Hemangioma of the temporal bone in a patient presumed to have Ménière's syndrome.

This case report describes a patient with a facial nerve hemangioma of 8 years' duration that initially caused most of the symptoms of Ménière's syndrome: fullness, sensorineural hearing loss, dizziness, tinnitus, and disruption of balance. The hearing loss was in the high-frequency range (> or = 3,000 Hz); typically, the initial hearing loss in Ménière's syndrome is in the low-frequency range. Mild facial nerve weakness and punctate keratitis due to corneal exposure appeared 8 years later. Contrast-enhanced magnetic resonance imaging and high-resolution computed tomography depicted the lesion and made preoperative diagnosis possible. With meticulous surgical removal of the tumor, which was intertwined with the facial nerve, facial nerve function was preserved.

Unusual subclavian steal: bidirectional and antegrade blood flow in the vertebral artery.

We present an unusual radiographic manifestation of subclavian steal seen in six patients. These cases differ from the classic form of subclavian steal in that antegrade and bidirectional blood flow in the vertebral-subclavian artery system is seen, resulting in the steal phenomenon.

Computer-based radiology information system: from floppy disk to CD-ROM.

The authors have developed a comprehensive computer-based radiology information system known as "Radiology Resource and Review" (R3). The content is divided into 10 radiology information categories spanning the entire human body and presently includes more than 4 Mbytes of text, 9,000 topics, and 6,000 images. The R3 software and the information content are stored on compact disk, read-only memory (CD-ROM) media. The images are compressed by using a standard compression algorithm. Images and text are cross-indexed with more than 13,000 key words, which can be linked together in searches by using Boolean logic. Four different retrieval interfaces support browsing of text and image information, diagnosis decision making, self-study, and teaching file preparation. The 10-year university-funded evolution of R3 is an example of the transition in storage media from floppy disk to CD-ROM.

Computerized case-based instructional system for computed tomography and magnetic resonance imaging of brain tumors.

RATIONALE AND OBJECTIVES: A computerized system that applies the case-based approach to training radiologists to diagnose brain tumors was designed. The authors attempted to provide residents a tool that supports their visual memory and inducts case-based reasoning. METHODS: A relational database with a digital image library was implemented and incorporated into a computer aided instruction environment based on case presentation. An indexing system was structured around case features (case history and radiologic findings). "If-then" type rules were used to control the search direction within the case library and to generate lists of diagnostic hypotheses. The indexing system was evaluated against cases "known" to the system. RESULTS: The current case library consists of 122 cases with 640 digitized images (computed tomography and magnetic resonance imaging). The accuracy of retrieval for "known" to the system cases was 80.7%. CONCLUSIONS: A case library stored on a personal computer can be efficiently searched for a combination of radiologic findings and can offer quality images for comparison to the case in question. A case library is a source of the information that may be used by different teaching applications.

Parathyroid scintigraphy with iodine-123 and 99mTc-sestamibi: imaging findings.

Subtraction scintigraphy with 99mTc-pertechnetate and 201Tl-chloride is widely used for localizing the parathyroid gland, but the sensitivity of this method averages only 55%. The sensitivity of scintigraphy is improved by using a combination of 99mTc-sestamibi and iodine-123. Parathyroid adenomas can also be localized with 99mTc-sestamibi alone by subtracting early images from late sequential images. The fast washout of 99mTc-sestamibi from the thyroid gland allows visualization of the parathyroid gland. The purpose of this essay is to illustrate the findings of abnormalities of the parathyroid glands when using a combination of 99mTc-sestamibi and iodine-123.

MRI of iatrogenic spinal epidermoid tumor.

A child who had received multiple lumbar punctures 6 years previously was found to have an acquired epidermoid tumor of the lumbar spinal canal, a rare intraspinal lesion. The isointense epidermoid tumor showed ring enhancement only after gadolinium administration.

MR artifacts after anterior cervical diskectomy and fusion: a cadaver study.

OBJECTIVE: To identify the source of metallic artifacts observed on cervical spine MR studies following anterior cervical diskectomy and fusion (ACD&F), preoperative and postoperative MR studies were done on cadavers using standard spin echo T1, T2, and GRASS imaging. MATERIALS AND METHODS: An ACD&F was performed on each cadaver at various levels using different combinations of drill burrs, curettes, and suction tips. RESULTS: Results showed that contact between the drill burr and suction tip produced the worst artifacts; however, artifacts still occurred in cases in which the suction tip was not introduced. CONCLUSION: This observation suggests that metal flakes from the curettes also produced artifacts. Image distortion was greater on GRASS imaging than on the spin echo imaging.

Posttraumatic pseudoaneurysm of the posterior meningeal artery associated with intraventricular hemorrhage.

A 22-year-old man sustained a severe head injury and had a torn posterior meningeal artery that caused massive intraventricular hemorrhage. Traumatic pseudoaneurysm of the posterior meningeal artery should be considered in cases where intraventricular hemorrhage occurs in the presence of occipital bone fracture and contiguous epidural hematoma; vertebral angiography is of value in this regard.

