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V Kalff

Publications and source records attributed to V Kalff.

At least 37 records · Page 2Linked to original sources
PubMed1991

Evidence for regional catecholamine uptake and storage sites in the transplanted human heart by positron emission tomography.

Positron emission tomography in combination with the newly introduced catecholamine analogue [11C]hydroxyephedrine ([11C]HED) enables the noninvasive delineation of sympathetic nerve terminals of the heart. To address the ongoing controversy over possible reinnervation of the human transplant, 5 healthy control subjects and 11 patients were studied after cardiac transplant by this imaging approach. Regional [11C]HED retention was compared to regional blood flow as assessed by rubidium-82. Transplant patients were divided into two groups. Group I had recent (less than 1 yr, 4.4 +/- 2.3 mo) surgery, while group II patients underwent cardiac transplantation more than 2 yr before imaging (3.5 +/- 1.3 yr). [11C]HED retention paralleled blood flow in normals, but was homogeneously reduced in group I. In contrast, group II patients revealed heterogeneous [11C]HED retention, with increased uptake in the proximal anterior and septal wall. Quantitative evaluation of [11C]HED retention revealed a 70% reduction in group I and 59% reduction in group II patients (P less than 0.001). In group II patients, [11C]HED retention reached 60% of normal in the proximal anterior wall. These data suggest the presence of neuronal tissue in the transplanted human heart, which may reflect regional sympathetic reinnervation.

Blood Pressure↗
PubMed1991

Hepatobiliary imaging.

Recent publications continue to refine the technique and interpretation of hepatobiliary scanning. Studies related to the evaluation of suspected acute cholecystitis have shown that morphine-augmented hepatobiliary imaging may not overcome the problem of false-positive study results in severely ill patients and the criterion for a normal study should be gallbladder visualization within 30 rather than 60 minutes. In patients with suspected acute cholecystitis, nonvisualized extrahepatic activity despite good hepatic uptake is highly predictive of acute cholecystitis, usually with biliary obstruction. The limitations of cholecystokinin-hepatobiliary imaging studies in patients with abdominal pain syndromes were defined and its use in evaluating common bile duct dynamics, and duodenogastric reflux was explored. Unusual findings and less-common uses of hepatobiliary scanning were reported, including assessment of conjoined twins, liver transplantation, primary biliary cirrhosis, gallbladder perforation, and persistent splenic visualization.

Biliary Tract↗
PubMed1990

111In-oxine labelled leukocyte scintigraphy in the detection and localization of active inflammation and sepsis.

We report an analysis of the results obtained in our first 100 studies with indium-111-oxine labelled leukocyte scintigraphy, a diagnostic technique which has recently become available for clinical evaluation within Australia. We used this technique to assess patients with suspected sepsis or inflammation after other commonly used investigations had failed to confirm a diagnosis. Four patient subgroups were evaluated: fever of unknown origin; suspected abdominal or postoperative sepsis; suspected active inflammatory bowel disease; and suspected sepsis or inflammation of bones or joints. The course of all patients was followed for at least three months to establish the accuracy of the technique. The leukocyte labelling procedure took 90 min and imaging was carried out typically 3-6, 24 and occasionally 48 h after reinjection of the labelled autologous leukocytes. In one patient labelling of leukocytes was unsuccessful. In the remaining 99 studies the overall sensitivity of leukocyte scintigraphy was 88% (36 of 41 patients with a proved inflammatory or infective disease focus had positive scan findings); and the specificity was 95% (55 of 58 cases with no proved disease focus had normal scan findings). This series supports the use of this method as the imaging procedure of choice in nuclear medicine for the evaluation of suspected acute sepsis (symptoms less than four weeks' duration), of inflammatory bowel disease and of suspected infections involving appendicular bones which contain no active bone marrow. It is also a useful secondary scintigraphic procedure, after gallium-67-citrate scintigraphy, in patients with suspected infective disorders of more than four weeks' duration.

