Bartter's syndrome: renal scintigraphic appearance after captopril administration.

We report a case of Bartter's syndrome, a rare disease characterized by hypokalemia, increased plasma renin and angiotensin II levels with normal blood pressure. During the diagnostic work-up, the patient had renal scintigraphy in baseline and after captopril administration. Pharmacological blockade of the renin-angiotensin system with captopril resulted in bilateral and symmetrical renal abnormalities (increase of parenchymal transit time, time to maximum activity and retained cortical activity, with cortical trapping of the radiopharmaceutical). Baseline scintigraphy was normal. The findings are consistent with Bartter's syndrome pathogenesis. Captopril renography may be useful to differentiate Bartter's syndrome from other covert causes of hypokalemia.

Diagnosis of renovascular hypertension with captopril renal scintigraphy in a patient with a solitary kidney.

A patient with a solitary kidney due to renal agenesis and contralateral kidney perfusion impairment due to renal artery stenosis was successfully treated with percutaneous transluminal renal angioplasty. Preintervention diagnostic work-up included captopril renal scintigraphy, which was suggestive of high probability of renovascular hypertension. Scintigraphic assessment 2 mo after angioplasty failed to show any abnormality after captopril administration, a finding in line with blood pressure beneficial response to renal artery revascularization. A 12-mo follow-up confirmed cure of hypertension.

Dipyridamole technetium-99m-2-methoxy isobutyl isonitrile tomoscintigraphic imaging for identifying diseased coronary vessels: comparison with thallium-201 stress-rest study.

A same-day double injection protocol employing 99mTc-methoxyisobutyl isonitrile (MIBI) and myocardial single-photon emission computed tomography (SPECT) for detecting coronary artery disease (CAD) was assessed in 30 patients. SPECT was performed 1 hr after a first injection (250 MBq) of 99mTc-MIBI, given after 0.56 mg/kg dipyridamole (DPD) infusion. Patients were then reinjected at rest (750 MBq) and were reimaged 1 hr later. Within 1 wk, all patients underwent a complete stress-rest SPECT thallium study. Of the 330 myocardial segments evaluated, 25 were judged ischemic by both techniques, while persistent defects were demonstrated in 50 and in 47 with 99mTc-MIBI and 201TI, respectively. Six regions were considered for diseased vessels identification. Sensitivity and specificity for CAD were 100% and 75%, respectively, for both 201TI and 99mTc-MIBI. Sensitivity for identification of diseased vessels by 201TI was 68% for LAD, 89% for RCA, and 80% for LCX as opposed to 75%, 89% and 80%, respectively, by 99mTc-MIBI. Specificity was 93% in both cases for LAD, 73% and 63% for RCA, and 53% and 46% for LCX.

Use of technetium-99m-MAG3 for renal scintigraphy after angiotensin-converting enzyme inhibition.

Technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) was tested in 82 hypertensive patients submitted to renal scintigraphy 1 hr after oral premedication with 50 mg of Captopril. Baseline studies were obtained only for those patients showing abnormal findings in the provocative study. All patients underwent renal arteriography. Sensitivity and specificity for the detection of renal artery stenosis (RAS) greater than 50% were 89% and 91%, respectively. After Captopril administration, tracer parenchymal transit time increased significantly in ischemic kidneys (334 +/- 93 sec in baseline conditions versus 468 +/- 96 sec after Captopril, p less than 0.001) but not in kidneys with no RAS or RAS less than 50% (243 +/- 46 sec versus 271 +/- 95 sec, p = ns). False-positive responses were mostly bilateral and associated with a marked decrease in blood pressure. Technetium-99m-MAG3 is an effective compound for detecting RAS greater than or equal to 50% with Captopril renal scintigraphy. Performing the provocative test as a first step considerably reduced the number of scintigraphic studies required.

Detecting hibernated myocardium with SPECT and thallium-glucose-insulin infusion.

