Spinal cord schistosomiasis: MR imaging appearance with surgical and pathologic correlation

BACKGROUND AND PURPOSE: Spinal cord involvement is a rare manifestation of schistosomiasis. We describe the MR imaging findings of spinal cord schistosomiasis in correlation with surgery and pathology. METHODS: We report eight cases of spinal cord schistosomiasis. All patients were men (mean age, 16.7 years) with neurologic manifestations who had been referred for spinal MR imaging. In all cases, spinal masses were surgically removed. MR imaging findings were correlated with surgery and pathology. RESULTS: MR imaging showed moderate expansion of the distal spinal cord in all cases. Abnormalities were isointense to cord in T1 and patchy hyperintense in T2-weighted spin-echo images (n = 8). Three forms of contrast enhancement were recognized: (1) intramedullary nodular (n = 8); (2) peripheral (n = 8); and (3) linear radicular (n = 4). Total gross surgical removal of masses by using the Cavitron ultrasonic surgical aspirator was possible in six cases. Diagnosis was established by identification of ova in histopathologic studies: Schistosoma mansoni (n = 3), S. hematobium (n = 1), and uncertain species (n = 4). Intramedullary nodular enhancement was correlated to multiple schistosomiasis microtubercles. Peripheral enhancing lesions correlated to thickened leptomeninges infested by chronic granulomatous inflammatory cells and schistosoma eggs. Linear radicular enhancement correlated with thickened resected nervous roots infested by granulomatous cells and schistosoma eggs. CONCLUSION: Multinodular intramedullary contrast enhancement of the distal cord enabled correct presumptive preoperative MR imaging diagnosis of spinal schistosomiasis in three cases. Accurate diagnosis, through recognition of its MR imaging appearance, allows early treatment and better prognosis of spinal cord schistosomiasis.     

MR imaging of intradural inflammatory diseases of the spine

Twenty-eight patients with intradural inflammatory disease of the spine were studied in order to characterize the MR imaging findings of infectious and inflammatory conditions. Patients were categorized according to the spinal compartment involved. Among the 12 patients in the intradural extramedullary group, unenhanced scans were either normal or nonspecific while contrast-enhanced scans were helpful in visualizing and localizing the lesion. Nevertheless, contrast-enhanced MR studies were unable to differentiate infection and inflammation from tumor in this compartment. Among 16 patients with intramedullary lesions, four had granulomatous disease and 12 had nongranulomatous disease. The granulomatous lesions resembled tumors and displayed MR characteristics of a focal lesion with large nodular enhancement. The patients with nongranulomatous intramedullary lesions exhibited two subsets of MR findings. In the first subset of nine patients, diffuse cord swelling and high signal were seen on long TR images, combined with either no enhancement or peripheral, diffuse, or speckled enhancement of the spinal cord on contrast-enhanced short TR images. In the second subset of three patients, minimal or no spinal cord swelling was displayed despite the visualization of high signal on long TR scans and nodular enhancement with contrast administration on short TR scans. Both subsets were sufficiently unique that nongranulomatous myelitis could usually be differentiated from spinal cord tumors.     

Spinal MR findings in continuous epidural analgesia without infection

BACKGROUND AND PURPOSE: Spinal epidural abscesses are major complications of epidural anesthesia, and their MR features have been reported. In patients receiving continuous infusion via an epidural catheter, MR findings may mimic those of spinal epidural abscess in the absence of infection. The purpose of this study was to assess the spinal MR findings associated with continuous epidural anesthesia. METHODS: Spinal MR findings in five consecutive patients receiving continuous epidural anesthesia were retrospectively evaluated. Axial and sagittal T1- and T2-weighted spin-echo and contrast-enhanced fat-suppressed T1-weighted spin-echo images were obtained. Infection was ruled out on microbiologic analysis three patients and on follow-up in two. Each lesion was evaluated for its MR signal intensity, location, extent, delineation, and enhancement pattern. In three patients, follow-up MR imaging was performed within 5-150 days, and the images were compared. RESULTS: Posterior epidural lesions were identified in all five patients. The lesions were isointense to hypointense relative to the spinal cord on T1-weighted images, isointense relative to CSF on T2-weighted images, and well enhanced on enhanced T1-weighted images. The anomalous enhancement involved two to seven vertebral bodies. In one patient, the enhanced lesion slightly compressed the spinal cord. On follow-up MR imaging, the epidural lesions decreased in two patients and did not change in one. CONCLUSION: Continuous epidural anesthesia can result in MR findings similar to those of epidural abscess, even in the absence of infection.     

