Positron emission tomography is a useful tool in differentiating idiopathic from ischemic dilated cardiomyopathy.

We evaluated the utility of positron emission tomography in differentiating patients with idiopathic dilated cardiomyopathy from those with ischemic cardiomyopathy. Twenty consecutive non-diabetic patients with dilatation (end-diastolic volume > or = 120 cc/m2) and reduced systolic function (ejection fraction < or = 40%) of the left ventricle on cineangiography, underwent coronary angiography, F18 fluorodeoxyglucose (F18-FDG) (glucose load technique) and N13-ammonia (N13-NH3) positron emission tomography. A semiquantitative score based on the extension and the severity of the uptake defects was calculated. Endomyocardial biopsy was performed in patients with normal coronary arteries. Ten patients (group A) had normal coronary arteries and histologic features of the endomyocardium fitting with the diagnosis of idiopathic dilated cardiomyopathy. Cineangiography showed critical stenosis of at least one major coronary artery in the other 10 patients (group B). The two groups were similar in age. left ventricular end-diastolic volume and ejection fraction. Both N13-NH3, positron emission tomography and F18-FDG positron emission tomography scores were lower in group A than in group B: 0.1 +/- 0.3 vs. 10.6 +/- 5.1 (P<0.0001) and 2.4 +/- 4.4 vs. 9.9 +/- 4.1 (P<0.0001) respectively. but only N13-NH3 positron emission tomography allowed a complete separation of the two groups (score range 0-1 group A vs. 4-12 group B). The F18-FDG score value showed some overlapping between the two groups (score range 0-12 in the group A vs. 2-17 in the group B). All three idiopathic dilated cardiomyopathy patients with a F18-FDG score value >2 had left bundle branch block on standard ECG. Positron emission tomography imaging with N13-NH3 and F18-FDG provided a complete differentiation between idiopathic dilated cardiomyopathy and ischemic cardiomyopathy patients. However patients with left bundle branch block on ECG could present defects in FDG uptake even if affected by idiopathic dilated cardiomyopathy.

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.

Exercise technetium 99m sestamibi single-photon emission computed tomography late after coronary artery bypass surgery: long-term follow-up.

BACKGROUND AND HYPOTHESIS: The prognostic value of exercise technetium 99m sestamibi single-photon emission computed tomography (SPECT) imaging in patients with previous bypass surgery is unknown. The aim of our study was to assess the prognostic information obtained with exercise scintigraphy performed for routine follow-up or reappearance of symptoms. METHODS: We studied 75 patients referred to our Center at a mean of 38 +/- 53 months from the revascularization procedure and prospectively followed them for 38 +/- 24 months. RESULTS: Fifteen patients (20%) had events at follow-up: there were 4 cardiac deaths, 3 nonfatal acute myocardial infarctions, 8 late revascularization procedures (4 percutaneous transluminal angioplasty and 4 repeat bypass surgery). Univariate analysis identified a history of typical angina (p = 0.001), a clinically positive ergometric test (p = 0.009), peak exercise heart rate (p = 0.0003), percentage of maximal predicted heart rate (p = 0.0001), peak exercise double product (p = 0.048), therapy during exercise (p = 0.003), scintigraphic summed reversibility score (i.e., the summation of the segmental differences between stress and rest) (p = 0.014), as significant predictors of events. Three multivariate models were built, with clinical variables (Model 1, chi square 15.97), ergometric variables (Model 2, chi square 19.66), and with scintigraphic variables added to clinical/ergometric variables (Model 3, chi square 31.13). The scintigraphic variable selected in the model as significant predictor of events was the summed reversibility score (p = 0.008). CONCLUSIONS: Exercise sestamibi SPECT scintigraphy provides optimal prognostic information after clinical and ergometric parameters in patients with previous bypass surgery.

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.

Functional meaning of scintigraphic and echographic patterns, and of circulating anti-peroxidase antibodies in asymptomatic chronic thyroiditis.

Asymptomatic chronic thyroiditis (ACT) is a variant of the autoimmune thyroiditis characterized by the presence of circulating anti-thyroid antibodies and the absence of palpable goiter. Thyroid function can be normal but a considerable percentage of ACT patients tend to develop subclinical hypothyroidism over time and thus periodical controls of thyroid hormones and TSH levels are needed. At present, useful parameters for predicting the functional outcome of ACT patients are lacking. To investigate this aspect, we evaluated 57 consecutive ACT patients (51 females, 6 males, aged 22-56 years) by means of thyroid 99mTc-pertechnetate scintigraphy and echography, and by measuring the serum level of anti-peroxidase antibodies (TPOAbs), FT4, T3 and TSH. At first observation, 30 patients were euthyroid whereas 27 had subclinical hypothyroidism. No patient had been previously treated with thyroid hormones. Thyroid scan showed a normal pattern or a diffuse and mild irregular uptake, without differences between euthyroid and subclinical hypothyroid patients. TPOAb levels tend to be higher in patients with subclinical hypothyroidism in comparison to the euthyroid patients (5893 +/- 1423 and 3943 +/- 912 UI/mL, respectively) but the difference was not statistically significant by using Student's "t"-test. Echography showed a normal pattern in 14 patients, while a diffuse hypoechoic pattern in the other cases, mild in 12, moderate in 19 and marked in 12, was found. A significantly higher prevalence of subclinical hypothyroidism was observed in the group of patients with a moderate or marked hypoechoic pattern in comparison to the group with a normo-echoic or mild hypoechoic pattern (70.4% versus 23.0%, Fisher's exact test p = 0.00003). Furthermore, the 3 patients who developed thyroid failure during a one-year follow-up also presented a moderate or marked hypoechoic pattern. Our data suggest that the echo-pattern can be a useful predictor of thyroid failure in ACT patients and thus the echographic evaluation should be included in the diagnostic protocol of these patients.

