Bone marrow fat and bone mineral density on proton MR spectroscopy and dual-energy X-ray absorptiometry: their ratio as a new indicator of bone weakening.

Objective: Bone weakening can be affected by agents other than bone mineral density (BMD). Increased bone marrow fat may have a direct link to bone loss. This pilot study analyzes the relationship between bone marrow fat and BMD in subjects with normal and structurally weakened vertebrae.

The value of magnetic resonance imaging of the lumbar spine to predict low-back pain in asymptomatic subjects : a seven-year follow-up study.

Background: In 1989, a group of sixty-seven asymptomatic individuals with no history of back pain underwent magnetic resonance imaging of the lumbar spine. Twenty-one subjects (31%) had an identifiable abnormality of a disc or of the spinal canal. In the current study, we investigated whether the findings on the scans of the lumbar spine that had been made in 1989 predicted the development of low-back pain in these asymptomatic subjects.

Potential value of vertebral proton MR spectroscopy in determining bone weakness.

Background And Purpose: Increased fat content in vertebrae may indicate bone weakness. Vertebral proton MR spectroscopy ((1)H MRS) quantitatively measures vertebral fat relative to water. Thus, (1)H MRS measurements of percent fat fraction (%FF) and spectral line width (LW) of vertebral bone marrow may differ between subjects with and those without MR imaging evidence of weakened bone.

The fetus at term: in utero volume-selected proton MR spectroscopy with a breath-hold technique--a feasibility study.

In three healthy gravidas at 38 and 39 weeks gestation, fetal MR spectroscopy was performed with a breath-hold technique by using the following pulse sequences: single voxel point-resolved spectroscopy, or PRESS, for liver and heart studies and stimulated-echo acquisition mode, or STEAM, for brain studies. Signal peaks of lipid from heart and liver were detected, as were the signal peaks of choline, creatine, and N-acetylaspartate from fetal brain. Findings demonstrated the feasibility of performing proton MR spectroscopy to assess mobile fetal structures.

Normal lumbar vertebrae: anatomic, age, and sex variance in subjects at proton MR spectroscopy--initial experience.

Fifty-seven subjects underwent proton magnetic resonance (MR) spectroscopy of the second lumbar vertebra to evaluate single-voxel and multivoxel techniques. Measurements included lipid-to-water ratios, lipid fractions, and line width. These data provide information about vertebral fat content.

A vascular sarcoid mass mimicking a convexity meningioma.

We report a 48-year-old woman with a left posterior temporal extra-axial mass that had the imaging characteristics of a meningioma on preoperative CT, MRI and angiography. However, a biopsy diagnosis of sarcoidosis was made. This case illustrates that dural-based sarcoid masses can be very vascular and radiographically indistinguishable from meningiomas.

2D CSI proton MR spectroscopy of human spinal vertebra: feasibility studies.

This report focuses on proton magnetic resonance spectroscopy (1H MRS) of spine vertebra acquired with two-dimensional chemical shift imaging (2D CSI), utilizing the stimulated echo acquisition mode (STEAM) sequence. Both validity and reproducibility studies were performed. To validate the 2D CSI method, its spectra were compared with those obtained with the single-voxel (SV) method.

Taste memory induces brain activation as revealed by functional MRI.

Purpose: Our goal was to use functional MRI (fMRI) to measure brain activation in response to imagination of tastes in humans.

Method: fMR brain scans were obtained in 31 subjects (12 men, 19 women) using multislice FLASH MRI and echo planar imaging (EPI) in response to imagination of tastes of salt and sweet in coronal sections selected from anterior to posterior temporal brain regions. Activation images were derived using correlation analysis, and ratios of areas of brain activated to total brain areas were calculated.

Odor memory induces brain activation as measured by functional MRI.

Purpose: Our goal was to use functional MRI (fMRI) to measure brain activation in response to imagination of odors in humans.

Method: fMR brain scans were obtained in 21 normal subjects (9 men, 12 women) using multislice FLASH MRI in response to imagination of odors of banana and peppermint and to the actual smells of the corresponding odors of amyl acetate and menthone, respectively, in three coronal sections selected from anterior to posterior temporal brain regions. Similar studies were obtained in two patients with hyposmia using FLASH MRI and in one patient with hyposmia using echo planar imaging, both before and after theophylline treatment, which returned smell function to or toward normal in each patient.

Increased brain activation in response to odors in patients with hyposmia after theophylline treatment demonstrated by fMRI.

Purpose: Our goal was to demonstrate that medical therapy in patients with smell loss (hyposmia) that restored olfactory function toward or to normal could be verified and quantitated by functional MRI (fMRI) of brain and that visual representation of these changes could be used to identify these patients.

Method: Multislice FLASH MR or echo planar MR brain scans were obtained in four patients with hyposmia in response to three olfactory stimuli both before and after treatment with theophylline. Activation images were derived using correlation analysis, and ratios of brain area activated to total brain area were obtained.

Mapping brain activation to odorants in patients with smell loss by functional MRI.

Purpose: Our goal was to use functional MRI (fMRI) to develop an objective, noninvasive technique by which patients with smell loss can be identified, their abnormalities quantitated, their results compared with findings in normal subjects, and visual representation of their CNS pathology obtained.

