The usefulness of 99mTc tetrofosmin scintigraphy in patients with breast cancer recurrences

To verify the usefulness of 99mTc tetrofosmin scintigraphy in the follow-up of breast cancer patients, we studied 72 surgically treated breast cancer patients with suspected local recurrences (20 cases) or distant metastases (52 cases) at clinical examination and/or at conventional imaging procedures (CIPs). In all patients, a whole-body scan followed by planar and single photon emission tomography (SPET) images of selected sites were acquired 10 min after the intravenous injection of 740 MBq of 99mTc tetrofosmin, using a rectangular dual-head gamma camera equipped with high-resolution parallel-hole collimators. Loco-regional recurrences were diagnosed in 19 patients and distant metastases in 44 cases, while benign lesions were ascertained in nine cases. 99mTc tetrofosmin SPET showed higher sensitivity, specificity and accuracy per patient than did CIP (96.8% vs 85%, 77.7% vs 55.5% and 94.4% vs 81.1%, respectively) with statistical significance for accuracy (P <0.05). The combined use of SPET and CIP achieved 100% sensitivity and 98.6% accuracy. Planar imaging did not give additional information in respect of either SPET or CIP, showing significantly lower sensitivity and accuracy values (47.6% and 52.8%, respectively). Our data seem to suggest that 99mTc tetrofosmin SPET, but not planar, may be useful in the follow-up for the detection of loco-regional and distant recurrences in patients with breast cancer. The technique can play a complementary role to conventional diagnostic imaging procedures in selected patients.

Synthesis, chemical, radiochemical and radiobiological evaluation of a new 99mTc-labelled bombesin-like peptide

A new pentadecapeptide bombesin analogue was prepared by Fmoc synthesis, purified by HPLC and identified by electron ionization mass spectrometry. The biological activity of the new peptide was tested on isolated human colonic muscle cells and compared to native bombesin. Labelling of the new biomolecule with Tc-99m yielded a single radioactive species which remained stable at room temperature for eight hours. In a binding assay, the radiolabelled peptide showed high affinity for oat-cell carcinoma (Kd = 9.8 nM) and colorectal adenocarcinoma (Kd = 27.2 nM). Biodistribution studies, performed in normal rodents, indicated uptake by organs that normally express bombesin receptors, such as liver, intestines and kidneys. Scintigraphic studies, performed in nude mice transplanted with small cell lung carcinoma and colon cancer cells, showed significant tumor uptake two hours p.i. The new synthetic pentadecapeptide appears to have promise for several malignancies, including oat-cell lung carcinoma, colorectal cancer and gastroenteropancreatic (GEP) tumors.

Outcome of endoscopic sphincterotomy in post cholecystectomy patients with sphincter of Oddi dysfunction as predicted by manometry and quantitative choledochoscintigraphy

BACKGROUND

Sphincter of Oddi dysfunction is diagnosed at manometry and, after cholecystectomy, non-invasively at quantitative choledochoscintigraphy. Patients may benefit from endoscopic sphincterotomy.

AIMS

The aim of this study was to assess the usefulness of choledochoscintigraphy compared with manometry in predicting outcome of sphincterotomy in post cholecystectomy patients with sphincter of Oddi dysfunction.

PATIENTS AND METHODS

Thirty patients with biliary-type pain complying with the Rome diagnostic criteria of sphincter of Oddi dysfunction and belonging to biliary group I and II were subjected to clinical evaluation, choledochoscintigraphic assessment of the hepatic hilum-duodenum transit time, endoscopic retrograde cholangiopancreatography, and perendoscopic manometry. Twenty two biliary group I and II patients with prolonged hepatic hilum-duodenum transit times were invited to undergo sphincterotomy. Fourteen patients underwent sphincterotomy; eight refused. Clinical and scintigraphic assessments were performed at follow up.

RESULTS

Hepatic hilum-duodenum transit time was delayed in all patients with manometric evidence of sphincter of Oddi dysfunction, in all biliary group I patients and in 64% of biliary group II patients. At follow up, all patients who underwent sphincterotomy were symptom free and hepatic hilum-duodenum transit time had either normalised or significantly improved. A favourable post sphincterotomy outcome was predicted in 93% of cases at choledochoscintigraphy and in 57% at manometry.

CONCLUSIONS

Quantitative choledochoscintigraphy is a useful and non-invasive test to diagnose sphincter of Oddi dysfunction as well as a reliable predictor of sphincterotomy outcome in post cholecystectomy biliary group I and II patients, irrespective of clinical classification and manometric findings.

Technetium-99m Tetrofosmin Imaging in Malignant Lymphomas

Aim

To assess the utility of 99mTc tetrofosmin (TF) scintigraphy as a diagnostic modality in lymphomas.

Methods

Seventeen patients (14 with Hodgkin's disease and three with non-Hodgkin's lymphomas; age range, 10-59 years) were investigated. Planar and SPECT images of the supradiaphragmatic region (including neck and chest) were obtained. All patients were untreated at the time of the first scintigraphy. Follow-up scans after therapy were acquired in six patients (in five twice), so a total of 28 scintigraphic studies were performed. Mediastinal, pulmonary, cervical, supraclavicular and axillary activity was evaluated and results were compared in a blinded fashion with those of CT.

Results

TF imaging demonstrated pathological focal uptake at 38 sites (16 in the mediastinum, eight in the lungs, four in the axillae, eight in the supraclavicular region and two in the cervical region) in 16 of 17 untreated patients; CT identified 24 lesions (16 in the mediastinum, two in the lungs, two in the axillae, two in the supraclavicular and two in the cervical region) in 17 patients. Scintigraphy detected 22 of the 24 lesions demonstrated by CT and revealed 16 unknown tumor sites in 10 patients. The only negative pre-treatment scintigraphy result was found in a patient with axillary lymph node involvement. On the first post-treatment scintigrams there was a reduction in the number of visualized pathological sites (seven vs 16) in five of the six patients examined. The second follow-up study demonstrated only two lesions in two of the five patients examined.

Conclusions

Our preliminary results indicate that TF imaging is effective in depicting supradiaphragmatic lymphoma lesions in untreated patients and suggest that serial scintigraphic studies may be suitable for monitoring response to treatment. However, larger series are needed to better define the possible role of TF scintigraphy in the follow-up of the response to therapy.

Immunoscintigraphy with a technetium-99m labelled anti-epithelial growth factor receptor antibody in patients with non-small cell lung cancer

BACKGROUND

A variety of human tumours, including non-small cell lung cancer, overexpress epithelial growth factor (EGF) receptors. In this study we evaluated the feasibility of immunoscintigraphy with a technetium-99m-labelled monoclonal antibody directed towards the EGF receptor (MINT5).