UNLABELLED: Because thallium kinetics, like potassium kinetics, may be affected by serum insulin levels, we performed two pilot studies to identify severely ischemic myocardium using different protocols based on the infusion of a thallium, insulin, potassium and glucose solution. Results were compared with those obtained with two currently used protocols based on rest injection or reinjection of 201Tl. METHODS: In the first study (Protocol 1) of 15 men with a previous large myocardial infarction, perfusion was evaluated by SPECT in 20 segments after a 30-min infusion of 201Tl (111 MBq), insulin (5 U) and potassium (10 mEq) in 10% glucose solution (250 ml). Imaging was repeated 30 min later and the results were compared with those obtained from stress and 3-hr reinjection images. In the second study (Protocol 2), 15 patients were evaluated randomly at rest and 3 hr later (rest-redistribution). On a separate day, the patients were then re-evaluated after infusion of 201Tl (111 MBq), potassium (10 mEq) and insulin (5 U) in 5% glucose (250 ml); images were obtained 90 and 180 min postinjection. RESULTS: In Protocol 1, radiotracer activity in segments with no uptake during stress was detected in 35% with the reinjection technique and 58% with the insulin solution protocol. In Protocol 2, 31% of segments revealed thallium activity after insulin infusion but not at rest or rest-redistribution. Serum measurements showed high insulin levels (444 +/- 138 in Protocol 1, 125 +/- 33 mU/ml in Protocol 2), although glucose levels were not significantly altered (149 +/- 32 versus 71 +/- 20 mg/dl, respectively). Potassemia was not affected and the patients tolerated the tests satisfactorily. CONCLUSION: These results confirm that continuous infusion of 201Tl with a low dose of insulin in a glucose/potassium chloride solution is safe and may enhance cellular uptake of the radiotracer in severe ischemic regions, thereby improving viable myocardium detection.

Early pulmonary involvement in systemic sclerosis assessed by technetium-99m-DTPA clearance rate.

UNLABELLED: Systemic sclerosis (SS) is frequently associated with interstitial lung disease, but clinical symptoms and radiologic abnormalities may occur late in the course of the disease. This study investigated early pulmonary involvement by assessing the clearance rate of inhaled 99mTc-diethylenetriaminepentaacetic acid (DTPA). METHODS: Sixteen patients with proved SS, no clinical pulmonary symptoms and normal chest radiogram were prospectively studied. The 99mTc-DTPA clearance rate was calculated as the time to half clearance (T1/2) and compared with values obtained in healthy nonsmokers. RESULTS: Six patients showed abnormally increased clearance (T1/2 < 53 min). Rapid clearance was not correlated to SS disease duration or to abnormal pulmonary function tests. Five of six patients with abnormally increased clearance underwent high-resolution CT, which in all five demonstrated pathologic findings that were suggestive of early interstitial disease. CONCLUSION: These findings indicate that in SS asymptomatic patients may frequently present with abnormal 99mTc-DTPA clearance; 99mTc-DTPA lung scintigraphy may allow early detection of subclinical pulmonary involvement in SS.

Prognostic value of captopril renal scintigraphy in renovascular hypertension.

This study evaluates the prognostic value of captopril renal scintigraphy in hypertensive patients undergoing renal artery revascularization. Preoperative studies of 51 patients were correlated with blood pressure results at 6- and 12-mo follow-up. Captopril-renal scintigraphy was carried out 1 hr after oral administration of 50 mg of captopril, using either 220 MBq of 99mTc-DTPA or 74 MBq of 99mTc-MAG3, followed by a baseline study in case of abnormal results. Evidence of amelioration or normalization in relation to captopril study was considered predictive of blood pressure control following treatment. Blood pressure response was favorable in 37 patients, but failed to show any improvement in 14. The scintigraphic test was positive in 33 patients (15 cured, 17 improved, 1 failed) and negative in 18 (3 cured, 2 improved, 13 failed). Sensitivity and specificity for renovascular hypertension was 86.5% and 93%, respectively. For blood pressure cure and improvement, the test had positive and negative predictive values of 97% and 72%, respectively. A positive preoperative captopril renal scintigraphic result is a strong predictor of hypertension curability by renal artery revascularization.

Evaluation of hypertensive patients by means of captopril enhanced renal scintigraphy with technetium-99m DTPA.

