The lack of a reliable quantitative description of blood flow in man has hampered the development of accurate biokinetic models of essential elements, drugs, imaging agents, and carcinogens. In this paper we review and analyse data on blood flow and identify representative percentages of cardiac output and absolute blood flow rates to organs and tissues of man for use as reference values for biokinetic models. To keep the review and analysis to a manageable size we have limited attention to the resting state and have suggested reference values for absolute and relative flow rates only for adult males and females.

https://iopscience.iop.org/article/10.1088/0143-0815/10/3/001/pdf

Reference values for resting blood flow to organs of man.

Atrial fibrillation in hypertrophic cardiomyopathy: a longitudinal study.

To investigate the incidence of abnormal exercise blood pressure responses in hypertrophic cardiomyopathy (HCM) and the potential role of hemodynamic instability as a mechanism of sudden death, 129 consecutive patients with HCM underwent maximal symptom-limited treadmill exercise testing with blood pressure recording. Four patterns of blood pressure response were observed. Forty-three patients had significant exercise hypotension, with either a continuous fall in systolic blood pressure (n = 5) from the start of exercise or a sudden fall in systolic blood pressure (20-100 mm Hg; mean, 40 mm Hg) from the peak value (n = 38), 23 patients had a normal response during exercise but an abnormal blood pressure response in the recovery period, and the remaining 62 patients demonstrated a normal blood pressure response. Patients with exercise hypotension were younger (33 +/- 14 versus 46 +/- 14 years) and more of them had a family history of HCM and sudden death compared with those with a normal blood pressure response (15 of 43 versus 6 of 62 patients). Similarly, the 23 patients with abnormal recovery blood pressure responses were younger (43 +/- 16 versus 46 +/- 14 years) and had a higher incidence of a family history of sudden death (10 of 24 versus 6 of 62 patients). Left ventricular cavity dimensions were smaller in those with exercise hypotension, but 11 other clinical, echocardiographic, and arrhythmic variables were similar. To assess the mechanism of exercise hypotension, 14 patients who demonstrated exercise hypotension and 14 symptomatic patients with a normal exercise blood pressure response underwent invasive hemodynamic exercise testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormal blood pressure response during exercise in hypertrophic cardiomyopathy.

Attenuation correction in single-photon (SPET) and positron emission (PET) tomography is now accepted as a vital component for the production of artefact-free, quantitative data. The most accurate attenuation correction methods are based on measured transmission scans acquired before, during, or after the emission scan. Alternative methods use segmented images, assumed attenuation coefficients or consistency criteria to compensate for photon attenuation in reconstructed images. This review examines the methods of acquiring transmission scans in both SPET and PET and the manner in which these data are used. While attenuation correction gives an exact correction in PET, as opposed to an approximate one in SPET, the magnitude of the correction factors required in PET is far greater than in SPET. Transmission scans also have a number of other potential applications in emission tomography apart from attenuation correction, such as scatter correction, inter-study spatial co-registration and alignment, and motion detection and correction. The ability to acquire high-quality transmission data in a practical clinical protocol is now an essential part of the practice of nuclear medicine.

Transmission scanning in emission tomography

Twenty-four patients with persistent epithelial ovarian cancer after chemotherapy with or without external beam irradiation, were treated with intraperitoneally administered 131I-labeled monoclonal antibodies HMFG1, HMFG2, AUA1, H17E2, directed against tumor-associated antigens. Acute side effects were mild abdominal pain, pyrexia, diarrhea, and moderate reversible pancytopenia. One patient developed a subphrenic abscess requiring surgical drainage. Eight patients with large volume disease, ie, greater than 2 cm tumor diameter, did not respond to antibody-guided irradiation and died of progressive disease within 9 months of treatment. Sixteen patients had small-volume (less than 2 cm) disease at the time of treatment with radiolabeled antibody. Seven patients failed to respond, and of nine initial responders, four patients remain alive and free from disease 6 months to 3 years from treatment. Analysis of the data on relapse indicated that doses greater than 140 mCi were more effective than lower doses. We...