MATERIALS AND METHODS

The labelling with technetium-99m was performed using the glucoheptonate-iminothiolane method. Eight patients with non-small cell lung cancer were i.v. injected 740 MBq of MINT5. Neither side-effects, nor toxicity, nor HAMA response were observed. Each patient was submitted to total body planar images in anterior and posterior projections at 1-2 hours and at 4-6 hours after the injection.

RESULTS

Uptake of MINT5 was mainly visible in liver, spleen and bone marrow; it proved stable in vivo. The primary lung cancer was imaged in 7 out of 8 patients and metastases were detected in 3 out of 3 cases.

CONCLUSION

MINT5 is a safe and promising radiopharmaceutical for in vivo localization and biological characterization of non-small cell lung cancer.

Diagnostic accuracy and prognostic implications of stress testing for coronary artery disease in the elderly

BACKGROUND

The aim of this study was to define the diagnostic accuracy and the prognostic significance of stress electrocardiography (ECG) and of thallium-201 single-photon emission computed tomography (SPECT) in determining the incidence of coronary artery disease (CAD) in an elderly population.

METHODS

A selected series of 132 patients (90 males, mean age 72.4 years; 42 females, mean age 68.2 years) hospitalized because of cardiac events associated with suspected CAD, underwent stress ECG and thallium-201 testing; as endpoints we considered the heart rate and the appearance of clinical symptoms or ST segment depression. Patients unable to develop an adequate exercise workload, were tested with dipyridamole. All patients also underwent coronary angiography following the stress test. One hundred and twenty-four patients had a mean follow-up of 2 years. Endpoints included subsequent coronary events or new serious disease. The sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values of both ECG and of thallium-201 SPECT were calculated.

RESULTS

ECG findings were positive in 102 patients and coronary angiography confirmed the presence of CAD in 92 of them; ECG findings were negative in 30 patients, but only 14 were free from obstructive coronary lesions. Thallium-201 SPECT findings were positive in 112 patients (coronary angiograms confirmed CAD in 101) and negative in 20 patients (in 13 of whom angiography confirmed the absence of disease). The sensitivity of the stress tests was quite good: 85.1% for ECG and 93.5% for thallium-201 SPECT; conversely, the specificity of ECG was superior to that of SPECT (58.3 vs 54.1%). The sensitivity of both techniques was superior in males than in females and seemed to correlate with the extent of CAD.

CONCLUSIONS

The diagnostic accuracy of thallium-201 SPECT was 86.3% whereas that of ECG was 80.3%. Considering the overall cardiac events, the predictive value of SPECT was superior to that of ECG both in terms of the positive value (54 vs 51%, p = NS) and, more importantly, in terms of the negative value (84 vs 62%, p < 0.03). In fact, patients with normal thallium images were at low risk for future cardiac events.

Long-term octreotide treatment of metastatic carcinoid tumor

The optimal dosage of somatostatin analogs for the long-term control of carcinoid tumors has not yet been established. Receptor alterations induced during long term treatment with somatostatin analogs have lead to consecutive drug dosage increases in order to control carcinoid disease. In this report, we describe the rapid and effective control of tumor in a patient with metastatic carcinoid treated for nine years with a single daily dose of octreotide based on tumor marker levels. Tumoral somatostatin receptor (sst) subtype analysis by RT-PCR amplification showed the expression of sst2 subtype only. We suggest that a single daily dose of octreotide strictly related to tumor marker secretion, could have played a role in the effective long-term therapy by avoiding the phenomenon of somatostatin receptor desensitisation. Furthermore, the exclusive presence of sst2 subtype supports the high affinity of octreotide to tumoral cells.

111In-pentetreotide scintigraphy in the detection of insulinomas: importance of SPECT imaging

The aim of this study was to determine whether the systematic use of SPECT can increase the reported low sensitivity of somatostatin receptor scintigraphy (SRS) in detecting insulinomas.

METHODS

Fourteen patients were evaluated. After 111In-pentetreotide injection (approximately 250 MBq intravenously), abdominal SPECT images were obtained at 4 h and multiple planar images were obtained at 4 and 24 h. MRI and CT were performed within 1 mo of SRS. Sixteen tumors were histologically verified after surgery in 14 patients.

RESULTS

SPECT revealed 14 lesions in 12 patients (sensitivity, 87.5%), both planar SRS and MRI revealed 7 tumors in 7 patients (sensitivity, 43.8%), and CT revealed only 5 lesions in 4 patients (sensitivity, 31.3%). Moreover, in 4 patients SPECT was the only examination with positive findings.

CONCLUSION

SPECT at 4 h is mandatory for preoperative detection of insulinomas using SRS because the images are more sensitive than planar images and are superior to images from other conventional methods.

Single photon emission computed tomography procedure improves accuracy of somatostatin receptor scintigraphy in gastro-entero pancreatic tumours

In patients with gastro-enteropancreatic neuroendocrine tumours the localization of all the neoplastic lesions and an accurate staging of the diseases have important therapeutic implications. Somatostatin receptor scintigraphy with In-111 pentatreotide has proved to be useful in detecting gastro-enteropancreatic tumours; however, the role of abdominal single photon emission computed tomography has not yet been definitively established. In a series of 52 patients with gastro-enteropancreatic tumours (9 non-functioning islet cell carcinomas, 4 insulinomas, 3 somatostatinomas, 2 VIPomas, 1 glucagonoma and 33 carcinoids) we compared somatostatin receptor scintigraphy with the results of computed tomography and magnetic resonance imaging performed within one month. Four and 24-hour total body planar images and 4-hour abdominal single photon emission computed tomography were acquired after the i.v. injection of approximately 250 MBq of In-111 pentatreotide. Only abdominal localizations were considered: planar scans detected 16 extrahepatic lesions in 13 patients and 54 liver sites in 21 patients; single photon emission computed tomography visualized 31 extrahepatic lesions and 89 liver metastases in 27 and 28 patients, respectively; computed tomography and magnetic resonance imaging detected 11 extrahepatic lesions in 10 patients and 73 liver sites in 21 patients. In-111 pentatreotide single photon emission computed tomography was the only imaging method able to localize tumoural lesions in 13 patients; all these localizations were then histologically verified. The scintigraphic positivity did not depend on the site or on the presence of hormonal hypersecretions. In conclusion, our results indicate that single photon emission computed tomography is more sensitive than planar images and computed tomography/magnetic resonance imaging in detecting abdominal gastro-enteropancreatic tumours and their metastases; it is able to increase both the number of visualized lesions and that of patients with positive findings. Single photon emission computed tomography is particularly useful in patients in whom tumoural lesions have not been already localized; it should be the first imaging modality in patients with gastro-enteropancreatic tumours: its initial use will result in more information and proper management.

