Projections of the ventral tegmental area of the midbrain, the substantia nigra, and the amygdaloid body in different parts of the putamen in the dog

INTRODUCTION: We investigated the accuracy of endorectal coil Magnetic Resonance Imaging (MRI) and Fast Spin Echo (FSE) technique in staging prostate cancer. MATERIAL AND METHODS: MRI was performed in 70 patients with biopsy proved prostatic cancer. A total of 33 patients subsequently underwent radical prostatectomy. T2-weighted FSE sequences (TR 3400-4100, TE 120, Echo train length 13) were acquired in all patients. Axial, sagittal and coronal 4-5 mm images were obtained with 13-14 cm field of view and 256 x 256 matrix. Additional T1-weighted spin echo images were acquired in 9 patients. Lesion staging on MR images was performed according to the American Urological System. MR data were compared with the pathologic findings of whole-mount sections of the surgical specimens. RESULTS: Overall accuracy for endorectal coil MR imaging was 60%; ten cases were underestimated and 3 cases were overestimated. The sensitivity and the specificity of endorectal coil MRI in diagnosing capsular penetration were 77% and 81%, respectively. Seminal vesicle invasion was detected with 87% sensitivity and 96% specificity. CONCLUSIONS: Endorectal coil MRI provides a more accurate preoperative local staging.     

Few microorganisms associated with bacterial vaginosis may constitute the pathologic core: a population-based microbiologic study among 3596 pregnant women

OBJECTIVE: To evaluate if pelvic magnetic resonance imaging (MRI) is reliable for differentiating leiomyoma subtypes. DESIGN: Prospective study. SETTING: Academic center. PATIENT(S): Forty-five patients underwent MRI before surgery for leiomyomata. INTERVENTION(S): One radiologist blinded to patient history and histologic diagnosis recorded the MRI characteristics and classification of the largest leiomyoma. MAIN OUTCOME MEASURE(S): Comparison of MRI and histologic diagnoses. RESULT(S): Leiomyoma subtypes were diagnosed accurately by MRI in 69% of cases. Magnetic resonance imaging had a 95% sensitivity and 72% specificity for diagnosing an uncomplicated leiomyoma and a 10% sensitivity and 100% specificity for a cellular leiomyoma. For cystic leiomyomata, the sensitivity was 80% and specificity was 98%, and for hemorrhagic leiomyomata, 100% and 86%, respectively. Magnetic resonance imaging correctly diagnosed all malignant tumors and did not incorrectly diagnose a leiomyoma as a leiomyosarcoma in any case. Ill-defined MRI margins were significantly more likely to be leiomyosarcoma, whereas well-defined margins were characteristic of benign lesions. Hemorrhagic leiomyomata were significantly more likely to be hyperintense on T1-weighted images than other subtypes. CONCLUSION(S): Although MRI is only fairly accurate in differentiating the subtypes of benign uterine smooth muscle tumors, signal intensities and margin characteristics are useful to distinguish accurately benign from malignant tumors.     

Transdermal oestrogen reduces daytime blood pressure in hypertensive women [see comment

A complex system of connective-tissue septa within the orbit has previously been described in serial histologic sections. The present study describes the anatomy of the orbital connective tissue system on high-resolution magnetic resonance (MR) images in vivo. Five volunteers aged 26 to 35 year underwent magnetic resonance imaging of the orbit on a 1 Tesla unit (Impact, Siemens, Germany). T1-weighted coronal images were obtained using a surface coil. Anatomical structures on the MR images were identified by comparison with corresponding histologic sections. On MR images of the anterior orbit, the levator aponeurosis, Lockwood ligament, transverse intermuscular ligament, common sheath, check ligaments, Tenon capsule, intermuscular septa, and palpebral ligaments can be seen. In the mid- and posterior orbit, the intermuscular orbital septa, especially the superolateral septum, the superior ophthalmic vein hammock, and septa of the radial connective tissue system are visualized. High-resolution magnetic resonance imaging is capable of delineating the major septa of the orbital connective tissue system.     

