International consensus on use of focused ultrasound for painful bone metastases: Current status and future directions.

Focused ultrasound surgery (FUS), in particular magnetic resonance guided FUS (MRgFUS), is an emerging non-invasive thermal treatment modality in oncology that has recently proven to be effective for the palliation of metastatic bone pain. A consensus panel of internationally recognised experts in focused ultrasound critically reviewed all available data and developed consensus statements to increase awareness, accelerate the development, acceptance and adoption of FUS as a treatment for painful bone metastases and provide guidance towards broader application in oncology. In this review, evidence-based consensus statements are provided for (1) current treatment goals, (2) current indications, (3) technical considerations, (4) future directions including research priorities, and (5) economic and logistical considerations.

Volumetric MR-guided high-intensity focused ultrasound versus uterine artery embolisation for treatment of symptomatic uterine fibroids: comparison of symptom improvement and reintervention rates.

PURPOSE: To compare the effectiveness of magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) with that of uterine artery embolisation (UAE) for treatment of uterine fibroids. METHODS: Between January 2010 and January 2013, 51 women with symptomatic uterine fibroids underwent MR-HIFU. Follow-up and MR imaging were compared to 68 women treated with UAE, who fulfilled eligibility criteria for MR-HIFU - e.g., size (≤ 12 cm) and number (≤ 5) of fibroids. We compared median symptom severity (tSSS), total health-realted quality of life (HRQoL) scores, and reintervention rates. The adjusted effect on symptom relief and HRQoL improvement was calculated using multivariable linear regression. Cox regression was applied to calculate the adjusted risk of reintervention between both treatments. RESULTS: Median tSSS improved significantly from baseline to three-month follow-up (P < 0.001) for both MR-HIFU (53.1 (IQR [40.6-68.8]) to 34.4 (IQR [21.9-46.9]) and UAE (65.3 (IQR [56.3-74.2]) to 21.9 (IQR [9.4-34.4]). In addition, significantly better HRQoL scores were observed after three months (P < 0.001). However, in multivariate analysis, UAE had a stronger effect on symptom relief and HRQoL improvement than MR-HIFU (P < 0.001). Patients treated with MR-HIFU had a 7.1 (95 % CI [2.00-25.3]; P = 0.002) times higher risk of reintervention within 12 months (18/51 vs. 3/68). CONCLUSION: Both MR-HIFU and UAE result in significant symptom relief related to uterine fibroids. However, MR-HIFU is associated with a higher risk of reintervention. KEY POINTS: • This study compared outcomes between volumetric MR-HIFU and UAE for uterine fibroids. • Both MR-HIFU and UAE result in significant symptom relief and quality of life improvement. • UAE had a stronger positive effect on the clinical outcomes. • Reintervention rate after MR-HIFU ablation was significantly higher than after UAE.

Diffusion-weighted magnetic resonance imaging using different b-value combinations for the evaluation of treatment results after volumetric MR-guided high-intensity focused ultrasound ablation of uterine fibroids.

OBJECTIVES: To assess the value of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficient (ADC) mapping using different b-value combinations for treatment evaluation after magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) of uterine fibroids. METHODS: Fifty-six patients with 67 uterine fibroids were treated with volumetric MR-HIFU. Pre-treatment and post-treatment images were obtained using contrast-enhanced T1-weighted MRI (CE-T1WI) and DWI using b = 0, 200, 400, 600, 800 s/mm(2). ADC maps were generated using subsets of b-values to investigate the effects of tissue ablation on water diffusion and perfusion in fibroids treated with MR-HIFU. Four combinations of b-values were used: (1) all b-values; (2) b = 0, 200 s/mm(2); (3) b = 400, 600, 800 s/mm(2); and (4) b = 0, 800 s/mm(2). RESULTS: Using the lowest b-values (0 and 200 s/mm(2)), the mean ADC value in the ablated tissue reduced significantly (p < 0.001) compared with baseline. Calculating the ADC value with the highest b-values (400, 600, 800 s/mm(2)), the ADC increased significantly (p < 0.001) post-treatment. ADC maps calculated with the lowest b-values resulted in the best visual agreement of non-perfused fibroid tissue detected on CE images. Other b-value combinations and normal myometrium showed no difference in ADC after MR-HIFU treatment. CONCLUSIONS: A decrease in contrast agent uptake within the ablated region on CE-T1WI was correlated to a significantly decreased ADC when b = 0 and 200 s/mm(2) were used. KEY POINTS: DWI could be useful for treatment evaluation after MR-HIFU of uterine fibroids. The ADC in fibroid tissue is influenced by the choice of b- values. Low b-values seem the best choice to emphasise perfusion effects after MR-HIFU.

