Predicting late restenosis after coronary angioplasty by very early (12 to 24 h) thallium-201 scintigraphy: implications with regard to mechanisms of late coronary restenosis.

To examine whether late coronary restenosis may be predicted by abnormalities of myocardial perfusion in the early hours after successful percutaneous transluminal coronary angioplasty and to study in greater detail the mechanisms involved in the development of late coronary restenosis after angioplasty, a prospective study was undertaken in 90 consecutive patients. Thallium-201 scintigrams were recorded at rest and during the stress of atrial pacing, 12 to 24 h after angioplasty, and the results were related to the findings at angiography in 70 patients undergoing late cardiac catheterization. A reversible thallium-201 perfusion defect was found in 39 (38%) of 104 myocardial regions supplied by the dilated coronary vessel and identified a subset of patients at high risk of late (6 to 12 months) angiographic restenosis (sensitivity 77%, specificity 67%). In contrast, late coronary restenosis developed in only 7 (11%) of 65 vessels and in 5 (14%) of 37 patients with a nonischemic thallium-201 scintigram on day 1 (p less than 0.005). Multivariate logistic regression analysis of 14 possible preangioplasty and periangioplasty clinical and angiographic variables selected reversible perfusion defect on the thallium-201 scintigram on day 1 (p = 0.016) and immediate postangioplasty residual coronary narrowing (p = 0.004) as significant independent predictors of late restenosis, with younger patient age as an additional less powerful predictor (p less than 0.05). The findings have important implications regarding the pathogenesis of late coronary restenosis in patients undergoing successful angioplasty and they imply that in the majority of these patients pathophysiologic events in the early minutes and hours after angioplasty may determine the development of late restenosis.

Bone scintigraphy in hungry bone syndrome following parathyroidectomy.

A 59-yr-old man with chronic renal failure was admitted for evaluation of generalized skeletal pain and frontal bone mass, which was lytic on radiography. Bone scintigraphy demonstrated several foci of moderately increased uptake, without involvement of the skull mass. Radiographs of these lesions were compatible with brown tumors. Serum parathormone level was elevated and CT demonstrated a lower right cervical mass, consistent with parathyroid tumor. Following the removal of the mass and decrease in parathormone levels, the patient suffered from a prolonged period of hypocalcemia and his bone pain worsened. Repeat bone scintigraphy showed an increase in the number and intensity of the areas of focal uptake, consistent with hungry bone syndrome. This flare-up phenomenon is due to an increase in bone metabolism and is an uncommon finding following parathyroidectomy for primary hyperparathyroidism.

Early and late lesion-to-non-lesion ratio of thallium-201-chloride uptake in the evaluation of "cold" thyroid nodules.

Forty-nine consecutive patients with "cold" thyroid nodules were studied using early and late visual and semiquantitative measurements of 201Tl uptake in the nodule to differentiate benign from malignant nodules. The visual method compared 201Tl uptake in the nodule to the normal thyroid tissue. The semiquantitative method used a lesion-to-non-lesion (L/N) ratio of the same areas. Both measurements were carried out early (15 min) and late (3 hr) following 201Tl injection. The reproducibility of the method for the early and late measurements was tested for intraobserver and interobserver variability as well as for repeatability coefficients. The visual method resulted in 43% sensitivity and 79% specificity for the detection of malignant nodules. The L/N method showed that an early threshold of 1.55 chosen by receiver characteristic analysis had a sensitivity of 57% and a specificity of 86%, while the late ratio of 0.99 had a sensitivity of 100% and a specificity of 62%. It is concluded that a L/N 201Tl uptake method performed 3 hr following 201Tl injection is superior to a visual scoring method as well as to the early L/N 201Tl uptake in detecting malignant thyroid nodules.

Bone scintigraphy in scurvy.

Scintigraphic bone changes in two cases of scurvy are described, the cause being subperiosteal hematoma. Generalized increased uptake was shown in the affected femur at an early state of the disease. At a late stage, marked uptake both in the femoral shaft and surrounding tissue was seen causing scintigraphic appearance of widened ("club-shaped") femur.

Uptake of gallium-67 citrate and [2-3H]deoxyglucose in the tumor model, following chemotherapy and radiotherapy.

