Iohexol lumbar myelography: clinical study

Forty-three patients underwent lumbar myelography with the new, nonionic contrast medium iohexol. Multiple laboratory examinations, neurologic examinations, and electrocardiograms showed no significant alterations after intrathecal injection of the contrast agent. Mild electroencephalographic changes were seen in one patient. Nineteen adverse reactions occurred in 13 patients; only one of them was considered severe. No patient experienced a seizure, auditory or visual hallucination, or similar neuropsychologic reaction. This is a distinct improvement over the side effects described for previous water-soluble contrast agents. The adverse reactions occurring with iohexol myelography are fewer in number and less severe than with metrizamide myelography, and radiographic visualization obtained with iohexol is equal to that obtained with metrizamide. With iohexol, it appears that the most disturbing and disabling neuropsychologic reactions have been reduced to an acceptable minimum.     

Iohexol compared to metrizamide in cervical and thoracic myelography

Summary A randomized double blind study with iohexol (Omnipaque) and metrizamide (Amipaque) in cervical myelography was performed in 50 patients, 29 with iohexol and 21 with metrizamide. The myelographies were performed either with lumbar or with C₁–C₂ puncture in about equal groups, using 300 mg I/ml and 240 mg I/ml of the contrast media respectively. The image quality was equal with both contrast media, excellent in about 4/5 and good in 1/5 of the examinations. Subjective side effects were twice as frequent with metrizamide as with iohexol. The most frequent side effect was headache, occurring in 34% with iohexol and in 67% with metrizamide. Altogether 24% or the patients had EEG changes after iohexol as compared to 47% after metrizamide. All EEG changes were slight dysrythmia-except in three patients with spike activity after metrizamide. These were the only ones with mental reactions as well. It can be concluded that in this trial iohexol was better suited for cervical myelography than metrizamide.     

Metrizamide compared with iohexol for cervical myelography: a double-blind study

A double-blind comparative study of iohexol and metrizamide for use in cervical myelography through lumbar puncture was carried out in a group of 30 patients. No difference was found in the quality of radiographic examinations of the cervical or lumbar regions nor in the postmyelographic computed tomographic examinations of the cervical spine. The overall incidence of side effects was significantly higher in the metrizamide group (93.4%) than in the iohexol group (40%) (p = 0.002). The differences in incidence of nausea (53% in the metrizamide group compared with 13% in the iohexol group) and vomiting (46.6% with metrizamide, 6.6% with iohexol) were also significant (p = 0.02). Pyramidal signs and seizures occurred only after metrizamide myelography.     

Iohexol versus metrizamide for lumbar myelography: double-blind trial

Lumbar myelography was performed in 50 patients; 25 received iohexol (an investigational aqueous contrast agent) and 25 received metrizamide. The two media produced radiographs of equal quality. However, iohexol is stable in solution, while metrizamide is not. Further, markedly less morbidity resulted from iohexol. These features indicate that iohexol may be superior to metrizamide as a contrast agent for lumbar myelography.     

Iopamidol and metrizamide for myelography: prospective double-blind clinical trial

In a comparative randomized double-blind study, 73 patients underwent myelography using iopamidol (36 patients) or metrizamide (37 patients) as contrast medium. The overall diagnostic adequacy of iopamidol myelography was found to be comparable to that of metrizamide myelography. The incidence of examinations graded as superior (64%) or adequate (36%) with iopamidol was equivalent to that with metrizamide (57% superior, 43% adequate). Adverse reactions after iopamidol myelography were fewer, less severe, and generally of shorter duration than those associated with metrizamide. In the iopamidol group, adverse reactions occurred in nine (25%) patients, all of whom experienced mild or moderate headache, one with nausea, vomiting, and fatigue. In the metrizamide group, adverse reactions occurred in 17 (46%) patients, all of whom experienced mild or moderate headache, six with nausea and vomiting and four with back and leg pain. Of nine individuals who underwent myelography using 300 mg 1/ml metrizamide injected via lateral C1-C2 puncture, three experienced a toxic encephalopathy with confusion, dysphasia, headache, nausea, and vomiting, and a fourth individual suffered severe nausea, vomiting, fever, and irregular pulse. Encephalopathy was not observed in any of the 11 patients in whom myelography was performed via lateral C1-C2 puncture with a similar concentration of iopamidol. No seizures were encountered, and no clinically significant changes in laboratory studies were observed with either contrast medium.     

