MRI analysis of uterine ischaemia as a form of non-target embolisation following uterine artery embolisation: incidence, extent and outcome

AIM

To study the incidence, extent and fate of uterine ischaemia as one of the forms of non-target embolisation following uterine artery embolisation (UAE), as detected on immediate post-embolisation and contrast-enhanced magnetic resonance imaging (MRI) examinations at the 3-month follow-up.

MATERIALS AND METHODS

A retrospective study was undertaken comprising 43 women (mean age: 44.8 ± 3.79 years). MRI was performed before, immediately after (within 6 h), and 3 months after successful UAE. Areas of uterine ischaemia were identified on immediate post-embolisation MRI as regions of newly developed (compared to pre-embolisation MRI) absent enhancement within the uterus not corresponding to the location of the leiomyoma. The volume of the ischaemic region was calculated using the formula (height × length × width × 0.523).

RESULTS

Uterine ischaemia was encountered in 29 patients (67.44%). The mean volume of the ischaemic region immediately after UAE was 29.29 ± 19.15 ml (range: 7.36-87.71 ml). At 3-month follow-up, it was 0.35 ± 0.95 ml (range: 0-3.5 ml) with 25 (86%) patients showing complete resolution of the ischaemia. The mean reduction in the volume of the ischaemic region at the 3-month follow-up was 98.24 ± 5.72% (range: 72-100%). This volume reduction was statistically significant (p<0.0001).

CONCLUSION

Uterine ischaemia as a form of non-target embolisation following UAE might be encountered in up to two thirds of patients. These ischaemic areas are significantly reduced at the 3-month follow-up with up to 86% of cases showing complete reversibility of the ischaemia.

Acute intracranial hemorrhage in CT: benefits of sinogram-affirmed iterative reconstruction techniques

BACKGROUND AND PURPOSE

Acute intracranial hemorrhage represents a severe and time critical pathology that requires precise and quick diagnosis, mainly by performing a CT scan. The purpose of this study was to compare image quality and intracranial hemorrhage conspicuity in brain CT with sinogram-affirmed iterative reconstruction and filtered back-projection reconstruction techniques at standard (340 mAs) and low-dose tube current levels (260 mAs).

MATERIALS AND METHODS

A total of 94 consecutive patients with intracranial hemorrhage received CT scans either with standard or low-dose protocol by random assignment. Group 1 (n=54; mean age, 64 ± 20 years) received CT at 340 mAs, and group 2 (n=40; mean age, 57 ± 23 years) received CT at 260 mAs. Images of both groups were reconstructed with filtered back-projection reconstruction and 5 iterative strengths (S1-S5) and ranked blind by 2 radiologists for image quality and intracranial hemorrhage on a 5-point scale. Image noise, SNR, dose-length product (mGycm), and mean effective dose (mSv) were calculated.

RESULTS

In both groups, image quality and intracranial hemorrhage conspicuity were rated subjectively with an excellent/good image quality. A higher strength of sinogram-affirmed iterative reconstruction showed an increase in image quality with a difference to filtered back-projection reconstruction (P < .05). Subjective rating showed the best score of image quality and intracranial hemorrhage conspicuity achieved through S3/S4-5. Objective analysis of image quality showed in an increase of SNR with a higher strength of sinogram-affirmed iterative reconstruction. Patients in group 2 (mean: 744 mGycm/1.71 mSv) were exposed to a significantly lower dose than those in group 1 (mean: 1045 mGycm/2.40 mSv, P < .01).

CONCLUSIONS

S3 provides better image quality and visualization of intracranial hemorrhage in brain CT at 260 mAs. Dose reduction by almost one-third is possible without significant loss in diagnostic quality.

Role of uterine artery Doppler in the management of uterine leiomyoma by arterial embolization

OBJECTIVES

To study Doppler changes in the uterine artery immediately following and 3 months after uterine artery embolization (UAE) and to test the feasibility of using uterine artery Doppler as a predictor of the predominant side of arterial supply to leiomyomas, amount of embolizing material needed and leiomyoma tumor volume at follow-up.

METHODS

The study included 38 patients undergoing UAE for leiomyomas. Uterine artery Doppler was performed transabdominally before, within 6 hours after and 3 months after UAE to determine the peak systolic (PSV) and end-diastolic (EDV) velocities and resistance index (RI). Leiomyoma volume was measured using contrast-enhanced magnetic resonance imaging (MRI) before and 3 months after UAE. The predominant side of arterial supply to the leiomyoma was determined on digital subtraction angiography using the uterine artery diameter and tumor blush after contrast injection. For correlations with leiomyoma volume, the average PSV, EDV and RI of both sides was used, while for prediction of the predominant side of supply and for correlation with the amount of embolizing material needed, separate measurements from each side were used.

RESULTS

Relative to the pre-embolization value, the uterine artery PSV and EDV were significantly reduced (P < 0.05) immediately following UAE, while the RI was significantly elevated (P < 0.05). For prediction of the predominant side of supply, the lowest RI showed the highest accuracy (81.6%). There was no significant correlation between the pre-embolization PSV, EDV or RI and the amount of embolizing material utilized. Immediately post-embolization EDV and RI values were statistically significantly correlated with the 3-month follow-up leiomyoma volume, with RI showing the strongest correlation (P = 0.0400 and 0.0002, rho = 0.34 and - 0.58, respectively). The leiomyoma volume was predicted to have reduced by 38-61% after 3 months if the immediate post-embolization average RI value was between 0.82 and 0.88.

CONCLUSION

Pre-interventional Doppler assessment can be used to predict the predominant side of supply to leiomyomas but not the amount of embolizing material needed. Immediate post-interventional Doppler assessment can predict the leiomyoma volume after UAE.