Biomedical subjects

C E Spritzer

Publications and source records attributed to C E Spritzer.

At least 37 records · Page 2Linked to original sources

PubMed1995

Magnetic resonance imaging of deep venous thrombosis in pregnant women with lower extremity edema.

OBJECTIVE: To review our experience with magnetic resonance imaging (MRI) in the diagnosis of deep venous thrombosis in pregnant women. METHODS: Ten gravidas with lower extremity findings suspicious for pelvic or thigh thrombosis were examined by MRI using a gradient recalled echo technique. RESULTS: In one case, MRI confirmed pelvic extension of a femoral thrombus diagnosed by Doppler ultrasound. In a second case, MRI diagnosed thrombus isolated to the pelvis. In another, MRI detected a femoral thrombus without extension into the iliac veins. Although no thrombus was detected in the remaining seven cases, pelvic vein compression by the gravid uterus was identified in five. CONCLUSION: Magnetic resonance imaging can detect deep venous thrombosis during pregnancy and should be considered when thrombosis of the pelvic veins is a clinical consideration.

Diagnosis, Differential↗

PubMed1995

Cervical carcinoma: determination of recurrent tumor extent versus radiation changes with MR imaging.

PURPOSE: To evaluate the effectiveness of magnetic resonance (MR) imaging for assessment of the present and extent of tumor recurrence as determined with pathologic and surgical findings. MATERIALS AND METHODS: MR findings were retrospectively examined in 37 patients with a history of cervical carcinoma. Inter- and intraobserver variability was analyzed. Surgical or pathologic results were acquired in 34 of these patients; the remaining three patients were clinically followed up for at least 4 years. RESULTS: MR imaging allowed correct detection of recurrent tumor in 18 of 21 patients who had histologically documented recurrence. It helped correctly exclude recurrent disease in 15 of 16 patients. Sensitivity and specificity for detection of recurrence was 86% and 94%, respectively. Good intra- and interobserver agreement was demonstrated. CONCLUSION: MR imaging is a useful modality for differentiation of recurrent cervical carcinoma from radiation changes. Determination of the extent of recurrence with MR imaging may offer clinical assistance in the selection of optimal therapy.

Adenocarcinoma↗

PubMed1995

Changes on magnetic resonance images after traumatic hip dislocation.

Fourteen patients with traumatic hip dislocation had serial magnetic resonance imaging and routine radiographic studies from the time of injury through 24 months after injury. One experienced radiologist interpreted all images prospectively for abnormalities suggesting osteonecrosis of the femoral head and posttraumatic arthritis. Eight hips demonstrated abnormal marrow signals on T1 and T2 weighted images within 6 weeks of injury. These changes progressed in 3 hips, and osteonecrosis was confirmed subsequently by plain radiography. The abnormal marrow signals in the remaining 5 hips proved to be transient, resolving on magnetic resonance images within 3 months in 4 of the 5 patients. Magnetic resonance imaging can be used with confidence for the early detection of osteonecrosis of the femoral head after traumatic hip dislocation or fracture-dislocation. The presence of acetabular or femoral shaft hardware did not preclude magnetic resonance imaging assessment of these patients when coronal, sagittal, and axial images were obtained. Magnetic resonance imaging was not reliable for assessing marrow changes within the first week after injury, nor was it helpful in predicting which patients were at risk for posttraumatic arthritis to develop. An algorithm is proposed for using magnetic resonance imaging in the early diagnosis of osteonecrosis of the femoral head after traumatic hip dislocation.

Adolescent↗

PubMed1995

Detection of pulmonary embolism: comparison of contrast-enhanced spiral CT and time-of-flight MR techniques.

