Value of MRI performed with phased-array coil in the diagnosis and pre-operative classification of perianal and anal fistulas

PURPOSE: To assess the value of MRI performed with phased-array coil in the diagnosis and preoperative staging of perianal and anal fistulas. MATERIALS AND METHODS: 20 patients (13 with Crohn's disease) with clinical evidence or suspicion of anal fistulas underwent pelvic MRI (1.5 T) performed with phased-array coil. Images were obtained in the axial and coronal planes using TSE T2-weighted high resolution sequences with and without fat suppression, T2-weighted HASTE and T1-weighted FLASH sequences, with and without fat suppression, before and after gadolinium enhancement. The following parameters were considered: presence of a fistula and relation with the sphincters, and presence of abscesses or complications. All patients underwent surgery. The MRI and surgical findings were assessed using the Park's fistula-in-ano classification and the St. James MR imaging classification of perianal fistulas. Surgery was considered the gold standard. RESULTS: MRI documented no evidence of fistula in 2 patients, intersphinteric fistulas in 5 (grade 1 and 2 St. James), trans-sphincteric fistulas in 9 (grade 3 and 4 St. James), translevator in 2 (grade 5) and complex ano-rectum-vaginal fistulas in 2. Concordance with surgery was 90%. CONCLUSIONS: MRI is an accurate technique for the identification and classification of anal and perianal fistulas and their complications. In our experience the phased-array coil offers both high field of view and spatial resolution, enabling the demonstration of perianal pathology.     

3.0T高分辨率磁共振成像在肛瘘诊断及分型中的应用

目的探讨3.0T高分辨MRI在肛瘘术前诊断及分型的应用价值。方法选取经手术证实的51例肛瘘患者的临床资料及MRI表现,并与手术结果对照分析,总结肛瘘的MRI表现特点及应用价值。结果51例肛瘘手术显示内口56个,外口43个,主瘘管51条、瘘管分支14条,脓肿16个。与手术结果对照,术前MRI显示肛瘘内、外口、主瘘管及支管的准确率分别为94.64%(53/56个)、100%(43/43个)、94.12%(48/51条)及85.71%(12/14条),对脓肿显示的准确率为100%(16/16个)。按照Parks分型,51例患者MRI共检出括约肌间型肛瘘23例(45.10%),经括约肌型肛瘘17例(33.33%),括约肌上型肛瘘7例(13.73%),括约肌外型肛瘘4例(7.84%),MRI分型准确率为96.08%(49/51例)。MRI在肛瘘Parks分型上与手术结果一致性高,差异无统计学意义(P>0.05)。结论MRI能准确显示肛瘘内、外口的位置,瘘管的数量及走行,能够对肛瘘进行准确分型。     

肛瘘磁共振成像:探讨自制可调节肛肠水囊在肛瘘分级中的价值

目的:探讨普通MR成像中使用自制可调节肛肠水囊在肛瘘患者分级中的应用价值.方法:18例经手术证实的肛瘘患者于使用自制可调节肛肠水囊前、后均各行一次MRI检查.序列包括T_1 WI横断位和冠状位、T_2 W SPAIR横断位,冠状位及矢状位.放置水囊前后比较瘘管末端位置,并且对瘘管、内口、分支及脓腔进行计数,同时观察瘘管走行.所获结果被用于评估肛瘘MR诊断分级,并同时与手术结果相对照.结果:18名肛瘘患者MRI检查共发现瘘管31根、内口22个、分支19根以及脓腔10个.使用水囊前后MRI对瘘管末端位置的显示有显著不同(χ~2=5.56,P<0.05).使用水囊前,MR显示1例1级低位单纯线形括约肌内肛瘘,1例低位和2例高位2级括约肌内肛瘘伴脓肿或分支,1例3级高位经括约肌肛瘘,6例4级经括约肌肛瘘伴脓肿或分支,其中5例为高位,1例为低位,2例5级高位肛提肌上和经肛提肌肛瘘,另有5例无法确定;使用水囊后,2级高位括约肌内肛瘘伴脓肿或分支上升为3例,4级低位经括约肌肛瘘伴脓肿或分支上升至2例,高位上升至7例,另有1例无法确定,余小变.使用水囊前后,M RI对肛瘘分级与手术的相符率分别为72%(13例)和94%(17例).结论:通过使用自制町凋节肛肠水囊,普通M RI能够获得更多有关瘘管及其走行的信息,有助于肛瘘患者的分级.     

