Technetium-99m-sestamibi scintigraphy: an alternative approach for diagnosis and follow-up of active myeloma lesions after high-dose chemotherapy and autologous stem cell transplantation.

Technetium-99m-sestamibi (MIBI) is a radionuclide tracer taken up by different malignant tumors. A total of 88 MIBI scans were carried out in 20 individuals with monoclonal gammopathy of unknown significance (MGUS) and 10 patients during follow-up for other cancers. Of these 58 MIBI scans were carried out in 46 myeloma patients: 15 at diagnosis, 14 during conventional chemotherapy, and 29 following high-dose sequential therapy and autologous peripheral blood progenitor support. A positive MIBI scan was exhibited by lof 10 with non-myeloma cancers and 2 of 20 with MGUS. In contrast, all stage II and III multiple myelomas (MM) were positive at diagnosis. Therefore, the sensitivity of the MIBI scan at diagnosis was 100%, whereas the specificity in this cohort was 93%. Four different MIBI patterns could be distinguished in MM patients: physiological, focal, diffuse, and extramedullary uptakes. In comparison to conventional skeletal radiographs, MIBI scans recognized a higher number of myeloma lesions at diagnosis. MIBI scans remained positive in all patients during conventional chemotherapy, and there was a direct correlation between MIBI result and clinical outcome of patients following high-dose therapy. Eighteen patients had a negative MIBI scan: 9 were in complete remission (CR), 8 in partial remission (PR), and 1 had progressive disease. Eleven patients showed lesions on the MIBI scan: 4 were in PR, 5 had progressive disease, 1 had a minimal response, and only 1 was in CR. A diffuse MIBI pattern reflected a higher bone marrow plasma cell number. In five patients, histologically or cytologically verified soft tissue myeloma lesions were correctly diagnosed by MIBI scan, while all plain radiographs showed none of them. MIBI has proven to be an effective tool in diagnosing biologically active myeloma.

[Planar myocardial scintigraphy with technetium-99m-sestamibi in acute myocardial infarct treated with thrombolytic therapy]. / La scintigrafia miocardica planare con tecnezio-99m-sestamibi nell'infarto miocardico acuto trattato con terapia trombolitica.

BACKGROUND: Nuclear cardiology permits the estimation of the myocardial infarction size and the result of the thrombolytic therapy. The aim of the study was to demonstrate the feasibility of the planar myocardial scintigraphy with Technetium-99-m-sestamibi in the coronary intensive care unit for the early identification of the infarct size and the result of the thrombolytic therapy. MATERIALS AND METHODS: We considered 10 patients affected by a first myocardial infarction (5 anterior and 5 inferior wall) then treated with thrombolytic therapy (APSAC 30 U. iv) within an interval of 3 hours from the onset of the symptoms. Technetium-99-m-sestamibi was injected before the thrombolytic therapy and the planar imaging was registered after 2-3 hours with a mobile gamma-camera. After 24 hours and before patient discharge we repeated the scintigraphic evaluation. Within 24 hours from the thrombolytic therapy the coronary angiography was performed for the demonstration of patency of the infarct-related artery. The left ventricle myocardial perfusion was divided in the 3 planar projections into 13 segments. The perfusion in each segment was evaluated with a perfusion score: 0 = normal perfusion, 1 = moderately reduced, 2 = severely reduced, 3 = absent. The sum of the hypoperfused segments represented the infarct size. A perfusion score improvement greater than 40% was considered a marker of reperfusion. RESULTS: The infarct size involved 4.4 +/- 1.4 segments in the anterior and 2 +/- 0.6 segments in the inferior wall infarctions (p < 0.05). The scintigraphic imaging made 24 hours after the myocardial infarction allowed the diagnosis of coronary reperfusion in 7 patients. The coronary angiography demonstrated the infarct related artery patency in 9 patients (all with TIMI perfusion score = 3). The nuclear imaging at patient discharge provided the diagnosis or reperfusion in 8 cases and demonstrated an improvement of the myocardial perfusion score in 5 cases. CONCLUSION: The scintigraphic imaging with Technetium-99-m-sestamibi in the patients with a myocardial infarction treated with thrombolytic therapy is feasible with a mobile gamma-camera in the intensive coronary care unit. The quality of planar imaging is good and allows the evaluation of myocardial infarct size and efficiency of thrombolytic therapy. An earlier scintigraphic imaging should be taken into consideration for a more timely non-invasive evaluation of patients who need coronary angiography and, if necessary, a rescue PTCA.

