Pilot trial on determinants of progenitor cell recruitment to the infarcted human myocardium.

BACKGROUND: Clinical trials indicate a beneficial effect of intracoronary infusion of progenitor cells on myocardial function in patients with ischemic heart disease. The extent and potential determinants of proangiogenic progenitor cell homing into the damaged myocardium after intracoronary infusion and the underlying mechanisms are still unknown. METHOD AND RESULTS: Circulating proangiogenic progenitor cells isolated from peripheral blood and cultivated for 3 days were labeled with radioactive indium oxine ((111)In-oxine). Radiolabeled proangiogenic progenitor cells (7.6+/-3.0 MBq, mean+/-SD) were administered to patients with previous myocardial infarction and a revascularized infarct vessel at various stages after infarction (5 days to 17 years). Viability of the infarcted myocardium was determined by (18)F-fluorodeoxyglucose-positron emission tomography and microcirculatory function by intracoronary Doppler measurements. One hour after application of progenitor cells, a mean of 6.9+/-4.7% (range, 1% to 19%; n=17) of total radioactivity was detected in the heart, which declined to 2+/-1% after 3 to 4 days. Average activity within the first 24 hours was highest among patients with acute myocardial infarction (14 days to 1 year; 4.5+/-3.2%; n=4) or a chronic stage (infarct age >1 year; 2.5+/-1.6%; n=5). Low viability of the infarcted myocardium and reduced coronary flow reserve were significant (P<0.05) predictors of proangiogenic progenitor cell homing. CONCLUSIONS: In patients after myocardial infarction undergoing intracoronary infusion of (111)In-oxine-labeled proangiogenic progenitor cells, a substantial amount of radioactivity is detected for several days in the heart, indicating homing of progenitor cells to the myocardium. The amount of proangiogenic progenitor cells retained in the heart decreased progressively with time after the acute myocardial infarction. Proangiogenic progenitor cells preferentially home to extensive acute myocardial infarcts characterized by low viability and reduced coronary flow reserve.

The diagnostic role of radioactivity in sentinel nodes in oral and oropharyngeal cancer.

Sentinel lymph node biopsy (SNB), using radioactive tracers, is a novel, interesting tool in the staging of patients with oral and oropharyngeal squamous-cell carcinoma (OOSCC), which could lead to a reduced rate of elective neck dissections. The aim of the study was to evaluate the ranking of measured radioactivity in the sentinel lymph nodes (SLNs) and to correlate these findings with histopathological results to assess the number of SLN being sufficient for exact staging of the neck. In 77 consecutive patients with T1-4 OOSCC clinically and positron emission tomography-staged N0, between 15 and 55 MBq of Tc- 99m-labeled albumin-microcolloids were injected peritumorally and 213 SLNs were excised by small skin incisions using a gamma probe 2-3 hours later. The counts per second (cps) were measured ex vivo and excised SLNs were ranked according to their cps defining the LN with the highest activity as primary SLN, followed by a 2nd, 3rd, and so forth, SLN. Elective neck dissections were not performed. Median activity was 213 cps. All levels harbored SLNs with a maximum (43%) in level II and a minimum in level V (1%). SLNs in level II had significantly higher tracer accumulation (median, 289 cps) than those in levels I (144 cps) and IV (149 cps), but distant levels did not have significantly lower counts, compared to proximal. Eight (8) pathologically positive SLNs in 7 patients (7/77 = 9%; median activity, 157 cps) were detected. The median counts of the positive SLNs were not significantly different from those of the 205 negative SLNs (235 cps). The positive SLN was the one with the highest tracer accumulation in 4 cases, with the second highest in 1 case, and with the third highest tracer accumulation in 2 cases. Three (3) positive SLN were in level IB, 4 in level IIA, and 1 in level III. One (1) patient had 2 positive SLNs: a SLN with the third highest activity in level IIB and a SLN with the fifth highest activity in level III. In OOSCC, excision of only 1 SLN is not feasible. The positive SLNs were not necessarily the hottest nodes. Utilizing radiotracer lymphatic mapping, the 3 SLNs with the highest activity should be excised for exact staging of the neck in patients with T1-3 tumors. Excision of all radioactive nodes is recommended until further studies will prove this result. Large T4a tumors should not be staged using SNB.

Transplantation of Progenitor Cells and Regeneration Enhancement in Acute Myocardial Infarction (TOPCARE-AMI).

