Imaging of Anal Fistulas: Comparison of Computed Tomographic Fistulography and Magnetic Resonance Imaging

The primary importance of magnetic resonance (MR) imaging in evaluating anal fistulas lies in its ability to demonstrate hidden areas of sepsis and secondary extensions in patients with fistula in ano. MR imaging is relatively expensive, so there are many healthcare systems worldwide where access to MR imaging remains restricted. Until recently, computed tomography (CT) has played a limited role in imaging fistula in ano, largely owing to its poor resolution of soft tissue. In this article, the different imaging features of the CT and MRI are compared to demonstrate the relative accuracy of CT fistulography for the preoperative assessment of fistula in ano. CT fistulography and MR imaging have their own advantages for preoperative evaluation of perianal fistula, and can be applied to complement one another when necessary.     

Neck infection associated with pyriform sinus fistula: imaging findings

BACKGROUND AND PURPOSE: Acute suppurative neck infections associated with branchial fistulas are frequently recurrent. In this study, we describe the imaging findings of acute suppurative infection of the neck caused by a third or fourth branchial fistula (pyriform sinus fistula). METHODS: Imaging findings were reviewed in 17 patients (11 female and six male patients, 2 to 49 years old) with neck infection associated with pyriform sinus fistula. Surgery or laryngoscopic examination confirmed the diagnoses. Fourteen patients had a history of recurrent neck infection and seven had cutaneous openings on the anterior portion of the neck (all lesions were on the left side). Imaging studies included barium esophagography (n = 16), CT (n = 14), MR imaging (n = 2), and sonography (n = 3). RESULTS: A sinus or fistulous tract was identified in eight of 16 patients on barium esophagograms. In 14 patients, CT studies showed the inflammatory infiltration and/or abscess formation along the course of the sinus or fistulous tract from the pyriform fossa to the thyroid gland. In nine patients, CT scans showed the entire course or a part of the sinus or fistulous tract as a tiny spot containing air. MR images showed a sinus or fistulous tract in two patients, whereas sonograms could not depict a sinus or fistulous tract in three patients. All 17 patients were treated with antibiotics. In one patient, the sinus tract was surgically excised, while 15 patients underwent chemocauterization of the sinus or fistulous tract with good outcome. Follow-up was possible for 16 of the 17 patients. CONCLUSION: When an inflammatory infiltration or abscess is present between the pyriform fossa and the thyroid bed in the lower left part of the neck, an infected third or fourth branchial fistula should be strongly suspected.     

Clinical examination, endosonography, and MR imaging in preoperative assessment of fistula in ano: comparison with outcome-based reference standard

PURPOSE: To prospectively evaluate the relative accuracy of digital examination, anal endosonography, and magnetic resonance (MR) imaging for preoperative assessment of fistula in ano by comparison to an outcome-derived reference standard. MATERIALS AND METHODS: Ethical committee approval and informed consent were obtained. A total of 104 patients who were suspected of having fistula in ano underwent preoperative digital examination, 10-MHz anal endosonography, and body-coil MR imaging. Fistula classification was determined with each modality, with reviewers blinded to findings of other assessments. For fistula classification, an outcome-derived reference standard was based on a combination of subsequent surgical and MR imaging findings and clinical outcome after surgery. The proportion of patients correctly classified and agreement between the preoperative assessment and reference standard were determined with trend tests and kappa statistics, respectively. RESULTS: There was a significant linear trend (P < .001) in the proportion of fistula tracks (n = 108) correctly classified with each modality, as follows: clinical examination, 66 (61%) patients; endosonography, 87 (81%) patients; MR imaging, 97 (90%) patients. Similar trends were found for the correct anatomic classification of abscesses (P < .001), horseshoe extensions (P = .003), and internal openings (n = 99, P < .001); endosonography was used to correctly identify the internal opening in 90 (91%) patients versus 96 (97%) patients with MR imaging. Agreement between the outcome-derived reference standard and digital examination, endosonography, and MR imaging for classification of the primary track was fair (kappa = 0.38), good (kappa = 0.68), and very good (kappa = 0.84), respectively, and fair (kappa = 0.29), good (kappa = 0.64), and very good (kappa = 0.88), respectively, for classification of abscesses and horseshoe extensions combined. CONCLUSION: Endosonography with a high-frequency transducer is superior to digital examination for the preoperative classification of fistula in ano. While MR imaging remains superior in all respects, endosonography is a viable alternative for identification of the internal opening.     

