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Biomedical subjects

A E Flanders

Publications and source records attributed to A E Flanders.

At least 37 records · Page 2Linked to original sources
PubMed1996

The role of magnetic resonance imaging in children with intraocular tumors and simulating lesions.

PURPOSE: To evaluate the role of pre- and post-contrast magnetic resonance (MR) studies in children with intraocular tumors and simulating lesions. METHODS: Patients younger than 12 years of age with the diagnosis of an intraocular tumor or simulating lesion with a thickness greater than 2.0 mm underwent pre- and post-contrast MR studies with surface coil. All post-contrast-enhanced images were performed with fat suppression techniques. RESULTS: There were 40 children with the clinical diagnosis of an intraocular lesion as follows: retinoblastoma (n = 22), Coats disease (n = 5), ciliary body medulloepithelioma (n = 2), primary hyperplastic persistent vitreous (PHPV) (n = 2), retinal capillary hemangioma (n = 3), massive retinal gliosis (phthisis bulbi) (n = 2), uveal melanoma (n = 1), ciliary body leiomyoma (n = 1), retinopathy of prematurity (ROP) with total retinal detachment (n = 1), and post-traumatic retinal gliosis (n = 1). In the authors' series, solid intraocular tumors greater than 2.0 mm in thickness such as retinoblastoma, ciliary body medulloepithelioma, leiomyoma, choroidal melanoma, and retinal capillary hemangioma appeared hyperintense on T1-weighted images and hypointense on T2-weighted images. Secondary serous or exudative retinal detachment, regardless of the underlying etiology (neoplasm, Coats disease, PHPV, phthisis bulbi, ROP), showed hyperintensity of the subretinal space on both T1- and T2-weighted images. Retinal gliosis was hypointense on both T1- and T2-weighted images. On contrast-enhanced T1-weighted images with fat suppression techniques, minimal to marked enhancement was observed in retinoblastoma, medulloepithelioma, retinal capillary hemangioma, leiomyoma, and choroidal melanoma. No enhancement was demonstrated in the subretinal space of Coats disease, PHPV, ROP, and in retinal gliosis. Calcification was identified in 54% of retinoblastoma tumors on MR sequences. Calcification showed low signal intensity on both T1- and T2-weighted images, with lack of enhancement on contrast-enhanced sequences, thus differentiating it from surrounding tumor or tissue necrosis. The associated serous or exudative subretinal fluid secondary to intraocular tumors or simulating lesions did not demonstrate enhancement after contrast administration, therefore differentiating it from the causative lesion. CONCLUSION: Pre- and post-contrast MR studies allowed differentiation of solid intraocular tumors such as retinoblastoma, medulloepithelioma, retinal capillary hemangioma, leiomyoma, and choroidal melanoma from intraocular lesions with primary retinal detachment such as Coats disease, PHPV, massive retinal gliosis (phthisis bulbi), ROP, and associated subretinal fluid or hemorrhage. Heterogeneity within retinoblastoma suggests foci of tumor necrosis and/or calcification. The various solid intraocular tumors were not reliably differentiated from one another based on MR features.

Child↗
PubMed1996

Performance of neuroradiologic examinations by nonradiologists.

PURPOSE: To determine the level of participation by nonradiologists in performing neuroradiologic examinations. MATERIALS AND METHODS: Medicare part B claims data from fiscal year 1992 were analyzed for CPT (current procedural terminology) codes related to computed tomography (CT) and magnetic resonance (MR) imaging of the brain, head and neck, and spine, as well as myelography, angiography, and diskography. Data were tabulated by place of service (hospital-based vs freestanding imaging centers) and by medical specialty. RESULTS: Among 363,224 Medicare claims for CT and MR imaging of the brain, head and neck, and spine, 91% of the examinations were performed in hospitals and 9% in offices or freestanding centers; 98% of studies were interpreted by a radiologist. The largest share of radiology billing by nonradiologists was from office-based or freestanding imaging centers (9%), versus 2% at hospital-based facilities. CONCLUSION: Radiologists perform the vast majority of neuroradiologic examinations. Most neuroradiologic examinations performed by nonradiologists are from neurologists at freestanding/office-based imaging centers.

Angiography↗
PubMed1996

Forecasting motor recovery after cervical spinal cord injury: value of MR imaging.