BACKGROUND: Experimental studies suggest that transplantation of blood-derived or bone marrow-derived progenitor cells beneficially affects postinfarction remodeling. The safety and feasibility of autologous progenitor cell transplantation in patients with ischemic heart disease is unknown. METHODS AND RESULTS: We randomly allocated 20 patients with reperfused acute myocardial infarction (AMI) to receive intracoronary infusion of either bone marrow-derived (n=9) or circulating blood-derived progenitor cells (n=11) into the infarct artery 4.3+/-1.5 days after AMI. Transplantation of progenitor cells was associated with a significant increase in global left ventricular ejection fraction from 51.6+/-9.6% to 60.1+/-8.6% (P=0.003), improved regional wall motion in the infarct zone (-1.5+/-0.2 to -0.5+/-0.7 SD/chord; P<0.001), and profoundly reduced end-systolic left ventricular volumes (56.1+/-20 mL to 42.2+/-15.1 mL; P=0.01) at 4-month follow-up. In contrast, in a nonrandomized matched reference group, left ventricular ejection fraction only slightly increased from 51+/-10% to 53.5+/-7.9%, and end-systolic volumes remained unchanged. Echocardiography revealed a profound enhancement of regional contractile function (wall motion score index 1.4+/-0.2 at baseline versus 1.19+/-0.2 at follow-up; P<0.001). At 4 months, coronary blood flow reserve was significantly (P<0.001) increased in the infarct artery. Quantitative F-18-fluorodeoxyglucose-positron emission tomography analysis revealed a significant (P<0.01) increase in myocardial viability in the infarct zone. There were no differences for any measured parameter between blood-derived or bone marrow-derived progenitor cells. No signs of an inflammatory response or malignant arrhythmias were observed. CONCLUSIONS: In patients with AMI, intracoronary infusion of autologous progenitor cells appears to be feasible and safe and may beneficially affect postinfarction remodeling processes.

Positron emission tomography in combination with sentinel node biopsy reduces the rate of elective neck dissections in the treatment of oral and oropharyngeal cancer.

PURPOSE: To assess the impact of a diagnostic ladder including [(18)F]fluorodeoxyglucose positron emission tomography (PET) and lymphoscintigraphy guided sentinel node biopsy (LS/SNB) on neck treatment in patients with oral and oropharyngeal squamous cell carcinoma (OOSCC). PATIENTS AND METHODS: Prospectively, 62 patients with resectable T1-3 OOSCC underwent computed tomography (CT) and PET. Patients without neck uptake in PET were defined as cN0 and were accrued for LS/SNB. Results were correlated with histopathology. The traditional guidelines according to CT findings were compared to the actual regimen and the outcome. RESULTS: Sensitivity, specificity, validity, and positive and negative predictive value of PET versus CT were 72% v 89%, 82% v 77%, 79% v 80.5%, 62% v 61.5%, and 88% v 94.5% (not significant). Thirty-eight PET negative patients underwent LS/SNB. Sentinel lymph nodes were found in all 38 patients. Five patients had positive nodes (PET false-negatives) and underwent neck dissection (ND). Fifty-one neck sides in 36 patients who were CT-negative would have been treated with selective ND according to the guidelines, and at least 45 neck sides would have had to undergo extensive ND because of positive CT findings (96 of 124 neck sides). In contrast, PET in combination with LS/SNB spared 59 neck sides, and 41 of 124 neck sides actually underwent ND as a result of PET staging, LS/SNB, and intraoperative decision. After a median follow-up of 35 months, two patients (both cN+ve and pN+ve) suffered from neck relapses. CONCLUSION: Diagnostics using PET in combination with LS/SNB considerably reduced the number of extensive ND in OOSCC as compared to CT without locoregional hazard.

rhTSH stimulation before radioiodine therapy in thyroid cancer reduces the effective half-life of (131)I.

