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Biomedical subjects

V Kalff

Publications and source records attributed to V Kalff.

At least 55 records · Page 3Linked to original sources
PubMed1984

Scintigraphic localization of a recurrent phaeochromocytoma by means of iodine-131 metaiodobenzylguanidine.

A new adrenomedullary scintigraphic imaging agent, iodine-131-labelled metaiodobenzylguanidine (MIBG), was used to localize a recurrent phaeochromocytoma in a 27-year-old man in whom the site of tumour could not be determined by any other means. MIBG scintigraphy is easy to perform and is highly specific for functioning aberrant adrenomedullary tissue. It complements other methods for localization of phaeochromocytoma and, under some circumstances, it may become the initial imaging procedure of choice in the screening of patients in whom the biochemical or clinical evidence suggests the presence of such tumours.

3-Iodobenzylguanidine↗
PubMed1984

Bilateral pheochromocytomas.

Bilateral pheochromocytomas most often occur as components of well-described syndromes: multiple endocrine neoplasia types 2a and 2b, von Hippel-Lindau disease and neurofibromatosis. We describe 4 patients with isolated bilateral pheochromocytomas; their tumors arose in the absence of stigmata and family history of the syndromes. The manifestations of these 4 individuals are compared with those of 14 other patients who developed pheochromocytomas in both adrenal glands as part of the syndromes. The 4 patients with the isolated pheochromocytomas manifest more rapidly progressing disease: they were 10-14 yrs of age, distinctly younger than those with the syndrome. Three of the 4 exhibited adrenal medullas that were composed entirely of tumor in contrast to the hyperplasia that usually accompanies other bilateral pheochromocytomas. However, malignant transformation of pheochromocytomas was seen both in a non-syndrome patient and in a patient with Lindau's disease.

Adolescent↗
PubMed1984

The effect of dobutamine on exercise performance in patients with symptomatic ischemic heart disease.

The effect of dobutamine on exercise performance was assessed in 20 patients with ischemic heart disease (CAD) and a positive stress test. These patients had a wide range of resting left ventricular ejection fraction (range 22% to 69%, mean 42%). Each patient entered a double-blind crossover study in which two identical exercise radionuclide ventriculograms were performed in patients on dobutamine, 5 micrograms/kg/min intravenously, or placebo. Dobutamine increased resting left ventricular ejection fraction. Although ejection fraction fell with dobutamine during submaximal exercise, it remained higher than with placebo. At peak exercise, ejection fraction fell to the same level on dobutamine as with placebo. Dobutamine diminished exercise time and time to ischemia while peak pressure-rate product was unchanged. Four of 20 patients developed complex ventricular premature beats, all while on dobutamine. Although useful when administered to resting patients with acute left ventricular failure, dobutamine's effects may be deleterious in exercising patients with chronic ischemic heart disease.

Adult↗
PubMed1984

Right and left ventricular function at rest and with exercise after the Mustard operation for transposition of the great arteries.

Right and left ventricular function was assessed in 25 children (mean age at study 12.2 years and at operation 2.6 years) after a Mustard repair for transposition of the great arteries. Gated first pass and gated equilibrium radionuclide ventriculography was performed on all patients at rest and during supine bicycle exercise. The mean right ventricular ejection fraction did not increase with exercise by either technique. Individual results for right ventricular ejection fraction showed that with the gated equilibrium technique 71% had an abnormal exercise response (normal response being an increase in ejection fraction greater than 5%) and with the gated first pass technique 61% had abnormal results. Although the mean left ventricular ejection fraction increased significantly with exercise, 35% of patients had an abnormal exercise response with the equilibrium technique and 41% with the first pass technique. There was no evidence of a predictive relation between ventricular function and any clinical or haemodynamic variable examined. Covert right and left ventricular dysfunction can frequently be detected by exercise radionuclide ventriculography in long term survivors of repair for transposition of the great arteries. The prognostic consequences of these findings are unclear at present.

Adolescent↗
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↗
PubMed1984

Liver-spleen studies with the rotating gamma camera. I: Utility of the rotating display.

The clinical utility of a computer-generated dynamic cine display (rotating display) of the unprocessed projection images of the liver and spleen obtained with rotating gamma-camera tomography was prospectively compared with that of the standard multi-view static scintigram display. Two hundred cases were independently and blindly analyzed by three observers. Each study was coded from 1-5, indicating the certainty of normality or abnormality present. When abnormality was noted, the study was assessed for the presence of metastatic disease, inhomogeneous uptake, hepatosplenomegaly, and colloid distribution shift. ROC analysis was then performed on the initial coding for certainty of abnormality, and the causes for discrepancies were evaluated from the assessment of the type of abnormality present. No significant interdisplay differences could be demonstrated. In the small percentage of cases where interdisplay disagreement occurred, this was usually accompanied by marked interobserver variation and was most commonly due to differing assessment of organ size. It is concluded that the static and rotating display formats can be used interchangeably in the evaluation of technetium-99m-labeled sulfur colloid liver studies.