Magnetic resonance imaging evaluation of perianal fistula

Aim of work

To clarify the role of MRI in diagnosis and classification of perianal fistula and to evaluate the additional clinical value of preoperative MR imaging and its benefit to surgeon.

Methods

This prospective study contained 25 patients (21 males and 4 females; age range 10–60 years; mean age 34.8 years) selected from 40 patients referred to the Radiodiagnosis department with perianal sepsis, the study was conducted between October 2009 and September 2011, MRIs were performed and the results were ensured by surgical results, sensitivity, specificity and predictive values of MRIs were determined.

Results

25 patients with perianal sepsis were included in this study, 3 cases grade 1 (simple linear intersphincteric fistula), 2 cases grade 2 (intersphincteric fistula with abscess or secondary track), 9 cases grade 3 (trans-sphincteric fistula), 9 cases grade 4 (trans-sphincteric fistula with abscess (5 cases), secondary track within the ischiorectal fossa (3 cases) and both (1 case)) and 2 cases grade 5 (supralevator and translevator disease one case for each).

Conclusion

MRI is a useful procedure for successful management of peri-anal fistula by correct assessment of the extent of disease and relationship to sphincter complex. Also it helps in identification of secondary extensions, particularly horseshoe tracts and abscesses resulting in complete evaluation and highest possible diagnostic accuracy aiding successful surgical interventions, aiming to reduce complications and recurrences.     

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.     

Suspected dural arteriovenous fistula: results with screening MR angiography in seven patients.

Previous studies have shown that spin-echo (SE) magnetic resonance (MR) imaging has been helpful in the assessment of dural arteriovenous fistula (DAVF); however, direct visualization of the fistula site is limited. Thus, conventional plain angiography is required to establish the diagnosis. Because of this limitation, the additional use of MR angiography may improve noninvasive screening for this disorder. Seven patients with DAVFs proved at plain angiography were evaluated with SE MR imaging and with three-dimensional (3D) time-of-flight (TOF) MR angiography. In six of seven cases, 3D TOF MR angiography demonstrated the fistula site. Correlation was good when compared with findings at plain angiography. Occlusion of the dural sinus was found at plain angiography in three of seven patients but was missed at SE imaging in all three. MR angiography also failed to demonstrate sinus occlusion in two of three patients. Arterial feeders could not be seen on SE MR images, but MR angiography improved their depiction. Plain angiography demonstrated abnormal venous drainage into distended cortical veins in three patients, but dilated cortical veins were noted in only two of the patients on both SE MR images and MR angiograms.     

Secondary cleft sign as a marker of injury in athletes with groin pain: MR image appearance and interpretation

PURPOSE: To determine whether the secondary cleft sign demonstrated in the symphysis pubis at magnetic resonance (MR) imaging is a marker of injury in athletes presenting with groin pain. MATERIALS AND METHODS: Ethics review board approval was not required for studies involving retrospective image or case record review; informed consent for review was not required. Eighteen male athletes (mean age, 24 years; age range, 19-32 years) were included for study. All patients underwent radiography and MR imaging (coronal fast spin-echo T1-weighted, transverse fast spin-echo T2-weighted, and coronal turbo short inversion time inversion-recovery [STIR] imaging) of the pelvis. Subsequent image-guided nonionic contrast material injection was followed by a 0.5% bupivacaine hydrochloride (1 mL) and methyprednisolone acetate (20 mg) injection into the central cleft of the symphysis pubis. Comparison was made between imaging findings at symphyseal cleft injection and appearances at preprocedure MR imaging, with specific reference to the presence of a secondary cleft. The sensitivity and specificity of MR imaging in demonstrating the secondary cleft sign were compared with those of the reference standard, imaging at symphyseal cleft injection. MR images from a reference group of 70 asymptomatic athletes who underwent STIR imaging of the pelvis were analyzed for evidence of a secondary cleft. RESULTS: Osteitis pubis was diagnosed in six patients on the basis of radiography and/or MR imaging. A secondary cleft was identified in 12 of 18 patients at MR imaging, was best visualized at coronal STIR imaging, and was confirmed in each patient during contrast material injection into the central physiologic symphyseal cleft. In no patient was a secondary cleft identified at symphyseal cleft injection and not identified at MR imaging (sensitivity and specificity, 100%). In each patient, the side of the secondary cleft corresponded to the side of symptoms that responded to local anesthetic and steroid injection. Four of the six patients with osteitis pubis had evidence of a secondary cleft. In one patient, a secondary cleft was not identified at MR imaging or symphyseal cleft injection, but adductor avulsion was identified at MR imaging. No evidence of a secondary cleft sign at MR imaging was identified in the reference group. CONCLUSION: The secondary cleft sign demonstrated at MR imaging is a marker of groin injury in athletes presenting with groin pain.     