磁共振成像对肛瘘分级的价值

目的探讨磁共振成像（MRI）对肛瘘分级价值。方法经手术证实的肛瘘患者26例,全部行MRI检查,检查序列主要包括轴面T1WI、T2WI和轴面、冠状面抑脂T2WI序列。结果 26例肛瘘中,Ⅰ级10例,Ⅱ级6例,Ⅲ级5例,Ⅳ级3例,Ⅴ级2例。MRI诊断26例肛瘘中共有28个瘘管,26个内口,31个外口,14个脓肿,敏感度分别达93%、93%、97%、100%。结论 MRI可以对肛瘘准确分级,对正确的手术治疗非常重要。     

质子加权预饱和脂肪抑制序列在肛瘘中的应用价值

目的评价质子加权预饱和脂肪抑制序列(PDW PFS)对肛瘘显示的准确性及图像质量的清晰性,探讨PDW PFS在肛瘘中的应用价值。资料与方法 20例经手术证实的肛瘘患者术前进行MRI检查,序列包括T1WI、T2W频谱选择性衰减反转恢复序列(SPAIR)和PDW PFS。MRI检查前均向患者肛管直肠内置入肛肠水囊以撑开肛管和直肠。获得图像后,观察患者的瘘管、内口和肛周脓肿,评估和比较MRI各序列显示的瘘管、内口、脓腔,并对PDW PFS和T2W SPAIR序列瘘管的信号强度(SI)、信噪比(SNR)及瘘管与周围肌肉的对比噪声比(CNR)进行测量及比较。结果 PDW PFS序列显示瘘管(100%)、内口(95.7%)、肛周脓肿(100%)的准确率较T1WI及T2WSPAIR序列为高。Kruskal Wallis检验显示上述各序列对瘘管(χ2=6.95,P<0.05)及内口(χ2=31.53,P<0.05)的显示具有显著统计学差异,PDW PFS序列显示瘘管及内口最多。PDW PFS序列SI、SNR值和CNR值均显著高于T2W SPAIR序列(P<0.05)。结论 PDW PFS成像技术具有较高的图像SNR和CNR,更易认识辨别瘘管和内口,可以作为一种新的无创性磁共振成像技术应用于肛瘘成像。     

Image-guided surgery for anal fistula in a 0.5T interventional MRI unit

PURPOSE: To determine whether MR-guided anorectal surgery is feasible, and to develop techniques for MR-guided anal fistula surgery. MATERIALS AND METHODS: Six patients with pilonidal sinus (PNS), and 21 with suspected anal fistulae were operated on in the GE Signa SPIO 0.5T interventional MRI unit. Procedures were performed with magnet-safe Lockhart-Mummery fistula probes. Preprocedural and intra-operative MRI (IOMRI) techniques were used to identify the extent of the fistula tracts and septic foci, and to ensure the adequacy of the surgical procedure. RESULTS: IOMRI demonstrated the PNS lesions and the adequacy of excision. Imaging failed to demonstrate a fistula in two patients, as confirmed by surgical examination. No images were obtained in one patient due to his size (weight in excess of 100 kg). In 18 patients a fistula tract or abscess was demonstrated and IOMRI was used to assess the adequacy of the surgical procedure. In three patients this demonstrated incomplete drainage of septic foci, which was not obvious on inspection of the surgical field. We believe that in these patients IOMRI prevented an incomplete procedure and the potential requirement for a second operation. Further surgery was performed to rectify this situation. The fistula tract was laid open in 13 patients, and a Seton drain was inserted in five. CONCLUSION: MRI-guided surgery for anal fistula is feasible. IOMRI demonstrates the exact anatomy of the tracts and abscesses, and confirms that all have been adequately treated. We believe it may become particularly useful in surgery for recurrent and complex anal fistulae, and may lead to fewer recurrences.     

DWI联合常规MR扫描对肛瘘的诊断价值

目的:评价DWI联合常规MR扫描对肛瘘的诊断价值.方法:选取20例临床怀疑肛瘘或有肛瘘手术史患者行常规MR扫描及DWI检查,比较肛瘘内、外瘘口,瘘管分支及脓肿的显示率.结果:常规MR扫描序列共显示瘘管22个、内口14个、外口22个、脓肿14个;DWI检查共显示瘘管25个、内口16个、外口23个、脓肿17个.结论:DWI...     