PURPOSE: To determine whether magnetic resonance (MR) imaging quantification of cervical spinal cord damage improves the prediction of motor recovery after spinal cord injury. MATERIALS AND METHODS: The extent of cervical spinal cord injury was measured on MR images obtained in 104 patients (aged 17-70 years) within 72 hours of spinal cord injury. The effects of hemorrhage and edema length on motor outcome were examined for at least 12 months. RESULTS: Patients with spinal cord hemorrhage had significantly lower upper and lower extremity motor scores at the time of injury and at 12 months than did patients without hemorrhage (P < .001). There was little recovery of lower extremity function even in patients without hemorrhage. Upper extremity motor function improved significantly in all patients (P < .001); patients without hemorrhage showed the largest improvements. The motor recovery rates for patients without hemorrhage were 0.74 (upper extremities; range, 0-1) and 0.55 (lower extremities; range, 0-1); those for patients with hemorrhage were 0.31 (range, 0-1) and 0.091 (range, 0-1). Stepwise multiple regression analyses indicated that MR information on hemorrhage and the length of edema increases the ability to predict clinical outcome by 16%-33% over that with initial clinical scores alone. CONCLUSION: An initial MR imaging evaluation of the spinal cord after spinal cord injury provides supplemental prognostic information on the recovery of motor function in the upper and lower extremities.

Adolescent↗
PubMed1996

Idiopathic acute transverse myelitis: MR imaging findings.

PURPOSE: To analyze the magnetic resonance (MR) imaging findings in idiopathic acute transverse myelitis (IATM) in relation to pathologic findings and MR findings in Guillain-Barré syndrome and ischemia. MATERIALS AND METHODS: The cases of 19 patients with IATM seen over a 4-year period were retrospectively reviewed. Clinical parameters and laboratory test findings were recorded for each patient independently of the MR findings. RESULTS: Ten (53%) patients experienced upper respiratory infection or vaccination within 4 weeks of symptom onset. The majority (82%) of cases occurred between December and May each year. In seven of 12 patients who underwent electromyography and nerve conduction examinations, evidence of peripheral nerve injury was seen. On T2-weighted axial images, 13 of 18 lesions were depicted with holocord abnormal signal intensity, seven (39%) had gray matter involvement similar to that seen in spinal cord ischemia, and three (16%) had isolated white matter involvement. Enhancement patterns varied. In three (17%) of the 18 lesions, enhancement in the cauda equina was similar to that seen in Guillain-Barré syndrome. CONCLUSION: IATM may be caused by a small vessel vasculopathy. MR findings in IATM also occasionally are similar to those described in Guillain-Barré syndrome and suggest a possible relationship.

Adolescent↗
PubMed1995

Multiple sclerosis in the spinal cord: MR appearance and correlation with clinical parameters.

PURPOSE: To determine the characteristic magnetic resonance (MR) imaging features of multiple sclerosis (MS) that affect the spinal cord. MATERIALS AND METHODS: Sixty-eight patients underwent MR imaging of the cervical and/or thoracic spine. Plaques were analyzed for lesion length, cross-sectional area and location, signal intensity, and morphology. The clinical parameters of MS type, duration of disease, sex, and age were also correlated with these MR imaging findings. RESULTS: One hundred twenty-four demyelinating plaques were found in these 68 patients; 38 had more than one plaque. The majority of plaques were two body segments in length or less and peripherally located, and occupied less than 50% of the cross-sectional area of the cord. Plaques associated with cord atrophy were more likely to occur with the relapsing-progressive form of MS. Cord swelling was found only in the relapsing-remitting form of MS. CONCLUSION: Spinal cord MS plaques are characteristically peripherally located, are less than two vertebral segments in length, and occupy less than half the cross-sectional area of the cord.

Adult↗
PubMed1995

MR imaging: quality assessment method and ratings at 33 centers.

PURPOSE: To outline a quality assessment method with peer review for magnetic resonance (MR) imaging. MATERIALS AND METHODS: Thirty-three providers in the Philadelphia area were rated on a random sample of 132 brain, 124 cervical spine, and 113 lower extremity MR imaging examinations performed during 1990. Blinded peer review was performed by panels of three subspecialty-trained academic radiologists. Technical performance, completeness, and report appropriateness of each MR imaging examination were evaluated. Aggregated scores were calculated to rate provider performance for each of the three parameters of quality. RESULTS: Two or three panelists assessed technical performance as inadequate in 15 cases, completeness as incomplete in 58 cases, and the interpretative report as inappropriate and affecting treatment in 72 cases. Eleven providers received an unsatisfactory rating on one or more parameters of quality. The association between unsatisfactory ratings and the use of low-field-strength (< or = 0.6-T) imagers was statistically significant (P < .008). CONCLUSION: Substantial deficiencies were identified in the performance of examinations and interpretation of MR images in the Philadelphia area in 1990. These findings indicate the need for a program to monitor quality of MR imaging.

Brain↗
PubMed1995

MR imaging in the diagnosis of intramedullary spinal cord diseases that involve specific neural pathways or vascular territories.

