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Biomedical subjects

C J Moran

Publications and source records attributed to C J Moran.

At least 55 records · Page 3Linked to original sources
PubMed1995

Role of Doppler US in screening for carotid atherosclerotic disease.

PURPOSE: To evaluate Doppler ultrasound (US) as a screening modality before arteriography for extracranial carotid artery disease. MATERIALS AND METHODS: The net benefit in stroke reduction from screening with Doppler US was calculated on the basis of literature estimates of disease prevalence, risk reduction data, and locally validated sensitivities and specificities for detection of carotid artery stenosis and occlusion in 215 patients. RESULTS: Screening a symptomatic population demonstrated a net stroke reduction. Screening asymptomatic populations with a 20% prevalence of > or = 60% stenosis also yielded a net stroke reduction. Screening low-prevalence (5%) asymptomatic populations produced a small benefit, which was lost if arteriographic or surgical complications increased slightly. Arteriographic confirmation of the US diagnosis of occlusion produced a small benefit only in the symptomatic population. CONCLUSION: Screening symptomatic and high-prevalence asymptomatic populations with US reduces stroke. Increased arteriographic or surgical complication rates reduce the benefit of screening in any population.

Arteriosclerosis↗
PubMed1995

Computer tomographic scanning within 24 hours of craniotomy for a tumor in children.

Computed tomographic (CT) brain scans were performed without and with contrast enhancement within 24 h of craniotomy in 26 patients undergoing 27 operations. Postoperative scans were retrospectively reviewed for evidence of contrast enhancement, the pattern of enhancement and the presence of blood on the postoperative scans. Contrast enhancement was seen in the resection bed in 33% of patients undergoing gross total resection of their lesions, and was absent in 50% of patients with known residual disease. Enhancement along a corticotomy was present in 18% and distant meningeal enhancement was identified in 19% of patients. These enhancement rates were unrelated to steroid dosages, duration of surgery, or the interval between operation and scanning. It was not possible to delineate residual tumor in 63% of the patients, due to a postoperative enhancement pattern that stimulated enhancing vessels, the presence of hemorrhage, or due to the absence of calcification or preoperative enhancement. None of the scans were affected by technical problems (motion artifact, inability to complete the scan) potentially associated with scanning within 24 h of craniotomy. Small amounts of residual tumor remain undetectable, particularly due to hemorrhage in the resection bed. Although no distinct advantage in defining residual disease was obtained compared to scanning at 72 h, the overall rate of findings not related to neoplasm was slightly less for scans obtained within 24 h.

Astrocytoma↗
PubMed1995

Spinal magnetic resonance imaging immediately after craniotomy for detection of metastatic disease.

Although magnetic resonance imaging (MRI) may be more sensitive than myelography with CT scanning in detecting spinal metastatic disease (SMD), the limitations of these MRI examinations have not been defined. The feasibility of obtaining early postoperative MRI to screen for SMD, and the type and frequency of imaging abnormalities were evaluated in this prospective study. Twenty-seven patients (78% with nondisseminating neoplasms or nonneoplastic diseases) were studied with postoperative spinal MRI without and with contrast enhancement, obtained within 24 h of craniotomy. Procedural problems with immediate spinal MRI were identified. Physician monitoring of the examination did not guarantee an adequate examination, and small abnormalities were missed or incompletely evaluated at the time of the MRI. Surprisingly, abnormal signal from intraspinal gas, blood, or blood breakdown products was not seen. In the absence of metastatic disease, spinal meningeal enhancement was absent. True SMD was detected, but nonneoplastic focal contrast enhancement (false positive) occurred in 11%. An unusual nonneoplastic subdural cerebrospinal fluid enhancement was seen in 3 of 13 (23%) of all patients undergoing posterior fossa craniectomies. This enhancement could hide small metastases or could be confused for SMD. Although immediate postoperative spinal MRI is potentially effective as a screening tool for the detection of SMD, we have identified some significant limitations of this technique.

Adolescent↗
PubMed1995

MR imaging of myxopapillary ependymoma: findings and value to determine extent of tumor and its relation to intraspinal structures.

OBJECTIVE: Myxopapillary ependymomas are highly vascular tumors that arise almost exclusively in the thoracolumbar region and produce symptoms that may mimic discogenic pathology. The purpose of our study was to define the typical MR features of myxopapillary ependymoma and to determine the value of MR imaging in identifying the tumor, establishing its extent, and defining its relationship to intraspinal structures. MATERIALS AND METHODS: MR studies performed on 20 patients (13 men and seven women; mean age, 35 years) with 24 pathologically proven myxopapillary ependymomas were evaluated retrospectively for size and location of lesions, expansion of the central spinal canal and neural foramina, and MR signal characteristics and enhancement patterns. T1-weighted (16 patients), proton density-weighted (15 patients), T2-weighted (14 patients), and enhanced T1-weighted (nine patients) sequences were examined. RESULTS: In all patients, masses were detected on MR images. MR imaging defined solitary masses in 17 patients and multiple lesions in three. Of the 24 tumors, MR imaging characterized 21 as predominately intradural extramedullary, two as intramedullary and intradural extramedullary, and one as extradural postsacral. Two lesions had associated syrinxes. Lesions occurred most often at the level of the L2 vertebral body, and no tumor extended above T9. Tumors spanned an average of four vertebral segments. MR imaging showed expansion of the spinal canal in five of eight tumors that extended over five or more vertebral segments. Two tumors extended into the neural foramina. The T1-weighted signal of the tumor was isointense in 12 patients, hypointense in three patients, and hyperintense in one patient. The T2-weighted signal was always hyperintense. All tumors imaged after administration of IV contrast material showed enhancement. CONCLUSION: MR imaging was valuable in identifying the extent of tumors and in defining their relationship to the intraspinal structures. Although the MR findings in myxopapillary ependymoma are nonspecific, the diagnosis can be suggested by a large, intensely enhancing, intradural extramedullary thoracolumbar mass that extends for several vertebral levels. Imaging protocols should examine the entire thoracolumbar region and include IV contrast.

