Thyroid incidentaloma identified by ¹8F-fluorodeoxyglucose positron emission tomography with CT (FDG-PET/CT): clinical and pathological relevance.

OBJECTIVE: The percentage of patients with thyroid cancer incidentally diagnosed during a (18) F-fluorodeoxyglucose Positron Emission Tomography with computed tomography (CT) (FDG-PET/CT) for nonthyroid diseases ranges between 26% and 50%. DESIGN: Retrospective assessment of the clinical and pathological features of thyroid incidentalomas at FDG-PET/CT, aiming to identify potential predictors of malignancy. PATIENTS: Fifty-two patients with incidental thyroid uptake at FDG-PET/CT were retrospectively included [38 W, age 64·1 ± 12·5 years (mean ± SD)]. An arbitrary cut-off level of 5·0 for the 'maximum standardized uptake value' (SUV max) was chosen to differentiate benign from malignant tumours. Complete thyroid function, neck ultrasonography (US) features, and cyto-histological results were reported for all cases. RESULTS: In our institution, the prevalence of incidental thyroid (18) F-fluorodeoxyglucose ((18) F-FDG) uptake was nearly 1·76%. The prevalence of focal uptake correlated with greater risk of malignancy (P < 0·01). In particular, the euthyroidism (P < 0·003) and a SUV max >5·0 (P < 0·0001) were associated with the diagnosis of thyroid cancer. Diffusely increased FDG-PET/CT uptake in the thyroid was related to benign conditions. CONCLUSIONS: The presence of focal uptake with high SUV max and euthyroidism correlate with high likelihood of malignancy. Performing a neck US would have to be recommended in all patients with euthyroidism and an incidental FDG-PET/CT focal thyroid uptake. We do not suggest to use FDG-PET/CT as a screening tool for thyroid cancer in the general population, because of both its high cost and low incidence of thyroid incidentaloma at FDG-PET/CT.

Characterization of the [(153)Sm]Sm-EDTMP pharmacokinetics and estimation of radiation absorbed dose on an individual basis.

[(153)Sm]Sm-EDTMP is a radiopharmaceutical used in palliation cares of bone metastases. The purpose of this study is to provide an explicit description of [(153)Sm]Sm-EDTMP pharmacokinetics, adopting a simple three-compartmental model with the analytical expressions calculating the rate constants and determining biodistribution parameters, like radiopharmaceutical uptake and clearance. This biokinetic model allowed us to calculate on an individual basis the dose to bone surface and to red bone marrow and to assess the degree of variability in dosimetric parameters using a fixed administered activity based only on patient weight. In this study twenty patients were enrolled and were treated with [(153)Sm]Sm-EDTMP, administering a fixed activity per kilogram (37 MBq/kg); blood and urine samples were collected during 24 h post treatment. The median value of the administered activity was 2.7 GBq. Blood clearance confirmed that an aliquot of [(153)Sm]Sm-EDTMP rapidly localizes and is retained in bone, while the remainder is rapidly cleared from the blood pool by the urinary system. Our data show a bi-exponential clearance from blood: the rapid component has a half life median value of 6 min (range: 2-24 min), while the slow one has a half life median value of 1.4 h (range: 0.6-5.8 h). Median value of the urinary excretion is 40 (range: 3-75) % of the administered activity. Our model shows the behaviour of a tracer which is distributed in the extracellular space of the body, localized in the skeleton and excreted via glomerular filtration. Half life median values of [(153)Sm]Sm-EDTMP transferring between compartments, T(1/2) (blood→ECF), T(1/2) (ECF→blood) are 7.4 (range: 1.9-37) and 48 (range: 8-408) min, respectively. Median values of half lives of [(153)Sm]Sm-EDTMP clearance through the urine and of uptake into bone are 1.0 (range: 0.1-6.0) and 1.6 (range: 0.6-9.0) h, respectively. Median value of red marrow absorbed dose is 2.1 (range: 0.7-3.5) Gy and 0.8 (range: 0.3-2.1) Gy/GBq, while median value of bone surface absorbed dose is 11.5 Gy (range: 5.0-18.4) and 4.4 (range: 2.3-14.3) Gy/GBq. It is remarkable that there is a really great biological variability within patients, especially considering the excreted activity. The cumulated activity in bone and red marrow doses were significantly higher in prostate cancer, where metastatic bone lesions are osteoblastic, than in breast cancer where metastatic bone lesions are osteolytic or mixed (lytic/blastic). The relevant biological variability in biodistribution and metabolism of [(153)Sm]Sm-EDTMP suggests that the fixed administered activity based on patient weight is not sufficient to optimize the treatment and a better optimization would be reached by using a predictive dosimetry tailored to individual patient characteristics.