UNLABELLED: Recombinant human thyroid-stimulating hormone (rhTSH) is effectively used for exogenous thyroid-stimulating hormone (TSH) stimulation before diagnostic (131)I scintigraphy. It is not yet widely used for preparation of patients receiving a therapeutic amount of radioiodine. METHODS: The results of 64 consecutive therapeutic applications of rhTSH with regard to clinical tolerance and side effects were evaluated in comparison with 163 radioiodine therapies (RITs) done on patients with hypothyroidism after thyroxine withdrawal during the same period. All therapies-applying 1.1-10 GBq of (131)I-used a standardized protocol of patient preparation and activity application. RITs were followed by daily whole-body uptake measurements for 2-6 d, and a biexponential curve fit was used to obtain a short initial and afterward a long effective half-life of (131)I. Patients after rhTSH were evaluated as a whole group (group A, n = 64) and as a subset of that group with normal thyroglobulin (hTG) levels (group D, n = 18). Patients after endogenous TSH stimulation were evaluated as a whole group (group B, n = 163), as a subset of that group excluding all ablative RITs (group C, n = 113), and as a subset of that subset with normal hTG levels (group E, n = 87). RESULTS: rhTSH-stimulated patients showed significantly higher TSH values than did endogenously stimulated patients (P < 0.001). Furthermore, the effective half-life of (131)I was significantly prolonged after endogenous stimulation (e.g., 0.43 d for group A vs. 0. 54 d for group B, P < 0.001). All rhTSH applications were tolerated well and without serious side effects. The only side effects were 2 cases of nausea and headache. CONCLUSION: The use of rhTSH for stimulation of TSH before RIT is safe but also significantly reduces the effective half-life of (131)I. This is mainly due to a reduced renal iodine clearance in the hypothyroid state, but the bioavailability of radioiodine may be slightly overestimated because of larger amounts of intestinal (131)I after endogenous TSH stimulation.

Differentiated thyroid carcinoma: the new UICC 6th edition TNM classification system in a retrospective analysis of 169 patients.

AIM: To compare the new, 6th edition, UICC TNM staging system with the former edition, we updated TNM staging in patients with differentiated thyroid carcinoma. METHODS: The new and old TNM classification systems for differentiated thyroid carcinoma were applied in a retrospective analysis of 169 patients who underwent therapy with radioiodine (131I) from 1975 through 2002 at the Department of Nuclear Medicine, Frankfurt. RESULTS: According to the new staging system, 83 patients (49%) were classified as T1 compared to 54 patients (32%) based on the former edition; 32 patients (19%) as T2 compared to 61 (36%) patients formerly. In 44 patients with minimal extrathyroid extension, formerly classified T4, the new TNM staging changed to T3, and no patient was classified T4. The one year relapse-free survival fraction under the former edition staging was 100% for T1 and 92.2% for T2, compared to 96.8% for new edition T1 and 93.3% for T2. CONCLUSION: The new TNM classification causes a significant change in staging. New T1 classified tumors had a slightly worse relapse-free survival fraction compared with the old T1 carcinomas. For patients treated at our department, the altered criteria for classifying extrathyroid extensions have had only a minor impact on disease management.

PET imaging of Rosai-Dorfman disease: correlation with histopathology and ex-vivo beta-imaging.

We report the case of a woman who developed an early relapse of a squamous cell carcinoma (SCC) and was thus restaged twice within a year using [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET). While there was no evidence of metastatic tumor outspread, focally increased FDG uptake was visible in numerous nodes but showed no change during the period between the two PET scans. These nodes, predominantly located at the proximal extremities, ranged in size from about 1 cm to over 6 cm. They were located subcutaneously, showed a red/bluish livid color and were of stout consistency. These nodes occurred first after radiochemotherapy for a non-Hodgkin's lymphoma (NHL) about 6 years earlier and slowly increased in size and number. One node of the right forearm was resected and ex-vivo beta-imaging, directly measuring the positron emission of the intranodal FDG distribution, was done and showed an overall increased glucose utilization with distinct spots of high metabolism. Histopathological work-up of the tumor showed widespread granulomatous tissue with lymphocyte follicles. Immunostaining showed the tumor to be positive for S100, CD68 and vimentin. Rosai-Dorfman disease (RDD) was diagnosed and no evidence of a potential relapse of the previous NHL was detected. RDD is a rare disease that is associated with the multifocal growth of benign tumors. The lesions are metabolically highly active. The correlation of the beta-imaging and histopathological results showed a high metabolism within granulomatous tissue with more intense metabolism within lymphocyte follicles.

Positron emission tomography in patients with Hodgkin's disease: correlation to histopathologic subtypes.

