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Biomedical subjects

G R Caputo

Publications and source records attributed to G R Caputo.

At least 19 recordsLinked to original sources
PubMed1999

Metastatic head and neck cancer: role and usefulness of FDG PET in locating occult primary tumors.

PURPOSE: To assess the usefulness of 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) of the head and neck in locating occult primary lesions in patients with metastatic cervical adenopathy. MATERIALS AND METHODS: Seventeen patients with metastatic cervical adenopathy of unknown primary origin were referred for FDG PET of the head and neck. All patients had undergone correlative anatomic imaging within 1 month of FDG PET. Surgical, clinical, and histopathologic findings were used to assess the performance of FDG PET. RESULTS: Increased apical lung uptake at FDG PET led to a biopsy-proved diagnosis of primary lung cancer in two patients. Of the remaining 15 patients, 10 had a focus of increased activity; directed biopsy of these sites led to confirmation of a primary carcinoma in seven patients. Correlative anatomic imaging failed to demonstrate the primary sites of disease in two of these seven patients. None of the five patients with negative FDG PET studies have manifested evidence of a primary site of disease during follow-up of 8-42 months (mean, 29 months). CONCLUSION: FDG PET allows effective localization of the unknown primary site of origin in metastatic head and neck cancer and can contribute substantially to patient care.

Adenocarcinoma↗
PubMed1998

Clinical utility of positron emission tomography with 18F-fluorodeoxyglucose in detecting residual/recurrent squamous cell carcinoma of the head and neck.

PURPOSE: The use of positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) to detect residual/recurrent squamous cell carcinoma of the head and neck has been tested only in small groups of patients. Our purpose, therefore, was to evaluate the ability of this technique to detect the presence of tumor at both primary and nodal sites in a large cohort of patients. METHODS: All patients referred for PET scanning over a 2.5-year period with a question of residual or recurrent squamous cell carcinoma of the head and neck were identified. Thirty-five of 44 patients had sufficient follow-up to be meaningful to our analysis (range, 6-33 months). PET scans were interpreted visually with knowledge of the clinical history and correlative anatomic imaging findings. Detection of disease involving primary and nodal sites was assessed independently. Additionally, because each patient had been referred in an attempt to resolve a specific clinical problem, the usefulness of PET in accurately addressing these questions was assessed. RESULTS: At the primary site, sensitivity and specificity for residual/recurrent disease were 100% and 64%, respectively; for nodal disease, sensitivity and specificity were 93% and 77%, respectively. In helping to resolve the clinical question being asked, the positive predictive value of the test result was 65% and the negative predictive value was 91%. CONCLUSION: The high sensitivity and negative predictive value of PET scanning in our cohort of patients suggest an important role for this technique in the care of patients with suspected residual/recurrent head and neck carcinoma. The lower figures obtained for specificity and positive predictive value reflect the fact that increased FDG uptake may be due to either tumor or inflammation.

Adult↗
PubMed1996

Magnetic resonance imaging of acquired cardiac disease.

Over the last 15 years, advances in magnetic resonance imaging techniques have increased the accuracy and applicability of cardiovascular magnetic resonance imaging. These advances have improved the utility of magnetic resonance imaging in evaluating cardiac morphology, blood flow, and myocardial contractility, all significant diagnostic features in the evaluation of the patient with acquired heart disease. Utilization of cardiovascular magnetic resonance imaging has been limited, primarily due to clinical reliance upon nuclear scintigraphy and echocardiography. Recent developments in fast and ultrafast imaging should continue to enhance the significance of magnetic resonance imaging in this field. Widespread use of magnetic resonance imaging in the evaluation of the cardiovascular system will ultimately depend upon its maturation into a comprehensive, noninvasive imaging technique for the varying manifestations of acquired heart disease, including cardiomyopathy, ischemic heart disease, and acquired valvular disease.

Aorta, Thoracic↗
PubMed1995

Evaluation of mitral stenosis with velocity-encoded cine-magnetic resonance imaging.