Adolescent↗
PubMed1995

The effect of regular intramuscular corticosteroid therapy on bone mineral density in rheumatoid patients.

To evaluate the effect of long term regular bolus doses of intramuscular corticosteroid on bone mineral density in rheumatoid patients we undertook a retrospective cross-sectional study of 68 rheumatoid patients. Patients were divided into three groups; those who had received maintenance doses of intramuscular corticosteroid (steroid), those who had been taking regular doses of oral steroid and those who had never received steroid by either route. Bone mineral density (BMD) was measured at the hip and lumbar spine by dual photon X-ray absorptiometry (DEXA). Z scores were calculated for each patient at both sites. There is a statistical difference in Z scores at the hip in both steroid treated groups compared with the no steroid group (p < 0.001). Total steroid was less in the IM treated group compared to the oral steroid group. These results suggest that maintenance therapy with IM steroids produces significant losses of bone mineral density at the hip in rheumatoid patients and that this effect appears to be independent of the total dose.

Adrenal Cortex Hormones↗
PubMed1995

Severe thrombocytopenia following intraarterial papaverine administration for treatment of vasospasm.

Selective intraarterial infusion of papaverine is used in the treatment of symptomatic cerebral vasospasm. The authors report two episodes of severe thrombocytopenia in a patient that were related to intraarterial administration of papaverine. A 70-year-old man with a right internal carotid artery aneurysm underwent craniotomy and aneurysm clipping. He became lethargic 8 days after the hemorrhage occurred. Cerebral angiography revealed moderate vasospasm. In addition to hypervolemic-hypertensive therapy, the patient was treated on two occasions with intraarterial administration of papaverine. Within 24 hours of both treatments he developed severe thrombocytopenia. On one occasion epistaxis requiring transfusion of blood products occurred. Laboratory data support the diagnosis of immune-mediated papaverine-induced thrombocytopenia. The authors conclude that intraarterial administration of papaverine for treatment of vasospasm can be associated with severe, rapidly reversible thrombocytopenia.

Aged↗
PubMed1995

Intraoperative digital subtraction angiography: a review of 112 consecutive examinations.

PURPOSE: To examine the effect of intraoperative angiography on neurosurgery and angiographic technical success, safety, and accuracy. METHODS: Angiographic studies, surgical reports, and hospital records were reviewed retrospectively for 112 consecutive procedures in which intraoperative angiography was performed during neurosurgery. The results of conventional postoperative angiograms in 28 of the 112 procedures were also reviewed. A portable digital subtraction angiography unit was used for all patients. Decisions in the operating room were based on review of stored videotaped images. RESULTS: Eighteen studies were obtained in 14 patients after arteriovenous malformation resection. Unsuspected residual nidus was identified and resected in 3 patients. The intraoperative angiogram also altered therapy for 2 patients undergoing staged resections of arteriovenous malformations. Sixty-six studies were performed after aneurysm clipping, with clinically significant changes in surgical therapy made in 5 patients. Of 28 examinations after carotid endarterectomy, 3 led to revision. Two complications of angiography occurred. One led to a permanent neurologic deficit, yielding a complication rate of 1.5% for stroke. Two examinations could not be completed because of technical factors. Two false-negative examinations were identified on postoperative studies. One patient with a normal intraoperative study after carotid endarterectomy thrombosed the repaired internal carotid artery after surgery. CONCLUSIONS: Intraoperative angiography altered surgery in 13 of 112 procedures on 104 patients. This study supports the use of intraoperative angiography in arteriovenous malformation resection and in complex aneurysm surgery, but not for routine carotid endarterectomy.

Angiography, Digital Subtraction↗
PubMed1994

Binary nature and radiographic identifiability of craniosynostosis.

RATIONALE AND OBJECTIVES: Two independent gold standards and diagnoses from three-dimensional computed tomography (CT) images were used to examine the possibility that craniosynostosis is a binary abnormality that potentially may be diagnosed without error. METHODS: Surgical reports, histology of excised sutures, and three-dimensional CT images were compared for 25 children undergoing surgical management of craniosynostosis. Surgical reports identified sutures as normal or abnormal. Histology reported suture closure on a 5-point scale. Four radiologists used three-dimensional CT images to diagnose sutures on a 6-point rated response scale. RESULTS: Sutures with histology 0, 1, or 2 were normal on surgical reports, and those with histology 3 or 4 were abnormal. Most readers achieved nearly perfect sensitivity and specificity. Reader confidence was unrelated to degree of pathology. CONCLUSION: Craniosynostosis appears to be binary in our sample. Surgical reports, pathology results, and three-dimensional CT images read by experienced viewers achieved nearly perfect agreement.

