Advantages of positron emission tomography (PET) with respect to computed tomography in the follow-up of lymphoma patients with abdominal presentation.

For abdominal lymphoma patients, fluorine-18 fluorodeoxyglucose positron emission tomography (PET) provides unique information on the presence of residual active disease. We provide an update on the largest reported cohort of patients whose management following induction therapy was based on routine PET and computed tomography (CT) restaging. Fifty-nine patients with Hodgkin's disease or aggressive non-Hodgkin's lymphoma presenting abdominal involvement (35% with bulky disease) were studied with both PET and CT following combined chemotherapy/radiation treatment. After treatment, 3/3 (100%) patients who were PET+/CT- relapsed, compared with 0/7 patients in the PET-/CT- subset. Among the 49 patients who were CT+, six of the 10 (60%) who were PET+ relapsed, as compared with only two of the 39 (5%) who were PET-. The actuarial relapse-free survival (RFS) rates were 0 and 100% in the PET+/CT- and PET-/CT- subsets, respectively. In the PET+/CT+ subset, RFS was 94% at 5 years. PET restaging is very valuable for the identification of patients who would need appropriate second-line therapy because of the presence of residual active abdominal disease and should be made widely available in combination with CT.

Value of 18-fluorodeoxyglucose positron emission tomography in the management of patients with cystic tumors of the pancreas.

OBJECTIVE: To assess the reliability of 18-fluorodeoxyglucose positron emission tomography (18-FDG PET) in distinguishing benign from malignant cystic lesions of the pancreas. SUMMARY BACKGROUND DATA: The preoperative differential diagnosis of cystic lesions of the pancreas remains difficult: the most important point is to identify malignant or premalignant cysts that require resection. 18-FDG PET is a new imaging procedure based on the increased glucose metabolism by tumor cells and has been proposed for the diagnosis and staging of pancreatic cancer. METHODS: During a 4-year period, 56 patients with a suspected cystic tumor of the pancreas underwent 18-FDG PET in addition to computed tomography scanning, serum CA 19-9 assay, and in some instances magnetic resonance imaging or endoscopic retrograde cholangiopancreatography. The 18-FDG PET was analyzed visually and semiquantitatively using the standard uptake value. The accuracy of 18-FDG PET and computed tomography was determined for preoperative diagnosis of a malignant cyst. RESULTS: Seventeen patients had malignant tumors. Sixteen patients (94%) showed 18-FDG uptake with a standard uptake value of 2.6 to 12.0. Twelve patients (70%) were correctly identified as having malignancy by computed tomography, CA 19-9 assay, or both. Thirty-nine patients had benign tumors: only one mucinous cystadenoma showed increased 18-FDG uptake (standard uptake value 2.6). Five patients with benign cysts showed computed tomography findings of malignancy. Sensitivity, specificity, and positive and negative predictive values for 18-FDG PET and computed tomography scanning in detecting malignant tumors were 94%, 97%, 94%, and 97% and 65%, 87%, 69%, and 85%, respectively. CONCLUSIONS: 18-FDG PET is more accurate than computed tomography in identifying malignant pancreatic cystic lesions and should be used, in combination with computed tomography and tumor markers assay, in the preoperative evaluation of patients with pancreatic cystic lesions. A positive result on 18-FDG PET strongly suggests malignancy and, therefore, a need for resection; a negative result shows a benign tumor that may be treated with limited resection or, in selected high-risk patients, with biopsy, follow-up, or both.

Cerebral perfusion in hypertensives with carotid artery stenosis: a comparative study of lacidipine and hydrochlorothiazide.