Impact of target-to-background ratio, target size, emission scan duration, and activity on physical figures of merit for a 3D LSO-based whole body PET/CT scanner.

The aim of our work is to describe the way in which physical figures of merit such as contrast-to-noise ratio (CNR) behave when varying acquisition parameters such as emission scan duration (ESD) or activity at the start of acquisition (A(acq)) that in clinical practice can be selected by the user, or object properties such as target dimensions or target-to-background (T/B) ratio, which depend uniquely on the intrinsic characteristics of the object being imaged. Figures of merit, used to characterize image quality and quantitative accuracy for a 3D-LSO based PET/CT scanner, were studied as a function of ESD and A(acq) for different target sizes and T/B ratios using a multivariate approach in a wide range of conditions approaching the ones that can be encountered in clinical practice. An annular ring of water bags of 3 cm thickness was fitted over an IEC phantom in order to obtain counting rates similar to those found in average patients. The average scatter fraction (SF) of the modified IEC phantom was similar to the mean SF measured on patients with a similar scanner. A supplemental set of micro-hollow spheres was positioned inside the phantom. The NEMA NU 2-2001 scatter phantom was positioned at the end of the IEC phantom to approximate the clinical situation of having activity that extends beyond the scanner. The phantoms were filled with a solution of water and 18F (12 kBq/mL) and the spheres with various T/B ratios of 22.5, 10.3, and 3.6. Sequential imaging was performed to acquire PET images with varying background activity concentrations of about 12, 9, 6.4, 5.3, and 3.1 kBq/mL, positioned on the linear portion of the phantom's NECR curve, well below peak NECR of 61.2 kcps that is reached at 31.8 kBq/mL. The ESD was set to 1, 2, 3, and 4 min/bed. With T/B ratios of 3.6, 10.3, and 22.5, the 13.0, 8.1, and 6.5 mm spheres were detectable for the whole ranges of background activity concentration and ESD, respectively. The ESD resulted as the most significant predictor of CNR variance, followed by T/B ratio and the cross sectional area of the given sphere. Only last comes A(acq) with a weight more than halved with respect to ESD. Thus, raising ESD seems to be much more effective than raising A(acq) in order to obtain higher CNR, which is the physical figure of merit closely related with target detectability, at least in the simple task of the signal known exactly background known exactly model.

[Suicidal behaviour in young people. An epidemiological study in the Verbano-Cusio-Ossola Province (years 1988-2000)]. / Le condotte suicidarie giovanili. Una ricerca epidemiologica nella provincia del Verbano-Cusio-Ossola (anni 1988-2000).

