Prognosis Evaluation of MRI Combined with Magnetic Resonance Myelography on Lumbar Disc Herniation after Transforaminal Endoscopic Discectomy.

OBJECTIVE: This study sets out to investigate the role of magnetic resonance imaging (MRI) combined with magnetic resonance myelography (MRM) in patients after percutaneous transforaminal endoscopic discectomy (PTED) and to evaluate its value in postoperative rehabilitation. METHODS: The clinical date of 96 patients with lumbar disc herniation (LDH) after PTED was retrospectively analyzed. The enrolled patients were divided into MRI group (n = 32) and MRI + MRM group (n = 64) according to whether MRM was performed. The nerve root sleeve (morphology, deformation) and dural indentation, intervertebral space height (ISH), intervertebral space angle (ISA), degree of pain (Visual Analogue Scale (VAS)), vertebral function (Japanese Orthopaedic Association (JOA)), and long-term recurrence were compared between the two groups. RESULTS: Compared with the MRI group, the MRI + MRM group better displayed nerve root morphology, sheath sleeve deformation, and dural indentation. Both MRI and MRI + MRM showed ISH and ISA changes well. Compared with the MRI group, the MRI + MRM group had a significantly lower VAS score for lumbar and leg pain, a significantly higher JOA score, and a significantly lower 2-year recurrence rate. CONCLUSION: MRM combined with MRI is more beneficial to improve the prognosis of LDH patients after PTED.

Clinical usefulness of CT-myelogram comparing with the MRI in degenerative cervical spinal disorders: is CTM still useful for primary diagnostic tool?

STUDY DESIGN: A radiographic review of 50 patients (29 radiculopathy and 21 myelopathy) who had undergone the anterior cervical discectomy and fusion was performed by 3 observers retrospectively. OBJECTIVE: To compare the accuracy between magnetic resonance imaging (MRI) and postmyelographic computed tomography (CTM) in degenerative cervical spine disease by assessing the degree of interobserver and intraobserver agreement. SUMMARY OF BACKGROUND DATA: The assessment of degenerative cervical spinal disease is still demanding. Now MRI is accepted as a primary diagnostic tool for degenerative cervical spine disease. Compared with MRI, usage of CTM has diminished, but it is usually reserved for the patients for whom MRI results were ambiguous or technically suboptimal. METHODS: We retrospectively reviewed MRIs and CTMs of 50 patients (29 radiculopathy and 21 myelopathy) who had undergone the anterior cervical discectomy and fusion procedure. Using an assessment scale, 3 observers examined 5 parameters: spinal canal narrowing, foraminal stenosis, bony abnormality, intervertebral disk herniation, and nerve root compression. The degree of severity was graded using a 4-point scale for each item. Intraobserver, interobserver agreement, and the accentuation of each image were analyzed. RESULTS: Intraclass correlation coefficiency statistical analysis showed moderate intraobserver agreement (Cronbach's alpha=0.63) and interobserver agreement (0.52). There was no significant difference in intraobserver, interobserver agreement between MRI (0.58) and CTM (0.57). Compared between MRI and CTM, disc abnormality and nerve root compression on MRI and foraminal stenosis and bony lesion on CTM showed better agreement. CONCLUSIONS: CTM was still useful in diagnosis of the foraminal stenosis and bony lesion comparing with MRI but showed limitation in disc abnormality and nerve root compression. So even though CTM may provide valuable additional information in difficult or ambiguous cases, it also requires universal standards and sound experience for constant and objective information.

Low-Pressure Lumbar Provocation Discography According to Spine Intervention Society/International Association for the Study of Pain Standards Does Not Cause Acceleration of Disc Degeneration in Patients With Symptomatic Low Back Pain: A 7-Year Matched Cohort Study.

