Trends in the utilization of MR angiography and body MR imaging in the US Medicare population: 1993-1998

PURPOSE: To determine the trends in utilization of non-neurologic (ie, body) magnetic resonance (MR) imaging and of MR angiographic examinations performed from 1993 to 1998, the trends in non-radiologist participation in MR imaging, and the relative reimbursements for these examinations compared with those for all other noninvasive imaging studies performed in 1998. MATERIALS AND METHODS: By using the 1993, 1996, and 1998 nationwide Medicare Part B databases, utilization rates per 100,000 Medicare beneficiaries and physician reimbursements were determined for seven MR angiography and 14 body MR imaging CPT-4 (Current Procedural Terminology, version 4) codes. Medicare specialty codes were used to categorize physicians as radiologists or non-radiologists. RESULTS: The utilization rate per 100,000 Medicare beneficiaries for all 21 MR angiography and body MR imaging codes increased from 649 in 1993 to 1,253 in 1996 and to 1,876 in 1998--a 189% increase. These rates represented 0.55% of the total noninvasive imaging volume in 1998 and 2.8% of physician reimbursements. Musculoskeletal MR imaging utilization increased 142% from 1993 to 1998 compared with a 58% increase in the utilization of other body MR imaging studies. Non-radiologist participation in musculoskeletal MR imaging increased from 2.9% in 1993 to 3.6% in 1996 and to 5.6% in 1998. CONCLUSION: MR angiography and body MR imaging utilization rates increased substantially from 1993 to 1998. However, these studies still account for a minor fraction of all noninvasive imaging examinations performed and fees reimbursed. MR angiography and musculoskeletal MR imaging utilization has increased rapidly. Non-radiologist participation in musculoskeletal MR imaging is increasing.     

Body MR imaging and CT volume: variations and trends based on an analysis of medicare and fee-for-service health insurance databases

OBJECTIVE: We examined Medicare and fee-for-service data sets to understand better the utilization of MR imaging for imaging the pelvis, abdomen, and chest relative to its use in imaging for other body parts and to the utilization of CT. MATERIALS AND METHODS: CT and MR imaging procedure volumes for pelvis, abdomen, chest, and total were extracted from the 1993, 1996, and 1999 Health Care Financing Administration Physician/Supplier Procedure Summary Master Files, based on CPT-4 codes. We also analyzed a fee-for-service health insurance database for January 1998 through July 1999 from a single northeastern state, which included provider location (rural, suburban, or urban) and type (teaching or nonteaching site). RESULTS: The greatest 3-year Medicare increase was for abdominal MR imaging, from 1996 to 1999 (101% increase). However, pelvic, abdominal, and chest MR imaging together remained less than 5% of total MR imaging. Abdominal MR imaging increased more than did total MR imaging in all 10 Health Care Financing Administration regions. In the fee-for-service database, the relative procedure volume of abdominal MR imaging varied approximately fivefold from rural to urban provider locations, and approximately double from nonteaching to teaching hospitals. CONCLUSION: Although far more abdominal CT than abdominal MR imaging is performed, the rate of abdominal MR imaging utilization has increased more rapidly since 1993. The relative procedure volume of abdominal MR imaging varied more than fivefold from rural to urban provider locations and double from nonteaching to teaching hospitals.     

Assessment of transient ischemic attack with diffusion- and perfusion-weighted imaging

BACKGROUND: Diagnosing TIA can be difficult, since evidence of brain ischemia is habitually lacking on CT and conventional MR imaging. It has been suggested that patients with acute brain infarction on neuroimaging should be considered stroke cases instead of TIA, regardless of duration of symptoms, implying that optimal diagnostic methods need to be utilized. We therefore postulated that perfusion-weighted MR imaging (PW imaging) would be useful in the diagnosis of TIA. METHODS: Retrospective analysis of 22 patients with reversible neurologic symptoms lasting less than 24 hours, assessed with DW and PW imaging. RESULTS: MR imaging was abnormal in 15 patients (68%): 12 had abnormal DW imaging, four had both DW and PW imaging defects (all with a mismatch) and three had an isolated PW imaging abnormality. There were no differences in symptom duration, stroke etiology or cardiovascular risk factors between patients with abnormal MR imaging and those with unremarkable scan. Patients with mismatch were more likely to need conventional angiography or other cerebrovascular procedures. CONCLUSION: The combined use of DW imaging and PW imaging provided evidence of brain ischemia in most patients with clinical diagnosis of TIA. Prospective studies using follow-up MR imaging are required to determine the outcome of affected tissue, as well as the clinical implications of DW-PW imaging abnormalities.     

