Synovitis and soft tissue impingement of the ankle: assessment with enhanced three-dimensional FSPGR MR imaging

PURPOSE: To assess soft tissue impingement as well as synovitis of the ankle associated with trauma by using contrast-enhanced (CE), fat-suppressed, three-dimensional, fast gradient-recalled acquisition in the steady state with radiofrequency spoiling (FSPGR) magnetic resonance (MR) imaging. MATERIALS AND METHODS: A total of 36 patients who had had chronic ankle pain associated with a traumatic injury undertook fat-suppressed CE three-dimensional FSPGR MR imaging and then arthroscopy of the ankle. The ankle joint was divided into four compartments by anatomic details: the anterolateral gutter, anteromedial gutter, anterior recess, and posterior recess. Synovial enhancement was graded as follows: grade I, no enhancement; grade II, linear enhancement; grade III, focal nodular enhancement; and grade IV, irregular nodular enhancement. MR grading of the synovial enhancement (synovitis, grade III or IV; soft tissue impingement, grade III or IV with its intrusion from the capsular reflection) was compared with arthroscopic findings. A control study of twenty asymptomatic ankles was done for determining enhancement. Arthroscopy confirmed synovitis in 47 compartments of 27 patients. Of the 27 patients, 15 revealed soft tissue impingement in 17 compartments. RESULTS: For the assessment of synovitis, fat-suppressed CE three-dimensional FSPGR MR imaging had an accuracy of 72.9%, sensitivity of 91.5%, and specificity of 63.9%; whereas for that of soft tissue impingement it had an accuracy of 94.4%, sensitivity of 76.5%, and specificity of 96.9%. All of the asymptomatic subjects showed grade I (81%) or II (19%) synovial enhancement. CONCLUSION: Fat-suppressed CE three-dimensional FSPGR MR imaging was sensitive for the evaluation of synovitis of the ankle associated with trauma, whereas it was specific for soft tissue impingement evaluation.     

踝关节前外侧软组织撞击综合征的MRI评价研究

目的:探讨MRI在踝关节前外侧软组织撞击综合征中的评价价值。方法:回顾性分析经临床、影像证实的踝关节前外侧软组织撞击综合征15例患者的MRI表现,主要观察踝关节前外侧沟内软组织、距腓前韧带、距腓前韧带前方脂肪、距腓前韧带旁积液等。结果:①踝关节前外侧沟内软组织影均不同程度增厚2～5mm(占100%);②距腓前韧带断裂9例(占60%),部分断裂2例(占13%),不能明确4例(占27%);③踝关节前外侧皮下脂肪影明显变薄10例(占67%),有不连续表现5例(占33%);④距腓前韧带旁明显积液11例(占73%),液体少4例(占27%);⑤滑膜增厚1例(占7%),无滑膜增厚14例(占93%);⑥胫骨远端骨髓水肿1例,距骨骨髓水肿3例,多个骨骨髓水肿1例。结论:MRI是评价踝关节前外侧软组织撞击综合征的最佳方法,能够清晰显示踝关节前外侧软组织病损情况及其他合并病变,可为临床诊断及治疗提供充分的资料。     

Magnetic resonance imaging findings in anterolateral impingement of the ankle

Objective. To demonstrate the MR imaging findings of anterolateral impingement (ALI) of the ankle. Design and patients. Nine patients with a history of ankle inversion injury and chronic lateral ankle pain were imaged with MR imaging, and the findings correlated with the results of arthroscopy. Three additional patients with clinically suspected ALI of the ankle were also included. Ankle MR imaging studies from 20 control patients in whom ALI was not suspected clinically were examined for similar findings to the patient group. Results. MR imaging findings in the patients with ALI included a soft tissue signal mass in the anterolateral gutter of the ankle in 12 of 12 (100%) cases, corresponding to the synovial hypertrophy and soft tissue mass found at arthroscopy in the nine patients who underwent arthroscopy. Disruption, attenuation, or marked thickening of the anterior talofibular ligament was seen in all cases. Additional findings included signs of synovial hypertrophy elsewhere in the tibiotalar joint in seven of 12 patients (58%) and bony and cartilaginous injuries to the tibiotalar joint in five of 12 (42%). None of the control patients demonstrated MR imaging evidence of a soft tissue mass in the anterolateral gutter. Conclusions. ALI of the ankle is a common cause for chronic lateral ankle pain. It has been well described in the orthopedic literature but its imaging findings have not been clearly elucidated. The MR imaging findings, along with the appropriate clinical history, can be used to direct arthroscopic examination and subsequent debridement. Received: 22 July 1999 Revision requested: 20 September 1999 Revision received: 7 October 1999 Accepted: 8 October 1999     

