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Biomedical subjects

J G Jarvik

Publications and source records attributed to J G Jarvik.

34 records · Page 2Linked to original sources
PubMed1997

Rapid MR imaging versus plain radiography in patients with low back pain: initial results of a randomized study.

PURPOSE: To demonstrate the feasibility of a randomized trial to compare rapid magnetic resonance (MR) imaging with plain radiography as the initial imaging study in patients with low back pain, to test measures of the decision-making process and patient outcomes, and to offer a model for using randomized clinical trials to evaluate diagnostic tests. MATERIALS AND METHODS: The authors randomly selected 62 patients with low back pain to undergo either rapid MR imaging or plain radiography. The authors measured functional status, satisfaction, and general health status at baseline and at 3 months. The modified Roland scale was the primary outcome measure. In addition, the authors examined diagnostic and therapeutic decision making and resources used by each group. RESULTS: There were no statistically significant differences between the two patient groups with respect to outcome (Roland score: MR imaging = 12.5, radiography = 12.1). MR imaging provided more useful information to clinicians and resulted in greater patient reassurance. CONCLUSION: Randomly selecting patients to undergo imaging examinations and measuring outcomes is feasible; however, a larger, multicenter study is necessary to determine whether rapid MR imaging is a cost-effective replacement for plain radiography in patients with low back pain.

Adult↗
PubMed1996

Proton spectroscopy in asymptomatic HIV-infected adults: initial results in a prospective cohort study.

The purpose of our study was to determine whether proton magnetic resonance spectroscopy (MRS) could detect early brain involvement by human immunodeficiency virus (HIV). We recruited 19 asymptomatic HIV-infected patients, 9 with and 10 without a history of intravenous drug use (IDU), as well as 10 control subjects. All subjects had to have normal MR imaging to be enrolled. We identified the following peaks on proton MRS: n-acetyl aspartate, creatine, choline, and a conglomerate amino acid peak between 2.1 and 2.6 parts per million that we call the marker peaks. Proton MRS was able to demonstrate a statistically significant difference between HIV-infected subjects and controls. The marker/Cr was the best ratio to separate patients from controls, with controls having a mean ratio of 0.50 +/- 0.51 and patients having a mean ratio of 1.8 +/- 0.85 (p = 0.001). There was no difference between HIV-infected subjects with and without a history of IDU. No significant relationship was found between either neuropsychological test scores or CD4 count and metabolite ratios. In brief, MRS seems more sensitive than magnetic resonance imaging (MRI), being able to detect abnormalities in HIV-infected patients when imaging is normal.

Adult↗
PubMed1996

Interreader reliability for a new classification of lumbar disk disease.

RATIONALE AND OBJECTIVES: The nomenclature that divides disk herniations into protrusions and extrusions may increase the specificity of magnetic resonance (MR) imaging for clinically important lesions. Our goal was to determine this terminology's interreader reliability. METHODS: Three readers who were unaware of patients' histories independently read MR images of 34 consecutive patients with back pain. Readers classified disks at the lowest three lumbar levels as normal, bulging, protruded, or extruded. Kappa and weighted kappa values were the primary measures of agreement. RESULTS: Weighted kappa values showed fair-to-moderate agreement. Kappas for the dichotomous decision of extrusion present or absent were more variable, ranging from 0 to .78. Major disagreements (greater than a single category) occurred with 6.2% of all comparisons and in 10 of 34 volunteers; five involved extrusions. CONCLUSION: Overall, readers achieved moderate agreement for this new nomenclature. However, agreement for the presence or absence of an extrusion was less reliable.

Adult↗
PubMed1996

The comparison of a rapid screening MR protocol with a conventional MR protocol for lumbar spondylosis.