BACKGROUND: The aim of the present study is to investigate the suicide and attempted suicide phenomenon among young people (<25 years old) in the Verbano-Cusio-Ossola province from January 1988 to December 2000. METHODS: This epidemiological-descriptive survey is based on the acquisition of data through the examination of model 45 registered at the Verbania Public Prosecutor's office. The data obtained were analysed with SPSS 8.0 software for Windows. The significance of the differences between the rates observed in our group and those observed in Italy in the same period was estimated by calculating SMR and SIR (Standardized Mortality Rates and Standardized Incidence Rates respectively). RESULTS: In the period considered in our study, 13 suicides and 62 attempted suicides were notified to the Court, with a rate of 2.55 and 12.18 per 100,000 inhabitants, respectively. The analysis of SMR and SIR points out that the incidence of suicide and attempted suicide among young people is higher in this province than in Italy. The most frequently used methods to commit suicide are hanging and carbon monoxide poisoning, while drug intoxication prevails in attempted suicide. The most common reasons are disagreements, followed by mental illness, psychosocial factors, loss of a relative and toxic dependence. CONCLUSIONS: The present study means to provide a description of suicide behaviour among young people in a geographic and cultural context, in order to point out its problems and to provide useful information for the diagnosis and prevention.

Recent applications of the sentinel lymph node concept: preliminary experience in prostate cancer.

AIMS AND BACKGROUND: Following the widespread use of radioguided surgery (RGS) in melanoma and breast cancer, we applied this new surgical strategy to prostate cancer (PC). The aims of this study were 1) to evaluate the accuracy of RGS in the detection of prostatic sentinel lymph nodes (SLN), and 2) to verify if pelvic lymphadenectomy (LAD) is an accurate means to detect solitary micrometastases. STUDY DESIGN: We investigated 48 patients with PC confirmed by transrectal biopsy who underwent radical prostatectomy and bilateral LAD. A dose of 99mTc-labeled nanocolloid particles was injected into the prostate after needle positioning by ultrasonography. Serial imaging was obtained with a gamma camera, identifying 1) the first radioactive lymph node (sentinel lymph node, SLN); 2) other radioactive lymph nodes, and 3) non-active lymph nodes. RESULTS: Forty-three SLNs were identified in 48 patients. Twenty SLNs were located at unusual sites with respect to the extent of conventional LAD. Five SLNs were positive for micrometastases and two of these were located outside the usual LAD area. No micrometastases were found in any of the remaining lymph nodes (active and non-active). CONCLUSIONS: These preliminary results are in agreement with the few previous scientific contributions available on this topic and indicate that it is possible to reduce the extent and duration of surgery and necessary to reevaluate the conventional sites of lymphatic drainage.

Detection of moderate and severe coronary artery stenosis with technetium-99m tetrofosmin myocardial single-photon emission tomography.

The aim of this study was to determine the diagnostic accuracy of technetium-99m tetrofosmin myocardial imaging for the localization of coronary artery stenoses of different degrees of severity. Stress-rest single-photon emission tomography (SPET) was performed on separate days in 80 patients (64 males, 16 females; mean age 61 years; 43 patients with previous myocardial infarction; 18 patients with pharmacological stress), within 6 months of coronary angiography. Scintigraphic images were blindly and independently evaluated by three observers. Coronary stenosis was defined as a >50% narrowing in luminal diameter; severe stenosis was defined as a proximal stenosis of >75% or a peripheral stenosis of >90%. Coronary angiography revealed normal coronary arteries or insignificant coronary stenosis in 13 patients and significant coronary stenoses in 67 patients. The sensitivity and specificity of 99mTc-tetrofosmin SPET in respect of severely stenosed vessels were, respectively, 80% and 65% for the left anterior descending artery (LAD), 100% and 46% for the right coronary artery (RCA) and 58 and 78% for the left circumflex artery (LCx) territories. Considering all the significantly stenosed vessels, a significant decrease in sensitivity was observed for LAD territories (to 59%, P=0.05), and a nonsignificant decrease for RCA (88%) and LCx (47%) territories while specificity values remained essentially unchanged. No significant changes in sensitivity or specificity were observed when regions with previous myocardial infarction were excluded. In conclusion, the sensitivity of 99mTc-tetrofosmin SPET for the localization of individual stenosed vessels is only moderate when all significant stenoses are considered, but the ability of this technique to predict the location of severe coronary artery stenoses seems satisfactory, with the exception of the low specificity in respect of RCA territories.

Feasibility of a rapid method to evaluate platelet survival time.

