3.0T MR快速导引自动实时跟踪经直肠行前列腺穿刺活检的可行性研究

目的评估3.0 T MR基于实时纯相位交叉相关(POCC)算法序列进行自动跟踪导引经直肠行前列腺穿刺活检的可行性。材料与方法本研究通过伦理审查委员会批     

MR兼容辅助穿刺系统在高场强MR引导下前列腺可疑病变穿刺活检的初步结果

目的评价MR兼容机器人穿刺系统在1.5T高场强MR引导下经臀部途径对前列腺可疑病变穿刺活检的可行性和安全性。材料与方法研究通过法兰克福大学机构审查委员会批准,并且获得了每例病人的知情同意。共20例病     

欧洲泌尿生殖放射学会PI-RADS评分系统在3.0T多参数前列腺MR成像中的应用价值:联合靶向MR/经直肠超声引导下前列腺活检

正目的旨在评估欧洲泌尿生殖放射学会(ESUR)制定的前列腺影像报告和数据系统(PI-RADS)在前列腺癌(PCa)多参数MR成像(mpMRI)检测中的应用价值,本研究     

不可切除性肝细胞癌经肝动脉化疗栓塞后早期血管和细胞变化的MR监测

目的 在有细胞学和组织病理学结果的前提下,回顾性分析成功进行超声引导下肝脏局灶性病灶穿刺活检的影响因素。方法 机构审查委员会豁免此项符合HIPAA法案的回顾性研究。收集2000年1月—2006年2月间在同一结构进行经皮超声引导下肝脏局灶性病灶穿刺活检并有细胞学和组织病理学结果的病例。     

在短、宽口径,1.5T系统中的全身增强MR血管成像:Gd-BOPTA和Gd-DOTA的个体对照

全身增强磁共振血管成像(CE-MRA)一站式扫描能够提供全部循环系统的信息。短、宽口径扫描仪可能因Z轴视野受限而还未能应用于全身CE-MRA。本可     

1．5T和3T上钆贝酸二葡甲胺心肌延迟增强MRI的个体间对比

对比增强成像技术依赖于T1的加权力度,因此与1．5T相比．3T能提供更高的对比度。本研究的目的是观察延迟增强MRI在1．5T和3T上个体间的差别。20例心肌梗死的病人分别用1．5T和3T行MRI检查。注射对比剂后15min（0．1mmol／kg体质量钆喷酸二甲葡胺）行反转恢复梯度回波序列（IR-GRE）检查（1．5T／3T：TR11．0／9．9ms,TE4．4／4．9ms,翻转角度30°／30°,层厚6／6mm）来评价心肌活性。2位观察者评定影像质量（Wilcoxon标记的秩和检验）。     

基于全肝T_(1ρ)MR影像评估肝脏纤维性疾病:在1.5T上的可行性研究

正目的测试在1.5 T场强下,T1ρMR影像评价肝脏纤维性疾病的可行性,研究肝脏T1ρMR影像是否能够评估肝硬化的严重性,评估健康病人正常的肝脏T1ρ范围。材料与方     

在3.0T上采用传统单源射频发射与双源平行射频发射T2WI对肝脏局灶性病灶的显示及影像质量的比较

目的前瞻性对3.0TMRT2加权单次激发快速自旋回波序列(TSE)采用双源平行射频发射与传统单源射频发射在肝脏局灶病变的检出率、影像质量、病灶显著程度和病     

MR-guided liver biopsy within a short, wide-bore 1.5 Tesla MR system

The purpose of this study was to evaluate the diagnostic efficacy of magnetic resonance (MR)-guided biopsy of focal liver lesions within a short, wide-bore 1.5-T MR system and to determine the duration and accuracy of needle placement using MR fluoroscopy guidance in 25 patients. Accuracy of needle placement was evaluated in two orthogonal planes, and the out-of-plane angle of needle deflection was measured. Needle positioning was characterised subjectively as centred, peripheral, or exterior relative to the lesion. Exterior positioning was corrected by a step-by-step procedure. Surgical resection (n = 6), previous histologies (n = 8), or clinical/radiological follow-up (n = 11) served as the ‘gold standard’. The guidance needle could be placed successfully using MR fluoroscopy in 20 of 25 patients (80%). Needle placement was rated as ‘centred’ in 11 and as ‘peripheral’ in nine patients. Median needle deflection was 2.6 degrees, with a median deviation of 3.4 mm. In five patients, the direct approach failed or was rated as ‘exterior’; therefore, repositioning after needle stabilisation with a stainless-steel stylet was necessary. The diagnostic yield of all biopsies was: sensitivity 95.5%, specificity 100.0% and accuracy 96.0%. In conclusion, MR-guided biopsies in a short, wide-bore MR system yielded highly reliable biopsy results, and in most cases the direct approach with MR fluoroscopy guidance proved to be fast and accurate.     

