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Biomedical subjects

J E Juni

Publications and source records attributed to J E Juni.

64 records · Page 4Linked to original sources
PubMed1985

Scintigraphic characterization of amyloid cardiomyopathy.

Amyloidosis is an important entity in the differential diagnosis of cardiac failure of undetermined etiology. In this case report, the typical pattern of combined systolic and diastolic impairment in amyloid cardiomyopathy was demonstrated by analysis of the cardiac blood pool study. In addition, the patient described had mild uptake of Ga-67 citrate, as well as the characteristically intense myocardial uptake of Tc-99m pyrophosphate. Scintigraphic assessment may be particularly helpful when the diagnosis of amyloidosis is being considered in a patient with unexplained cardiac failure.

Aged↗
PubMed1985

Atlas of hepatic arterial perfusion scintigraphy.

Tc-99m MAA intra-arterial perfusion studies are necessary to determine blood flow distribution for hepatic arterial chemotherapy. In this mini-atlas, examples selected from over 900 cases to illustrate important points to aid in a better understanding and interpretation of these studies with particular emphasis on diagnostic and therapeutic interventions are presented.

Humans↗
PubMed1985

The use of a vasoconstrictor to improve tumour blood flow in intra-arterial chemotherapy: preliminary report.

The effectiveness of intra-arterial chemotherapy is dependent on a high tumour to normal blood flow ratio (T/NT). This report demonstrates the use of a vasoconstrictor (NE) to improve the relative blood flow to head and neck tumours by causing vasoconstriction and decreased blood flow to normal soft tissue. Five quantitative planar Tc-MAA perfusion studies were performed on three patients with increasing dose rates of norepinephrine (NE) to determine the optimal dose in each patient that would produce the best T/NT. All patients demonstrated a change in perfusion pattern with increasing dose rates (0.1 to 15 micrograms min-1), although there was considerable variation between patients. Quantitative SPECT was performed on two patients. In one, there was a 35% increase in the T/NT and a 16% decrease in arteriovenous (A-V) shunting to the lung.

Antineoplastic Agents↗
PubMed1985

The utility of SPECT for 99mTc-MAA hepatic arterial perfusion scintigraphy.

The utility of single-photon emission computed tomography (SPECT) for hepatic arterial perfusion scintigraphy was evaluated in 86 patients (91 studies). Previous reports have shown planar studies to be valuable for the clinical management of patients receiving intraarterial chemotherapy and more reliable than angiography in determining blood flow distribution. However, overlying areas of intra- and extrahepatic perfusion can sometimes make interpretation of these two-dimensional images difficult. Since SPECT has the potential to depict the three-dimensional distribution of perfusion, separate out overlying activity, and improve contrast resolution, SPECT Tc-MAA perfusion studies were compared to planar studies. Planar and SPECT studies both demonstrated the extent of hepatic and tumor perfusion, although occasionally SPECT added additional information. SPECT was most useful in confirming or excluding extrahepatic perfusion that was suspected but not definite on planar studies. Extrahepatic abdominal perfusion was found to be present in 11 (12%) of 91 studies. All patients with confirmed extrahepatic perfusion who received intraarterial chemotherapy had symptoms of drug toxicity compared to only a 23% incidence in those without evidence of extrahepatic perfusion (p less than 0.001). This report demonstrates that SPECT can improve the qualitative interpretation of hepatic arterial perfusion studies.

Adult↗
PubMed1984

Count-based left ventricular volume determination utilizing a left posterior oblique view for attenuation correction.

This study aimed to determine the inherent error of the left ventricular volume measurement from the gated equilibrium blood pool scintigram utilizing the count-based technique. The study population consisted of 26 patients who had undergone biplane contrast ventriculography. The patients were imaged with a parallel-hole collimator in the left anterior oblique position showing the septum to best advantage. A reference blood sample was counted and radionuclide volumes calculated without correction for attenuation. Attenuation corrected volumes were derived with the factor 1/e-mud, where d = distance from skin marker to center of the left ventricle in the orthogonal left posterior oblique view and mu = linear attenuation coefficient. A series of mu values from 0.08 to 0.15 cm-1 was evaluated. There was a trend toward improvement in the r value and lowering of the SEE with attenuation correction. The tightest 95% confidence limits achieved for an end-diastolic 150-ml ventricle were +/- 44 ml, and for an end-systolic 75-ml ventricle +/- 32 ml. In view of the magnitude of inherent error, the count-based volume measurement may be more suitable for group analyses and in cases in which an individual patient serves as his own control.

Adult↗
PubMedDate not supplied

Variations on calculating left-ventricular volume with the radionuclide count-based method.

Various methods for the calculation of left-ventricular volume by the count-based method utilizing red-blood-cell labeling with 99mTc and a parallel-hole collimator are evaluated. Attenuation correction, linked to an additional left posterior oblique view, is utilized for all 26 patients. We examine (1) two methods of calculating depth, (2) the use of a pair of attenuation coefficients, (3) the optimization of attenuation coefficients, and (4) the employment of an automated program for expansion of the region of interest. The standard error of the estimate (SEE) from the correlation of the radionuclide volumes with the contrast-angiography volumes, and the root-mean-square difference between the two volume sets at the minimum SEE are computed. It is found that optimizing a single linear attenuation coefficient assumed for attenuation correction best reduces the value of the SEE. The average of the optimum value from the end-diastolic data and that from the end-systolic data is 0.11 cm-1. This value agrees with the mean minus one standard deviation value determined independently from computed tomography scans (0.13-0.02 cm-1). It is also found that expansion of the region of interest beyond the second-derivative edge with an automated program, in order to correctly include more counts, does not lower the SEE as hoped. This result is in contrast to the results of others with different data and a manual method. Possible causes for the difference are given.

Aortic Valve Insufficiency↗
PubMedDate not supplied

Decreased exercise heart rate and blood pressure response in diabetic subjects with cardiac autonomic neuropathy.

Abnormal hemodynamic responses to exercise have been observed in diabetic subjects, but the pathogenesis and significance remain uncertain. We used maximal treadmill exercise to study 32 subjects with long-term insulin-dependent diabetes without clinical evidence of cardiac disease. Two of the 32 had occult ischemic heart disease revealed by stress electrocardiography and myocardial-perfusion scintigraphy and were excluded from subsequent analysis. In the remaining 30 subjects, we compared the responses to exercise of the 17 subjects with cardiac autonomic neuropathy diagnosed by noninvasive maneuvers (group 1) with the 13 without (group 2). At rest, the pressure-rate product (PRP) was higher in group 1 (114.0 +/- 5.7 vs. 95.9 +/- 5.3, P less than .05). With maximal exercise the increase in heart rate (44.6 +/- 4.8 vs. 79.0 +/- 5.4 beats/min, P less than .001), systolic blood pressure (36.8 +/- 5.9 vs. 55.0 +/- 5.8 mmHg, P = .02), and the PRP (102.0 +/- 7.3 vs. 182.0 +/- 8.2, P less than .001) were all lower in group 1 than in group 2, despite similar total treadmill times (631 +/- 47 vs. 587 +/- 40 s, P greater than .1). At each stage of exercise, the increase in heart rate and systolic blood pressure was lower in group 1 patients. The severity of cardiac autonomic neuropathy correlated inversely with the maximal increase in heart rate (r = -.68, P less than .001) and the PRP (r = -.58, P less than .005). Age, duration of diabetes, and the presence and severity of microvascular disease did not correlate with any of the hemodynamic parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