Velocity-encoded cine-magnetic resonance imaging (VEC-MRI) is a new method for quantitation of blood flow with the potential to measure high-velocity jets across stenotic valves. The objective of this study was to evaluate the ability of VEC-MRI to measure transmitral velocity in patients with mitral stenosis. Sixteen patients with known mitral stenosis were studied. A 1.5 Tesla superconducting magnet was used to obtain velocity-encoded images in the left ventricular short-axis plane. Images were obtained throughout the cardiac cycle at 3 consecutive slices beginning proximal to the mitral coaptation point. To determine the optimal slice thickness for MRI imaging, both 10 mm and 5 mm thicknesses were used. Echocardiography including continuous-wave Doppler was performed on every patient within 2 hours of MRI imaging. Peak velocity was determined for both VEC-MRI and Doppler-echo images. Two observers independently measured the VEC-MRI mitral inflow velocities. Of the 16 patients, imaged data were incomplete in only 1 study, and all images were adequate for analysis. Strong correlations were found for measurements of mitral valve gradient for both 10 mm (peak r = 0.89, mean r = 0.84) and 5 mm (peak r = 0.82, mean r = 0.95) slice thicknesses. Measurements of peak velocity with VEC-MRI (10 mm) agreed well with Doppler: mean 1.46 m/s, mean of differences (Doppler MRI) 0.38 m/s, standard deviation of differences 0.2 m/s. These findings suggest that VEC-MRI can noninvasively determine the severity of mitral stenosis.

Adult↗
PubMed1994

Quantification of mitral regurgitation by velocity-encoded cine nuclear magnetic resonance imaging.

OBJECTIVES: The feasibility of velocity-encoded cine nuclear magnetic resonance (NMR) imaging to measure regurgitant volume and regurgitant fraction in patients with mitral regurgitation was evaluated. BACKGROUND: Velocity-encoded cine NMR imaging has been reported to provide accurate measurement of the volume of blood flow in the ascending aorta and through the mitral annulus. Therefore, we hypothesized that the difference between mitral inflow and aortic systolic flow provides the regurgitant volume in the setting of mitral regurgitation. METHODS: Using velocity-encoded cine NMR imaging at a magnet field strength of 1.5 T and color Doppler echocardiography, 19 patients with isolated mitral regurgitation and 10 normal subjects were studied. Velocity-encoded cine NMR images were acquired in the short-axis plane of the ascending aorta and from the short-axis plane of the left ventricle at the level of the mitral annulus. Two independent observers measured the ascending aortic flow volume and left ventricular inflow volume to calculate the regurgitant volume as the difference between left ventricular inflow volume and aortic flow volume, and the regurgitant fraction was calculated. Using accepted criteria of color flow Doppler imaging and spectral analysis, the severity of mitral regurgitation was qualitatively graded as mild, moderate or severe and compared with regurgitant volume and regurgitant fraction, as determined by velocity-encoded cine NMR imaging. RESULTS: In normal subjects the regurgitant volume was -6 +/- 345 ml/min (mean +/- SD). In patients with mild, moderate and severe mitral regurgitation, the regurgitant volume was 156 +/- 203, 1,384 +/- 437 and 4,763 +/- 2,449 ml/min, respectively. In normal subjects the regurgitant fraction was 0.7 +/- 6.1%. In patients with mild, moderate and severe mitral regurgitation, the regurgitant fraction was 3.1 +/- 3.4%, 24.5 +/- 8.9% and 48.6 +/- 7.6%, respectively. The regurgitant fraction correlated well with the echocardiographic severity of mitral regurgitation (r = 0.87). Interobserver reproducibilities for regurgitant volume and regurgitant fraction were excellent (r = 0.99, SEE = 238 ml; r = 0.98, SEE = 4.1%, respectively). CONCLUSIONS: These findings suggest that velocity-encoded NMR imaging can be used to estimate regurgitant volume and regurgitant fraction in patients with mitral regurgitation and can discriminate patients with moderate or severe mitral regurgitation from normal subjects and patients with mild regurgitation. It may be useful for monitoring the effect of therapy intended to reduce the severity of mitral regurgitation.

Adult↗
PubMed1994

Evaluation of left atrial contribution to left ventricular filling in aortic stenosis by velocity-encoded cine MRI.