MR imaging findings in spinal infections: rules or myths?

PURPOSE: To systematically evaluate magnetic resonance (MR) imaging findings described as being indicative of spinal infection in patients with proven spinal infection. MATERIALS AND METHODS: Contrast material-enhanced spinal MR images obtained in 46 consecutive patients (22 women, 24 men; mean age, 58.2 years) with culture or histologic examination results positive for spinal infection were systematically evaluated by two observers. Tuberculous and postoperative infections were excluded. Disk signal intensity and disk height, presence of the nuclear cleft, vertebral signal intensity alterations, endplate erosions on T1-weighted MR images, and presence of paraspinal or epidural inflammation were evaluated. Patient charts and surgical reports were reviewed. RESULTS: In the 44 patients with disk infection, MR imaging criteria with good to excellent sensitivity included presence of paraspinal or epidural inflammation (n = 43, 97.7% sensitivity), disk enhancement (n = 42, 95.4% sensitivity), hyperintensity or fluid-equivalent disk signal intensity on T2-weighted MR images (n = 41, 93.2% sensitivity), and erosion or destruction of at least one vertebral endplate (n = 37, 84.1% sensitivity). Effacement of the nuclear cleft was only applicable in 18 patients (n = 15, 83.3% sensitivity). Criteria with low sensitivity included decreased height of the intervertebral space (n = 23, 52.3% sensitivity) and disk hypointensity on T1-weighted MR images (n = 13, 29.5% sensitivity). Involvement of several spinal levels occurred in seven (16%) patients. Other spinal infections included isolated vertebral osteomyelitis (n = 1) and primary epidural abscess (n = 1). CONCLUSION: Most MR imaging criteria commonly used to diagnose disk infections offer good to excellent sensitivity. In atypical manifestations of proven spinal infections, however, some of the classically described MR imaging criteria may not be observed.     

Follow-up MR imaging in patients with pyogenic spine infections: lack of correlation with clinical features

BACKGROUND AND PURPOSE: Follow-up MR imaging examinations are increasingly used to monitor response to treatment in patients with spine infection. We aim to describe follow-up MR imaging examination findings 4-8 weeks after diagnosis and initiation of treatment of spine infections and to compare with clinical findings. MATERIALS AND METHODS: Thirty-three patients with spinal infection and available baseline and 4-8-week follow-up MRIs were included in this retrospective cohort study. Baseline and follow-up MR imaging were graded by 2 neuroradiologists blinded to clinical characteristics and outcome. Clinical findings and outcomes were independently obtained by retrospective review of the medical record. RESULTS: Compared with baseline MR imaging examinations, follow-up MR imaging more frequently demonstrated vertebral body loss of height (26/33 [79%] versus 14/33 [47%]; P < .001) and less frequently demonstrated epidural enhancement (19/32 [59%] versus 29/33 [88%]; P = .008), epidural canal abscess (3/32 [9%] versus 15/33 [45%]; P = .001), and epidural canal compromise (10/32 [31%] versus 19/33 [58%]; P = .008). Most follow-up MR imaging examinations demonstrated less paraspinal inflammation and less epidural enhancement compared with baseline. However, vertebral body enhancement, disk space enhancement, and bone marrow edema more often were equivocal or appeared worse compared with baseline. Twenty-one of 32 (66%) follow-up MR imaging examination overall grades were considered improved, 5 (16%) were equivocal, and 6 (19%) were worse. No single MR imaging finding was associated with clinical status. CONCLUSION: Soft tissue findings, not bony findings, should be the focus of clinicians interpreting follow-up MR imaging results. No single MR imaging parameter was associated with the patients' clinical status.     

