Uterine artery embolization: optimization with preprocedural prediction of the best tube angle obliquity by using 3D-reconstructed contrast-enhanced MR angiography

Review of uterine fibroids: imaging of typical and atypical features, variants, and mimics with emphasis on workup and FIGO classification

Uterine fibroids are the most common gynecologic neoplasm. Although non-degenerated fibroids are easily identifiable on imaging, degenerated fibroids, fibroid variants, and fibroids with unusual growth patterns can constitute a diagnostic dilemma. Identification of these abnormal morphologic features can alter the diagnosis of presumed uterine fibroids and hence change management plans. This article reviews the typical and atypical radiologic imaging features of uterine fibroids, with an emphasis on the pitfalls, mimics, and radiologically identifiable features that can alter clinical management plans.

MR Angiography Series: Abdominal and Pelvic MR Angiography

This review guides readers through the selection and setup of standardized MR angiography (MRA) protocols for the abdomen and pelvis for common clinical applications. Topics covered include renovascular MRA in potential kidney donors and in patients with hypertension; hepatic and mesenteric MRA in potential liver donors, patients with portal hypertension, and patients with chronic mesenteric ischemia; pelvic MRA for pretreatment planning before uterine fibroid embolization and in patients with pelvic congestion syndrome; and abdominal wall MRA for planning of breast reconstructive surgery. This module is the fifth in a series created on behalf of the Society for Magnetic Resonance Angiography (SMRA), a group of researchers and clinicians who are passionate about the benefits of MRA but understand its challenges. The full digital presentation is available online. ^©RSNA, 2022.

MR angiography-planned prostatic artery embolization for benign prostatic hyperplasia: single-center retrospective study in 56 patients

PURPOSE

We aimed to evaluate the advantages of magnetic resonance angiography (MRA)-planned prostatic artery embolization (PAE) for benign prostatic hyperplasia (BPH).

METHODS

In this retrospective study, MRAs of 56 patients (mean age, 67.23±7.73 years; age range, 47-82 years) who underwent PAE between 2017 and 2018 were evaluated. For inclusion, full information about procedure time and radiation values must have been available. To identify prostatic artery (PA) origin, three-dimensional MRA reconstruction with maximum intensity projection was conducted in every patient. In total, 33 patients completed clinical and imaging follow-up and were included in clinical evaluation.

RESULTS

There were 131 PAs with a second PA in 19 pelvic sides. PA origin was correctly identified via MRA in 108 of 131 PAs (82.44%). In patients in which MRA allowed a PA analysis, a significant reduction of the fluoroscopy time (-27.0%, p = 0.028) and of the dose area product (-38.0%, p = 0.003) was detected versus those with no PA analysis prior to PAE. Intervention time was reduced by 13.2%, (p = 0.25). Mean fluoroscopy time was 30.1 min, mean dose area product 27,749 µGy•m2, and mean entrance dose 1553 mGy. Technical success was achieved in all 56 patients (100.0%); all patients were embolized on both pelvic sides. The evaluated data documented a significant reduction in IPSS (p < 0.001; mean 9.67 points).

CONCLUSION

MRA prior to PAE allowed the identification of PA in 82.44% of the cases. MRA-planned PAE is an effective treatment for patients with BPH.

Comparison of 1.5 T and 3 T non-contrast-enhanced MR angiography for visualization of uterine and ovarian arteries before uterine artery embolization

OBJECTIVES

This study aimed to compare the performance of non-contrast-enhanced magnetic resonance angiography (NCE-MRA) at 1.5 T and 3 T for the visualization of uterine and ovarian arteries (OAs) before uterine artery embolization (UAE).