Detection of extracapsular extension of prostate cancer: role of fat suppression endorectal MRI

PURPOSE: The purpose of this work was to compare the efficacy of fat-suppressed and non-fat-suppressed fast spin echo (FSE) endorectal MRI in the detection of extracapsular extension (ECE) of prostate cancer by experienced and inexperienced readers. METHOD: Seventy-nine patients with biopsy-proven prostate cancer underwent axial FSE T2-weighted endorectal MRI of the prostate prior to radical prostatectomy. Twenty-one patients were imaged with frequency-selective fat suppression, and 58 were imaged without fat suppression. All images were retrospectively and independently reviewed by two readers of different experience levels who were blinded to clinical and pathological findings. Readers assessed the presence or absence of ECE on a 5 point scale for each side of the prostate, and step-section pathology was used as the standard of reference in all patients. Receiver operating characteristics analysis was used to compare the performance of fat-suppressed and non-fat-suppressed images by both readers. RESULTS: ECE was present in 33 of 79 (42%) patients. The more experienced reader demonstrated better diagnostic performance (p < 0.05) than the less experienced reader in terms of sensitivity and area under the ROC curve (Az) for MRI without fat suppression. Use of frequency-selective fat suppression did not result in any significant improvement in diagnosis of ECE compared with MRI without fat suppression for either the experienced (Az 0.81 vs. 0.79) or the inexperienced (Az 0.76 vs. 0.68) reader. CONCLUSION: Even when reader experience is considered, use of frequency-selective fat suppression did not significantly improve the diagnosis of ECE by MRI. The decision to use fat suppression and the selection of a fat suppression technique can be left to the discretion of the individual reader.     

Impingement syndrome of the ankle following supination external rotation trauma: MR imaging findings with arthroscopic correlation

Our objective was to identify MR imaging findings in patients with syndesmotic soft tissue impingement of the ankle and to investigate the reliability of these imaging characteristics to predict syndesmotic soft tissue impingement syndromes of the ankle. Twenty-one ankles with chronic pain ultimately proven to have anterior soft tissue impingement syndrome were examined by MR imaging during January 1996 to June 2001. The MR imaging protocol included sagittal and coronal short tau inversion recovery (STIR), sagittal T1-weighted spin echo, axial and coronal proton-density, and T2-weighted spin-echo sequences. Nineteen ankles that underwent MR imaging during the same period of time and that had arthroscopically proven diagnosis different than impingement syndrome served as a control group. Fibrovascular scar formations distinct from the syndesmotic ligaments possibly related to syndesmotic soft tissue impingement were recorded. Arthroscopy was performed subsequently in all patients and was considered the gold standard. The statistical analysis revealed an overall frequency of scarred syndesmotic ligaments of 70% in the group with ankle impingement. Fibrovascular scar formations distinct from the syndesmotic ligaments presented with low signal intensity on T1-weighted images and remained low to intermediate in signal intensity on T2-weighted MR imaging. Compared with arthroscopy, MR imaging revealed a sensitivity of 89%, a specificity of 100%, and a diagnostic accuracy of 93% for scarred syndesmotic ligaments. The frequency of scar formation distinct from the syndesmotic ligaments in patients with impingement syndrome of the ankle was not statistically significantly higher than in the control group. In contrast to that, anterior tibial osteophytes and talar osteophytes were statistically significantly higher in the group with anterior impingement than in the control group. Conventional MR imaging was found to be insensitive for the diagnosis of syndesmotic soft tissue impingement of the ankle. Fibrovascular scar tissue distinct from syndesmotic ligaments is suggestive for the diagnosis of soft tissue impingement, but the reliability of these findings is still questionable. Electronic Publication     