Technetium-99m sestamibi single-photon emission tomography detects subclinical myocardial perfusion abnormalities in patients with systemic lupus erythematosus

In patients with systemic lupus erythematosus, involvement of the cardiovascular system is the third leading cause of death. However, although autopsy studies have demonstrated a high incidence of abnormalities in both the myocardium and coronary vessels, clinical manifestations have been reported in only a small percentage of cases. The aim of this study was to evaluate myocardial perfusion in asymptomatic lupus patients using technetium-99m sestamibi single-photon emission tomography (SPET). Twenty-eight patients without overt cardiac involvement and risk factors were studied with 99mTc-sestamibi SPET at rest and after dipyridamole infusion. Perfusion abnormalities were detected in 18 cases: six had persistent defects, three had reversible defects, seven had both persistent and reversible defects, and two showed rest defects which normalized on dipyridamole images ("reverse redistribution pattern"). Coronary angiography was performed in eight patients with positive 99mTc-sestamibi SPET, and showed normal epicardial vessels in all the cases. These results indicate that 99mTc-sestamibi SPET reveals a high prevalence (18 out of 28 patients in this study, i.e. 64%) of myocardial perfusion abnormalities in asymptomatic lupus patients, probably due to the primary immunological damage of this autoimmune disease. In conclusion, rest/dipyridamole 99mTc-sestamibi SPET can be a useful non-invasive method to identify subclinical myocardial involvement in systemic lupus erythematosus, and patients potentially at risk of later cardiac events.

Technetium-99m tetrofosmin single photon emission computed tomography in the evaluation of suspected lung cancer

Technetium-99m-tetrofosmin is a radiopharmaceutical employed for myocardial imaging, which has recently emerged as useful in the visualization of tumors. In this study technetium-99m-tetrofosmin was evaluated for its accuracy in differentiating malignant from benign pulmonary lesions, and in detecting mediastinal node metastasis due to lung cancer. Eighty-one patients with a solitary lung lesion on the chest radiograph and/or CT scan were submitted to chest single photon emission computed tomography after technetium-99m-tetrofosmin injection (740 MBq i.v.). The scintigraphic findings were correlated to the final histopathological diagnosis, demonstrating abnormal tracer accumulation in 51 of 54 malignant lesions (sensitivity 94%) and in 4 out of 27 benign conditions (specificity 85%), yielding an accuracy of 91%. Mediastinal lymph-node involvement was evaluated in 35 patients with non small cell lung cancer who underwent mediastinoscopy and/or surgery. Tetrofosmin accuracy (89%) was significantly higher than that of CT (69%, p < 0.05); the false negative scintigraphic results were in nodes sized less than 1 cm. In conclusion, technetium-99m-tetrofosmin imaging is useful in distinguishing malignant from benign pulmonary lesions, and in non-invasively assessing mediastinal node metastases from non small cell lung cancer, especially in patients with enlarged nodes by CT scan.

Lupus carditis: evaluation with technetium-99m MIBI myocardial SPECT and heart rate variability

The objective of this paper was to investigate the incidence of myocardial perfusion defects in patients with systemic lupus erythematosus (SLE) associated with dysautonomic alterations. Twenty patients without any sign or symptoms of heart disease, selected from a larger population of patients with SLE, underwent technetium-99m sestamibi (Tc-99m MIBI) single photon emission computed tomography (SPECT), at rest and after dipyridamole infusion; they also underwent heart rate variability (HRV) examination by a 24 hour ambulatory electrocardiography, analyzing in the time domain the standard deviation of the R-R intervals average (SDNN) and the percentage of R-R adjacent intervals differing from each other more than 50 msec (pNN50); in the frequency domain the low (LF) and high frequencies (HF) were analyzed. Twenty healthy volunteers served as control group for heart rate variability. At MIBI-SPECT examination, the scan was found abnormal in 15 patients and normal in five: three patients demonstrated reversible defects in the anteroseptal region, four had irreversible defects in a region (two in the anteroseptal region and two in the lateral region), two had rest defects in two different regions (lateral and inferior, lateral and anteroseptal) that improved during dipyridamole scan, and six had both reversible and irreversible defects: four in a single segment (three anteroseptal and one lateral, and two in two different regions, particularly anteroseptal and lateral, lateral and inferior). All 20 patients showed significantly lower HRV parameters in comparison with the control group, except for pNN50, which indicates decreased physiologic periodic fluctuations of the autonomic nervous system. In six patients who underwent coronary angiography, the epicardial vessels were found completely normal. In view of the high incidence of myocardial hypoperfusion in patients with HRV alterations, the authors hypothesize that autonomic dysfunction may be associated with microvascular disease or metabolic alteration. They also believe that MIBI scintigraphy is a suitable technique in detecting myocardial damage in SLE patients free of clinical manifestation.

Immunoscintigraphy of venous thrombi: clinical effectiveness of a new antifibrin D-dimer monoclonal antibody

Safety and thrombus imaging capabilities of the 99mTc-labeled form of a new F(ab')2 monoclonal antibody (MoAb) against fragment D dimers from cross-linked human fibrin, previously shown to be effective labeled to 131I in detecting venous thrombi in the rabbit, were investigated. Sixteen patients (seven men, mean age: 60+/-7 years) with deep (n = three) and superficial (n = 13) venous thromboses of the lower limbs documented at echo-Doppler study underwent, 24 hours before saphenous vein stripping, a scintigraphic study after IV injection of the 99mTc-MoAb (1,129+/-275 MBq/mL), acquiring dynamic images, as well as early and delayed static images of lower limbs. Tracer activity was compared in normal and pathologic areas. At the operation, vessel wall including the thrombotic lesion was isolated, weighed, and counted. Blood radioactivity and MoAb concentration were also measured. No adverse reaction was observed after MoAb administration. Thrombus site appeared as a focal area (hot spot) of asymmetrically increased tracer uptake, already detectable at early images in all patients. All thrombi detected at echo-Doppler study (n=25) were confirmed at scintigraphic study, which showed four additional hot spots subsequently confirmed to represent thrombi at operation. Average percent ratio between pathologic and normal regions was 1.51+/-1.34 (p < 0.05) at time-activity curves, 2.27+/-1.1 (p < 0.05) at early static images, and 2.15+/-1.2 (p < 0.05) at delayed images, respectively. Thrombus-to-blood uptake ratio was 4.3+/-0.9 (p < 0.01). The F(ab')2 MoAb proved to be safe, and low levels of antimouse antibodies were detected in response, although further studies are needed to assess tolerance and effectiveness in case of a second administration in the same patient. The 99mTc-labeled MoAb was very effective in identifying venous thromboses both at deep and superficial localizations, although its sensitivity and specificity need be evaluated in a more numerous group, including also patients with different and clinically more relevant localizations, such as caval thromboses. However, the possibility of obtaining high-quality images within 4 hours of MoAb administration is clinically relevant, and carries also therapeutic implications, especially in pulmonary thromboembolism.