MR-guided core biopsy with MR fluoroscopy using a short, wide-bore 1.5-Tesla scanner: feasibility and initial results

PURPOSE: To evaluate MR fluoroscopy in a short, wide-bore 1.5T MRI suitable for near real-time biopsy guidance. MATERIALS AND METHODS: A total of eight consecutive patients underwent MR-guided core biopsy in a 1.5T system with a 70 cm bore diameter. A total of five biopsies were performed in focal liver lesions, three biopsies in soft-tissue tumors. Before biopsy, three different fast MR sequences were compared for image quality (anatomical visibility, lesion visibility, and artifacts), and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. In all cases, an MR-compatible guidance needle was positioned under MR fluoroscopy using the most suitable sequence. RESULTS: In each patient the guidance needle could be placed accurately under MR fluoroscopy without having to remove the patient from the isocenter of the magnet during needle movement. All biopsies were technically successful and appropriate specimens could be obtained. In prebiopsy imaging, a T2-weighted single shot turbo spinecho sequence (half-Fourier acquisition single-shot turbo spin-echo [HASTE]) achieved the best rating for lesion visibility and superior SNR and CNR values. CONCLUSION: Findings of this study demonstrate that MR fluoroscopy for biopsy guidance in a short, wide-bore 1.5T scanner is feasible. This scanner combines the patient access advantages of an open-bore system with the superior image quality and speed of a high-field scanner. In our series, the HASTE sequence was best suited for MR-guidance of biopsies.     

1.0T开放式MR引导下椎间盘成像

目的评价1.0T开放式MR引导下椎间盘成像的可行性。方法计划施行椎间盘热治疗术、椎间盘置换术或椎体融合术的41例病人的48个椎间盘作为本次研究的对象,1.0T开放式MR作为椎间盘成像的引导和成像工具。采用自旋回波序列质子加权扫描(PDWTSE)引导椎间盘穿刺,穿刺     

MR-guided discography using an open 1 Tesla MRI system

Objective  

To evaluate the feasibility of MR-guided discography using an open 1 Tesla MRI system.     

213例使用宽口径1.5TMR设备引导下射频消融治疗肝脏病变

目的探讨使用宽口径1.5TMR设备引导下射频消融(RF)治疗肝脏恶性肿瘤的有效性、成功性和安全性。方法在110例病人中,56个原发性肝癌病变和157个肝转移病变接受了157次经皮射频消融治疗。平均病灶直径为20mm(4～54mm)。所有的治疗计划、程序和介入治疗后监测均在宽口径1.5TMR设备下进行。介入治疗后立即行肝脏MR增强扫描检查对技术的成功性进行评估。通过肝脏的动态MR成像,对消融技术治疗1个月后的有效性进行了研究评估,平均随访时间为24.2个月(范围5～44个月)。结果 210/213个病变(98.6%)达到技术成功和技术有效。18/210病变(8.6%)治疗4～28个月后发生肿瘤局部复发浸润。18个病变中的7个取得二次完全消融治疗,其他6例病变行手术治疗。总体射频消融(RF)有效率为93.4%(199/213),整体治疗成功率(包括手术)为96.2%(205/213)。发生2种严重并发症(1.3%)(出血和感染性胆汁瘤)和14种(8.9%)轻微并发症,其中有157个病变接受了干预措施。结论宽口径MR引导下射频消融治疗肝脏病变是一种安全、有效的治疗方法。     

MR-guided radiofrequency ablation using a wide-bore 1.5-T MR system: clinical results of 213 treated liver lesions

Objective

To evaluate the technical effectiveness, technical success and patient safety of MR-guided radiofrequency (RF) ablation of liver malignancies using a wide-bore 1.5-T MR system.

