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Biomedical subjects

J A Arrington

Publications and source records attributed to J A Arrington.

At least 19 recordsLinked to original sources
PubMed2000

Relationship of Schmorl's nodes to vertebral body endplate fractures and acute endplate disk extrusions.

BACKGROUND AND PURPOSE: Literature regarding clinical pain syndromes associated with acute, traumatic Schmorl's nodes (SNs) is limited. Our purpose was to determine whether an SN could be related to a previous traumatic event producing either acute SN or a vertebral endplate fracture. METHODS: Two neuroradiologists independently reviewed initial and follow-up MR examinations of 14 patients with a clinical diagnosis of acute, symptomatic thoracolumbar SNs or vertebral body endplate fractures that evolved into SNs to evaluate marrow edema, signal intensity, margin definition, presence of intravertebral extruded disk material, and pattern of contrast enhancement. RESULTS: Edema of the affected vertebral body, adjacent to an endplate without wedging or collapse, was observed on the initial MR images in all cases. The initial MR images of six (43%) of 14 patients exhibited only edema of the marrow immediately adjacent to the endplate without wedging or collapse. The MR images obtained at the time of follow-up showed subsequent formation of a chronic and eventually asymptomatic SN for all six patients. The initial MR images of eight (57%) of the 14 patients showed the typical appearance of acute SNs with marrow edema of the affected vertebra. The contrast-enhanced images of three patients manifested enhancement of the invaginated disk material in three (100%) of three cases and enhancement of the surrounding vertebral body in one case (33%). Six (43%) of 14 patients had acute typical compression fracture of a vertebral body of at least one additional level. CONCLUSION: Most (57%) of the SNs in this series could be traced to episodes of significant, sudden-onset, localized, nonradiating back pain and tenderness for which the MR images showed SNs surrounded by vertebral body marrow edema. The remaining SNs (43%) were not immediately apparent as SNs and manifested only as vertebral body edema representing endplate fracture but did evolve into classical chronic SNs that follow-up imaging revealed.

Acute Disease↗
PubMed2000

Imaging of the upper airway and sinuses.

Before imaging the sinusitis patient, the clinican needs to establish diagnostic goals and be aware of the limitations of imaging. When reviewing imaging studies of the paranasal sinuses, the clinician needs a basic understanding of the anatomy of the ostiomeatal complex and sinonasal cavity, the common anatomical variants, and the typical appearances of inflammatory, infectious, and neoplastic etiologies.

Humans↗
PubMed1997

Measurement of the normal optic chiasm on coronal MR images.

PURPOSE: To develop an objective method for measuring the optic chiasm and to document its normal range in size. METHODS: Measurements of the height and area of the optic chiasm, made on coronal T1-weighted MR images with the use of commercially available region-of-interest software, were obtained in 114 healthy subjects who had a total of 123 MR studies. A normal range and standard deviation were calculated, and the information was broken down by age and sex. RESULTS: The mean area of the optic chiasm was 43.7 mm2, with a standard deviation of 5.21. The mean width was 14.0 mm, with a standard deviation of 1.68. CONCLUSION: The area and width of the optic chiasm can be measured with the use of commercially available software, which allows an objective estimate of the chiasm's size. Knowledge of the normal size range of the optic chiasm can be helpful in the early detection of some disorders.

Adolescent↗
PubMed1996

The relationship between cervical whiplash and temporomandibular joint injuries: an MRI study.

Temporomandibular joint (TMJ) symptoms are a common finding in motor vehicle accident (MVA) patients with hyperextension/hyperflexion injuries of the cervical spine (cervical whiplash). The relationship between cervical whiplash and TMJ injuries was documented with magnetic resonance imaging (MRI) in 87 consecutive MVA cervical whiplash patients who presented with TMJ symptoms and had sustained no direct trauma to the face, head or mandible and had no TMJ complaints prior to the MVA. One hundred sixty-four TMJ patients were evaluated for internal derangement, effusion and inflammation, utilizing T1 and T2 weighted images. A high percentage of the TMJ patients demonstrated abnormal findings: disk displacement with reduction (DDR), 118/164 (72%); disk displacement without reduction (DDNR), 25/164 (15%); effusion, 113/164 (69%); inflammation or edema, 84/164 (51%); total TMJ abnormalities, 156/164 (95%). The high percentage of TMJ abnormalities in this study significantly illustrates the proximate relationship between cervical whiplash and TMJ injuries.

