Drug-induced changes in the radiographic appearance of the heart.
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Cardiomyopathies↗
Biomedical subjects
L M Boxt
Publications and source records attributed to L M Boxt.
Estimation of pulmonary artery pressure in patients with primary pulmonary hypertension by quantitative analysis of magnetic resonance images.
The use of magnetic resonance (MR) images for estimating mean pulmonary artery pressure (PAP) was tested by comparing main pulmonary artery (MPA) and middescending thoracic aorta (AO) caliber in 12 patients with primary pulmonary hypertension (PPH) with measurements made in eight other patients who were observed for diseases other than heart disease (controls). The ratio MPA/AO and the ratios of vessel caliber normalized to body surface area (MPAI and AOI, respectively) were computed. The PAP was obtained in all PPH patients and compared with caliber measurements. The PPH MPA (3.6 +/- 0.8 cm) was significantly larger than the control MPA (2.9 +/- 0.3 cm, p = 0.02); the PPH MPAI (2.8 +/- 0.7 cm/M2) was significantly greater than the control MPA (1.7 +/- 0.2 cm/M2, p < 0.0001). Control AO (2.2 +/- 0.3 cm) was significantly greater than PPH AO (1.6 +/- 0.4 cm, p < 0.0001); there was no significant difference between control AOI (1.3 +/- 0.2 cm/M2) and PPH AOI (1.2 +/- 0.2 cm/M2, p = 0.25). The PPH MPA/AO (2.3 +/- 0.6) was significantly greater than the control MPA/AO (1.3 +/- 0.1, p < 0.0001); overlap between MPA in the two groups was eliminated by indexing values to AO caliber (MPA/AO). Among PPH patients there was strong correlation between PAP and MPA/AO (PAP = 24 x MPA/AO + 3.7, r = 0.7, p < 0.01). Increased MPA/AO denotes the presence of pulmonary hypertension and may be used to estimate PAP.
Adult↗
Normal plain film examination of the heart and great arteries in the adult.
A plain film chest examination is nearly always obtained in the management of patients suspected of cardiac disease. The wealth of diagnostic information obtained from posteroanterior and lateral thoracic images is often essential data needed to direct the evaluation and treatment of these patients. Appreciation of the normal cardiac, pulmonary, and great vessel anatomy provides a basis for the identification and characterization of the abnormal. Furthermore, the chest radiograph provides an important means to appreciate the pathophysiologic mechanisms underlying the morphologic changes in patients with congenital heart disease.
Adult↗
Fractal analysis of pulmonary arteries: the fractal dimension is lower in pulmonary hypertension.
We analyzed the spatial structure of contact radiographs of barium-filled pulmonary arteries of rats raised in room air and in two environments that induce pulmonary arterial hypertension (PAH)--hypoxia and hyperoxia. We found that the spatial structure of the pulmonary arteries was fractal in both the control and the hypertensive lungs. The fractal dimension of the pulmonary arteries of the control lungs was 1.62 +/- 0.01 (mean +/- SEM), which is greater than that of both the hypoxic lungs 1.50 +/- 0.03 (p < 0.01) and the hyperoxic lungs 1.44 +/- 0.01 (p < 0.01). There was no significant difference between the hypoxic and hyperoxic lungs. The fractal dimension may be a useful clinical index to quantify pathologic changes in the pulmonary arterial tree.
Animals↗
Introduction to coronary arteriography.
Coronary arteriography is the most reliable means of investigating and quantitating the severity of coronary artery occlusive disease. Although the procedure is no longer performed exclusively by radiologists, their input into its interpretation is valued. Furthermore, current and future advances in nonangiographic means of demonstrating coronary artery morphology, including magnetic resonance angiography, reinforce the need for radiologists to remain familiar with techniques for the performance of coronary arteriography, the basic anatomy of the coronary artery tree, and patterns of congenital and acquired coronary artery disease.
Cardiac Catheterization↗
Angiocardiography in the diagnosis of congenital heart disease.
Despite tremendous advances in cardiac imaging technology, there still exists an important role for the performance of angiocardiography in children with congenital heart disease. This article contains an outline describing the facilities in which the examinations are performed, how the examination is performed, and, most importantly, the basic tenets of interpretation.
Age Factors↗
Estimation of myocardial water content using transverse relaxation time from dual spin-echo magnetic resonance imaging.
