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Biomedical subjects

N E Leeds

Publications and source records attributed to N E Leeds.

At least 37 records · Page 2Linked to original sources
PubMed1995

MR of toxic effects of accelerated fractionation radiation therapy and carboplatin chemotherapy for malignant gliomas.

PURPOSE: To present MR findings of parenchymal brain injury after accelerated fractionation radiation therapy combined with carboplatin chemotherapy in the treatment of malignant brain gliomas. METHODS: Eighty-one evaluable subjects in an ongoing treatment protocol for malignant gliomas form the patient base for this report. After surgical resection of tumors, patients underwent a course of accelerated fractionation radiation therapy to a total dose of 60 Gy. Carboplatin was infused intravenously before each radiation treatment. Precontrast and postcontrast MR scans were obtained before treatment and at 4-week intervals afterward and were analyzed retrospectively. RESULTS: Posttreatment MR imaging in 20 of the 81 patients showed development of unusual parenchymal lesions or enlarging masses needing debulking, and these patients underwent second operations. Two groups emerged: those with tumor and necrotic brain (n = 11) and those with necrosis and reactive gliosis but no definitive tumor (n = 9). Enhancing lesions in the tumor-negative group appeared later than those in the tumor-positive group, were often multiple, and were usually located several centimeters away from the tumor resection site or even contralaterally. Common locations were the corpus callosum and corticomedullary junctions. Lesions in the tumor-positive group were more often solitary and located immediately adjacent to the surgical site. Positive and negative results of positron emission tomography with fludeoxyglucose F 18 were obtained in both groups. The incidence of brain necrosis without associated tumor was 11%. CONCLUSIONS: A pattern of unusual enhancing parenchymal brain lesions was seen on MR imaging after accelerated fractionation radiation therapy and concomitant carboplatin chemotherapy. The abnormalities seem more extensive than focal necrotic lesions on enhanced CT or MR imaging after conventional radiation therapy, and they may mimic recurrent tumor.

Brain↗
PubMed1994

Primary intraspinal soft-tissue sarcoma in childhood: report of two cases with a review of the literature.

Two young children who presented with lower spinal cord dysfunction manifested by bilateral leg weakness and urinary retention were diagnosed with intraspinal soft-tissue sarcoma. Neither patient had a significant extradural mass. Both tumors had histochemical features of rhabdomyosarcoma. Temporary responses were noted after combination chemotherapy either with vincristine, actinomycin D, and cyclophosphamide or with ifosfamide/mesna and etoposide. However, both patients developed uncontrollable cerebrospinal fluid (CSF) dissemination of tumor and died within 6 months of diagnosis, despite intrathecal chemotherapy and irradiation for one and very high-dose intravenous methotrexate (33 g/m2) for the other. This rare tumor can respond to parenteral antisarcoma chemotherapy, but better strategies are needed to prevent CSF spread and ultimate demise. Early institution of intrathecal cytostatic agents may retard or prevent CSF dissemination and prolong survival.

Child, Preschool↗
PubMed1994

Current imaging techniques for the evaluation of brain neoplasms.

The purpose of this article is to discuss the current imaging approaches and new techniques that have been developed in the examination and management of the patient with a brain neoplasm. These approaches and techniques include 1) functional imaging, perfusion, diffusion, localization of task activation, and dynamic circulatory changes; 2) three-dimensional imaging and techniques for tissue segmentation, surgical planning, and treatment planning; 3) positron emission tomography and single photon emission computed tomography, brain tumor diagnosis, and separation of brain tumor from radiation necrosis; 4) in vivo magnetic resonance spectroscopy, brain tumor differentiation and grading, and evaluation of the effects of therapy; and 5) future directions in the evaluation of brain neoplasms.

Brain Neoplasms↗
PubMed1994

Multiple myeloma: MR patterns of response to treatment.

PURPOSE: To assess changes in the magnetic resonance (MR) appearance of the spine in patients with multiple myeloma who responded to chemotherapy. MATERIALS AND METHODS: Twenty patients with multiple myeloma underwent MR imaging of the spine before and after chemotherapy. Sagittal T1-weighted images were obtained before and after administration of contrast material. MR patterns of marrow involvement before treatment were classified as focal, diffuse, or variegated. The changes seen on MR images after treatment were analyzed and correlated with the clinical response as defined with standard criteria. RESULTS: Patterns of complete response included resolution of marrow abnormality or persistent abnormality without enhancement or with peripheral rim enhancement. Conversion of a diffuse to a variegated or focal pattern and a decrease in the amount of marrow abnormality with persistent enhancement were observed in patients who showed a partial response. Ten patients sustained new or progressive compression fractures after successful therapy. CONCLUSION: Recognition of spinal MR patterns of response to treatment supported the occurrence of remission in patients with multiple myeloma. MR findings may help clarify response to therapy in patients with equivocal clinical changes or nonsecretory myeloma.