Cranial Sutures↗
PubMed1994

Infantile meningioma.

Childhood meningiomas are unusual, and meningiomas in patients less than 1 year of age are exceedingly rare. We report a case of a meningioma with malignant histologic features in a 6-month-old child who has had an excellent postoperative course. The pathologic features in relation to prognosis, as well as the magnetic resonance imaging characteristics of the case are presented. The literature is reviewed and implications for therapeutic management are discussed.

Brain↗
PubMed1994

Craniosynostosis: diagnostic imaging with three-dimensional CT presentation.

PURPOSE: To measure diagnostic performance and preference of two three-dimensional CT reconstruction modalities (voxel-gradient and surface-projection) displayed two ways (conventional and unwrapped) in craniosynostosis confirmed by surgical inspection and histologic analysis of resected sutures. METHODS: High-resolution 2-mm contiguous CT sections were obtained and three-dimensional reconstruction images generated for 25 infants and children with skull deformities before surgical treatment of craniosynostosis. Two pediatric radiologists and two neuroradiologists first ranked images by their own preferences for diagnostic use. Then they diagnosed craniosynostosis from images presented in random order and blinded. The standard of reference was inspection during surgery and histologic evaluation of excised sutures. Finally, reviewers repeated their subjective preference tests. RESULTS: The least experienced radiologist had 100% sensitivity for all imaging modalities and specificities ranging from 43% to 83%. The two most experienced radiologists performed nearly identically, with sensitivities of 96% and specificities of 100%. After performing diagnostic tasks using all image types, all radiologists preferred conventional surface projections. CONCLUSION: Experienced readers can achieve nearly perfect diagnostic performance using the latest three-dimensional CT reconstruction images, making it a contribution to the diagnostic process. Although performance is nearly identical for all modalities, readers strongly prefer conventionally presented surface-projection images.

Algorithms↗
PubMed1993

Continuous monitoring of cerebral perfusion by thermal clearance.

Currently, no commercially available system exists to continuously monitor the effective tissue perfusion within the parenchyma of the brain. While several methods exist for accurately measuring cerebral perfusion; among them: 133xeonon clearance, hydrogen clearance and radiolabeled microsphere injection; none of these methods provides continuous monitoring. The Cook Incorporated VH8500 Volumetric Hyperthermia Treatment System (Bloomington, IN, USA) was initially developed to treat brain tumours by maintaining constant, moderate hyperthermia within a defined tissue volume over an extended duration. The system continuously adjusts the power applied to heating elements in order to maintain a constant temperature within the treatment volume. Because tissue perfusion is a primary factor responsible for removing heat from tissue, monitoring the amount of power applied to the heating elements allows one to continuously estimate tissue perfusion in the vicinity of the heating elements. In the current study, regional blood flow in the vicinity of heater/sensor catheters implanted in the brain parenchyma of three dogs was estimated by the VH8500 tissue perfusion algorithm and directly measured with radioactive labeled microspheres. The accuracy of the perfusion estimate (Thermal Perfusion Index) was evaluated by comparing these values. A range of blood flow was achieved in each animal by infusing nitroprusside. It was found that with the perfusion estimation algorithm of the Cook Incorporated VH8500 Volumetric Hyperthermia Treatment System as it is currently implemented, the Thermal Perfusion Index tended to underestimate regional perfusion as measured with radioactive microspheres, but the relationship was nearly linear. Thus, the system currently tracks changes in regional blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Design and evaluation of closed-loop feedback control of minimum temperatures in human intracranial tumours treated with interstitial hyperthermia.

The dynamic nature of blood flow during hyperthermia therapy has made the control of minimum tumour temperature a difficult task. The paper presents initial studies of a novel approach to closed-loop control of local minimum tissue temperatures utilising a newly developed estimation algorithm for use with conductive interstitial heating systems. The local minimum tumour temperature is explicitly estimated from the power required to maintain each member of an array of electrically heated catheters at a known temperature, in conjunction with a new bioheat equation-based algorithm to predict the 'droop' or fractional decline in tissue temperature between heated catheters. A closed loop controller utilises the estimated minimum temperature near each catheter as a feedback parameter, which reflects variations in local blood flow. In response the controller alters delivered power to each catheter to compensate for changes in blood flow. The validity and stability of this estimation/control scheme were tested in computer simulations and in closed-loop control of nine patient treatments. The average estimation error from patient data analysis of 21 sites at which temperature was independently measured (three per patient) was 0.0 degree C, with a standard deviation of 0.8 degree C. These results suggest that estimation of local minimum temperature and feedback control of power delivery can be employed effectively during conductive interstitial heat therapy of intracranial tumours in man.

Adult↗