Data Display↗
PubMed1984

Liver-spleen studies with the rotating gamma camera. II: Utility of tomography.

A prospective comparison of conventional scintigrams and single-photon emission computed tomography (SPECT) studies of the liver and spleen was carried out. Care was taken to insure high-quality, artifact-free studies. Two hundred patients were imaged by both methods. A definitive diagnosis of normal was established in 86 cases, abnormal in 107 cases, and seven cases were indeterminate. All studies were read by two observers and graded as to degree and type of abnormality seen. ROC curves were constructed and errors of interpretation studied to identify problems. One observer showed no difference in performance between the two methods. The other showed a small improvement with SPECT. Image artifacts apparently contributed to errors of interpretation in 24 of 54 cases using SPECT. SPECT appears comparable with conventional scintigraphy and may improve specificity. Improvements are needed in SPECT imaging equipment and image display capability to realize fully the potential of SPECT.

Humans↗
PubMed1984

An immunohistochemical study of pheochromocytomas.

Twenty -six adrenal pheochromocytomas and four normal adrenal medullae were studied immunohistochemically. These included four malignant tumors with proven metastases, six tumors in patients with neurofibromatosis, nine tumors in patients with multiple endocrine neoplasia type 2, and seven sporadic nonfamilial pheochromocytomas. Immunohistochemical localization of neuron-specific enolase (NSE) was seen in all tumors and in the four normal adrenals. Methionine enkephalin-like immunoreactivity was present in tumors from all four groups and in the normal adrenals. Corticotropinlike immunoreactivity was found focally in two normal adrenal medullae and in four benign pheochromocytomas. Our results indicated that NSE was present in all four major groups of pheochromocytomas, including benign and malignant tumors. This marker aided in distinguishing between adrenal cortical and medullary tumors in unusually difficult cases, since all normal adrenal cortex and adrenal cortical tumors had negative test results for NSE.

14-3-3 Proteins↗
PubMed1984

The location of middle mediastinal pheochromocytomas.

Eight middle mediastinal pheochromocytomas were located by means of 131I- meta- iodobenzylguanidine scintigraphy. The exact anatomic location of the lesions was confirmed by means of dynamic computed tomographic scanning following bolus injection of contrast medium. In all but one case the lesion had not been detected prior to scintigraphy despite extensive investigations including arteriography, venography with sampling, computed tomography with infusion of contrast medium, and in some cases surgical exploration of the abdomen and chest. Accurate anatomic location of the lesion permitted resection of five lesions from the cardiac atria and one from the aortopulmonary window. A sixth case in which an atrial pheochromocytoma was found by coronary angiography was not cured by resection of the primary tumor, and 131I- meta- iodobenzylguanidine scintigraphy revealed extensive metastases. Thus 131I- meta- iodobenzylguanidine scintigraphy has been of considerable value in the location of pheochromocytomas of the middle mediastinum, which may be a more frequent site than previously recognized.

3-Iodobenzylguanidine↗
PubMed1983

Incremental value of clinical assessment, supine exercise electrocardiography, and biplane exercise radionuclide ventriculography in the prediction of coronary artery disease in men with chest pain.

The incremental value of clinical assessment, exercise electrocardiography (ECG) and biplane radionuclide ventriculography (RVG) in the prediction of coronary artery disease (CAD) was assessed in 105 men without myocardial infarction who were undergoing coronary angiography for investigation of chest pain. Independent clinical assessment of chest pain was made prospectively by 2 physicians. Graded supine bicycle exercise testing was symptom-limited. Right anterior oblique ECG-gated first-pass RVG and left anterior oblique ECG-gated equilibrium RVG were performed at rest and exercise. Regional wall motion abnormalities were defined by agreement of 2 of 3 blinded observers. A combined strongly positive exercise ECG response was defined as greater than or equal to 2 mm ST depression or 1.0 to 1.9 mm ST depression with exercise-induced chest pain. A multivariate logistic regression model for the preexercise prediction of CAD was derived from the clinical data and selected 2 variables: chest pain class and cholesterol level. A second model assessed the incremental value of the exercise test in prediction of CAD and found 2 exercise variables that improved prediction: RVG wall motion abnormalities, and a combined strongly positive ECG response. Applying the derived predictive models, 37 of the 58 patients (64%) with preexercise probabilities of 10 to 90% crossed either below the 10% probability threshold or above the 90% threshold and 28 (48%) also moved across the 5 and 95% thresholds. Supine exercise testing with ECG and biplane RVG together, but neither test alone, effectively adds to clinical prediction of CAD. It is most useful in men with atypical chest pain and when the ECG and RVG results are concordant.

