QUANTITATIVE MRI OF UTERINE LEIOMYOMAS DURING TRIPTORELIN TREATMENT -REPRODUCIBILITY OF VOLUME ASSESSMENT AND PREDICTABILITY OF TREATMENT RESPONSE

Magnetic resonance (MR) imaging is increasingly applied for the quanti tative evaluation of uterine leiomyomas, MR is thought to be more accu rate in comparison to ultrasound (US) techniques, MR signal intensity (SI) may prove to be predictive of myoma response to GnRH agonist trea tment, This study aimed to evaluate the precision of uterine volume as sessment by a parallel planimetric MR method and the accuracy of the e llipsoid formula based calculations from MR and US images, It was also attempted to analyze the precision of MR leiomyoma volume measurement s and examine the relation between pretreatment myoma SI patterns and the response to agonist therapy, Twenty-seven women with a myomatous u terus were scanned three times during GnRH agonist treatment for 6 mon ths, T-1- and T-2-weighted, as well as T-1 contrast-enhanced sequences of the uterus were obtained in the transverse and sagittal plane, Abd ominal US of the uterus was performed with a conventional sector scann er, By the use of a software system for analysis of three-dimensional images obtained by MR, uterine volume was measured by a parallel plani metric method (MR-ROI) as well as the use of the ellipsoid formula (MR -ELL), Myoma volume was assessed by the MR-ROI method, SI of the myoma s was estimated from selected tissue samples as well as from the integ ral myoma region of interest, By abdominal US, volume was assessed by the ellipsoid equation (US-ELL), Within- and between-observer and meth od reliability (Rw/Rb) was calculated from mean squares obtained by an alysis of variance, For uterine volume assessment, reliability between observers and between methods when the MR-ROI and MR-ELL methods were analyzed was excellent, For the US-ELL measurements, the between-obse rver reliability was limited, Moreover, the reliability of the US-ELL was low when the MR-ROI method was used as the standard. Myoma volume assessment with the MR-ROI method showed high between-observer and bet ween-method agreement. The myoma/fat SI ratio and the mean SI coeffici ent of variation failed to show a correlation with the degree of respo nse to triptorelin treatment of individual myomas, In MR uterine volum e assessment the MR-ELL method is very accurate compared with the more complicated MR-ROI method, The agreement between MR and US is limited , Therefore, the ellipsoid method on MR images is to be regarded as th e method of choice for quantitative assessment of uterine volume respo nse to hormonal treatment, Myoma SI patterns were shown to be of no va lue in the response prediction of myomas to treatment with GnRH agonis ts. Copyright (C) 1996 Elsevier Science Inc.