Small hepatocellular carcinoma treated with percutaneous RF ablation: MR imaging follow-up.

OBJECTIVE: The purpose of our study was to determine the usefulness of MR imaging in the follow-up evaluation of small hepatocellular carcinoma lesions treated with RF ablation. SUBJECTS AND METHODS: The study group included 37 patients with a single hepatocellular carcinoma lesion less than 3 cm in diameter. A strict protocol required follow-up MR imaging every 6 months after RF treatment. At each follow-up visit, the findings on unenhanced and dynamic gadolinium-enhanced MR images were correlated with those on contrast-enhanced CT images and with results of fine-needle aspiration biopsy. In five patients who underwent surgical resection after the 6-month follow-up examination, comparison with histologic findings of surgical specimens was also performed. RESULTS: Correct diagnosis of complete or partial tumor necrosis was made in 32 (86%) of the 37 patients with the use of unenhanced and dynamic gadolinium-enhanced MR images. Hypointensity on T2-weighted images and loss of enhancement on dynamic MR images corresponded to completely necrotic lesions in all patients. Conversely, intratumoral regions of hyperintensity on T2-weighted images and enhancement on dynamic MR images did not always correlate to residual viable tumor. MR imaging and CT findings agreed in the evaluation of therapeutic response in all patients. CONCLUSION: Our experience confirms that MR imaging is useful for evaluating the effectiveness of RF therapy in achieving tumor regression.     

Intramedullary spinal cord tumors: MR imaging, with emphasis on associated cysts

Fifteen magnetic resonance (MR) imaging studies in 16 patients with intramedullary spinal cord lesions were correlated with surgical findings in all patients and with results of intraoperative spinal sonography (IOSS) in eight. Tumor extent was defined accurately in all but two patients by MR imaging; these lesions were found at surgery to have been underestimated by one to two vertebral body segments. Most tumors had lengthened T1 and T2 relaxation times. Intratumoral cysts were detected by MR imaging in one of eight cases, and rostral and caudal cysts were defined in only two of ten cases. The poor detection rate is attributed to poor spatial and contrast resolution. Preoperative MR imaging to define the extent of cord enlargement and IOSS to define cystic structures appears to be the optimal method of tumor management pending our further study.     

Acute spinal cord injury: magnetic resonance imaging correlated with myelopathy

Thirty-one patients (29 males and two females, 13-87 years of age (mean, 46.7 years] with acute spinal cord injury were studied by MR (magnetic resonance) imaging and the results were correlated with neurological findings. Magnetic resonance images were obtained with a 0.5 T superconductive MR scanner (Phillips Gyroscan S5). Initial imaging was performed within 24 hours after trauma in 13 patients, 1-7 days in 13 patients and 7-14 days in five patients. Twenty-six patients underwent follow-up examinations with MR imaging. Cord abnormalities including cord compression (23 patients), cord swelling (seven patients), and abnormal signal intensities on either T1 or T2-weighted images (26 patients) were observed on initial examination. Multivariate analysis showed that cord compression and abnormal intensities on T1-weighted images were important prognostic indicators. Hyperintensity on T2-weighted images was non-specific but correlated well with clinical recovery. Magnetic resonance imaging is useful in predicting the prognosis and for planning treatment following spinal cord injuries.     