Adult↗
PubMed1983

Abdominal blood pool scintigraphy in the management of acute or intermittent gastrointestinal bleeding.

Gastrointestinal blood pool scintigraphy, using a modified in-vivo red blood cell labelling technique with technetium-99, is a new, easily performed, non-invasive procedure. It is valuable in screening patients with acute or intermittent gastrointestinal blood loss in whom duodenoscopic and sigmoidoscopic findings are unhelpful. This paper reviews the value of this scintigraphic technique over the first eight months of its use in a major teaching hospital, and compares the results with other published data. The high sensitivity of this procedure, and its ability to demonstrate gastrointestinal bleeding very strikingly, are illustrated with several examples. If used and interpreted appropriately, scintigraphy is sensitive in detecting and localizing the bleeding site, and is very helpful in indicating the optimal timing of emergency contrast angiography. The study further supports the view that scintigraphy should be the initial diagnostic imaging procedure in this group of patients, and that emergency angiography should be reserved primarily for patients in whom there is scintigraphic evidence of continuing blood loss.

Abdomen↗
PubMed1983

Impact of radionuclide techniques on evaluation of patients with ischemic heart disease.

Radiotracer studies of the heart have become clinically important in the last decade, especially for evaluation of patients with known or suspected ischemic heart disease. Radionuclide ventriculography provides quantitative measures of biventricular function and regional wall motion. Recent technical advances include the development of computer programs for analyzing diastolic function, parametric imaging methods such as "phase" analysis and methods for calculating absolute ventricular volumes. Thallium-201 scans provide maps of regional myocardial perfusion. Recent advances include development of computer programs to quantitate regional thallium-201 uptake and to calculate thallium-201 turnover rates and the development of tomographic imaging systems. Technetium-99m pyrophosphate localizes in irreversibly damaged myocardium and provides a method for diagnosing, localizing and sizing acute myocardial infarcts. Recent applications include tomographic imaging to improve image contrast and development of criteria to identify high risk patients after infarction. Two important trends affecting the application of all the radionuclide studies in clinical cardiologic practice are the increasing use of decision analysis for incorporating results of multiple tests into single diagnostic probability statements, and the use of diagnostic algorithms that include the radionuclide studies to optimize the cost effectiveness of evaluation of patients with ischemic heart disease.

Coronary Angiography↗
PubMed1983

Predictive value of an abnormal hepatobiliary scan in patients with severe intercurrent illness.

Ten patients had severe intercurrent illness and the gallbladder could not be seen on a hepatobiliary scan. In 4, surgery and pathological examination showed that the gallbladder was normal; 1 had chronic cholecystitis and 5 had acute acalculous cholecystitis. This study indicates that a positive hepatobiliary scan may not be indicative of acute gallbladder disease in the seriously ill patient.

Adult↗
PubMed1983

Topography of preemptying ventricular segments in patients with Wolff-Parkinson-White syndrome using scintigraphic phase mapping and esophageal pacing.

We analyzed the sequence of ventricular emptying using the phase image in 10 patients with accessory pathways and in 15 normal subjects. In normal subjects, the earliest emptying occurred in ventricular septal, apical and left basal segments. Eight patients had manifest preexcitation; the earliest emptying occurred ectopically in the right ventricle in one of these patients and in the left ventricle in five. The remaining two patients had normal phase maps. Two patients had concealed left-sided pathways. Their phase maps showed earliest emptying in left basal segments. Six of the 10 patients underwent electrophysiologic mapping. There was complete agreement between phase and electrophysiologic maps. Transesophageal atrial pacing increased preexcitation in one patient, normalized the ECG in another and precipitated narrow QRS tachycardia in four patients. Phase maps then showed enlargement, reduction and loss of the ectopic earliest emptying segments, respectively. We conclude that this technique in conjunction with pacing is successful in lateralizing accessory pathways.

Adolescent↗
PubMed1983

The normal and abnormal distribution of the adrenomedullary imaging agent m-[I-131]iodobenzylguanidine (I-131 MIBG) in man: evaluation by scintigraphy.

The scintigraphic distribution of m-[131I]iodobenzylguanidine (I-131 MIBG), an adrenal medullary imaging agent, was studied to determine the patterns of uptake of this agent in man. The normal distribution of I-131 MIBG includes clear portrayal of the salivary glands, liver, spleen, and urinary bladder. The heart, middle and lower lung zones, and colon were less frequently or less clearly seen. The upper lung zones and kidneys were seldom visualized. The thyroid appeared only in cases of inadequate thyroidal blockade. The "normal" adrenal glands were seldom seen and faintly imaged in 2% at 24 hr after injection and in 16% at 48 hr, in patients shown not to have pheochromocytomas, whereas intra-adrenal, extraadrenal, and malignant pheochromocytomas usually appeared as intense focal areas of I-131 MIBG uptake at 24 through 72 hr.

3-Iodobenzylguanidine↗