Nitric oxide superoxide and peroxynitrite modulate osteoclast activity

PURPOSE: To assess whether magnetic resonance (MR) spectroscopic imaging with MR imaging can improve prostate cancer localization in postbiopsy hemorrhage cases. MATERIALS AND METHODS: Records of 175 patients with prostate cancer were retrospectively reviewed; 42 patients (135 hemorrhagic sites) had spatially correlated biopsy data. Patients underwent both phased-array coil-endorectal coil MR imaging and three-dimensional MR spectroscopic imaging within 180 days after transrectal ultrasound (US)-guided biopsy. High-signal-intensity hemorrhage on T1-weighted images and corresponding high- or low-signal-intensity areas on T2-weighted images and the metabolic ratio (choline + creatine)/citrate were recorded. Cancer was identified as a low-signal-intensity area at T2-weighted MR imaging or a metabolite ratio greater than 3 standard deviations above normal at MR spectroscopic imaging. MR imaging, spectroscopic, and biopsy findings were compared. RESULTS: Forty-nine patients had postbiopsy hemorrhage. On T2-weighted images, a higher (P < .01) percentage of hemorrhagic sites demonstrated low signal intensity (80% [108 of 135 sites]), which is similar to the signal intensity seen with cancer. The addition of MR spectroscopic imaging to MR imaging resulted in a significant increase (P < .01) in the accuracy (52% to 75%) and specificity (26% to 66%) of tumor detection. CONCLUSION: The addition of MR spectroscopic imaging to MR imaging significantly improves the ability to determine the presence of prostate cancer and spatial extent when postbiopsy changes hinder interpretation with MR imaging alone.     

Antimyosin scintigraphy compared with magnetic resonance imaging in inflammatory myopathies

OBJECTIVE: To compare indium In 111 altumomab pentetate-labeled antimyosin scintigraphy with magnetic resonance imaging (MRI) in the diagnosis and follow-up of patients with myositis. DESIGN AND METHODS: Sixteen patients with polymyositis and 1 patient with dermatomyositis, all verified with biopsy samples, were examined during diagnostic evaluation with antimyosin antibody scintigraphy and low-field MRI of the thighs and calves using T1- and T2-weighted sequences. Both examinations were repeated 6 to 22 months after therapeutic intervention with antiinflammatory drugs. The performance of the 2 methods for the assessment of the severity of muscle inflammation was evaluated using comparison with clinical examination and the serum creatine kinase level. RESULTS: At diagnosis all patients had increased uptake of antimyosin antibody in the thighs and/or calves. In T2-weighted MRI images, increased signal intensity changes reflecting intramuscular edema and inflammation were seen in all patients in at least 1 muscle group in the thighs or calves. After anti-inflammatory drug therapy, the mean uptake of antibody and the mean signal intensity changes in T2-weighted MRI had decreased. However, in T1-weighted MRI the signal intensity changes reflecting intramuscular fatty degeneration were more pronounced in the follow-up study. The level of serum creatine kinase had decreased markedly by the second examination except in 1 patient who also had more accumulation of antibody in the calves after than before treatment. The clinical condition improved in 8 patients and remained unchanged in 9 patients. CONCLUSIONS: Antimyosin scintigraphy and T2-weighted MRI are feasible tools for the detection and follow-up of lesions in patients with myositis. Scintigraphy findings correlate with serum creatine kinase activity and seem to reflect disease activity better than T2-weighted MRI changes, whereas secondary degenerative intramuscular lesions are only detectable using T1-weighted MRI.     