Antibody-guided irradiation of advanced ovarian cancer with intraperitoneally administered radiolabeled monoclonal antibodies.

A simplified method of absolute quantitation of activity in any region of the body is presented utilizing a series of views acquired with a scintillation camera linked to a computer. An accuracy of ±6% may be achieved. No additional programming needs to be added to the standard nuclear medicine computer software and a knowledge of the attenuation coefficients involved and the shape or position of the organs examined is not presupposed or estimated. Attenuation correction is performed using a transmission image as one of the sequence of camera views. The phantom measurements used to evaluate the technique are decsribed and some clinical results presented.

A simplified method of quantitating organ uptake using a gamma camera

Left ventricular (LV) function at rest was assessed by radionuclide angiography in 30 patients with hypertrophic cardiomyopathy (HC) before and during treatment with amiodarone (600 to 800 mg for 1 week, 200 to 400 mg/day thereafter) for an initial maintenance period of 1 month in 30 patients and 6 months in 12 patients The reproducibility of the measurements was assessed by performing control studies within 24 hours in 13 patients and at 1 to 6 months in 6 patients, and 95% confidence limits for spontaneous change were determined There was a significant decrease in heart rate at 1 month (from 67 ± 9 vs 61 ± 9 beats/min, p

Effect of amiodarone on left-ventricular ejection and filling in hypertrophic cardiomyopathy as assessed by radionuclide angiography

A method for imaging the right side of the heart (atrium, ventricle and main pulmonary artery) and for assessment of RV systolic function (ejection fraction and ejection rate) is described. An ultra-short-lived isotope (81Krm) is continuously eluted in 5% dextrose and infused into an ante-cubital arm vein; standard multigated images are acquired using a gamma camera and commercially available software. Preliminary evaluation of the method in 55 subjects (20 with repaired tetralogy of Fallot, 14 with dilated cardiomyopathy and 21 normal volunteers) showed that the technical success rate was 100%; that RV boundaries free from LV overlap can be clearly visualised due to efficient exhalation of 81Krm through the lungs and that 81Krm measurements of RVEF are reproducible. The technique offers considerable potential for serial non-invasive assessment of RV function.

Assessment of right ventricular function and anatomy using peripheral vein infusion of krypton 81m

To evaluate the prognostic significance of diastolic function in hypertrophic cardiomyopathy (HC), technetium-99m gated equilibrium radionuclide angiography, acquired in list mode, was performed in 161 patients. Five diastolic indexes were calculated. During 3.0 ± 1.9 years, 13 patients had disease-related deaths. With univariate analysis, these patients were younger (29 ± 20 vs 42 ± 16 years; p

Prognostic significance of radionuclide-assessed diastolic function in hypertrophic cardiomyopathy

Ventilation perfusion imaging using single photon emission tomography was carried out in the supine position on four subjects, three normal volunteers and one patient, all free from evidence of respiratory disease. Ventilation imaging was by means of the steady-state inhalation of krypton 8lm, perfusion imaging utilised technetium 99m labelled macroaggregates. In the three normal volunteers, perfusion studies were repeated using steady state infusion of 81Krm in solution. Ventilation perfusion ratios were calculated for the anterior, middle and posterior regions of the lung using axial slices from apex to base. The results using 99Tcm for perfusion showed a gradient of ventilation perfusion ratios from front to back of 1.27 anteriorly and 0.93 posteriorly for the right lung, 1.06 anteriorly and 0.77 posteriorly for the left lung. Using 81Krm for perfusion a small gradient of 0.94 to 0.82 was observed.

Melvyn J. Myers

Papers

A simplified method of quantitating organ uptake using a gamma camera

Effect of amiodarone on left-ventricular ejection and filling in hypertrophic cardiomyopathy as assessed by radionuclide angiography

Assessment of right ventricular function and anatomy using peripheral vein infusion of krypton 81m

Prognostic significance of radionuclide-assessed diastolic function in hypertrophic cardiomyopathy

Ventilation perfusion ratios of the normal supine lung using emission tomography