Focal cerebral hypoperfusion is a common finding in uncomplicated hypertensives even in the absence of large vessel atherosclerosis, and neuropsychological deficits correlate with cerebral hypoperfusion in hypertensive patients with cerebral microangiopathy. We investigated the effects on cerebral perfusion of the dihydropiridine calcium antagonist lacidipine and of hydrochlorothiazide (HCTZ) in asymptomatic hypertensive patients with concomitant atherosclerosis of the carotid arteries. Fifteen essential hypertensives (including 13 males, aged 55-75 years) with at least one 30-60% stenosis of the internal carotid artery at echo-color Doppler examination were treated in a double-blind, randomized, parallel study with lacidipine (4-6 mg od) or HCTZ (25-50 mg od) for 3 months after a 4-week single-blind placebo period. Regional cerebral perfusion was assessed at baseline and at the end of the treatment period with HMPAO-SPECT. Relative perfusion of cortical and subcortical areas was calculated as the ratio between their tracer activity and that of the cerebellum. At baseline, mean relative perfusion (MRP) of the cortical and subcortical areas was similar in the stenotic and the contralateral side. Despite the fall in pressure, lacidipine increased MRP both in the cortical and in the subcortical areas, whereas HCTZ increased MRP only in the cortical areas. The mean change in local vascular resistance, adjusted for initial perfusion value, was -20 A.U. (arbitrary unit) with lacidipine and -12 A.U. with HCTZ (p < 0.001). These differential effects of antihypertensive drugs on subcortical perfusion may be of benefit in the long-term prevention of vascular dementia in hypertensive patients.

Effects of left bundle branch block on myocardial FDG PET in patients without significant coronary artery stenoses.

UNLABELLED: Cardiac PET studies in patients with left bundle branch block (LBBB) are few, and the results are conflicting. In particular, even if a reduced uptake of FDG is reported, confirmation in a large group of patients and exact understanding of the underlying cause are lacking. METHODS: We selected 29 consecutive patients who had complete LBBB and no significant stenosis on coronary angiography scheduled for FDG and 13N-NH3 PET for myocardial viability evaluation at our center. Wall motion was evaluated using 2-dimensional echocardiography. Ten volunteers without coronary stenosis or LBBB served as a control group. RESULTS: All LBBB patients had a reverse mismatch in the septum, defined as reduced uptake of FDG in comparison with 13N-NH3. The mismatch extended to the anterior and inferior walls in 17 patients. The mean (+/-SD) septal-to-lateral ratio was 0.57 +/- 0.11 for FDG (range, 0.28-0.76) and 0.99 +/- 0.12 for 13N-NH3 (range, 0.75-1.18), with P < 0.0001. In contrast, no significant differences in uptake were seen in the control group, which had a septal-to-lateral ratio of 0.95 +/- 0.13 for FDG (range, 0.78-1.15; P < 0.01 with respect to LBBB patients) and 0.94 +/- 0.11 (range, 0.85-1.20) for 13N-NH3. CONCLUSION: Our study suggests that in LBBB patients without significant coronary stenosis, FDG uptake in the septum changes without a correlating change in perfusion. To avoid possible overestimation of necrosis, especially in the LAD territory, this phenomenon must be considered in evaluations of myocardial viability using FDG images.

Cerebral perfusion in hypertensive patients: effects of lacidipine and hydrochlorothiazide.

Previous studies have shown areas of cerebral hypoperfusion in the frontal and parietal lobes of asymptomatic hypertensives, in the absence of extracranial carotid artery stenosis. The aims of the present study were: (a) to correlate the presence of focal cortical hypoperfusion with the presence of white matter lesions (WML), lacunae and extracranial carotid artery stenosis; and (b) to compare the effects on cerebral perfusion of the dihydropyridine calcium entry blocker lacidipine and of hydrochlorothiazide (HCTZ) in hypertensive patients with carotid artery stenosis. Forty-one patients (30 males, aged 40-75) with mild to moderate essential hypertension and with negative history for cerebrovascular diseases were investigated. Twenty-four had normal extracranial carotid arteries at echo-colourDoppler examination, while 17 had at least one 50-70% stenosis of the internal carotid artery (ICA). At computed tomography (CT) scan, five patients had one or more lacunar infarctions, four WML, three lacunar infarctions and WML, and 26 a normal CT scan. Three, with old cortical infarctions, were excluded from further analysis. The prevalence of lesions was significantly higher among the patients with carotid artery stenosis (44% vs. 29%; p < 0.05). Distribution of mean relative cortical perfusion (MRCP) of regions of interest [hexamethyl-propileneamine oxime-single photon emission tomography (SPET)] was not normal, with a negative skewness in patients with lacunae. MRCP was slightly but significantly reduced in patients with lacunae in comparison with hypertensives with normal CT scan and with WML. The asymmetry index of tracer distribution was significantly greater in the patients with lacunar infarctions and WML than in the hypertensive patients with normal CT scan, irrespective of the presence of internal carotid artery stenosis. Fifteen hypertensives (13 males, aged 55-75 years) with at least one moderate stenosis of ICA at duplex scanning were treated in a double-blind, randomised, parallel study with lacidipine (4-6 mg o.d.) or HCTZ (25-50 mg o.d.) for 3 months after a 4-week single-blind placebo period. At baseline, perfusion of the cortical and basal areas was similar in the stenotic and the contralateral side. Despite the fall in pressure, both treatments increased MRCP in the stenotic side and in the contralateral side. The lower the baseline perfusion, the larger its increase with treatment. The decrease of local cerebral vascular resistance was significantly greater with lacidipine than with HCTZ. We conclude that in hypertensive patients, the distribution of cerebral flow is uneven, mostly in the presence of small asymptomatic subcortical lesions and independently from internal carotid artery stenosis. Antihypertensive treatment with lacidipine and HCTZ reduces local cerebral resistance and corrects focal hypoperfusion without inducing steal effects in patients with ICA stenosis.