ACR Appropriateness Criteria Head Trauma

Neuroimaging plays an important role in the management of head trauma. Several guidelines have been published for identifying which patients can avoid neuroimaging. Noncontrast head CT is the most appropriate initial examination in patients with minor or mild acute closed head injury who require neuroimaging as well as patients with moderate to severe acute closed head injury. In short-term follow-up neuroimaging of acute traumatic brain injury, CT and MRI may have complementary roles. In subacute to chronic traumatic brain injury, MRI is the most appropriate initial examination, though CT may have a complementary role in select circumstances. Advanced neuroimaging techniques are areas of active research but are not considered routine clinical practice at this time. In suspected intracranial vascular injury, CT angiography or venography or MR angiography or venography is the most appropriate imaging study. In suspected posttraumatic cerebrospinal fluid leak, high-resolution noncontrast skull base CT is the most appropriate initial imaging study to identify the source, with cisternography reserved for problem solving.The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.     

Lumbar root compression in the lateral recess: MR imaging,conventional myelography,and CT myelography comparison with surgical confirmation

BACKGROUND AND PURPOSE: Previous authors have shown that conventional myelography is superior to plain CT in the assessment of root compression in the lateral recess, but this question has never been evaluated with respect to MR imaging of the lumbar level. Our purpose was to assess the accuracy of MR imaging, conventional myelography, and postmyelography CT (CT myelography) of the lumbar level in identifying degenerative lateral recess root compression with surgical confirmation. METHODS: MR imaging, conventional myelography, and CT myelography of the lumbar level were assessed in the imaging of 58 lateral recesses at 38 lumbar levels in 26 patients who underwent surgery for radiculopathy with degenerative lateral recess abnormality. Each lateral recess was graded as normal, small without root compression, small with root compression, or severe root compression. RESULTS: MR imaging underestimated root compression in 28% to 29% of the cases in which root impingement was surgically confirmed. Conventional myelography underestimated root compression in only 5% to 7% of the cases and correctly predicted impingement in 93% to 95%. CT myelography underestimated root compression in 38% of the surgically confirmed cases. CONCLUSION: MR imaging significantly underestimated root compression caused by degenerative changes in the lateral recess. Although MR imaging is a superb study when used in the search for degenerative disk disease and disk protrusion, conventional myelography is a crucial supplemental study that is necessary to confirm degenerative root impingement in the lateral recess as the cause of radiculopathy.     

Changes in CT utilization between 1981 and 1984: implications for Medicare payment for MR imaging under the prospective payment system

In the absence of data on current or likely patterns of use of magnetic resonance (MR) imaging, use of computed tomography (CT) at one institution in 1981 and 1984 was analyzed to provide data relevant to current federal deliberations regarding Medicare payment for inpatient MR imaging. Between 1981 and 1984 inpatient CT utilization increased 59%, primarily due to a 265% increase in body CT. In 1984 inpatients who underwent at least one CT procedure were as likely to undergo more than one procedure as to undergo only one. CT procedures were performed in a high proportion of diagnosis-related groups (DRGs), with more than one-half of head CT procedures performed in non-neurologic DRGs. Given the similarities between clinical applications of CT and MR imaging, these findings regarding CT utilization have the following implications: (a) a delay in recalibration of DRG payment rates may not take account of expected growth in utilization of MR imaging, (b) a DRG "add-on" for MR imaging should reflect the likelihood that more than one MR imaging procedure will be performed in many hospitalizations, and (c) adjustments in DRG payments for MR imaging should not be limited to the 35 neurologic DRGs.     