Treatment of anterolateral impingements of the ankle joint by arthroscopy

Impingement syndromes of the ankle joint are among the most common intraarticular ankle lesions. Soft tissue impingement lesions of the ankle usually occur as a result of synovial, or capsular irritation secondary to traumatic injuries, usually ankle sprains, leading to chronic ankle pain. The aim of this prospective study was to evaluate arthroscopic debridement of an anterolateral soft tissue impingement of the ankle. During the period between October 2000 and February 2004, 23 patients with residual complaints after an ankle sprain were diagnosed as anterolateral impingement of the ankle, and were treated by arthroscopic debridement. At a minimum of 6 months follow up, patients were asked to complete an American orthopaedic foot and ankle society (AOFAS) ankle and hind foot score. The average follow-up was 25 months (range 12–38). The average pre-operative patient assessed AOFAS score was 34 (range 4–57). At the end of follow-up the mean AOFAS score was 89 (range 60–100). In terms of patient satisfaction 22 patients said they would accept the same arthroscopic procedure again for the same complaints. At the end of follow-up, 7 patients had excellent results, and 14 patients had good results while two patients had fair results. We believe that arthroscopic debridement of the anterolateral impingement soft tissues are a good, and effective method of treatment.     

MRI of lateral hindfoot impingement

Lateral hindfoot impingement (LHI) is a subtype of ankle impingement syndrome with classic MRI findings. Biomechanically, LHI is the sequela of lateral transfer of weight bearing from the central talar dome to the lateral talus and fibula. The transfer occurs due to collapse of the medial arch of the foot, most commonly from posterior tibial tendon (PTT) and spring ligament (SL) insufficiency. Clinical features include lateral hindfoot pain, deformity, and overpronation on gait analysis. MRI changes continuously reflect the altered biomechanics as the syndrome progresses over time, including typical and often sequential changes of PTT and SL failure, increasing heel valgus, talocalcaneal and subfibular impingement, and finally lateral soft tissue entrapment. In addition to diagnosis, MRI is a useful adjunct to plan surgical treatment.

Lateral hindfoot impingement (LHI) is a subtype of ankle impingement with classic MRI findings (1). Biomechanically, LHI is the sequela of lateral transfer of weight bearing from the central talar dome to the lateral talus and fibula.Primary LHI is rare and may occur due to an accessory anterolateral talar facet (2). Although a common accessory articulation; it can cause impingement in the occasional obese patient with subtalar eversions.Secondary LHI is common and consequent to posterior tibial tendon (PTT) dysfunction, collapse of the medial longitudinal arch and lateral weight transfer (1). Less frequent causes of secondary LHI are neuropathic, inflammatory and degenerative arthritis of the subtalar, and transverse talar articulations. Tarsal coalitions and malunited fractures of the calcaneum are also among the uncommon causes of secondary LHI (3, 4).MRI is useful in the diagnosis of LHI as there are several causes of lateral hindfoot pain other than impingement with overlapping clinical features. Conversely, MRI morphology and signal alteration of LHI are distinct. The multiplanar capability of MRI allows accurate assessment of the complex biomechanics and corresponding joint malalignments of LHI syndrome. Moreover, inherent sensitivity to marrow signal allows depiction of marrow edema in characteristic locations of osseous impingement. Finally, high contrast resolution permits depiction of endstage soft tissue entrapments of small ligaments and nerves (5).In this pictorial essay, common etiologies and the resulting wide spectrum of bone and soft tissue abnormalities of LHI seen on MRI are demonstrated. The accompanying diagrams depict sequential derangements in alignment that lead to typical MRI appearances.     