Picture archiving and communication system: effect on reporting of incidental findings

PURPOSE: To determine the effect of a picture archiving and communication system (PACS) on reporting of incidental findings outside the area of interest, with a focus on lumbar spinal magnetic resonance (MR) imaging. MATERIALS AND METHODS: Results of 2,500 lumbar spinal 1.5-T MR examinations were reviewed. These included 500 consecutive lumbar spinal MR reports for each of 5 years: 1 year prior to PACS introduction, 1 year during transition to PACS, and 3 consecutive years thereafter. Incidental findings cited in the reports were tabulated, and the frequency, organ system involved, and radiologist recommendations in each case were noted and compared, as were projected expenses based on the Medicare payment scale for recommended follow-up studies. Results of available follow-up studies were also reviewed. RESULTS: The number of incidental findings increased from 19 before PACS to 31 during transition and 53, 49, and 50 after PACS implementation, which resulted in a maximum increase of 179%. The increase was statistically significant during each post-PACS year. The most common incidental findings involved potential renal, pelvic, hepatic, pulmonary, and lymph node abnormalities. The total number of recommended follow-up studies increased from five before PACS to 15 during transition and 32, 22, and 18 after PACS implementation, with a maximum increase of as much as 540%. Recommended ultrasonographic studies increased the most from two in the pre-PACS year to 11 during transition and 27, 17, and 14 in the 3 post-PACS years. Follow-up expense increased by a mean of 146% after PACS implementation from 4,221 dollars per 1,000 studies in the pre-PACS year to 9,307 dollars, 13,426 dollars, 10,558 dollars, and 8,252 dollars thereafter. Of the 202 incidental findings, four represented occult malignancy, which is an expense of 5,721 dollars per diagnosis. CONCLUSION: The introduction of PACS into radiology practice for lumbar spinal MR imaging appears to be associated with an increased number of reported incidental findings and recommended follow-up studies.     

MR imaging of spinal infection

Magnetic resonance (MR) imaging plays a pivotal role in the diagnosis and management of spinal infection, enjoying a high sensitivity and specificity. A thorough understanding of spinal anatomy and the physicochemical pathological processes associated with infection is a desirable prerequisite allowing accurate interpretation of the disease process. Apart from confirmation of the disease, MR imaging is also best suited to excluding multifocal spinal involvement and the detection/exclusion of complications. It plays an essential role in the decision-making process concerning conservative versus surgical treatment and is also the best imaging method to monitor the effect of treatment. The MR features of infection confidently exclude tumor, degeneration, and so forth as the underlying process; differentiate pyogenic from granulomatous infections in most cases; and can suggest the rarer specific infective organisms.     

Correlation of MR imaging findings with intraoperative findings after cervical spine trauma

BACKGROUND AND PURPOSE: There are limited data correlating MR imaging and anatomic findings of ligamentous injury in cervical spine trauma. This study compares acute MR imaging with surgical observations of disk/ligamentous injury after blunt cervical trauma. MATERIALS AND METHODS: Consecutive patients with acute cervical spine trauma who underwent preoperative MR imaging and surgery from 1998 to 2001 were identified. MR imaging was obtained within 48 hours of injury for most patients. All scans included sagittal T1, T2 fat-saturated, and short tau inversion recovery sequences. At surgery, extent of injury at the operated level was recorded on a standardized form for either anterior or posterior structures or both depending upon the operative approach. MR examinations were separately evaluated by 2 readers blinded to the intraoperative findings. Radiologic and surgical findings were then correlated. RESULTS: Of 31 patients, an anterior surgical approach was chosen in 17 patients and a posterior approach in 13 patients. In one patient anterior and posterior approaches were utilized. Seventy-one percent of patients had spinal cord injury on MR imaging. MR imaging was highly sensitive for injury to disk (93%), posterior longitudinal ligament (93%), and interspinous soft tissues (100%), but it was less sensitive for injury to the anterior longitudinal ligament (71%) and ligamentum flavum (67%). For most ligamentous structures, there was limited agreement between specific MR imaging findings and injury at surgery. CONCLUSION: In acute cervical spine trauma, MR imaging has moderate to high sensitivity for injury to specific ligamentous structures but limited agreement between specific MR imaging findings and injury at surgery. MR imaging may overestimate the extent of disruptive injury when compared with intraoperative findings, with potential clinical consequences.     