Prior to the advent of MR imaging, the internal architecture of the spinal cord could not be directly imaged. The solution of many technical problems (e.g., respiratory motion, cardiac and CSF pulsation, inadequate spatial resolution) has provided the opportunity for an increasingly refined analysis of intramedullary lesions. This article begins with a brief review of the results of high-resolution MR imaging studies of the cadaveric spinal cord. The article then focuses on MR imaging in the diagnosis of intramedullary diseases that involve specific neural pathways or vascular territories. Lesions are categorized as degenerative, inflammatory, traumatic, or ischemic. These diseases generally have distinctive clinical findings that reflect dysfunction of particular ascending sensory tracts or descending motor tracts. The corresponding abnormalities on MR images reflect the pathologic changes that occur in the affected neural pathways. Knowledge of the appearance of these diseases on MR images allows the formation of a narrow differential diagnosis and, in many cases, the confident exclusion of neoplasm as the cause of myelopathy.

Humans↗
PubMed1995

MR of malignant optic glioma of adulthood.

A case of malignant optic glioma of adulthood is imaged in its early and late stages with high-resolution MR. The images show the mass to arise from the right optic nerve before invasion of the optic chiasm.

Astrocytoma↗
PubMed1995

MR imaging in a case of postvaccination myelitis.

We describe a case of acute transverse myelitis after the administration of the recombinant form of hepatitis B vaccine. Abnormal enhancement of MR imaging accompanied residual neurologic deficit.

Adult↗
PubMed1994

The role of fat-suppression technique and gadopentetate dimeglumine in magnetic resonance imaging evaluation of intraocular tumors and simulating lesions.

OBJECTIVE: Recent studies have shown that contrast (gadopentetate dimeglumine)-enhanced magnetic resonance imaging is useful in evaluating intraocular tumors and differentiating uveal melanoma from other simulating lesions. The purpose of this study was to study prospectively the role of fat-suppression technique and gadopentetate dimeglumine-enhanced magnetic resonance imaging in the evaluation of intraocular neoplasia. PATIENTS: Forty-three uveal melanomas and 20 other simulating intraocular lesions from 63 patients were prospectively evaluated on non-contrast-enhanced and post-contrast-enhanced T1-weighted images with and without fat-suppression technique and on T2-weighted images. RESULTS: Forty-one uveal melanomas (95%) were detected with standard pulse sequences and showed the characteristic hyperintense signal on non-contrast-enhanced T1-weighted images and hypointense signal with respect to the vitreous on T2-weighted images. All 33 uveal melanomas evaluated on non-contrast-enhanced T1-weighted images with fat-suppression technique were detected on non-contrast-enhanced images with fat-suppression technique. The intensity of the signal was statistically associated with the degree of pigmentation of the tumor on T1-weighted images with fat-suppression technique (P = .03). On post-contrast-enhanced T1-weighted images with or without fat-suppression technique, the 43 uveal melanomas showed enhancement. The degree of tumor enhancement was not statistically related to the degree of tumor pigmentation or the location of the tumor. Among the other simulating intraocular lesions, choroidal metastasis, retinoblastoma, choroidal leiomyoma, and medulloepithelioma demonstrated the same features on magnetic resonance imaging studies as uveal melanoma demonstrated on non-contrast-enhanced and post-contrast-enhanced T1-weighted images with or without fat-suppression technique. In our series, choroidal hemangioma, choroidal osteoma, posterior scleritis, retinal hemangioma, and Coats' disease can be differentiated from other amelanotic intraocular tumors by their characteristics on magnetic resonance imaging studies. CONCLUSIONS: We concluded that pre-and post-contrast-enhanced T1-weighted images with fat-suppression technique are most helpful in detecting small intraocular tumors with a thickness of more than 1.8 mm and in evaluating intraocular neoplasms and simulating lesions, particularly when T2-weighted images are not available. Moreover, in juxtapapillary choroidal or retinal tumor, fat-suppression technique may help in the detection of possible optic nerve or orbital extension by improving the conspicuousness of the tumor.

Adipose Tissue↗
PubMed1994

Intramedullary causes of myelopathy.

This article addresses imaging of intramedullary processes of the spinal cord. MRI, as the procedure of choice for the intramedullary space, is the primary imaging modality that is focused on. Patterns of signal abnormality, enhancement, and morphology are described that can be used to separate neoplasms, inflammation, infarction, vascular anomalies, degenerative processes, and congenital anomalies as they affect the spinal cord. Recognition of these patterns is essential for prompt and appropriate medical and surgical treatment.

Humans↗
PubMed1994

Intradural extramedullary causes of myelopathy.

