Biomedical subjects

D K Kido

Publications and source records attributed to D K Kido.

At least 37 records · Page 2Linked to original sources

PubMed1989

Gadolinium-DTPA-enhanced magnetic resonance scanning in cerebellopontine angle tumors.

Magnetic resonance (MR) imaging has quickly emerged and already replaced computerized tomography (CT) in the evaluation of cerebellopontine angle (CPA) lesions, although even MR scanning may occasionally yield equivocal results. We recently studied six patients with a new MR image-enhancing contrast, gadolinium-DTPA (Gd-DTPA). All patients were suspected of having CPA pathology, and the standard MR scan was either negative, equivocal, or left unanswered questions regarding confirmed lesions. The Gd-DTPA-enhanced MR scan confirmed tumors or added useful information in five of six patients.

Adult↗

PubMed1988

The role of C.T. scans in managing the orbital complications of ethmoiditis.

Thirty-three cases of ethmoidities with orbital complications were reviewed to determine the accuracy of clinical diagnosis and the benefit of CT scans in planning treatment. Patients were classified according to the Schramm et al. 1982 criteria of orbital involvement with ethmoiditis: periorbital cellulitis with chemosis (PCC)-9, and orbital cellulitis (OC)-11, subperiosteal abscess (SPA)-9, and orbital abscess (OA)-4. These patients received CT scans acutely for diagnostic purposes and demonstrated an 84% accuracy with the final clinical groupings. Of 33 patients, 9 had a shift in clinical classification based on the CT scan result interpreted by the Radiology Department or surgical findings. There were no false positives in the periorbital or orbital cellulitis patients, and no false negatives in the subperiosteal and orbital abscess patients. Thus classification changes caused no change from medical to surgical treatment in any of the cases. The conclusion is that a knowledgeable clinical exam established the correct grouping in 70% of the patients versus 82% with the CT scan. An urgent CT scan is advised for patients in clinical groups SPA, OA, or cavernous sinus thrombosis (CST) to determine the imminent need for surgery, as the cases may be underestimated. Patients with PC or PCC can be managed medically with elective CT scans not routinely indicated.

Abscess↗

PubMed1988

The role of catheters and guidewires in the production of angiographic thromboembolic complications.

Thromboembolic complications occurring during angiography may result from a number of different causes. Catheters and guidewires can interact with blood to form thrombi; this tendency is related to wall defects and the chemical composition and structural characteristics of the catheters and guidewires. Nonthrombic sources of emboli may consist of foreign bodies derived from surgical equipment or may exist in the flushing solution and contrast media. Plastic emboli may be shed from catheters and guidewires when the guidewires are passed through the catheters. Air emboli may result from poor technique or loose fitting connections between the catheter and injector or syringe; they can mimic emboli from catheters and guidewires. A number of strategies for decreasing the risk of thromboembolic complications during angiography are reviewed.

Angiography↗

PubMed1988

Moyamoya disease in an infant with autonomic dysfunction: angiographic and MRI findings.

An infant with persistent Harlequinism went on to develop a hemiparesis secondary to Moyamoya disease at 2 1/2 months of age. The sympathetic nervous system is proposed to be an etiologic factor in the pathophysiology of Moyamoya disease as well as Harlequinism. This is one of the youngest patients reported in the English literature with Moyamoya disease and the only report of the coexistence of Moyamoya disease and atypical Harlequinism. Magnetic resonance imaging led to the diagnosis, which was confirmed by cerebral angiography.

Arterial Occlusive Diseases↗

PubMed1988

New imaging techniques in diagnosis of cerebrospinal fluid fistula.

The localization of a cerebrospinal fluid fistula producing cerebrospinal fluid otorrhea can be very difficult. However, the exact anatomic localization of the bony defect is important when selecting the surgical approach to repair. Case reports of two patients in whom spontaneous cerebrospinal fluid otorrhea occurred following pressure equalization tube placement for middle-ear effusion are presented. Nuclear magnetic imaging supplemented CT scan findings, providing noninvasive localization of the defect. Preoperative impressions were confirmed at surgery. In addition to discussing the use of magnetic resonance imaging in evaluating cerebrospinal fluid otorrhea, the literature will also be reviewed.

Brain Diseases↗

PubMed1987

Effect of multiple intravenous injections of diatrizoate on iodine concentrations and osmolality. An experimental study in rabbits.

Multiple intravenous injections of contrast media are used in radiology, but information regarding corresponding changes in the serum iodine concentrations and osmolality is lacking. We measured the changes in serum iodine concentration and serum osmolality in rabbits after a series of intravenous injections of contrast media. Hypaque-76 (1 cc/kg) was injected intravenously in awake rabbits at 10-minute intervals for 1 hour and arterial blood sampled at midpoint times between injections. During the 1-hour period of seven serial injections, mean serum iodine concentration at 5 minutes was 2.3 mg I/cc (+/- 0.1 SEM, n = 14); at 35 minutes, 5.1 mg I/cc (+/- 0.2); and at 65 minutes, 6.7 mg I/cc (+/- 0.4). The mean peak concentration was 6.8 mg I/cc (+/- 0.4). Serum osmolality underwent a mean increase of 16 mosm/kg during the injection period. Hypertonic mannitol injections produced a smaller increase in osmolality (10 mosm/kg). Isotonic saline injections in control animals produced no change in osmolality.

