Diagnosis and staging of children's lymphoma using the technetium-labelled somatostatin analogue, 99mTc-depreotide.

Somatostatin receptor scintigraphy (SRS) is useful in diagnosing tumours with increased expression of somatostatin receptors. Lymphoma cells are known to express somatostatin receptors; however, the application of indium-labelled analogues in children is limited. The aim of this study was to investigate whether the technetium-labelled somatostatin analogue, depreotide, may be useful in diagnosing and staging malignant lymphoma in children. Fifteen children (mean age 13.8 years) with malignant lymphoma were studied (eight with Hodgkin's lymphoma and seven with non-Hodgkin's lymphoma). All children were investigated for verification of staging established by other modalities. Imaging was performed 3-5 h after administration of 300-550 MBq (99m)Tc-depreotide. All patients underwent whole-body scan and single-photon emission tomography of the chest and/or abdomen. Images were assessed visually. In all patients, foci of increased tracer uptake were found. The neck and thorax were the most frequent lesion localisations. Abdominal lesions were found in four patients, and bone lesions in three. In two patients, diffusely increased uptake was observed throughout the skeleton (verified as representing bone marrow involvement). In 11 patients, the number of abnormal sites detected by SRS was greater than that detected by CT. Based on radionuclide examination, three children were upstaged and none were downstaged. It is concluded that (99m)Tc-depreotide shows increased accumulation in pathological sites in malignant lymphoma in children. SRS with (99m)Tc-depreotide provides a single-day imaging method with high sensitivity in lymphoma and with all the advantages of a technetium-labelled compound. Further studies are required on the specificity and the possible value of (99m)Tc-depreotide in the follow-up of these patients.

Long lasting effect of physical stress on the LVEF.

BACKGROUND: Animal and clinical studies have shown that exercise can deteriorate myocardial contractile function. The aim of this study was to examine whether the decrease of LVEF measured with gated SPECT lasts as long as 3 hours after exercise. MATERIAL AND METHODS: 46 patients with CAD and a control group comprising 10 healthy subjects were studied. All patients underwent myocardial perfusion gated SPECT with (99m)Tc-tetrofosmin at rest and during stress. SPECT was started 1 hour p.i. at rest and twice - 1 hour and 3 hours after injection at stress. LVEF values were calculated by the method of Germano, using QGS software. RESULTS: LVEF values measured at all time points were significantly lower in CAD patients than in control group. In normals mean LVEF values 1h after rest injection were similar to those obtained 1 and 3 hours after stress injection (59.0 +/- 4.1 v. 60.0 +/- 5.9 v. 58.0 +/- 4.6 respectively; p > 0.05). One hour post exercise a decrease of LVEF was observed in 2 patients and 3 hours after injection also in 2 patients. CAD subjects showed slightly lower LVEF values determined 1h after stress than 1 hour after rest injection (50.8 +/- 13.6 v. 49.3 +/- 12.8; p < 0.05). More expressed reduction of LVEF was observed 3 hours after stress injection as compared to both rest and stress study (50.8 +/- 13.6 v. 46.0 +/- 12.2; p < 0.001 and 49.3 +/- 12.8 v. 6.0 +/- 12.2; p < 0.001 respectively). One hour post exercise, a decrease of LVEF values was observed in 18 patients and 3 hours after injection in 36 patients out of 46. CONCLUSIONS: In the majority of patients with CAD physical stress applied for the purposes of myocardial perfusion SPECT study results in an impairment of the LV function. The impairment of the LVEF caused by physical stress is observed 1 hour after exercise, but it increases markedly in frequency and grows stronger during the next 2 hours. Patients with CAD who underwent cardiac examination connected with physical stress should remain under observation for several hours after termination of exercise.

The influence of nitroglycerin on myocardial 99mTc-Tetrofosmin uptake defects in coronary artery disease.

Nitroglycerin (Ntg) is known to increase blood flow to the hypoperfused myocardial area and thus to reduce regional ischaemia of the heart muscle in coronary artery disease (CAD). The aim of this study was to assess the effect of a therapeutic dose of Ntg on 99mTc-Tetrofosmin uptake defects occurring in patients (pts) with CAD in myocardial SPECT at rest. The study population comprised 34 pts with CAD. All subjects underwent myocardial perfusion SPECT at rest, using 2-day, protocol. On the first day 99mTc-Tetrofosmin was injected in baseline conditions and on the second day, after sublingual administration of 0.5 mg Ntg. The baseline examination revealed altogether 78 Tetrofosmin uptake defects in all 34 pts. The SPECT after Ntg showed improved tracer uptake in 33/78 perfusion defects in 18/34 pts, no change in 29/78 defects in 7/34 cases and more reduced tracer uptake in 16/78 defects in 9/34 pts. No explicit, significant relationship was found between 99mTc-Tetrofosmin uptake changes after Ntg on the one hand and the number of involved vessels, degree of coronary artery stenosis, history of myocardial infarction and LV global and regional function on the other. It is concluded that sublinqual administration of Ntg may result in improvement as well as in deterioration of regional perfusion defects, assessed with 99mTc-Tetrofosmin in CAD. The relationships between Ntg-augmented changes in uptake defects of this tracer on the one hand and conditions of the LV function and severity of heart muscle perfusion abnormalities on the other are unclear and should be verified on a larger study population.

Effect of biventricular pacing on heart function evaluated by gated blood pool study in patients with end-stage heart failure.

BACKGROUND: Biventricular cardiac pacing has been used as a complementary form of therapy in patients with severe heart failure. The aim of this study was to evaluate the effect of the synchronous stimulation of both ventricles on the heart function measured by gated blood pool study (GBP). MATERIAL AND METHODS: Ten patients (9 men and 1 woman aged 53-74 years) with end-stage heart failure (HF) were studied. In all patients long-term biventricular pacing (BV) was applied. The obtained results were compared with single-chamber stimulation in 5 patients and with sinus rhythm (SR) in 8 patients. All patients underwent repeated GBP with RBC labelled with 740 MBq of 99 mTc-pertechnetate. The LVEF was calculated according to the standard method based on the count rates. Phase analysis was performed with the standard method using first Fourier element. RESULTS: Clinically in almost all patients moderate to important symptomatic improvement has been observed. The analysis of LVEF values revealed that BV pacing resulted in significantly higher values only in comparison with SR (21.6% +/- 10.3 v. 20.1% +/- 10.1; p < 0.05). The phase shift between both ventricles by BV pacing was positive and similar to that obtained with SR and RV stimulation (14.0 degrees +/- 29.6 v. 13.4 degrees +/- 37.6 and 7.4 degrees +/- 26.5 v. 6.0 degrees +/- 17.1 respectively). However, in comparison with LV pacing, BV stimulation revealed a change of dominant conduction abnormalities with a delay of RV contraction in relation to LV (9.0 degrees +/- 17.5 v. -3.0 degrees +/- 11.4). CONCLUSIONS: Biventricular pacing results in slight improvement of LVEF in patients with heart failure and can be considered a promising approach in patients with end-stage heart failure. Synchronous stimulation of both ventricles not always results in decrease of interventricular shift, however that observation requires further studies on a larger population.