PURPOSE: To assess the degree of agreement between a rapid T2-weighted fast spin-echo protocol and a detailed protocol for the detection of lumbar spondylosis and to determine the sensitivity and specificity of the rapid protocol with respect to the detailed protocol. MATERIALS AND METHODS: Forty-eight patients with low back pain were studied with both a detailed four-sequence protocol and a two-sequence rapid screening protocol (acquisition time of 28 and 2.5 min for the detailed and screening protocols, respectively). The two protocol groups were numerically graded for the findings of lumbar spondylosis. RESULTS: Agreement for presence or absence of disc abnormality was 87% for the two techniques. The screening protocol showed a disc abnormality in 91% of all disc herniations and 84% of all disc bulges seen on the detailed study. All moderate and severe (grades two and three in this protocol) bulges and herniations were detected by the screening protocol. Foraminal narrowing, annular tear of the disc, degenerative changes of the facet joints, and nerve root swelling were all better shown on the detailed protocol. CONCLUSION: A rapid, two-plane, single-echo fast spin-echo sequence protocol is adequate to detect potentially significant degenerative disease of the lumbar spine. Its 2.5-min acquisition time allows a complete patient study (including patient preparation) to be performed in less than 10-15 min.

Humans↗
PubMed1995

Penetrating neck trauma: sensitivity of clinical examination and cost-effectiveness of angiography.

PURPOSE: To evaluate penetrating neck trauma for (a) sensitivity of the clinical examination as an indicator of clinically significant vascular injury, and (b) cost-effectiveness of performing screening diagnostic angiography. METHODS: The medical records of all patients with penetrating neck trauma presenting at our institution over 4 years were retrospectively reviewed. Injuries were classified into one of three anatomic zones and classified into four mutually exclusive groups based on the extent of vascular injury; (a) no vascular injury; (b) minor vascular abnormality; (c) major vascular abnormality without a change in clinical management; or (d) any injury requiring a change in clinical management. Cost data were also obtained for each patient's hospitalization. RESULTS: There were 111 patients with penetrating neck trauma. No statistically significant difference between the sensitivities of the clinical examination or angiography for the detection of vascular injury were detected. Of the 48 patients who had vascular injuries, 45 had an abnormal clinical findings (93.7% sensitivity). None of the remaining 3 patients with vascular injury and normal clinical findings would have had their treatment altered by the results of angiography. The calculated cost of using angiography as a screening tool for vascular injury in patients with normal clinical findings was approximately $3.08 million per central nervous system event prevented. CONCLUSION: Our study suggests that in patients with zone II penetrating neck injuries the clinical examination is sufficient to detect significant vascular lesions and that screening angiography may not be indicated. Because our sample size was relatively small and the mean follow-up only 13.3 days, further investigation is needed to demonstrate definitively the lack of usefulness of screening angiography.

Adolescent↗
PubMed1994

Proton MR spectroscopy of brain abnormalities in neonates born to HIV-positive mothers.

PURPOSE: To examine the sensitivity of proton MR spectroscopy for detecting early central nervous system abnormalities in neonates born to human immunodeficiency virus (HIV)-positive mothers. METHODS: Asleep, unsedated, and continuously monitored by electrocardiography, 10 newborns, 5 with HIV-positive and 5 with HIV-negative mothers, were studied within the first 10 days of life in a 1.5-T scanner. After T1- and T2-weighted images were obtained, proton spectra were performed using voxels of interest (3.4 cm3) in the deep parietooccipital white matter. Peaks were identified as N-acetyl-aspartate (2.0 ppm), creatine and phosphocreatine (3.0 ppm), choline (3.2 ppm), and inositol (3.5 ppm). Peak areas were used to calculate metabolic ratios: N-acetyl-aspartate to creatine, inositol to creatine, and creatine to choline. RESULTS: All newborns of HIV-positive mothers had abnormal proton spectra compared with control infants; a nonspecific amino acid peak in the 2.1- to 2.6-ppm area was elevated, broad, and overlapping the N-acetyl-aspartate peak in all the HIV-exposed newborns and in only 1 of the 5 control newborns. The choline-to-creatine ratio was higher in HIV-exposed newborns at 2.3 +/- 0.4 (normal term, 0.9 +/- 0.3), as was the N-acetyl-aspartate-to-creatine ratio at 2.6 +/- 0.9 (for control subjects, 1.2 +/- 0.4). MR images from these brain regions were all considered normal. Because acquired immunodeficiency syndrome develops in only a small fraction of neonates born to HIV-seropositive mothers, the above spectral abnormalities found in all our subjects may result from indirect effects of HIV, such as intrauterine growth retardation. CONCLUSIONS: These findings indicate that proton MR spectroscopy might play an important role in detecting early central nervous system complications in newborns of HIV-seropositive mothers.