Chronic pulmonary histoplasmosis in Brazil: report of two cases with cavitation diagnosed by transthoracic needle biopsy

OBJECTIVE: To compare fat-suppressed fast spin-echo (FSE) T2-weighted images with gradient-recalled echo (GRE) T2*-weighted images in the evaluation of anteroinferior labral tears. DESIGN: MR images were retrospectively reviewed by two radiologists masked to the history and arthroscopic findings. They separately interpreted the anteroinferior labrum as torn or intact, first on one pulse sequence and then, 4 weeks later, on the other sequence. The MR interpretations were correlated with the arthroscopic findings. PATIENTS: Nine patients with anteroinferior labral tears, and nine similarly-aged patients with normal, labra were studied. RESULTS AND CONCLUSIONS: Observer 1 had a sensitivity of 0.56 on the GRE images and 0.67 on the FSE images (P > 0.5), with a specificity of 1.0 for both sequences. Observer 2 had a sensitivity of 0.78 and a specificity of 0.89 for both sequences. In this small study there is no significant difference between GRE and fat-suppressed FSE images in their ability to diagnose anteroinferior labral tears. When evaluating the labrum with conventional MRI, axial fat-suppressed FSE T2-weighted images can be used in place of GRE images without a loss of accuracy.     

Normal variants and pitfalls in magnetic resonance imaging of the ankle and foot

Distinction of normal from disease is one of the principal tenets in magnetic resonance imaging (MRI) interpretation of the foot and ankle. Therefore, familiarity with normal anatomic variants and pitfalls in the foot and ankle is crucial for accurate diagnostic analysis of MR images. This article will focus on outlining variants and MRI interpretation pitfalls of the tendons, muscles, bones, ligaments, and other miscellaneous structures of the foot and ankle.     

Stromal invasion by carcinoma of the cervix: assessment with dynamic MR imaging

OBJECTIVE: The purpose of this study was to evaluate dynamic MR imaging in assessing the depth of stromal invasion by carcinoma of the cervix and to compare dynamic MR imaging with T2-weighted and contrast-enhanced T1-weighted MR imaging. SUBJECTS AND METHODS: Forty-one patients with carcinoma that was clinically considered to be confined to the cervix were examined with T2-weighted, dynamic, and contrast-enhanced T1-weighted MR imaging before surgery. We evaluated enhancement patterns of the cervix and tumor and assessed the degree of stromal invasion with MR imaging. The degree of stromal invasion was divided into two groups: superficial disease (no stromal invasion or invasion of < or = 3 mm) and deep invasion (> 3 mm of stromal invasion). Then we compared these MR findings with histologic results for the depth of stromal invasion. RESULTS: With dynamic MR imaging, cervical carcinoma with deep invasion was seen as a focal enhanced area in the early dynamic phase. The cervical epithelium and stroma enhanced less vividly. In distinguishing deep invasion from superficial disease, we found the accuracy of T2-weighted MR images, dynamic MR images, and contrast-enhanced T1-weighted MR images to be 76%, 98%, and 63%, respectively. In particular, the detectability of 3.1-5.0 mm of stromal invasion with dynamic MR images was significantly higher than that with the other techniques: with T2-weighted MR images, we saw 3.1-5.0 mm of stromal invasion in 23% of patients; with dynamic MR images, in 92%; and with contrast-enhanced T1-weighted MR images, in none. Superficial disease was not revealed with any of the three MR techniques. CONCLUSION: We believe that dynamic MR imaging is superior to T2-weighted MR imaging and contrast-enhanced T1-weighted MR imaging when assessing the depth of invasion of cervical carcinoma.     

Only visual impressions are almost always present in long-term memories, and reported completeness, accuracy, and verbalizability of recollections increase with age