Single dose of octreotide stabilize metastatic gastro-entero-pancreatic endocrine tumours

BACKGROUND AND AIM

Somatostatin analogues are able to control symptoms and to detect tumour localisation in gastro-entero-pancreatic endocrine tumour patients. Few studies have evaluated the efficacy of somatostatin analogues in controlling tumoural growth during long-term treatment and, generally, a low efficacy has been reported in studies using multiple daily octreotide dosages. In the present study a single daily dose of octreotide (500 micrograms) for 1 year was used in the treatment of 10 patients with progressive gastro-entero-pancreatic metastatic tumour.

PATIENTS

Ten consecutive patients (3 females, 7 males age range 40-62 years) were studied of whom 4 had Zollinger-Ellison syndrome (2 with MEN-1), 3 had a carcinoid syndrome, and 3 had a non-functional neuro-endocrine tumour. All patients, 6-12 months before octreotide treatment, showed tumour progression. In all patients, somatostatin receptor status was assessed by Somatostatin Receptor Scintigraphy and tumoural lesions by Magnetic Resonance Imaging. Appropriate tumoural markers were also evaluated.

RESULTS

At the three-month control, two patients (non-functional) showed an aggressive progression of tumoural growth despite treatment and were excluded from the study. One patient was lost during follow-up. Of the 7 remaining patients, imaging evaluation studies revealed, after 1 year of treatment, stable disease in 6 patients, whereas a partial tumoural response was observed in one patient (gastrinoma). Biochemical tumoural markers decreased with respect to basal values of 53-78% in these seven patients at the end of therapy.

CONCLUSIONS

These results suggest that one year of octreotide in a single daily dose (500 micrograms) is effective in the long-term stabilization of tumoural progression in metastatic gastro-entero-pancreatic tumour patients.

Noninvasive estimate of bile flux through the gallbladder in humans

OBJECTIVE

The aim of this study was to assess whether a single noninvasive technique, ultrasonography, is able in vivo: 1) to evaluate the time-related patterns of gallbladder bile storage and emptying, and 2) to quantitate the amount of bile flux through the gallbladder (GB).

METHODS

Healthy volunteers were submitted to the simultaneous assessment of gallbladder volume variations by frequent serial ultrasonographic (US) measurements and of hepatic bile flow through the GB by quantitative cholescintigraphy (QC) during continuous i.v. infusion of 99 mTc-HIDA. An ad hoc mathematical analysis of US GB volume measurements was used to estimate the amount of bile flux through the GB. The QC-derived measurements of the flux of hepatic bile through the GB was used to substantiate the US-derived estimates.

RESULTS

The curves expressing the time-related GB handling of hepatic bile obtained independently from US and QC measurements were statistically equivalent, and both techniques showed that the patterns and the amount of hepatic bile handled by the gallbladder after meal ingestion is remarkably different during three successive phases. After meals, hepatic bile was mainly 1) stored in the GB in the first phase; 2) emptied from the GB in a second phase; and 3) stored in the GB in the third phase. The ultrasonographic analysis estimated that 1) 23.8+/-12.5 ml (0.44+/-0.11 ml/min), 5.1+/-3.9 ml (0.15+/-0.10 ml/min), and 33.2+/-10.5 ml (0.53+/-0.16 ml/min) of hepatic bile entered into the GB during the three successive postprandial phases, and 2) the entire amount of bile flowing bidirectionally through the cystic duct, during the observation period (132.6+/-23.3 ml) was about five-fold greater than that estimated by the usually employed variables.

CONCLUSION

The proposed mathematical analysis of frequent ultrasonographic measurements of the GB volumes enables one to estimate noninvasively the flux of bile through the gallbladder in humans.

Use of the somatostatin analogue octreotide to localise and manage somatostatin-producing tumours

BACKGROUND

Somatostatin receptor scintigraphy (SRS) and octreotide therapy have both changed the management of gastroenteropancreatic endocrine tumours, but very few data are available on the use of SRS and octreotide to visualise and treat somatostatinomas.

METHOD

The results of SRS and octreotide treatment in three somatostatinoma patients were examined.

RESULTS

SRS was able to detect extensive hepatic involvement in patient 1, one hepatic and one pancreatic lesion in patient 2, and one hepatic lesion in patient 3. Octreotide therapy (0.5 mg/day subcutaneously) was effective in decreasing plasma levels of somatostatin in all three patients. Symptoms (diabetes and diarrhoea) were greatly improved in the two patients with "somatostatinoma syndrome".

CONCLUSION

The study shows that somatostatinoma, like most other gastroenteropancreatic endocrine tumours, possesses functioning somatostatin receptors.

Functional and ultrastructural evidence of myocardial stunning after acute carbon monoxide poisoning

OBJECTIVE

To study human myocardial ultrastructural changes after carbon monoxide (CO) poisoning inducing reversible cardiac failure.

DESIGN

CASE REPORT

clinical, functional and morphologic findings.

SETTINGS

Public university-affiliated hospital and electron microscopy laboratory.

PATIENT

A 25-yr-old woman with functional evidence of cardiac failure after acute CO poisoning.

INTERVENTIONS

Hyperbaric and intensive care treatment over 10 days. Scintigraphic and cardiac angiography with endomyocardial biopsy.

MEASUREMENTS AND MAIN RESULTS

Scintigraphy with 99mTc hexakis 2-methoxy-2-isobutyl isonitrile (sestaMIBI) showed an uptake defect in the left anterior descending artery territory. The cardiac angiography demonstrated a slight hypokinesis of the superior two thirds of the anterior wall and of the septal region with completely normal coronary angiograms. Electron microscopy of left ventricular biopsies showed slight ultrastructural changes in the myocytes. In addition, large glycogen deposits were mostly associated with swollen mitochondria. The patient was discharged in good clinical condition on day 10.

CONCLUSIONS

Presence of glycogen deposits associated with abnormal mitochondria may be signs of the incapability of myocardial cells in utilizing energy substrata. In the presence of normal myocardial perfusion, our findings are consistent with the presence of a stunned myocardium-like syndrome. Early recognition and treatment of this clinical syndrome allow the prevention of myocardial infarction.