High-dose iohexol myelography

Lumbar myelography was performed with high volumes of iohexol (15-24 ml) at a concentration of 180 mgI/ml (average dose, 20 ml) in 48 patients. In 44 patients receiving more than the currently recommended upper dose limit of 17 ml, the frequency of headache (41%), nausea (14%), and vomiting (9%) was comparable to results for routine-dose lumbar metrizamide myelography. Overall, adverse reactions were more frequent, particularly at the highest dose levels, than reported for conventional-dose iohexol myelography. However, there were no occurrences of neuropsychiatric disorder, encephalopathy, or seizure. High-dose technique allows superior visualization of upper lumbar and conus detail and may be advantageous in patients with large subarachnoid spaces and in multi-level examinations. This study supports the results of previous trials that suggested the relative safety of iohexol as a contrast agent and extends those observations to a higher dose range. Because of the increased rate of adverse reactions at the highest dose levels (despite the absence of major adverse reactions), iohexol should continue to be used conservatively, with doses carefully tailored to each examination.     

C1-C2 myelography with iohexol and metrizamide: comparative study

Comparison of metrizamide and iohexol contrast media for myelography performed via lateral C1-C2 puncture in a total of 64 patients demonstrated superiority of iohexol with respect to the incidence of postprocedure adverse reactions. There was no significant difference between the two media in quality of radiographic demonstration in the cervical region. Patients in whom posterior fossa positive-contrast radiographic examinations were performed at the same time as myelography, using either water-soluble agent, did not demonstrate any increased incidence of side effects over those having myelography alone.     

Iohexol in paediatric myelography

Summary Iohexol was introduced by lumbar puncture in a series of 148 consecutive children aged between 5 days and 16 years referred for myelography; no patient was excluded. Initially, iohexol 180 mgI/ml was used in dosage proportional to body weight varying between 5 ml and 15 ml. During the later part of the trial concentration of iodine was increased to 240 mg/ml for cases in which the dorsal region was of particular interest (69 patients) and to 300 mg/ml for 8 cervical studies. The total dose ranged up to 4.8 g and varied between 0.03 g and 0.51 gI/kg body weight. In all patients, neurological examinations were performed before and at 24 h and observations for adverse reactions continued over a period of 48 h. The contrast medium was run up to the foramen magnum or basal cisterns in 128 patients and to the upper dorsal region in the other 20. In the first 62 patients vital studies were performed over the period of the myelogram and for 24 h following, and an additional limited neurological examination was made at 6 h, and in the first 26 cases of the series EEG's were done before and at 24 h after the myelogram. Minor variations in pulse rate and blood pressure were observed but these were not of sufficient magnitude to be of clinical significance. In 7 patients there was minor, generally slow wave abnormality on the EEG taken after the procedure, but no spike or epileptogenic activity was obserse reactions. Focal increase in neurological signs, associated with backache and probably related to the mechaniccs of lumbar puncture and myelography, occurred in 3 tumour patients; otherwise no change in neurological condition was observed in any case. Minor reactions were observed in 24 other patients (16.2%); vomiting 14 (9.5%), headache 8 (5.7%), backache 6 (4.1%), stomache ache 2 (1.5%), mild pyrexia 3 (2.0%). The incidence and severity of these reactions was considerably less than with metrizamide myelography and all resolved within 2 days of the iohexol injection. In conclusion, iohexol has significant advantages over previously used non-ionic contrast media and is suitable for paediatric myelography.     

Iohexol vs. metrizamide: study of efficacy and morbidity in cervical myelography

A double-blind study was conducted in 60 patients undergoing either cervical or more complete myelography via C1-C2 puncture. Patients received either iohexol or metrizamide at a 300 mg l/ml concentration. The contrast media were equally efficacious in the production of high-quality radiographs and CT scans. However, the incidence of adverse reactions differed markedly. Of patients receiving metrizamide, 68% had some type of adverse reaction, whereas only 26% receiving iohexol had symptoms. The incidence of headache (metrizamide, 34%; iohexol, 26%) was not statistically different, but the quality of the headache differed: half of the metrizamide headaches were moderate or severe, whereas all iohexol headaches were mild. Nausea (31%) and vomiting (28%) were common with metrizamide but unusual (3% nausea) with iohexol. Of the metrizamide patients, 21% had overt psychologic changes that did not occur in the iohexol group.     