Is an intrauterine device a contraindication for uterine artery embolization? A study of 20 patients.

The presence of an intrauterine device (IUD) has been traditionally considered a risk factor for postprocedural infection in patients undergoing uterine artery embolization (UAE). The authors retrospectively evaluated the occurrence of infectious complications following embolization in 20 women with IUDs. After a mean follow-up of 20.5 months, none of the patients developed an infectious complication. One patient required hysterectomy following embolization for persistent pain. Pathologic evaluation of the hysterectomy specimen demonstrated ischemia without evidence of inflammation. This experience suggests that the presence of an IUD might not be considered a contraindication for UAE.

Embolization of uterine leiomyomas with polyzene F-coated hydrogel microspheres: initial experience.

PURPOSE: To evaluate effectiveness and safety of Polyzene F-coated hydrogel microspheres for uterine artery embolization (UAE) in women with symptomatic uterine leiomyomas. MATERIALS AND METHODS: Between August 2006 and August 2008, 86 nonconsecutive premenopausal women (mean age, 43.9 years; median, 44 y; range, 28-54 y) were treated with UAE. Calibrated microspheres of 500, 700, and 900 µm, alone or in combination, were used as embolic agents. Change in uterine and tumor volume and tumor infarction rate during follow-up were assessed with magnetic resonance imaging. Clinical follow-up was evaluated by the Uterine Fibroid Severity and Quality Of Life (UFS-QOL) questionnaire at baseline, 3 months, and last follow-up in November 2008. RESULTS: At 3 months, mean volume reductions of the dominant leiomyoma and uterus were 45% and 42%, respectively, and complete infarction of the dominant leiomyoma was achieved in 69 patients (80%). Complete infarction of the overall tumor burden was achieved in 52 patients (60%). Infarction rates of the dominant tumor and overall tumor burden were more than 90% in 81 patients (94%) and 79 patients (91%), respectively. During follow-up, permanent amenorrhea developed in seven women (8.1%). Four women (4.7%) had additional therapy after UAE; three had a hysterectomy and one had a second embolization. The UFS-QOL showed significant improvement in symptom severity and quality of life after 3 months that continued to improve at last follow-up (mean, 12.8 months). CONCLUSIONS: In this preliminary study, Polyzene F-coated hydrogel microspheres for UAE resulted in good dominant and overall tumor infarction in most patients, with corresponding improvement of symptoms. Determining optimal sizing of the material and comparing outcomes versus those of other embolic agents requires additional study.

Safety and effectiveness of uterine artery embolization in patients with pedunculated fibroids.

PURPOSE: To assess complications and outcomes of uterine artery embolization (UAE) in women with pedunculated fibroids in a large single-center patient cohort. MATERIALS AND METHODS: From a database with prospectively collected data from 716 women treated with UAE between 1996 and 2008, 29 women were identified with 31 pedunculated fibroids. Magnetic resonance images obtained before and 3 months after UAE were used to calculate stalk diameter change and volume reduction of both the pedunculated fibroid and uterus. Two observers assessed the overall percentage infarction and infarction of pedunculated fibroid. Complications were recorded and long-term clinical follow-up (mean, 33 months; range, 10-78 months) assessed with use of a questionnaire. RESULTS: The mean reduction in uterine and pedunculated fibroid volume was 37% and 33%, respectively. The mean reduction in stalk diameter was 0.3 cm (95% confidence interval [CI]: 0.18, 0.52 cm) or 13% from initial mean diameter. Stalk enhancement was not affected by UAE. The mean pedunculated fibroid infarction and mean overall infarction rates were 87% and 92%, respectively, for observer 1 and 88% and 92% for observer 2, with good interobserver variability. All women returned the questionnaire and no early or late complications of UAE were reported (0%; 95% CI: 0.0%-13.9%). CONCLUSIONS: In this small series of pedunculated subserosal fibroids treated with UAE, no complications occurred. The findings suggest that the use of UAE to treat pedunculated subserosal fibroids may be safe and effective.