STUDY DESIGN: Retrospective matched cohort study. OBJECTIVE: To determine if low-pressure lumbar provocation discography (PD) results in long-term accelerated disc degeneration, internal disc disruption, or disc herniation in patients with symptomatic low back pain (LBP). SUMMARY OF BACKGROUND DATA: Study of subjects without clinically-significant LBP suggests that high-pressure PD may accelerate disc degeneration. METHODS: Consecutive patients with symptomatic LBP who underwent magnetic resonance imaging (MRI), PD, and repeat MRI more than 7 years later, but did not undergo subsequent spinal fusion surgery, were included. Punctured discs were matched (1:2 to 1:4) to corresponding discs in a control cohort by age, BMI, Pfirrmann score (±2), and presence of disc herniation; control cohort inclusion required MRIs for symptomatic LBP, separated by more than 7 years. The primary outcome of the study was a progression in Pfirrmann score category (I-II, III-IV, V). MRI disc-to-CSF T2 signal-intensity ratio, disc height, disc herniations, high intensity zones (HIZs), and Modic changes were assessed. RESULTS: Baseline and follow-up MRIs were available for 77 discs exposed to PD, and for 260 discs in the matched control cohort. There was no difference in the proportion of punctured discs that advanced in Pfirrmann score category in the PD group (17%, 95% CI 9-27%) compared with corresponding discs in the Control group (21%, 95% CI 17-27%), P = 0.3578, or in non-punctured discs in the PD group (35%, 95% CI 21-51%) compared with corresponding discs in the Control group (34%, 95% CI 27-42%), P = 0.1169. There were no differences in disc-to-CSF T2 signal-intensity ratio, presence of disc herniations, HIZs, or Modic changes following puncture in the PD versus matched cohort discs or in the non-punctured PD cohort discs versus corresponding control cohort discs (P > 0.05). CONCLUSION: Patients with symptomatic LBP who underwent low-pressure PD, but who did not undergo a subsequent spinal fusion surgery, developed disc degeneration and new disc herniations at a similar rate to corresponding discs in matched control patients. LEVEL OF EVIDENCE: 3.

Role of Conventional Myelography in Diagnosis and Treatment of Degenerative Spine Disease in Low-Income Communities: Prospective Study.

INTRODUCTION: Chronic back pain is a common problem, and imaging is crucial for effective diagnosis and treatment. In low-resource settings conventional myelography is a cheap alternative to magnetic resonance imaging and computed tomography. This study was conducted to reexamine the diagnostic reliability, effectiveness for surgical decision making, and safety of conventional myelography. METHODS: The study was conducted at Tenwek Mission Hospital during June 2009 and March 2010. New patients who presented with features of radiculopathy and/or myelopathy were eligible. Standard anteroposterior views were taken; oblique views were obtained from patients with radiculopathy. Cervical and lumbosacral myelography was performed using iohexol contrast. Patients were observed for complications. Those with surgically remediable lesions underwent operation. Patients were monitored for symptom improvement and complication postoperatively. RESULTS: Fifty-one patients underwent diagnostic myelography and 39 of them (77.8%) were positive. Lesions at levels L4/5 were the most common, occurring in 23 patients (59%). Of those with cervical lesions, 11 of them (73.3%) had a positive myelography compared with 28 patients (77.8%) with lumbosacral lesions. Patients presenting with claudication were more likely to have a positive myelography, compared with those with other symptoms. There were 16 patients (41%) with partial spinal canal block, 6 patients (15.4%) with total block, and 17 patients (43.6%) with recess compression. Thirty-eight (38) patients had surgery, and recess decompression was the most common procedure (n = 24, 63.2%). Following surgery, symptoms due to degenerative spine disease improved in the majority of patients. CONCLUSIONS: Conventional myelography is a reliable and safe diagnostic test. Appropriate and sound surgical decisions can be made following conventional myelography tests.

Shift in imaging modalities of the spine through 25 years and its impact on patient ionizing radiation doses.