MRI symptomology in reflex sympathetic dystrophy of the foot]

PURPOSE: To describe the MRI findings of reflex sympathetic dystrophy of the foot and ankle. METHODS: Retrospective study of 50 patients with reflex sympathetic dystrophy of the foot (5 with the cold form, and 45 with the warm form) diagnosed based on clinical and scintigraphic findings. All patients underwent MR imaging. The MRI findings were correlated with the clinical and scintigraphic findings. RESULTS: Patients with the cold form of reflex sympathetic dystrophy had no abnormality of signal at MR imaging. All patients with the warm from of reflex sympathetic dystrophy showed periarticular marrow edema at MR, typically involving more than one bone (mean of 4). Other findings were inconstant: soft tissue edema, joint effusion, and rarely, subchondral band of low T1W signal intensity of unclear etiology. CONCLUSION: MR imaging, including fat-suppressed T2W or STIR images and noncontrast T1W images, is helpful in patients with the warm or acute form of reflex sympathetic dystrophy of the foot. In patients with the cold form, MR imaging is helpful to exclude another underlying etiology for the symptoms and identify patients with the warm form of the process.     

Chronic tibiofibular syndesmosis injury of ankle: evaluation with contrast-enhanced fat-suppressed 3D fast spoiled gradient-recalled acquisition in the steady state MR imaging

PURPOSE: To retrospectively determine the accuracy of coronal contrast material-enhanced fat-suppressed three-dimensional (3D) fast spoiled gradient-recalled acquisition in the steady state (SPGR) magnetic resonance (MR) imaging, as compared with that of routine transverse MR imaging, in the assessment of distal tibiofibular syndesmosis injury, with arthroscopy as the reference standard. MATERIALS AND METHODS: The review board of the College of Medicine in Yonsei University approved this study; informed consent was waived. The study group comprised 45 patients (26 men, 19 women; mean age, 32.1 years; range, 18-58 years) with a chronic ankle injury who had undergone MR imaging and arthroscopic surgery. Three independent readers retrospectively reviewed the two sets of MR images (one set of gadolinium-enhanced 3D fast SPGR images and one set of routine T1-, T2-, and intermediate-weighted images). Scores from 1 to 5 in increasing order of the probability of injury were assigned to both sets. Arthroscopy was the reference standard. Syndesmotic recess height was measured on contrast-enhanced images. The two sets of images were compared for diagnostic performance with receiver operating characteristic (ROC) analysis. Dissection and histologic examination of six cadaveric ankles was performed to assess the syndesmotic area and ascertain the enhancing structure at MR imaging. RESULTS: At arthroscopy, syndesmotic injury was found in 24 ankles but not in 21 ankles. Areas under the ROC curve were significantly higher for the contrast-enhanced images (P<.05). The contrast-enhanced set showed higher accuracy, sensitivity, and specificity compared with the routine set for the assessment of syndesmosis injury. Mean syndesmotic recess height was significantly greater (P<.05) in patients with syndesmotic injury. Dissection and histologic examination revealed a highly vascular synovial fold in the syndesmotic area that is expected to enhance at MR imaging. CONCLUSION: In the assessment of chronic syndesmosis injury, coronal gadolinium-enhanced fat-suppressed 3D fast SPGR MR images were more sensitive, specific, and accurate than routine MR images.     