Three-phase bone scan pattern in asymptomatic uncemented total knee arthroplasty.

In this study we investigated the bone scan pattern in a homogeneous group of asymptomatic patients implanted with the same type of total knee arthroplasty (TKA) and with a minimum follow-up of 2 years. Twenty-nine patients (21 females, 8 males, mean age 62 years), with a total of 30 uncemented Hofmann TKAs, were entered in the study. The time interval from surgery to scintigraphic evaluation ranged from 2 to 4 years. Bone scan was performed using the three-phase technique and images were interpreted by visual analysis using a three-point scale for the dynamic and blood pool phases and a five-point scale for the bone phase. Areas of increased periprosthetic technetium-99m methylene diphosphonate (MDP) uptake were observed until 4 years after surgery. However, comparing the TKAs implanted 2, 3 and 4 years previously, a decreasing pattern in tracer uptake intensity was noted this being more evident in the femoral and lateral tibial components. In some cases, a persistently elevated tracer uptake, not exceeding a moderate grade, was found in the medial tibial component. In conclusion, increased periprosthetic 99mTc-MDP uptake is a common finding in asymptomatic uncemented Hofmann TKAs for a prolonged period after surgery, but the uptake intensity is generally mild or moderate and shows a characteristic decreasing pattern over time. Furthermore, in contrast with other types of asymptomatic knee implants previously investigated, no case of high or very high bone uptake was recorded with this type of implant. We may speculate that scintigraphic parameters of normality, and pathology, should be determined for each type of TKA. It is likely that, with the uncemented Hofmann TKA, a high or very high tracer uptake or a progressive increase in the uptake intensity is suggestive of the presence of complications.

The role of 111In-octreotide scintigraphy in the detection of APUD tumours: our experience in eighteen patients.

111In-Octreotide scintigraphy has been recently proposed as a sensitive technique for the detection of neuroendocrine tumours, based on the high radiotracer affinity towards the somatostatin receptors expressed by the APUD-system cells. In the present study, a group of 18 patients with carcinoid tumours and gastrointestinal (GI) apudomas was investigated to assess the accuracy of Octreotide scintigraphy in localizing primitive, recurrent or metastatic lesions. Both planar and SPECT studies were obtained 4 hours after the i.v. injection of 111In-Octreotide (111 MBq); planar images were also carried out 24 hours later. In accordance with other authors, the sensitivity of the method was found to be very high (94%) in our group of patients; only in one case of nesidioblastosis was the scintigraphy negative. No differences in sensitivity were observed between the planar and SPECT studies, but the latter provided a better topographic localization of the neoplastic foci. It should be pointed out that in 7 cases (3 primitive, 1 recurrent and 3 metastatic lesions) scintigraphy correctly localized the tumour, when the other morphological techniques, such as echography, computed tomography or magnetic resonance, failed. On the basis of our data, we believe that Octreotide scintigraphy should be the first study performed in the evaluation of patients affected by APUD tumours.

Diagnosis of bone and liver metastases in breast cancer comparing tumor markers and imaging techniques.

One hundred and forty-seven patients were examined by bone scintigraphy, ultrasonography and scintigraphic scan of the liver, at different times after surgical removal of a breast cancer, to rule out skeletal and hepatic metastases. At the same time as imaging procedures, serum levels of tumor markers (CEA, TPA and CA 15-3) were determined using radioimmunometric methods. One or more markers were elevated in all 13 patients with hepatic metastases; 9 out of 46 patients with bone metastases had all serum markers normal, with a sensitivity of 80%. Combined assay of the markers proved useful, TPA and CA 15-3 showing the best sensitivity in bone metastases, and all three markers in liver metastases.

Scintigraphy of the parathyroid glands with 201TI: experience with 250 operated patients.

Parathyroid scintigraphy confirmed its validity in the preoperative localization of enlarged parathyroids, showing a sensitivity of 82% in a series of 250 patients suffering from primary hyperparathyroidism and successfully operated on. The glands better visualized were in an ectopic site or they were completely or partially outside the thyroid so that they were easily visible without employing digital image subtraction. This is nevertheless necessary to visualize parathyroids in a retrothyroid site but some problems arise, related not only to movements of the patient but also to the instrumentation to perform a correct image subtraction.