Velocity-encoded cine MRI (VEC-MRI) can measure volume flow at specified site in the heart. This study used VEC-MRI to measure flow across the mitral valve to compare the contribution of atrial systole to left atrial filling in normal subjects and patients with left ventricular hypertrophy. The study population consisted of 12 normal subjects (mean age 34.5 years) and nine patients with various degrees of left ventricular hypertrophy resulting from aortic stenosis (mean age 70 years). VEC-MRI was performed in double-oblique planes through the heart to measure both the mitral inflow velocity pattern (E/A ratio) and the volumetric flow across the mitral valve. The left atrial contribution to left ventricular filling (AC%) was calculated. The results were compared with Doppler echocardiographic parameters. The VEC-MRI-derived mitral E/A ratios showed a significant linear correlation with E/A ratios calculated from Doppler echocardiography (r = 0.94), and the VEC-MRI-derived E/A ratios (2.1 +/- 0.5 vs 1.0 +/- 0.4) and AC% values (24.9 +/- 7.2 vs 45.7 +/- 16.4) were significantly different between normal subjects and patients with aortic stenosis (p < 0.01 in both groups). The same differences were seen in the Doppler echocardiographic parameters. The VEC-MRI-derived E/A ratio and AC% showed significant hyperbolic and linear correlations with left ventricular mass indexes (r = 0.95 and 0.86). In addition, the VEC-MRI-determined E/A ratio and the volumetric AC% displayed a highly significant hyperbolic correlation (r = 0.95). Thus VEC-MRI can be used to evaluate left ventricular diastolic filling characteristics in normal subjects and patients with abnormalities of diastolic filling.

Adult↗
PubMed1994

Breath-hold MR cine angiography of coronary arteries in healthy volunteers: value of multiangle oblique imaging planes.

OBJECTIVE: Breath-hold MR cine angiography was used to depict the coronary arteries in healthy volunteers. Multiangle oblique imaging planes were evaluated for feasibility in showing continuous segments of the proximal and middle portions of the left anterior descending and right coronary arteries. SUBJECTS AND METHODS: Eighteen healthy subjects were examined with a 1.5-T MR imager. Fat-suppressed fast gradient-echo images (TR = 9.8 msec, TE = 3.5 msec) were acquired with a 13-cm receive surface coil. A segmented k-space data acquisition was used to obtain images of the coronary arteries at several phases of the cardiac cycle within a single breath-hold. Multiangle double oblique images that were tangential and sequential to the epicardial surface of the left ventricle were used to show the left anterior descending artery, and oblique coronal images were used to show the right coronary artery. Images of consecutive slice locations were shown in a cine format, and the length of each major coronary artery that was continuously visualized was measured. RESULTS: The left main coronary artery, proximal left anterior descending artery, and right coronary artery were demonstrated in all subjects. The mid and distal portions of the left anterior descending artery and diagonal branches were visualized best on multiangle oblique imaging planes. Continuous segments (> 6 cm) of the left anterior descending artery and right coronary artery were imaged in 14 subjects (78%) and 12 subjects (67%), respectively. Cine display was useful for showing the continuity of the coronary arterial segments and also for distinguishing arteries from veins. CONCLUSION: Double oblique imaging planes were useful in showing long segments of left anterior descending and right coronary arteries on coronary MR angiograms. Further work is necessary to improve detection of the left circumflex artery.

Adult↗
PubMed1993

The clinical spectrum of patients with aneurysms of the ascending aorta.

Aneurysms of the ascending aorta are often unsuspected, yet they can quickly lead to death from aortic rupture or dissection. To examine the clinical spectrum of patients with aneurysms of the ascending aorta, we searched the University of California, San Francisco (USCF) Echocardiography Data Base for all patients with aneurysms of the ascending aorta (> or = 5.0 cm in diameter) seen over a 7-year period. The echocardiograms and clinical courses of these patients were then reviewed. We identified 15 patients with aneurysms of the ascending aorta: five had aneurysms > 7.0 cm in diameter, three had aneurysms 6.0 to 6.9 cm, and seven had aneurysms 5.0 to 5.9 cm in diameter. Among the five patients < 50 years of age, four had Marfan's syndrome, and among the 10 patients > or = 50 years of age, eight had evidence of atherosclerotic vascular disease. At presentation, 13 patients had nonspecific symptoms, and two were asymptomatic. Echocardiography demonstrated that 12 patients had at least mild aortic insufficiency and that five had aortic dissections. One of the seven patients who underwent surgical resection died of an intraoperative cardiac arrest, and two of the eight patients treated medically died within 1 week of presentation. We conclude that the clinical spectrum of patients with aneurysms of the ascending aorta is wide. Because these aneurysms are often unsuspected, physicians should have a low threshold for imaging the ascending aorta in patients with Marfan's syndrome or atherosclerotic vascular disease, particularly when aortic insufficiency is present.

Adult↗
PubMed1993

Quantification of the left ventricular volumes and function with cine MR imaging: comparison of geometric models with three-dimensional data.