足踝部X线表现阴性痛风性关节炎的CT与MRI表现对比研究

目的:对足踝部X线平片表现阴性痛风患者的CT和MRI表现进行对比研究,评估其隐匿性骨质破坏及其他影像学表现。方法:收集于我院就诊的36例X线平片阴性痛风患者,于2周内均行CT与MRI平扫,分析骨质破坏、关节内和/(或)周围痛风石、软组织肿胀、关节腔积液、滑膜增厚和骨髓水肿等征象。结果:36例CT平扫可见骨质破坏23例,MRI可见13例,二者差异有统计学意义(P=0.002)。CT平扫可见关节内和/(或)周围痛风石23例,MRI可见27例,二者差异无统计学意义(P=0.289);其中21例CT、MRI均见痛风石表现,6例仅MRI可见,2例仅CT可见。CT与MRI平扫分别有11例和15例可见关节腔积液表现,二者差异无统计学意义(P=0.125)。2种检查均见软组织肿胀24例,差异无统计学意义(P=1.000)。另外,36例的MRI平扫中,4例可见滑膜增厚,30例见骨髓水肿表现。结论:CT与MRI平扫可显示X线平片无法显示的隐匿性骨质破坏及微小痛风石,CT平扫对于早期骨质破坏的显示优于MRI,但MRI可提供更多影像信息。对于足踝部X线表现阴性痛风性关节炎,CT与MRI相结合为最佳检查手段。     

Imaging features suggestive of a conjoined nerve root on routine axial MRI

Objective The purpose of our study is to evaluate imaging features suggestive of a conjoined nerve root on routine axial MRI. Methods Two radiologists and two surgeons retrospectively reviewed the MRI of three cases in which a conjoined nerve root was discovered during operation and found three suggestive signs on routine axial MR images: “corner” (asymmetric morphology of the anterolateral corner of the dural sac), “fat crescent” (intervening extradural fat between the asymmetric dura and the nerve root), and “parallel” signs (visualization of the entire parallel course of the nerve root at the disc level). Two radiologists prospectively found these signs during routine MRI interpretation sessions over a period of 6 months. If one or a combination of signs were noted on axial MR images, contiguous axial scans were additionally obtained. Three cases that were previously found during operations were also included. Prevalence and confidence scores for each sign were assessed on axial T1- and T2-weighted images. Results Twelve patients showed one or a combination of the three signs, 9 had contiguous axial MR scans. Five cases were confirmed by operation. The prevalence of the corner, fat crescent, and parallel signs were 12 out of 12 (100%), 6 out of 12 (50%), and 8 out of 12 (67.7%) on axial T1-weighted images. The overall diagnostic confidence was higher on T1- than on T2-weighted images (P < 0.05). Conclusion On routine axial L-spine MRI, corner, fat crescent, and parallel signs are suggestive of and assist in the recognition of a conjoined nerve root.     

The distal fascicle of the anterior inferior tibiofibular ligament as a cause of tibiotalar impingement syndrome: a current concepts review

Impingement syndromes of the ankle involve either osseous or soft tissue impingement and can be anterior, anterolateral, or posterior. Ankle impingement syndromes are painful conditions caused by the friction of joint tissues, which are both the cause and the effect of altered joint biomechanics. The distal fascicle of the anterior inferior tibiofibular ligament (AITFL) is possible cause of anterior impingement. The objective of this article was to review the literature concerning the anatomy, pathogenesis, symptoms and treatment of the AITFL impingement and finally to formulate treatment recommendations. The AITFL starts from the distal tibia, 5 mm in average above the articular surface, and descends obliquely between the adjacent margins of the tibia and fibula, anterior to the syndesmosis to the anterior aspect of the lateral malleolus. The incidence of the accessory fascicle differs very widely in the several studies. The presence of the distal fascicle of the AITFL and also the contact with the anterolateral talus is probably a normal finding. It may become pathological, due to anatomical variations and/or anterolateral instability of the ankle resulting from an anterior talofibular ligament injury. When observed during an ankle arthroscopy, the surgeon should look for the criteria described to decide whether it is pathological and considering resection of the distal fascicle. The presence of the AITFL and the contact with the talus is a normal finding. An impingement of the AITFL can result from an anatomical variant or anteroposterior instability of the ankle. The diagnosis of ligamentous impingement in the anterior aspect of the ankle should be considered in patients who have chronic ankle pain in the anterolateral aspect of the ankle after an inversion injury and have a stable ankle, normal plain radiographs, and isolated point tenderness on the anterolateral aspect of the talar dome and in the anteroinferior tibiofibular ligament. The impingement syndrome can be treated arthroscopically.     