Animals↗

PubMed1987

Physiologic effects of contrast media in the rabbit.

The intravenous administration of contrast media (CM) is often associated with alterations in blood pressure (BP) and heart rate (HR). Osmolality is thought to play a role, but the magnitude and even the direction of change may vary under similar osmotic conditions indicating the involvement of other mechanisms. Conscious rabbits received sodium-meglumine diatrizoate (76%, 1 mL/kg, ear vein) every 10 minutes for 1 hour. A similar injection protocol was performed with normal saline and mannitol (36%), equiosmotic to the contrast agent. BP and HR were monitored continuously. Blood samples were collected at the midpoint between each injection for determination of hematocrit, serum osmolality, and iodine concentration. Group parameters at each time point were compared with the Student's t-test. The administration of mannitol caused changes in serum osmolality, hematocrit, and HR as great or greater than the changes caused by equiosmotic diatrizoate. However, BP increased significantly in the diatrizoate group but not in the mannitol group, relative to normal saline. These results suggest that osmolality is important for certain physiologic changes induced by CM, but that BP changes involve mechanisms in addition to osmolality.

Animals↗

PubMed1987

Opiate involvement in contrast media-induced blood pressure changes.

The intravenous administration of contrast media (CM) often alters blood pressure (BP). Osmolality plays a role, but the magnitude and even direction of change varies under similar (osmotic) conditions, indicating the involvement of other mechanisms. Male Wistar rats, anesthetized with pentobarbital, received sodium/meglumine diatrizoate, iohexol, or normal saline, 4 ml/kg, via a tail vein, while blood pressure was recorded continuously. Additional groups were pretreated with the opiate antagonist, naloxone (1 mg/kg, IV), or with an equal volume of normal saline 5 minutes prior to the diatrizoate injection. Comparisons of BP change were made with the Student's t-test. Diatrizoate caused a significant (P less than .0002) increase in BP relative to the saline control group, iohexol did not. Thus, the increase with diatrizoate was significantly greater than with iohexol (P less than .00006). Neither the saline nor naloxone pretreatment altered BP significantly. Saline pretreatment did not alter the significant increase in BP produced by the diatrizoate. However, the diatrizoate-induced increase in BP was prevented by the naloxone pretreatment and was significantly less than after the saline pretreatment (P less than .0001). Based on these and previous results, the authors hypothesize that release of endogenous opioids may play a role in BP changes caused by intravenous CM and that significant CM-induced changes may be prevented pharmacologically with the selective opiate blocker, naloxone.

Animals↗

PubMed1987

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.

Adult↗

PubMed1987

Physiologic changes during high field strength MR imaging.

High field strength MR imaging systems may require several kilowatts of RF power to obtain images. A fraction of this power is absorbed by the patient, and changes in body temperature have been measured in experimental animals. The purpose of this study was to quantify changes in body surface temperature and other physiologic parameters in humans during MR scanning at 1.5 T. Blood pressure, heart rate, respiration, and axillary temperature measurements were obtained on 27 normal volunteers. Measurements were made at RF power levels of 0, 0.2, and 0.8 W/kg, with the power sequence randomized. In 14 volunteers receiving lumbar scans, statistically significant increases in temperature were observed at RF power levels of 0.2 (+0.2 +/- 0.1 degree C) and 0.8 (+0.5 +/- 0.1 degree C) W/kg. No significant changes related to RF power were observed in blood pressure or respiratory rate. At the 0.8 W/kg level there was a slight increase in heart rate (3 +/- 1.3 beats per minute). In the 13 patients receiving head scans, physiologic changes were substantially smaller. The temperature increases and other physiologic changes observed during MR scanning with the 1.5 T imager at RF powers of 0.2 and 0.8 W/kg were small and of no clinical concern. Additional studies should be performed in patients with cardiac failure, vascular occulusion, and metallic implants or prostheses.

Adult↗

PubMed1986

Postoperative radiographic appearance of intracranial hemostatic gelatin sponge.

Hemostatic gelatin sponges were placed in hemispheric defects created in four dogs which were then periodically scanned by computed tomography to determine the postoperative appearance of the sponges. The hemostatic sponges appeared as low attenuation regions for 7-10 days. The attenuation value of these Gelfoam cavities was intermediate between fat and air. Subsequently, clinical cases were selected in which the location of gelatin sponges were known to demonstrate the appearance of the material in patients. In addition to enhancing the accuracy of computed tomographic interpretation, we have found that the gelatin sponge can be useful as a transient computed tomography marker for localization of surgical activity.

Adolescent↗

PubMed1986

Corpus callosum and subcallosal-periventricular lesions in multiple sclerosis: detection with MR.