The role of positron emission tomography (PET) in the management of lymphoma patients.

BACKGROUND: Treatment of both Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL) with abdominal presentation at the time of diagnosis is often followed by detection of residual masses by computed tomography (CT). However, CT is usually unable to discriminate between residual tumor and fibrosis/necrosis. We investigated the ability of fluorine-18 fluorodeoxyglucose positron emission tomography (PET) to differentiate between residual active tumor tissue and fibrosis. PATIENTS AND METHODS: Forty-four patients with HD or aggressive NHL presenting abdominal involvement (41% with bulky mass) were studied with CT and PET at the end of chemotherapy +/- radiation therapy. RESULTS: After treatment, seven patients had negative PET and CT, and none of them relapsed. The remaining 37 patients all had positive CT (abnormalities < or = 10%). All of the 13 who also had positive PET relapsed (100%). By contrast, there was only 1 (4%) relapse among the 24 patients who were positive at CT but negative at PET. The two-year actuarial relapse-free survival rate was 95% for those with negative PET compared with 0% for positive PET patients (P < 0.000000). CONCLUSIONS: In lymphoma patients with abdominal masses who present CT positivity at restaging, PET should be considered the noninvasive imaging modality of choice for differentiating early recurrences or residual disease from fibrosis.

PET supports the hypothesized existence of a male sexual brain algorithm that may respond to treatment combining psychotherapy with virtual reality.

Could a brain circuit exist, verifiable using positron emission tomography (PET), that links coitus and its dysfunctions, such as impotence? Could re-establishing normal sexual functioning be linked with the normalization of some sort of altered brain metabolism utilizing a therapeutic project that uses psychodynamic psychotherapy integrating virtual reality (VR)? A Brain PET Scan and a self-administered sexual activity questionnaire were given to 11 heterosexual patients affected by impotence due to psychological causes, both before and approximately 6 months after a cycle of psychodynamic psychotherapy. Seven randomly-selected patients received psychotherapy with VR technology using the Optale Method. PET data, used to indicate glucose consumption in various brain areas, were compared with data from normal patients, and a statistical analysis was run. Alterations in cerebral metabolic functioning were displayed in the following areas: frontal cortex, nucleus caudatus, and thalamus. The seven patients who received psychotherapy with VR technology "normalized" in these same areas and attained satisfactory sexual performance. The existence of a male sex algorithm may be hypothesized that links the frontal cortex, nucleus caudatus, and thalamus, and explains its action on cortical motor areas and/or on the medial preoptic area of the hypothalamus, which may respond to treatment combining psychotherapy with VR.

[Effects of spinal cord stimulation on regional myocardial blood flow in patients with refractory angina. A positron emission tomography study]. / Effetti della stimolazione spinale epidurale sul flusso miocardico regionale in pazienti con angina pectoris refrattaria. Uno studio con tomografia ad emissione di positroni.