Iatrogenic lumbar pseudoaneurysm causing dural sac compression after spine surgery.

A 69-year-old man presented 3 months after lumbar spine surgery with progressive paraparesis and bladder and sphincter dysfunction caused by a lumbar artery pseudoaneurysm compressing the dural sac. After embolization with glue, the thrombosed pseudoaneurysm substantially decreased in size and the patient's neurological symptoms improved.

Magnetic resonance angiography of collateral blood supply to spinal cord in thoracic and thoracoabdominal aortic aneurysm patients.

OBJECTIVE: Preservation of spinal cord blood supply during descending thoracic (TAA) and thoracoabdominal aortic aneurysm (TAAA) surgery is mandatory to prevent neurologic complications. Although collateral arteries have been identified occasionally and are considered crucial for maintaining spinal cord function in the individual patient, their critical functionality is poorly understood and very little experience exists with visualization. This study investigated whether the preoperative and postoperative presence or absence of collateral arteries detected by magnetic resonance angiography (MRA) is related to spinal cord function during the intraoperative exclusion of the segmental supply to the Adamkiewicz artery. METHODS: Spinal cord MRA was used to localize the Adamkiewicz artery and its segmental supplier in 85 patients scheduled for open elective surgery for TAA or TAAA. The segmental artery to the Adamkiewicz artery was inside the cross-clamped aortic area in 55 patients, and spinal cord supply was consequently dependent on collateral supply. In these 55 patients the presence of collaterals originating from arteries outside the cross-clamped aortic segment was related to changes in the intraoperative motor-evoked potentials (MEPs) that occurred before corrective measures. Twenty-one patients returned for postoperative MRA. RESULTS: A highly significant (P < .0015) relation was found between the presence of collaterals and intraoperative spinal cord function. In 30 of 31 patients (97%) in whom collaterals were identified, MEPs remained stable. The collaterals in most patients originated caudally to the distal clamp (eg, from the pelvic arteries), which were perfused by means of extracorporeal circulation during cross-clamping. The MEPs declined in 9 of 24 patients (38%) in whom no collaterals were preoperatively visualized. Postoperatively, the 21 patients who had MRA, including 10 in whom preoperatively no collaterals were found, displayed a well-developed collateral network. CONCLUSION: Collateral arteries supplying the spinal cord can be systematically visualized using MRA. Spinal cord blood supply during open aortic surgery may crucially depend on collateral arteries. Preoperatively identified collateral supply was 97% predictive for stable intraoperative spinal cord function. Patients in whom no collaterals can be depicted preoperatively are at increased risk for spinal cord dysfunction.

Imaging in spinal vascular disease.

Spinal vascular diseases are rare and constitute only 1% to 2% of all vascular neurologic pathologies. In this article, the following vascular pathologies of the spine are described: spinal arterial infarcts, spinal cavernomas, and arteriovenous malformations (including perimedullary fistulae and glomerular arterivenous malformations), and spinal dural arteriovenous fistulae. This article gives an overview about their imaging features on MRI, MR angiography, and digital subtraction angiography. Clinical differential diagnoses, the neurologic symptomatology, and the potential therapeutic approaches of these diseases, which might vary depending on the underlying pathologic condition, are given.

Uterine Artery Embolization for Symptomatic Adenomyosis: 7-Year Clinical Follow-up Using UFS-Qol Questionnaire.