Preoperative identification of viable myocardium: effectiveness of nitroglycerine-induced changes in myocardial Sestamibi uptake

In order to predict tissue viability in infarcted myocardial areas, changes induced by nitroglycerine infusion on Sestamibi myocardial uptake were evaluated in 37 patients with previously confirmed myocardial infarction undergoing coronary artery bypass grafting, and compared with echocardiographic and perfusional changes occurring after the operation. The improvement of Sestamibi uptake after nitroglycerine correctly classified 24/26 (92%) patients showing postoperative improvement of wall motion in the infarcted area, whereas 24/31 (77%) patients with nitroglycerine-induced increase in Sestamibi uptake had improved wall motion after operation. The presence of collateral flow to the infarcted area was associated with a significantly (P < 0.01) higher increase in Sestamibi uptake both during nitroglycerine infusion and postoperatively. An increase in wall motion score after operation was associated with a significantly higher (P < 0.05) increase in Sestamibi uptake score during nitroglycerine infusion. Thus, the results of this study suggest that Sestamibi perfusional myocardial scintigraphy during nitroglycerine infusion is capable of assessing viable but chronically hypoperfused myocardium and predicting postoperative wall motion and perfusional improvement, to yield the best results in patients with evidence of collateral circulation that supplies the infarcted area.

99mTc anti-D-dimer MoAb detects venous thrombi in man

Authors' work is based on the ability of a 99mTc labelled antibody (MoAb) against D-Dimer (D-D) to visualize thrombi in man. D-Dimer is a specific epitope created during the cross-linking process of fibrin strains. Five normal volunteers and 5 patients with leg varices were given 10 mCi of 99mTc anti-D-Dimer MoAb (research approved by our Ethical Committee). Each patient gave his informed consent. Scintigraphic images were taken at 5, 60, 180 min. No adverse reaction was observed. Two patients underwent saphenous stripping 3 hrs after injection, in the other 4 patients scintigraphic images were acquired at 6 and 8 hrs. Twelve hot spots were visualized. Of these, 5 were localized during operation with a pencil-like probe and exsected. Specific activity of exsected thrombi, saphenal walls and blood samples was measured. Thrombus to vein wall ratio of 2.2 +/- 0.6 and a thrombus to blood of 3.1 +/- 0.8 was measured. In non operated patients the best scintigraphic images were obtained between 60 and 180 min. 99mTc anti-D-Dimer MoAb is a promising agent for localization of thrombi.

99Tcm-sestamibi scintimammography in patients with suspicious breast lesions: comparison of SPET and planar images in the detection of primary tumours and axillary lymph node involvement

Planar scintimammography with 99Tcm-sestamibi (99Tcm-MIBI) has been shown to be useful in diagnosing breast carcinoma. The aim of this study was to compare single photon emission tomography (SPET) and planar imaging for scintimammography with 99Tcm-MIBI in the detection of primary breast cancer and axillary lymph node involvement. Sixty-three females with mammographically suspicious lesions and 12 controls were evaluated. Dynamic images were acquired commencing immediately after the injection of the radiopharmaceutical, followed by multiple planar images in the supine and prone positions plus SPET supine imaging. A final histopathological diagnosis was achieved after surgery. A total of 66 breast lesions were considered. No focal uptake of 99Tcm-MIBI was observed in the breasts or axillas of the controls. In the patients with breast cancer, the sensitivity was 92.9% (39/42) for SPET, 71.4% (30/42) for supine and 85.7% (36/42) for prone planar imaging, respectively; the specificity was 87.5% for SPET and 91.6% for the planar scans. Metastatic axillary lymph node involvement was seen in 19 patients: the sensitivity was 84.2% (16/19) for SPET and 63.2% (12/19) for planar images; the specificity was 91.3% and 95.7% respectively. Our results confirm the high diagnostic accuracy of 99Tcm scintimammography in the diagnosis of breast cancer, and suggest that SPET is more sensitive than planar images, especially in detecting axillary lymph node involvement.

Technetium-99m sestamibi myocardial tomography based on dipyridamole echocardiography testing in hypertensive patients with chest pain

The non-invasive diagnosis of coronary artery disease in hypertensives with chest pain is an important clinical concern because all exercise-dependent tests display limited feasibility and diagnostic accuracy; by contrast, dipyridamole echocardiography testing has been shown to have a similar feasibility and accuracy in hypertensive and normotensive subjects. The aim of this study was to evaluate the diagnostic capability of technetium-99m sestamibi tomography based on dipyridamole echocardiography testing in hypertensives with chest pain, and to compare the scintigraphic results with those of coronary angiography, exercise electrocardiography and dipyridamole echocardiography. Forty subjects with mild to moderate hypertension, chest pain and no previous myocardial infarction were submitted to 99mTc-sestamibi tomography (at rest and after high-dose dipyridamole echocardiography) and to exercise electrocardiography testing. At coronary angiography 22 patients (group A) had significant epicardial coronary artery disease (>/=70% stenosis of at least one major vessel) and 18 normal main coronary vessels (group B). Dipyridamole 99mTc-sestamibi imaging was positive in 21/22 patients of group A and in 5/18 of group B. Dipyridamole echocardiography was positive in 18/22 patients of group A and in 5/18 of group B. Exercise electrocardiography was positive in 15/22 patients of group A and in 11/18 of group B. Four out of five subjects in group B with positive results in all the tests showed a slow run-off of angiographic contrast medium, probably due to small-vessel disease. Significant epicardial coronary artery disease in hypertensives with chest pain is unlikely when dipyridamole 99mTc-sestamibi tomography is negative. When scintigraphy is positive, either epicardial coronary artery disease or a small-vessel disease condition is possible. The association of scintigraphy with dipyridamole echocardiography testing allows the assessment of contractile function and myocardial perfusion by a single pharmacological stress.

Somatostatin receptor scintigraphy of malignant somatostatinoma with indium-111-pentetreotide

This article describes the visualization of a pancreatic somatostatinoma and liver metastases using 111In-pentetreotide imaging in a patient with somatostatinoma syndrome. A 61-yr-old woman with gallbladder stones, diabetes, weight loss, diarrhea and steatorrhea, immunohistochemical diagnosis of somatostatinoma (liver biopsy) and high plasma values of somatostatin was studied by somatostatin receptor scintigraphy. Six sites of focal abnormal 111In-pentetreotide hyperfixation were found: three in the liver and three in the pancreatic area. This case report demonstrates that in vivo detection of somatostatinoma with somatostatin receptor imaging is possible in the presence of high levels of circulating somatostatin, suggesting that receptor downregulation has not occurred.

Scintimammography with technetium-99m tetrofosmin in suspected breast cancer

BACKGROUND

Scintimammography with Tc-99m sestamibi has recently demonstrated a clinical usefulness in the evaluation of patients with breast lesions. The aim of this study was to assess the potential role of scintimammography using Tc-99m tetrofosmin in the detection of breast cancer.

MATERIALS AND METHODS

Fifty-five patients (age range: 33-76 years) with suspicious breast abnormalities detected by mammography, and ten controls were examined. Dynamic images (1-20 min post-injection of the radiopharmaceutical) followed by three planar views were performed. Final diagnosis was achieved by hystology after surgery or excisional biopsy.