Paget disease: MR imaging findings

Magnetic resonance (MR) images of 13 patients with Paget disease were reviewed, and findings were correlated with those from computed tomographic (CT) scans, radiographs, and, in two patients, surgical biopsy. MR imaging findings correlated with CT and radiographic findings of cortical thickening, increased size of bone, and coarse thickened trabeculae. Focal or diffuse decreased signal intensity, representing dense bone, was seen on images obtained with short and long repetition times (TRs) and echo times (TEs); high-signal foci, representing fat collections, were seen on short TR/TE images; and high-signal foci, representing fibrovascular marrow in active Paget disease, were seen on long TR/TE images. Complications of Paget disease-including basilar invagination, spinal stenosis, and sarcoma--were well identified on MR images. Although MR imaging is not generally used in diagnosis of Paget disease, the disease will be encountered more frequently as more MR imaging examinations are performed. An awareness of the range of findings in Paget disease is useful in evaluating MR images of the musculoskeletal and other systems.     

Can imaging findings help differentiate spinal neuropathic arthropathy from disk space infection? Initial experience

PURPOSE: To determine if radiographic, computed tomographic (CT), and magnetic resonance (MR) imaging findings can help differentiate spinal neuropathic arthropathy from disk space infection. MATERIALS AND METHODS: Imaging studies in 33 patients were evaluated, including 14 patients with spinal neuropathic arthropathy (12 radiographic, seven CT, and six MR studies) and 19 with disk space infection (13 radiographic, nine CT, and 12 MR studies). Potential imaging discriminators, including endplate sclerosis or erosions, osteophytes, spondylolisthesis, facet involvement (narrowing or erosions), vacuum disk, paraspinal soft-tissue mass, joint disorganization, and osseous joint debris, were recorded, as were MR imaging signal intensity and gadolinium-enhancement characteristics. RESULTS: The most helpful findings for diagnosis of spinal neuropathic arthropathy were vacuum disk on radiographs and CT images, debris on radiographs and CT and MR images, disorganization on radiographs and CT and MR images, facet involvement on radiographs and CT and MR images, spondylolisthesis on CT and MR images, diffuse signal intensity patterns in vertebral bodies on MR images, and rim enhancement of disks on gadolinium-enhanced MR images. Findings that were not helpful included endplate sclerosis and erosions, osteophytes, paraspinal soft-tissue mass, and decreased disk height. CONCLUSION: Vacuum disk, facet involvement, vertebral body spondylolisthesis, joint disorganization and debris, and gadolinium-enhancement patterns of vertebral bodies and disks may help differentiate spinal neuropathic arthropathy from infection.     

Breast MR imaging in patients with axillary node metastases and unknown primary malignancy.

PURPOSE: To assess the usefulness of magnetic resonance (MR) imaging of the breast in patients with malignant axillary adenopathy and unknown primary malignancy. MATERIALS AND METHODS: Between October 1993 and December 1997, 38 women with malignant axillary adenopathy and negative mammographic and physical examination findings underwent contrast material-enhanced MR imaging. Sixteen patients were excluded due to axillary tail cancer (n = 7), lack of follow-up (n = 4), second primary malignancy (n = 3), or chemotherapy before MR imaging (n = 2). The study population comprised the remaining 22 patients. Histopathologic findings were available in 20 patients; follow-up MR imaging findings were available in two patients. RESULTS: MR imaging depicted a primary breast cancer in 19 patients (86%; identified at excisional biopsy or mastectomy in 17, resolved on follow-up MR images during treatment in two). MR imaging depicted 4-30-mm cancers (mean, 17 mm), which correlated closely with histopathologic size. Two patients (9%) had false-negative findings: (a) One had a 2-mm invasive ductal carcinoma, and (b) one had 17- and 20-mm invasive ductal carcinomas. Of the 19 patients, 11 underwent mastectomy, seven underwent breast-conservation therapy, and one did not undergo a surgical procedure. CONCLUSION: MR imaging is very sensitive for the detection of mammographically and clinically occult breast cancer in patients with malignant axillary adenopathy. In these patients, MR imaging offers potential not only for cancer detection but also for staging the cancer within the breast, which may be useful for treatment planning.     