The aim of this study was to evaluate the initial staging and restaging of Hodgkin's disease (HD) according to histopathologic subtype (HST) using fluorine-18-deoxyglucose-positron emission tomography (PET). Special attention was paid to the accuracy of PET for detection of bone marrow infiltration (BMI). 44 patients with HD (m:f = 28:16, mean age 36 +/- 15 years) underwent PET; 16 were primary stagings and 28 restaging examinations. PET results were compared with methods of conventional staging including computed tomography (CT) and bone marrow biopsy. Viable tumor tissue was detected by PET in 25/44 cases, 16 nodular sclerosis (NS), 4 mixed cellularity (MC), 3 lymphocyte predominance (LP) and 2 cases with a nonclassified subtype (NC). FDG tumor uptake, measured as standard uptake value (SUV), ranged from 1.7 to 13. Maximum SUV in NS was 5.2 +/- 1.5 (2.5-7.3), 3.2 +/- 2.4 for MC, 2.6 +/- 0.7 for LP, and 9.1 +/- 3.8 for NC, respectively. In 7% of all patients (3/44) bone marrow infiltrations were detected by PET. PET is known for its superior detection of viable tissue in HD. In this study it was shown that HST does not influence the intensity of glucose metabolism, although 2 patients with NC showed the highest SUVs. In addition PET accurately detected focal BMI and may thus be applied before BMB to guide its optimal use.

Enchondroma: a benign osseous lesion with high F-18 FDG uptake.

A woman was referred for fluorodeoxyglucose positron emission tomography for the staging of a malignant melanoma. Although no signs of metastatic melanoma were evident on the whole-body scan, focally increased uptake within the femoral metaphysis was noted. Radiographic and magnetic resonance examinations revealed an enchondroma as the cause of the increased uptake. Histopathologic verification was obtained. The final diagnosis was actively proliferating enchondroma. A grade I chondrosarcoma could be ruled out. Enchondromas may be responsible for focally increased FDG uptake in bone lesions and must be considered when positron emission tomographic scans obtained with FDG are evaluated in cancer staging.

Re-186 HEDP conditioning therapy in patients with advanced acute lymphoblastic leukemia before allogeneic bone marrow transplantation.

The authors present their experience with dose calculation of Retin1,1-hydroxyethylidene-186-diphosphonate (Re-186 HEDP) therapy used as part of an intensified conditioning regimen before allogeneic stem cell transplantation in 2 patients with advanced acute lymphoblastic leukemia during the second partial or third complete remission. Kidneys were shielded during total-body irradiation (TBI) to limit the TBI-mediated renal radiation dose to 7 Gy. The aim of this dose calculation of Re-186 HEDP therapy was to deliver additional radiotherapy to the red bone marrow without exposing more than an additional 5 Gy to the kidneys in addition to the TBI standard dose of 12.6 Gy. Pretherapeutic kidney scintigraphy (Tc-99m mercaptoacetyltriglycine) showed normal results. Thus, dynamic Tc-99m methylene diphosphonate bone scintigraphy was used to calculate the expected bone marrow and kidney doses. A total amount of 8.8 GBq (238 mCi) Re-186 HEDP was given to patient no. 1 and 14.3 GBq (387 mCi) Re-186 HEDP was given to patient no. 2. Re-186 HEDP activity was monitored based on its gamma radiation measurement daily for 5 days in patient no. 1 and 7 days in patient no. 2. Therapeutic Re-186 isotope distribution and biologic half-life correlated well with the prediction by a pretherapeutic Tc-99m methylene diphosphonate scan. The calculated effective Re-186 bone marrow dose was 3.3 Gy for patient no. 1 and 5.6 Gy for patient no. 2. Effective kidney doses were 1.6 Gy and 2.1 Gy respectively. No unexpected complications occurred after completing conditioning and allogeneic stem cell transplantation. Posttransplant kidney function remained normal. Patient no. 1 remains in a second complete remission of his advanced acute lymphoblastic leukemia 18 months after HEDP therapy. Patient no. 2 relapsed 5 months after transplantation and eventually died as a result of progressive disease. The authors conclude that Re-186 HEDP will be able to increase the total additional bone marrow dose. In patients in whom the kidney dose is limited to 5 Gy in addition to TBI, doses near 10 Gy can be achieved on the bone marrow.

Pattern of drainage in sentinel lymph nodes after intra-arterial chemotherapy for oral and oropharyngeal cancer.