METHODS

Preprocedural pelvic NCE-MRA images of 85 symptomatic patients undergoing UAE for the treatment of uterine leiomyomas were reviewed by two specialists in pelvic MRI. Left and right uterine arteries (UAs) were judged separately and scored on a 5-point scale. Score 5 was the highest, in which the UA could be visualized inside the musculature, forming a peritumoral plexus. Score 1 was the lowest, where visualization was limited to the descending segment. The detection of enlarged OAs was also compared. The Mann-Whitney U and Fisher exact tests were used for statistical analysis. p < 0.05 was considered to be statistically significant.

RESULTS

Of the 170 UAs, 110 were classified at 1.5 T and 60 were classified at 3 T. Median (interquartile range [IQR]) score was 3 (IQR: 2-4) for visualization at 1.5 T vs 5 (IQR: 4-5) for 3 T. The scores for UA visualization were significantly higher at 3 T (p < 0.05). For enlarged OAs, NCE-MRA at 1.5 T and 3 T visualized 7 and 5 enlarged OAs, respectively; there was no significant difference between the two field strengths (p = 0.36).

CONCLUSIONS

NCE-MRA performed at 3 T can visualize UAs over a greater range than at 1.5 T. No difference was found regarding the detection of enlarged OAs.

KEY POINTS

• Preprocedural MRA can provide interventional radiologists with valuable information, including the origin and course of the uterine arteries and the existence of collateral feeders to the tumor. • This study demonstrates the superiority of non-contrast-enhanced MRA performed at 3 T over that performed at 1.5 T in the visualization of the uterine arteries in patients undergoing uterine artery embolization for the treatment of uterine leiomyomas. • Non-contrast-enhanced MRA is a useful imaging modality for patients with symptomatic leiomyoma undergoing uterine artery embolization in whom contrast administration is unfeasible. If available, it is preferable to perform the examination with a 3 T MR unit rather than a 1.5 T MR unit.

Morphological and functional assessment of the uterus: "one-stop shop imaging" using a compressed-sensing accelerated, free-breathing T1-VIBE sequence

BACKGROUND

The combination of motion-insensitive, high-temporal, and spatial resolution imaging with evaluation of quantitative perfusion has the potential to increase the diagnostic capabilities of magnetic resonance imaging (MRI) in the female pelvis.

PURPOSE

To compare a free-breathing compressed-sensing VIBE (fbVIBE) with flexible temporal resolution (range = 4.6-13.8 s) with breath-hold VIBE (bhVIBE) and to evaluate the potential value of quantifying uterine perfusion.

MATERIAL AND METHODS

A total of 70 datasets from 60 patients (bhVIBE: n = 30; fbVIBE: n = 40) were evaluated by two radiologists. Only temporally resolved reconstruction (fbVIBE) was performed on 30 of the fbVIBE datasets. For a subset (n = 10) of the fbVIBE acquisitions, a time- and motion-resolved reconstruction (mrVIBE) was evaluated. Image quality (IQ), artifacts, diagnostic confidence (DC), and delineation of uterine structures (DoS) were graded on Likert scales (IQ/DC/DoS: 1 (non-diagnostic) to 5 (perfect); artifacts: 1 (no artifacts) to 5 (severe artifacts)). A Tofts model was applied for perfusion analysis. Ktrans was obtained in the myometrium (Mm), junctional zone (Jz), and cervix (Cx).

RESULTS

The median IQ/DoS/DC scores of fbVIBE (4/5/5 κ >0.7-0.9) and bhVIBE (4/4/4; κ = 0.5-0.7; P > 0.05) were high, but Artifacts were graded low (fbVIBE/bhVIBE: 2/2; κ = 0.6/0.5; P > 0.05). Artifacts were only slightly improved by the additional motion-resolved reconstruction (fbVIBE/mrVIBE: 2/1.5; P = 0.08); fbVIBE was preferred in most cases (7/10). Significant differences of Ktrans values were found between Cx, Jz, and Mm (0.12/0.21/0.19; P < 0.05).

CONCLUSION

The fbVIBE sequence allows functional and morphological assessment of the uterus at comparable IQ to bhVIBE.