肛瘘的术前MRI表现与手术结果的对照分析

目的 探讨术前MRI检查对肛瘘诊断及分型的价值.方法 回顾性分析经手术证实的36例肛瘘患者的临床资料及MRI表现,并与手术结果对照分析,总结肛瘘的MRI表现特点及应用价值.结果 36例肛瘘手术显示内口42个,主瘘管45条、瘘管分支15条,外口42个,脓肿16个.与手术结果对照,MRI显示肛瘘内口的准确率为90.5%(38/42个),显示瘘管分支的准确率为80%(12/15条),显示主瘘管、外口及脓肿的准确率均为100%.按照Parks分型,MRI分型符合率为88.9%(32/36例).结论 MRI能准确显示肛瘘内、外口的位置,瘘管的数量及走行,能够对肛瘘进行准确分型.     

Endoanal MRI of perianal fistulas: the optimal imaging planes

Twenty consecutive patients with the clinical suspicion of a perianal fistula were studied to define the optimal and time-efficient imaging planes for endoanal MRI in the identification and classification of perianal fistulas. The duration of each part of the MR procedure was recorded in all patients. Off-axis axial (A), coronal (C), sagittal (S) and radial (R) T2-weighted sequences were performed in all patients. Sets of images and combinations of images (A; R; CS; AR; ACS; ARCS) without patient data were reviewed in masked fashion and independently with a 2-month interval between each set. The reader was masked to the results of previous readings. The findings were compared with the surgical findings. The number of correctly identified and classified fistula and the sensitivity and specificity were determined. Twenty fistulas were present at surgery: 14 transsphincteric fistulas and six intersphincteric fistulas. Eighteen fistulas were correctly identified with the radial (R) and combined coronal sagittal (CS) sequences. In all other sequences or combinations of sequences all 20 fistulas were identified. Classification was correct with A in 16 patients, with R in 15, with CS in 15, with AR in 18, with ACS in 17 and with ARCS in 18. The sensitivity and specificity were optimal using AR or ARCS (0.86 and 1 respectively). The optimal and most time-efficient imaging protocol for endoanal MRI of perianal fistulas thus comprises the axial and radial imaging planes. Received 29 September 1997; Revision received 13 February 1998; Accepted 17 March 1998     

Magnetic Resonance Imaging Evaluation of Perianal Fistulas

Purpose

The purpose of this study was to discuss the usefulness of magnetic resonance imaging in evaluating perianal fistulas, their ramifications, extent, associated abscesses and relations with the anal sphincter complex and its role in preoperative classification.

Material & methods

A retrospective study was carried out using picture archiving and communication system. Data of 58 patients presented with a clinical suspicious of perianal fistula from April 2012 to March 2013 was collected. In all patients pre contrast T2 propeller with and without fat suppression, diffusion weighted and pre and post contrast liver acceleration volume acquisition sequences were obtained. Pulse sequences were as follows: T2 propeller (TR: 7766 ms, TE: 122 ms), Diffusion weighted (TR: 7000 ms, TE: 67 ms), LAVA (TR: 7 ms, TE: 3.242 ms).

Results

MRI revealed a total number of 38 fistulae in 35 (60%) patients while 13 (22%) patients had only perianal sinuses. Out of these 35 patients, 4 were females and 31 were male subjects. Out of total 38 fistulae seen in these 35 patients, 11 (29%) were transsphincteric, 24 (63%) were intersphincteric and 2 (5%) were suprasphincteric. Only 1 (3%) case was extrasphincteric fistula. Twenty-six fistulae (68%) were simple, whereas 12 (32%) showed associated abscess formation, inflammation and branching course.

Conclusion

Our results support that MRI is the method of choice for evaluating perianal fistulae as they display the anatomy of the sphincter muscles orthogonally with a background of good contrast resolution. Moreover, with MRI we can accurately classify perianal fistulas preoperatively along with the detection of associated infection and help in planning a successful surgery.     

Preoperative MR imaging of anal fistulas: Does it really help the surgeon?

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) imaging with a quadrature phased-array coil for the detection of anal fistulas and to evaluate the additional clinical value of preoperative MR imaging, as compared with surgery alone. MATERIALS AND METHODS: Fifty-six patients with anal fistulas underwent high-spatial-resolution MR imaging. Twenty-four had a primary fistula; 17, a recurrent fistula; and 15, a fistula associated with Crohn disease. MR imaging findings were withheld from the surgeon until surgery ended and verified, and surgery continued when required. RESULTS: MR imaging provided important additional information in 12 (21%) of 56 patients. In patients with Crohn disease, the benefit was 40% (six of 15); in patients with recurrent fistulas, 24% (four of 17); and in patients with primary fistulas, 8% (two of 24). The difference between patients with or without Crohn disease and between patients with a simple fistula versus the rest was significant (P <.05). The sensitivity and specificity for detecting fistula tracks were 100% and 86%, respectively; abscesses, 96% and 97%, respectively; horseshoe fistulas, 100% and 100%, respectively; and internal openings, 96% and 90%, respectively. CONCLUSION: High-spatial-resolution MR imaging is accurate for detecting anal fistulas. It provides important additional information in patients with Crohn disease-related and recurrent anal fistulas and is recommended in their preoperative work-up.     