Iohexol versus metrizamide for cervical myelography: double-blind trial

Cervical myelography was performed by lateral C1-C2 puncture in 60 patients. Thirty patients received iohexol (an investigational aqueous contrast agent) and 30 received metrizamide in order to provide a prospective, randomized, double-blind trial comparing these contrast media. The two media produced radiographs of equal quality. Contrast-related morbidity was suffered by four patients (13%) in the iohexol group and by 11 patients (37%) in the metrizamide group. These features indicate that iohexol is superior to metrizamide as a contrast agent for cervical myelography.     

Iotrol versus metrizamide in lumbar myelography: a double-blind study

In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population.     

The effect of intrathecal iohexol on visual evoked response latency: a comparison including incidence of headache with iopamidol and metrizamide in myeloradiculography

Fifty consecutive unselected patients referred for myeloradiculography and examined by the same radiologist, when facilities for measuring the visual evoked response were available, are considered. The effect on the visual evoked response of the examination and the incidence of headache following the use of iohexol as the contrast medium are compared with those after the use of iopamidol and metrizamide reported in a previous study. A total of 400 cases examined with iopamidol and 200 cases examined with iohexol are reviewed with regard to the incidence of headache. Whereas iopamidol and, to a greater extent metrizamide, were found to cause significant lengthening of the visual evoked response latency 20 hours after the radiological examination, iohexol did not. Furthermore there was no significant difference in the 20 hour reading following the use of iohexol compared with the original control group of patients who underwent lumbar puncture alone. There was a lower incidence and severity of headache following the use of iohexol than with iopamidol and a markedly reduced incidence compared with metrizamide. Iohexol is considered less neurotoxic than iopamidol which had previously superceded metrizamide as the contrast medium used for myeloradiculography in the Royal Surrey County Hospital. Volumes of up to 14 ml of iohexol 300 mg I/ml have been used for lumbar radiculography and for total myelography and up to 10 ml for direct lateral cervical puncture. In 350 cases examined to date with iohexol the only serious sequel was a case of chemical meningitis following the lumbar injection of 10 ml of the 300 mg I/ml solution for a cervical examination. The patient made an uneventful recovery.     

Myelography with iohexol (Omnipaque): review of 300 cases

The side effects of iohexol were evaluated in the 300 patients who had nonemergency myelography over a 9 month period. No patients studied with myelography were excluded from the iohexol trial. Age range was 14-86 years. Introduction was by lumbar puncture in 206 patients and by lateral C1-C2 injection in 94. Side effects, including discomfort, were denied by 81.3% of the patients. The other 18.7% had adverse reactions, the most common being headache, reported by 11% of the total population studied. Image quality was judged unsatisfactory in 8.1% of cervical myelograms and in 2.6% of lumbar myelograms. With lumbar injection, cervical myelograms were judged to be inadequate in 13.5%; with cervical injection, lumbar myelograms were inadequate in 25%. Iohexol caused significantly fewer side effects in the 300 patients than would have been expected with metrizamide. The low cost and ease of use are additional factors that favor iohexol as the contrast agent of choice for myelography.     

Lumbar myelography with iohexol and metrizamide. A double-blind clinical trial

Two non-ionic contrast media, iohexol and metrizamide, were compared in a double-blind clinical trial which included 50 patients who underwent lumbar myelography for disc herniation or spinal stenosis. The frequency of adverse reactions was lower for iohexol which is recommended for extended trials and for examination of other compartments of the subarachnoid space.     

Psychic changes following myelography with metrizamide and iohexol. A comparative investigation with psychologic tests

Based upon the results of repeated psychologic tests, psychic impairment following myelography has been studied in 60 patients. Thirty of these had lumbar myelography with metrizamide and 30 with iohexol. Psychic impairment was noted in both groups, although with a higher frequency and much more marked in the group which had metrizamide myelography. For this type of examination iohexol is thus to be recommended.     