Abdomen↗
PubMed1990

Association between false negative hepatobiliary scans and initial gallbladder visualization after 30 min.

We have reviewed the experience of our institution and the literature concerning the use of hepatobiliary scintigraphy for the diagnosis of acute cholecystitis. The aim of this study was to assess whether the hepatobiliary scintigraphic finding of initial gallbladder visualization within 30 min is a more reliable criterion for excluding acute cholecystitis than gallbladder visualization within 1 h after tracer injection. In our institution's consecutive series, 113 of 211 hepatobiliary studies had gallbladder visualization within 1 h. Gallbladder visualization time in this group had a log normal distribution, with gallbladder visualization occurring within 30 min in 107 of 113 (95%). Gallbladder visualization occurred between 31 and 60 min in only 6 (5%); nevertheless, our one false negative study came from this small subgroup of patient studies (P = 0.05). Review of the literature (1645 patients with iminodiacetic acid [99mTc-IDA] derivative studies) revealed 6 further timed false negative results with gallbladder visualization within 1 h. Of these studies, in 4 (67%) the gallbladder was visualized between 31 and 60 min and in only 2 before 30 min. One of these latter 2 patients had a rare anatomy. Analysis of the pooled institutional and literature data gave an estimated false negative rate of 21% if the gallbladder was visualized between 31 and 60 min. This was significantly higher (P less than 0.001) than the 0.5% false negative rate when the gallbladder was seen prior to 30 min, but similar to the false negative rate of 16% reported by Weissmann et al. for studies with initial visualization after 1 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1990

Noninvasive evaluation of sympathetic nervous system in human heart by positron emission tomography.

The noninvasive functional characterization of the cardiac sympathetic nervous system by imaging techniques may provide important pathophysiological information in various cardiac disease states. Hydroxyephedrine labeled with carbon 11 has been developed as a new catecholamine analogue to be used in the in vivo evaluation of presynaptic adrenergic nerve terminals by positron emission tomography (PET). To determine the feasibility of this imaging approach in the human heart, six normal volunteers and five patients with recent cardiac transplants underwent dynamic PET imaging after intravenous injection of 20 mCi [11C]hydroxyephedrine. Blood and myocardial tracer kinetics were assessed using a regions-of-interest approach. In normal volunteers, blood 11C activity cleared rapidly, whereas myocardium retained 11C activity with a long tissue half-life. Relative tracer retention in the myocardium averaged 79 +/- 31% of peak activity at 60 minutes after tracer injection. The heart-to-blood 11C activity ratio exceeded 6:1 as soon as 30 minutes after tracer injection, yielding excellent image quality. Little regional variation of tracer retention was observed, indicating homogeneous sympathetic innervation throughout the left ventricle. In the transplant recipients, myocardial [11C]hydroxyephedrine retention at 60 minutes was significantly less (-82%) than that of normal volunteers, indicating only little non-neuronal binding of the tracer in the denervated human heart. Thus, [11C]hydroxyephedrine, in combination with dynamic PET imaging, allows the noninvasive delineation of myocardial adrenergic nerve terminals. Tracer kinetic modeling may permit quantitative assessment of myocardial catecholamine uptake, which will in turn provide insights into the effects of various disease processes on the neuronal integrity of the heart.

Adult↗
PubMed1989

The radionuclide assessment of a system for slow intrathecal infusion of drugs.

The authors describe a new radionuclide method for assessing the functional integrity of slow intrathecal infusion devices. Approximately 11 mCi (400 MBq) of Tc-99m DTPA is injected into the pump chamber. Early and delayed imaging of the pump, tubing, and spinal cerebrospinal fluid space is performed on a digital large-field-of-view gamma camera. The digitally displayed images are then reviewed by adjustment of the grey scale window. Four patients have had eight studies and in each case the result has been confirmed by surgical exploration or by clinical response to change in therapy.