BACKGROUND: Spinal cord stimulation (SCS) is an alternative therapy in patients with refractory angina pectoris when coronary revascularization cannot be performed. Several hypotheses have been given to explain the effects of SCS in reducing the number and the intensity of anginal crises. These hypotheses include possible variations in myocardial blood flow (MBF). The aim of our study was to assess regional MBF in a group of patients with spinal cord stimulator, using positron emission tomography (PET). METHODS: We studied 15 patients (9 male and 6 female), mean age 74 +/- 7 years, who were carriers of a spinal cord stimulator implanted 17 +/- 14 (range 1-48) months before. All patients had been affected with angina pectoris that was refractory to maximal tolerated pharmacological therapy. Eight patients had had a previous myocardial infarction and four patients had undergone a revascularization procedure. Every patient underwent two PETs with nitrogen-13-ammonia as the perfusion tracer. The first one was performed with the stimulator switched off for at least 20 hours, and the second one with the stimulator switched on for at least 4 hours. The quantitative evaluation of regional MBF (anterior, inferior, lateral, septal walls and apex) was performed with Patlak graphic analysis. The normal value of basal MBF in our laboratory is 0.6-1 ml/min/g. RESULTS: The mean value of MBF increased from 0.72 +/- 0.33 ml/min/g with the stimulator off, to 0.80 +/- 0.33 ml/min/g with it on (p = 0.004). An increase in regional myocardial perfusion, with the stimulator on as opposed to off, was observed in 47 (62%) of the 75 regions studied. With the stimulator on, in comparison with off, the value of MBF increased from 0.45 +/- 0.11 ml/min/g to 0.56 +/- 0.19 (p = 0.0001) in the 35 regions with low basal MBF (< 0.6 ml/min/g), and from 0.77 +/- 0.14 ml/min/g to 0.92 +/- 0.29 ml/min/g (p = 0.013) in the 23 regions with basal MBF between 0.6 and 1 ml/min/g. Instead, in the 17 regions with high basal MBF (> 1 ml/min/g) it decreased with the stimulator on instead of off, going from 1.22 +/- 0.20 to 1.13 +/- 0.22 ml/min/g (p = 0.112). CONCLUSIONS: Our study suggests that the beneficial effects of SCS in refractory angina may also be related to an increase in mean MBF and to a redistribution of MBF between the regions with low or normal basal flow and the regions with high basal flow.

Brain positron emission tomography (PET) in chronic fatigue syndrome: preliminary data.

Chronic fatigue syndrome (CFS) has been widely studied by neuroimaging techniques in recent years with conflicting results. In particular, using single-photon emission computed tomography (SPECT) and perfusion tracers, hypoperfusion has been found in several brain regions, although the findings vary across research centers. The objective of this study was to investigate brain metabolism of patients affected by CFS, using [18F]fluorine-deoxyglucose (18FDG) positron emission tomography (PET). We performed 18FDG PET in 18 patients who fulfilled the criteria of the working case definition of CFS. Twelve of the 18 patients were females; the mean age was 34 +/- 15 years (range, 15-68) and the median time from CFS diagnosis was 16 months (range, 9-138). Psychiatric diseases and anxiety/neurosis were excluded in all CFS patients. CFS patients were compared with a group of 6 patients affected by depression (according to DSM IV-R) and 6 age-matched healthy controls. The CFS patients were not taking any medication at the time of PET, and depressed patients were drug-free for at least 1 week before the PET examination. The PET images examined 22 cortical and subcortical areas. CFS patients showed a significant hypometabolism in right mediofrontal cortex (P = 0.010) and brainstem (P = 0.013) in comparison with the healthy controls. Moreover, comparing patients affected by CFS and depression, the latter group showed a significant and severe hypometabolism of the medial and upper frontal regions bilaterally (P = 0.037-0.001), whereas the metabolism of brain stem was normal. Brain 18FDG PET showed specific metabolism abnormalities in patients with CFS in comparison with both healthy controls and depressed patients. The most relevant result of our study is the brain stem hypometabolism which, as reported in a perfusion SPECT study, seems to be a marker for the in vivo diagnosis of CFS.

Regional cerebral blood flow changes in patients with cirrhosis assessed with 99mTc-HM-PAO single-photon emission computed tomography: effect of liver transplantation.

