Scintigraphic findings in a case of lymphangioleiomiomatosis.
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Adult↗
Biomedical subjects
N Monetti
Publications and source records attributed to N Monetti.
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.
Blood Glucose↗
[Bulky mediastinal lymphomas: role of magnetic resonance and SPECT-Ga-67 in the evaluation of residual masses].
A residual mediastinal mass is a common finding during and/or after treatment for bulky mediastinal lymphoma and represents a difficult diagnostic problem. For correct therapy modulation, fibrosis must be distinguished from active disease. To assess diagnostic imaging potentials in the characterization of residual masses, 41 patients with bulky mediastinal lymphoma were examined with CT, MRI and Ga67-SPET; 92 examinations were performed for each technique: 14 before treatment, 42 during and after chemotherapy, 13 after radiotherapy and 23 six months after the end of treatment. CT provides useful pieces of information on tumor size but fails to depict tissue changes: therefore, only MR and SPET results were considered and compared with clinico-biological and follow-up findings. MRI and SPET were often in agreement with each other (78/92 cases) and with clinical data (98.7%); each examination yielded only one false positive. In case of disagreement (14/92 patients), MRI yielded more false-positive findings because it failed to differentiate neoplastic tissue from treatment-related conditions, i.e., granulation tissue, inflammation, necrosis, early fibrosis. In contrast, negative MR results were more reliable, MR negative predictive value being 100%. Ga67-SPET exhibited high sensitivity (97.1%) and specificity (91.2%), with fewer false positives than MRI (5 vs. 10). In conclusion, both examinations were accurate in the characterization of residual mediastinal masses during and after therapy, but MRI had higher sensitivity and Ga67-SPET higher specificity. Therefore, the authors acknowledge the complementary role of these two techniques and the necessity of an integrated approach, i.e., combined MRI and Ga67-SPET or CT and Ga67-SPET.
Adolescent↗
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.
Adult↗
[The high-resolution computed tomographic study of metastatic pulmonary calcifications. A case report].
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Bone and Bones↗
The effect of different dosage schedules of cisapride on gastric emptying in idiopathic gastroparesis.
The aim of this study was to determine the optimal dosage regimen of cisapride for the treatment of idiopathic gastroparesis. We studied 17 patients with documented idiopathic gastroparesis in a three-way, cross-over, double-blind study with three 4-day treatment periods separated by at least 3 days without treatment. In each period, the patients were preloaded with cisapride (10 mg tid) for three days. On the fourth day (the test day) they took either 10 mg or 20 mg before breakfast and placebo before lunch (1 x 10 mg), (1 x 20 mg), or 10 mg before breakfast and 10 mg before lunch (2 x 10 mg). The medications were taken 30 min before meals. Gastric emptying of solids (99mTc-sulphur colloid) was measured at lunch time under basal conditions and during each treatment period. Plasma concentrations of cisapride were determined before the breakfast dose, before the lunch dose, and at 1, 2, 3, 4 and 5 h after. The greatest acceleration in gastric emptying occurred with the 2 x 10 mg regimen. Although the single morning dose of 20 mg also significantly accelerated gastric emptying (P = 0.05), the reduction was not as substantial. Plasma concentrations of cisapride were significantly higher after 2 x 10 mg than after 1 x 20 mg or 1 x 10 mg. There was a significant relation between cisapride plasma concentrations and changes in gastric emptying. Peak concentrations of cisapride greater than 60 ng.ml-1 were invariably associated with acceleration of gastric emptying. We conclude that cisapride 10 mg tid before meals is the optimal dose for the treatment of idiopathic gastroparesis.
Adult↗
A comparison of rest sestamibi and rest-redistribution thallium single photon emission tomography: possible implications for myocardial viability detection in infarcted patients.
Thirty patients (26 men, 4 women, mean age 61 +/- 8 years) who had suffered myocardial infarction 15 +/- 6 months previously, were submitted to (1) standard stress-redistribution thallium-201 single photon emission tomography (SPET), (2) rest-redistribution 201T1 SPET and (3) stress-rest technetium-99m sestamibi SPET. Uptake modifications in relation to exercise-induced defects were evaluated in a total of 390 myocardial segments. Tracer uptake was scored as normal (=0), mildly reduced (=1), apparently reduced (=2), severely reduced (=3) or absent (=4). Comparison of stress studies failed to show any statistical difference (58% segmental abnormalities with sestamibi vs 61% with thallium). Uptake abnormalities (score 1-4) were detected in 55% of the segments with sestamibi, 55% with standard thallium redistribution, 55% with early imaging after thallium injection at rest and 54% with 3-h delayed rest imaging (P = NS). Absence of tracer uptake (score = 4) under resting conditions was recorded in 75 (19%) segments with standard 201T1 redistribution, 75 (19%) with rest sestamibi, 70 (18%) with rest 201T1 imaging and 62 (16%) with rst-redistribuion 201T1 (P < 0.05 vs other imaging modalities). Thus, 3-h delayed rest thallium imaging detected reversibility of uptake defects in a significantly higher number of myocardial segments. This finding might have important implications for both tracer and technique selection when myocardial viability is the main clinical issue.