Uptake of 67Ga and [3H]DG after radiation and chemical therapy was measured in a tumor model. Uptake of both agents in treated viable tumors did not differ significantly from the uptake in viable control tumors. However, when tumors showed, after therapy, partial or complete fibrosis, there was a significant decrease in uptake. Viable tumors showed the whole range of weight response to therapy, and the mean weight of viable tumors did not differ significantly from the mean weight of partially viable tumors. The results indicate that, in the tumor model used in this study, 67Ga and [3H]DG could be used to monitor tumor response to therapy. Tumor weight was not a reliable indicator of the effect of therapy at early stages when the tumor is partially viable.

Cinematic display of respiratory organ motion with impedance techniques.

A technique is described for the recording of individual images during discrete phases of the respiratory cycle, i.e., isovolume images. The method is based on the observation that transthoracic impedance is related approximately linearly to lung volume. This impedance signal can be converted to an FM signal to stimulate a Z pulse, then added in parallel to the Z pulse from the gamma camera. Simulated X and Y position signals locate simulated Z at the periphery of the computer field of view. Summation of the images with coinciding simulated Z counts produces isovolume images, one for each phase of respiration. These images then can be displayed in cinematic mode or as motion-corrected images. This new technique offers a potential for improved image resolution, temporal separation of organs that exhibit different motion patterns, and estimation of regional pulmonary function.

Semiquantitative skull planar and SPECT bone scintigraphy in diabetic patients: differentiation of necrotizing (malignant) external otitis from severe external otitis.

UNLABELLED: Early diagnosis of necrotizing external otitis (NEO) includes the use of bone scintigraphy since clinical assessment alone cannot differentiate the necrotizing type of otitis from the severe type of external otitis in which there is no extension to the adjacent bone. Four-hour planar bone scintigraphy may reflect soft-tissue infection, and therefore may not be useful in distinguishing NEO from severe external otitis (SEO). Twenty-four-hour bone scintigraphy using planar or SPECT imaging may better reflect bone uptake and increase the accuracy of the test. METHODS: Twenty-six diabetic patients (12 diagnosed NEO; 14 SEO) and 10 nondiabetic (ND) patients were studied. Lesion-to-nonlesion (L/N) count ratios obtained from planar and SPECT imaging at 4 hr, 24 hr and 24 hr/4 hr (24/4) were assessed. RESULTS: Count ratios obtained from the 4- and 24-hr planar and SPECT images were significantly higher in the NEO patients compared to SEO patients for both planar and SPECT studies (p < 0.001, 0.005). The 24/4 count ratio was also significantly higher in the NEO patients on the planar (p < 0.01) and the SPECT studies (p < 0.001). The ND patients were not different from SEO patients on 4-hr planar, 4- and 24-hr SPECT as well as 24/4-hr planar and SPECT studies. The L/N count ratio threshold yielding the best sensitivity for detecting NEO was 1.05 for the 24/4 SPECT study. CONCLUSION: In diabetic patients, an early distinction between NEO and SEO patients can be reliably made by using L/N count ratios on 24/4 or 24-hr SPECT bone scintigraphy.

A dual collimator design for beat-to-beat measurement of cardiac performance with an Anger camera.

A dual collimator was designed for an Anger camera to permit measurement of cardiac performance on a beat-to-beat basis. Special all-purpose (SAP) and special high-sensitivity (SHS) collimator sections can be interchanged without movement of the patient. Thus, left-ventricular regions of interest delineated on SAP multigated images can be transferred to SHS dynamic images to generate beat-to-beat volume curves. Preliminary balloon studies demonstrated an excellent correlation between ejection fractions calculated with the two collimators: r greater than 0.99, n = 17, p less than 0.001. Varying the volume of an adjacent "right ventricle" balloon failed to alter significantly the count rate from the "left ventricle" balloon's region of interest. Preliminary results on 12 patients, comparing standard-camera ejection fractions with average beat-to-beat ejection fractions, showed that is is possible to measure cardiac function on a beat-to-beat basis with a single-crystal gamma camera. There was minimal difference between the ejection fractions calculated by the dual-collimator method and a standard gated technique (r = 0.98, n = 12, p less than 0.001).