Cartilaginous endplates of the spine: MRI with anatomic correlation in cadavers

PURPOSE: The purpose of this work was to describe the MR appearance of cartilaginous endplates (CEPs) with close anatomic correlation in cadavers derived from elderly subjects. METHOD: High-resolution MRI was performed on five cadaveric lumbar spines, and a total of 48 CEPs were studied with T1-weighted spin echo, T2-weighted fast spin echo, and fat-suppressed 3D spoiled GRASS gradient echo (SPGR) MR images. All specimens underwent anatomic sectioning, and gross anatomic findings were correlated with those of MRI. RESULTS: Conventional MR images allowed gross morphologic evaluation of the integrity of the CEPs and demonstrated cartilaginous nodes. In all specimens, fat-suppressed 3D-SPGR images invariably improved visualization of the fine anatomic structures at the diskovertebral junction (p < 0.01). Various morphologic abnormalities of the CEPs demonstrated on MR images, including thinning, irregularity, erosions, cartilaginous defects, and Schmorl nodes, were confirmed on anatomic inspection. CONCLUSION: Results in our study indicate that MRI may delineate the normal anatomy of CEPs and demonstrate morphologic changes occurring at the diskovertebral junction. Dedicated high-resolution technique and fat-suppressed 3D-SPGR images may significantly improve the diagnostic capabilities of MRI of this particular anatomic region.     

Anterolateral ankle impingement: mr arthrographic assessment of the anterolateral recess

PURPOSE: To determine the accuracy of magnetic resonance (MR) arthrography in assessing the anterolateral recess of the ankle. MATERIALS AND METHODS: Thirty-two patients with chronic ankle pain prospectively underwent gadolinium-enhanced MR arthrography of the tibiotalar joint. All underwent clinical examination and were included if anterolateral impingement (n = 13) or a control condition (n = 19; suspected osteochondral defect, intraarticular bodies, instability, osteoarthritis) was diagnosed. MR imaging included transverse and coronal T1-weighted and sagittal T2-weighted imaging sequences. Images were prospectively analyzed by two readers blinded to the clinical diagnosis. The anterolateral gutter contour was assessed. MR arthrographic findings were correlated with subsequent arthroscopic appearances. RESULTS: MR arthrographic assessment of the anterolateral soft tissues had an accuracy of 97%, sensitivity of 96%, specificity of 100%, negative predictive value of 89%, and positive predictive value of 100%. Accuracy was 100% with clinical anterolateral impingement, with an arthroscopically confirmed abnormality in 12 cases and a normal appearance in one. Anterolateral soft-tissue thickening was identified at MR arthrography in 11 control cases, with arthroscopic confirmation in all. The remaining cases had normal appearances, with an arthroscopic soft-tissue abnormality in one case and a normal appearance in seven. CONCLUSION: MR arthrography of the tibiotalar joint is accurate in assessing the anterolateral recess of the ankle.     

Malignant hepatic tumor detection with ferumoxide‐enhanced magnetic resonance imaging: Is chemical‐shift‐selective fat suppression necessary for fast spin‐echo sequence?

PURPOSE: To determine whether chemical-shift-selective (CSS) fat suppression is necessary for ferumoxide-enhanced T2-weighted fast spin-echo (FSE) imaging in the detection of malignant hepatic tumors. MATERIALS AND METHODS: Ferumoxide-enhanced magnetic resonance (MR) images obtained in 38 patients with surgically confirmed 61 malignant hepatic tumors (36 hepatocellular carcinomas (HCCs), 25 metastases) were retrospectively reviewed by three independent readers. Three sequences of MR images with CSS fat-suppressed T2-weighted FSE, non-fat-suppressed T2-weighted FSE, and T2*-weighted gradient-recalled-echo (GRE) sequences were randomly reviewed on a segment-by-segment basis in a blind fashion. Observer performance was tested using the McNemar's test and receiver-operating-characteristic (ROC) analysis for the clustered data. Lesion-to-liver contrast-to-noise ratio (C/N) was also assessed. RESULTS: The mean C/N with the CSS fat-suppressed FSE sequence was highest in HCCs, metastases, and tumors overall. Sensitivity was highest with the CSS fat-suppressed FSE sequence in HCC, was highest with the non-fat-suppressed FSE sequence in metastases, and was comparable in tumors overall. Specificity was comparable between the sequences. The area under ROC curve (Az) value was greatest with the CSS fat-suppressed FSE sequence in HCCs, was greatest with the non-fat- suppressed FSE sequence in metastases, and was comparable in tumors overall. The sensitivities and Az values were lower with the GRE sequence than the FSE sequence. CONCLUSION: The CSS fat-suppressed FSE sequence was superior to the GRE sequence in the detection of HCCs, but the non-fat-suppressed FSE sequence was comparable to the GRE sequence. The non-fat-suppressed FSE sequence was superior to the CSS fat-suppressed FSE and GRE sequences in the detection of metastases. Optimal FSE imaging with CSS fat suppression or without aiming for the detection of HCCs or metastases, respectively, outperforms GRE imaging in ferumoxide-enhanced MRI.     