We compared the conspicuity of acute pulmonary emboli with contrast-enhanced spiral computed tomography (CT) and two- and three-dimensional time-of-flight magnetic resonance (MR) techniques. Seven dogs who received experimental pulmonary emboli and one control were imaged with spiral CT and with 2-D (FMPVAS and FASTCARD) and 3-D time-of-flight MR. Blinded, independent, prospective evaluations of the CT and MR images by two MR radiologists and two chest radiologists were then compared to the location of the emboli as determined by subsequent pathologic evaluation of the excised lungs. Embolus/blood contrast-to-noise ratios (CNRs) were calculated on both MR and CT images for pulmonary emboli that could be identified. Fifty emboli ranging from 1.0 to 5.5 mm (mean, 2.7, +/- 0.14 SEM) in diameter and from 3.0 to 60 mm (mean, 28.1 +/- 1.9 SEM) in length were found in the seven embolized dogs on pathologic examination. Three of the four radiologists identified more thrombi on CT images than they did on their best MR pulse sequence (FASTCARD) and with greater confidence. The fourth radiologist identified an equal percentage of clot on CT and FASTCARD images with confidence slightly greater on FASTCARD MR than on spiral CT. Mean CNR for the best MR technique was 43.4 (+/- 3.9 SEM) and for CT was 20.7 (+/- 1.3 SEM). In general, pulmonary emboli were detected more accurately on contrast-enhanced spiral CT than on MR. This occurred although the embolus/blood CNR was higher on MR than on CT. Better pulmonary embolus conspicuity on CT images was attributed to better spatial resolution and fewer artifacts on CT than on MR. One MR radiologist performed equally well with both spiral CT and FASTCARD techniques, suggesting that experience may be a factor in performance.

Animals↗

PubMed1994

Prospective trial of pulse oral versus intravenous calcitriol treatment of hyperparathyroidism in ESRD.

To examine the most effective route (intravenous vs. "pulse" oral), dose (physiologic vs. pharmacologic) and long-term efficacy of calcitriol therapy for secondary hyperparathyroidism in patients with end-stage renal disease (ESRD), we randomized 19 hemodialysis patients with severe hyperparathyroidism to receive over a 36-week study period either pulse orally administered calcitriol and intravenous placebo (pulse oral group; N = 9) or intravenous calcitriol and oral placebo (intravenous group; N = 10). Calcitriol was given intermittently in a double-blinded fashion at an initial dose of 2 micrograms thrice weekly and increased as tolerated up to a maximum dose of 4 micrograms per treatment. All patients received similar daily calcium supplementation (2.5 g of elemental calcium) and low dialysate calcium (1.25 mmol/liter) throughout the study period. At the maximum tolerated calcitriol dose, serum 1,25-dihydroxyvitamin D levels were significantly greater 60 minutes following intravenous (389 pmol/liter) compared to oral administration (128 pmol/liter). In spite of the different pharmacologic profiles, intravenous and oral administered calcitriol resulted in similar reductions of serum PTH over the 36 week period of observation (P = 0.300), achieving an overall maximum average PTH reduction of 43% (P = 0.016). Long-term intensive calcitriol therapy (independent of administration route), however, failed to decrease parathyroid gland size as assessed by high resolution ultrasound and/or magnetic resonance imaging. Calcitriol therapy also failed to alter the calcium sensitivity as assessed by serial PTH measurements in response to calcium loading. Increases in serum calcium, but not calcitriol dose or parathyroid gland size, predicted decrements in serum PTH, whereas hyperphosphatemia and the level of PTH suppression derived from the PTH/ionized calcium response curves predicted refractoriness to calcitriol therapy. Episodes of hypercalcemia and hyperphosphatemia were similar in both treatment groups and limited the dose of calcitriol that could be administered. These data indicate that intermittent intensive calcitriol therapy, regardless of administration route, is poorly tolerated, fails to correct parathyroid gland size and functional abnormalities, and has a limited ability to achieve sustained serum PTH reductions in end-stage renal failure patients with severe hyperparathyroidism.

Administration, Oral↗

PubMed1994

Hepatic adenoma: MR characteristics and correlation with pathologic findings.