Lumbar myelography with iohexol in outpatients: prospective multicenter evaluation of safety.

A multicenter open, noncomparative evaluation of the safety of iohexol was prospectively conducted in 81 adult outpatients undergoing screen-film lumbar myelography. Iohexol (180 milligrams of iodine per milliliter) was administered via a lumbar route at a dose of 8-17 mL. Computed tomography (CT) was performed after myelography. The safety of iohexol was assessed by monitoring adverse reactions and neurologic status and by measuring vital signs and serum laboratory values. The most frequent adverse reaction was headache (16 of 81 patients [19.7%]). Twelve patients complained of a headache on the day of the myelographic procedure, and four patients reported a headache 24 hours after the procedure. Nausea or vomiting occurred in four of 81 patients (4.9%) only on the day myelography was performed. No other neurologic abnormalities were found. Iohexol produced myelographic and CT studies of good to excellent quality in all patients. This study indicates that iohexol can be employed safely in lumbar myelography of adult outpatients.

MRI in the evaluation of spina bifida patients in the remote period after meningomyelocele repair.

MRI was performed on 22 patients ranging in age from 3 months to 16 years who had closure of their meningomyelocele shortly after birth. These patients had developed new clinical findings suggestive of spinal cord dysfunction. MRI showed low placement of the spinal cord in all 22. Six patients had lipomas, five had diastematomyelia and six had hydromyelia. Four patients had an obviously dysplastic terminal cord.

Multiple intraparenchymal brain plasmacytomas with spontaneous intratumoral hemorrhage.

The case of a patient with two intraparenchymal brain plasmacytomas without cranial or dural attachment and with intratumoral hemorrhage is presented. Computed tomographic (CT) findings are described. Autopsy revealed two discrete intraparenchymal plasmacytomas with intratumoral hemorrhage, one cerebral and one cerebellar. There have been few case reports of brain plasmacytoma without cranial or dural attachment, and this case of multiple such intracranial, intraparenchymal plasmacytomas with hemorrhage is certainly unique. Intratumoral hemorrhage with intracranial plasmacytoma is extraordinarily rare. The literature of intracranial involvement with myeloma and plasmacytoma and the CT appearance of intracranial plasmacytoma are surveyed.

Sphenoid mucocele causing hyperprolactinemia: radiologic/pathologic correlation.

A suprasellar lesion masquerading as a pituitary tumor causing hyperprolactinemia in a 62-year-old man was found to be a large sphenoid mucocele. After it was successfully resected via a transsphenoidal approach, the patient's condition improved and the prolactin level fell to almost normal.

High-resolution computed tomography in intracranial aneurysms.

High-resolution computed tomography in intracranial aneurysms is a highly valuable procedure. Its indications are as follows: to determine the presence of subarachnoid hemorrhage and to predict the location of aneurysms; to identify and characterize saccular and giant aneurysms; to assess the complications of aneurysm rupture; to evaluate operative maneuvers and postoperative complications. The technique of high resolution computed tomography consists of unenhanced and enhanced 10-mm-thick sections followed by 1.5mm thin sections through suspicious areas. A bolus of 100cc of 60% meglumine diatrizoate is given for the enhanced study. A repeat bolus of 60cc of contrast agent is administered prior to the thin sections. Direct coronal scanning and sagittal/coronal reformatting is frequently used. This review will detail the technique used in this procedure as well as present examples of the major indications listed above. This is the procedure of choice for patients suspected of having had a subarachnoid hemorrhage or harboring an intracranial aneurysm.

Intraventricular cavernous hemangioma: report of three cases and review of the literature.

The clinical and radiographic presentations of 3 patients with intraventricular cavernous hemangioma are described. The accumulated total of 19 cases from the literature are compared to determine whether there is a common clinical and radiographic presentation for this benign intraventricular lesion. The differential diagnosis of intraventricular cavernous hemangioma includes intraventricular meningioma, choroid plexus papilloma, arteriovenous malformation, low grade astrocytoma, and ependymoma.

Lumbar myelography with iohexol and metrizamide. A comparative multicenter prospective study.

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

Radiology of thoracic and lumbar fractures.

High-resolution computed tomography (CT) is superior to other imaging modalities in assessing the extent and degree of spinal fractures. The determination of bone fragments within the spinal canal and the detection of posterior neural arch damage are major advantages offered by computed tomography. The addition of intrathecal contrast allows proper assessment of the oftentimes confusing neurologic picture. Plain roentgenograms of the spine are only the initial diagnostic examinations of spinal fractures. Roentgenograms in conjunction with high-resolution CT, performed with or without intrathecal contrast, provide the best evaluation of thoracolumbar spinal fractures.

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.

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.

Computed tomographic discography in the evaluation of extreme lateral disc herniation.

Thin section, high resolution computed tomographic (CT) scans of the lumbar spine produce images that can show herniated intervertebral discs without intravenous or intrathecal contrast enhancement. With this technique, the diagnosis of posterolateral and midline herniation has been greatly facilitated. This communication reports the use of CT discography in the preoperative evaluation of two patients who were shown at discography and proven at operation to have extreme lateral disc herniations.