UNLABELLED: The purpose of this study was to evaluate the feasibility of a shorter method of performing platelet kinetic studies with respect to the conventional 8-9-day approach. METHODS: We studied 41 patients (28 women, 13 men; mean age 52 yr) with primary idiopathic thombocytopenic purpura (ITP) (n = 20), secondary ITP (n = 9), HCV associated thrombocytopenia (n = 9), splenectomy (n = 1) and hairy-cell leukemia (n = 1). The patients were in a steady-state of platelet turnover. Initial platelet counts ranged from 19 to 302 x 10(9)/liter (mean value = 83). Platelet survival times (PST) were measured from the blood radioactivity disappearance curve of 111In-oxine-labeled autologus platelets following the recommendations of the International Committee for Standardization in Haematology: blood samples were taken at 30 min and 2 and 4 hr and thereafter daily for 7 days. PST was calculated by the weighted mean method and ranged from 18 to 219 hr (mean value = 98). PST was also calculated using only the data collected at 2, 48 and 96 hr. If the radioactivity in the blood at 96 hr exceeded 10% of the 2-hr value, the additional point at 168 hr was used. RESULTS: By using this reduced dataset, we obtained a correlation of r = 0.97 with the PST obtained from the whole dataset. In 24 patients, the difference was between +/- 10 hr and exceeded 1 day in only 4. CONCLUSION: About 94% of the data may be recovered with only three or four blood samples and the duration may be shortened to 4 days in a significant proportion of patients (48% of ITP patients). This approach offers the advantages of increased patient throughput, compliance and reduced examination costs.

Quantitative scintigraphic evaluation of total knee arthroplasties: a feasibility study.

For the development and validation of a quantitative approach to the analysis of bone scans after total knee arthroplasty, 39 consecutive patients with 40 prostheses (6 males, 33 females; mean age, 70 years) were scheduled for clinical, radiographic, and scintigraphic examination ranging from 9 to 90 months after surgery. Twenty-seven total knee arthroplasties were considered to be asymptomatic and 13 symptomatic according to the clinical and radiographic findings. Significant differences were found for 99mTc-methylene diphosphonate uptake for femur and tibia and between symptomatic and asymptomatic patients. A reference range was determined for radionuclide uptake in the periprosthetic bone of the 27 asymptomatic total knee arthroplasties; this range was then used to identify loose total knee arthroplasties among the 13 symptomatic knees. With a clinical and radiographic followup performed 1 year after scintigraphy as a standard of comparison, a sensitivity of 88% (7/8) and a specificity of 100% (5/5) was demonstrated. These preliminary results suggest the feasibility of a quantitative approach to the scintigraphic evaluation of total knee arthroplasties after the first postsurgical year.

Postoperative infections after neurosurgery and cardiosurgery: the value of labelled white blood cells.

Post surgical-infections in neurosurgery and cardiosurgery are infrequent, but potentially fatal complications. The aim of this study was to compare the utility of 99mTc-HMPAO white blood cells scintigraphy (WBCS) with traditional diagnostic approaches in post-surgical complications, in order to obtain timely demonstration of a current infection. We studied 23 patients with a suspicion of infection after major cardiosurgery or neurosurgery. Planar imaging was performed at 4 and 20 hours after injection of autologous white blood cells labelled with 99mTc-HMPAO. Eight patients underwent CT scan, but only in one case did CT findings lead to a clear definition of a bulky inflammation process of the chest. WBCS identified one or more sites of focal increased uptake of the radiopharmaceutical in 6 patients: five of these patients were scheduled for a "second look" surgical operation that confirmed the sites and extention of the primary infection, thus confirming the presence of an abscess. In 3 cases WBCS showed only a weak increase of focal uptake and in 14 cases there was no evidence of abnormal uptake. The absence of deep infections was confirmed at surgery or at clinical follow-up. Thus WBCS seems to be useful in evaluating patients with the clinical suspicion of infective complications after surgery.