OBJECTIVE: The purpose of this study was to describe the MR appearance of hepatic adenomas and correlate the MR imaging features with pathologic findings. MATERIALS AND METHODS: MR examinations were performed in 14 patients with 66 hepatic adenomas. The diagnosis of hepatic adenoma was proved pathologically in nine patients (22 lesions). In five other patients (44 lesions), who had type I glycogen storage disease and were known to be at risk for hepatic adenomas, the diagnosis was established by repeated sonographic examinations that showed stability, reduction, or resolution of hepatic tumors. T1- and T2-weighted spin-echo MR images obtained at 1.5 T were retrospectively reviewed for the signal intensity of the lesions relative to liver, the signal pattern, the presence of a capsule, and the presence of hemorrhage. Histopathologic specimens (22 lesions) were reviewed for fat content (graded 0-3), the presence of a capsule, and the presence of hemorrhage. RESULTS: On T1-weighted images, 51 (77%) of 66 lesions were hyperintense, 11 (17%) were hypointense, and four (6%) were isointense with respect to liver. On T2-weighted images, 49 (74%) of 66 lesions were hyperintense, 12 (18%) were isointense, and five (8%) were hypointense. Sixty-one (92%) of 66 lesions were heterogeneous. Eleven (17%) of 66 lesions were hemorrhagic. Of the 22 lesions reviewed histopathologically, 17 were hyperintense on T1-weighted images; 15 of these had a fat content of grade 2 or 3 and two had hemorrhage. All 15 lesions that had a fat content of grade 2 or 3 were hyperintense on T1-weighted images. CONCLUSION: Hepatic adenomas have a variable MR appearance but most often are hyperintense with respect to liver on T1- and T2-weighted images. The high signal intensity often relates to the increased fat content of these lesions.

Adenoma, Liver Cell↗

PubMed1993

Quantitative cerebral anatomy in depression. A controlled magnetic resonance imaging study.

Magnetic resonance imaging was used to examine cerebral anatomy in 48 inpatients with severe depression who were referred for electroconvulsive therapy and in 76 normal control subjects. The magnetic resonance imaging measures included determinations of regional cerebral volumes and ratings of the frequency and severity of cortical atrophy, lateral ventricular enlargement, and subcortical hyperintensity. The mean total frontal lobe volume was found to be 7% smaller in the inpatients with severe depression (235.88 mL) than in the normal control subjects (254.32 mL)--a difference that was statistically significant even after adjusting for the effects of age, sex, education, and intracranial size. No group differences were observed in the volumes of the cerebral hemispheres, the temporal lobes, or the amygdala-hippocampal complex, nor in the frequency of cortical atrophy. Neither did the groups differ with respect to the total volumes of the lateral and third ventricles, nor in the frequency of lateral ventricular enlargement. Patients with depression had a significantly higher frequency of subcortical hyperintensity in the periventricular white matter, with an odds ratio of 5.32.

Adult↗

PubMed1993

Magnetic resonance imaging of blood flow with a phase subtraction technique. In vitro and in vivo validation.

RATIONALE AND OBJECTIVES: One promising approach to flow quantification uses the velocity-dependent phase change of moving protons. A velocity-encoding phase subtraction technique was used to measure the velocity and flow rate of fluid flow in a phantom and blood flow in volunteers. METHODS: In a model, the authors measured constant flow velocities from 0.1 to 270.0 cm/second with an accuracy (95% confidence intervals) of +/- 12.5 cm/second. There was a linear relationship between the magnetic resonance imaging (MRI) measurement and the actual value (r2 = .99; P = .0001). RESULTS: Measuring mean pulsatile flow from 125 to 1,900 mL/minute, the accuracy of the MRI pulsatile flow measurements (95% confidence intervals) was +/- 70 mL/minute. There was a linear relationship between the MRI pulsatile flow measurement and the actual value (r2 = .99; P = .0001). In 10 normal volunteers, the authors tested the technique in vivo, quantitating flow rates in the pulmonary artery and the aorta. The average difference between the two measurements was 5%. In vivo carotid flow waveforms obtained with MRI agreed well with the shape of corresponding ultrasound Doppler waveforms. CONCLUSIONS: Velocity-encoding phase subtraction MRI bears potential clinical use for the evaluation of blood flow. Potential applications would be in the determination of arterial blood flow to parenchymal organs, the detection and quantification of intra- and extra-cardiac shunts, and the rapid determination of cardiac output and stroke volume.