RESULTS

A total of 59 breast lesions were considered. The sensitivity of Tc-99m tetrofosmin scintimammography for detection of primary breast cancer was 93.1% (27/29) and the specificity was 93.3% (28/30). No focal uptake was observed in both breasts of the control population.

CONCLUSIONS

Tc-99m tetrofosmin scintimammography has high diagnostic accuracy in detecting breast cancer and may have a clinical role as complement to conventional mammography.

111In-pentetreotide detection of gastrinoma before and after surgery

Eighteen patients with Zollinger-Ellison syndrome were studied with 111In-pentetreotide SPECT in order to localize gastrinoma, the tumour responsible for this pathology. NMR imaging was also carried out. Eight patients were operated. 111In-pentetreotide was reinjected 4 hours before operation and the radioactivity of the excised tumours counted. The nature of the withdrawn tissues was assessed by immunohistochemistry (chromogranina A). The scintigraphy was repeated 3-6 months after surgery. 111In pentetreotide SPECT was more sensitive than NMR. It was also absolutely specific because all the radioactive tumours excised showed positive chromogranin A staining. The radioactivity/gram counted in gastrinomas exceeded 10 fold the hepatic and biliary radioactivity and 20-100 folds the radioactivity of blood and omentum. In all the operated patients but three, the scintigraphy performed after surgery did not detect tumours. However complete eradication did not occur, because though 3-6 months after surgery the gastrinemia was significantly lower with respect to pre-surgery results it did not return to normal values in all patients but two.

In vivo study of a technetium labelled anti-EGFr MoAB

Epithelial Growth Factor receptors (EGFr) are normally present in all the epithelial cells, but their overexpression is closely related to presence of cancer. We have raised EGF-competitive antibody against EGFr and have labelled it with 131I and technetium. The ability of this antibody to bind to A431 cells to be internalized has been tested on A431 cells cultures. Its ability to give scintigraphic images of epithelial tumors has been tested on nu/nu balb c mice xenografted with A431 cells. The labelled antibody is well internalized by cultured cells. Xenografted tumors are clearly imaged both by 131I and 99mTc anti EGFr Mo/Ab. 99mTc labelling is very interesting. The tumor/background ratio was 0.72 +/- 0.2 for 99mTc and 0.40 +/- 0.6 for 131I labelling. Moreover very high uptake of 99mTc MoAb was obtained 2 hours after injection whereas the 131I antibody required 24 hours.

A three center study on the diagnostic accuracy of 99mTc-MIBI scintimammography

In order to assess specificity and sensitivity of the prone scintimammography (PSM) in a large series with 99m-Tc MIBI, we performed a three-center study; 420 patients were studied; after mammography all the patients were submitted to PSM and biopsy and/or operation. PSM was considered positive if hot spot within the breast was observed. In palpable masses sensitivity was 0.98 and specificity 0.89, non palpable masses showed a sensitivity of 0.62 and a specificity of 0.91. When the cancers were stratified for T category the sensitivity was 0.28 in T1a 0.26 in the group of T1a carcinomas, 0.56 in T1b 0.95 in T1c and 0.97 T2 tumors. Physical factors such as attenuation. Compton scattering from chest, as well as biological factors have a role in breast tumor imaging. In the tumors smaller than 1 cm biological factors are probably involved too.

Single photon emission computerized tomography increases the sensitivity of indium-111-pentetreotide scintigraphy in detecting abdominal carcinoids

Somatostatin (sms) receptors have been identified in carcinoids (c), so enabling their visualization with 111In-pentetreotide scintigraphy. The aim of this study was to evaluate if single photon emission computerized tomography (SPECT) can increase the sensitivity of sms receptor scintigraphy in the detection of abdominal c. 26 patients (pts) with a present, or previously operated, abdominal carcinoid were submitted to SPECT over the abdomen and multiple planar views after the injection of 111In-pentetreotide. Magnetic resonance imaging and computed tomography were also performed. In 19 pts abnormal sites of uptake were found by SPECT which localized 13 abdominal extrahepatic (in 11 pts) and 45 hepatic lesions (in 15 pts). No pathologic accumulation was seen in 7 pts in complete remission after surgery. Planar images visualized 7 abdominal extrahepatic (in 6 pts) and 26 liver tumor sites (in 10 pts), conventional procedures detected 5 abdominal extrahepatic (in 4 pts) and 36 hepatic lesions (in 10 pts). 111In-pentetreotide SPECT is more sensitive than planar scanning and conventional methods to detect abdominal c, and so may play a major role in the early and accurate mapping of tumour spread.

Technetium-99m sestamibi imaging in the detection of axillary lymph node involvement in patients with breast cancer

BACKGROUND

The status of the axillary lymph nodes is the most important prognostic factor in breast cancer, and the findings of axillary node dissection remain the gold standard for the patients staging and prognosis. The aim of this study was to evaluate the usefulness of Tc-99m sestamibi scintigraphy in the detection of axillary node involvement.

MATERIALS AND METHODS

Forty-nine patients (age range: 32-72 years) with breast cancer were studied. Dynamic images (1-20 minutes post-injection of the radiopharmaceutical) followed by multiple planar views and tomographic images were performed. Final diagnosis was achieved by histology after surgery.

RESULTS

Metastatic axillary lymph node involvement was present in 21 patients: sensitivity was 81% (17/21) for tomographic and 61.9% (13/21) for planar images; specificity was 92.9% (26/28) and 96.4% (27/28), respectively.

CONCLUSIONS

Tc-99m sestamibi imaging is a promising noninvasive method to detect axillary node metastases in patients with breast cancer, tomography appears more sensitive than planar views.

99mTc-sestamibi and 201-Thallium at rest: dual scintigraphic mapping of myocardial injury in infarcted patients

201-Thallium (Tl) and (99m)Tc-sestamibi (SM) present different biological properties and kinetics, suggesting a complementary evaluation of mitochondrial and cell membrane functions with subsequent implications regarding myocardial injury mapping. To verify the usefulness of a dual isotopic approach in Q infarcted patients, 30 subjects were submitted at rest, within 5 days, to SM imaging, 4h-delayed Tl scans and echocardiography (ECHO). Left ventricle segmental uptake and wall motion were graded on a 3 points scale (0=absent to 2=normal) and compared on the basis of an 11 segments model.

RESULTS AND DISCUSSION

1) The analysis of SM normal segments demonstrated a strong concordance (97%) with Tl and ECHO, suggesting that both mitochondrial and cell membrane functions are preserved; 2) 49% of SM graded 0 segments were scored 1 by Tl and ECHO, suggesting a worse impairment of mitochondrial function with respect to cell membrane function; 3) approximately 55% of segments showing a reduced MIBI uptake were found normal using Tl, then an impaired mitochondrial but a normal cell membrane function could be hypothesized. 4) Tl provided a better estimation of the effective infarction size with respect to SM.