The CIREL Cohort: A Prospective Controlled Registry Studying the Real-Life Use of Irinotecan-Loaded Chemoembolisation in Colorectal Cancer Liver Metastases: Interim Analysis

PURPOSE

Transarterial chemoembolisation (TACE) using irinotecan-eluting beads is an additional treatment option for colorectal cancer liver metastases (CRLM) patients that are not eligible for curative treatment approaches. This interim analysis focuses on feasibility of the planned statistical analysis regarding data distribution and completeness, treatment intention, safety and health-related quality of life (HRQOL) of the first 50 patients prospectively enrolled in the CIrse REgistry for LifePearl™ microspheres (CIREL), an observational multicentre study conducted across Europe.

METHODS

In total, 50 patients ≥ 18 years diagnosed with CRLM and decided to be treated with irinotecan-eluting LifePearl™ microspheres TACE (LP-irinotecan TACE) by a multidisciplinary tumour board. There were no further inclusion or exclusion criteria. The primary endpoint is the categorisation of treatment intention, and secondary endpoints presented in this interim analysis are safety, treatment considerations and HRQOL.

RESULTS

LP-irinotecan TACE was conducted in 42% of patients as salvage therapy, 20% as an intensification treatment, 16% as a first-line treatment, 14% a consolidation treatment and 8% combination treatment with ablation with curative intent. Grade 3 and 4 adverse events were reported by 4% of patients during procedure and by 10% within 30 days. While 38% reported a worse, 62% reported a stable or better global health score, and 54% of patients with worse global health score were treated as salvage therapy patients.

CONCLUSION

This interim analysis confirms in a prospective analysis the feasibility of the study, with an acceptable toxicity profile. More patients reported a stable or improved HRQOL than deterioration. Deterioration of HRQOL was seen especially in salvage therapy patients.

TRIAL REGISTRATION

NCT03086096.

Effectiveness of Contrast-enhanced MR Angiography for Visualization of the Prostatic Artery prior to Prostatic Arterial Embolization

Background A major technical challenge of prostatic arterial embolization (PAE) is the identification and catheterization of the prostatic arteries (PAs). Recently, MR angiography has been shown to help visualize PAs, but the clinical utility of MR angiography for this purpose is not known. Purpose To determine the efficacy of contrast material-enhanced MR angiography in identifying the PA and to evaluate its role in PAE for benign prostatic hyperplasia (BPH). Materials and Methods In this prospective study, 100 consecutive men who were scheduled to undergo PAE for BPH from January 2015 to May 2017 were assigned by using a randomized block design to either group A (n = 50; mean age, 71.7 years ± 11.9 [standard deviation]) without MR angiography or group B (n = 50; mean age, 72.3 years ± 12.2) with MR angiography prior to PAE. MR angiography findings of the PA anatomy were compared with those of digital subtraction angiography (DSA). The Student t test and Wilcoxon rank-sum test were used to compare the differences between the parameters indicating the performance of PAE. Results The mean age of the 100 men in the study was 72.0 years ± 11.8 (range, 51-88 years). Compared with DSA as the reference standard, MR angiography identified PAs with a sensitivity of 91.5% (97 of 106) and a positive predictive value of 100% (97 of 97). With the knowledge of tube obliquity and anatomy, group B had lower procedure times than group A (82.3 minutes ± 5.4 vs 123.9 minutes ± 12.4, P < .001) and shorter fluoroscopy times (13.8 minutes ± 2.7 vs 28.5 minutes ± 8.0, P < .001). Additionally, radiation dose was reduced for group A versus group B, from a median of 920 to 339 mGy (P = .004). Conclusion Contrast-enhanced MR angiography can accurately show anatomy for the prostate arteries, leading to shorter prostatic artery embolization times and lower radiation dose than when preprocedural prostate MR angiography is not performed. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Prince in this issue.