BACKGROUND/AIMS: Previous studies showed contrasting results with regard to alterations of regional cerebral blood flow/metabolism in subjects with liver cirrhosis. The aim of the study was to extend these findings in a larger series of patients. In addition, we wanted to determine whether such alterations are reversed by successful liver transplantation. METHODS: The study group comprised 23 patients with liver cirrhosis and 13 normal controls. At entry to the study, all subjects underwent a complete neurological examination, EEG recordings and SPECT scanning. The severity of liver disease was determined according to the Child-Pugh score. Fourteen patients underwent a second SPECT examination 1 year after liver transplantation. RESULTS: Significant rCBF reductions, ranging from 6% to 7%, were found in the majority of the cortical regions of the whole group of patients with cirrhosis, as compared to controls. These reductions were more diffuse in patients with alcoholic liver disease, comprising almost all the assayed regions. Liver transplantation normalized cortical rCBF deficits so that postoperative perfusion indexes were superimposable on control values. However, the frontal cortex remained significantly more impaired in patients with alcoholic cirrhosis than in those with non-alcoholic cirrhosis. The differences in frontal rCBF between the two groups of patients ranged from 6 to 11%. CONCLUSIONS: Liver cirrhosis was associated with rCBF defects that depend upon the etiology of liver disease and that subsided after successful liver transplantation. The frontal defects in alcoholic cirrhosis either before or after surgery may imply a neurotoxic, possibly irreversible, action of ethanol.

T wave normalization in infarct-related electrocardiographic leads during exercise testing for detection of residual viability: comparison with positron emission tomography.

OBJECTIVES: We investigated the sensitivity and specificity of exercise-induced T wave normalization (TWN) in infarct-related electrocardiographic leads (IRLs) for detection of residual viability in the infarct area. BACKGROUND: The meaning of exercise-induced TWN on IRLs is not yet well understood. Recent reports suggest that TWN during dobutamine echocardiography could indicate the presence of viable myocardium. METHODS: We evaluated 40 consecutive patients with a recent acute myocardial infarction and negative T waves in at least two IRLs. All patients underwent exercise testing; positron emission tomography (PET) with nitrogen-13 ammonia and fluorine-18 fluorodeoxyglucose; and coronary angiography. RESULTS: Twenty-four patients showed exercise-induced TWN: 18 at a work load < or =50 W (group la) and 6 at a work load > or =75 W (group 1b); 16 patients did not show TWN (group 2). On the PET study, viability in the infarct area was present in 17 patients (94%) from group la, in only 1 (16%) from group 1b and in 4 (25%) from group 2 (p < 0.0001). The sensitivity, specificity and diagnostic accuracy of exercise-induced TWN, in comparison with residual viability, were, respectively, 82%, 67%, 75% for TWN at every work load and 77%, 94%, 85% for TWN at a work load < or =50 W. Moreover, the sensitivity and diagnostic accuracy of TWN at the low work load were higher for anterior infarctions (87% and 88%, respectively). CONCLUSIONS: Exercise-induced TWN on IRLs at low work loads is a sensitive and specific index for the presence of residual viability in the infarct area. Sensitivity and diagnostic accuracy of this sign are higher for anterior infarctions.

Neuroendocrine tumor imaging: can 18F-fluorodeoxyglucose positron emission tomography detect tumors with poor prognosis and aggressive behavior?

We evaluated the clinical value of positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) for neuroendocrine tumor (NET) detection. Sixteen patients with cytologically or histologically proved NETs were investigated. Patients were divided in two groups of eight patients each according to the clinicopathologic features related to prognosis: slow-growing NETs and aggressive NETs. Results of FDG tumor uptake as detected by PET were compared with computed tomography (CT) scans and with scans obtained with 111In-octreotide scintigraphy (n = 13). Tumor FDG uptake was increased in the primary lesion of all eight aggressive NETs; the tracer was shown also in lymph nodes, liver metastases, or both in five of six of them (83%). In four cases, additional unknown tumor sites undetected by CT scan were identified. A slight positivity was found in only one of eight cases with a slow-growing NET. The overall octreotide scintiscan sensitivity was 85%, but in the aggressive NETs it failed to detect the primary lesion in two of seven cases. Uptake of the tracer in some but not all tumor lesions in the same patient was seen by both FDG-PET and octreotide scintiscans. From our limited experience 18F-FDG PET seems to be useful for identifying NETs characterized by rapid growth or aggressive behavior. Uptake of the FDG tracer by the tumor may be related to a worse prognosis. Despite the heterogeneity of tracer uptake in the various lesions of NETs with multiple tumor sites, FDG-PET was able to detect unsuspected distant metastases, contributing to better staging of advanced disease.

Myocardial perfusion, glucose utilization and oxidative metabolism in a patient with left bundle branch block, prior myocardial infarction and diabetes.