Accidents, Traffic↗
PubMed1994

Meniscal ossification. I. Human.

Ossicles appearing in the medial menisci of three patients appeared to be post-traumatic in two and developmental in one. The histologic analysis in the two post-traumatic patients showed relatively normal bone and cartilage, but without the specific structural cartilaginous adaptations found in a naturally occurring large animal model. The third patient, with tibia vara and TAR (thrombocytopenia--absent radius) syndrome, developed the ossicle spontaneously. He is the youngest reported patient, to date, to develop this anatomic variation.

Adolescent↗
PubMed1993

MRI of soft tissue tumors.

Magnetic resonance imaging (MRI) is the only noninvasive method of defining a soft tissue tumor. The extent of the tumor and the question of involvement or noninvolvement of various adjacent tissues and structures can be determined. This information, determination of lymphatic and distant metastatic spread, is invaluable for staging and management of the disease. Whether or not the tumor type can be reliably determined, or even whether the malignant or benign nature of the tumor can be ascertained on MRI examination, is open to question. Review of the literature indicates proponents on both sides of the issue. This review illustrates the imaging features that are relevant to suggesting a histologic diagnosis, and the pitfalls that are encountered in trying to determine the malignancy or benignity of a lesion. The clinical significance of these determinations is also discussed.

Humans↗
PubMed1993

MRI: stability of three supervised segmentation techniques.

Supervised segmentation methods from three families of pattern recognition techniques were used to segment multispectral MRI data. Studied were the maximum likelihood method (MLM), k-nearest neighbors (k-NN), and a back-propagation artificial neural net (ANN). Performance was measured in terms of execution speed, and stability for the selection of training data, namely, region of interest (ROI) selection, and interslice and interpatient classifications. MLM proved to have the smallest execution times, but demonstrated the least stability. k-NN showed the best stability for training data selection. To evaluate the segmentation techniques, multispectral images were used of normal volunteers and patients with gliomas, the latter with and without MR contrast material. All measures applied indicated that k-NN provides the best results.

Adult↗
PubMed1992

Computer tomographically guided discography as a determinant of normal disc level before fusion.

Computer tomographically guided discography was used as a reproducible and reliable method of determining the internal architecture and integrity of intervertebral discs before spinal fusion operation. One hundred disc levels were studied in 60 prospective patients with 54 (54%) of levels proving abnormal. Twenty-nine levels (29% of total levels) demonstrated complete anular tears, and 25 (25% of total) showed incomplete radial tears of the anulus, often multiple, indicative of degenerative change. In each of these cases, one level higher had to be studied and was subsequently found to be normal and would, therefore, support a fusion.

Humans↗
PubMed1990

Bright lesions on sellar/parasellar T1-weighted scans.

Eighty-seven patients with sellar and parasellar pathology were evaluated by magnetic resonance imaging to categorize lesions with hyperintensity on T1-weighted images. Postoperative fat packing after transsphenoidal hypophysectomy, intratumoral subacute or chronic hemorrhage in pituitary adenomas, and hemorrhagic or fat-containing craniopharyngiomas accounted for 33 of 35 abnormalities with short T1 values. Forty-three percent of nonsurgically treated pituitary adenomas had subacute intratumoral hemorrhage present. Using T2-weighted images to distinguish fat from subacute hemorrhage and attempting to identify the normal anterior pituitary gland on T1-weighted images may help to differentiate these three entities. T1-weighted images alone were not sufficient to distinguish between all sellar and parasellar masses.

Adenoma↗
PubMed1990

Magnetic resonance imaging evaluation of congenital dislocation of the hips.

Magnetic resonance (MR) images were obtained preoperatively and postoperatively for 12 pediatric patients with congenital dislocation of the hip (CDH). The images were compared with arthrograms and computed tomography scans. The MR images were more accurate in defining soft-tissue anatomy, hip position, and obstructive factors to relocation. MR imaging is an efficient diagnostic tool in CDH.

Arthrography↗
PubMed1989

Pituitary adenomas: possible role of bromocriptine in intratumoral hemorrhage.