PURPOSE: The purpose of this study was to assess clinical outcomes 7 years after uterine artery embolization (UAE) in the treatment of symptomatic adenomyosis. MATERIALS AND METHODS: In this prospective cohort study, one specialized hospital in the Netherlands recruited patients with symptomatic adenomyosis or adenomyosis in combination with fibroids for UAE. The 7-year post-intervention outcomes were health-related quality of life (HRQOL), symptom severity scores (SSS), satisfaction, menopause and re-interventions. RESULTS: Twenty-nine patients with adenomyosis (15 with fibroids) were treated with UAE between September 2006 and January 2010. The 7-year questionnaire was mailed in November 2016. The mean follow-up was 95 months (SD 9.0) at a mean age of 50 (SD 5.4). Questionnaires were returned by 24/29 patients (83%). The remaining five patients were contacted through telephone. One of these patients was untraceable. Seven years after treatment 5 of 28 patients (18%) underwent a secondary hysterectomy. The HRQOL and SSS scores as measured by UFS-QOL at 3 months after UAE showed significant improvement of -57 points (score: 15) and +40 points (score: 91), respectively. These scores remained comparable stable up unto 7 years. The SSS showed a significant difference of 17 points (0-100) in favor of the adenomyosis in combination with fibroids group (p = 0.020). Menopause was reported by 10/28 patients (36%). Twenty-one of 29 (72%) patients declared to be at least fairly satisfied about UAE. CONCLUSIONS: After 7 years of follow-up, in 82% of UAE-treated patients with symptomatic adenomyosis a hysterectomy was avoided.

Accuracy of semiautomated analysis of 3D contrast-enhanced magnetic resonance angiography for detection and quantification of aortoiliac stenoses.

OBJECTIVES: We sought to compare reproducibility and accuracy of semiautomated stenosis detection and quantification in 3D contrast-enhanced magnetic resonance angiography (CE-MRA) images with conventional evaluation of 3D CE-MRA in patients with peripheral arterial disease (PAD) by using intra-arterial digital subtraction angiography (IA-DSA) as standard of reference. METHODS: Twenty-five patients with PAD underwent CE-MRA and IA-DSA. Three blinded observers independently evaluated CE-MRA datasets for stenoses in the aortoiliac region using semiautomated computer analysis. Semiautomated measurements were compared with conventional measurements of stenosis on CE-MRA datasets, as measured by 3 other independent observers blinded to all other measurements. Interobserver agreement was quantified using kappa (kappa) and intraclass correlation coefficients (ICCs). Sensitivity and specificity were determined for both semiautomated and conventional measurements. RESULTS: Semiautomated measurements were successful in 124 of the 125 arterial segments. The sensitivity of semiautomated measurements was 89% for all observers; specificity varied between 87% and 89%. For conventional measurements of CE-MRA, sensitivity varied between 79% and 86%; specificity was between 86% and 96%. There was good interobserver agreement between all readers for semiautomated measurements (combined kappa for all 3 observers together = 0.78; ICC = 0.82), as well as for conventional measurements (combined kappa = 0.70; and ICC = 0.83). Differences between ICCs, combined kappa values, and accuracy of both measurements were not significant (all P > 0.05). CONCLUSION: Semiautomated analysis of aortoiliac 3D CE-MRA has the same high accuracy for detection and quantification of stenoses as conventional readings of CE-MRA.

Quality of MR thermometry during palliative MR-guided high-intensity focused ultrasound (MR-HIFU) treatment of bone metastases.

BACKGROUND: Magnetic resonance (MR)-guided high-intensity focused ultrasound has emerged as a clinical option for palliative treatment of painful bone metastases, with MR thermometry (MRT) used for treatment monitoring. In this study, the general image quality of the MRT was assessed in terms of signal-to-noise ratio (SNR) and apparent temperature variation. Also, MRT artifacts were scored for their occurrence and hampering of the treatment monitoring. METHODS: Analyses were performed on 224 MRT datasets retrieved from 13 treatments. The SNR was measured per voxel over time in magnitude images, in the target lesion and surrounding muscle, and was averaged per treatment. The standard deviation over time of the measured temperature per voxel in MRT images, in the muscle outside the heated region, was defined as the apparent temperature variation and was averaged per treatment. The scored MRT artifacts originated from the following sources: respiratory and non-respiratory time-varying field inhomogeneities, arterial ghosting, and patient motion by muscle contraction and by gross body movement. Distinction was made between lesion type, location, and procedural sedation and analgesic (PSA). RESULTS: The average SNR was highest in and around osteolytic lesions (21 in lesions, 27 in surrounding muscle, n = 4) and lowest in the upper body (9 in lesions, 16 in surrounding muscle, n = 4). The average apparent temperature variation was lowest in osteolytic lesions (1.2°C, n = 4) and the highest in the upper body (1.7°C, n = 4). Respiratory time-varying field inhomogeneity MRT artifacts occurred in 85% of the datasets and hampered treatment monitoring in 81%. Non-respiratory time-varying field inhomogeneities and arterial ghosting MRT artifacts were most frequent (94% and 95%) but occurred only locally. Patient motion artifacts were highly variable and occurred less in treatments of osteolytic lesions and using propofol and esketamine as PSA. CONCLUSIONS: In this study, the general image quality of MRT was observed to be higher in osteolytic lesions and lower in the upper body. Respiratory time-varying field inhomogeneity was the most prominent MRT artifact. Patient motion occurrence varied between treatments and seemed to be related to lesion type and type of PSA. Clinicians should be aware of these observed characteristics when interpreting MRT images.