Adult↗

PubMed1993

Renal magnetic resonance angiography in the preoperative detection of supernumerary renal arteries in potential kidney donors.

RATIONALE AND OBJECTIVES: Careful evaluation of the renovascular anatomy in potential living-related kidney donors is essential regarding the presence of accessory renal arteries. Conventional arteriography remains the standard of evidence for delineating the renal arterial supply. We assessed the utility of two-dimensional phase contrast (PC) magnetic resonance angiography (MRA) in the workup of potential living-related renal donors. METHODS: Thirty-nine patients were examined with conventional arteriography and MRA, which was performed on a 1.5-T system using a two-dimensional PC technique in both coronal and axial planes (repetition time[TR]/echo time [TE] = 39/8.5 msec; flip 60 degrees; matrix 256 x 128; field of view, 28 cm2; 2 excitations; first-order gradient-moment nulling; 7-mm section with 2-mm overlap). The number of hilar and polar supernumerary renal arteries was determined. Hilar supernumerary arteries were classified as co-dominant if they were similar in size to the ipsilateral main renal artery. RESULTS: Conventional arteriography identified 78 dominant and 13 supernumerary (3 co-dominant, 10 accessory) renal arteries. Magnetic resonance angiography identified the proximal 35 mm of all 78 dominant and the 3 co-dominant renal arteries. Of the remaining ten (7 polar and 3 hilar) accessory vessels, only four were correctly identified with MRA. CONCLUSION: The high error rate (60%) suggests that two-dimensional PC MRA, as implemented, should not be used in the preoperative evaluation of potential renal donors.

Adult↗

PubMed1993

Pulmonary angiography with MR imaging: preliminary clinical experience.

PURPOSE: To study the accuracy of magnetic resonance (MR) pulmonary angiography in 20 patients in whom pulmonary embolism (PE) was clinically suspected. MATERIALS AND METHODS: Fourteen patients (group 1) were recruited for the MR pulmonary angiography study before they underwent conventional pulmonary angiography (CPA) based on clinical findings. Six patients (group 2) did not undergo CPA but were considered to have PE on the basis of findings in other studies. MR venography was performed at the time of MR pulmonary angiography in 13 patients. RESULTS: MR pulmonary angiography had a sensitivity of 92%-100% and specificity of 62% for detection of PE. Performance of MR pulmonary arteriography and MR venography in a single examination to demonstrate thrombus in both the arterial and deep venous systems was proved feasible. CONCLUSION: This report describes an early clinical implementation of new MR pulmonary angiographic techniques. Further advances to improve specificity by enhancing sensitivity to slow flow and increasing spatial resolution are necessary before routine clinical use of MR pulmonary angiography is justified.

Adult↗

PubMed1993

Detection of deep venous thrombosis by magnetic resonance imaging.

OBJECTIVE: To determine the accuracy of gradient recalled echo magnetic resonance imaging in assessing deep venous thrombosis. DESIGN: This is a retrospective review of a prospective clinical experience in 216 consecutive patients studied using gradient recalled echo magnetic resonance imaging. Sixteen patients were unavailable for follow-up and 1 study was technically suboptimal, leaving 199 studies as the basis of this report. RESULTS: In 79 cases with confirmatory venography (n = 54), ultrasound (n = 16, thigh veins only), or computed tomography (n = 9, pelvic veins only), magnetic resonance imaging was 97 percent sensitive, 95 percent specific, and 96 percent accurate. Including cases that were normal by magnetic resonance imaging, not anticoagulated, and with uneventful follow-up as true normal cases, the corresponding sensitivity, specificity, and accuracy of magnetic resonance imaging were as follows: 97 percent, 98 percent, and 97 percent. CONCLUSION: Magnetic resonance imaging, using gradient recalled echo acquisitions, is capable of accurately diagnosing acute deep venous thrombosis.

Anticoagulants↗

PubMed1993

1992 ARRS Executive Council Award. Detection of deep venous thrombosis: prospective comparison of MR imaging with contrast venography.