European Society of Urogenital Radiology (ESUR) Guidelines: MR Imaging of Leiomyomas

OBJECTIVE

The aim of the Female Pelvic Imaging Working Group of the European Society of Urogenital Radiology (ESUR) was to develop imaging guidelines for MR work-up in patients with known or suspected uterine leiomyomas.

METHODS

Guidelines for imaging uterine leiomyomas were defined based on a survey distributed to all members of the working group, an expert consensus meeting at European Congress of Radiology (ECR) 2017 and a critical review of the literature.

RESULTS

The 25 returned questionnaires as well as the expert consensus meeting have shown reasonable homogeneity of practice among institutions. Expert consensus and literature review lead to an optimized MRI protocol to image uterine leiomyomas. Recommendations include indications for imaging, patient preparation, MR protocols and reporting criteria. The incremental value of functional imaging (DWI, DCE) is highlighted and the role of MR angiography discussed.

CONCLUSIONS

MRI offers an outstanding and reproducible map of the size, site and distribution of leiomyomas. A standardised imaging protocol and method of reporting ensures that the salient features are recognised. These imaging guidelines are based on the current practice among expert radiologists in the field of female pelvic imaging and also incorporate essentials of the current published MR literature of uterine leiomyomas.

KEY POINTS

• MRI allows comprehensive mapping of size and distribution of leiomyomas. • Basic MRI comprise T2W and T1W sequences centered to the uterus. • Standardized reporting ensures pivotal information on leiomyomas, the uterus and differential diagnosis. • MRI aids in differentiation of leiomyomas from other benign and malignant entities, including leiomyosarcoma.

Preprocedural MRI and MRA in planning fibroid embolization

This pictorial review aims to discuss and illustrate the up-to-date use of preprocedural magnetic resonance imaging (MRI) in selecting patients and planning uterine artery embolization (UAE). The merits of magnetic resonance angiography (MRA) in demonstrating the pelvic vasculature to guide UAE are highlighted. MRI features of fibroids and their main differential diagnoses are presented. Fibroid characteristics, such as location, size, and enhancement, which may impact patient selection and outcome, are presented based on recent literature. Pelvic arterial anatomy relevant to UAE, including vascular variants are illustrated, with conventional angiography and MRA imaging correlation. MRA preprocedural determination of the optimal projection angles for uterine artery catheterization is straightforward and constitutes an important strategy to minimize ionizing radiation exposure during UAE. A reporting template for MRI/MRA preassessement of UAE for fibroid treatment is provided.

Pre-operative Simulation of the Appropriate C-arm Position Using Computed Tomography Post-processing Software Reduces Radiation and Contrast Medium Exposure During EVAR Procedures

OBJECTIVE/BACKGROUND

The aim was to evaluate the feasibility and efficacy of a new method for pre-operative calculation of an appropriate C-arm position for iliac bifurcation visualisation during endovascular aortic repair (EVAR) procedures by using three dimensional computed tomography angiography (CTA) post-processing software.

METHODS

Post-processing software was used to simulate C-arm angulations in two dimensions (oblique, cranial/caudal) for appropriate visualisation of distal landing zones at the iliac bifurcation during EVAR. Retrospectively, 27 consecutive EVAR patients (25 men, mean ± SD age 73 ± 7 years) were identified; one group of patients (NEW; n = 12 [23 iliac bifurcations]) was compared after implementation of the new method with a group of patients who received a historic method (OLD; n = 15 [23 iliac bifurcations]), treated with EVAR before the method was applied.

RESULTS

In the OLD group, a median of 2.0 (interquartile range [IQR] 1-3) digital subtraction angiography runs were needed per iliac bifurcation versus 1.0 (IQR 1-1) runs in the NEW group (p = .007). The median dose area products per iliac bifurcation were 11951 mGy*cm² (IQR 7308-16663 mGy*cm²) for the NEW, and 39394 mGy*cm² (IQR 19066-53702 mGy*cm²) for the OLD group, respectively (p = .001). The median volume of contrast per iliac bifurcation was 13.0 mL (IQR: 13-13 mL) in the NEW and 26 mL (IQR 13-39 mL) in the OLD group (p = .007).