Small bowel neoplastic disease: Demonstration by MRI

This study demonstrates the appearance of small bowel tumors on MR images. Sixteen patients with tumors involving small bowel were studied by MRI. All tumors were proven with histopathology. Eleven patients had primary tumors of the small bowel, which included the following: four carcinoid tumors, three adenocarcinomas, two lymphomas, one leiomyosarcoma, and one leiomyoma. Five patients had recurrent or metastatic disease to small bowel: two patients had colon cancer, one patient had pancreatic cancer, one patient had uterine leiomyosarcoma, and one patient had chloroma (leukemia). MR examination included breath-hold T1-weighted spoiled gradient echo (all patients), immediate postgadolinium-spoiled gradient echo (10 patients), and 2 to 4 minutes postgadolinium T1-weighted, fat-suppressed images (all patients). Tumor size, local extent, signal intensity, and enhancement features of tumor and adjacent tissue were determined. Tumor ranged in diameter from 1 to 9 cm (mean, 4.0 cm). Tumors had similar signal intensity to normal small bowel on precontrast images. Fourteen malignant tumors showed heterogeneous enhancement greater than adjacent bowel on gadolinium-enhanced images. Tumor local extent was best shown on precontrast-spoiled gradient-echo images and postgadolinium T1-weighted fat-suppressed images. Image quality was most consistent on breath-hold images. The results of this study show that small bowel tumors are demonstrable on MR images. Precontrast breath-hold T1-weighted spoiled gradient-echo images and gadolinium-enhanced fat suppressed images demonstrate tumor extent most reliably.     

Bowel disease: prospective comparison of CT and 1.5-T pre- and postcontrast MR imaging with T1-weighted fat-suppressed and breath-hold FLASH sequences.

The potential of new high-field-strength magnetic resonance (MR) imaging sequences to evaluate bowel disease was investigated and compared with computed tomographic (CT) studies. Thirty-two patients were studied, 14 with known or suspected gastrointestinal tumors and 18 with known or suspected bowel inflammatory conditions. T1-weighted fat-suppressed spin-echo and breath-hold FLASH (fast low-angle shot) images were obtained before and after intravenous injection of 0.1 mmol/kg gadopentetate dimeglumine. Pathologic confirmation was obtained by biopsy (n = 18), surgical excision (n = 8), or endoscopy (n = 6). CT and MR images were analyzed separately in a prospective fashion and reviewed by consensus. Information from CT and MR images was comparable in cases of confirmed bowel neoplasia. CT scans had better spatial resolution, while fat-suppressed gadolinium-enhanced MR images had better contrast resolution. In the 18 cases of bowel inflammation, CT scans showed concentric wall thickening in 16, while MR images showed concentric wall thickening in 14 and increased contrast enhancement in 17. Contrast enhancement was better appreciated on fat-suppressed images than on FLASH images. The results suggest that MR imaging may play a role in the evaluation of bowel disease.     