STUDY DESIGN: Retrospective. OBJECTIVE: To explore the shift in modalities when diagnosing the spine in the years 1979-2003. To see how this shift, together with a radiation protective policy, have influenced on the ionizing radiation doses. SUMMARY OF BACKGROUND DATA: The shift from CT/myelography to MR when diagnosing the spine is well known. To what extent this has changed the radiation doses has to our knowledge not yet been published. METHODS: Activity reports from a department of radiology have been reviewed. Relevant radiation doses estimates have been obtained from the Norwegian Radiation Protection Authority. RESULTS: MRI was introduced in 1992 and has been used increasingly since then. Conventional X-ray to the spine has been practically unchanged. Myelography and CT decreased markedly after the introduction of MRI. The total number of examinations of the spine has increased, but the radiation doses given have decreased since 1993. CONCLUSIONS: The introduction of MRI together with a radiation protective policy have reduced the ionizing radiation doses given to this population, in spite of an increase in the total number of examinations of the spine.

Pharmacokinetics and tolerability of iopromide 240 after lumbar myelography.

OBJECTIVE: To evaluate the pharmacokinetics and tolerability of iopromide 240 mg iodine/mL after intrathecal administration. METHODS: Eleven patients with an indication for lumbar myelography received 10 mL iopromide 240 in an open, prospective, single-center study. All patients were followed 72 hours after the procedure and remained in the hospital. Urine was sampled from before the myelography up to 72 hours after the procedure in stages (range, 0-6, 6-12, 12-24, 24-48, and 48-72 hours). Iodine plasma levels were determined before and 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 9 hours, 12 hours, and 24 hours after the administration of iopromide 240. Vital signs were measured at baseline, before, and 1 and 24 hours after the procedure. Physical and neurologic examinations were performed in all patients at baseline and at the end of the study period; all adverse events were recorded. The results were subject to pharmacokinetic analysis using compartment model-independent and -dependent methods. RESULTS: Ten of 11 patients had measurable iodine plasma levels. After a lag time of approximately 0.6 hours (mean value), maximum iodine concentrations of 45% of the administered dose per total plasma volume were observed after 3.8 hours. Plasma half-lives ranged from 3.0 to 60.5 hours (model-independent methods) with a mean of 14.9 hours and a standard deviation of 17.0 hours. Using curve fitting with an open one-compartment model revealed good agreement with the model-independent methods (half-life 17.3 hours). The recovery of iodine in urine in the 72-hour period was 78%+/-15% (range, 53%-94%) as a result of an undeterminable loss of urine in some patients and prolonged half-lives in two patients. Only one patient had adverse events 24 hours after myelography. CONCLUSIONS: After lumbar myelography, iopromide 240 is almost completely excreted renally within 72 hours, with a prolonged half-life as a result of the route of administration. The kinetics of iopromide 240 after intrathecal administration are characterized by a prolonged half-life. The safety of the contrast medium was confirmed.

Use trends and geographic variation in neuroimaging: nationwide medicare data for 1993 and 1998.

BACKGROUND AND PURPOSE: Powerful tools, including CT and MR imaging, have revolutionized neuroimaging. These are routinely used, but the extent and variation of use has not been studied. Our purposes were to determine the use rates of MR imaging and CT (of spine, brain, or head and neck), myelography, conventional angiography, and MR angiography in diagnosing neurologic disorders; to study trends in use; and to determine regional variations in use. METHODS: We used the National Part B Medicare Database for 1993 and 1998 to compare rates of use for these procedures in 10 geographic regions. RESULTS: In 1993 and 1998, respectively, 13,897 and 19,431 (39.8% increase) neuroimaging procedures were performed per 100,000 Medicare beneficiaries nationwide. Use of brain or head and neck CT (30.4%) and MR imaging (43.6%), spinal CT (3.5%) and MR imaging (83.0%), myelography (56.6%), and conventional angiography (24.3%) increased in 1998 versus 1993. Increases in MR angiography were not assessed, because this procedure was not reimbursable in 1993. Regional use of brain or head and neck and spinal CT and MR studies varied considerably; ratios of highest and lowest rates were 1.38-1.56. Use of MR angiography, myelography, and conventional angiography varied three- to fourfold. CONCLUSION: Use of MR and CT studies of the brain or head and neck and of the spine increased considerably in the Medicare population between 1993 and 1998. Use of conventional invasive procedures such as myelography and angiography increased strikingly, contrary to the expected decline. Regional use varied substantially.