Volumetric MR-Guided High-Intensity Focused Ultrasound with Direct Skin Cooling for the Treatment of Symptomatic Uterine Fibroids: Proof-of-Concept Study.

OBJECTIVE: To prospectively assess the safety and technical feasibility of volumetric magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation with direct skin cooling (DISC) during treatment of uterine fibroids. METHODS: In this proof-of-concept study, eight patients were consecutively selected for clinical MR-HIFU ablation of uterine fibroids with the use of an additional DISC device to maintain a constant temperature (T ≈ 20 °C) at the interface between the HIFU table top and the skin. Technical feasibility was verified by successful completion of MR-HIFU ablation. Contrast-enhanced T1-weighted MRI was used to measure the treatment effect (nonperfused volume (NPV) ratio). Safety was evaluated by recording of adverse events (AEs) within 30 days' follow-up. RESULTS: All MR-HIFU treatments were successfully completed in an outpatient setting. The median NPV ratio was 0.56 (IQR [0.27-0.72]). Immediately after treatment, two patients experienced coldness related discomfort which resolved at the same day. No serious (device-related) AEs were reported. Specifically, no skin burns, cold injuries, or subcutaneous edema were observed. CONCLUSION: This study showed that it is safe and technically feasible to complete a volumetric MR-HIFU ablation with DISC. This technique may reduce the risk of thermal injury to the abdominal wall during MR-HIFU ablation of uterine fibroids. This trial is registered with NTR4189.

Non-invasive magnetic resonance-guided high intensity focused ultrasound ablation of a vascular malformation in the lower extremity: a case report.

INTRODUCTION: Therapy of choice for symptomatic vascular malformations consists of surgery, sclerotherapy, or embolization. However, these techniques are invasive with possible complications and require hospitalization. We present a novel non-invasive technique, i.e., magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation, for the treatment of a vascular malformation in a patient. This technique applies high-intensity sound waves transcutaneously to the body and is fully non-invasive. MRI guidance is the novel aspect of HIFU treatments and is used for exquisite delineation and localization of the lesion and accurate real-time temperature monitoring during tissue ablation. MR-HIFU is a well-established treatment option for uterine fibroids and is currently being investigated for, e.g., bone tumors, breast cancer, prostate cancer, and liver cancer. MR-HIFU of vascular malformations has not been a topic of research yet. CASE DESCRIPTION: Volumetric MR-HIFU ablation of a vascular malformation in the lower extremity of an 18-year-old male patient was performed. Temperatures of 62-80 °C were reached in the target lesion with sonications of 4 × 4 × 8 mm using powers of 200 W for <20 s. At 1-month follow-up, the patient reported qualitatively sustained reduction of pain and normal motor function. Three-month follow-up imaging indicated successful nidus destruction, which resulted in reduction of >30 % of the tumor volume. After 13 months, pain score was reduced to <2 after extreme exertion for several hours and to 0 for daily activities. DISCUSSION AND EVALUATION: Radiofrequency ablation and cryoablation are minimally invasive techniques that have been tried on low-flow vascular malformations with inconsistent results. Furthermore, both techniques require probe insertion, which is associated with risks of wound infection and hospitalization. Since MR-HIFU is truly non-invasive, these risks are negligible. CONCLUSIONS: In conclusion, we reported a successful non-invasive treatment of a vascular malformation with MR-HIFU in a clinical patient including long-term follow-up data for the first time. The patient reported qualitatively sustained pain reduction up to 13 months post treatment.

Registration of CT to pre-treatment MRI for planning of MR-HIFU ablation treatment of painful bone metastases.