CONCLUSIONS

The SM and Tl dual approach, allowing scintigraphic mapping of myocardial injury, seems to provide a useful tool for a complete evaluation of infarcted patients.

Nitroglycerin-induced changes in myocardial sestamibi uptake to detect tissue viability: radionuclide comparison before and after revascularization

BACKGROUND

Nitroglycerin (NTG) is known to increase the blood supply to the myocardium, and would thus increase the delivery of a perfusional tracer such as sestamibi (MIBI) to the tissue. The latter, in turn, would take up and concentrate the tracer to a greater extent than in basal conditions only if energy-dependent mechanisms were still available-that is, only if the cells were still viable.

METHODS

We evaluated the changes that intravenous administration of NTG induced on the uptake of MIBI by akinetic myocardial areas, using tomographic perfusional imaging in 23 patients with previously ascertained anterior myocardial infarction who were undergoing myocardial revascularization procedures. Changes in uptake were compared with echocardiographic and perfusional changes occurring after operation.

RESULTS

The improvement of MIBI uptake after NTG correctly identified 12 of the 16 patients (75%) showing postoperative wall motion improvement; they comprised 12 of the 14 (86%) patients with NTG-induced increase in MIBI uptake who showed improved wall motion after operation. A close correlation (r = 0.88, P < 0.001) was found between the increase in myocardial MIBI uptake induced by NTG infusion and that induced by revascularization. The presence of collaterals to the akinetic area was associated with a significantly (P < 0.01) greater increase in MIBI uptake both during NTG infusion and after operation.

CONCLUSIONS

The results of this study suggest that MIBI perfusional myocardial scintigraphy during infusion of NTG is capable of detecting viable but chronically hypoperfused myocardium, predicting postoperative wall motion and perfusional improvement, and reflecting the postoperative pattern of perfusion. The best results were achieved in patients with evidence of collateral circulation supplying the infarcted area.

Muscular uptake of Tc-99m MIBI and TI-201 in Duchenne muscular dystrophy

Lack of dystrophin, a protein localized to the inner surface of the sarcolemma of the muscle fiber, is the cause of Duchenne type muscular dystrophy. Plasma membrane damage of the muscular fiber occurs, followed by Ca++ influx into the fibers. There is severe mitochondrial damage in dystrophic but still viable fibers. Five children aged 5-7 years were studied with MRI, TI-201, and Tc-99m sestamibi scintigraphy of the thighs. These three methods showed that the sartorius is the least damaged muscle in Duchenne type muscular dystrophy. MRI showed mild damage of adductors and quadriceps; TI-201 scintigraphy showed a marked reduction of radioactivity in the same muscles; Tc-99m sestamibi uptake occurred only in the sartorius muscle; the quadriceps was not imaged and adductors showed a faint image. A decrease of water in muscular fibers as well as fatty fibrous substitution, occurs after death of the fibers, whereas plasma membrane and mitochondrial damage reduced the uptake of tracers when the fiber is still viable. The interesting mismatch between sestamibi and TI-201 can be explained by considering that the cellular mechanism of uptake and retention of Tc-99m sestamibi involves both plasma membrane and mitochondria, whereas the uptake of TI-201 is only affected by plasma membrane damage.

SPECT improves accuracy of somatostatin receptor scintigraphy in abdominal carcinoid tumors

Abdominal carcinoid tumors are often small and difficult to localize. Somatostatin receptors have been detected in carcinoids, thus enabling their in vivo visualization by scintigraphy with 111In pentetreotide, a radiolabeled somatostatin analog. The aim of this study was to determine the value of 111In-pentetreotide SPECT in the detection of abdominal carcinoids and to compare these results with the outcomes from planar scans and conventional imaging techniques.

METHODS

Eighteen patients with a present, or previously operated, abdominal carcinoid were evaluated. Abdominal SPECT scans were acquired 4 hr postinjection of 111In-pentetreotide and multiple planar views were performed at 4, 24, and 48 hr.

RESULTS

No adverse reactions were observed after radiopharmaceutical injection. In 13 of 18 patients, abnormal sites of uptake were found by SPECT, which localized 9 abdominal extrahepatic lesions (in 7 patients) and 33 hepatic lesions (in 10 patients). No pathologic accumulation was seen in the five patients considered in complete remission after surgery. Planar scans visualized 5 abdominal extrahepatic sites (in 4 patients) and 21 liver tumor sites (in 7 patients), while conventional procedures detected 3 abdominal extrahepatic lesions (in 2 patients) and 30 hepatic lesions (in 7 patients).

CONCLUSION

Indium-111-pentetreotide scintigraphy is a safe and practical procedure. SPECT appears to be more sensitive than planar scintigraphy and conventional methods to detect abdominal carcinoids; it can increase the number of visualized tumor sites and that of patients with positive findings and may therefore have a role not only in the mapping of tumor spread but also in therapeutic decisions.

[Breast scintigraphy with technetium 99m sestamibi, as support to radiologic methods in the study of breast lesions]

Our study was aimed at investigating the efficacy of scintigraphy with 99mTc-Sestamibi (MIBI) as a support to mammography and US in the diagnosis and staging of breast cancer. Twenty-seven women with breast lesions were examined: the masses, detected at mammography and US, ranged in diameter 0.7 to 2.5 cm; mass features suggested a benign lesion in 5 patients, a malignant lesion in 9 patients and a questionable diagnosis in 13 patients. 99mTc-MIBI scintigraphic images were analyzed blind by two observers and the pattern was considered positive when tracer uptake was demonstrated at the lesion. In neoplastic lesions, tracer uptake was looked for also in the axilla. All the patients were submitted to surgery and, in case of malignancy, lymphadenectomy was also performed. MIBI scintigraphy was negative in 14/16 benign lesions and positive in 9/11 malignant lesions. Tracer uptake in the axilla was observed in 3 of 5 patients with nodal involvement. Scintigraphy had 82% sensitivity, 87% specificity and 85% accuracy in the diagnosis of breast cancers.

Somatostatin receptor localization of pancreatic endocrine tumors

Gastroenteropancreatic endocrine tumors are difficult to localize. At the same time the tumor is localized, though, there is an opportunity for cure or to remove tumor tissue. In this study we have prospectively examined the ability of 111In-octreotide scintigraphy, magnetic resonance imaging (MRI), and computed tomography (CT) to localize tumor lesions in 24 patients with a biochemical or histologic diagnosis of neuroendocrine tumor. In eight patients a surgical assessment of the imaging results was prospectively performed. Planar and abdominal single-photon emission tomography (SPET) images acquired 4 and 24 hours after 180 to 220 MBq of 111In-octreotide injection were evaluated and compared with conventional imaging techniques. SPET scintigraphy visualized more presumed tumor lesions (n = 39) than conventional imaging studies (MRI,n = 25; CT,n = 13); 23 of 24 patients had positive octreotide scintigraphy, 17 of 24 had positive MRI-scans, and 12 of 24 patients had positive CT scans. It was concluded that 111In-octreotide scintigraphy combined with conventional imaging improves the preoperative localization of presumably tumorous lesions in patients with gastroenterohepatic endocrine tumors.