In vivo SPECT quantitation of bone metabolism in hyperparathyroidism and thyrotoxicosis.

Bone metabolism was assessed in vivo and noninvasively using quantitative SPECT. The effect of endocrine abnormalities on bone metabolism was studied in 27 patients with primary hyperparathyroidism (HPT) and 12 patients with thyrotoxicosis (TTX). Quantitative bone scintigraphy (QBS) values of 99mTc-MDP uptake were compared to normal values matched for sex and age. Bones with significantly increased QBS values indicating increased bone metabolism were identified in the two patient groups. Fifty-one percent of the bones in patients with HPT and 78% in patients with TTX showed significantly increased QBS values. Increase in bone metabolism was highest in the femoral shaft. Seven patients with HPT and five with TTX were successfully treated. Six patients with HPT and four patients with TTX showed significant decrease of bone metabolism with normal QBS values after three months. The results indicate that QBS can be used to evaluate bone metabolism and its response to treatment in individual bones in patients with endocrine abnormalities.

The prognostic value of perfusion lung scintigraphy in patients who underwent single-lung transplantation for emphysema and pulmonary fibrosis.

UNLABELLED: The objective of this study was to evaluate the role of quantitative perfusion lung scintigraphy (QPLS) in predicting the development of chronic rejection in patients who underwent single-lung transplantation. METHODS: Eighteen patients (15 men, 3 women; age range, 41-60 y; mean age, 54.6+/-6.0 y) who underwent single-lung transplantation for emphysema (n = 14) or pulmonary fibrosis (n = 4) were studied. Patients were evaluated using QPLS and pulmonary function tests before surgery and at 1-3 mo and 1-3 y after transplantation. Relative perfusion of the transplanted lung was calculated from standard perfusion lung scintigrams. Values for forced expiratory volume in the first second (FEV1) were obtained from lung function tests at the same time points. The maximal and minimal relative perfusion and FEV1 values in the early (1-3 mo) and late (1-3 y) follow-up periods were identified for each patient. Receiver operating curve (ROC) analysis was performed on all parameters. RESULTS: In total, 82 lung scans were performed (mean, 4.8+/-1.55 per patient) and 484 FEV1 test determinations were obtained (mean, 30.0+/-15.6 per patient) during a follow-up period ranging from 8 to 84 mo (mean, 39.6+/-19.3 mo). In 7 of the 18 patients, chronic rejection developed, whereas 11 patients had a favorable outcome. No significant difference was found in the number of complications (acute rejection and infection episodes) between patients with a favorable outcome and patients with chronic rejection, up to 1 y after transplantation. At 1-3 mo, minimal relative perfusion values were 67.1%+/-12.2% in the favorable outcome group and 50.8%+/-9.6% in the chronic rejection group (P = 0.02). Before surgery and at 1-3 y, minimal relative perfusion was not significantly different between the 2 groups. The difference in maximal relative perfusion at 1-3 y was marginally significant, with 76.5%+/-8.9% in the favorable group and 64.3%+/-15.0% in the chronic rejection group (P = 0.051). FEV1 values were not significantly different preoperatively and 1-3 mo after surgery between the chronic rejection and the favorable outcome groups. Late in the follow-up period (1-3 y), FEV1 values in the chronic rejection and favorable outcome groups were 35.6%+/-7.9% and 56.9%+/-13.6%, respectively (P = 0.002). ROC analysis of minimal relative perfusion at 1-3 mo identified a threshold of 57% under which the sensitivity and specificity for chronic rejection were 83% and 88%, respectively. Minimal FEV1 for the same period identified a threshold of 48% under which the sensitivity and the specificity were 80% and 67%, respectively. CONCLUSION: QPLS early after transplantation in our patients predicted the development of chronic rejection in patients with single-lung transplantation for emphysema and pulmonary fibrosis, whereas surgical complications, acute rejection, infection episodes, and lung function tests did not predict the outcome. This early prediction could not be obtained from lung function tests performed at the same time.

Bone turnover in cortical and trabecular bone in normal women and in women with osteoporosis.

