[Cerebral single-photon emission-computed tomography. A semiquantitative analysis of vascular areas in patients with cerebrovascular pathology]. / Tomografía cerebral por emisión de fotón único. Análisis semicuantitativo de territorios vasculares en pacientes con patología vascular cerebral.

BACKGROUND: Brain SPECT perfusion studies in patients with cerebral stroke may be useful to evaluate distant perfusion abnormalities. METHODS: 99mTc-HMPAO brain SPECT studies were performed in 17 patients with ischemic lesions in the basal ganglia and/or internal capsule demonstrated by NMR. Regions of interest were adjusted in representative transverse slices to the vascular territories of the anterior, middle, posterior and communicating cerebral arteries. RESULTS: Patients with ischemic lesions in the right basal ganglia showed increased cerebral perfusion in the left middle artery territory (0.95 +/- 0.13 versus 0.80 +/- 0.06; p = 0.0365). Patients with ischemic lesions in the left basal ganglia showed increased perfusion in the right anterior artery territory (0.93 +/- 0.09 versus 0.82 +/- 0.09; p = 0.0464), in the left anterior artery territory (0.93 +/- 0.09 versus 0.83 +/- 0.14; p = 0.0464), in the left middle artery territory (0.92 +/- 0.09 versus 0.78 +/- 0.05; p = 0.0079) and in the left posterior artery territory (1.05 +/- 0.14 versus 0.90 +/- 0.09; p = 0.036). Patients with ischemic lesions in the right internal capsule showed increased perfusion in the right posterior artery territory (0.95 +/- 0.11 versus 1.10 +/- 0.18; p = 0.0431). CONCLUSIONS: These results show the presence of delayed luxury perfusion phenomena in regions distant from the ischemic site.

[New techniques in nuclear cardiology: SPECT, PET and antimyosin]. / Nuevas técnicas en cardiología nuclear: SPECT, PET y antimiosina.

Nuclear Cardiology offers non-invasive techniques of high reproducibility for cardiovascular assessment. These techniques have advanced enormously in the latest years. The advances in areas such as general technology and computer systems, medicine, immunology and research, allow us to obtain and interpret cardiac information with immediate or potential clinical applications unavailable few years ago. This paper describes 3 of these new techniques in nuclear cardiology: Single Photon Computed Tomography (SPECT); Positron Emission Tomography (PET) and; the use of an Antimyosin monoclonal antibody.

Gastric emptying of two radiolabelled antacids.

The rate of gastric emptying of two antacids, magaldrate and Maalox, was investigated using scintigraphy. Successful labelling of the antacids was carried out with 99mTc. The stability of the 99mTc-labelled antacids was satisfactory and there was no difference in antacid capacity between the labelled and unlabelled antacids. The studies were carried out on 15 healthy male volunteers. After an eight hour fast each subject ingested a standardised meal of 95.7 MJ (400 kcal). One hour later 10 ml of one of the two antacids previously labelled with 99mTc was administered. Serial detection by anterior and posterior projection of the amount of antacid retained in the stomach was performed to determine gastric emptying of antacid. One week later the study was repeated under the same conditions with the other antacid also labelled with 99mTc. The mean (SD) percentages of antacid retained in the stomach fit a linear model with a t1/2 of 86.6 (15.3) minutes for magaldrate and 52.3 (5.2) minutes for Maalox (p less than 0.01). When the mean percentages of retention at six time intervals were compared for both antacids, it was found that Maalox emptied much faster (p less than 0.01 at 15 and 30 minutes, p less than 0.02 at 45, 60, 75, and 90 minutes).

Assessment of anthracycline-induced myocardial damage by quantitative indium 111 myosin-specific monoclonal antibody studies.

To assess chemotherapeutically induced myocardial damage, myosin-specific antibody scans and ejection fraction measurements were performed in 32 patients with breast cancer and in 9 patients with other tumours. All patients had received chemotherapy including anthracyclines. The ejection fraction decreased by less than or equal to 10% in 14 of 41 (34%) patients after chemotherapy. Antimyosin uptake in the myocardium was observed in 38 of 41 (92%) patients after chemotherapy. Antimyosin uptake was quantified by means of a heart-to-lung ratio, revealing a correlation between the degree of antimyosin uptake in the myocardium and the cumulative dose of anthracycline. Patients with a decreased ejection fraction showed more intense antimyosin uptake, indicating more severe myocardial damage. A higher degree of antimyosin uptake was found in 17 breast cancer patients treated with doxorubicin compared with 15 patients treated with mitoxantrone. We conclude that antimyosin studies provide a sensitive, non-invasive method to monitor myocardial damage in patients treated with anthracyclines. Antimyosin uptake in the myocardium precedes ejection fraction deterioration. This technique may be helpful in the early identification of patients at risk of congestive heart failure during chemotherapy including anthracyclines.

Indium-111-antimyosin scintigraphy after doxorubicin therapy in patients with advanced breast cancer.