A retrospective analysis of spontaneous sphenoid sinus fistula: MR and CT findings

BACKGROUND AND PURPOSE: The sphenoid sinus is rarely implicated as a site of spontaneous CSF fistula. We undertook this study to evaluate the potential etiopathogenesis of spontaneous CSF fistula involving the sphenoid sinus and to review the imaging findings. METHODS: We retrospectively reviewed the imaging findings of 145 cases of CSF fistula from our departmental archives (August 1995 through August 1998). Fifteen (10%) patients had CSF fistulas involving the sphenoid sinus. Eleven (7%) patients had spontaneous CSF fistulas, whereas in four patients, the CSF fistulas in the sphenoid sinus were related to trauma. Of the 11 patients, nine underwent only plain high-resolution CT and MR cisternography. One patient additionally underwent contrast-enhanced CT cisternography, and one other patient underwent MR cisternography only. For each patient, the CSF fistula site was surgically confirmed. The MR imaging technique included T1-weighted and fast spin-echo T2-weighted 3-mm-thick coronal sequences obtained with the patient in the supine position. The plain high-resolution CT study included 3-mm-thick, and sometimes 1- to 1.5-mm-thick, coronal sections obtained with the patient in the prone position. Similar sections were obtained after injecting nonionic contrast material intrathecally via lumbar puncture for the CT cisternographic study. We evaluated each of the 11 patients for the exact site of CSF leak in the sphenoid sinus. We also determined the presence of pneumatization of lateral recess of the sphenoid sinus, orientation of the lateral wall of the sphenoid sinus, presence of arachnoid pits, presence of brain tissue herniation, and presence of empty sella in each of these patients. RESULTS: The exact sites of the CSF fistulas were documented for all 11 patients by using plain high-resolution CT, MR cisternography, or CT cisternography. In nine (82%) patients, the sites of the CSF fistulas were at the junction of the anterior portion of the lateral wall of the sphenoid sinus and the floor of the middle cranial fossa. In the remaining two (18%) patients, the sites of the CSF fistulas were along the midportion of the lateral wall of the sphenoid sinus. Of these 11 patients, one had bilateral sites of the CSF fistula at the junction of the anterior portion of the lateral wall of the sphenoid sinus with the floor of the middle cranial fossa. In nine (82%) patients, the presence of brain tissue herniation was revealed, and this finding was best shown by MR cisternography. Ten (91%) patients had extensive pneumatization of the lateral recess of the sphenoid sinus, with an equal number having outward concave orientation of the inferior portion of the lateral wall of the sphenoid sinus. In seven (63%) patients, the presence of arachnoid pits, predominantly along the anteromedial aspect of the middle cranial fossa, was shown. In seven (63%) patients, empty sella was shown. For comparison, we reviewed the CT studies of the paranasal sinuses in 100 age-matched control subjects from a normal population. Twenty-three had extensive lateral pneumatization of the sphenoid sinus along with outward concavity of the inferior portion of the lateral wall. None of these 23 patients had arachnoid pits. CONCLUSION: The sphenoid sinus, when implicated as a site of spontaneous CSF leak, yields a multitude of imaging findings. These are extensive pneumatization of the lateral recess of the sphenoid sinus, outward concave orientation of the inferior portion of the lateral wall of the sphenoid sinus, arachnoid pits, and empty sella. Considering the normative data, we speculate that this constellation of findings could play a role in the etiopathogenesis of spontaneous sphenoid sinus fistulas. Our findings also show the efficacy of noninvasive imaging techniques, such as plain high-resolution CT and MR cisternography, in the evaluation of sphenoid sinus CSF leak. Our data also suggest that spontaneous sphenoid sinus CSF leak is not an uncommon occurrenc     

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.     