Tectorial membrane injury: frequently overlooked in pediatric traumatic head injury

REHs and tectorial membrane injuries are rare complications of pediatric head and neck injuries. We aim to describe the neuroimaging findings in pediatric REHs, to summarize the mechanism of injury, and to correlate the imaging findings with the clinical presentation. We retrospectively evaluated CT and/or MR imaging studies of 10 children with traumatic REH. Most patients were involved in MVAs. The tectorial membrane was injured in 70% of patients, and REHs were medium to large in 80%. None of the patients had a focal spinal cord or brain stem injury, craniocervical junction dislocation, or vertebral fractures. Tectorial membrane disruption was diagnosed in most patients without craniocervical junction-related symptoms. Tectorial membrane lesions and REHs were seen in young children who sustained high-speed head and neck injuries. Clinical symptoms may be minimal or misleading. The radiologist should be aware of these injuries in children. MR imaging appears to be more sensitive than CT.     

头颈部CT血管成像数据的综合应用

目的:探讨头颈部血管成像检查同时行血管周围组织器官成像的应用价值.方法:对30例可疑颈动脉狭窄的患者进行16层螺旋CT头颈部血管成像检查,除常规血管成像外,并行颈椎、颈部软组织、颅脑、副鼻窦成像.结果:30例患者发现15例颈椎椎体骨质增生,10例颈椎间盘突出,6例甲状腺瘤,8例腔隙性脑梗死,2例透明隔囊肿,5例副鼻窦炎.结论:16层螺旋CT头颈部血管成像检查不仅可以清晰显示头颈部血管,而且对血管周围组织器官病变的显示也有很高的价值.     

Incorporating patient-centered outcomes in the analysis of cost-effectiveness: imaging strategies for renovascular hypertension

OBJECTIVE: Our aim was to assess the contribution of patient-centered short-term disutilities and quality-of-life measures in the cost-effectiveness analysis of CT angiography, MR angiography, and conventional angiography in patients with medication-resistant hypertension. MATERIALS AND METHODS: A decision analytic model compared the life expectancy and incremental cost per life year using three initial diagnostic tests in a cohort of hypothetical individuals with medication-resistant hypertension over a range of renal artery stenosis probabilities: CT angiography (sensitivity, 96%; specificity, 96%; cost, $865); MR angiography (98%, 94%, $850); and conventional angiography (99%, 99%, $2,627). All imaging strategies were compared with a base case scenario mimicking the natural history of medication-resistant hypertension and with a scenario immediate enhanced medical therapy without prior imaging. Individuals without evidence of renal artery stenosis on initial testing underwent conventional angiography if enhanced medical therapy failed to control hypertension. Individuals diagnosed with renal artery stenosis on MR angiography required conventional angiography for definitive stent treatment ($11,1223). Blood pressure response to renal artery stenting or enhanced medical therapy varied according to blood pressure, as did the incidence of myocardial infarction and stroke resulting from hypertension. Patients who progressed to end-stage renal disease received dialysis ($60,000 per year). Quality-of-life adjustments were made for patients with hypertension, end-stage renal disease, myocardial infarction, and stroke. Short-term disutilities from undergoing an imaging test were included. The analysis accounted for direct costs derived from Medicare reimbursements and total costs derived from the literature. RESULTS: All imaging strategies were cost-effective compared with enhanced medical therapy alone or with natural history. When only direct costs were considered, MR angiography was the preferred strategy, with conventional angiography as a cost-effective alternative to MR angiography. When total costs were considered, conventional angiography dominated all other strategies. Adjusting for quality of life decreased the incremental cost-effectiveness ratios, making an already competitive strategy a more favorable alternative to the base case. Adjusting for test-related disutility did not significantly influence the cost-effectiveness of any of the imaging tests. Despite marked variation in the key clinical and cost variables, MR angiography remained the most cost-effective strategy. CONCLUSION: In the evaluation and treatment of medication-resistant hypertension, strategies that included preliminary imaging saved more lives than did the immediate institution of enhanced medical therapy at a lesser cost.     