Low back pain hospitalization. Recent United States trends and regional variations.

STUDY DESIGN: This study describes recent United States trends and regional variations in the management of low back pain. OBJECTIVES: The authors investigated recent temporal trends and compared practices in different geographic regions. SUMMARY OF BACKGROUND DATA: Controversy exists concerning the appropriate medical and surgical management of patients with low back pain. METHODS: National Hospital Discharge Survey data from 1979 through 1990 were analyzed. Case selection was based on previously developed algorithms intended to exclude nonmechanical causes of back pain. RESULTS: Over the period of study, nonsurgical hospitalizations for low back pain decreased dramatically. In contrast, low back operation rates, particularly for fusion surgery, increased substantially. In recent years, surgery and hospitalization rates were highest in the South and lowest in the West. CONCLUSIONS: Rapidly increasing surgical rates and wide geographic variations suggest the need for a more consistent approach to back problems.

A study and analysis of spinal canal diseases in the Black Lion Hospital by myelography.

Sixty seven lumbar and thoracic myelographic examinations were performed during the period February 1987 to September 1988. Fourteen patients (21%) had normal myelography while 53 (79%) patients had pathological findings. Spinal canal tumours accounted for the majority of complete CSF blocks (76.7%) Seventy-five per cent of the intradural tumours showed no abnormality on plain films of the vertebral column, whereas 75% of the extradural tumours had pathological findings. Dorsal (central) disc herniation was more frequent (70%) than lateral herniation with almost equal distribution at L5-S1 and L4-L5 disc spaces. Central disc herniation was more common at L4-L5 (71%). The measurement of the interpedicular distance on plain radiograph was not found to be diagnostic in our single case of spinal stenosis.

Technical compliance to standard guidelines for lumbar puncture and myelography: survey of academic neuroradiology attendings and fellows.

RATIONALE AND OBJECTIVES: To assess technical compliance among neuroradiology attendings and fellows to standard guidelines for lumbar puncture and myelography to minimize procedural complications such as iatrogenic meningitis and spinal headache. MATERIALS AND METHODS: We surveyed academic neuroradiology attendings and fellows in the e-mail directory of the Association of Program Directors in Radiology. We queried use of face masks, use of noncutting needles, and dural puncture practices. All data were collected anonymously. RESULTS: A total of 110 survey responses were received: 75 from neuroradiology attendings and 34 from fellows, which represents a 14% response rate from a total of 239 fellows. Forty-seven out of 101 (47%) neuroradiologists do not always wear a face mask during myelograms, and 50 out of 105(48%) neuroradiologists do not always wear a face mask during lumbar punctures, placing patients at risk for iatrogenic meningitis. Ninety-six out of 106 neuroradiologists (91%) use the Quincke cutting needle by default, compared to only 17 out of 109 neuroradiologists (16%) who have ever used noncutting needles proven to reduce spinal headache. Duration of postprocedure bed rest does not influence incidence of spinal headache and may subject patients to unnecessary monitoring. Only 15 out of 109 (14%) neuroradiologists in our study do not prescribe bed rest. There was no statistically significant difference in practice between attendings and fellows. CONCLUSIONS: Iatrogenic meningitis and spinal headache are preventable complications of dural puncture that neuroradiologists can minimize by conforming to procedural guidelines. Wearing face masks and using noncutting spinal needles will reduce patient morbidity and lower hospitalization costs associated with procedural complications.