PURPOSE: To stage advanced cervical carcinoma with conventional or pharmacokinetic magnetic resonance (MR) imaging by correlating imaging findings with whole-mount specimens and histopathologic findings. MATERIALS AND METHODS: Twenty-six adult patients with primary cervical cancer (stages IIB-IVA) underwent T2-weighted turbo spin-echo (SE) MR imaging; gadolinium-enhanced, T1-weighted SE MR imaging; and gadolinium-enhanced, saturation-recovery, turbo fast low-angle shot MR imaging. All imaging findings were correlated with the whole-mount specimens and histopathologic findings. Signal intensity changes versus time were analyzed by using a pharmacokinetic model and parameter values displayed as a color-coded overlay. RESULTS: Histopathologic stages were IIB (n = 9), IIIB (n = 1), and IVA (n = 16). The overall accuracy for tumor staging was 73% for T2-weighted, 81% for T1-weighted, and 92% for pharmacokinetic MR imaging. Pharmacokinetic MR imaging was accurate (90%) in the diagnosis of tumor extension into the bladder and/or rectal wall but inaccurate (69%) in that of parametrial invasion. T2-weighted images were most accurate (86%) in the assessment of parametrial tumor extension but less accurate (69%) in that of bladder or rectal invasion. CONCLUSION: T2-weighted turbo SE images are still superior to contract medium-enhanced T1-weighted SE or pharmacokinetic MR images in the diagnosis of parametrial infiltration by uterine cervical carcinoma. However, pharmacokinetic MR imaging is a promising method for demonstrating and staging IVA disease.     

Detection of avian leukosis virus subgroup J using the polymerase chain reaction

PURPOSE: To compare neutral, external rotation, and abduction external rotation positions of the glenohumeral joint during magnetic resonance (MR) arthrography in the assessment of the joint capsule, biceps-labral complex, and glenohumeral ligaments. MATERIALS AND METHODS: MR imaging with intraarticular administration of gadopentetate dimeglumine was performed in 10 adult cadaveric glenohumeral joints. Fat-suppressed oblique coronal, oblique sagittal, and axial. T1-weighted spin-echo imaging and axial three-dimensional spoiled gradient-recalled imaging were performed with each shoulder in the neutral, external rotation, and abduction external rotation positions. Shoulders were sectioned in the planes that yielded optimal MR images. Anatomic and MR imaging findings were correlated. RESULTS: The biceps-labral complex was best visualized on oblique coronal and axial images obtained in external rotation. Oblique axial abduction external rotation imaging best delineated the inferior glenohumeral ligament but did not improve assessment of the superior and middle glenohumeral ligaments in comparison with findings in neutral and external rotation. CONCLUSION: Although MR arthrography of the glenohumeral joint clearly delineates the biceps-labral complex and glenohumeral ligaments, external rotation of the shoulder optimizes visualization of the former structures. Abduction external rotation is the best position for evaluation of the inferior glenohumeral ligament and anterior capsular attachment.     

The growth inhibitory effect of N1,N12-bis(ethyl)spermine in small cell lung cancer cells is maintained in cells expressing the c-myc and Ha-ras oncogenes

OBJECTIVE: The purpose of this study was to assess the diagnostic role of MR arthrography in patients with tendinopathy or rupture of the long biceps tendon. MATERIALS AND METHODS: MR arthrograms of 42 consecutive patients with arthroscopic or surgical confirmation of diagnosis (16 normal biceps tendons, 19 with tendinopathy, and seven with ruptures) were analyzed independently by two radiologists. Visibility of the biceps tendon, caliber changes, contour irregularities, and signal intensities were assessed separately in the parasagittal and axial planes. In addition, the two radiologists made an overall evaluation of abnormalities of the biceps tendon using both MR imaging planes. RESULTS: The most reliable MR findings for tendinopathy were caliber changes (sensitivity was 59% for observer 1 and 82% for observer 2; specificity was 88% and 64%, respectively) and signal abnormalities (sensitivity, 77% and 88%, respectively; specificity, 75% and 43%, respectively) in the parasagittal plane. Absence of visualization of the tendon in the parasagittal plane was a reliable sign for rupture (sensitivity, 86% and 86%, respectively; specificity, 94% and 87%, respectively). The overall sensitivity for detecting abnormalities (tendinopathy or rupture) was 92% for observer 1 and 89% for observer 2. Specificity was 56% and 81%, respectively. CONCLUSION: MR findings of tendinopathy and rupture of the biceps tendon are subtle. However, the combination of several MR criteria in two imaging planes makes a reasonably accurate diagnosis possible. The biceps tendon should not only be assessed in the bicipital sulcus on axial images but also on parasagittal images.     