Preoperative Evaluation of Cervical Radiculopathy and Myelopathy by Surface-Coil MR Imaging

During a 2-year period, 256 patients were screened for cervical radiculopathy and myelopathy with surface-coil MR images and plain films. Selected patients had follow-up examinations including CT, myelography, and CT myelography. Thirty-four of these patients underwent cervical spine surgery after MR imaging, which disclosed a total of 50 abnormalities in three major categories: herniated disks, bony canal stenoses, and intradural lesions. MR correctly predicted 88% of all surgically proved lesions compared with 81% for CT myelography, 58% for myelography, and 50% for CT. Missed herniated disks on either MR or CT myelography usually were the result of technically suboptimal studies caused by motion artifacts on MR and beam-hardening artifacts on CT myelography. Small osteophytes adjoining herniated disks sometimes were not predicted on MR, although such osteophytes invariably were seen on plain films and were palpable during standard anterior cervical diskectomy procedures. Herniated disks in the lateral root canals found in two patients appeared to be detected more readily by CT myelography than by MR. All proved lesions were detected by either screening MR images and plain films or by follow-up CT myelograms. MR replaced invasive evaluations by myelography and CT myelography in 32% of preoperative patients.We conclude that MR images, combined with plain films, offer an accurate, noninvasive test for the preoperative evaluation of cervical radiculopathy and myelopathy, while CT myelography is the preferred follow-up examination.     

Preoperative evaluation of cervical radiculopathy and myelopathy by surface-coil MR imaging

During a 2-year period, 256 patients were screened for cervical radiculopathy and myelopathy with surface-coil MR images and plain films. Selected patients had follow-up examinations including CT, myelography, and CT myelography. Thirty-four of these patients underwent cervical spine surgery after MR imaging, which disclosed a total of 50 abnormalities in three major categories: herniated disks, bony canal stenoses, and intradural lesions. MR correctly predicted 88% of all surgically proved lesions compared with 81% for CT myelography, 58% for myelography, and 50% for CT. Missed herniated disks on either MR or CT myelography usually were the result of technically suboptimal studies caused by motion artifacts on MR and beam-hardening artifacts on CT myelography. Small osteophytes adjoining herniated disks sometimes were not predicted on MR, although such osteophytes invariably were seen on plain films and were palpable during standard anterior cervical diskectomy procedures. Herniated disks in the lateral root canals found in two patients appeared to be detected more readily by CT myelography than by MR. All proved lesions were detected by either screening MR images and plain films or by follow-up CT myelograms. MR replaced invasive evaluations by myelography and CT myelography in 32% of preoperative patients. We conclude that MR images, combined with plain films, offer an accurate, noninvasive test for the preoperative evaluation of cervical radiculopathy and myelopathy, while CT myelography is the preferred follow-up examination.     

Predicting High-Flow Spinal CSF Leaks in Spontaneous Intracranial Hypotension Using a Spinal MRI-Based Algorithm: Have Repeat CT Myelograms Been Reduced?

BACKGROUND AND PURPOSE:We adopted an imaging algorithm in 2011 in which extradural fluid on spinal MR imaging directs dynamic CT myelography. We assessed algorithm compliance and its effectiveness in reducing repeat or unnecessary dynamic CT myelograms.MATERIALS AND METHODS:CT myelograms for CSF leaks from January 2011 to September 2014 were reviewed. Patients with iatrogenic leaks, traumatic brachial plexus injuries, or prior CT myelography within 2 years were excluded. Completion and results of spinal MR imaging, CT myelographic technique, and the need for repeat CT myelography or unnecessary dynamic CT myelograms were recorded.RESULTS:The algorithm was followed in 102 (79%) of 129 patients. No extradural fluid was detected in 75 (74%), of whom 70 (93%) had no leak, 4 (5%) had a slow leak, and 1 (1%) had a fast leak. Extradural fluid was detected in 27 (26%): 24 (89%) fast leaks, 1 (4%) slow leak, and 2 (7%) with no leaks. When the algorithm was followed, 1 (1%) required repeat CT myelography and 3 (3%) had unnecessary dynamic CT myelograms. The algorithm was breached in 27 (21%) cases, including no pre-CT myelogram MR imaging in 11 (41%), performing conventional CT myelography when extradural fluid was present in 13 (48%), and performing dynamic CT myelography when extradural fluid was absent in 3 (11%). Algorithm breaches resulted in 4 (15%) repeat CT myelograms and 3 (12%) unnecessary dynamic CT myelograms, both higher than with algorithm compliance.CONCLUSIONS:Using spinal MR imaging to direct CT myelography resulted in significant reduction in repeat CT myelograms to localize fast leaks with minimal unnecessary dynamic CT myelograms.