Aged↗
PubMed1988

Longitudinal study of ventricular function after the Mustard operation for transposition of the great arteries: a long term follow up.

An earlier study of 25 patients who were investigated by radionuclide angiography after a Mustard procedure showed that they had had evidence of right and left ventricular dysfunction at rest and with exercise. Twenty one (mean age 17.0 years (range 13.7-20.6) 11 female patients) of the original 25 patients were followed up a mean of 4.3 years later (mean 14.6 years (range 12.5-16.0) after the procedure). The group means for resting right and left ventricular ejection fraction and exercise response were not significantly different from those reported five years before. Individual changes in values were within the normal variation seen in serial studies. This long term longitudinal follow up of patients after the Mustard operation showed that although some patients still had right and left ventricular dysfunction, resting ventricular function and exercise response remained stable over a five year period. This preservation of cardiac function may contribute to the long term survival of patients after the Mustard procedure.

Adolescent↗
PubMed1986

Hepatobiliary scintigraphy. Increasing the accuracy of the preoperative diagnosis of acute cholecystitis.

The ability of hepatobiliary scintigraphy (HBS) to influence accurately the clinical diagnosis of acute cholecystitis was assessed prospectively in 70 consecutive patients with suspected acute cholecystitis. Before and after HBS, the referring surgeons completed a questionnaire on the probability of acute cholecystitis. Accuracy of diagnosis was assessed by clinical follow-up and chart review in all patients and by surgical and pathological evaluation in the 31 patients who underwent laparotomy. There were 27 patients with positive HBS results and 40 with negative HBS results; the results for three patients were indeterminate. None of the positive or negative HBS results were confirmed to be inaccurate. Negative results influenced diagnosis more often than did others. Results were negative in 13 patients whose assigned probability of acute cholecystitis was very high before HBS; in all 13 the assigned probability was very low after HBS, and in none of these patients was acute cholecystitis confirmed subsequently. These results support the use of hepatobiliary scintigraphy before proceeding to urgent cholecystectomy in patients with a clinical diagnosis of acute cholecystitis.

Acute Disease↗
PubMed1985

Radionuclide assessment of ventricular contraction at rest and during exercise following the Fontan procedure for either tricuspid atresia or single ventricle.

Ventricular contraction was evaluated in 18 patients studied at a mean of 2.6 years after Fontan repair. The diagnosis was tricuspid atresia in 9 patients and single ventricle in 9. Gated first-pass and gated equilibrium radionuclide ventriculography were performed at rest and during exercise. Abnormally low ventricular ejection fraction (EF) at rest was present in 8 of 18 patients by the gated equilibrium technique and 6 of 13 technically adequate gated first-pass studies. An abnormal response to exercise (failure of EF to increase less than or equal to 5% from rest to maximal exercise) was found in 10 of 16 patients by the gated equilibrium technique and in 8 of 12 by the gated first-pass technique. Only 2 patients by each radionuclide technique had both normal EF at rest and normal exercise response. Thus, this study confirms the frequent presence of abnormalities in ventricular contraction after the Fontan procedure at rest or during exercise or both despite absence of symptoms. Both EF response and the hemodynamic response during exercise were more abnormal in the presence of an atriopulmonary than an atrioventricular connection.

Adolescent↗
PubMed1985

Assessment of hemodynamic significance of isolated stenoses of the left anterior descending coronary artery using thallium-201 myocardial scintigraphy.