UNLABELLED: This study is based on the assumption that is bone turnover, shown by the uptake of 99mTc-MDP, indicates a high rate of bone loss in patients with osteoporosis, it could potentially predict bone loss in patients at risk before significant bone loss has occurred. METHODS: Quantitative bone SPECT (QBS) using 99mTc-MDP, expressed as the %ID/cc x 10(-3), was performed in 71 women who had osteoporosis in the lumbar vertebrae, the femoral neck or both, and in 54 age-matched normal female controls. Of the women with osteoporosis, 42 had postmenopausal osteoporosis and 29 had primary hyperparathyroidism (HPT) and osteoporosis. RESULTS: QBS increased with age in the cortical bone and decreased in the trabecular bone of the normal women. Quantitative bone SPECT in the femoral neck was 3.18 +/- 1.20 and was 2.73 +/- 1.06 in the femoral shaft in 20 women with postmenopausal osteoporosis of the femoral neck. In 19 women with HPT and osteoporosis of the femoral neck, the QBS value in the femoral neck was 3.57 +/- 0.92 and in the femoral shaft 3.38 +/- 1.12. These values were also significantly higher for the femoral neck and for the femoral shaft than those of normals. Although QBS values were higher in the lumbar region in 39 women with postmenopausal osteoporosis (4.59 +/- 1.45) and in 27 women with HPT (4.30 +/- 1.52), as compared with the normal group (4.28 +/- 1.61), the difference was not statistically significant. CONCLUSION: This study shows that bone turnover is significantly higher in the cortical bone of women with osteoporosis than in normal women.

Prediction of bone loss in patients with primary hyperparathyroidism using quantitative bone SPECT.

UNLABELLED: Bone loss is a major complication of primary hyperparathyroidism (PHPT), and it has significant implications in the treatment of this disease. Bone turnover was measured in patients with PHPT, using quantitative bone SPECT (QBS), to determine if the rate of bone loss could be predicted before a significant decrease in bone mass occurs. METHODS: Forty-six patients were included in the study. QBS and bone mineral density (BMD) of the lumbar spine (LS) and femoral neck (FN) were done at baseline. The percent deviation of QBS in patients with PHPT from the values in normal matched controls was calculated. BMD was measured again after a mean of 17.5 mo in 38 patients, and in 29 patients a repeat BMD study was done after a mean of 41.4 mo. The change in BMD in patients with high and normal QBS values was compared using the nonparametric Mann-Whitney test. Regression analysis tested the correlation between baseline QBS values and BMD changes over time. RESULTS: For the FN, there was a statistically significant difference in the BMD change between patients with high and normal QBS values for short-term follow-up (-2.82%+/-4.80% versus 1.45%+/-4.67%, p < 0.05) and for long-term follow-up (-3.53%+/-5.34% versus 0.92%+/-2.40, p < 0.02). There was a negative correlation in the FN, r=-0.48 between QBS values and the percentage of change in BMD. There was no significant difference between the percentage of change in BMD in the LS in patients with high and normal QBS values for either short- or long-term follow-up. CONCLUSION: The results of this study show that QBS can predict bone loss in the FN in patients with PHPT. QBS can thus indicate the need for surgery at an early stage of the disease to prevent bone loss.

Observer variation in the interpretation of bone scintigraphy.

To assess the reliability of bone scintigraphy, a random sample of 100 bone scans was reviewed twice by each of two physicians. Observer variation in the description and interpretation of bone scintigrams varied by diagnosis. Good to excellent k values were obtained for inter- and intraobserver variation in relation to metastasis or normal scans. For degenerative bone disease, as well as the specific agreement on major pathologies other than metastases, k values were found to be moderate. The agreement on the need for further radiographic studies was poor to moderate. The interpretation of bone metastases or normal scintigrams was found to be more reliable in a research setting than in the usual clinical framework, and the latter requires improvement. The interpretation of bone scintigraphy as consistent with degenerative changes is not reliable. The diagnosis should be evaluated by radiography.

External imaging of atherosclerosis in rabbits using an 123I-labeled synthetic peptide fragment.