Extradural fluid on spinal MR imaging has been reported to predict fast spinal CSF leaks for which the leak site may not be localized on conventional CT myelograms (CTMs).¹ We adopted an imaging algorithm in January 2011 for the evaluation of patients with clinical suspicion of spinal CSF leak. The first step of this algorithm is to perform MR imaging of the entire spinal canal, and the results of the MR imaging are then used to guide the type of CTM initially performed. Specifically, if extradural fluid is present on MR imaging, dynamic CTM is performed. Our current technique used for dynamic CTM has been previously reported.² If extradural fluid is not present, conventional CTM is performed.The goal of adopting this algorithm was to attempt to reduce the number of repeat dynamic CTMs for leak localization in patients with fast spinal CSF leaks who initially underwent conventional CTM with the leak identified but not localizable. Averaged over the previous 8 years, repeat dynamic CTM for leak localization was performed in 21% of patients at our institution.¹ Reducing repeat CTM is desirable for several reasons, including radiation reduction, cost savings, and fewer invasive procedures.The purpose of this study was to retrospectively evaluate our compliance with the algorithm and determine its effectiveness in reducing repeat dynamic CTM performed for leak localization.     

MR angiography of the head and neck: value of two-dimensional phase-contrast projection technique.

MR angiography is commonly performed by using two- and three-dimensional time-of-flight and three-dimensional phase-contrast techniques. These procedures require long examination times and processing of imaging data by computing maximum intensity projections. Two-dimensional phase-contrast projection angiography has neither of these disadvantages. We analyzed the value of this technique for head and neck MR angiography in 84 patients and 15 control subjects. Patients were examined to resolve specific clinical questions such as the presence of arteriovenous malformations (20 cases), patency of carotid and vertebral arteries (35 cases), patency of the superior sagittal sinus (14 cases), patency of saphenous vein bypass grafts (11 cases), and vascularity of masses (four cases). Conventional angiograms were available for correlation in 22 patients. Two-dimensional phase-contrast projection angiograms were generated by using a gradient-recalled-echo sequence sensitized to flow with the use of flow-encoding gradients. Projection MR angiograms were obtained in approximately 3.5 min by combining images obtained with flow-encoding gradients applied along the axes defining the image plane. MR angiograms were subjectively evaluated by three observers without reference to routine MR images or conventional angiograms. High-quality studies were obtained in 93% of control subjects and 90% of patients examined. The findings based on phase-contrast angiography were confirmed with conventional angiography in 21 of 22 patients for whom conventional angiograms were available. Evaluation of vascular grafts and of the patency of major cranial vessels was easily done with two-dimensional phase-contrast angiography and was useful in postoperative follow-up examinations. We also advocate its use for superior sagittal sinus thrombosis and follow-up examinations in patients with arteriovenous malformations.     

Cervical myelopathy: a comparison of magnetic resonance and myelography

Fifty-seven patients with a strong clinical suspicion of cervical myelopathy were studied with body coil magnetic resonance (MR) and conventional myelography or CT myelography. Eight patients were believed to have normal studies with both modalities. There were six patients with syringomyelia; four with an intramedullary tumor; one with an arteriovenous malformation; 19 with cervical spondylosis at multiple levels; eight with cervical spondylosis at a single level; four with extensive rheumatoid arthritis; four with extradural neoplasm; two with trauma; and one patient with an epidural abscess. In this study, body coil MR was the superior examination for the evaluation of an intramedullary process. It was as diagnostic as myelography in one case of an extramedullary intradural lesion. In patients with extradural disease, body coil MR was the superior study in 45%, equivalent to myelography in 37%, and, although still diagnostic, inferior to myelography in 17%. In 8% of the cases, body coil MR was at best equivocal, whereas myelography was diagnostic. It appears that in technically adequate studies, MR is at least equivalent to myelography in its ability to delineate disease. A superior MR study provides a better appraisal of the size and character of the spinal cord as well as the degree of both anterior and posterior defects on the subarachnoid space and neural structures. In addition, MR is as good as conventional myelography for the identification of extrinsic cervical cord lesions producing cervical myelopathy. Finally, an additional small group of 30 patients were studied with a prototype surface coil to determine its advantages relative to body coil imaging. Each patient had correlative myelography. As with body coil MR, imaging with the surface coil was believed to be more informative than conventional myelography in four patients with intramedullary lesions. The remaining 26 patients suffered from cervical spondylosis. Surface coil MR was believed to be more informative than myelography in six cases (23%), equivalent to myelography in 19 (73%), and less diagnostic than myelography in one (4%). The improved spatial resolution with the use of the surface coil was believed to increase the accuracy of MR.     