The clinical value of prostate-specific antigen and bone scintigraphy in the staging of patients with newly diagnosed, pathologically proven prostate cancer.

Recent reports suggest that radionuclide bone scan (BS) may not be necessary in the standard staging evaluation of patients with prostate cancer when serum prostate-specific antigen (PSA) levels are normal. To evaluate the ability of PSA to predict BS findings, we retrospectively reviewed the case records of 118 consecutive patients (median age 73 years, range 50-90 years) with newly diagnosed, untreated, pathologically proven prostate cancer who underwent BS and serum PSA sampling within a period of no more than 3 months. Fifty-four out of 118 BSs demonstrated metastatic bone disease. A PSA value of less than 10 ng/ml excluded bone metastasis; of 35 patients with a serum PSA level of 20 ng/ml or less, seven had a positive BS (negative predictive value of 80%). These findings provide additional confirmation of the value of low serum PSA concentrations in excluding the need for a staging BS, although the threshold for a high value of negative predictive accuracy is lower than previously reported.

Assessment of interferon cardiotoxicity with quantitative radionuclide angiocardiography.

Three different types of cardiovascular sequelae attributed to interferon therapy have been reported: arrhythmia, ischaemic heart disease and cardiomyopathy. We evaluated the left ventricular ejection fraction (LVEF) during alpha interferon therapy (3 MU administered subcutaneously three times a week for 6 months) in 11 patients with chronic viral hepatitis. LVEF was within the normal range in all patients (mean value +/- SD 64.6 +/- 10.7%) before interferon was started, but decreased after 1 month of therapy (mean value +/- SD 59.7 +/- 8.3%) (P = 0.015). An LVEF reduction of more than 10% was observed in five of the 11 patients. Three months after therapy was stopped, nine of the 11 patients showed an LVEF close to the pre-treatment level (mean value +/- SD 62.1 +/- 8.3%). In our patients with chronic C hepatitis, low subcutaneous doses of interferon alpha often decreased the LVEF. It is not clear whether this finding is due to the direct effect of interferon on cardiac cells, or to the peripheral vascular effects of the drug. As LVEF reduction could be critical in patients with previously reduced myocardial contractility, our results further highlight the need for careful cardiac analysis before starting interferon therapy.

[The autologous splenic reimplant in the rat]. / Reimpianto splenico autologo nel ratto.

In order to evaluate the clinical utility of autologous splenic transplantation in the omental pouch, a pneumococcal challenge was performed in 3 groups of rats, after demonstration of vitality of the intraperitoneal inoculum: Group A: splenectomized rats; Group B: reimplanted rats; Group C: sham operation. No statistically significant difference was found between the first two groups regarding resistance against infection (p less than 0.982), while normal rats proved more resistant (p less than 0.031). Between group A and B significant differences (p less than 0.001) exists only for a more precocious mortality in the first group. The poor clinical utility of the technique is demonstrated.

[CA 15-3 associated with CEA and TPA in the follow-up of breast carcinoma]. / CA 15-3 in associazione a CEA e TPA nel follow-up del carcinoma mammario.

The serum level measurement of CA 15-3 antigen was evaluated in association with CEA and TPA, during the follow-up in mastectomized patients previously affected by breast cancer: 94 patients with metastases and 319 without apparent disease evolution. In the group of patients with metastases, the CA 15-3 antigen showed high sensitivity (70.2%). The CA 15-3 and TPA association increased the sensitivity (87.2%), while the CEA and CA 15-3 association did not increase this parameter. All markers showed good correlation with therapeutic response. Thirteen patients among 19 without apparent disease evolution, developed metastases, during the follow-up. The CA 15-3 and/or TPA increase allowed to predict disease progression in 13/13 cases, 2-10 months before clinical evidence. Our experience shows that CA 15-3 measurement associated with TPA, during the follow-up of patients affected by breast cancer, may be helpful for increasing the predictivity with respect to those patients most likely to develop recurrent disease.