The oligopeptide fragment of apolipoprotein B, SP-4, has demonstrated pronounced uptake in the healing edges of balloon-injured rabbit aortic endothelium. To assess 123I-labeled SP-4 for identification of atherosclerotic plaques by gamma camera imaging, 14 Watanabe heritable hyperlipidemic (WHHL) and 5 normal rabbits were imaged 5 minutes and 12 and 24 hours after intravenous injection of 123I-SP-4. In addition, two WHHL and two normal rabbits were injected with 125I-SP-4 for autoradiography. Twelve of the 14 WHHL, but none of the normal, rabbits had visually apparent focal radioiodine accumulation in the region of the aorta. Focus-to-lung and focus-to-heart count ratios were 2.4 +/- 1.3 and 1.0 +/- 0.4, respectively. Five of the visually positive WHHL rabbits were reimaged 4 and 8 weeks later with 123I-NaI and 123I-SP-2 (an apo E peptide), respectively, as negative controls. Perceptible, but faint, aortic localization of 123I-NaI and of 123I-SP-2 was seen in only one animal each. The distributions of atherosclerotic lesions on photographs of the opened WHHL aortas and of film blackening on 125I-SP-4 autoradiograms were identical. In contrast, the two normal rabbit aortas did not exhibit plaques on photographs or film blackening on autoradiograms. Thus, in an animal model closely simulating human atherosclerotic disease, SP-4 localizes specifically in aortic atherosclerotic lesions.

Decreased melatonin secretion in a phenotypically male 46,XX patient with classic 21-hydroxylase deficiency.

The possible role of gonadal steroids and gonadotropins in regulating melatonin secretion has been suggested in clinical syndromes of the hypothalamic-pituitary-gonadal axis. We describe the results of melatonin secretion in a 37-year old male patient who presented with azoospermia. The patient was an XX male, had classic simple virilizing form of 21-hydroxylase deficiency, which led to a masculine phenotype. He was ovariectomized at the age of three years and reared as a male. Melatonin production (aMT6s) was determined at baseline and during 12 months of replacement therapy. Results were compared with those obtained in age-matched male controls. Pretreatment aMT6s values were decreased (14.3 microg/24 h vs. 29.0+/-5.5 in controls). Dexamethasone replacement was associated with an increase in aMT6s values (19.3-20.9 microg/24 h). The addition of testosterone to dexamethasone replacement resulted in normalization of aMT6s (27.6-33.1 microg/24 h) and serum 17OH progesterone, testosterone and estradiol levels. The present data indicate that androgen excess due to 21 hydroxylase deficiency is associated with decreased melatonin secretion. These results support the hypothesis that sex steroids modulate melatonin secretion.

Synergistic effect of captopril and dobutamine on left ventricular pressure-volume and pressure-shortening relations in severe cardiac failure.

The acute effects of captopril and dobutamine, alone and in combination, on left ventricular contractility were assessed from left ventricular end-systolic pressure-volume and pressure-shortening relations in 6 patients with severe end-stage cardiac failure. Dobutamine was given by constant intravenous infusion on two occasions 48 hours apart, on one of these occasions the patient also received oral captopril in a dose of 37 +/- 12 mg 6-hourly. Pressures and cardiac index were measured, and left ventricular volumes and ejection fraction computed from simultaneously recorded radionuclide ventriculography. Dobutamine alone did not cause a statistically significant increase in stroke index, stroke work index, cardiac index and ejection fraction, although pulmonary capillary wedge pressure and right atrial pressure fell (P less than 0.05). There was no change in systemic or pulmonary vascular resistance nor in arterial blood pressure. Following administration of captopril, diastolic arterial pressure decreased (P less than 0.05), and the dobutamine challenge produced a greater and significant rise in stroke and stroke work index (P less than 0.05) and cardiac index (P less than 0.01). The left ventricular contractile state was unaltered by captopril but appeared to increase with dobutamine and more so during combined therapy with captopril and dobutamine, indicating a synergistic effect of the two drugs when given in combination.

Quantitative bone and 67Ga scintigraphy in the differentiation of necrotizing external otitis from severe external otitis.