Nationwide trends in rates of utilization of noninvasive diagnostic imaging among the Medicare population between 1993 and 1999

PURPOSE: To determine current utilization rates and recent nationwide trends for noninvasive diagnostic imaging (NDI) among the Medicare population. MATERIALS AND METHODS: Medicare Part B claims data files from 1993, 1996, and 1999 were analyzed for all procedure codes related to NDI. NDI codes were grouped into 22 imaging categories, as well as seven imaging modality groups. The data were analyzed to determine the overall nationwide utilization and relative value unit (RVU) volume and rates and changes in utilization rates and RVU rates between 1993 and 1999 for the Medicare fee-for-service population, which included approximately 33 million enrollees per year. RESULTS: The overall utilization rate for all NDI in 1999 was 324,974 examinations per 100,000 enrollees. Conventional radiography was the most utilized imaging technology (55.5%), followed by ultrasonography (US) (20.5%), computed tomography (CT) (8.8%), mammography (6.0%), nuclear imaging (5.2%), magnetic resonance (MR) imaging (2.6%), and bone densitometry (1.5%) (percentages do not add up to 100% due to rounding). In the 6-year interval from 1993 to 1999, the rate of NDI utilization increased 3.8%. The utilization rate for conventional radiography decreased 13.7%, while that of all other modalities increased a combined total of 39.1%. During this 6-year period, RVU rates per 100,000 increased 14.6%, with RVUs for MR imaging increasing 76.6%; those for nuclear imaging, 38.7%; those for CT, 28.3%; and those for US, 24.2%. CONCLUSION: A 3.8% increase in the rate of NDI utilization occurred during the 6-year period between 1993 and 1999. A considerably larger increase in RVU rates (14.6%) occurred during the same time period.     

Evaluation of the role of magnetic resonance myelography in lumbar spine imaging

The purpose of our study was to evaluate the accuracy of MR myelography in depicting disc herniation in the lumbar spine when compared with conventional MRI in patients presenting with clinical evidence of disc herniation. One hundred patients referred for conventional MR imaging of the lumbar spine also had coronal MR (TR 9000 ms, TE 272 ms eff, NEX 3, echo train length 32) myelography performed. Three experienced observers compared magnetic resonance myelography (MRM) with conventional lumbar spine MR using the following variables: visibility of thecal sac and nerve roots, and the presence, location and severity of disc herniation. Disc protrusions were seen at 110 disc space levels on conventional MR images as opposed to 93 on MRM. However, only 72 % of lesions seen on conventional MR were diagnosed by MRM. Similarly, only 63.8 % of nerve root compression abnormalities seen at conventional MR were visualized when compared with conventional MRM. The sensitivity, specificity and accuracy of MRM when compared with conventional MR was 72, 93 and 85 %, respectively. The MRM technique yields images that resemble conventional myelography and may be used to help confirm abnormalities seen on conventional MR in selected cases; however, the large number of false-positive and false-negative examinations indicates that caution should be used in interpreting MRM images. Received: 16 February 1998; Revision received: 25 May 1998; Accepted: 30 September 1998     

Comparison of MR and CT myelography in imaging the cervical and thoracic spine

MR imaging and CT myelography were compared in a retrospective study of 38 patients with suspected lesions of the cervical and thoracic spinal canal and cord. Twenty-eight abnormal cases were found, including spondylosis (9), tumors (8), intramedullary cavities (3), arachnoiditis (3), disk-space-centered infection or osteomyelitis (2), nonneoplastic cord swelling (2), and CSF-borne metastasis (1). MR was equal or superior to CT myelography in depicting cases of cord enlargement, cord compression, and cord atrophy, providing better tissue characterization, no shoulder artifact, and no limitation caused by CSF block. CT myelography was superior to MR in depicting cases of spondylosis and arachnoiditis. It showed superior spatial resolution, which was most pronounced when comparing axial images and hence particularly superior in detecting the lateral extent of disk herniation. Use of surface coils and thin imaging sections is essential for accurate and complete MR evaluation of the cervical and thoracic spine.     