MR-HIFU is a new non-invasive treatment modality that can be used for palliation in patients with painful bone metastases. Since treatment strategies are mainly focused on the ablation of periosteal nerves, information on the presence and geometry of cortical bone influences the treatment strategy, both in determining the acoustic power and in avoiding safety issues related to far-field heating. Although MRI is available for imaging during treatment, CT is best used for examining the cortical bone. We present a registration method for registering CT and MR images of patients with bone metastases prior to therapy. CT and MRI data were obtained from nine patients with metastatic bone lesions at varying locations. A two-step registration approach was used, performing simultaneous rigid registration of all available MR images in the first step and an affine and deformable registration with an additional bone metric in the second step. The performance was evaluated using landmark annotation by clinical observers. An average registration error of 4.5 mm was obtained, which was comparable to the slice thickness of the data. The performance of the registration algorithm was satisfactory, even with differences in MRI acquisition parameters and for various anatomical sites. The obtained CT overlay is useful for treatment planning, as it allows an assessment of the integrity of the cortical bone. CT-MR registration is therefore recommended for HIFU treatment planning of patients with bone metastases.

Feasibility of volumetric MRI-guided high intensity focused ultrasound (MR-HIFU) for painful bone metastases.

BACKGROUND: Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) has recently emerged as an effective treatment option for painful bone metastases. We describe here the first experience with volumetric MR-HIFU for palliative treatment of painful bone metastases and evaluate the technique on three levels: technical feasibility, safety, and initial effectiveness. METHODS: In this observational cohort study, 11 consecutive patients (7 male and 4 female; median age, 60 years; age range, 53-86 years) underwent 13 treatments for 12 bone metastases. All patients exhibited persistent metastatic bone pain refractory to the standard of care. Patients were asked to rate their worst pain on an 11-point pain scale before treatment, 3 days after treatment, and 1 month after treatment. Complications were monitored. All data were prospectively recorded in the context of routine clinical care. Response was defined as a ≥2-point decrease in pain at the treated site without increase in analgesic intake. Baseline pain scores were compared to pain scores at 3 days and 1 month using the Wilcoxon signed-rank test. For reporting, the STROBE guidelines were followed. RESULTS: No treatment-related major adverse events were observed. At 3 days after volumetric MR-HIFU ablation, pain scores decreased significantly (p = 0.045) and response was observed in a 6/11 (55%) patients. At 1-month follow-up, which was available for nine patients, pain scores decreased significantly compared to baseline (p = 0.028) and 6/9 patients obtained pain response (overall response rate 67% (95% confidence interval (CI) 35%-88%)). CONCLUSIONS: This is the first study reporting on the volumetric MR-HIFU ablation for painful bone metastases. No major treatment-related adverse events were observed during follow-up. The results of our study showed that volumetric MR-HIFU ablation for painful bone metastases is technically feasible and can induce pain relief in patients with metastatic bone pain refractory to the standard of care. Future research should be aimed at standardization of the treatment procedures and treatment of larger numbers of patients to assess treatment effectiveness and comparison to the standard of care.

Uterine artery embolization in patients with a large fibroid burden: long-term clinical and MR follow-up.

Uterine artery embolization (UAE) in patients with a large fibroid burden is controversial. Anecdotal reports describe serious complications and limited clinical results. We report the long-term clinical and magnetic resonance (MR) results in a large series of women with a dominant fibroid of >10 cm and/or an uterine volume of >700 cm(3). Seventy-one consecutive patients (mean age, 42.5 years; median, 40 years; range, 25-52 years) with a large fibroid burden were treated by UAE between August 2000 and April 2005. Volume reduction and infarction rate of dominant fibroid and uterus were assessed by comparing the baseline and latest follow-up MRIs. Patients were clinically followed at various time intervals after UAE with standardized questionnaires. There were no serious complications of UAE. During a mean follow-up of 48 months (median, 59 months; range, 6-106 months), 10 of 71 patients (14%) had a hysterectomy. Mean volume reduction of the fibroid and uterus was 44 and 43%. Mean infarction rate of the fibroid and overall fibroid infarction rate was 86 and 87%. In the vast majority of patients there was a substantial improvement of symptoms. Clinical results were similar in patients with a dominant fibroid >10 cm and in patients with large uterine volumes by diffuse fibroid disease. In conclusion, our results indicate that the risk of serious complications after UAE in patients with a large fibroid burden is not increased. Moreover, clinical long-term results are as good as in other patients who are treated with UAE. Therefore, a large fibroid burden should not be considered a contraindication for UAE.