One-hundred five hypertensive patients underwent conventional renal scintigraphy followed 2 or 3 days later by Captopril-enhanced renal scintigraphy, performed 1 hr after premedication with 50 mg of Captopril per os. All patients were then submitted to renal arteriography, performed within 15-30 days. Fifty-five patients had no renal artery stenosis, 29 had unilateral disease, and 21 bilateral. Overall, 34/37 patients were diagnosed by the provocative test as having at least one renal artery affected by a stenosis greater than 50%. Of those with no stenosis (n = 55) or stenosis less than 50% (n = 13) only two cases were falsely positive. Thus sensitivity was 92% and specificity 97%. For single kidney identification with stenosis greater than 50%, sensitivity of renal scintigraphy after Captopril administration was 94% and specificity 98%. Captopril enhanced renal scintigraphy is thus suggested as the first test to be performed in hypertensive patients referred for renal scintigraphic studies. Only those cases with equivocal results require a baseline study for better assessment.

Relationship between plasma endothelin-1 levels and myocardial ischemia induced by exercise testing.

At peak exercise, plasma endothelin-1 concentration increases in patients with effort angina as well as thallium-201 radionuclide perfusion defects; the opposite occurs in patients with normal scans and in healthy volunteers. It is concluded that exercise-induced ischemia correlates with enhanced endothelin-1 production.

Clinical and hemodynamic effects of long-term administration of gallopamil in patients with coronary artery disease and normal or impaired left ventricular function.

The hemodynamic and clinical profiles of gallopamil, a new calcium antagonist, were evaluated in 20 patients with severe coronary artery disease in a placebo-controlled, single-blind study. The patients were divided into 2 groups depending on baseline ejection fraction (greater than 45 or less than or equal to 45%) and underwent nuclear ventriculography, both at rest and during bicycle exercise under electrocardiographic monitoring, after 3 weeks of therapy (50 mg 3 times daily) and the 1-week run in and washout placebo periods. The mean anginal weekly frequency per patient was significantly reduced, from 3.4 to 0.5 (p less than 0.001). The left ventricular ejection fraction, cardiac volumes, ejection and filling indexes at rest and for the same workload were not altered in the population as a whole or in each of the 2 groups. The rate pressure product during exercise was reduced for the same workload from 18.0 +/- 5.0 X 10(3) to 16.8 +/- 4.7 X 10(3), while the regional ejection fraction in ischemic regions was not significantly changed. Individual variations of ventriculographic parameters in both groups were not related to basal values. Gallopamil increased the total duration of exercise from 432 +/- 201 to 537 +/- 188 s (p less than 0.001). Six patients did not complain of angina and their exercise was interrupted because of muscular weakness. The hemodynamic and clinical responses did not differ when the results in the population as a whole and in each of the 2 groups were compared. Gallopamil was effective and well tolerated, even in patients with very depressed cardiac function.

A phase-II clinical trial of 4'-epi-doxorubicin in advanced solid tumors.

Sixty-six patients with advanced solid tumors were treated with 4'-epi-doxorubicin at a dose of 90 mg/m2 by rapid IV injection every 21 days until the disease had progressed or to a maximum cumulative dose of 540 mg/m2. Myelosuppression, nausea and vomiting, and alopecia were the almost frequent side effects, but their incidence seemed lower than that after a comparable dosage of doxorubicin. After a cumulative dose of 540 mg/m2 a significant decrease of QRS complex deflection on the electrocardiogram was detected, but no case of congestive heart failure was observed. Partial remission and minor remission were achieved, respectively, in nine (15%) and five (9%) out of 59 evaluable patients for a median duration of 6 months. Partial remission occurred in anthracycline-sensitive tumors like breast cancer (4 of 13), lung cancer (1 of 17), head and neck cancer (1 of 8), gastric cancer (2 of 4), and ovarian cancer (1 of 1).

Monitoring bulky mediastinal disease with gallium-67, CT-scan and magnetic resonance imaging in Hodgkin's disease and high-grade non-Hodgkin's lymphoma.