Typical MR imaging findings of perianal infections in patients with hematologic malignancies

ObjectiveWe aimed to investigate the MR imaging findings of patients with hematologic malignancies who have symptoms suggesting perianal infection and to demonstrate the importance of imaging.Subjects and methodsThe study included 36 patients with hematologic malignancies who underwent anorectal MR imaging in our department between September 2011–May 2016. Two radiologists experienced in abdominal radiology viewed the MR images in consensus. Abscesses, fistulous or sinus tracts, signal alterations and contrast enhancement in keeping with an inflammation and edema in the perianal region were recorded.ResultsPerianal abscess was found in 16 of the 36 patients. In 10 of these 16 patients there was also extensive inflammatory signal alterations in perianal and/or perineal soft tissues.In six of the 36 patients perianal fistula was detected. A sinus tract was seen at the level of subcutaneous external anal sphincter in one patient. Inflammatory signal alterations in the surrounding soft tissues were present in three of these seven patients.There were abscesses in labium majus in two patients and in one patient there were perineal abscesses with accompanying inflammatory signal alterations.In six of the 36 patients no abscess or fistula/sinus tract was seen. There were only inflammatory signal alterations with contrast enhancement in perianal or subcutaneous tissues.In two patients presenting with perianal pain and hemorrhoids, minimal inflammatory changes were detected on MR images.There were two patients with normal MR imaging findings.ConclusionAs digital examination of the anorectum and rectoscopy are avoided in neutropenic patients, MR imaging, which clearly demonstrates the perianal pathology should be preferential.     

Anovaginal and rectovaginal fistulas: endoluminal sonography versus endoluminal MR imaging

OBJECTIVE: The exact location of anovaginal and rectovaginal fistulas cannot be determined by physical examination and conventional techniques. The objective of our study was to compare the accuracy of endoluminal sonography and endoluminal MR imaging in revealing the location of anovaginal and rectovaginal fistulas. MATERIALS AND METHODS: Nineteen consecutive patients (age range, 28-56 years; median age, 39 years) with clinical indications of an anovaginal or rectovaginal fistula were included in our retrospective study. Endoluminal sonography was performed using a 7.5-MHz transducer. Endoluminal MR imaging was performed at 0.5 T for 10 patients and 1.5 T for nine patients; axial T2-weighted gradient-echo, coronal and sagittal T2-weighted turbo spin-echo (0.5 T), or axial and radial T2-weighted turbo spin-echo and axial T2-weighted fat saturated turbo spin-echo (1.5 T) images were obtained. For a variety of reasons, surgery of the fistula was not attempted in six of these 19 patients. The imaging findings were compared with the findings obtained during surgery in the remaining 13 patients. RESULTS: In 12 of the 13 patients, the fistula was found during surgery: seven of the fistulas were anovaginal, and five were rectovaginal. Findings of endoluminal sonography were true-positive in 11 patients, true-negative in one, and false-negative in one. Findings of endoluminal MR imaging were true-positive in 11 patients, false-negative in one, and false-positive in one. Positive predictive value for endoluminal sonography and endoluminal MR imaging were 100% and 92%, respectively. Imaging findings for anal sphincter defects were comparable. CONCLUSION: Endoluminal sonography and endoluminal MR imaging have comparable positive predictive values in revealing the location of anovaginal and rectovaginal fistulas.     

Cavernous sinus and inferior petrosal sinus flow signal on three-dimensional time-of-flight MR angiography.