Evaluation of locally recurrent pelvic malignancy: performance of T2- and diffusion-weighted MRI with image fusion

PURPOSE: To evaluate the performance of T2- and diffusion-weighted magnetic resonance imaging (MRI) with image fusion for detection of locally recurrent pelvic malignancy. MATERIALS AND METHODS: The study group consisted of 28 patients (27 female, 1 male) who underwent pelvic MRI at 1.5 T after treatment of pelvic malignancy. MR images were reviewed independently by three blinded readers. The performance of the four sequences for detecting local recurrence was evaluated using receiver operating characteristic analysis: T2-weighted fast spin-echo (FSE), diffusion-weighted echo-planar imaging (DWI), dynamic contrast-enhanced (DCE) fat-suppressed T1-weighted spoiled gradient echo (SPGR), and T2-DWI with image fusion, the latter created using OsiriX Medical Imaging Software. RESULTS: Local recurrence was confirmed at biopsy in 16 patients. Twelve patients showed no evidence of recurrence on two consecutive MRI studies. The Az value for T2-DWI with image fusion (0.949) was statistically greater than that for T2-weighted FSE (0.849) (P<0.05). The sensitivity and specificity was 87.5% and 47.2%, respectively, for T2-weighted FSE, 100.0% and 50.0% for DWI, 95.8% and 58.3% for DCE fat-suppressed T1-weighted SPGR, and 93.8% and 72.2% for T2-DWI with image fusion. CONCLUSION: For depicting locally recurrent pelvic malignancy, T2-DWI with image fusion outperforms standard T2-weighted FSE and DWI and is comparable to DCE fat-suppressed T1-weighted SPGR.     

Shoulder MRI after impingement test injection

Objective. To determine how long injected fluid from an impingement test remains in the bursa or adjacent soft tissues after an injection. Design and patients. Six patients prospectively underwent MRI of the shoulder immediately before and after an impingement test injection, and at 3 days, 2 weeks and 4 weeks later. MR images were evaluated and graded for fluid distribution within the bursa and adjacent soft tissues. The rotator cuff was evaluated for signal abnormalities related to the injection. Results and conclusion. Three days after the injection, the soft tissue fluid had returned to pre-injection levels or less in five of the six patients. No patients showed rotator cuff signal abnormalities related to the impingement test injection. We recommend a delay of 3 days before a shoulder MR examination after an injection has been performed, to avoid misinterpretations.     

An approach for three-dimensional visualization using high-resolution MRI of the temporomandibular joint

OBJECTIVES: To visualize the temporomandibular joint (TMJ) and the surrounding tissues in detail utilizing high-resolution MR images for the diagnosis of soft- and hard-tissue abnormalities. Clinically routine MR slices are processed by tissue segmentation and three-dimensional (3D) reconstruction and viewed with visualization software. MATERIALS AND METHODS: A 1.5 T MRI system was used. The double-echo procedure for taking oblique sagittal images was applied to obtain both proton density-weighted (PDW) and T2 weighted (T2W) images simultaneously, with separate examinations in both open and closed mouth positions. Diagnosis of the abnormality in the placement and morphology of articular discs and the joint effusion status is usually performed using multiple MRI slices. Clinically routine continuous MR slices were processed by segmentation, reconstruction and visualization algorithms, and the mandibular condyle, fossa, articular disc and other intra-articular tissues were visualized on the 3D and two-dimensional (2D)-3D fusion images. RESULTS: In a clinical case, the anterior disc displacement without reduction, with mouth open and closed, was clearly depicted in the 3D images. Also 2D-3D superposed images with changeable tissue transparency successfully depicted the stereoscopic TMJ morphology in three dimensions. DISCUSSION AND CONCLUSION: High-resolution PDW- and T2W MR images could be processed by tissue segmentation and 3D-reconstruction procedures, and the resultant images showed the anatomical details in an easily recognizable way. By the simultaneous visualization of both bony surfaces and soft tissues, disc displacement and deformity can be recognized in a 3D context. The additional superposition of the 3D visualization with the original 2D MR slices allows for a combination with conventional diagnostics.