Use of the results of dynamic contrast-enhanced magnetic resonance imaging for choosing the optimal size of embolic material for the endovascular treatment of uterine myoma

Objective. To elaborate an algorithm for choosing the size of embolic material for uterine artery embolization (UAE) in patients with uterine myoma. Subjects and methods. The investigation included 63 patients. All the patients underwent bolus contrast-enhanced magnetic resonance imaging (MRI) and further estimation of the contrast medium in the myomatous nodules. According to the type of a kinetic curve for the contrast agent in relation to the intact myometrium, all myomatous nodules were classified into three types: I) a hypovascular nodule; II) a nodule with moderate vascularization; III) a hypervascular nodule. According to the size of the embolic material used, the patients were randomized into two groups of those who received calibrated polyvinyl microspheres 500-700 or 700-900 μm in size. In all the cases, bilateral UAE was performed through right-sided transfemoral approach, followed by MRI evaluation of the efficiency of the procedure. Results. All the patents underwent technically successful bilateral UAEs. Preoperative MRI assigned 188 (57%) of 330 detected myomatous nodules to type I, 73 (22.1%) to type II, and 69 (20.9%) to type III. The type distribution of myomatous nodules was 107, 33, and 41 in Group 1; and it was 81, 40, and 28 in Group 2. According to MRI data, the direct efficiency of UAE was 96.7 and 88.6% in Group 1 and 2, respectively. In accordance with the perfusion types (I, II, and III) of myomatous nodules, the efficiency of embolization was 99.1, 93.9, and 92.7% in Group 1 and 96.3, 95, and 57.1% in Group 2. In Groups 1 and 2, the severity of pain syndrome averaged 4.1±2.1 and 3.1±3.0 scores, respectively. In these groups, the need for narcotic analgesics in the first 24 hours postsurgery was 28.1 and 12.9%, respectively. The amount of spent embolic material averaged 7.8±1.9 and 5.4±2.8 ml in Groups 1 and 2, respectively. Conclusion. The calibrated spherical embolic material 700-900 μm in size versus that 500-700 μm in size showed a low efficacy in type III myomatous nodules. Embolic material with smaller embolic particles should be used in patents with type III (hypervascular) myomatous nodules found preoperatively by MRI. That with larger particles should be applied to patients without myomatous nodules to reduce the intensity of pain syndrome.

uterine myoma, uterine artery embolization, contrast-enhanced magnetic resonance imaging, hypovascular nodule, hypervascular nodule, size of embolic particles