OBJECTIVE: Preliminary reports have described the use of MR imaging for the detection of deep venous thrombosis. However, no prospective study comparing MR imaging with contrast venography (the gold standard) has been reported. Accordingly, we performed a prospective, blinded study of the efficacy of MR imaging in 61 consecutive patients with clinically suspected deep venous thrombosis. In cases of disagreement, additional testing was performed to determine the diagnosis. SUBJECTS AND METHODS: From June 1991 to February 1992, 61 patients with clinically suspected deep venous thrombosis were examined with venography and MR imaging. The average time between studies was 3 hr. In 21 of the 61 patients, the final diagnosis was deep venous thrombosis. RESULTS: For detection of deep venous thrombosis in the pelvis, the sensitivity of MR imaging was 100% (9/9) with a 95% confidence interval of 72-100% and the specificity was 95% (52/55) with a 95% confidence interval of 85-99%. In the thigh, the sensitivity (16/16) and specificity (43/43) were both 100% with 95% confidence intervals of 83-100% and 93-100%, respectively. In the calf, the sensitivity was 87% (13/15) with a 95% confidence interval of 60-98% and the specificity was 97% (36/37) with a 95% confidence interval of 86-100%. CONCLUSION: We found no statistically significant difference between MR imaging and contrast venography in the detection of deep venous thrombosis. This result suggests that MR imaging is at least as sensitive and specific as contrast venography in the detection of deep venous thrombosis.

Female↗

PubMed1993

Venography of the extremities and pelvis.

The ability of MR imaging to depict flow coupled with the inherent soft tissue contrast available on MR images has propelled this modality into the forefront of diagnostic imaging. The precise clinical utility of MR angiography is still in evolution; therefore, this article focuses on practical approaches to assessing the venous system of the extremities and pelvis.

Extremities↗

PubMed1992

Congenital aortic stenosis and patent ductus arteriosus in the adult.

Concurrent aortic stenosis and patent ductus arteriosus are not infrequent in children but are rare in adults. An adult case is described with diagnosis by cardiac catheterization and magnetic resonance imaging and with management by combined aortic valve replacement and patent ductus ligation. Review of the English-language literature produced only 8 such cases in adults, 2 of which were managed by a single-stage operation. Successful diagnosis in the adult requires careful observation at cardiac catheterization, and simultaneous valve replacement and ductus ligation may be a useful option in patient management.

Aged↗

PubMed1992

Quantitative cerebral anatomy of the aging human brain: a cross-sectional study using magnetic resonance imaging.

Seventy-six healthy adults underwent magnetic resonance imaging (1.5 T) to investigate the effects of age on regional cerebral volumes and on the frequency and severity of cortical atrophy, lateral ventricular enlargement, and subcortical hyperintensity. Increasing age was associated with (1) decreasing volumes of the cerebral hemispheres (0.23% per year), the frontal lobes (0.55% per year), the temporal lobes (0.28% per year), and the amygdala-hippocampal complex (0.30% per year); (2) increasing volumes of the third ventricle (2.8% per year) and the lateral ventricles (3.2% per year); and (3) increasing odds of cortical atrophy (8.9% per year), lateral ventricular enlargement (7.7% per year), and subcortical hyperintensity in the deep white matter (6.3% per year) and the pons (8.1% per year). Many elderly subjects did not exhibit cortical atrophy or lateral ventricular enlargement, however, indicating that such changes are not inevitable consequences of advancing age. These data should provide a useful clinical context within which to interpret changes in regional brain size associated with "abnormal" aging.

Adult↗

PubMed1992

MR imaging in adenocarcinoma of the prostate: interobserver variation and efficacy for determining stage C disease.