AIDS Dementia Complex↗
PubMed1993

Proton MR spectroscopy of HIV-infected patients: characterization of abnormalities with imaging and clinical correlation.

The purpose of this study was to characterize the proton magnetic resonance (MR) spectroscopic findings in the brains of patients infected with human immunodeficiency virus (HIV). Peak areas were used to calculate metabolite ratios. Spectra were analyzed by blinded readers who calculated areas under metabolite peaks. MR images were evaluated by blinded readers, with both white and gray matter being rated as normal or abnormal. An aggregate index that combined N-acetylaspartate/creatine (Cr), choline/Cr, and marker peak/Cr ratios resulted in mean scores for patients and control subjects of 4.4 +/- 1.5 (standard deviation [SD]) and 2.5 +/- 0.4, respectively (P = .001). Eight of 11 patients (73%) had abnormal MR images versus four of 11 control subjects. Thirteen of 15 patient spectra (87%) were abnormal (> 2 SDs from the mean of the control subjects), while only one of 10 control spectra was abnormal. These initial results indicate that proton MR spectroscopy is a potentially useful modality for detecting HIV involvement in the central nervous system.

AIDS Dementia Complex↗
PubMed1991

Hand injuries in adults.

The radiologist plays an important role in the evaluation of hand injuries. Although the detection of fractures is important, recognition and delineation of soft tissue damage is equally vital. If only soft tissue injuries exist, plain film findings are often nonspecific. Nevertheless, they can give helpful clues in evaluating ligaments and tendons. It is especially important for the radiologist to be knowledgeable of these soft tissue injuries because, in an emergency room setting, the radiologist may be the physician most familiar with the spectrum of injuries and possible complications.

Adult↗
PubMed1991

Tension pneumothorax secondary to a gastropleural fistula in a traumatic diaphragmatic hernia.

We report a case of tension pneumothorax due to a gastropleural fistula resulting from perforation of the stomach in a traumatic diaphragmatic hernia. Awareness of perforation of strangulated stomach or bowel in a diaphragmatic hernia as a cause of pneumothorax, with or without tension physiology, in a patient with a history of trauma is important so that surgical repair can be undertaken without delay.

Adult↗
PubMed1988

Acquired immunodeficiency syndrome. Magnetic resonance patterns of brain involvement with pathologic correlation.

Magnetic resonance brain scans of 30 patients with either acquired immunodeficiency syndrome (AIDS) or AIDS-related complex were reviewed. Twenty patients had focally abnormal neurological examination results at the time of scanning. Pathological diagnosis was available in nine. Four patterns of abnormality were observed on T2-weighted images. Multiple discrete high-signal foci (pattern A) were found in patients with toxoplasmosis and progressive multifocal leukoencephalopathy. Large, bilateral patchy to confluent high-signal areas within the white matter (pattern B) represented a white matter encephalitis secondary to cytomegalovirus or human immunodeficiency virus. Generalized enlargement of the cortical sulci and ventricles (pattern C) probably reflected atrophic changes from the chronic human immunodeficiency virus infection and prolonged debilitating illness. Solitary high-signal-intensity lesions (pattern D) suggested a nonviral opportunistic infection. Differential diagnosis of brain abnormalities in patients with AIDS can be assisted by recognition of these characteristic patterns.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

High-dose cytarabine neurotoxicity: MR findings during the acute phase.

The authors report an acute cerebral and cerebellar syndrome in a patient treated with high-dose cytarabine. Diffuse high-intensity lesions in the central white matter on T2-weighted MR completely reversed with resolution of the clinical syndrome. Although the autopsy revealed cerebellar injury, the cerebral cortex was grossly and microscopically normal, consistent with a reversible process.

Acute Disease↗