Fast fluid-attenuated inversion recovery (FLAIR) compared with T2-weighted spin-echo in the magnetic resonance diagnosis of mesial temporal sclerosis

RATIONALE AND OBJECTIVES: The authors compare coronal fast fluid-attenuated inversion recovery (FLAIR) with coronal T2-weighted spin-echo (SE) magnetic resonance (MR) techniques in the diagnosis of mesial temporal sclerosis (MTS). METHODS: In this prospective study, the authors assessed MR scans of 30 patients with drug-resistant temporal lobe epilepsy (based on clinical symptomatology and electroencephalographic registrations) with MR features suggestive of MTS. MR scans of age-, sex-, and scanner-matched patients, referred for MR assessment of white matter disease, without a history of epilepsy and with no visible abnormalities on MR, were used as controls. In 16 patients the MR diagnosis was confirmed by histologic abnormalities consistent with MTS. Coronal T2 SE and FLAIR images of patients and controls were presented to two experienced radiologists in random order for independent blinded review. Hippocampal and associated extrahippocampal temporal lobe abnormalities were used for the diagnosis of MTS. RESULTS: The sensitivity of observer A was 97% for the T2 SE sequence and 100% for the FLAIR; the specificity of observer A for both techniques was 100%. The sensitivity of observer B was 53% for T2 SE and 83% for FLAIR; the specificity for observer B was 93% for the T2 SE and 100% for FLAIR. CONCLUSION: Coronal FLAIR images provide a similar or increased yield in the detection of MTS compared with T2-weighted SE images.     

Staggering in low-spin nuclear spectra of gamma -soft or triaxial nuclei

MR imaging with gadopentetate dimeglumine (MR arthrography) is a new technique for evaluating the shoulder. Early clinical experience indicates that MR arthrography improves the visualization of intraarticular structures [1-3]. On T1-weighted images, high-signal contrast solution outlines the low-signal surface of the cuff tendons, the contour of the glenoid labrum, and the course of the glenohumeral ligaments. This essay illustrates the anatomic features of normal glenohumeral structures seen on MR arthrography and common pathologic disorders of the labral-ligamentous complex and rotator cuff.     

Cerebrospinal fluid fistula: detection with MR cisternography

PURPOSE: Our goal was to assess the role of MR cisternography in the examination of patients with suspected CSF rhinorrhea. METHODS: MR cisternography was performed as a heavily T2-weighted fast spin-echo study with fat suppression and video reversal of the images in 37 patients over a 3-year interval. Twenty-four of the patients subsequently had exploratory surgery for fistula. Statistical analysis of the surgical results was compared with the findings at MR cisternography. RESULTS: MR cisternography showed significant correlation with surgical findings, with sensitivity, specificity, and accuracy of 0.87, 0.57, and 0.78, respectively. CONCLUSION: MR cisternography proved to be an accurate diagnostic imaging technique in the evaluation of suspected CSF rhinorrhea.     

Hepatic lesions: discrimination of nonsolid, benign lesions from solid, malignant lesions with heavily T2-weighted fast spin-echo MR imaging

PURPOSE: To determine whether the combined use of heavily and moderately T2-weighted fast spin-echo magnetic resonance (MR) images improves differentiation of non-solid, benign hepatic lesions from solid malignancies. MATERIALS AND METHODS: Three radiologists reviewed moderately (n = 133) and heavily (n = 133) T2-weighted and multiphasic dynamic contrast material-enhanced (n = 93) MR images in 133 patients with proved focal hepatic lesions (95 benign, 38 malignant). The radiologists used a five-point scale to rate their confidence in determination of malignancy. RESULTS: All three reviewers were statistically significantly better able to differentiate small (diameter less than 3 cm; n = 84) benignancies from small malignancies with the combination of moderately and heavily T2-weighted images (area under the receiver operating characteristic curve, 0.99 for each reader) than with moderately T2-weighted images alone (area, 0.88-0.90; P < .05). Confident diagnoses were rendered in 69 (82%) patients, with 100% accuracy for the combined use of moderately and heavily T2-weighted images. For larger lesions (diameter 3 cm or larger; n = 49), accurate differentiation was possible with moderately T2-weighted images alone. Additional use of multiphasic images did not improve the sensitivity, specificity, or accuracy of image interpretation. CONCLUSION: The combined use of moderately and heavily T2-weighted fast spin-echo MR images improves differentiation of small benign hepatic lesions from small malignant lesions.     