Examination with magnetic resonance imaging of 40 patients with confirmed diagnoses of multiple sclerosis showed that corpus callosum involvement is common. Thirty percent of the patients had focal callosal lesions similar to those described in the pathology literature. Long, inner callosal-subcallosal lesions were found in 55% of patients. These lesions had signal characteristics similar to those of noncallosal periventricular lesions. Diffuse moderate to severe atrophy of the corpus callosum was noted in 40% of patients, with one exception concurrent with inner callosal lesions. The nature of the inner callosal lesions is not known, since these lesions are not typically described in the literature. These lesions may represent demyelination or increased water content and may be the precursor to atrophy that progresses from the ependymal surface toward the outer fibers of the corpus callosum.

Adult↗

PubMed1986

Neurologic complications in diabetics after metrizamide lumbar myelography.

Recognized risk factors for metrizamide myelography are seizure disorder, seizure-threshold-lowering drugs, dehydration, and possibly age. After observing serious neurologic complications in diabetic patients after routine metrizamide myelography, a retrospective study was conducted to determine if diabetes should be considered another independent and important risk factor. Forty-one diabetic patients who had lumbar metrizamide myelograms were compared with a control group of 110 nondiabetic patients. A significantly higher incidence was found of severe vomiting (15% vs. 3%, p less than 0.01) and neurologic complications (20% vs. 2%, p less than 0.001) in the diabetic population. Neurologic complications included one case each of seizure, severe encephalopathy, auditory and visual hallucinations, and prolonged somnolence and four cases of confusion-anxiety. Four of the diabetic patients had major transient elevations of blood pressure. These findings suggest that diabetics are a high-risk population for metrizamide myelography. The dose of metrizamide should be minimized, whenever possible. The new nonionic myelographic agents may prove to be safer in this population, but caution and careful follow-up should be exercised in the initial trials with these patients.

Aged↗

PubMed1986

A methodologic assessment of studies comparing magnetic resonance imaging and computed tomography of the brain.

To evaluate the methods used in studies comparing magnetic resonance imaging (MRI) and computed tomography (CT) of the brain, we reviewed English language articles published between 1981 and early 1986. Of 83 studies comparing the accuracy of MRI and CT in 10 or more patients, few met methodologic standards for evaluations of the efficacy of new diagnostic tests. Limitations were found in how study populations were assembled, in test performance and interpretation, and in analysis of study findings. Greater attention to design and execution of comparison studies could overcome these limitations and help demonstrate MRI's true diagnostic value.

Brain↗

PubMed1985

Pharmacokinetics and excretion of iohexol after lumbar myelography in man.

Pharmacokinetics and excretion of iohexol, a new nonionic water-soluble contrast medium, were determined after lumbar myelography. Peak plasma concentrations were obtained 2 to 6 hours after injection and ranged from 29 to 177 microgram/ml. Terminal elimination half-life was 4.0 hours, and over 90% of the dose was recovered in the urine within 24 hours. In one patient with a large lumbar cauda equina tumor, absorption and excretion were delayed; but eventually 99% was recovered indicating a large capacity for reabsorption via the lumbar subarachnoid space. One mild headache of 5 minutes' duration was reported in a 73-year-old woman. No significant changes in vital signs, neurologic examinations, or serum chemistries were observed.

Adult↗

PubMed1984

Lumbar myelography with iohexol and metrizamide: a comparative multicenter prospective study.

Diagnostic quality of radiographs and adverse reactions associated with the use of metrizamide and iohexol as contrast agents in lumbar myelography were compared in a prospective randomized double blind study in 350 patients at seven centers. The contrast media were administered in comparable volumes at a concentration of 180 mg I per ml. Overall quality of radiographic visualization was graded good or excellent in 95% of 175 metrizamide studies and in 98% of 175 iohexol studies. Ninety-three patients examined using metrizamide (53%) and 130 patients examined using iohexol (74%) experienced no discomfort during or after myelography. Postmyelographic headache was associated with 38% of metrizamide examinations and 21% of iohexol examinations. Nausea and vomiting were also more common with metrizamide. Five patients examined using metrizamide (3%) experienced transient confusion and disorientation following lumbar myelography. No such reactions were observed following iohexol myelography.

Adolescent↗

PubMed1984

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.

Adolescent↗

PubMed1984

Lumbar myelography with metrizamide in rabbits. An investigation of contrast media penetration and resorption.

Neurotoxicity from subarachnoid contrast media is probably related to their specific pharmacologic effects and to their penetration into the central nervous system. The lack of a barrier between the cerebrospinal fluid and the extracellular fluid of the brain and cord allows water-soluble contrast media to diffuse into the neural tissue. The aim of this investigation was to develop a method that allows one to quantify the neural tissue penetration for a given contrast medium in relation to the cerebrospinal fluid concentration and contact time and apply this to the use of metrizamide. The result shows a good correlation between iodine concentration in the lumbar cerebrospinal fluid and that in the lumbar cord suggestive of a simple diffusion. When time of sacrifice (contact time) is added as a covariant there is also some indication of retention of metrizamide in the neural tissue. The investigation also demonstrates that the resorption of the contrast medium in the rabbit in this experimental model is mainly in the lumbo-sacral region.

Animals↗