Cognitive and affective changes after myelography: a comparison of metrizamide and iohexol

A battery of brief cognitive tests and a mood scale were administered to 42 patients before and after cervical myelography with either metrizamide (20 patients) or iohexol (22 patients). The patients receiving metrizamide experienced a deterioration in mood after myelography and a relatively greater decline in cognitive test performance than did those receiving iohexol. These two side effects tended to occur together in the metrizamide group, suggesting a common underlying cause; but there was no correlation between changes in mood and cognitive function after myelography with iohexol. These results suggest that metrizamide has a greater neurotoxic effect than iohexol.     

Clinical experience with iopamidol for myelography

Within 20 months 145 ascending thoracocervical myelographies and 155 lumbar myelographies with the nonionic water-soluble contrast medium iopamidol were performed. The iodine concentration given was 250 mg I/ml or 200 mg I/ml respectively. The total iodine never exceeded 2.5 g (8-10 ml). Image quality was assessed in terms of diagnostic value having experience of more than 1,000 myelographies using metrizamide. Picture quality was similar to metrizamide of equal iodine concentration. In 35 patients electroencephalography (EEG) was recorded before and after myelography with iopamidol 250. No changes that could be referred to the contrast medium were seen. There were no adverse reactions to lumbar myelography other than those following the lumbar puncture. In thoracocervical myelography mild and transient side effects occurred in 41 (28.3%). The most common were headache (41 cases), nausea (12), radicular pain (10), and dizziness (five). General seizures and psychopathologic symptoms were not observed.     

Iohexol and metrizamide in lumbar myelography. Comparison of side effects

In routine lumbar myelography carried out in 100 patients iohexol (n = 50) produced side effects in fewer patients (p less than 0.03), especially meningeal and cerebral (p less than 0.03), and among these a lower rate of headache (p less than 0.07), than did metrizamide. The overall frequency of afflicted patients (50% after iohexol and 72% after metrizamide) was high, mainly because of deliberate inclusion of patients with a high risk of side effects in the investigation. The side effects recorded up to six hours after the administration of the contrast medium were less frequent when using iohexol. If severe side effects are present at 24 hours or appear thereafter, as occurred in a few of the present patients after iohexol, surgical treatment or discharge of the patient is in some cases unnecessarily delayed.     

Risk of seizures after myelography: comparison of iohexol and metrizamide

A parallel, double-blind, randomized study comparing iohexol and metrizamide--both 180 mg l/ml--in lumbar myelography was carried out in 60 consecutive patients. Eight to 15 ml of contrast medium were administered with the upper level at the middle thoracic column. A detailed neurologic examination was performed before and 24 hr after myelography. EEG recordings--evaluated visually and with fast Fourier transformation analysis--and somatosensory evoked responses were registered before, 6 hr after, and 24 hr after myelography. All patients were observed for adverse reactions for 24-48 hr. Iohexol did not produce any epileptiform activity but epileptiform activity was detected in five patients receiving metrizamide. Iohexol produced significantly less frequent and less severe EEG changes than did metrizamide both at visual evaluation (p less than .0025) and at fast Fourier transformation analysis (p less than .04). No significant changes occurred in the early components of the somatosensory evoked potentials after either contrast medium. Iohexol caused significantly (p less than .002) less frequent and less severe adverse reactions than did metrizamide. The neurologic examination revealed no changes of clinical importance with either contrast agent.     

Ambulatory myelography using iohexol (Omnipaque): methods and results

Outpatient myelography with iohexol (Omnipaque) was performed in 150 patients. Side effects were noted in 28 patients (19%), with only 3 (2%) major complaints. It concerned 2 patients with severe and prolonged headache and one patient with seizures. Side effects were not more frequent in outpatient myelography than in reported series of hospitalized patients. The frequency of side effects was significantly lower with the use of iohexol than in comparable studies with metrizamide. Headache was the most frequent side effect, followed by an increase or exacerbation of ischiatiform pain, nausea and vomiting. Side effects were slightly more frequent in cervical myelography than in lumbar myelography and were not related to underlying pathology. It is concluded that outpatient myelography is feasable for as far as iohexol is used and patient surveillance is carefully organized.