Cell Survival↗
Fat-induced ileal brake in humans: a dose-dependent phenomenon correlated to the plasma levels of peptide YY.
BACKGROUND: Upper gastrointestinal motility is regulated by the presence of nutrients in the distal gut. The present study evaluated whether lipid-induced ileal brake on gastric emptying (1) can be elicited by low fat concentrations; (2) is a dose-dependent phenomenon; and (3) is related to gastrointestinal peptide release. METHODS: Seven patients were studied in the defunctionalized stage of total colectomy, on three separate occasions. On each study day, patients ate a meal labeled in the solid component; 30 minutes later, one of the following solutions was randomly infused into the ileal pouch: 0.9% saline, 2% oleic acid, and 20% oleic acid. Plasma concentrations of peptide YY (PYY), enteroglucagon, neurotensin, and motilin were measured. RESULTS: Both oleic acid solutions slowed gastric emptying compared with saline (P < 0.001), the effect being dose dependent (P < 0.001). Ileal infusions did not modify neurotensin and enteroglucagon levels but induced a dose-dependent increase of PYY (P < 0.01) and a borderline decrease of motilin (P = 0.05) levels. Slower rates of gastric emptying were related to increased plasma concentrations of PYY (r = 0.615; P < 0.05). CONCLUSIONS: This study shows that (1) the ileal brake on gastric emptying can be evoked by low doses of lipids in the distal ileum; (2) the delay of gastric emptying is related to the release of PYY; and (3) both phenomena are dose dependent.
Adult↗
Captopril renal scintigraphy: a viewpoint.
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Animals↗
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.
Adult↗
[Identification of viable myocardium by 201Tl scintigraphy: a comparison of methods].
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.
Female↗
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.
Adult↗
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.
Adult↗
Patients with duodenitis have gastric secretory and motor functions like those of duodenal ulcer patients: results of a short-term treatment with ranitidine.
Gastric acid secretion, gastric emptying of solids, and the effects of short-term treatment with 300 mg ranitidine at bedtime were evaluated in symptomatic patients with endoscopically and histologically proven duodenitis. The patients investigated had basal and pentagastrin-stimulated gastric acid hypersecretion, but normal gastric emptying times. Ranitidine brought about a significant improvement of endoscopic and histological features compared with the pretreatment findings. Endoscopic but not histological improvement was significantly better than with placebo. Furthermore, ranitidine brought about a significant reduction of weekly antacid consumption compared with placebo. Both ranitidine and placebo induced significant symptomatic improvement over basal conditions, but the difference between the two treatments did not reach statistical significance. Gastric secretory and motor functions, as well as the response to therapy, were similar in duodenitis patients with and without previous history of duodenal ulcer; the only exception was in antacid consumption, which was higher in the placebo group in those with past evidence of ulcer disease. Our results suggest that duodenitis patients have secretory and motor functions similar to those of duodenal ulcer patients. Therefore, further trials on large populations of duodenitis patients with antisecretory drugs are justified.
Adult↗
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.
Administration, Oral↗
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.
Adult↗
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.
Aged↗
Thiamine-responsive anemia in DIDMOAD syndrome.
Two children with the DIDMOAD syndrome (diabetes insipidus, diabetes mellitus, optic atrophy, deafness) developed a megaloblastic and sideroblastic anemia, neutropenia, and borderline thrombocytopenia. Plasma thiamine concentration was low in one patient and normal in the other; in both children, thiamine pyrophosphate in erythrocytes and thiamine pyrophosphokinase activity were lower than the lowest values observed in control subjects. A month after institution of treatment with thiamine, the hematologic findings had returned to normal and the insulin requirements had decreased. Withdrawal of thiamine repeatedly induced relapse of the anemia and an increase in insulin requirements. We propose that an inherited abnormality of thiamine metabolism is responsible for the multisystem degenerative disorder known as DIDMOAD syndrome.
Anemia, Macrocytic↗