BACKGROUND AND PURPOSE: Venous flow signal in the cavernous sinus and inferior petrosal sinus has been shown on MR angiograms in patients with carotid cavernous fistula (CCF). We, however, identified flow signal in some patients without symptoms and signs of CCF. This review was performed to determine the frequency of such normal venous flow depiction at MR angiography. METHODS: Twenty-five 3D time-of-flight (TOF) MR angiograms obtained on two different imaging units (scanners A and B) were reviewed with attention to presence of venous flow signal in the cavernous sinus or inferior petrosal sinus or both. Twenty-five additional MR angiograms were reviewed in patients who had also had cerebral arteriography to document absence of CCF where venous MR angiographic signal was detected, as well as to gain insight into venous flow patterns that might contribute to MR angiographic venous flow signal. Differences in scanning technique parameters were reviewed. RESULTS: Nine (36%) of the 25 MR angiograms obtained on scanner A but only one (4%) of the 25 obtained on scanner B showed flow signal in the cavernous or inferior petrosal sinus or both in the absence of signs of CCF. On review of 25 patients who had both MR angiography and arteriography, three patients with venous signal at MR angiography failed to exhibit CCF at arteriography. CONCLUSION: Identification of normal cavernous sinus or inferior petrosal sinus venous signal on 3D TOF MR angiograms may occur frequently, and is probably dependent on technical factors that vary among scanners. The exact factors most responsible, however, were not elucidated by this preliminary review.     

Intracranial dural arteriovenous fistulas: evaluation with combined 3D time-of-flight MR angiography and MR digital subtraction angiography

OBJECTIVE: The purpose of this study was to compare the diagnostic utility of 3D time-of-flight (TOF) MR angiography and MR digital subtraction angiography in patients with angiographically proven moderate- to high-flow intracranial dural arteriovenous fistula. MATERIALS AND METHODS: Two neuroradiologists, unaware of patients' histories and angiographic findings, retrospectively reviewed 17 MR angiograms with 3D TOF MR angiography and MR digital subtraction angiography in 15 patients with dural arteriovenous fistula and also reviewed 35 MR angiograms in control patients without findings of dural arteriovenous fistula on angiography. Disagreements were resolved by consensus. RESULTS: In patients with dural arteriovenous fistula, source images of 3D TOF MR angiography showed two abnormal findings: multiple high-intensity curvilinear or nodular structures adjacent to the sinus wall and high-intensity areas in the venous sinus. Findings of multiple high-intensity structures adjacent to the sinus wall were observed in all cases of dural arteriovenous fistula. Findings of high-intensity areas in the venous sinus were observed in 13 of 17 cases of dural arteriovenous fistula. Findings of multiple high-intensity structures adjacent to the sinus wall were not observed in any control subjects. Findings of high-intensity areas within the venous sinus were observed in five of 35 control subjects. Findings of MR digital subtraction angiography showed early filling of the venous sinus, suggestive of dural arteriovenous fistula, in 13 of 15 patients with dural arteriovenous fistula. Sensitivity and specificity of multiple high-intensity structures adjacent to the sinus wall, high-intensity areas in the venous sinus, and early filling of the venous sinus were 100% and 100%, 76% and 86%, and 87% and 100%, respectively. Although 3D TOF MR angiography failed to show the findings of retrograde cortical venous drainage and venous sinus occlusion, MR digital subtraction angiography clearly showed both findings in all five subjects. CONCLUSION: A protocol including both 3D TOF MR angiography (source images) and MR digital subtraction angiography allowed the diagnosis of moderate- to high-flow dural arteriovenous fistula. In addition, cortical venous drainage was reliably noted in a small subset of patients.     

Tortuous, engorged pial veins in intracranial dural arteriovenous fistulas: correlations with presentation, location, and MR findings in 122 patients.