When should I do dynamic CT myelography? Predicting fast spinal CSF leaks in patients with spontaneous intracranial hypotension.

BACKGROUND AND PURPOSE: Some patients with SIH have fast CSF leaks requiring dynamic CTM for localization; however, patients generally undergo conventional CTM before a dynamic study. Our aim was to determine whether findings on head MR imaging, spine MR imaging, or opening pressure measurements can predict fast spinal CSF leaks. MATERIALS AND METHODS: A retrospective review was performed on 151 consecutive patients referred for CTM to evaluate for spinal CSF leak. Head MR imaging was evaluated for diffuse dural enhancement and "brain sag," and spine MR imaging for presence of an extradural fluid collection. The opening pressure was recorded. The CTM was scored as no leak, slow leak localized on conventional CTM, or fast leak that required dynamic CTM. RESULTS: Fast CSF leaks were identified in 32 (21%), slow leaks in 36 (24%), and no leak in 83 (55%) of 151 patients on initial CTM. There was significant association between spinal extra-arachnoid fluid on MR imaging and the presence of a fast leak (sensitivity 85%, specificity 79%, P < .0001). There was not significant association between fast leak and findings on head MR imaging (P = .27) or opening pressure (P = .30). CONCLUSIONS: If all patients with spinal extra-arachnoid CSF on MR imaging had been sent directly to dynamic CTM, repeat myelography would have been avoided in most patients with fast leaks (23 of 27; 85%). However, a minority of patients with slow or no leaks would have been converted from conventional to dynamic CTM (16 of 77; 21%). Spinal MR imaging is helpful in premyelographic evaluation of SIH.

Reduction of contractility and reactivity in isolated lymphatics from hemorrhagic shock rats with resuscitation

PURPOSE: To evaluate the changes of contractility and reactivity in isolated lymphatics from hemorrhagic shock rats with resuscitation. METHODS: Six rats in the shock group suffered hypotension for 90 min by hemorrhage, and resuscitation with shed blood and equal ringer's solution. Then, the contractility of lymphatics, obtained from thoracic ducts in rats of the shock and sham groups, were evaluated with an isolated lymphatic perfusion system using the indices of contractile frequency (CF), tonic index (TI), contractile amplitude (CA) and fractional pump flow (FPF). The lymphatic reactivity to substance P (SP) was evaluated with the different volume of CF, CA, TI and FPF between pre- and post-treatment of SP at different concentrations. RESULTS: The CF, FPF, and TI of lymphatics obtained from the shocked rats were significantly decreased than that of the sham group. After SP stimulation, the ∆CF (1×10-8, 3×10-8, 1×10-7, 3×10-7 mol/L), ∆FPF (1×10-8, 3×10-8, 1×10-7 mol/L), and ∆TI (1×10-8 mol/L) of lymphatics in the shock group were also obviously lower compared with the sham group. In addition, there were no statistical differences in CA and ∆CA between two groups. CONCLUSION: Lymphatic contractility and reactivity to substance P appears reduction following hemorrhagic shock with resuscitation. .

Are C1-2 punctures for routine cervical myelography below the standard of care?

BACKGROUND AND PURPOSE: Recently, the performance of C1-2 punctures for cervical myelography was challenged in a medicolegal proceeding as being below the standard of care. We sought to examine current neuroradiologic practices and opinions on the technique. MATERIALS AND METHODS: An 11-question survey was sent to 120 program directors of neuroradiology via e-mail links regarding cervical myelography using a C1-2 puncture. Reminders were sent during a 2-month period before data were finalized. RESULTS: Eighty-five of 120 (71%) surveys were returned. In the previous year, 14.3% (12/85) of institutions had not performed a C1-2 puncture. Thirty-eight percent (32/85) had performed >or=6 in the same period. Seventy-nine percent (54/68 responding) favored a lumbar approach to cervical myelography, with 6% (4/68) having a predilection for a C1-2 puncture. Ninety-five percent (76/80 responding) thought that performing a C1-2 puncture for cervical myelography reflected the standard of care. Every institution except 1 had staff with expertise to perform C1-2 punctures, and 73% of the institutions teach their fellows the procedure. Ninety-three percent (78/84) of programs would perform a C1-2 puncture for thoracolumbar pathology if MR imaging was contraindicated and there was a contraindication such as a local wound infection precluding a lumbar puncture. Indications for a C1-2 approach included severe lumbar spinal stenosis, infection in the lumbar region, upper limit of the block to be delineated, technical issues preventing lumbar puncture, and the best assessment of the cervical region for myelographic films. CONCLUSIONS: C1-2 puncture for cervical myelography, though currently not the most frequently performed method at most institutions, continues to be practiced and is considered within the standard of care by most neuroradiology programs across the country.