PURPOSE: Prerequisite for lymphoscintigraphy-guided sentinel lymph node (SLN) biopsy in head and neck cancer patients has been a previously untreated primary tumor to avoid disturbance of the lymphatic flow. We evaluated the feasibility in a multimodality treatment approach to oral and oropharyngeal cancer comprising presurgical intra-arterial chemotherapy of the primary tumor. PATIENTS AND METHODS: In a prospective study of 35 consecutive patients with primary oral and anterior oropharyngeal cancer T1-4N0 treated with superselective intra-arterial chemotherapy with high-dose cisplatin, SLN scintigraphy was performed on the day of surgery, including gamma camera imaging before and hand-held gamma probe identification of the SLN during surgery. SLN biopsy was performed in 50 neck sides, followed by radical resection of the primary in the same session. Elective neck dissection was not carried out. The pattern of lymphatic drainage was recorded and compared with the literature on well-known patterns found in lymphographic studies and metastatic disease in neck dissection specimens of patients without presurgical treatment. RESULTS: Drainage patterns of SLN related to different primary locations mapped the mentioned comparison patterns. SLN drainage patterns gave strong evidence that there are SLN in levels 3 and 4 with direct drainage from the primary. After a median observation time of 24 months, no patients had a neck relapse. CONCLUSIONS: The results suggest that intra-arterial chemotherapy of the primary tumor does not significantly alter lymphatic drainage and that SLN biopsy following intra-arterial chemotherapy is feasible and offers valid results comparable to those obtained from patients without presurgical treatment.

Diagnostic value of FDG-PET and HMPAO-SPET in patients with mild dementia and mild cognitive impairment: metabolic index and perfusion index.

OBJECTIVE: The diagnostic potential of F-18-2-fluoro-2-deoxy-D-glucose positron emission tomography (PET) and technetium-99m hexamethylpropylene amine oxime single-photon emission tomography (SPET) in early detection and differential diagnosis of early dementia was evaluated including a comparison of metabolic and perfusion indices (PI). METHODS: Twenty-four patients with initial clinical suspicion of beginning dementia were examined, 12 of them with mild cognitive impairment. All patients underwent SPET and PET within 2 weeks. Data were compared with the final clinical diagnosis at follow-up - 9 with Alzheimer's disease (AD), 1 with frontotemporal dementia, 1 with vascular dementia (VD), 7 with mixed type of dementia (MIX) and 6 without any type of dementia. Metabolic indices (MI) and PI were compared with each other. The regional cerebral blood flow difference (rCBFdiff) calculated as local uptake difference between the right and left hemisphere was measured for patients with VD and MIX. RESULTS: PET showed higher sensitivity and specificity in identifying the different types of early dementia (44--91 and 78--89%, respectively) than SPET (11--64 and 79--89%, respectively), especially in detecting AD (sensitivity 44%, specificity 83%) and MIX (sensitivity 71%, specificity 78%). Especially in patients with mild cognitive impairment, PET was the superior imaging modality for predicting dementia. Using PET, dementia could be excluded in all patients who did not develop dementia during the follow-up. In all patients, a weak correlation between PI and MI was observed (rho=0.64, p<0.002). The rCBFdiff in patients with VD and MIX ranged from 7 to 37%. CONCLUSION: In this study on patients with initial suspicion of beginning dementia who underwent both imaging modalities, PET and SPET, PET was the superior imaging method, especially in the detection of early AD or MIX.

Urinary fluorine-18 fluorodeoxyglucose excretion with and without intravenous application of furosemide.

METHODS: Twenty patients suffering from malignancy received furosemide, twenty patients were examined by FDG-PET without diuretics. Urine volume and radioactivity were measured before and after acquisition. Bladder activity was evaluated qualitatively and quantitatively. RESULTS: Radioactivity in the bladder was lower and the image quality higher in the furosemide group. SUV values showed a median of 3.0 in the furosemide and 6.0 in the control group. With furosemide, a larger excreted volume was seen compared to the control group. The furosemide group showed a significantly higher ratio of excreted/ injected radioactivity early after injection. However, the totally excreted radioactivity was not significantly different (p = 0.93). CONCLUSION: Diuretics cause a higher urine volume with a diluted FDG concentration leading to an improved image quality. Furosemide accelerates early renal FDG elimination, reducing radiation exposure.

Positron emission tomography for the staging of Hodgkin's lymphoma--increasing the body of evidence in favor of the method.

The staging of Hodgkin's lymphoma (HL) is crucial for an optimal therapy, and fluorine-18-deoxyglucose-positron emission tomography (FDG-PET) is increasingly used in this regard. However, there is still a scarcity of available data on the staging of HL. Twenty-eight consecutive patients with newly diagnosed HL were included in this study. PET results were compared with conventional staging, including clinical workup, computerized tomography (CT) and sonography. Evaluation was focused on the description of involved lymph node (LN) regions or organs rather than on a lesion-by-lesion analysis. In supradiaphragmal LN, the results of PET and CT scans were positive in 26% and negative in 68% of cases. Furthermore, PET was positive in 5% (CT negative), and CT showed enlarged LN in 1% of cases (PET negative). In infradiaphragmal LN, PET/CT results were positive in 10% and negative in 88% of cases. In 2% of cases, PET showed additional foci, while in 1% the CT was positive. PET changed the staging in 21% of cases (4 up-stagings, 2 down-stagings) and this was confirmed during follow-up. PET should therefore be routinely used for staging HL until larger clinical studies can demonstrate patients who may not require this additional investigation or those patients who are reliably staged on the basis of PET alone.