BACKGROUND AND PURPOSE: Tortuous, engorged veins can be identified on the venous phase of the brain circulation in patients with venous congestion related to an intracranial dural arteriovenous fistula (DAVF). The term pseudophlebitic pattern (PPP) has been used to describe this finding. The purpose of this study was to determine the prevalence of PPP in patients with intracranial DAVF and to analyze the relationship of this sign to presentation, location of the fistula, presence of retrograde leptomeningeal venous drainage, and MR findings. METHODS: We retrospectively reviewed the charts and imaging findings of 130 patients with intracranial DAVF. In 122 patients the venous phase of the brain circulation was adequately assessed. The PPP was graded as mild, moderate, or severe. RESULTS: PPP was found in 51 patients (42%). Thirty-two (73%) of the 44 patients who had a hemorrhage, neurologic deficit, or seizure had PPP as compared with 16 (21%) of the 75 who had a bruit or orbital signs. The three patients with either congestive heart failure or increasing head circumference had PPP. Fourteen (88%) of the 16 who had fistula of the superior sagittal sinus, straight sinus, or superior petrosal sinus had PPP. PPP was seen in 46 (81%) of 57 patients who had retrograde leptomeningeal venous drainage and in five (8%) of the 65 who had only sinosal drainage. Fourteen (88%) of the 16 who had white matter T2 hyperintensity on MR images had severe PPP. CONCLUSION: The PPP reflects venous congestion and is associated with an aggressive presentation with or without retrograde leptomeningeal venous drainage. PPP may be a useful prognostic indicator and should be considered in treatment decisions.     

MR imaging and MR angiography in the evaluation of pulsatile tinnitus.

PURPOSE1) To evaluate the scope of imaging findings seen with spin-echo MR and MR angiography (MRA) in patients with pulsatile tinnitus; 2) to determine whether MRA adds additional imaging information (to that provided by spin-echo MR) necessary for determining the cause of pulsatile tinnitus; and 3) to suggest MR and MRA imaging techniques for evaluation of patients with pulsatile tinnitus.METHODSForty-nine patients with pulsatile tinnitus were evaluated with MR and MRA. Seventeen of these patients had conventional angiography.RESULTSVascular lesions or paraganglioma were demonstrated in 28 patients. Of these 28 lesions, the majority were seen best (46%) or only (36%) on MRA. The spectrum of lesions detected included dural arteriovenous fistula (nine), extracranial arteriovenous fistula (three), paraganglioma (five), jugular bulb variants (three), aberrant internal carotid artery (one), internal carotid artery stenosis (one), tortuous internal carotid artery (one), carotid dissection with pseudoaneurysm (one), stenosis of the transverse sinus (two), and arteriovenous malformation (two).CONCLUSIONSMRA, in conjunction with spin-echo imaging, markedly enhances the ability of MR to diagnose the lesions responsible for pulsatile tinnitus.     

Imaging of fistula in ano

Fistula in ano is a common condition that often recurs despite seemingly adequate surgery, usually because of infection that was missed at surgery. It is now increasingly recognized that preoperative imaging can help identify infection that would have otherwise gone unidentified. In particular, magnetic resonance (MR) imaging findings have been shown to influence surgery and markedly diminish the chance of recurrence; thus, preoperative imaging will become increasingly routine in the future. In this article, the authors describe the pathogenesis, classification, and imaging of fistula in ano, with an emphasis on MR imaging. Most important, the authors describe how the radiologist is well placed to answer the surgical riddles that must be solved for treatment to be effective.     

Transperineal and transvaginal sonography of perianal inflammatory disease

OBJECTIVE: Perianal infection arises in small intersphincteric anal glands predominantly located at the dentate line. Documentation of fluid collections and the relationship of inflammatory tracts to the sphincter mechanism is important for surgical treatment. Transanal sonography for assessment of perianal inflammatory disease is limited because placement of the rigid probe into the anal canal does not allow assessment of disease in the perineal region. The purpose of this study was to validate the use of transperineal sonography in men and both transvaginal and transperineal sonography in women for evaluation of perianal inflammatory disease. SUBJECTS AND METHODS: Fifty-four patients, 28 men and 26 women, were imaged with transperineal and a combination of transperineal and transvaginal sonography, respectively. All patients were examined in the supine lithotomy and left lateral position with a transvaginal 8-to 4-MHz probe or a linear 12- to 7-MHz transducer. All fluid collections, sinus tracts, and fistulas were described by their location in relation to the sphincter mechanism and perineum. RESULTS: Forty-six of 54 patients had perianal fistulas or sinus tracts: 33 transphincteric, seven intersphincteric, and six extrasphincteric. Fifteen patients had an associated abscess. In the eight remaining patients, there were two anovaginal fistulas, one rectovaginal fistula, one prolapsed internal hemorrhoid, two perianal complex masses, and two vascular perianal or perirectal inflammatory masses. Twenty-six patients underwent surgical procedures involving the anorectal canal or perirectal region, and of these, preoperative sonographic findings were confirmed in 22 (85%) of 26 patients. Three patients refused surgery, and six are awaiting surgery at this writing. Fifteen patients were treated conservatively. CONCLUSION: Transperineal and transvaginal sonography are accurate, painless, and cost-effective methods for documenting perianal fluid collections and fistulas or sinus tracts or both.     