Dual spin-echo magnetic resonance imaging may be used for calculation of transverse myocardial relaxation time from the signal intensity of the echoes considered. In this study, the ability of myocardial transverse relaxation time (T2) to quantitate myocardial edema of the right ventricle (RV) and left ventricle (LV) was tested. Dual spin-echo magnetic resonance images of the entire hearts were obtained and T2 of the RV and LV myocardium calculated from the signal intensities within multiple regions of interest distributed over the myocardium. Six hearts were intermittently perfused through an aortic cannula with three perfusates of decreasing osmolality. Biopsies were obtained for water content (WC) analysis both before and after imaging the hearts at baseline and post-perfusion. A seventh (control) heart was not perfused; instead dual spin-echo imaging was performed at the same time intervals as in the perfused hearts. Prior to any intervention, there was no significant difference between baseline RV (79.49 +/- 2.10%) and LV (77.99 +/- 2.44%, p = .2) myocardial water content; RV myocardial T2 (59.9 +/- 5.8 msec) was slightly but not significantly longer than that of the LV (54.6 +/- 5.7 msec, p = .1). After induction of edema, strong correlation was found between right ventricular myocardial water content measurements and right ventricular T2 (RV WC = 68.5 + 0.19 x RV T2; N = 27, R = 0.92, p < .0001, SEE = 1.56%). Similarly, strong correlation was found between left ventricular myocardial water content and T2 (LV WC = 62.1 + 0.29 x LV T2; N = 27, R = 0.92, p < .0001, SEE = 1.80%).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Estimation of right ventricular mass in normal subjects and in patients with primary pulmonary hypertension by nuclear magnetic resonance imaging.
OBJECTIVES: This study was designed to test the accuracy of nuclear magnetic resonance (NMR) imaging as a noninvasive technique for estimating right ventricular mass in normal subjects and in patients with primary pulmonary hypertension. BACKGROUND: An accurate means of noninvasively estimating right ventricular mass may allow better characterization of the degree of right-sided pressure or volume overload caused by underlying cardiac or pulmonary diseases. METHODS: End-diastolic short-axis electrocardiogram (ECG)-gated spin echo NMR images of the heart were obtained in vivo in 13 patients with primary pulmonary hypertension and 10 normal adult volunteers. Both right and left ventricular mass were computed by summing the myocardial slice volumes over all slices spanning the myocardium and multiplying by myocardial density. This technique of myocardial mass determination was verified by imaging 10 calf hearts and comparing the NMR-determined right and left myocardial mass with the actual mass determined by weighing the right and left ventricles. RESULTS: In the calf heart study, an excellent correlation was obtained between the directly measured ventricular mass and the NMR-calculated mass, for both the right and the left ventricle. Patients with primary pulmonary hypertension had an elevated right ventricular mass index compared with that of normal subjects (62.69 +/- 8.72 g/m2 vs. 23.32 +/- 1.36 g/m2, p < 0.0005). There was no significant difference in left ventricular mass index between the two groups. Both mean intraobserver and inter-observer variability in myocardial mass determination were low. Linear regression analysis between right ventricular mass index and mean pulmonary artery pressure was significant (r = 0.75, p < 0.003). CONCLUSIONS: Electrocardiogram-gated spin echo NMR imaging of the heart may be used for quantitating right ventricular mass in normal subjects and in patients with primary pulmonary hypertension, in whom it may also provide an alternative noninvasive technique for estimating mean pulmonary artery pressure.
Adolescent↗
Cardiac radiology. A survey of its current status.