A diabetic patient affected by insulin-dependent diabetes, significant stenosis of left anterior descending (LAD) coronary, thrombolyzed myocardial infarction and complete left bundle branch block (LBBB) was examined by PET. Myocardial perfusion, glucose utilization and oxidative metabolism were evaluated by 13N-ammonia, 18F-fluorodeoxyglucose (FDG) and 11C-acetate, respectively. Despite severe damage in 18F-FDG uptake in the septum, with a septum-to-lateral ratio (S/L R) equal to 0.38, the oxidative metabolism in this area, evaluated quantitatively by dynamic acquisition, was relatively preserved (S/L R = 0.82), with a distribution similar to perfusion (S/L R = 0.87). These data reveal selective damage in glucose utilization in the septum in LBBB, unrelated to perfusion reduction and with preserved oxidative metabolism. Moreover, our experience could suggest an overestimation of the necrotic area by 18F-FDG in LBBB patients.

[Positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) in the diagnosis and preoperative staging of head and neck tumors: a prospective study]. / Ruolo diagnostico della tomografia ad emissione di positroni (PET) con 18-fluorodesossiglucosio (FDG) nella stadiazione preoperatoria dei tumori del capo-collo: studio prospettico.

To evaluate the effectiveness of PET with FDG in the preoperative identification of loco-regional lymph node metastases in patients with head and neck tumors a total of 24 consecutive patients coming to the E.N.T. Center were studied. In all cases staging was made using CT and/or MRI and by PET with FDG. All patients then underwent surgery performed by one single team and the histopathological findings were evaluated every time by the same pathologists. The sensitivity (87.5% vs. 53.1%), specificity (99% vs. 87.8%) and diagnostic precision (98.2% vs. 85.3) achieved by PET with FDG proved significantly better than the radiological imaging methods. In particular, given that in the present study PET showed a negative predictive value of 99%, when planning a functional lymphadenectomy this technique can be suggested as a preoperative guide in mapping out lymph node metastases.

Potential role of fluorine-18-deoxyglucose (FDG) positron emission tomography (PET) in the staging of primitive and recurrent medullary thyroid carcinoma.

We investigated 5 MTC patients, 3 preoperatively for staging purpose, and 2 after surgery, during the follow-up, because of the persistence of elevated serum tumoral markers. FDG PET results were compared with conventional radiologic (US, CT scan, MRI) and scintigraphic non-invasive techniques (99mTc-MIBI and 99mTc-MDP scans). In all the 3 patients preoperatively studied, PET, as well as the other imaging modalities, detected the primitive tumor and the loco-regional lymphnode metastases. Furthermore, in one case, PET was the only technique that revealed an additional localization to the lungs. One false negative result was recorded with PET, as well as with the conventional imaging, in a MTC patient with a MEN II syndrome and with some liver micrometastases, 2 to 5 mm sized, showed only at laparotomy. PET was the only method capable of early visualizing a mediastinal relapse of the tumor in one of the 2 patients studied during the follow-up. This patient was re-operated and serum calcitonin levels became undetectable. On the basis of our preliminary results on MTC, PET with FDG seems to be an accurate, non-invasive technique, for staging purpose before surgery, and, during the follow-up for visualizing tumoral spread in patients with increased serum tumoral markers.

The role of fluorine-18-deoxyglucose (FDG) positron emission tomography (PET) whole body scan (WBS) in the staging and follow-up of cancer patients: our first experience.

We report the results of FDG PET whole body scan in 75 cancer patients in whom tumor extent was defined by surgical, histological or cytological findings and clinical follow-up. Twenty-five had malignant lymphomas, 24 lung carcinomas, and 26 other types of solid tumors. Twenty-three patients were evaluated at disease onset, before therapy, and 37 at the moment of tumor recurrence; the remaining 15 patients were in complete remission after treatment and were taken as controls. Visual and quantitative PET results were compared with conventional imaging (US, CT scan and/or MRI, and Tc99m MDP bone scan). In the 60 patients with active disease, PET as well as conventional imaging were able to locate the primary tumor in all 23 patients studied at disease onset. However, with regard to lymph node and distant metastases, PET provided the same information as conventional imaging in 31 cases (51.6%), but revealed further neoplastic foci in 29 cases (48.4%), 21 in lymph nodes and 8 at distant sites. The sensitivity of PET, in comparison with conventional imaging, was 100% versus 100% for the detection of the primary tumor, 97.6% versus 55.8% for the localization of node metastases, and 100% versus 55.5% for the visualization of distant metastases. The specificity, calculated in the group of 15 disease-free patients, was 100% for PET and 86.6% for conventional imaging. The therapeutic approach was modified in 12 patients (20%) on the basis of the PET results. Furthermore, in 14 cases (23.3%) with advanced disease, PET provided complete information on tumor spread, otherwise obtainable only by taking together the results of all other diagnostic procedures. Our data indicate a higher accuracy of FDG PET whole body scan compared to conventional imaging techniques in the evaluation of metastatic spread both at initial diagnosis and during follow-up, with an important impact on therapeutic decision-making. Moreover, by providing complete information on tumor spread in some cases, PET can become a profitable tool in terms of cost reduction.