Treatment of both Hodgkin's disease (HD) and high-grade non-Hodgkin's lymphoma (HG-NHL) with bulky presentation at diagnosis frequently results in residual masses detected radiologically. Conventional diagnostic radiology and computed tomography (CT) are generally unable to detect the differences between tumor tissue and fibrosis. Gallium-67-citrate (67Ga) SPECT and magnetic resonance imaging (MRI) can potentially differentiate residual active tumor tissue and fibrosis. Thirty-three patients with HD or HG-NHL presenting with bulky mediastinal disease were studied with CT, 67Ga SPECT, and MRI (only for 16 patients) at diagnosis, after two-thirds of their chemotherapy, at the end of chemotherapy, and after radiotherapy in order to evaluate the mediastinal region on the basis of persistence of residual masses and activity of pathological tissue. After treatment, all patients with 67Ga-negative (30/33) disease are still in continuous complete response. Among the three 67Ga-positive patients, 2 relapsed within one year and another one is still alive without evidence of disease. Regarding MRI, two patients were found to be positive, one of them concomitant with 67Ga-positivity; both patients survive in complete response. In lymphoma patients with bulky mediastinal presentation, the 67Ga SPECT remains the preferable imaging technique for monitoring and differentiating the eventual active residual tumor. In combination, CT and 67Ga SPECT represent a suitable complete imaging approach to the radiological diagnosis which may be useful in these particular patients. MRI could probably be considered as a second-line method and from our data would be used only in selected cases because of the high cost, accessibility, and lower specificity as opposed to 67Ga SPECT in evaluating potentially active residual disease.

[Identification of viable myocardium by 201Tl scintigraphy: a comparison of methods]. / Identifizierung des vitalen Myokards mit der 201Tl-Szintigraphie: Ein Vergleich der Methoden.

The present study was undertaken to compare four different imaging approaches to evaluate uptake defect reversibility. 24 infarcted patients underwent standard stress/redistribution 201Tl imaging (R1). Then, after reinjection of 37 MBq of 201Tl, patients were re-imaged either after 15 min (R2) 24 h later (R3). A separate rest study (R4) following a new tracer injection was done within 2-3 days. Planar images were obtained in the standard three views and subdivided into 216 segments for qualitative analysis based on a visual score. A semiquantitative analysis based upon circumferential profiles was also applied. A stress defect was found in 127 segments (58.7%). By visual inspection reperfusion was considered to occur in 32.3%, 41.7%, 33.0% and 49.6% of the cases with R1, R2, R3, and R4, respectively. The semiquantitative method showed a high reperfusion only with R1 (62%), while the other procedures proved less effective. No improvement was found with R4. Six patients (25%) showed myocardial viability that was not detected with the early reinjection technique.

Reproducibility of a solid and of a liquid caloric meal for gastric emptying studies.

Simple meals are required for routine scintigraphic gastric emptying studies. We evaluated the reproducibility of a caloric liquid meal (520 kcal) compared to that of a solid meal (638 kcal) in 8 and 11 healthy volunteers, respectively. Gastric emptying rates and half-times were similar in two tests using the same meal, while the methods used to express lag times were not highly reproducible. The emptying rates and half-times of the liquid meal were delayed after the intake of bellafoline. In conclusion, this study demonstrates that: (a) gastric emptying rates and half-times are reproducible parameters for the expression of scintigraphic gastric emptying studies; (b) mathematical methods to express lag times are not highly reproducible; (c) a 500 kcal liquid meal is sensitive to the effects of bellafoline, a drug able to delay gastric emptying. Further clinical evaluation is required to test its applicability in routine studies.

Childhood obesity: results of a multicenter study of obesity treatment in Italy.

The prevalence of pediatric obesity is increasing and many patients are followed by specialized centers or private doctors. The aim of this study was to verify short- and medium term results of a therapeutic approach based on nutritional intervention in a large pediatric population: 1383 subjects (695 females, 688 males) aged 10.1 +/- 2.7 yr, followed in 11 pediatric departments in Italy. No difference was found between centers in age, height, weight, BMI and IBW. The drop-out rate after the first visit was 30.2% (58.1% IBW > 140%) in females and 34.2% (70.7% IBW > 140%) in males. After two years of follow-up only 9.7% of females and 6.4% of males remained on treatment. Of these patients only 7.3% of females and 6.4% of males had IBW < 120%. These data show that an approach based on nutritional intervention alone is not sufficient for long-term treatment of pediatric obesity. Only an approach started early and involving the family can produce permanent results.