Preoperative staging of endometrial carcinoma: diagnostic effect of T2-weighted fast spin-echo MR imaging

PURPOSE: To evaluate the usefulness of T2-weighted fast spin-echo magnetic resonance (MR) imaging with a 512 x 256 matrix for assessment of the preoperative stage of endometrial carcinoma. MATERIALS AND METHODS: Twenty-eight women with histopathologically proved endometrial carcinoma underwent preoperative T2-weighted fast spin-echo, dynamic T1-weighted fast spin-echo, and postcontrast T1-weighted spin-echo MR imaging with a phased-array surface coil. The uterine long-axis planes in each sequence were reviewed at separate sessions by three radiologists blinded to the histopathologic data. RESULTS: For the diagnosis of myometrial invasion, no statistically significant differences were found among T2-weighted imaging, dynamic imaging, and postcontrast T1-weighted imaging. For the diagnosis of deep myometrial invasion, T2-weighted and dynamic images showed higher specificity than postcontrast T1-weighted images (T2-weighted, 89%; dynamic, 88%; and postcontrast T1-weighted, 80%). For cervical invasion, T2-weighted and dynamic images showed larger areas under receiver operating characteristic curves than did postcontrast T1-weighted images (T2-weighted, 0.78; dynamic, 0.71; and postcontrast T1-weighted, 0.67). CONCLUSION: T2-weighted imaging is useful for identifying the stage of endometrial carcinoma.     

Normal uterus and FIGO stage I endometrial carcinoma: dynamic gadolinium-enhanced MR imaging

Dynamic magnetic resonance (MR) imaging was performed on a 1.5-T superconducting unit for evaluation of 26 stage I endometrial carcinomas. To establish the appearance of the normal uterus, 27 normal uteri were also evaluated. After rapid injection of gadopentetate dimeglumine, dynamic images were obtained every 30 seconds with the spin-echo technique in the sagittal plane. On dynamic studies of endometrial carcinoma, the tumor-myometrial contrast was marked at 120 seconds after administration of gadopentetate dimeglumine (contrast-to-noise ratio [C/N], 26.0). The tumor-myometrial contrast on the dynamic study was more marked than that on postcontrast T1-weighted images (C/N, 10.0) and on T2-weighted images (C/N, 2.14). Dynamic and postcontrast MR images were superior in enabling differentiation of viable tumors from necrosis or residual secretion in the endometrial cavity. In the evaluation of presence of tumor and myometrial invasion, the accuracy of T2-weighted imaging and dynamic imaging was 67.9% and 84.9%, respectively.     

MR diagnosis of labral tears of the shoulder: value of T2*-weighted gradient-recalled echo images made in external rotation