Spinal infection: evaluation with MR imaging and intraoperative US

Magnetic resonance (MR) images of the spine and/or intraoperative spinal ultrasound (US) in 24 patients with spinal infections were reviewed and correlated with clinical and pathologic data to determine their diagnostic value. In disk space infection with osteomyelitis and in retrospinal abscess, MR images showed characteristic findings, whereas in myelitis, MR images demonstrated nonspecific abnormalities. The appearance on MR images of epidural abscesses ranged from clearly identifiable extradural masses with high-intensity signal on spin-echo T2-weighted images to extensive inhomogeneous collections of mixed signal intensities, difficult to distinguish from adjacent meningitis. Myelography with high-resolution computed tomography (CT) and intraoperative spinal US was superior to MR imaging in demonstrating epidural abscesses when there was concomitant meningitis. With intraoperative spinal US, epidural abscesses could be located and their decompression monitored. MR imaging is recommended as the initial screening procedure in spinal infection; in those few patients with nondiagnostic MR images, myelography with high-resolution CT should be the supplementary study. If surgery is planned, intraoperative spinal US should be used.     

MR of CNS sarcoidosis: correlation of imaging features to clinical symptoms and response to treatment.

BACKGROUND AND PURPOSE: Sarcoidosis is an idiopathic systemic granulomatous disease, recognized in a patient when clinical and radiologic findings are confirmed by histopathologic analysis. The objective was to identify a relationship between MR imaging and clinical findings in CNS sarcoidosis. METHODS: The clinical charts of 461 patients with biopsy-proved sarcoidosis were reviewed retrospectively. Criteria for including patients in the study included those with symptoms referable to the CNS, excluding those with another explanation for their symptoms, those with headaches or other subjective complaints without accompanying objective findings, and those with peripheral neuropathy other than cranial nerve involvement or myopathy without CNS manifestations. Thirty-four of 38 patients whose conditions met the criteria for CNS sarcoidosis underwent a total of 82 MR examinations. The positive imaging findings were divided into categories as follows: pachymeningeal, leptomeningeal, nonenhancing brain parenchymal, enhancing brain parenchymal, cranial nerve, and spinal cord and nerve root involvement. Treatment response, clinical symptomatology, and any available histopathologic studies were analyzed with respect to imaging manifestations in each of the categories. RESULTS: Eighty-two percent of the patients with sarcoidosis with neurologic symptoms referable to the CNS had findings revealed by MR imaging. However, eight (40%) of 20 cranial nerve deficits seen at clinical examination of 13 patients were not seen at contrast-enhanced MR imaging, and 50% of the patients with symptoms referable to the pituitary axis had no abnormal findings on routine contrast-enhanced MR images. In contradistinction, 44% of 18 cranial nerves in nine patients with MR evidence of involvement had no symptoms referable to the involved cranial nerve. Clinical and radiologic deterioration occurred more commonly with leptomeningeal and enhancing brain parenchymal lesions. CONCLUSION: MR imaging can be used to confirm clinical suspicion and to show subclinical disease and the response of pathologic lesions to treatment.     