Cerebral SPECT with 99mTc-HMPAO in extracranial carotid pathology: evaluation of changes in the ischemic area after carotid endarterectomy.

The authors report their experience in studying patients undergoing carotid endarterectomy with simple photon emission computed tomography (SPECT). This technique made it possible to identify areas of preoperative cerebral hypoperfusion in 54.8% of the patients which had a good correlation with neurological symptoms. To distinguish gradual changes in the ischemic lesions, a method of assessing the surface of the hypoperfused areas was adopted. In addition, SPECT made it possible to detect a greater number of hypoperfused areas even in sites other than those revealed by CT. Moreover, there was good correlations between the SPECT data and the grade and site of the carotid lesion and the data provided by some intraoperative monitoring procedures. The Authors therefore propose the use of SPECT in the evaluation of patients with cerebrovascular insufficiency following a carotid disease.

Carotid endarterectomy. Pre- and post-operative monitoring with cerebral SPECT.

In the pre-operative evaluation of carotid endarterectomy, the knowledge of ischemic areas may be helpful to reduce the operative risk. A positive CT scan is often correlated with an increased operative risk. The single photon emission computed tomography (SPECT) allows us to visualize ischemic areas not shown by the CT; these areas are almost always correlated to neurological symptomatology. In patients with positive CT scan, the ischemic areas shown by SPECT are generally larger, because this technique visualize the ischemic area surrounding the cerebral infarct (penumbra). After carotid EA, SPECT is useful to show the hemodynamic modifications induced by this operation. In a series of 15 patients we observed an improvement of the cerebral blood perfusion characterized by the normalization of the blood flow in 7/12 (58%) of the ischemic areas observed pre-operatively), an improvement in 3/12 and a normalization or an improvement in the contralateral hemisphere in 5/7 of the areas. In conclusion SPECT is a useful technique to study the cerebral pathophysiology of both cerebrovascular disease and its surgical treatment.

Evaluation of lung clearance of inhaled pertechnegas.

Pertechnegas is a new ventilation agent produced by modifying the atmosphere of combustion of Technegas. Due to its rapid disappearance from the lungs, Pertechnegas has been suggested as useful in measuring pulmonary epithelial permeability. This study aimed to assess the reliability of ventilation scans with Pertechnegas to evaluate alveolar-capillary permeability. Six non-smokers with no evidence of pulmonary disease were investigated. Scintigraphic data were used to evaluate the site of Pertechnegas deposition (by assessing the Penetration Index [PI] of the gas), its clearance rate (by calculating the time to half-clearance [T1/2]) and its lung distribution (by means of a pixel-by-pixel analysis. PI measurements produced a mean value of 88.8 +/- 13.3% (range 69-117%). Time activity curves showed a fast clearance in all cases (mean T1/2 = 10.7 +/- 2.1 min, range 8.1-14.3 min). Comparison of statistical indices of uniform deposition (skewness and kurtosis) indicated satisfactory homogeneity of Pertechnegas distribution throughout the lungs. These data show that after inhalation Pertechnegas has a peripheral deposition and a homogeneous distribution in the lungs and is rapidly cleared through the alveolar-capillary barrier. In conclusion Pertechnegas can be recommended as a potential radiopharmaceutical for studying the pulmonary epithelial barrier.

Detection of renal artery stenosis by means of captopril renal scintigraphy in patients with multiple renal arteries.

Both captopril renal scintigraphy (CRS) and conventional arteriography were retrospectively evaluated in 64 patients to study CRS efficacy in hypertensive patients with multiple renal arteries (MRA). The presence of MRA was angiographically demonstrated in 9 patients, 7 unilaterally and 2 bilaterally, with a total of 11 kidneys supplied by 2 or more arteries. Overall, 25 MRA were identified and 7 were affected by stenosis of > 50%, causing a reduction of arterial supply in 5 of 11 kidneys. CRS correctly diagnosed all five ischemic kidneys (true positives) and five of six nonischemic kidneys (true negatives); in one case in which perfusion was not reduced, the CRS diagnosis was falsely positive. In the presence of MRA, CRS proved effective in identifying renal artery stenosis of > 50%, involving either one or all the MRA. This study shows that the presence of MRA is not a drawback in the evaluation of renal artery stenosis by means of CRS.