Differentiation of spinal cord arteries and veins by time-resolved MR angiography.

PURPOSE: To dynamically resolve the inlet arteries and outlet veins of the spinal cord, particularly the Adamkiewicz artery (AKA) and great anterior radiculomedullary vein (GARV), using MR angiography (MRA). MATERIALS AND METHODS: First, conventional two-phase angiography (acquisition time = 38-55 seconds) utilizing elliptic centric k-space ordering was applied to aortic-aneurysm patients. Changes of vessel intensity were compared between two subsequent dynamic phases. Computer modeling of bolus enhancement and k-space sampling was performed to demonstrate the relation between vessel enhancement, acquisition time, and vessel diameter. Second, time-resolved (TR, or "keyhole") angiography using a reduced number of phase-encoding steps was explored in healthy volunteers and aortic-aneurysm patients using acquisition times (range = 6-8.5 seconds) shorter than the spinal cord circulation time. RESULTS: Using two-phase angiography the AKA and GARV were covisualized in the early phase, and contrast decreased for the AKA and increased for the GARV in most (70%) but not all cases. Computer modeling showed that the arteriovenous contrast strongly depended on vessel diameter, and complete separation was only obtained with short acquisition times. Using TR MR angiography (TR-MRA), complete temporal separation of the AKA and GARV was realized in all cases (100%). CONCLUSION: The AKA and GARV can be completely separated by TR-MRA.

Magnetic resonance angiography and neuromonitoring to assess spinal cord blood supply in thoracic and thoracoabdominal aortic aneurysm surgery.

OBJECTIVE: Preoperative knowledge of the blood-supplying trajectory to the spinal cord is of interest, because spinal cord ischemia may occur during thoracic aortic aneurysm (TAA) and thoracoabdominal aortic aneurysm (TAAA) repair and possibly leads to paraplegia. The Adamkiewicz artery (AKA) is considered to be the most important blood supplier of the thoracolumbar spinal cord and has therefore been the focus in preoperative diagnostic imaging. However, in TAA(A) patients, the blood supply to the spinal cord may strongly depend on (intersegmental) collateral circulation, because many segmental arteries are occluded as a result of atherosclerosis. Therefore, the importance of preserving the segmental artery supplying the AKA (SA-AKA) is debated. Here it was investigated whether (1) the AKA and its segmental supplier can be imaged by using magnetic resonance (MR) angiography and (2) aortic cross-clamping of the SA-AKA influences intraoperative spinal cord function, monitored by motor evoked potentials (MEPs). METHODS: Preoperative MR angiography was performed to localize the SA-AKA and the AKA in 60 patients (19 TAA, 7 TAAA I, 18 TAAA II, 9 TAAA III, and 7 TAAA IV). Spinal cord function was monitored during surgery by using MEPs. When MEPs indicated critical ischemia, the SA-AKA was selectively reattached. To test whether aortic cross-clamping of the SA-AKA was associated with MEP decline, the Fisher statistical exactness test was applied. RESULTS: The AKA and SA-AKA could be localized in all 60 (100%) patients between vertebral levels T8 and L2 (72% left sided). In 44 (73%) patients, the SA-AKA was cross-clamped, which led in 32% (14/44) of cases to MEP decline. Reattachment of the preoperatively localized SA-AKA re-established MEPs and, thus, spinal cord function in 12 of 14 cases. When the SA-AKA was outside the area cross-clamped, the MEPs always remained stable. A significant association (P < .01) was found between the location of the SA-AKA relative to the aortic cross-clamps and the MEPs. CONCLUSIONS: The AKA can be localized before surgery in 100% of TAA(A) patients by using MR angiography. Location of the SA-AKA outside the cross-clamped aortic area is attended with stable MEPs. Interestingly, it was found that in most patients in whom the SA-AKA was cross-clamped, MEPs were not affected, thus indicating sufficient collateral blood supply to maintain spinal cord integrity. Nevertheless, preoperative knowledge of SA-AKA location is of importance, because in 32% of patients, spinal cord function was dependent on this supplier. Revascularization of the SA-AKA can thereby reverse spinal cord dysfunction.