Myelographic evaluation of cervical spondylosis: patient tolerance and complications.

STUDY DESIGN: Retrospective chart review of documented adverse events in 637 consecutive patients after computed tomogram myelography and follow-up interview of the most recent 100 of these patients. OBJECTIVES: This study assessed documented prevalence of adverse events after diagnostic myelography in cervical spondylotic patients and compared with perceived adverse events and satisfaction in a subset of the same cohort of patients. SUMMARY OF BACKGROUND DATA: There are some data that suggest complimentary benefits of myelography to magnetic resonance imaging. However, given the invasive nature of myelography, there are little data documenting the adverse events and patient experience with myelography to guide informed consent and physician choice of this study. METHODS: We analyzed the records of 637 consecutive patients (364 males and 273 females) after myelography. Five hundred forty-four patients (group 1) had a cervical approach and 93 (group 2) had a lumbar approach. The last 100 consecutive patients (85 in group 1 and 15 in group 2) were asked questions that addressed patient perceived adverse reactions, pain levels, and satisfaction. RESULTS: There was a 4.4% (28/637) prevalence of documented abnormal reactions. Group 1 had a 4.9% (25/506) prevalence of adverse reactions compared with 3.4% (3/89) in group 2. Overall 6.6% (42/637) had to have their myelographic procedures converted. Group 1 had 7% (38/544) converted to the lumbar approach group 2 had 4.3% (4/93) converted to the cervical approach. Thirty percent of the 100 patients interviewed felt they had an unexpected reaction (28 group 1 and 2 group 2). When interviewed, 14% of patients had maximum pain scores of 10 during the procedure and 8% (all group 1) felt worse pain after the procedure was completed. Six group 1 and 2 group 2 patients would not have the procedure again even when recommended by the surgeon. There was no statistically significant difference between complication rates, conversion rates, or patient perceived unexpected reactions between the 2 groups (beta=0.90). CONCLUSIONS: This paper demonstrated the discrepancy between documented adverse events with computed tomogram myelography and patient reported tolerance as recorded by telephone follow-up. The cervical approach had a greater degree of patient perceived discomfort and a trend toward higher documented and patient reported adverse events and rate of approach conversion to a lumbar approach (P>0.5). When choosing myelography to evaluate patients with cervical spondylosis, the surgeon should consider the low patient tolerance and frequent adverse reactions that often go undocumented.

Myelography complications and current practice patterns.