Method: Functional MR brain scans were obtained in eight patients with hyposmia in response to three olfactory stimuli (pyridine, menthone, amyl acetate) in three coronal brain sections selected from anterior to posterior temporal brain regions using multislice FLASH MRI. Results were compared with similar studies performed in 17 normal subjects.

Functional MRI of human olfaction.

Purpose: Our goal was to use functional MRI (fMRI) to measure brain activation in response to olfactory stimuli.

Method: fMRI brain scans were obtained in 17 normal subjects (9 men, 8 women) using-multislice FLASH MRI in response to three olfactory stimuli (pyridine, menthone, amyl acetate) in three coronal brain sections selected from anterior to posterior temporal brain regions. Activation images were derived using correlation analysis, and ratios of areas of brain activated to total brain areas were calculated.

Patterns of anterior spinal canal involvement by neoplasms and infections.

Purpose: To show that retrovertebral extension of neoplastic and infectious disease proceeds in a predictable manner, with the anatomic superstructure determining the shape of the advancing process.

Methods: We examined 58 patients who had neoplastic (n = 44) and infectious (n = 14) processes that caused canal compromise. In total, 140 levels were examined by means of MR imaging only (48 patients), CT only (1 patient), CT plus MR imaging (3 patients), and MR imaging plus CT myelography (6 patients).

Orientation of the lumbar facet joints: association with degenerative disc disease.

The orientation of the lumbar facet joints was studied with magnetic resonance imaging in 140 subjects to determine if there is an association between facet tropism and intervertebral disc disease or between the orientation of the facet joints and degenerative spondylolisthesis. The 140 subjects were divided into four groups: sixty-seven asymptomatic volunteers, forty-six of whom did not have a herniated disc on magnetic resonance scans (Group I) and twenty-one who did (Group II); forty-six symptomatic patients who had a herniated disc confirmed operatively (Group III); and twenty-seven patients who had degenerative spondylolisthesis at the interspace between the fourth and fifth lumbar vertebrae (Group IV). Axial scans were made at each lumbar level and digitized, and the facet joint angle was measured by two independent observers with use of image analysis software in a personal computer.

Flow-sensitive magnetic resonance imaging in the evaluation of cerebrospinal fluid leaks.

Cerebrospinal fluid (CSF) leaks involving the skull base are associated with considerable morbidity and mortality, and often present a diagnostic challenge. Current diagnostic methods are invasive and cumbersome and involve substantial radiation exposure of the patient. The authors identified seven patients with clinically suspected CSF leaks and evaluated them with a flow-sensitive magnetic resonance imaging (MRI) sequence in addition to more conventional studies.

Atypical cerebral aneurysm in a young child.

Autopsy findings are described of an atypical aneurysm of a large cerebral artery in a young child. The lesion is believed to have been an infective (mycotic) aneurysm. Antibiotics were administered at the time of the first leakage which had been thought to be due to a sinus infection.

A clinical and neuropathologic study of silk suture as an embolic agent for brain arteriovenous malformations.

Purpose: To evaluate the safety and efficacy of silk suture as an agent for preoperative embolization of cerebral arteriovenous malformations.

Methods: Clinical and histopathologic results were analyzed in six patients who underwent embolization of cerebral arteriovenous malformations using silk suture in combination with other agents.

Results: Three of the patients treated with silk hemorrhaged after embolization, and two of these patients died.

Sacral meningeal cysts: evaluation with MR imaging.

It is often difficult for the radiologist to determine if a given sacral meningeal cyst is causing symptoms. Radiographic criteria for identifying cysts likely to be symptomatic are needed. Using conventional magnetic resonance (MR) imaging along with a specifically designed flow-sensitive sequence, the authors characterized 24 cysts (19 patients) with respect to diameter and communication with the subarachnoid space.

Isolation of the fourth ventricle causing transtentorial herniation: neurosonographic findings in premature infants.

Objective: Significant posthemorrhagic enlargement of the fourth ventricle occurs only in a small minority of patients. Although entrapment or isolation of any ventricle can occur, the fourth ventricle is the most common site. This study was undertaken to better understand enlargement of the fourth ventricle after intraventricular hemorrhage and the neurosonographic features of isolation and transtentorial herniation.

MR of slow CSF flow in the spine.

Purpose: To evaluate a slow-flow MR sequence in normal CSF flow and in CSF flow disturbance in cases of spinal stenosis.

Method: The method was tested for flow sensitivity and applied to 67 sites of spinal canal compromise.

Results: Phantom studies show that flow can be depicted at a velocity of 0.

PACS clinical experience at Georgetown University.

Georgetown University Hospital has been operating an image management and communications system (IMACS or PACS) for 3.5 years. This work was initially funded under the Army Medical Research and Development Command Digital Imaging Network Systems (DINS) project.

Regression of pituitary macroadenoma after pituitary apoplexy: CT and MR studies.

We present a case of a patient with apoplexy due to infarction of a large pituitary macroadenoma. Conservative treatment with steroids resulted in reversal of symptoms and the adenoma involuted. This suggests that medical management may be sufficient therapy in some patients with this complication.

PACS clinical experience at Georgetown University.

Georgetown University Hospital has been operating an image management and communications system (IMACS or PACS) for three-and-a-half years. This work was initially funded under the Army Medical Research and Development Command Digital Imaging Network Systems (DINS) project. The system was taken from a research system supporting only radiology tasks to one extended to clinical use, and has been used in clinical work for two-and-a-half years.