The influence of CA 125 and CEA levels on the results of (18)F-deoxyglucose positron emission tomography in suspected recurrence of epithelial ovarian cancer.

BACKGROUND AND PURPOSE: The follow-up of epithelial ovarian cancer (OCA) consists of clinical investigation, sonography, and tumor markers (TMs), especially CA 125. If tumor recurrence is suspected, other imaging modalities including positron emission tomography (PET) with (18)F-deoxyglucose (FDG) are often used. While there is still no consensus about the method of choice and the timing of its application, this study aims to find a TM threshold at which a PET would be appropriate. MATERIAL AND METHODS: A total of 90 PET studies and the associated CA 125 values (normal value < 35 U/ml) were available in 71 patients during the follow-up after primary therapy for OCA. In 48 studies a CEA value (normal value < 3 ng/ml) was also available. The results of PET imaging were related to the level of TM increase. RESULTS: In 23/90 studies the PET scan was normal. These patients had a median CA 125 of 13.3 U/ml (range 4.2-168 U/ml). In 67/90 studies the PET indicated a potential recurrence of OCA and the median CA 125 was 166.7 U/ml (range 13.3-4,060 U/ml). The TM levels were significantly different (p < 0.001, U-test). With one exception, there were no normal PET scans above CA 125 levels of 30 U/ml; between 20 and 30 U/ml PET was positive in 4/7 studies. CONCLUSION: In suspected recurrence of OCA, if imaging modalities are to be used, an FDG PET may be considered. Since the costs of this investigation are high, it should be restricted to clinical situations where it is likely to be most effective. In this study a PET indication is worthwhile at CA 125 levels of approximately 30 U/ml.

Transplantation of progenitor cells after reperfused acute myocardial infarction: evaluation of perfusion and myocardial viability with FDG-PET and thallium SPECT.

Clinical outcome after myocardial infarction depends on the extent of irreversibly damaged myocardium. Implantation of bone marrow-/circulating blood-derived progenitor cells has been shown to improve contractile cardiac function after myocardial infarction in both experimental and initial clinical studies. In the present study, first observations of the effect of local intracoronary progenitor cell infusion on the regeneration of infarcted cardiac tissue after acute myocardial infarction was evaluated by means of 18F-fluorodeoxyglucose positron emission tomography (PET) and 201Tl single-photon emission computed tomography (SPECT). Twenty-six patients underwent intracoronary infusion of bone marrow-derived (BMCs) (15 patients) or circulating blood-derived endothelial progenitor cells (EPCs) (11 patients) 4+/-2 days after acute myocardial infarction. Based on a left ventricular segmentation model (17 segments), mean signal intensities as a parameter of viability and perfusion in the infarct zone and non-infarct areas were calculated quantitatively by PET and SPECT at baseline and at 4 months of follow-up. Transplantation of progenitor cells was associated with a significant increase in the mean signal intensity (MSI) in the infarct zone from 54.5% (25th and 75th percentiles: 47.7%, 60.0%) to 58.0% (52.7%, 66.7%) on PET (P=0.013) and from 58.0% (49.5%, 63.0%) to 61.5% (52.5%, 70.2%) on SPECT (P=0.005). Global left ventricular ejection fraction (LVEF) increased from 53.5% (42.6%, 60.0%) to 58.0% (53.0%, 65.8%) (P<0.001). In the five patients without an increase in MSI on PET, LVEF changed from 60.0% (50.0%, 64.0%) to 72.0% (64.0%, 75.5%) at follow-up. PET and SPECT did not show any significant changes in MSI in the non-infarct areas [from 73% (68.5%, 76.2%) to 73% (69.7%, 78.0%) for PET and from 72.0% (66.5%, 77.6%) to 73.0% (67.5%, 78.2%) for SPECT]. There were no significant differences in myocardial viability and perfusion between BMC and EPC infusion. These preliminary results show that coronary stenting and transplantation of progenitor cells result in a significant increase in myocardial viability and perfusion. Therapeutic effects can be reliably measured by PET and SPECT.