Methods

In 110 patients, 56 primary liver lesions and 157 liver metastases were treated in 157 sessions using percutaneous RF ablation. Mean lesion diameter was 20?mm (range 4–54?mm). All planning, procedural and post-interventional control MR investigations were carried out using a wide-bore 1.5-T MR system. Technical success was assessed by a contrast-enhanced MR liver examination immediately after the intervention. Technique effectiveness was assessed by dynamic hepatic MR study 1?month post ablation; mean follow-up period was 24.2?months (range 5–44).

Results

Technical success and technique effectiveness were achieved in 210/213 lesions (98.6?%). In 18/210 lesions (8.6?%), local tumour progression occurred 4–28?months after therapy. Seven of these 18 lesions were treated in a second session achieving complete ablation, 6 other lesions were referred to surgery. Overall RF effectiveness rate was 199/213 (93.4?%); overall therapy success (including surgery) was 205/213 (96.2?%). Two major complications (1.3?%) (bleeding and infected biloma) and 14 (8.9?%) minor complications occurred subsequent to 157 interventions.

Conclusion

Wide-bore MR-guided RF ablation is a safe and effective treatment option for liver lesions.

Key Points

? Magnetic resonance-guided radiofrequency ablation offers various options for monitoring therapy. ? All steps of RF ablation carried out in 1.5-T wide-bore system. ? Therapeutic decisions were based on T1-weighted imaging. ? Technical success and technical effectiveness were high. ? Local tumour progression rate was 8.6?% over a 24-month mean follow-up.     

MR-guided biopsy of musculoskeletal lesions in a low-field system

Thirty magnetic resonance (MR)-guided biopsies were obtained from 20 skeletal and 10 soft-tissue lesions in 31 patients using an open 0.2 T MR system equipped with interventional accessories. The results from aspiration (N = 3), core biopsy (N = 15), and transcortical trephine biopsy (N = 12) were evaluated for accuracy and clinical efficacy. Specimens were successfully obtained from 29 patients. Results were clinically effective in 23 patients, rated definitive in 16, nonconclusive in 9, and unspecific in 2 patients. A false diagnosis due to sampling error occurred in 2 patients, and biopsy sampling was impossible in one case. The best diagnostic yield was achieved from nontranscortical biopsies of osteolytic or soft-tissue masses. Results from transcortical biopsies were less specific due to the predominance of benign lesions. MR fluoroscopy for needle guidance was applied in 13 patients. Complete needle placement inside the magnet could be performed in 16 patients. MR-guided biopsy using an open low-field MR imager is feasible and clinically effective and will become a valuable tool in the management of musculoskeletal lesions. J. Magn. Reson. Imaging 2001;13:761-768.     

Total-body contrast-enhanced MRA on a short,wide-bore 1.5-T system: intra-individual comparison of Gd-BOPTA and Gd-DOTA

Total-body contrast-enhanced MRA (CE-MRA) provides information of the entire vascular system according to a one-stop-shop approach. Short, wide-bore scanners have not yet been used for total-body CE-MRA, probably due to their restricted field of view in the z-direction. The purpose of this feasibility study is to introduce an image protocol for total-body MRA on a short, wide-bore system. The protocol includes five to six table-moving steps and two injection runs. Two pharmacologically different contrast materials (CM) were applied in ten healthy volunteers in view of possible CM-dependent influences on the protocol outcome (Gd-Bopta, Gd-Dota). Differences consisted of significantly higher CNR with Gd-Bopta with a mean of 73.8 +/- 38.7 versus 69.1 +/- 34.3 (p = 0.008), significantly better arterial visualization values with Gd-Dota with a mean of 1.26 +/- 0.44 versus 1.53 +/- 0.73 (p = 0.003) and a tendency to less venous overlay with Gd-Dota, mean 1.19 +/- 0.44 and 1.34 +/- 0.72, respectively (p = 0.065) (two-tailed Wilcoxon matched-pairs test). Overall 94% of the steps were valued as qualitatively excellent or good. The good results with both CM suggest a transfer to further patient evaluation.