Magnetic resonance (MR) images of 68 patients examined for adenomas of the pituitary gland were retrospectively reviewed for the presence of hyperintensity on T1-weighted images because of recent reports suggesting that bromocriptine treatment may affect T1 values. Twenty-seven patients were examined after either surgery or radiation therapy, 29 were receiving bromocriptine, and 22 had not received any treatment at the time of MR imaging. MR imaging criteria showed evidence of subacute or chronic intratumoral hemorrhage in 18 patients, five of whom had hemorrhage proved at surgery. Ten of the 18 patients were asymptomatic from the hemorrhage; eight had headaches, visual field cuts, or cranial nerve deficits. Although an increased frequency of intratumoral hemorrhage was noted in prolactinomas and macroadenomas and in patients undergoing bromocriptine therapy, the effect of bromocriptine on bleeding was the only significant correlation (P less than .01).

Adenoma↗
PubMed1987

Childhood scoliosis: MR imaging.

The spinal cords of 28 scoliosis patients between the ages of 1 month and 17 years were examined with magnetic resonance (MR) imaging. Complete visualization was obtained in all cases. In 15 patients (53%) neuropathologic abnormalities demonstrated by MR imaging significantly affected their clinical course, including tethered cords (n = 7), syringomyelia (n = 5), Arnold-Chiari I malformation (n = 4), spinal cord tumors (n = 2), Arnold-Chiari II malformation (n = 3), and diastematomyelia (n = 1). The advantages of MR imaging in the evaluation of the scoliotic spine in children include a high sensitivity for the occult conditions associated with scoliosis, good anatomic demonstration of the cord, and absence of bone artifacts. MR imaging is recommended as a primary imaging modality in scoliosis, following conventional radiography.

Arnold-Chiari Malformation↗
PubMed1985

The sinus of the dorsum sellae.

Dissections of cadaver heads and studies of specimens sectioned in horizontal (axial), coronal, or sagittal planes at low (5 X) magnification revealed a frequent venous sinus within the bone of the dorsum sellae in addition to the true dural sinuses. This sinus interconnected the cavernous sinuses on either side of the sella turcica and was continuous with the superior and inferior petrosal sinuses and the basilar plexus. The sinus was quite evident on venograms of five patients. In sagittal sections of 37 adult cadaver heads, the sinus was identified in 28 (76%) and was absent in nine (24%) in which there was pneumatization of the dorsum sellae by the sphenoid sinus. The intracranial sinus of the dorsum sellae is not a true dural sinus but is comparable to the basivertebral veins of the spine.

Cavernous Sinus↗
PubMedDate not supplied

Unsupervised measurement of brain tumor volume on MR images.

We examined unsupervised methods of segmentation of MR images of the brain for measuring tumor volume in response to treatment. Two clustering methods were used: fuzzy c-means and a nonfuzzy clustering algorithm. Results were compared with volume segmentations by two supervised methods, k-nearest neighbors and region growing, and all results were compared with manual labelings. Results of individual segmentations are presented as well as comparisons on the application of the different methods with 10 data sets of patients with brain tumors. Unsupervised segmentation is preferred for measuring tumor volumes in response to treatment, as it eliminates operator dependency and may be adequate for delineation of the target volume in radiation therapy. Some obstacles need to be overcome, in particular regarding the detection of anatomically relevant tissue classes. This study shows that these improvements are possible.

Adult↗
PubMedDate not supplied

Thoracic outlet syndrome in a throwing athlete diagnosed with MRI and MRA.

Thoracic outlet syndrome comprises the clinical manifestations in the arm caused by compression of the neurovascular bundle as it leaves the thoracic inlet. The neurovascular bundle is composed of the subclavian artery, the subclavian vein, and the brachial plexus. The symptoms of thoracic outlet or inlet syndrome are most often caused by compression of the nerves of the brachial plexus, which is involved in up to 98% of cases; the remainder are due to vascular compression. MRI with MRA demonstrates well the anatomy of the brachial plexus as well as any vascular compression or occlusion. The relationship of the axillary and subclavian vein to the first rib and subclavius muscle also can be demonstrated. We present a college baseball player who presented with numbness in the fingers of his throwing hand when throwing a baseball. Evaluation with spin-echo and two-dimensional time-of-flight MR angiographic (MRA) imaging of the thoracic outlet region revealed obstruction of the subclavian vein with the arm abducted. To our knowledge, no such cases have been diagnosed previously with MRI.

Adult↗