RATIONALE AND OBJECTIVES: A number of pressures have taken their toll on cardiovascular (CV) imaging in radiology. We conducted a survey to develop accurate information about the current status of cardiac radiology (CR) that might guide future responses and initiatives. METHODS: To assess the current status of CR, a survey form was sent to all 117 active radiologist members of the North American Society for Cardiac Imaging (N = 72) and/or the Council on Cardiovascular Radiology of the American Heart Association (N = 98). The topics of inquiry included 1) present CR staffing; 2) specific adult and pediatric CR activities (cardiac plain-film interpretation, cardio-angiography (CA), echocardiography, nuclear cardiology (NC), and CV magnetic resonance imaging (MRI); 3) CR instruction of radiology residents; and 4) CR fellowship activities. RESULTS: The survey was concluded with 64 (55%) individual responses from 58 (67%) different centers with CR groups. An overall need for CR staff (average unfilled positions/center = 0.4) was indicated. Regarding CR activities, the following were reported: 1) universal cardiac plain-film interpretation by radiologists, with most CR groups involved (adult, 64%; pediatric, 64%); 2) moderate CR contributions to CA (adult, 62%; pediatric, 57%), of which cine interpretation was the most common form (79% and 85%, respectively); 3) rare CR involvement in echocardiography (adult, 9%; pediatric, 6%); 4) low-level CR involvement in NC (adult, 16%; pediatric, 17%), but high level when combined with that of nuclear medicine (93% and 91%, respectively); and 5) almost universal radiology responsibility for CV MRI (adult, 96%; pediatric, 96%), with extensive CR involvement (77% and 82%, respectively). Of 46 reporting academic centers, most (76%) required CR training of residents; a smaller proportion (33%) of all centers offered CR fellowships. CONCLUSIONS: Because of the insights gained from this survey, recommendations can be better made to strengthen CR based on a foundation in plain-film interpretation, computed tomography, NC, and MRI.
Adult↗
Cardiac radiology. An asset to radiology?
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Cardiovascular System↗
Magnetic resonance imaging for quantitation of right ventricular volume in patients with pulmonary hypertension.
Evaluation of right ventricular function in patients with right-sided heart failure is difficult because of the complex anatomy of the right ventricle; the distinct geometry of the dilating, failing right ventricle; its variance from the typical oblate spheroid shape used to model the left ventricle; associated cardiac lesions in patients with right ventricular failure (including tricuspid and pulmonary regurgitation); and the inherent risk of conventional contrast ventriculography. With magnetic resonance techniques, tomographic images of the heart may be obtained at multiple points in the cardiac cycle without the use of intravascular contrast agents. From the end-diastolic and end-systolic images, chamber volume may then be determined directly without any modeling assumptions as to the geometry of the ventricular chamber.
Cardiac Volume↗
Direct quantitation of right and left ventricular volumes with nuclear magnetic resonance imaging in patients with primary pulmonary hypertension.
To test the utility of electrocardiographically gated spin echo nuclear magnetic resonance (NMR) imaging in quantitating right and left ventricular volumes and function in patients with primary pulmonary hypertension, right and left ventricular end-diastolic and end-systolic volumes, stroke volumes and ejection fractions were determined in 11 patients with primary pulmonary hypertension and in 10 subjects with normal echocardiographic findings. Ventricular chamber volumes were computed by summing the ventricular chamber volumes of each NMR slice at end-diastole and end-systole. This technique was verified by comparison of results obtained by this method and with the water displacement volumes of eight water-filled latex balloons and ventricular casts of eight excised bovine hearts. In the patients with primary pulmonary hypertension, right ventricular volume indexes were 121 +/- 45 ml/m2 at end-diastole and 70.1 +/- 41.6 ml/m2 at end-systole; both values were significantly greater than values in the normal subjects (67.9 +/- 13.4 and 27.9 +/- 7.5 ml/m2, respectively). Left ventricular end-diastolic volume index was significantly less in the patients (44.9 +/- 9.7 ml/m2) than in the normal subjects (68.9 +/- 13.1 ml/m2). There was no significant difference in left ventricular end-systolic volume between the two groups (24.4 +/- 8.6 and 27.1 +/- 7.8 ml/m2, respectively). Right and left ventricular ejection fractions in the patients with primary pulmonary hypertension (0.43 +/- 0.21 and 0.46 +/- 0.15, respectively) were significantly less than values in normal subjects (0.59 +/- 0.09 and 0.6 +/- 0.11, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Effects of drugs on the radiographic appearance of the heart.
Despite the exposure of the general population to a wide variety of exogenous environmental toxins, a growing armamentarium of potent medications, and an array of licit and illicit drugs, relatively little evidence of related pathophysiologic effects is seen on the radiographic appearance of the heart. When radiographic changes are manifested, however, specific alterations are observed in the contour of the cardiac silhouette. Generalized enlargement of the cardiac silhouette may be secondary to development of dilated cardiomyopathy or the accumulation of pericardial fluid. Localized changes in the contour of specific portions of the cardiac silhouette may be the result of ventricular hypertrophy or valvular stenosis or regurgitation. This article describes the cardiac radiographic findings resulting from the use of specific substances and discusses possible mechanisms that ultimately result in these changes. Identification and characterization of these morphologic changes may be helpful in the clinical management of patients.