Perianal complications of Crohn disease: MR imaging findings

The aim of this study was to revisit anal anatomy, to explain surgical terminology in perianal complications of Crohn disease, and to show the MR imaging findings of perianal fistulas and abscesses. To this end more than 200 patients were studied using surface coils (Helmholtz; phased array) at 1.0 and 1.5 T. Transverse and coronal T1- and T2-weighted images were obtained. Parks' classification was used to describe perianal abscesses and fistulas. This pictorial essay shows the normal anal anatomy and pathologic findings such as subcutaneous, para-anal, ischiorectal, intersphincteric, and supralevatoric abscesses and fistulas. MR imaging with surface coils is well suited to showing the anal anatomy and to reliably describing perianal abscesses and fistulas according to surgical terminology. Received: 7 October 1996; Revision received 4 December 1996; Accepted 10 December 1996     

Breathhold MRI of the small bowel in Crohn's disease after enteroklysis with oral magnetic particles

Purpose: To evaluate the efficacy of breathhold MRI following enteroclysis with addition of oral magnetic particles to study the extension, detection of stenoses and extraluminal manifestations in Crohn's disease. Material and Methods: 18 patients with Crohn's disease and potential of surgical intervention were studied with enteroclysis with addition of oral magnetic particles. T1-/T2-weighted breathhold MRI w/o spectral fat suppression w/o i. v. Gd-DTPA was applied. Results: Typical findings were marked bowel wall thickening with strong contrast enhancement. 95.8 % of affected small bowel segments and 94.7 % of stenoses were correctly detected by MRI. All four fistulas were detected and important extraluminal findings were seen in 6/18 patients. Additionally, one ileoileal and two ileosigmoidal adhesions, two extraluminal abscesses and affection of the right ureter were delineated. Conclusion: MRI in Crohn's disease offers the potential to avoid radiation exposure in this relatively young patient group. Important additional findings relevant to indication of surgery are seen in approximately one third of cases. The replacement of transduodenal intubation by oral contrast application remains to be further studied.      

自制可调节肛肠水囊在普通MRI肛瘘术前分型中的应用

目的:初步评价自制可调节肛肠水囊在肛瘘患者术前普通MRI分型中的应用价值。方法:使用Philips 1.5 TAchievaDual MR扫描仪和体线圈对18例经手术证实的肛瘘患者在放置自制可调节肛肠水囊前、后均各行一次MRI检查。序列包括TSE的T_1WI及T_2WI SPAIR横断位和冠状位。放置水囊前后比较瘘管末端位置,并且对瘘管、分支及脓腔进行计数。结果用于评估肛瘘临床术前分型,同时与手术结果相对照。结果:18例肛瘘患者MRI检查共发现瘘管31根、分支19根、内口22个以及脓腔10个。使用水囊前后,MRI对瘘管末端位置的显示有显著不同(x~2=5.56,P0.05)。使用水囊前,MR显示1例为低位单纯型、2例为低位复杂型、2例为高位单纯型、8例为高位复杂型肛瘘,5例无法确定;使用水囊后,相应数据分别为1、2、3、11例,1例无法确定。使用水囊前后,MRI对肛瘘的分型与手术的相符率分别为72%(13例)和94%(17例),差异无统计学意义(P=0.08)。结论:通过使用自制可调节肛肠水囊,普通MRI能够提供更多有关瘘管及其走行的信息,有助于肛瘘患者的术前分型。     