[Exercise 201-thallium myocardial scintigraphy in left bundle branch block]. / La scintigrafia miocardica da sforzo con 201-tallio in presenza di blocco di branca sinistra.

BACKGROUND: Reduced septal uptake of 201-Thallium in patients with left bundle branch block is reported in literature as having a variable frequency (between 14% and 100%) and in such patients the value of exercise Thallium-scintigraphy for the diagnosis of the left anterior descending coronary artery disease is limited by the great number of false-positive tests. The aim of this study was to assess the prevalence and the diagnostic sensitivity of this septal defect in a group of patients with left bundle branch block. METHODS: We evaluated the exercise 201-Thallium myocardial scintigraphy of 54 patients with a stable left bundle branch block. The clinical and/or echocardiographic evaluation excluded the presence of primitive, valvular and hypertensive cardiomyopathies and of previous myocardial infarction. The planar myocardial scintigraphic imaging was acquired according to the "stress-redistribution" protocol. Only 37 patients underwent an echocardiographic examination and following clinical and/or scintigraphic indications; 27 patients underwent a coronary angiography for the evaluation of coronary stenosis. RESULTS: The 201-Thallium imaging showed septal defects in 36 patients (67%) and the presence of defects in other segments in 14 patients. The echocardiographic evaluation showed an interventricular septal defect contraction abnormality in 19 cases in the 27 patients with septal defect and in 4 cases in the 10 patients with negative scintigraphy (Fisher NS). Twenty-seven patients (23 with- and 4 without septal defect) underwent a coronary angiography, which showed in 6 cases critical stenosis of the left descending anterior artery, in 5 of the right coronary, in 3 of the Circumflex artery and in 16 normal coronary angiograms. The presence of the septal uptake defect showed a diagnostic sensitivity and specificity for the detection of the left anterior descending coronary artery disease of respectively 67% and 52% (whereas using a semi-quantitative analysis of 100% and 19%). The scintigraphy showed a sensitivity and specificity for the detection of the right coronary artery disease of respectively 80% and 100% and for the circumflex coronary artery stenosis of 0% and 100%. CONCLUSIONS: We found a high prevalence of septal perfusion defects (67%) and this results shows a high sensitivity but a low specificity for the diagnosis of the left anterior descending coronary disease; the semi-quantitative analysis improves the sensitivity, but leads to a further reduction of the specificity. The female patients had a prevalence (70%) similar to the general population but demonstrated a higher percentage of false-positive. The 201-Thallium scintigraphy has a high diagnostic accuracy for the detection of the right coronary artery stenosis, while it is less accurate regarding the circumflex artery disease.

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

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

[The adenosine test in association with 99m-technetium sestamibi tomoscintigraphy in the diagnosis of coronary pathology]. / Il test all'adenosina associato alla tomoscintigrafia con 99m-tecnezio-sestamibi nella diagnosi di coronaropatia.

BACKGROUND: The exogenous adenosine is able to provoke a coronary vasodilation, which is the same as the one provoked by the papaverine and greater than the one provoked by the dipyridamole. We report our experience in using exogenous adenosine in association with technetium-99m-sestamibi tomoscintigraphy for a diagnostic test on the coronary artery disease (CAD). METHODS: We considered 22 patients (18 male and 4 female, mean age 57 years) affected by angiographically demonstrated coronary artery disease (stenoses > or = 50%). Adenosine was infused at a dosage of 0.070 mg/kg/min for 3 minutes and, if well tolerated, the dosage was increased to 0.140 mg/kg/min; in the third minute of the major dosage the radioisotope was injected. The myocardial perfusion imaging at rest was evaluated on the following day. RESULTS: The test was completed on 21 of the 22 patients, and 20 of the latter were subjected to the maximal dosage of the adenosine infusion. Clinically irrelevant adverse effects were observed in 20 cases; only one patient developed a II degree type 1 AV block. Angina occurred in 19 patients. Coronary angiography demonstrated significant stenosis of 35 vessels: the left anterior descending (LAD) in 14 patients, the left circumflex (LCx) in 8 and the right coronary artery (RCA) in 13. In detecting CAD, the test in our study demonstrated a sensitivity of 85% in the LAD disease, of 89% in the LCx disease and of 77% in RCA disease. CONCLUSIONS: The adenosine infusion associated with technetium-99m-sestamibi tomoscintigraphy demonstrated an elevated incidence of adverse effects which are of short duration and clinically irrelevant. The method was shown to be highly sensitive in detecting the CAD.