Prognostic evaluation of patients after myocardial infarction: incremental value of sestamibi single-photon emission computed tomography and echocardiography.

BACKGROUND: This study compares the prognostic value of 99mTc-labeled methoxyisobutyl isonitrile (MIBI) single-photon emission computed tomographic (SPECT) imaging, echocardiography, and other clinical and laboratory prognostic factors in the long-term risk stratification of patients with stable uncomplicated infarcts. METHODS AND RESULTS: Ninety-one consecutive patients affected by a first myocardial infarction without serious complications were enrolled. After at least 3 months from the infarction, they were submitted to stress-rest MIBI SPECT and rest echocardiography. Eighty-six patients completed a follow-up of at least 4 years (range 48 to 72 months; mean 55 months). By univariate (log-rank test) and multivariate analysis (Cox proportional hazards model), the main clinical, electrocardiographic, scintigraphic, and echocardiographic findings were evaluated and correlated statistically with the incidence of ensuing cardiac events. Twenty-five patients had cardiac events during the follow-up (four cardiac deaths, four myocardial infarctions, and 17 cases of unstable angina). At the multivariate analysis, the presence of reversible defects on MIBI SPECT (p = 0.008 and relative risk [RR] = 7.09), the wall motion score index, and the ejection fraction at echocardiography (respectively, p = 0.010, RR = 3.67, p = 0.036, and RR = 3.12), and stress angina (p = 0.007 and RR = 3.40) were significant and independent prognostic factors. CONCLUSIONS: In our long-term follow-up, MIBI SPECT and echocardiography appeared to be significant and independent prognostic tools in the risk stratification of patients with stable, uncomplicated infarcts, furnishing complementary information. The reversibility of MIBI defects appeared the best indicator for a bad prognosis.

[Echocardiography or stress scintigraphy with dipyridamole for the stratification of risk after acute myocardial infarction?]. / Ecocardiografia o scintigrafia da stress con dipiridamolo per la stratificazione del rischio dopo infarto miocardico acuto?

UNLABELLED: Increased risk of subsequent cardiac events after an acute infarction can be identified through dipyridamole infusion. It remains to be determined whether echocardiographic or scintigraphic imaging modes are equivalent. The aim of our study was to compare the prognostic information obtained early after an acute uncomplicated myocardial infarction through high-dose dipyridamole coupled with echocardiography or scintigraphy via Tc 99m sestamibi SPECT imaging. METHODS AND RESULTS: Fifty-one patients underwent simultaneous dipyridamole stress echocardiography and scintigraphy at a mean +/- SD of 12 +/- 3 days after admission for acute uncomplicated myocardial infarction. A subgroup of 44 patients performed exercise testing according to maximal symptom limited protocol. All patients were followed prospectively for 346 +/- 273 days (range 11-959). Cardiac events occurred in 20 patients (39%), and 1 death, 2 myocardial reinfarctions and 17 cases of unstable angina were recorded. Univariate predictors of cardiac events were: positive dipyridamole echo (p < 0.001), ischemia in the infarct zone or in remote zones by echo (p < 0.001), ejection fraction < 40% (p = 0.042) and positive exercise testing (p = 0.003). Risk was best predicted by multivariate Cox analysis on the basis of 1) ischemia in remote zones by dipyridamole echo (p < 0.001) and 2) ischemia in the infarct zone by dipyridamole echo (p = 0.003), blood pressure at peak exercise < 150 mmHg (p = 0.010) and non-Q wave infarction (p = 0.003). CONCLUSIONS: Echocardiographic imaging during dipyridamole infusion is superior to sestamibi scintigraphy for predicting events after uncomplicated myocardial infarction.