Treated ovarian cancer: MR imaging, laparotomy reassessment, and serum CA-125 values compared with clinical outcome at 1 year

PURPOSE: To compare retrospectively the use of magnetic resonance (MR) imaging, laparotomy reassessment, and serum CA-125 values in predicting the presence of residual tumor in women who have been treated for ovarian cancer. MATERIALS AND METHODS: This study was approved by the institutional review board, and informed consent was waived. The study was compliant with the Health Insurance Portability and Accountability Act. Seventy-six women (mean age, 59 years) with treated ovarian cancer underwent preoperative MR imaging of the abdomen and pelvis with intravenous gadolinium-based and intraluminal barium contrast material. MR findings were compared with surgical and histopathologic findings, serial and static serum CA-125 values, and clinical follow-up results. Tumor absence was proved with normal surgical results and by following up patients for at least 1 year, with no evidence of residual tumor at serial CA-125 analysis or subsequent laparotomy. McNemar test for correlated proportions was used for statistical analysis. RESULTS: Sixty-eight women had residual tumor proved at laparotomy and biopsy or at clinical follow-up. Eight patients had no evidence of residual tumor. Gadolinium-enhanced MR imaging depicted residual tumor in 61 patients (sensitivity, 90%; specificity, 88%; accuracy, 89%) compared with laparotomy, which demonstrated residual tumor in 60 patients (sensitivity, 88%; specificity, 100%; accuracy, 89%) and CA-125 values, which demonstrated residual tumor in 44 patients (sensitivity, 65%; specificity, 88%; accuracy, 67%) (P < .01). The positive predictive values for MR imaging, laparotomy, and serum CA-125 values were 98%, 100%, and 98%, respectively, whereas the corresponding negative predictive values were 50%, 50%, and 23%, respectively. In 14 patients, there was a discrepancy between the results of MR imaging and those of laparotomy. In seven patients, MR imaging depicted residual tumor that was not found at laparotomy but was proved at subsequent biopsy or clinical and imaging follow-up, with an increasing serum CA-125 level. In six patients, MR findings were normal, and subsequent laparotomy revealed small-volume residual tumor. Residual tumor was incorrectly predicted with MR imaging in one patient who had no surgical or clinical evidence of residual tumor for 1 year. CONCLUSION: Gadolinium-enhanced spoiled gradient-echo MR imaging depicts residual tumor in women with treated ovarian cancer, with an accuracy, positive predictive value, and negative predictive value that are comparable to those of laparotomy and superior to those of serum CA-125 values alone.     

Dural sinus thrombosis: study using intermediate field strength MR imaging

The magnetic resonance (MR) images of six patients with thrombosis of a dural sinus were reviewed. The diagnosis had been verified by computed tomographic scans in three patients and arteriograms in two; in the sixth patient, only MR imaging was used to confirm the clinical syndrome. In all patients, high-intensity signal was seen from the thrombus within the affected dural sinus on all echoes. This persistent signal intensity allowed intravascular clot to be distinguished from normal causes of increased signal such as flow-related enhancement (entry phenomenon) and even-echo rephasing. MR imaging demonstrated the cause of the thrombosis in three patients: two were secondary to adjacent tumors, and one was secondary to unsuspected mastoiditis. Complications such as infarction were also demonstrated. Using MR imaging, one can easily and safely diagnose thrombosis of a dural sinus. MR should be the imaging method of choice in patients suspected of having thrombosis of a dural sinus.     

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