OBJECTIVE: Because several studies have shown that conventional MR imaging can fail to diagnose a significant percentage of labral tears, some authors have proposed obtaining T2*-weighted gradient-recalled echo images with the humerus in external rotation. The purpose of our study was to determine whether the diagnostic accuracy of detecting anteroinferior labral tears by MR imaging would be improved by adding a T2*-weighted gradient-recalled echo sequence with the humerus in external rotation. MATERIALS AND METHODS: The study included 24 patients for whom axial MR images of the shoulder were obtained with the humerus in both the neutral position and external rotation. Two observers interpreted the images made in the neutral position and then noted any change in their interpretations after viewing findings on the external-rotation images. MR results were correlated with surgical findings. At surgery, 14 anteroinferior labra were found to be torn and 10 were found to be intact. RESULTS: Both observers identified one patient for whom a surgically proved labral tear was seen only on the external-rotation images. The sensitivity increased from 0.43 to 0.50 (p = .35) for observer 1 and from 0.36 to 0.43 (p = .35) for observer 2. The specificity of 0.90 for both observers remained unchanged. The accuracy improved from 0.62 to 0.67 for observer 1 and from 0.55 to 0.62 for observer 2. CONCLUSION: The addition of external-rotation T2*-weighted gradient-recalled echo images to the MR examination for tears of the anteroinferior labrum leads to a small but statistically insignificant increase in diagnostic sensitivity. We conclude that the small increase in sensitivity does not justify the routine use of this sequence.     

Ligaments of the ankle: normal anatomy with MR arthrography

PURPOSE: Our purpose was to define the normal MR arthrographic anatomy of ankle ligaments. METHOD: Prior to injection of intraarticular gadolinium in cadaveric ankle joints, proton density and T2-weighted images were obtained to assess the integrity of the ligaments and tendons as well as the amount of preexisting joint effusion. Following injection of 10 ml of contrast agent (gadopentetate dimeglumine 1:250, Omnipaqe 300, Knox gelatin 50%, and methylene blue), T1-weighted images with fat saturation in axial, oblique axial, coronal, and sagittal planes were obtained in neutral, dorsiflexion, and plantar flexion positions. Specimens were sectioned, allowing anatomic and MR correlation. RESULTS: Contrast agent outlining anterior and posterior aspects of the anterior talofibular ligament and posterior talofibular ligament (PTAF) was a normal finding, related to anterior and posterior recesses of the ankle joint that extend out beyond these ligaments in an anteroposterior direction above the level of the ligaments. Intraarticular contrast material allowed resolution of superficial and deep components of the posterior tibiofibular ligament. Both were seen separately from PTAF with dorsiflexion. Posterior intermalleolar ligament was not present in our specimens. Visualization of calcaneofibular ligament was much improved by contrast material outlining the articular aspect of the ligament. Visualization of the syndesmotic ligamentous complex also was improved by contrast material outlining the articular side of the ligaments and separating them from adjacent bone. Superiorly, the distribution of contrast agent was limited by the interosseous ligament. Visualization of the medial collateral ligaments was not improved by the presence of the intraarticular contrast material. CONCLUSION: MR arthrography of the ankle allows improved visualization and evaluation of the lateral and syndesmotic ligamentous complex.     

High-resolution three-dimensional magnetic resonance imaging for the investigation of knee joint damage during the time course of antigen-induced arthritis in rabbits

OBJECTIVE: To investigate the efficacy of high-resolution 3-dimensional magnetic resonance imaging (3-D MRI) with gadolinium contrast agent enhancement in monitoring soft tissue and hard tissue changes during the course of antigen-induced arthritis in rabbits, comparing the images with the final histologic outcome. METHODS: Arthritis was induced by intraarticular injection of methylated bovine serum albumin into rabbits that had been presensitized to the same antigen. MRI was carried out before and on predetermined days after the onset of inflammatory arthritis, up to day 60. At each time point, 3-D gradient-echo images were acquired. At the end of the study, the knee joints were processed for histologic study. RESULTS: Time-related inflammatory changes, such as soft tissue swelling, were seen initially, followed by a reduction in the acute swelling and a progression to hard tissue damage at later time points. The final 3-D data sets were then used to compare MR images with the histologic sections. The knee joints were sectioned in the sagittal, coronal, or transverse direction. Comparison of final images and histologic features at day 60 enabled a more complete interpretation of the MR images, allowing direct correlation of joint damage observed using the MRI technique with that seen in the final histologic analysis. CONCLUSION: Qualitative information derived from MR images correlated extremely well with histologic findings. These results indicate the great potential of MRI for noninvasive investigation of drug effects in this model of arthritis.