CONCLUSION

Pre-operative simulation of the appropriate C-arm angulation in two dimensions using dedicated computed tomography angiography post-processing software is feasible and significantly reduces radiation and contrast medium exposure.

Uterine artery embolization: pre- and post-procedural evaluation using magnetic resonance imaging

Magnetic resonance (MR) imaging has become the preferred method in assessing the uterus and pelvis prior to and following uterine artery embolization (UAE). The multiplanar imaging capabilities, increased spatial and contrast resolution, anatomic detail and assessment of fibroid viability that MR provides over ultrasound allows for accurate pre-treatment planning and post-treatment assessment. The purpose of this article is to demonstrate the use of MR in the selection of patients, anatomic evaluation and procedural planning before UAE, describe the use of MR in evaluating treatment response after UAE and illustrate the use of MR in identifying post-UAE complications. An understanding of these principles is essential in guiding appropriate therapy, determining treatment effectiveness and identifying associated complications before and after UAE.

2D versus 3D roadmap for uterine artery catheterization: impact on several angiographic parameters

BACKGROUND

Three-dimensional (3D) roadmap is a recently developed imaging technique used to guide diagnostic and interventional catheter-directed procedures and mainly evaluated for neurovascular procedures. Few data with regard to efficacy and radiation dose are currently available in literature.

PURPOSE

To evaluate the use of 3D roadmap technique as compared with the conventional two-dimensional (2D) roadmap for uterine artery catheterization and embolization during uterine fibroid embolization and assess the potential impact on radiation dose, contrast load, and total procedure time.

MATERIAL AND METHODS

In this prospective study, 40 patients were randomly assigned to the 2D or 3D roadmap technique for uterine artery catheterization. Demographic data, specifically the patient's age, weight, height, pelvic circumference, and total uterine and fibroid volume were recorded. Exposure parameters, contrast load, and procedure time were recorded and organ doses for ovaries and uterus were calculated.

RESULTS

Demographic data did not differ between the groups. Catheterization and embolization of both uterine arteries were feasible in all patients, although in one patient in the 3D group, a focal dissection of the proximal uterine artery occurred. No significant difference in estimated ovarian dose was found in the 3D versus 2D group (P = 0.07). Total procedure time was shorter in the 2D group (P = 0.01) and no difference in total contrast load was seen (P = 0.17).

CONCLUSION

Both roadmap techniques are effective imaging-guided tools for uterine artery catheterization, without difference in terms of radiation exposure or contrast load. The total procedure time is shorter in the 2D group.

Radiological anatomical study of the origin of the uterine artery

PURPOSE

To clarify the origin of the uterine artery and quantify its anatomical variants.

MATERIALS AND METHODS

We carried out a study based on dissections, intraoperative findings and retrospective analysis of arteriograms. Thirty female cadavers were dissected and bilaterally observed, with a total of 60 origins visualised. Fifty laparotomies were carried out during the treatment for pelvic neoplasms (100 origins observed) and 34 arteriograms performed for uterine fibroid embolisation were studied (58 origins visualised).

RESULTS

In total, 218 origins of the uterine artery were visualised. The uterine artery originated from a common trunk with the umbilical artery in 80.7% of cases. It arose separately from the internal iliac artery in 13.16% of cases and directly from the superior gluteal artery in 3.51% of cases. It branched from a common trunk with the internal pudendal artery in 1.75% of cases, whereas arose separately from the obturator artery in 0.88% of cases.

CONCLUSION

The uterine artery arose from a common trunk with the umbilical artery in the majority of the Caucasian population. Surgeons and radiologists should be aware of this mode of branching to facilitate surgery and interventional radiology and improve the safety of these procedures.