Myocardial scintigraphy with 99mTc-sestamibi in children with Kawasaki disease

Kawasaki disease (KD) is a systemic vasculitis syndrome of early childhood. It involves particularly the coronary arteries and may cause aneurysms and thrombotic occlusions. Echocardiography is the most useful method of detecting coronary aneurysms. Nevertheless, obstructive lesions are difficult to evaluate and often need invasive coronary angiography. An important feature of this disease is the possibility of finding coronary pathology several years after the onset. This characteristic makes KD an important cause of coronary artery disease (CAD) in young adults. Thus patients with KD and previously diseased coronary arteries should be kept under long-term control. However, coronary angiography is invasive and cannot be performed repeatedly, especially in young patients. As an alternative, thallium 201 scintigraphy has been employed, but its low-energy photons are suboptimal for standard gamma-camera imaging, particularly in children aged less than three years. To verify the usefulness of a noninvasive assessment of myocardial perfusion, the authors used rest and dipyridamole 99mTc-Sestamibi scan in 15 children (ranging from one to six years of age) with Kawasaki's cardiac involvement. Coronary aneurysms have been demonstrated by echocardiography in 12 patients; 8 patients were also submitted to cardiac catheterization. The sensitivity of 99mTc-Sestamibi imaging for detection of overall coronary lesions was 88% and the specificity was 93%. These data suggest that rest/dipyridamole 99mTc-Sestamibi scintigraphy is an accurate and noninvasive method for the detection and follow-up of Kawasaki's cardiac damage even in patients aged one year.

Sestamibi imaging and echocardiography: a combined approach to myocardial infarction

The resting relationship of MIBI segmental uptake to regional wall motion has been studied in 30 patients with postinfarction wall motion abnormalities. The purpose of this study was to verify whether an integrated approach using Sestamibi (MIBI) imaging (perfusion analysis) combined with echocardiography (ECHO) (wall motion analysis) could present an additive value to differentiate infarcted from viable myocardial areas with respect to MIBI imaging alone. The same 11 segments model for left ventricle was used to compare segmental wall motion scores versus segmental uptake scores using a chi 2 analysis. The global score frequency rates for MIBI and ECHO were examined and a subsequent comparative analysis score versus score on each segment was performed. Our data, based on a chi 2 analysis, indicated that MIBI imaging overestimates the effective area of necrosis, underestimating, furthermore, hypoperfused but non-necrotic myocardium. We can conclude that an integrated approach based on both segmental perfusion and wall motion analysis, seems to be clinically suitable for a correct evaluation of infarcted patients, especially in view of revascularization procedures, providing an additive value in discriminative capacity, with respect to MIBI scintigraphic analysis alone.

Technetium-99m sestamibi: an indicator of breast cancer invasiveness

As recently shown, angiogenesis is the most reliable marker of breast cancer invasiveness. Unfortunately it must be assessed by immunohistochemistry on tissue specimens. We have used technetium-99m sestamibi, a marker of regional blood flow in other organs that often but not always images breast cancer, to assess the invasiveness of this tumour. Nineteen patients, ten with nodal metastases and nine without any metastases, were studied with 99mTc-sestamibi scintigraphy before operation. Angiogenesis was quantitatively assessed by immunohistochemical staining of endothelia for factor VIII. All the node-positive (N+) patients at surgical revision showed a positive 99mTc-sestamibi scan of the primary tumour and all the N-patients were negative. Nine out of ten N+ and sestamibi-positive tumours showed more than 135 microvessels/mm2 and one showed 99 microvessels/mm2; by contrast there were 71.6 +/- 12.1 microvessels/mm2 in the nine N- and sestamibi-negative tumours. Our study suggests that 99mTc-sestamibi is a marker of breast cancer invasiveness: its uptake is related to angiogenesis and, possibly, to oxidative metabolism of the tumour.

[Clinical use of echo-dipyridamole test in hypertensive subjects with suspected ischemic heart disease]

The aim of this study was to assess the diagnostic capacity of the dipyridamole-echocardiography test (DET) and dipyridamole myocardial scintigraphy (DMS) for coronary artery disease in mild to moderate hypertensive subjects with chest pain. A comparison was performed with exercise stress test (EST) and stress myocardial scintigraphy (SMS) in 20 subjects. Seven patients also underwent coronary angiography. To compare test results, Mc Nemar test was employed. Our results showed a statistically significant difference between DET and EST and a good agreement, in terms of dichotomy response, between DET and SMS. Any difference was further found between SMS and DMS. In conclusion, in hypertensive subjects, DET appears to provide a useful clinical noninvasive tool for coronary artery disease diagnosis and evaluation.

Radioisotope assessment of heart damage in hypertransfused thalassaemic patients

Twenty-five thalassaemic patients treated with repeated blood transfusion (BT) and intensive iron removal therapy were studied by echocardiography and rest/stress equilibrium gated radionuclide angiocardiography (EGNA). Stress left ventricular ejection fraction (LVEF) showed an important negative correlation with number of BTs (r = -0.75). Abnormal values of stress LVEF were measured after 200 BTs: these data demonstrate the effectiveness of stress LVEF in the follow-up of patients who have undergone repeated BTs and the clinical importance of intensive chelation therapy. Peak filling rate did not show diagnostic value in the early detection of iron cardiotoxicity. However, its inverse correlation with BT (r = -60) indicates that iron overload depresses the diastolic parameters.

Anti D dimer monoclonal antibodies: a possible scintigraphic agent for immunodetection of thrombi

The aim of this work was to produce a MoAb able to react with clots but not with fibrinogen. Monoclonal antibodies directed towards DD dimers, against specific products of plasmic digestion of cross-linked fibrin, were obtained. One of these antibodies, F 60/43/8, showed a 1.79 x 10(9) l mol-1 binding constant in spite of the presence of fibrinogen at a 4000 times greater concentration than the cross-linked fibrin. In vitro studies with 125I-F(ab')2 of F 60/43/8 showed that 34-80% of the radioactivity can be found in human clots, in the presence of physiologic concentrations of fibrinogen, and that 96-h washing does not remove the labelled F(ab')2 from the clot. 131I-F(ab')2 was injected into rabbits in which a clot had formed in an artery (six rabbits) or in a vein (six rabbits) of the left ear. Scintigraphic images of the clot were always obtained. In conclusion, the results of this work suggest that F 60/43/8 may be used as a specific antibody for the radioimmunodetection of thrombi.