Indium-111-antimyosin (111In-antimyosin) scans were performed in 20 women with advanced breast cancer after 10 cycles of chemotherapy consisting of cyclophosphamide, 5-fluorouracil and doxorubicin (total cumulative dose of doxorubicin of 500 mg/m2). Antimyosin uptake in the myocardium was quantified by means of a heart-to-lung ratio (HLR). Antimyosin uptake in the myocardium was observed in 17/20 (85%) patients, and HLR after chemotherapy was 1.86 +/- 0.25. Left ventricular ejection fraction (EF) was determined before and after chemotherapy. Patients with decreased EF (8/20, 40%) presented with more intense antimyosin uptake (HLR of 2.11 +/- 0.10 versus 1.70 +/- 0.16 (p = 0.01]. HLR values correlated with EF values after chemotherapy (r = -0.47, p less than 0.05). Positive antimyosin studies after chemotherapy including doxorubicin, indicate the presence of myocardial damage in these patients. Antimyosin studies are a sensitive method to detect myocyte damage in patients after doxorubicin therapy.

Transient alterations in cardiac performance after a six-hour race.

Ten long distance runners were enrolled in a 6-hour competitive race. Immediately after the race technetium-99m-albumin gated blood pool scans were performed and indium-111 antimyosin was injected. Forty-eight hours later antimyosin scans were obtained and control gated blood pool scans were performed. Left ventricular ejection fraction was higher after the race (65 +/- 5 vs 60 +/- 7%, p less than 0.01) due to a decrease in end-systolic counts. Right ventricular ejection fraction was lower after the race (42 +/- 7 vs 54 +/- 12%, p = 0.03) due to an increase in both end-diastolic and end-systolic counts. A longer systolic period was observed after the race (53 +/- 5% of the RR interval vs 39 +/- 3%, p = 0.005). No significant differences were observed in peak filling or peak emptying rates after the race. An increase in pulmonary blood volume (116% of control) was observed after the race. Antimyosin scans were normal in 7 athletes and minimal antimyosin myocardial uptake was seen in 3. Transient alterations in biventricular performance present after the race correspond to function adaptation to strenuous exercise and are not due to irreversible myocyte damage.

[Clinical application of radioimmunolocalization in colorectal cancer]. / Aplicación clínica de la radioinmunolocalización en el cáncer colorrectal.

We present preliminary results of radioimmunolocalization (RIL) of colorectal cancer with 131I labelled F(ab')2 fragments from monoclonal anti CEA and anti CA 19.9 antibodies in 22 patients with colorectal cancer and in one patient with metastases of unknown origin and high CEA value. Positive images were obtained in 7 of 11 primary tumors from 10 patients evaluated preoperatively; in 2 of 3 recurrences; in 9 of 12 metastatic localizations and in the unknown primary tumor localized, finally in the cecum. One local recurrence was not detected by any diagnostic methods, but RIL. There was not false-positive images. Therefore, RIL appears as a promising method for the diagnosis and follow-up of colorectal cancer.

[Circumferential profiles versus visual analysis in studies of myocardial perfusion during exertion using thallium-201]. / Perfiles circunferenciales versus análisis visual en los estudios de perfusión miocárdica de esfuerzo con talio-201.

Two methods of analysis for perfusion myocardial studies with thallium are compared: the conventional visual analysis, and a quantitative method which shows results as circumferential profiles. Three hundred and ninety myocardial segments in 65 patients were studied. Visual analysis showed abnormalities in 44/65 (68%) patients, the quantitative method did it in 53/65 (81%). When localization and/or extension discrepancy between the two methods was found, angiography was always concordant with circumferential profiles findings. Total agreement between the two methods was present in 20/65 (31%) patients. The quantitative method is more sensitive than the visual analysis. It is also more precise in defining localization and extension of thallium defects.

[Utility of myocardial scintigraphy with Tc-99m methoxy-isobutyl-isonitrile in the diagnosis of coronary disease]. / Utilidad de la gammagrafía miocárdica con metoxi-isobutil-isonitrilo-99mTc en el diagnóstico de la enfermedad coronaria.

We have studied 24 patients (21 males and 3 females) with coronary artery disease. Stress and rest myocardial scintigraphy was performed in all cases with 15-20 mCi of Tc99m methoxy-isobutyl-isonitrile. The examination was done in 2 sessions. Usually the stress scan was obtained and within 2-4 days the rest study was obtained. All patients underwent selective coronary arteriography within a week of the scintigraphy and, in 13 cases, rest radiologic ventriculography was also performed. In 5 patients coronary arteriography and myocardial scintigraphy were normal. In 19 cases the coronary arteriography showed lesions, the myocardial scintigraphy showed ischemia or necrosis in 17 of them and was normal in two. To localize the pathologic vessel the myocardium was divided into 3 segments and segmentary analysis localized the abnormal coronary artery in 51 out of 72 cases. The best availability of the new myocardial agent and the results obtained make it a good tracer for myocardial studies.