Live MR angiographic roadmapping for uterine artery embolization: a feasibility study

PURPOSE

To assess the feasibility of live magnetic resonance (MR) angiography roadmapping guidance for uterine artery (UA) embolization (UAE) for fibroid tumors.

MATERIALS AND METHODS

Twenty patients underwent UAE with live MR angiographic roadmapping. The pre-acquired MR angiography scan was coregistered with the live intraprocedural fluoroscopy stream to create a visual roadmap to direct the microcatheter during UAE. Patient radiation dose, as measured by dose-area product (DAP), procedure time, contrast medium volume, and fluoroscopy time, was recorded. For the first 10 patients, an additional parameter of contrast medium volume needed to catheterize each UA was recorded.

RESULTS

In all 20 patients (40 UAs), the MR angiography overlay on live fluoroscopy was accurate and allowed for successful catheterization of the UA, resulting in a technical success rate of 100%. In the subset of the initial 20 UAs (ie, the first 10 patients) in which this data point was recorded, 17 (85%) were successfully catheterized with no iodinated contrast medium at all, by purely relying on the MR angiography roadmap. Mean procedure time was 45 minutes (range, 30-99 min), mean contrast agent dose was 75 mL (range, 46-199 mL), and mean DAP was 155 Gy · cm(2) (range, 37-501 Gy · cm(2)).

CONCLUSIONS

Live MR angiographic roadmapping is feasible and accurate for catheter guidance during UAE.

Transjugular intrahepatic portosystemic shunt stent-graft placement: mean optimal portal venous projection view determined by three-dimensional portography

BACKGROUND

Suboptimal stent-graft placement at the lower anastomosis during transjugular intrahepatic portosystemic shunt (TIPS) may result in early shunt stenosis and occlusion owing to incomplete covering of the parenchymal tract by the covered part of the stent-graft.

PURPOSE

To determine the optimal portal venous projection view for stent-graft placement during TIPS and the potential influence of the portal vein anatomy.

MATERIAL AND METHODS

On 76 cirrhotic patients (48 men and 28 women) selected for TIPS, rotational, three-dimensional (3D), catheter-directed angiography of the portal vein was performed. The 3D portograms were reviewed by two independent interventional radiologists to determine the optimal angiographic projection views for stent-graft placement. Intra-observer and inter-observer reliabilities were tested and subgroups of patient portal vein anatomy were categorized.

RESULTS

Among all patients, the optimal portal venous projection views for stent-graft placement during TIPS centered around 27° (±14°) right oblique and 3° (±7°) craniocaudal. Of these, 56% were within the standard deviations. Intra-observer reliabilities were 0.60 and 0.62 for the two radiologists, respectively. Inter-observer reliability was 0.48. Anatomical variations in the patient population were: normal portal vein (67%), trifurcation at main portal vein (16%), right posterior portal vein as the first branch of main portal vein (3%), no right posterior portal vein (1%), and other variations (13%). Anatomical subgroups did not influence the best angiographic projection view significantly (F4,295 = 0.91, P = 0.457).

CONCLUSION

The mean optimal angiographic projection view for TIPS stent-graft placement was 27° right oblique and 3° craniocaudal. Patient anatomic variations do not play a significant role in determining the optimal angiographic view for TIPS stent-graft placement.

Patient radiation management and preprocedure planning and consent

Protection of patients from excessive medical radiation has become a high priority in health care. As clinical physicians, interventional radiologists must remain cognizant of the radiation we use in daily practice. Radiation reduction begins before the procedure itself, as with appropriate preprocedural planning the amount of fluoroscopy and angiography used can then be reduced. Patients should be counseled regarding the potential for use of significant amounts of radiation when procedures associated with such doses are planned, as part of the process of obtaining informed consent. If significant radiation is used, patients should be alerted to have appropriate follow-up. The amount of radiation used can be reduced by careful attention to imaging technique.