T1 WI SPIR增强MRI在肛瘘中的应用价值

目的通过T1WI频谱预饱和反转恢复序列(SPIR)钆增强MRI与其他常规MRI序列比较,评估增强T1WI SPIR MRI在使用肛肠水囊肛瘘患者中的临床应用价值。资料与方法16例经手术证实的肛瘘患者术前均行MRI检查,序列包括横断位T1WI、T2WI频谱选择性衰减反转恢复序列(SPAIR)和钆增强T1WI SPIR。检查前,均向患者肛管直肠内置入肛肠水囊以撑开肛管和直肠。评估和比较MRI各序列显示的瘘管、内口、瘘管分支及脓腔。结果MRI显示复杂性肛瘘11例,其中高位复杂性肛瘘6例,单纯性5例。对比增强T1WI SPIR MRI发现瘘管(100.0%)、内口(81.3%)、分支(81.3%)和脓腔(100.0%)的准确率较T1WI及T2WI SPAIR MRI为高。Kruskal-Wallis检验显示上述各序列对内口显示的差异有显著统计学意义(χ2=15.9,P=0.003)。对比增强T1WISPIR MRI显示内口最多。结论横断位钆增强T1WI SPIR序列在使用肛肠水囊后能提供患者瘘管更丰富的细节,提高肛瘘诊断的准确率。     

体部表面线圈磁共振成像对肛瘘的术前诊断价值

目的:探讨体部表面线圈MRI对肛瘘的术前诊断价值。材料和方法:回顾性分析42例肛瘘患者,均于术前进行非增强MRI检查,将MRI结果与手术结果对照。结果:MRI诊断结果与手术结果一致,其中23例为括约肌间型,5例经括约肌型,5例括约肌上型,9例括约肌外型,所有病例中有12例可见肛周脓肿形成。结论:MRI作为一种安全、准确的肛瘘检查方法,对于肛瘘的术前诊断具有非常重要的价值。     

肛瘘的MIR诊断

目的 探讨肛瘘的MRI表现与诊断价值。材料与方法 16例肛瘘患者,MRI行冠状面及横断面STIR序列扫描,冠状面及横断面FFE序列平扫及Gd-DTPA增强扫描,检查结果与手术对照。结果 11例简单肛瘘,5例复杂肛瘘,MR检查结果与手术结果一致。STIR序列图像上,瘘管及肛周脓肿表现为条状及片状高信号。在FFE序列平扫图像上,瘘管及肛周脓肿表现为条状及片状低信号,增强扫描后瘘管及脓肿壁明显强化。结论 MRI是一种快速、无损伤及具有准确性相当高的肛瘘检查方法,能提供外科手术所需的解剖及病理资料。     

CT imaging with fistulography for perianal fistula: does it really help the surgeon?

ObjectiveTo prospectively evaluate the relative accuracy of computed tomography (CT) fistulography for preoperative assessment of fistula in ano.Materials and MethodsEthical committee approval and informed consent were obtained. A total of 22 patients (15 male and 7 female, age 21–58 years) who were suspected of having fistula in ano underwent preoperative CT fistulography (CTF). The CT images of 0.6 mm were obtained respectively before and after fistulography; contrast-enhanced CT scan was also performed in 22 patients. CTF images were evaluated by two expert radiologists to assess the fistulas in the following respects: (a) the volume-rendered imaging; (b) the extensions of active inflammatory tissue; (c) the internal opening and external opening; (d) the hidden areas of tract or abscess; and (e) the deep abscess adjacent to fistula. CT findings in 18 patients were compared with surgical findings or exam under anesthesia.ResultsThe CTF findings in 18 cases were basically in accordance with the surgical findings and/or examination findings under anesthesia. Both coronal and transverse planes were useful in assessing the location and direction of tracts or abscesses. Complicated spatial information within the perianal soft tissue about the fistula with secondary ramifications or abscesses can be easily demonstrated to the surgeons. Contrast-enhanced images were useful in assessing the inflammatory lesion activity and infiltrated area.ConclusionCTF exquisitely depicts the perianal anatomy and shows the fistulous tracks with their associated ramifications, enables selection of the most appropriate surgical treatment, and therefore minimizes all chances of recurrence.     

高分辨率MRI在复杂性肛瘘诊断中的价值研究

目的:探讨复杂性肛瘘的MRI表现及其临床诊断价值。方法:48例可疑复杂性肛瘘患者,行盆腔MR平扫检查,扫描序列包括横断面FSE-T1WI、T2WI、T2WI抑脂及STIR扫描,矢状面STIR及T2WI扫描,冠状面STIR及T2WI抑脂扫描。分析肛瘘的MRI表现,评价瘘管与内外括约肌的关系及复杂性肛瘘的分型,比较内、外口的显示率,将诊断结果与手术进行对照。结果:瘘管于T1WI表现为条状略低信号,T2WI、T2WI抑脂及STIR序列呈明显高信号,以抑脂像病灶显示最佳。MR诊断与手术比较符合率分别为:肛瘘(或脓肿)96.9%,内口82.4%,外口100%,分型86.7%。结论:MRI是复杂性肛瘘的一种重要诊断方法,具有重要的临床价值。