Acquisition and measurement of left ventricular (LV) volumes with a three-dimensional data set of cine magnetic resonance (MR) images from apex to base is a time-consuming process. Results of a study with 10 healthy volunteers and 10 patients with LV hypertrophy were prospectively evaluated. The heart was shown in the anatomic short- and horizontal long-axis planes with cine MR imaging. LV volumes were measured with various geometric models, and ejection fractions were calculated. In both groups, the values of LV stroke volume obtained with a modified Simpson rule and biplane ellipsoid models correlated well to the analysis of the three-dimensional data set of cine MR images. There were no significant differences for the calculated ejection fraction between values obtained with the modified Simpson rule or the biplane ellipsoid model versus the three-dimensional data set. A high inter-observer reproducibility of cine MR measurements with the two former models was found. Therefore, modified Simpson rule and biplane ellipsoid models, with their shorter acquisition and processing times, may increase the clinical utility of cine MR imaging.

Adult↗
PubMed1993

Evaluation of left ventricular volume and mass with breath-hold cine MR imaging.

Left ventricular (LV) volumes and mass were evaluated in 10 healthy volunteers with breath-hold cine magnetic resonance (MR) imaging. The results were compared with those obtained with conventional cine MR imaging. The breath-hold studies showed no ghosting artifact, and cardiac edges were clearly identified because of the reduced blurring. Measurements of LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV mass obtained with breath-hold cine MR imaging showed close correlation with those obtained with conventional cine MR imaging (r = .98, .97, and .99, respectively). The interobserver variabilities for LVEDV, LVESV, and LV mass determined with breath-hold cine MR imaging (4.0%, 8.0%, and 3.7%, respectively) were equal to or less than those determined with conventional cine MR imaging (4.0%, 8.6%, and 5.0%, respectively). The authors conclude that breath-hold cine MR imaging is highly useful because an accurate assessment of cardiac function is obtained in less than 5 minutes.

Adult↗
PubMed1993

MR imaging of the myocardium using nonionic contrast medium: signal-intensity changes in patients with subacute myocardial infarction.

OBJECTIVE: Gadodiamide injection (Omniscan, Sanofi Winthrop Pharmaceuticals, New York) is a new nonionic MR contrast medium that has been shown in animal studies to provide persistent differential enhancement of myocardial infarction. Because differential enhancement of normal and infarcted myocardium may be useful for the diagnosis and sizing of myocardial infarctions, we assessed the effectiveness of gadodiamide injection in enhancing signal-intensity differences between infarcted and normal myocardium on spin-echo T1-weighted images. SUBJECTS AND METHODS: Signal intensity of normal and infarcted myocardium, contrast ratio, contrast-to-noise ratio, and signal-to-noise ratio were measured in 12 patients with subacute myocardial infarction (mean, 16 days after diagnosis) before and after injection of contrast medium. Precontrast T1-weighted and T2-weighted images were obtained with a 1.5-T MR imager. T1-weighted images were acquired 5, 15, and 30 min after gadodiamide injection (0.2 mmol/kg) and T1-weighted images with fat saturation were acquired 10 min after gadodiamide injection. RESULTS: Gadodiamide injection significantly increased signal intensity of normal (34 +/- %) and infarcted (90 +/- %) myocardium compared with their signal intensities on precontrast T1-weighted images. The contrast ratio was significantly increased, and the augmented ratios persisted throughout the 45-min observation period. The contrast ratio on T2-weighted images was comparable to that on contrast-enhanced T1-weighted images (with or without the use of fat saturation). However, the signal-to-noise and contrast-to-noise ratios of T2-weighted images were significantly lower than those of contrast-enhanced T1-weighted images. The maximum contrast-to-noise ratio for visualizing myocardial infarction was achieved on contrast-enhanced T1-weighted images with fat saturation. CONCLUSION: Improved and persistent contrast between infarcted and normal myocardium can be produced on MR images by injecting gadodiamide at a dose of 0.2 mmol/kg, which provides prolonged delineation of myocardial infarctions. Maximum contrast-to-noise ratios for detecting myocardial infarction can be produced by using fat-saturated T1-weighted imaging after a high dose of this nonionic contrast medium has been administered.

Adult↗
PubMed1993

Role of MR imaging in acquired and congenital cardiovascular disease.

