Fibroid volume

It is important to evaluate the uterine and fibroid volumes as patients that show poor reductions in uterine volume post embolization may be more likely to require hysterectomy [4]. MR not only provides easily understood images that can be shown to patients, but also information that can be used to predict future fibroid shrinkage or to predict regrowth and possible further therapy. 

With the growing popularity of uterine fibroid embolization (UFE), the scientific evidence has also greatly improved. Evaluation of results associated with UFE has included clinical success rate and uterine/fibroid volume reduction. Cost, recovery time, change in quality-of-life and patient acceptance are other important considerations. The associated risks of complications associated with UFE are of paramount importance before offering this procedure to young women interested in future fertility. 

In addition, the degree of gadolinium enhancement is not correlated with fibroid volume reduction [35, 37]. Therefore, these data suggest that ultrasound may not be useful for the imaging follow-up particularly in patients who have recurrent symptoms [37]. This observation may change if a more accurate means than color Doppler is developed to assess residual fibroid perfusion with ultrasound [38,39]. 

Fibroid location within the uterus may influence the outcome of embolization. Submucosal fibroids were more likely to respond to UFE [20]. Submucosal location was a positive predictor of fibroid volume reduction after UFE [21]. The subserosal fibroids are also believed to be associated with less volume reduction after embolization (Fig. 10.5.6). 

In a prospective study in 77 consecutive women with postmenopausal breast cancer scheduled to start endocrine treatment for breast cancer, using either tamoxifen or an aromatase inhibitor tamoxifen treatment significantly increased endometrial thickness and uterine volume after 3 months (24). In additional, tamoxifen induced endometrial cysts and polyps and increased the size of pre-existing fibroids. In contrast, aromatase inhibitors did not stimulate endometrial growth and were not associated with endometrial pathology. Furthermore, they reduced endometrial thickness and uterine volume in patients who had previously taken tamoxifen. 

MRI-guided focused ultrasound fibroid ablation is the newest of the non-invasive techniques and is still in the experimental stages. The ultrasound waves are directed from a transducer into a small focal volume. The tissue at the focal point receives condensed energy and increases in temperature, causing protein denaturation, cell death and coagu-lative necrosis. While a commercial device is available, long term data on this procedure does not yet exist [45]. 

The best imaging to evaluate the perfusion and size/ volume of the fibroids following the procedure is MR. The timing of the imaging is not standardized. In our practice we typically image at 6 months which gives a chance for the fibroids to have changed in volume and offers the patient an opportunity to... 

Although there are theoretical advantages to the use of Embospheres, clinical studies have not shown an advantage over PVA particles [27]. The volume decrease ofthe fibroids, and the uterine volume reduction is similar between Embospheres and PVA [54]. The volume of microspheres required for an embolization is larger than the volume of PVA required to complete an embolization [27]. In both retrospective and prospective study there does not seem to be a difference in post procedure pain or the use of narcotic use between PVA and microspheres [27,55]. 

Fig. 10.4.1a,b. A 39-year-old woman with fibroid-related menorrhagia and pelvic pressure, a Pre-embolization sagittal T2-weighted MRI demonstrates a multifibroid uterus, b Post-embolization sagittal T2-weighted MRI obtained 6 months after embolization demonstrates a marked volume reduction of 55%. The patient s condition has also greatly improved... 

Using three-dimensional color Doppler sonography, Fleischer et al. [36] found that hypervascular fibroids tend to decrease in size after UFE more than their isovascular or hypovascular fibroids. McLu-CAS et al. [15] showed that the initial peak systolic velocity was positively correlated with the shrinkage of fibroids and uterine volume reduction. 

In addition to volume reduction, the detection of new fibroids should be a priority since it is very common with other uterus-sparing therapies [20]. The remaining question is the duration between UFE and clinical recurrence due to new fibroids and whether this interval is different from that seen after myomectomy. 

Fig. 10.4.6a,b. A 36-year-old woman with bulk-related symptoms, a Pre-embolization sagittal T2 weighted MRI shows a large pedunculated subserosal fibroid (F). b At 6 months post-embolization MRI shows a degenerative fibroid (F) with no volume reduction. The patient ultimately required myomectomy... 

Fig. 10.5.6a,b. Patient with a 6-cm subserosal fibroid before and after embolization, a MRl before embolization shows a large sub-serosal fibroid, b Enhanced MRI obtained 6 months after embolization demonstrates no volume change with persistent uptake... 

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