This study tests the hypothesis that the results of stress thallium-201 myocardial perfusion scans (TI-201) are related to the mean transstenotic pressure gradient of coronary stenoses independent of the percent luminal diameter narrowing seen at angiography. The 22 study patients (20 men, 2 women, mean age 47 years, range 30 to 62) had no previous myocardial infarction. Each underwent a symptom-limited, erect bicycle TI-201 test off antianginal therapy, shortly before percutaneous transluminal coronary angioplasty for isolated left anterior descending coronary artery stenosis. The percent narrowing, mean gradient at percutaneous transluminal coronary angioplasty and presence of a visually apparent TI-201 defect were independently evaluated and results compared. All 4 patients with 90% or greater diameter narrowing had positive TI-201 responses, and the mean gradient was 72 +/- 11 mm Hg. Among the 18 patients with less than 90% diameter narrowing, the mean gradient was higher (p less than 0.001) in the 11 with a positive TI-201 (63 +/- 15 mm Hg) than in the 7 with a negative TI-201 (33 +/- 20 mm Hg), but their percent narrowing did not differ significantly (72 +/- 14% vs 66 +/- 19%). Multiple regression analysis showed that the presence of a TI-201 defect was a strong (p = 0.003) and percent narrowing (p = 0.048) a weak independent predictor for gradient. When the mean gradient was normalized for the prestenotic pressure, both percent narrowing (p = 0.003) and TI-201 defects (p = 0.006) were significant independent predictors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Localization of exercise-induced myocardial ischemia with single view and biplanar radionuclide ventriculography: validation in single vessel coronary disease.

The ability of single view and biplanar radionuclide ventriculography (RVG) to determine the location of myocardial ischemia during maximal graded supine bicycle exercise was assessed in 50 patients with chest pain, no prior myocardial infarction, and a single coronary stenosis of greater than or equal to 50% luminal diameter narrowing at coronary angiography. A biplane collimator was used so that both right anterior oblique (RAO) gated first-pass and left anterior oblique (LAO) equilibrium RVG could be performed at rest and exercise. Results were compared with those obtained using 4-view 201Tl myocardial scintigraphy in the same patients. Regional wall motion abnormalities (WMA) and 201Tl perfusion defects were detected and assigned to individual coronary vessels by agreement between at least two of three independent observers, who read all studies blinded along with those from control subjects with chest pain but no angiographically significant coronary artery disease. When scintigraphic abnormalities were detected, both biplanar RVG (36/39 = 92%) and 201Tl (25/25 = 100%) were more frequently correct in predicting the stenosed vessel than single view LAO RVG (24/32 = 75%) (P less than 0.05). At RVG only inferior WMA, in the RAO view, predicted right coronary stenosis. Only posterolateral WMA, in the LAO view, predicted left circumflex stenosis. Thus biplanar, but not single view, LAO exercise RVG is a reasonable alternative to exercise 201Tl for localizing exercise-induced ischemic abnormalities to individual coronary stenoses.

Adult↗
PubMed1985

Value of combined assessment of global and segmental ventricular contraction with right anterior oblique ECG-gated first-pass and left anterior oblique equilibrium radionuclide ventriculography.

A semi-automated, variable-region-of-interest method of analysis was used to measure both global and segmental left ventricular (LV) and global right ventricular (RV) contraction with ECG-gated first-pass and equilibrium radionuclide ventriculography. Normal values were defined in 20 healthy volunteers, and in 24 symptomatic patients, the results were compared with right anterior oblique (RAO) contrast left ventriculography. The global LV ejection fraction (LVEF) obtained by equilibrium imaging in the left anterior oblique (LAO) projection correlated closely with the results obtained by the gated first-pass method in the RAO projection (r = 0.95) and those obtained with contrast left ventriculography (r = 0.94); furthermore, the interobserver variability was small (r = 0.985). The normal values for LVEF obtained using radionuclide techniques and contrast ventriculography did not differ, but with the equilibrium radionuclide method, the RV ejection fraction (RVEF) values were underestimated in comparison to those obtained by the RAO gated first-pass technique. In five patients with localised inferior segmental akinesis at contrast angiography, the RAO first-pass cine display demonstrated a corresponding wall-motion abnormality in all cases, but LAO equilibrium cine displays did so in only one out of five patients. For segmental quantitation of LV contraction, a computer programme defined the ventricular edge, divided the RAO LV images into five segments and determined both the segmental area contraction (SAC) and the counts-based segmental ejection fraction (SEF). Radionuclide SAC measurements correlated very strongly with SEF measurements (r = 0.94-0.99). Both radionuclide SAC and radionuclide SEF correlated well with contrast angiographic SAC, except in the inferobasal segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

omega-123I-hexadecanoic acid metabolic probe of cardiomyopathy.