Comparison of CT and MR imaging for the detection of extranodal neoplastic spread in metastatic neck nodes

PURPOSE: To compare computed tomography (CT) and magnetic resonance (MR) imaging for the detection of extranodal neoplastic spread (ENS) in metastatic cervical nodes from head and neck squamous cell carcinoma. MATERIALS AND METHODS: 17 patients with a squamous cell carcinoma of the head and neck underwent CT and MR imaging. The neck nodes were assessed for ENS and the results compared using pathology from the surgical resection. RESULTS: Radiologic-pathologic correlation was performed in 51 malignant nodes. The accuracy, sensitivity and specificity were respectively 73, 65, 93% for CT, and 80, 78, 86% for MR imaging. Comparison of CT and MR imaging showed that there was no significant difference between the two modalities for either sensitivity (P = 0.1317) or specificity (P = 0.3173). CONCLUSION: CT and MR imaging are comparable for the detection of ENS.     

Alveolar soft-part sarcoma of the head and neck: clinical and imaging features in five cases

BACKGROUND AND PURPOSE: Alveolar soft-part sarcoma (ASPS) of the head and neck is an extremely rare malignancy. Although the clinical and imaging features of this tumor have been reported, a periodic review of unusual tumors is useful. The purpose of this study was to describe the clinical and imaging features of ASPS of the head and neck. METHODS: Between January 1990 and May 2004 at our institution, five head and neck ASPS were diagnosed in five patients (two male and three female patients; age range, 4-22 years). Clinical and imaging findings were reviewed retrospectively. Imaging studies consisted of contrast material-enhanced CT (in four patients), MR imaging (in four patients), and digital subtraction angiography (in two patients). RESULTS: The locations of the tumor were tongue in two cases, larynx in one case, buccal space in one case, and paravertebral space in one case. This tumor appeared as a large lobulating-contoured mass with high signal intensity and flow voids on T2-weighted images and showed strong enhancement on contrast-enhanced CT and MR images. Preoperative angiography showed high vascularity. Wide surgical excisions were performed in four cases. Mean follow-up periods were 16 months (range, 6-30 months), and no recurrence was noted except for the laryngeal case. CONCLUSION: ASPS should be included in the differential diagnosis of head and neck tumor when a slow-growing, large mass with high signal intensity and flow voids on T2-weighted images and strong enhancement on contrast-enhanced CT or MR image is seen, particularly in young female patients.     

Neurosyphilis in HIV-positive and HIV-negative patients: neuroimaging findings.

PURPOSETo evaluate and describe the neuroimaging findings of patients with neurosyphilis.METHODSThe neuroimaging studies of 35 patients with documented neurosyphilis were reviewed. Diagnosis was established in 34 patients with cerebrospinal fluid for a Venereal Disease Research Laboratory test, complemented by autopsy in 1 and brain biopsy in 1. All patients had reactive fluorescent treponemal antibody tests with absorption in their sera. Imaging studies included plain and contrast-enhanced CT of the brain, plain and gadolinium-enhanced MR, MR angiography, and conventional angiography. Imaging findings were also correlated with the relevant pathologic findings at autopsy in three additional patients with neurosyphilis who did not have brain imaging studies.RESULTSOf the 35 patients with imaging studies, 32 tested human immunodeficiency virus (HIV)-seropositive, and 3 were HIV-seronegative. Eleven (31%) of 35 patients had normal radiographic findings. Cerebral infarctions were seen in 8 (23%) of 35 patients, and nonspecific white matter lesions in 7 (20%) of 35. Cerebral gummas and extraaxial enhancement indicating meningitis were noted in 2 (6%) of 35 patients, respectively. Arteritis was demonstrated in 2 (50%) of 4 patients who underwent either MR angiography or conventional angiography. The 3 subjects who had autopsy but not imaging studies were found to have manifestations of meningovascular syphilis, including syphilitic leptomeningitis and an obliterative endarteritis.CONCLUSIONWe conclude that findings of vascular occlusive disease manifested as infarction or arteritis, enhancing cortical lesions with or without adjacent meningeal enhancement, focal or diffuse extraaxial enhancement, and white matter disease, although nonspecific, in the proper clinical setting should prompt appropriate testing for neurosyphilis, a treatable disease, in patients with and without HIV infection.