Cardiomegaly↗
Motion dependence of myocardial transverse relaxation time in magnetic resonance imaging.
We discuss the effects of motion on the computation of the myocardial transverse relaxation time by use of magnetic resonance imaging. Equations describing its behavior are derived and illustrated graphically under different conditions. It is shown that the myocardial transverse relaxation time calculated from magnetic resonance images depends on the actual myocardial transverse relaxation time ex vivo (T2) as well as the phase of the cardiac cycle in which it is computed, heart rate, cardiac wall velocity, choice of spin-echoes used in the calculation, and the spin-echo times employed. In particular, the error in T2 decreases when both the first and third echoes are employed in the calculation, rather than only the first two echoes. However, the myocardial transverse relaxation time is more strongly dependent on heart rate in the former case rather than in the latter. Furthermore, the error in T2, when both the first and second spin echoes are used in the calculation, is seen to increase as the spin-echo time shortens. On the other hand, the error in T2 decreases for shorter spin-echo times when both the first and third spin echoes are used instead. The results are relevant to the noninvasive assessment of ischemia, cardiac transplantation rejection, and other myocardial disorders.
Heart↗
The effects of various indwelling ureteral catheter materials on the normal canine ureter.
In an attempt to objectively evaluate the biocompatibility of materials commonly used for ureteral stenting, stent-catheters made of four different materials were placed randomly in 31 ureters of 19 mongrel dogs. Animals underwent urography at four weeks and were sacrificed at six weeks. Mild hydronephrosis was noted in eight instances, essentially unrelated to specific material. Silicone, C-flex and polyurethane stents caused a similar, mild degree of ureteral edema, but ureters stented with Silitek demonstrated fairly marked edema. Epithelial ulceration and erosion, often severe, occurred with all polyurethane stents, and rarely with the three other materials. All materials differed statistically from controls, and C-flex caused less reaction overall than polyurethane, indicating differences in biocompatibility of the various materials which may be relevant to their use in patients undergoing long-term ureteral stenting. In practical terms, these suggest that certain materials, notably silicone and C-flex, are more suitable for ureteral stenting than others.
Animals↗
Use of digital video coronary arteriography in the performance of percutaneous transluminal coronary angioplasty.
Digital video coronary arteriography (DVCA) was used in 59 cases of percutaneous transluminal coronary angioplasty (PTCA) and found to be useful for display of imagery to facilitate choice of approach to a stenotic lesion; providing a "road map," simplifying guide wire manipulation and selective catheterization of vessels during PTCA; and archival of pre- and post-PTCA images. Use of DVCA for real-time display inside the catheterization laboratory expedites the successful performance of PTCA and is a convenient means of image archival.
Adult↗
Partial splenic embolization for painful splenomegaly.
Therapeutic splenic embolization has been commonly performed for hypersplenism, tumor palliation, and other indications, but has not been reported as a therapy specifically for pain relief. We describe 1 patient with chronic pain secondary to severe splenomegaly in whom surgery was contraindicated. Selective partial splenic embolization achieved a pain-free state for the patient without significant complications.
Adult↗
Nuclear magnetic resonance spectroscopy of rat ventricles following supravalvar aortic banding. A model of left ventricular hypertrophy.
Left ventricular hypertrophy produced by supravalvar aortic banding in infant rats was studied by proton magnetic resonance spectroscopy. Weight gain at 11 weeks of age in the 11 male Sprague-Dawley rats with aortic bands placed at three weeks was similar to that of the 14 controls. The left ventricle of banded rats hypertrophied, increasing the ratio of left ventricle plus septum to body weight (LV + S/BW) by more than 50% (P less than .00001). Right ventricular weight (RV/BW) increased slightly (P less than .03). T1 and T2 relaxation times of LV + S, RV, and thigh muscle (Th) from the banded and control rats were compared. The T2 value distinguished hypertrophied from control LV + S (P less than .003), but not between RV or Th from the two groups. For banded rats only, the T2 value distinguished each muscle type: LV + S from RV, LV + S from Th, and RV from Th (P less than .00001 for each). For control rats, cardiac muscle was distinguished from Th (P less than .00001), but LV + S and RV were similar. The T1 value did not distinguish either the banded from the control group or any of the muscle types. Percent water content was similar for all tissues. Any correlation between water content and T1 or T2 was inconsistent or weak.
Animals↗