MR imaging with quantitative diffusion mapping of tacrolimus-induced neurotoxicity in organ transplant patients

Our objective was to investigate brain MR imaging findings and the utility of diffusion-weighted (DW) imaging in organ transplant patients who developed neurologic symptoms during tacrolimus therapy. Brain MR studies, including DW imaging, were prospectively performed in 14 organ transplant patients receiving tacrolimus who developed neurologic complications. In each patient who had abnormalities on the initial MR study, a follow-up MR study was performed 1 month later. Apparent diffusion coefficient (ADC) values on the initial MR study were correlated with reversibility of the lesions. Of the 14 patients, 5 (35.7%) had white matter abnormalities, 1 (7.1%) had putaminal hemorrhage, and 8 (57.1%) had normal findings on initial MR images. Among the 5 patients with white matter abnormalities, 4 patients (80.0%) showed higher than normal ADC values on initial MR images, and all showed complete resolution on follow-up images. The remaining 1 patient (20.0%) showed lower than normal ADC value and showed incomplete resolution with cortical laminar necrosis. Diffusion-weighted imaging may be useful in predicting the outcomes of the lesions of tacrolimus-induced neurotoxicity. Electronic Publication     

Preoperative assessment of breast cancer: sonography versus MR imaging

OBJECTIVE: The purposes of our study were to compare the diagnostic value of whole-breast sonography and MR imaging as adjunctive techniques to mammography and to determine whether MR imaging should be used routinely in the preoperative assessment of patients with suspected breast cancer. SUBJECTS AND METHODS:. One hundred four women (age range, 34-84 years; mean age, 60 years) with findings highly suggestive of malignancy in the breast were examined with mammography, sonography, and dynamic MR imaging before undergoing surgery. All visualized suspicious lesions were correlated histologically. The diagnostic relevance of sonographic and MR imaging findings was compared with the diagnostic value of the findings of clinical examination and mammography alone. RESULTS:. Twenty-seven tumors showed multifocal or multicentric invasive growth at pathology. Of these 27, 48% were correctly diagnosed via mammography alone; 63%, via the combination of mammography and sonography; and 81%, via MR imaging. Nine of the index tumors were invisible on mammography but were detected on sonography. Use of sonography benefited 13 patients and produced two studies with false-positive findings. Use of MR imaging benefited seven patients and produced eight studies with false-positive findings. In summary, 93% of all patients gained no advantage from MR imaging. Relevant additional findings were significantly more frequent in patients with dense breasts. CONCLUSION: Although MR imaging is most sensitive for the detection of small tumors, routine preoperative MR imaging appears to be unnecessary for most patients if a combination of mammography and whole-breast sonography is used. Additional MR imaging can be restricted to problematic cases in women with dense breast parenchyma.     

Serial MR Imaging of Annular Tears in Lumbar Intervertebral Disks

BACKGROUND AND PURPOSE: Annular tears of lumbar intervertebral disks are found in both symptomatic and asymptomatic persons; therefore, it is difficult to determine whether these findings indicate acute abnormality. Our purpose was to determine whether the MR imaging findings of tears (ie, hyperintensity and contrast enhancement) of the annulus fibrosus persist or resolve over time. METHODS: A radiologic database was searched for spinal MR imaging examinations noting annular tears. Eighteen patients were identified who had undergone more than one spinal MR imaging study. The images were reviewed for presence or absence of annular tears, defined as an area of hyperintensity on T2-weighted images or enhancement in the posterior annulus, separate from the nucleus pulposus. RESULTS: Annular tears were observed at 29 levels in 18 patients. Two tears developed during the follow-up interval. When contrast-enhanced images were obtained during serial examinations, 10 (100%) of 10 enhancing annular tears persisted on the follow-up contrast-enhanced T1-weighted images (mean interval, 17.2 months; SD, 12.3 months). High signal intensity on T2-weighted MR images was noted in 26 (96%) of 27 tears initially and persisted in 23 (88%) of 26 (mean interval, 21.9 months; SD, 15.0 months). CONCLUSION: Hyperintensity on T2-weighted MR images and enhancement of annular tears could not be used to determine the tears' acuity over the range of follow-up provided in this study.