Qualitative technetium Tc 99m bone scintigraphy using phosphate compounds and gallium 67 scintigraphy were described as a helpful means in diagnosing necrotizing external otitis (NEO). They were, however, claimed to be nonspecific. Quantitative Tc 99m methylene diphosphonate bone scintigraphy and gallium 67 scintigraphy were performed in eight patients with NEO and in 20 patients with severe external otitis, in order to prove usefulness of scintigraphy in the diagnosis of NEO. Ratios of lesion to nonlesion for bone scintigraphy were 1.67 +/- 0.16 in patients with NEO and 1.08 +/- 0.09 in patients with severe external otitis, and for gallium 67 scintigraphy they were 1.35 +/- 0.24 in NEO patients and 1.05 +/- 0.03 in patients with severe external otitis. There was no difference in uptake between diabetic patients with severe external otitis and nondiabetic patients. The scintigraphic studies were also evaluated using a qualitative scoring method (scores 0 to +4), according to the intensity of the radiopharmaceutical uptake. This method was found to be inferior in the diagnosis of NEO compared with the quantitative method. We conclude that lesion-to-nonlesion ratios greater than 1.5 and 1.3 on bone and gallium 67 scintigraphy, respectively, are indicative of NEO. Quantitative bone scintigraphy, which is quicker to perform, may be used as a single imaging modality for the diagnosis of NEO.

Hyperbaric oxygenation for necrotizing (malignant) otitis externa.

Two patients with extensive necrotizing otitis externa have been treated by hyperbaric oxygenation. One patient had facial nerve palsy and the other suffered from skull base involvement. Due to severe side effects, the preferred combined intravenous antibiotic therapy was changed to monotherapy in one case and completely withdrawn in the second. This was done before the commencement of hyperbaric oxygenation, while the necrotizing infection was still active. Hyperbaric oxygenation therapy was followed by complete resolution of the necrotizing otitis externa, which did not recur. The pathogenesis of the disease and mechanisms by which hyperbaric oxygenation might be of benefit are described. We conclude that hyperbaric oxygenation should be considered as adjuvant therapy for necrotizing otitis externa whenever a therapeutic pressure chamber is available.

Scintigraphic assessment of technetium 99m-diphosphonate uptake, vascularity and vessel permeability in human bone tumours.

Differences in the rate of uptake of 99Tcm-diphosphonate were found in 20 human bone tumours investigated. As some tumours have a slow rate of uptake it is suggested that the time used for routine scintigraphy at 3 hours is not always optimal and a further study should be performed in some cases. Various degrees of tumour vascularity and vessel permeability were found. The rate of diphosphonate uptake correlates with the vascularity, while it does not correlate with permeability which is generally increased as compared to normal bone.

Effect of isosorbide dinitrate on cardiac output in severe cardiac failure: relation to initial hemodynamics, ventricular volume, and the preload reserve mechanism.

Isosorbide dinitrate (ISDN) improves the clinical and hemodynamic state of patients with heart failure, but may cause dizziness and syncope. To characterize patients in whom cardiac output falls with high-dose nitrate therapy and to examine further the pathophysiology of the fall in cardiac output in these patients, we studies the effect of sublingual ISDN on forward cardiac output in 14 patients with severe cardiac failure (New York Heart Association grades 3-4). We examined systolic and diastolic left ventricular (LV) function from pressure and volume analyses of LV function. After administration of 15 mg ISDN, cardiac output was either unaltered or increased in 7 patients (Group 1) (11 +/- 12%, mean +/- SD), and decreased in 7 (Group 2) (-13 +/- 10%) (Group 1 vs. 2, p less than 0.002). Initial systemic arterial pressure, LV ejection fraction, wedge and LV transmural filling pressures were similar in both groups, but Group 2 patients had a lower systemic vascular resistance (p = 0.07) and tended to have a larger initial LV end-diastolic volume and increased end-diastolic compliance; following ISDN the decrease in LV filling pressure and end-diastolic volume was larger and the product of the changes greater (p less than 0.02). Thus ISDN decreases filling pressure and improves forward cardiac output in some patients with congestive heart failure, but large doses may decrease cardiac output in a subset of patients who have a lower systemic vascular resistance and a larger more compliant ventricle, maintaining forward blood flow predominantly by a preload reserve mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)