaluation is very time consuming and subject to quantification errors, one might assess only the change in number or size of lesions using subtracted images. The advantage of subtracted images is that both new and/or enlarging and resolving and/or shrinking lesions can be evaluated, resulting in a more precise volume change than a net volume change. We studied the interobserver agreement in the detection of active MS lesions using paired dual-echo T(2)-weighted spin-echo studies (3-mm slices) of 30 MS patients with a range of MS disease activity on MRI from treatment trials. Using an automatic matching algorithm based on mutual information, the follow-up scan was registered to baseline, after which subtracted images were obtained. After a training session with formulation of guidelines, six observers identified new, enlarging, resolving and shrinking lesions on subtracted images. Weighted kappa (kappa) values were calculated to assess interobserver agreement. Good agreement was found for new lesions (kappa 0.69 +/- 0.08), while moderate agreement was found for enlarging lesions (kappa 0.52 +/- 0.06). When new and enlarging lesions were combined, good agreement was found for "positive" activity (kappa 0.71 +/-0.06). The interobserver agreement was poor for resolving lesions (kappa 0.31 +/- 0.07), and moderate for shrinking lesions (kappa 0.53 +/- 0.08). In conclusion, the use of subtracted images in the visual detection of new T(2) lesions resulted in a good level of interobserver agreement for "positive" disease activity. Subtraction of registered images is a reliable, time efficient method to assess disease progression in MS.

The application of image registration and subtraction to detect change in multiple sclerosis (MS) disease burden on serial MR scans benefits from the use of isotropic voxels. An optimised 3D fast fluid-attenuated inversion recovery (FLAIR) sequence with 1.2- and 1.8-mm cubic voxels was compared with a 2D T2 SE sequence using standard 3-mm slices. Three-dimensional fast FLAIR and T2 SE series were obtained in 20 MS patients and 15 controls. Whole brain acquisition times for the 1.2- and 1.8-mm FLAIR were 21 and 10.5 min, respectively, for the interleaved T2 SE 16 min. Brain lesions were marked in consensus by two radiologists and the CNR was calculated in ten lesions. The mean number of lesions detected with the 1.2-mm FLAIR sequence was 115 +/- 76, compared with 85 +/- 59 for the T2 SE series ( p<0.001). The 1.8-mm FLAIR detected only 73 +/- 46 lesions. The CNR of the 1.2-mm FLAIR was significantly better than the T2 SE ( p<0.01), but not as good as the 1.8-mm FLAIR. In conclusion, isotropic 3D fast FLAIR using 1.2-mm cubic voxels is superior to the 2D T2 SE in the detection of brain lesions in MS patients. The isotropic 1.8-mm FLAIR is faster and has better contrast characteristics but lacks sensitivity.

Due to an unexpected increase in serious cardiovascular events in MS patients treated with Linomide, a synthetic immunomodulator, two phase-III multinational relapsing remitting (RR) and secondary progressive (SP) MS trials had to be discontinued. MRI results of 413 patients who participated for at least 3 months were analysed. Patients received placebo, 2.5 or 5 mg Linomide. Scans were performed at pre-enrolment, month 3 and termination. The number and volume of enhancing lesions (ELV), and the number of active scans were evaluated. At month 3, the decrease in the number of enhancing lesions in the placebo group was 11%, compared with 15% in the 2.5 mg group (P=0.027) and 23% in the 5 mg group (P=0.057). Using the percentage of active scans as outcome parameter, the odds ratio for improvement between placebo and 2.5 mg group was 1.62 (P=0.14); between placebo and 5 mg Linomide group 3.58 (P=0.003). At termination, a rebound effect was noted in the 2.5 mg group (P=0.01). Analysis of the ELV showed no significant difference between placebo and treatment groups. Although Linomide has unacceptable side effects, it seems to have a modest effect on MS disease activity, as measured by MRI. Multiple Sclerosis (2000) 6, 99 - 104

Endovaginal MR imaging clearly demonstrates the anatomy of the female pelvic floor and urethra.