Adult↗
PubMed1994

Reversible neurotoxicity of interleukin-2 and tumor necrosis factor: correlation of SPECT with neuropsychological testing.

A 41-year-old man developed subacute neurotoxicity associated with interleukin-2 and tumor necrosis factor therapy for metastatic renal cell carcinoma. Cognitive deficits revealed on neuropsychological testing and frontal lobe perfusion deficits revealed on SPECT resolved after 1 month. Findings suggest possible neuroanatomic and physiologic substrates of cytokine neurotoxicity.

Adult↗
PubMed1993

Imaging patterns of multifocal gliomas.

We reviewed the imaging characteristics of 51 consecutive cases of cerebral glioma with multiple foci of involvement. In 26 patients, multifocality was present at the initial diagnosis, whereas in 25, it developed at a later stage. Thirty-two patients were studied with MRI, 13 with CT, and six with both imaging techniques. In 14 cases, no apparent dissemination route was identified; these tumors were presumed to be true multicentric gliomas. In the rest of the cases, various patterns of spread from a primary site were evident or suggested, and the tumors were denoted as multifocal. The most frequent dissemination route in the latter group was the meningeal-subarachnoid space, followed by the subependymal, intraventricular route and direct brain penetration. Multifocal gliomas are more frequent than generally believed and, therefore, multiple cerebral masses should be thoroughly evaluated and not always presumed to be of metastatic origin.

Brain↗
PubMed1993

Waldenström macroglobulinemia: MR imaging of the spine and CT of the abdomen and pelvis.

Twenty-three consecutive patients with Waldenström macroglobulinemia were studied with magnetic resonance (MR) imaging of the spine and computed tomography (CT) of the abdomen and pelvis. MR imaging studies included sagittal T1-weighted and gradient-recalled-echo sequences performed with and without contrast material enhancement. Marrow involvement was identified with MR imaging in 21 of 23 (91%) patients. Diffuse involvement was noted in 13 patients (56%), and a variegated pattern in eight (35%). CT demonstrated enlarged nodes in 10 of 23 (43%) patients. Correlation of MR imaging patterns and presence of adenopathy at CT with standard laboratory values for Waldenström macroglobulinemia revealed an association of the diffuse MR imaging pattern of marrow involvement and the presence of enlarged nodes at CT with more advanced disease. MR imaging of the spine and CT are reliable means of evaluation of disease status in Waldenström macroglobulinemia. They may be employed as additional means in the staging of Waldenström macroglobulinemia and may be helpful in the follow-up of patients with this rare hematologic malignancy.

Abdomen↗
PubMed1992

Multiple myeloma: spinal MR imaging in patients with untreated newly diagnosed disease.

Spinal magnetic resonance (MR) imaging was performed in 29 patients with newly diagnosed, untreated multiple myeloma. Nineteen (66%) patients were asymptomatic. Sagittal pre- and postcontrast T1-weighted spin-echo images and gradient-recalled-echo images of the thoracic and lumbosacral spine were obtained. Marrow involvement was identified in 20 (69%) patients. There were three MR patterns: focal lesions in nine patients (31%), diffuse involvement in seven (24%), and an inhomogeneous pattern of tiny lesions on a background of normal marrow in four (14%). A statistically significant correlation between MR imaging patterns of marrow involvement and serum hemoglobin values (one-way, P = .0899; Kruskal-Wallis, P = .0620) and between MR imaging patterns and percentage of marrow plasmacytosis (Kruskal-Wallis, P = .0314) was noted, with patterns of diffuse and focal marrow involvement associated with more abnormal values. Spinal MR imaging in patients with early myeloma may reveal marrow involvement in both symptomatic and asymptomatic patients. Some correlation was found between MR imaging patterns and laboratory indexes of disease.

Adult↗
PubMed1991

Diagnostic imaging advances in neurooncology.

As we move into the 1990s, the field of diagnostic imaging displays greater usefulness as a result of continued technical improvements in existing modalities and the discovery of new techniques. Magnetic resonance (MR) imaging is now, without question, the imaging modality of choice for evaluation of tumors of the brain and spine. The general availability of the MR imaging contrast agent, gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA), for the last three years has greatly expanded the role of MR imaging. Progress in metabolic imaging and MR spectroscopy may offer yet greater understanding of the physiology of brain tumors and has application for the diagnosis and posttreatment follow-up of these patients. These topics will be addressed in this review, which spans the years 1989 and 1990.

Brain Neoplasms↗
PubMed1991

Neuroradiology.

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Brain Diseases↗
PubMed1990

Radiology.

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Radiology↗
PubMed1990

Verbal asomatognosia.