This article emphasizes the utility of contrast-enhanced MRI in the detection of intradural extramedullary causes of myelopathy. Recognition of morphological patterns, signal intensities, and enhancement patterns frequently permits a specific diagnosis or a limited differential diagnosis.

Contrast Media↗
PubMed1994

Superior sagittal sinus thrombosis in the presence of idiopathic bilateral internal jugular vein stenosis.

Cerebral venous outflow obstruction and anomalies in cerebral venous circulation predispose to dural sinus thrombosis. This case report illustrates the magnetic resonance and angiographic findings in a patient who had superior sagittal sinus thrombosis secondary to idiopathic bilateral internal jugular vein stenosis, a previously unrecognized entity. The findings suggest that bilateral stenosis of the internal jugular veins at their junction with the innominate veins causes obstruction to cerebral venous outflow leading to dural sinus thrombosis.

Constriction, Pathologic↗
PubMed1994

Metallic artifacts on MR images of the postoperative spine: reduction with fast spin-echo techniques.

PURPOSE: To determine whether the relative insensitivity of T2-weighted fast spin-echo (FSE) techniques to magnetic susceptibility can be exploited to reduce metallic artifacts on images of the postoperative spine and, thus, improve the interpretation of the postoperative study. MATERIALS AND METHODS: Three neuroradiologists retrospectively evaluated sagittal T2-weighted conventional spin-echo and FSE images obtained in 15 patients with metallic artifacts from various sources including drill particles from anterior cervical diskectomy, posterior fixation wires, fixation rods or plates, and an inferior vena cava filter. The amount of artifact present and whether these artifacts affected image interpretation were evaluated. RESULTS: Among the 45 paired evaluations, the artifact was judged to be less apparent with FSE sequences in 39. In eight of 45 evaluations (18%), the interpretation of the area of interest was possible only on the FSE images. CONCLUSION: FSE imaging, especially when performed with shorter echo spacing, increases the amount of T2-weighted information in the presence of metallic artifact because it decreases magnetic susceptibility effects.

Artifacts↗
PubMed1994

Vascular neoplasms and malformations, ischemia, and hemorrhage affecting the spinal cord: MR imaging findings.

This essay illustrates the imaging spectrum of vascular neoplasms and malformations, ischemia, and hemorrhage affecting the spinal cord. Most of these abnormalities occur far more frequently in the brain. The goal of this essay is to provide a sound anatomic and radiologic basis for the evaluation of these diseases. Knowledge of the unique cross-sectional anatomy, blood supply, and venous drainage of the spinal cord is essential in understanding the radiographic appearance of certain vascular lesions. The superior spatial resolution of fast spin-echo pulse sequences and improvements in MR angiography have expanded the role of MR imaging in the diagnosis of spinal cord diseases. These techniques are emphasized in this essay, and potential diagnostic pitfalls are highlighted. The diseases illustrated are grouped in the categories of enlarged vessels, ischemia, and hemorrhage.

Adult↗
PubMed1994

Postsurgical conjunctival epithelial cysts.

MR appearance of two patients with large, orbital conjunctival epithelium-lined inclusion cysts are presented. Both were complications of ophthalmic surgical procedures that necessitated conjunctival incision.

Adolescent↗
PubMed1993

MRI evaluation of fusion mass incorporation after anterior cervical bony fusions: preliminary findings.

While Modic has described certain MRI changes in bone grafts in patients after anterior cervical discectomy and fusion (ACF), no study has evaluated specific MRI signal changes in the fusion mass prospectively and longitudinally. The goal of the present study was to prospectively evaluate MRI changes in ACF grafts in a longitudinal fashion. Twenty-seven MRIs were included in the evaluation of seven postoperative patients. MRIs were obtained in a 1.5 tesla GE imager immediately postoperatively, and at 1, 3, and 6 months in most patients. All patients received at least three sequential MRIs. Two patients had greater than one level fused. T1 and T2 images were evaluated in all patients at each available interval. GRASS images were not found to be helpful secondary to a prohibitive amount of noise. For single level fusion masses, T1 images showed a very intense homogeneous graft signal in the immediate postoperative period which decreased slightly at 1 month. At 3 months the signal intensity of the graft was similar to the 1 month image, but was slightly less homogeneous. At 6 months, the T1 signal had greatly decreased in much of the graft. Immediate postoperative specimens showed heterogeneously high signal on T2 images which increased at 1 month in the whole graft, and then seemed to increase at the endplates while decreasing in the graft at 3 months. At 6 months the graft was becoming difficult to delineate on T2 images in many specimens. The two and three level fusions had a more heterogeneous image progression without clear evidence of solid fusion at 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervical Vertebrae↗