The use of MR imaging for noninvasive cardiac diagnosis is still limited because clinicians currently rely on echocardiography and nuclear scintigraphy. Because of the development of MR techniques that can be used to evaluate contractile function and blood flow as well as cardiac morphology, greater applications of MR imaging are now likely to occur. Such a multifaceted use of MR imaging for the evaluation of cardiovascular disease should be encouraged by the continued development of fast imaging techniques. The purpose of this review is to describe the current clinical applications of MR imaging in acquired and congenital heart disease. The widespread use of MR imaging for cardiovascular diagnosis ultimately depends on its suitability as a comprehensive noninvasive imaging technique for ischemic heart disease and as a replacement for cardiac catheterization in congenital heart disease.

Aortic Diseases↗
PubMed1993

Magnetic resonance angiography and blood flow quantification.

A variety of magnetic resonance (MR) techniques are available for flow imaging and quantification, each exploiting a different property of flowing blood to achieve contrast with stationary tissue, and each with its own strengths and limitations dependent on the flow conditions. These same techniques have been used to perform MR angiography of peripheral as well as the coronary arteries. This article provides an overview of MR angiographic and blood flow quantification techniques and their clinical application. Future technical advances in MR in concert with continuing developments in computer software and hardware are likely to make MR a major vascular technique in the coming decade.

Blood Flow Velocity↗
PubMed1992

Quantification of left to right atrial shunts with velocity-encoded cine nuclear magnetic resonance imaging.

OBJECTIVES: The purpose of this study was to evaluate the ability of velocity-encoded nuclear magnetic resonance (NMR) imaging to quantify left to right intracardiac shunts in patients with an atrial septal defect. BACKGROUND: Quantification of intracardiac shunts is clinically important in planning therapy. METHODS: Velocity-encoded NMR imaging was used to quantify stroke flow in the aorta and in the main pulmonary artery in a group of patients who were known to have an increased pulmonary to systemic flow ratio (Qp/Qs). The velocity-encoded NMR flow data were used to calculate Qp/Qs, and these values were compared with measurements of Qp/Qs obtained with oximetric data derived from cardiac catheterization and from stroke volume measurements of the two ventricles by using volumetric data from biphasic spin echo and cine NMR images obtained at end-diastole and end-systole. RESULTS: Two independent observers measured Qp/Qs by using velocity-encoded NMR imaging in 11 patients and found Qp/Qs ranging from 1.4:1 to 3.9:1. These measurements correlated well with both oximetric data (r = 0.91, SEE = 0.35) and ventricular volumetric data (r = 0.94, SEE = 0.30). Interobserver reproducibility for Qp/Qs by velocity-encoded NMR imaging was good (r = 0.97, SEE = 0.20). CONCLUSIONS: Velocity-encoded NMR imaging is an accurate and reproducible method for measuring Qp/Qs in left to right shunts. Because it is completely noninvasive, it can be used to monitor shunt volume over time.

Adolescent↗
PubMed1992

Measurement of right ventricular mass in normal and dilated cardiomyopathic ventricles using cine magnetic resonance imaging.

The accurate quantification of right ventricular (RV) mass has eluded conventional imaging modalities. Accordingly, cine magnetic resonance imaging was used for quantification of RV as well as left ventricular (LV) mass in 10 normal subjects and in 10 patients with dilated cardiomyopathy with an LV ejection fraction less than 0.40. Hearts were imaged with 10 mm thick short-axis slices from apex to base with a short echo delay time of 5 ms. Each slice was partitioned into 3 sections: RV free wall, ventricular septum and LV free wall, for calculation of end-diastolic and end-systolic mass and LV:RV free wall ratio. RV end-diastolic mass in normal subjects was 45 +/- 8 g, which was similar to the values determined in previously published postmortem studies, mean 46 g (range 23 to 68). The value determined in patients with dilated cardiomyopathy was higher (50 +/- 11 g), but this difference was not significant. LV:RV free wall ratio in cardiomyopathy (3.6 +/- 1.0) was greater than in normal subjects (2.4 +/- 0.3), because of the greater LV free wall mass in dilated cardiomyopathy, where LV free wall end-diastolic mass was 173 +/- 40 g vs 107.1 +/- 19.9 g in normal subjects (p less than 0.05). RV mass measurements had 6.4 +/- 3.6% interobserver and 7.3 +/- 6.1% intraobserver variability. There were no significant differences between end-diastolic and end-systolic mass measurements. Thus, cine magnetic resonance imaging can reproducibly calculate RV mass. The values in normal subjects correspond to previously reported postmortem values for a population without heart disease.

Adult↗