Verbal asomatognosia is a form of neglect in which a patient denies ownership of a limb contralateral to a brain lesion. To establish the neuroanatomic substrate of this syndrome, we analyzed the CTs of 12 right-hemisphere stroke patients with neglect and verbal asomatognosia and 4 patients with neglect but without asomatognosia. Of 16 cortical and subcortical brain regions analyzed, supramarginal gyrus and its subcortical connections within posterior corona radiata were most consistently involved in the asomatognosia cases. One or both of these regions were spared in all cases of neglect without asomatognosia. Our data confirm Nielsen's localization of asomatognosia to the right supramarginal gyrus and thalamoparietal peduncle. Converging lines of evidence from experiments in humans and monkeys suggest that damage to area PF may be necessary for the production of personal neglect of a limb.

Body Image↗
PubMed1990

The clinical application of radiopharmaceuticals.

This article highlights the choices and the arguments in the selection of appropriate contrast materials in radiological examinations--nonionic versus ionic contrast material--and aims to assist the physician in decision-making. Various authors have raised questions concerning the proposed advantages of nonionic contrast material. However, studies in low risk patients have shown more complications with the use of ionic contrast than nonionic contrast materials; this is the important group of patients since in high risk patients nonionics are used almost exclusively. The important factor that increases the controversy is cost, which is significant since nonionic agents cost 10 to 15 times more than ionic agents in the USA. Thus, cost-benefit considerations are important because price sensitivity and cost may determine fund availability for equipment or materials that also may be necessary or important in improving patient care. In magnetic resonance imaging (MRI), as in computed tomography (CT), the use of contrast material has improved diagnostic accuracy and the ability to reveal lesions not otherwise easily detected in brain and spinal cord imaging. These include separating scan from disc, meningitis, meningeal spread of tumour, tumour seeding, small metastases, intracanalicular tumours, separating major mass from oedema, determining bulk tumour size and ability to demonstrate blood vessels so dynamic circulatory changes may be revealed.

Humans↗
PubMed1989

Radiology.

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Humans↗
PubMed1989

MR imaging of the ankle: normal variants.

Thirty asymptomatic ankles were studied with high-resolution surface coil magnetic resonance (MR) imaging to identify normal structures. Several normal variants were demonstrated, including (a) Cortical irregularity of the posterior tibiotalar joint (should not be mistaken for osteonecrosis) in 27 of 30 cases; (b) normal posterior talofibular ligament with irregular and frayed superior edge simulating a tear in 13 of 30 cases; (c) normal navicular insertion of the posterior tibial tendon with heterogeneous signal intensity in 14 of 30 cases; (d) deltoid ligament inhomogeneity in seven of ten cases; and (e) fluid in the shared peroneal tendons sheath (may be confused with a longitudinal tendon tear) in three of 30 cases. Ankle imaging with the use of MR is still a relatively new procedure. Further investigation is needed to better define normal anatomy and normal variants.

Adolescent↗
PubMed1988

Rupture of posterior tibial tendon: CT and MR imaging with surgical correlation.

Computed tomography (CT) and magnetic resonance (MR) imaging were performed in 32 cases of clinically suspected chronic tears of the posterior tibial tendon. Surgery was performed in 22 patients (69%). Each case was classified radiographically and surgically as normal or a type 1, type 2, or type 3 rupture. The sensitivity and specificity of CT were 90% and 100%, respectively, while those of MR imaging were 95% and 100%. The accuracy in detecting ruptures was 91% for CT and 96% for MR imaging. The overall accuracy, which reflected the percentage of cases correctly diagnosed as well as those correctly classified, was 59% for CT and 73% for MR imaging. Although the differences between the CT and MR imaging parameters were not statistically significant (possibly due to the small population), the results suggest that MR imaging is the method of choice for detecting ruptures of the posterior tibial tendon. MR imaging provided greater definition of tendon outline, vertical splits, synovial fluid, edema, and degenerated tissue. CT was superior to MR imaging in showing associated bone abnormalities such as periostitis, subtalar osteoarthritis, and subtalar dislocation.

Adult↗
PubMed1987

Computed tomography guidance for skeletal biopsy.

Computed tomographic (CT) guided biopsy and abscess drainage of multiple organ systems have been well described. Reports of spinal and skeletal applications have been less common. This study describes the use of CT guidance in the biopsy of various skeletal lesions in 46 patients. Forty-one patients had skinny needle aspirations (18 or 22 gauge) and 23 patients had trephine core biopsies. Sites of the lesions included: thoracic spine-15 patients, lumbosacral spine-17 patients, bony pelvis-6 patients, rib-2 patients, and long bones-6 patients. Fast scanners capable of rapid image reconstruction have overcome many constraints. With CT guidance, the physician who performs the procedure receives virtually no ionizing radiation. The exact location of the needle tip is accurately visualized in relation to the lesion being biopsied and to the vital organs.

Biopsy, Needle↗