OBJECTIVE: Relatively few data are available in the literature on postmyelography complications. Also, no consensus exists on the need to screen myelography patients for use of potentially epileptogenic drugs, metformin, and aspirin or other nonsteroidal antiinflammatory drugs (NSAIDs) or to routinely check prothrombin time (PT) and partial thromboplastin time (PTT). We designed a Web-based survey to obtain information on myelography complications and current practice patterns. MATERIALS AND METHODS: An e-mailing was sent to 2,296 members of the American Society of Neuroradiology (ASNR), requesting their participation in a survey, and 351 responses (15%) were received. The survey included questions on the number of myelography examinations performed and the number of seizures and other complications observed in myelography patients; questions on screening for potentially epileptogenic drugs, metformin, and aspirin or other NSAIDs; and a question on checking PT and PTT. RESULTS: Most responding ASNR members (88%) reported no postmyelography seizures, and 82% observed no other significant complications in the past 5 years. A majority of practitioners (63%) screens patients for potentially epileptogenic drugs, 63% of respondents do not advise patients to discontinue metformin use after myelography, 58% do not advise patients to discontinue aspirin or other NSAIDs, and 73% do not routinely check PT and PTT. CONCLUSION: Myelography is generally safe, with a low risk of seizures, contrast reactions, and other significant complications. The results of this study show that a majority of practitioners screens patients for use of potentially epileptogenic drugs, but a majority does not require patients to discontinue use of metformin and aspirin or other NSAIDs, nor do they routinely check PT and PTT before the procedure. These common practice patterns are considered to be appropriate for the safe and efficient performance of myelography.

Long term effects of the introduction of noninvasive investigations in neuroradiology. Part 2: Effects on management of individual patients.

Review of imaging investigations undergone by cohorts of in- and outpatients of a neurological hospital at 8 year intervals over a 25 year period showed that while the pattern of investigation of the individual patient was little affected by the introduction of radionuclide studies, the subsequent availability of computed tomography had a rapid and cumulative effect on the use not only of invasive investigations, but also of plain films and other noninvasive examinations.

Nonfatal adverse reactions to iodinated contrast media: spontaneous reporting to the U.S. Food and Drug Administration, 1978-1994.

PURPOSE: To identify any changes in the frequency of serious, nonfatal adverse drug events (ADEs) reported to the U.S. Food and Drug Administration in 1978-1994 since the introduction of low-osmolality contrast media (LOCM). MATERIALS AND METHODS: Reports of ADEs submitted were reviewed for use of iodinated contrast media. RESULTS: The estimated 170 million contrast medium-enhanced radiologic studies performed in 1978-1994 produced 22,785 reports of mild or moderate ADEs, 2,639 reports of serious but nonfatal ADEs, and 920 reports of death. The most common ADEs (urticaria, dyspnea, vomiting, pruritus, facial edema, and hypotension) ranked similarly for ionic and nonionic contrast media. High-osmolality contrast media were associated with 512 serious, nonfatal ADEs reported in 1978-1986; 1,068 were reported in 1987-1994. Nonionic LOCM were associated with 17 serious, nonfatal ADEs reported in 1978-1986; 609 were reported in 1987-1994. Intrathecal injection of nonionic contrast media was associated with 235 reported serious, nonfatal ADEs; intrathecal ionic [corrected] contrast media were associated with 14 such reported ADEs. CONCLUSION: Reports of serious, nonfatal ADEs are uncommon relative to the use of contrast media. The authors observed no decrease in the number of ADEs reported since the introduction of LOCM but did not consider marketing trends or secular reporting trends.

Performance of neuroradiologic examinations by nonradiologists.

PURPOSE: To determine the level of participation by nonradiologists in performing neuroradiologic examinations. MATERIALS AND METHODS: Medicare part B claims data from fiscal year 1992 were analyzed for CPT (current procedural terminology) codes related to computed tomography (CT) and magnetic resonance (MR) imaging of the brain, head and neck, and spine, as well as myelography, angiography, and diskography. Data were tabulated by place of service (hospital-based vs freestanding imaging centers) and by medical specialty. RESULTS: Among 363,224 Medicare claims for CT and MR imaging of the brain, head and neck, and spine, 91% of the examinations were performed in hospitals and 9% in offices or freestanding centers; 98% of studies were interpreted by a radiologist. The largest share of radiology billing by nonradiologists was from office-based or freestanding imaging centers (9%), versus 2% at hospital-based facilities. CONCLUSION: Radiologists perform the vast majority of neuroradiologic examinations. Most neuroradiologic examinations performed by nonradiologists are from neurologists at freestanding/office-based imaging centers.