The utility of omega-123I-hexadecanoic acid myocardial scintigraphy as a metabolic probe of cardiomyopathies was investigated. Sixteen patients with a variety of cardiomyopathies and myopathies that involve cardiac muscle and ten volunteers were imaged in the postabsorptive state in a 40 degrees LAO projection after a standard dose of omega-123I-hexadecanoic acid. An elimination T1/2 was calculated from the left ventricular myocardial time-activity curve. An uptake index, corrected for chest wall attenuation, was also computed in 7 of 10 volunteers and 8 of 16 patients. Of the 16 patients, only 2 had distinctly abnormal omega-123I-hexadecanoic acid myocardial tracer kinetics. The first patient had a metabolic disorder of which carnitine deficiency was one component. The second patient had endocardial fibroelastosis, a process which has been linked to disorders which deprive the myocardium of oxygen and energy. Therefore, the cardiomyopathy may have been caused by some abnormality of cardiac metabolism other than carnitine deficiency. Although of limited utility in the overall cardiomyopathic population, omega-123I-hexadecanoic acid myocardial scintigraphy should be further investigated as a screening test for carnitine deficiency and related metabolic abnormalities in patients at risk.

Adolescent↗
PubMed1985

Non-invasive assessment of pulmonary blood supply after staged repair of pulmonary atresia.

Radionuclide studies were performed to determine pulmonary blood flow in six children who had undergone surgery for pulmonary atresia, ventricular septal defect, and hypoplastic pulmonary arteries with or without major aortopulmonary collateral arteries. Lung blood flow was assessed from both particle perfusion lung scans and the pulmonary and systemic phase of a radionuclide dynamic flow study. Five patients had perfusion defects identified on the particle perfusion lung scan. In three of these, abnormal areas were perfused only during the systemic phase of the flow study, a combination of findings that indicate the presence of perfusion by collateral arteries. In one patient no systemic perfusion was noted and in one an initial particle perfusion study indicated the presence of a lung segment perfused by a collateral artery. In this last patient the particle perfusion scan after total correction showed a reduction in the size of the lung perfusion defect and no evidence of lung perfusion during the systemic phase of the flow study. The particle perfusion lung scan in the sixth patient showed pronounced asymmetry in blood flow to the lungs with no segmental perfusion defect on the particle perfusion scan and no abnormalities on the systemic flow study. It is concluded that radionuclide lung perfusion and flow studies provide useful information on lung perfusion and merit further evaluation to define their role in the management of these patients.

Abnormalities, Multiple↗
PubMed1984

Enalapril for severe congestive heart failure. A double-blind study.

The effects of the new, orally administered converting-enzyme inhibitor, enalapril (MK-421), were studied in 12 ambulatory patients with severe cardiac failure who were also receiving digoxin and diuretic agents. The study was double-blind, parallel, placebo-controlled and randomized. The clinical characteristics and pretreatment exercise performance were similar in the two groups of patients. All vasodilator drugs had been withdrawn two weeks before the start of the trial. At 12 weeks, the patients receiving enalapril showed a significant improvement in the functional class of the disease, exercise time (P less than 0.01), and maximum workload achieved, and experienced relief of symptoms. Blood pressure fell in patients receiving active treatment suggesting a reduction of afterload. Left ventricular ejection fraction was unchanged in enalapril-treated patients, but fell in patients on placebo (P less than 0.001). Enalapril was well tolerated without apparent adverse effects. It was effective when used with digoxin and diuretic agents in the treatment of severe cardiac failure, and its efficacy was maintained throughout 12 weeks of therapy.

Administration, Oral↗