Patients with adenocarcinoma of the prostate confined to the gland (stage B) are candidates for a potentially curative surgical procedure (radical retropubic prostatectomy). However, patients with adenocarcinoma that penetrates the capsule or invades the seminal vesicles (stage C) are no longer considered good candidates for surgical cure of their disease. The purpose of this study was to compare the ability of four radiologists to detect stage C disease on MR images and to evaluate interobserver variability. One hundred consecutive MR studies of the prostate were reviewed independently by four radiologists to determine whether the cancer was stage C (capsule penetration or seminal vesicle invasion by tumor). A radical prostatectomy was performed in each case, and careful histologic assessment was made of the prostatic capsule and seminal vesicles for any evidence of stage C disease. The sensitivity, specificity, and accuracy (true-positive + true-negative/100 patients) in detecting stage C disease were calculated for each of the four readers. Four receiver-operating-characteristic curves were generated and compared by means of the univariate z score. Percentage agreement was calculated for five specific areas of the prostate on MR images, and observations made by the best reader were compared with the other three to help determine interreader variability. The results showed that the sensitivity and specificity of MR imaging in detecting stage C disease ranged from .24 to .61 (mean, .48) and .49 to .79 (mean, .66), respectively. The accuracy of MR imaging ranged from .47 to .61 (mean, .55). The univariate z score test showed that one of the readers significantly differed from the other three. The average percentage agreement between that reader and the other three was 70% for the five separate anatomic regions. This study shows that considerable interobserver variation exists in the interpretation of MR images for staging cancer of the prostate. The average accuracy among four radiologists in determining the presence of stage C adenocarcinoma of the prostate from MR images was only slightly above a chance guess at .55.

Adenocarcinoma↗

PubMed1992

Magnetic resonance imaging--cardiac ejection fraction measurements. Phantom study comparing four different methods.

The accuracy of cardiac ejection fraction (EF) measurements with thin, contiguous cine-magnetic resonance imaging (MR) sections is well established. Still, faster imaging and measurement techniques would be desirable. The authors evaluated the accuracy of four different MR EF measurements methods in a biventricular, anthropomorphic, foam-latex rubber phantom which was connected via noncompliant fluid-filled tubing to a pulsatile flow pump. Nine contiguous 10 mm cine-MR sections (TR/TE, 25/13; flip angle, 45 degrees) were obtained through the heart in long and short cardiac axes at 16 frames per cardiac cycle at a pump rate of 60 beats/minute. EF measurements were based on either the multi-slice summation technique (nine contiguous 10-mm sections versus four 10-mm sections spaced 10 mm apart) or the area-length method (single largest long section versus combination of largest long- and short-axis section). Three replications were performed for each of the tested EFs (40.8%, 29.4%, and 13.4%), which were compared with actual EFs. EF measurements based on contiguous 1-cm sections correlated best with the actual EFs. Average relative errors ranged from 3.2% to 6.0%. EF measurements based on every other section were less accurate; average relative errors were between 5.2% and 10.2%. Single and biplane area-length algorithm EF measurements were significantly less accurate; average relative errors were as high as 59%. EF measurements based on multi-slice summation are more accurate than those based on the area-length algorithm. Contiguous 1-cm section acquisitions are most accurate and most time consuming. With slight decrease of accuracy, acquisition and processing times can be halved by skipping every other slice.

Humans↗

PubMed1991

Brain anatomic effects of electroconvulsive therapy. A prospective magnetic resonance imaging study.

To determine prospectively whether electroconvulsive therapy (ECT) produces structural brain changes, 35 inpatients with depression underwent magnetic resonance imaging before and twice after (at 2 to 3 days and at 6 months) completion of a course of brief-pulse, bilateral ECT. The magnetic resonance images were analyzed blindly for evidence of changes in brain structure using two approaches: measurement of regional brain volumes and a pairwise global comparison. Structural brain abnormalities were present in many patients before ECT. The course of ECT produced no acute or delayed (6-month) change in brain structure as measured by alterations of the total volumes of the lateral ventricles, the third ventricle, the frontal lobes, the temporal lobes, or the amygdala-hippocampal complex. In five subjects, the pairwise global comparisons revealed an apparent increase in subcortical hyperintensity, most likely secondary to progression of ongoing cerebrovascular disease during follow-up. Our results confirm and extend previous imaging studies that also found no relationship between ECT and brain damage.

Amygdala↗