[Pacemaker infection in fragile patients]. / Herzschrittmacherinfektion bei fragilen Patienten.

Complications associated with cardiac implantable electric devices (CIED) are manifold. They include lead dislocation, twiddler's syndrome, device malfunction, haematoma formation and infection. Infections can be divided into acute, subacute and late infections. Both the time of onset and the route of infection play a crucial role. The consequences of a CIED infection are devastating. The most modern treatment methods include the removal of all implanted implants. If complete removal is not followed in the event of infection, there is a high rate of infection recurrence. Open thoracic surgery to remove infected CIED hardware has been replaced by percutaneous lead extraction procedures. Lead extraction requires specialised equipment and expertise and may not be readily available or feasible for some patients. Each extraction procedure is associated with a small risk of potentially fatal complications (e.g. cardiac avulsion, vascular avulsion, haemothorax and cardiac tamponade). For these reasons, the performance of such procedures should be limited to centres with adequate equipment and experience. Successful salvage of CIED systems with in situ sterilisation of contaminated hardware has been reported. In our case, we report the successful salvage of an exposed generator in a frail patient treated more than 5 years after the last generator replacement.

Fully integrated [18F]FDG PET/MR in large vessel vasculitis.

BACKGROUND: The aim of this study is to evaluate the usefulness of [18F] fluorodeoxyglucose (FDG) positron emission tomography (PET)/magnetic resonance (MR) in large vessels vasculitis (LVV) patients. METHODS: We performed an observational retrospective study based on our records. Images were acquired on a PET/MR scanner using [18F]FDG-PET whole body imaging. For each PET scan, a qualitative analysis and a semi-quantitative measure using the maximum of the standardized uptake value (SUVmax) were performed. SUVmax measurements normalized to the liver uptake were categorized using a grading scale. Vessel's wall thickness (WT) was measured at five fixed points (inferior margin of T5, T9, T12, L3, thickest area [max WT]). RESULTS: Twenty-three LVV patients were included, 56.5% giant cells arteritis, 34.8% Takayasu's arteritis and 8.7% isolated aortitis, all Caucasian, mostly females (82%). We considered 32 PET scans for the LVV group (from a minimum of one to a maximum of three scans per patient) mainly during follow-up (29/32 scans), and 23 PET scans from a control group of non-metastatic malignancies patients. We found higher SUVmax compared to controls, in all sites, irrespective of clinical disease activity. Mean WT resulted higher in patients than in controls but was not correlated to SUVmax. Mean WT positively correlated with age in both cohorts, inversely correlated to disease duration, while no correlation with SUVmax was observed. The concordance between clinically active disease and PET hypermetabolism was poor (Cohen' κ=0.33). CONCLUSIONS: PET/MR is a safe imaging technique capable of detecting inflammation in aortic wall. Low radiological exposure of PET/MR should be considered especially in young women receiving follow-up studies.

Quantitative analysis of image metrics for reduced and standard dose pediatric 18F-FDG PET/MRI examinations.

OBJECTIVE:: The study performs a comprehensive analysis of image metrics to objectively support the reduction of injected activity in pediatric oncology 18F-FDG PET/MR (18F-fludeoxyglucose PET/MR) examinations. Contrast-to-Noise Ratio (CNR), Normalized Noise (NN), tumor burden, and standardized uptake value (SUV) parameters stability were investigated to robustly define the acceptable reduced activity level that preserves the clinical utility of images, considering different PET applications. METHODS:: 21 PET/MRI examinations performed on a 3-Tesla Biograph mMR scanner were analyzed. Tracer activity reduction was stimulated by decreasing the count statistics of the original list-mode data (3 MBq kg-1). In addition to the already studied SUV metrics and subjective scoring on lesion detectability, a thorough analysis of CNR, NN, Metabolic Tumor Volume (MTV), and Total Lesion Glycolysis (TLG) was performed. RESULTS:: SUVmax and SUVmean increased more than 5% only in 0.6 MBq kg-1 reconstructed images (+10% and +9%, respectively), while SUVpeak was almost unaffected (average variations < 2%). The quantified CNR, NN, MTV, and TLG behavior with the decrease of the injected activity clearly defines 1.5 MBq kg-1 as a threshold of activity after which the quality of the image degrades. Subjective and objective analyses yielded consistent results. All 56 lesions were detected until activity of 1.2 MBq kg-1, whereas five lesions were missed on the 0.6 MBq kg-1 image. Perceived image quality (IQ) decreased in Lower Tracer Activity (LTA) images but remained acceptable until 1.5 MBq kg-1. CONCLUSION:: Results about the stability of image metrics beyond the semi-quantitative SUV parameters and subjective analysis, rigorously proves the feasibility of the reduction of injected activity to 1.5 MBqkg-1 for pediatric patients aged between 7 and 17 years. ADVANCES IN KNOWLEDGE:: This is the first report on the quantitative evaluation of the effect of activity reduction on image quality in pediatric PET/MR. The findings offer objective corroboration to the feasibility of a significant dose reduction without consequences on clinical image reading and tumor burden metrics.

Brain PET and functional MRI: why simultaneously using hybrid PET/MR systems?

INTRODUCTION: In the last 20 years growing attention has been devoted to multimodal imaging. The recent literature is rich of clinical and research studies that have been performed using different imaging modalities on both separate and integrated positron emission tomography (PET) and magnetic resonance (MR) scanners. However, today, hybrid PET/MR systems measure signals related to brain structure, metabolism, neurochemistry, perfusion, and neuronal activity simultaneously, i.e. in the same physiological conditions. A frequently raised question at meeting and symposia is: "Do we really need a hybrid PET/MR system? Are there any advantages over acquiring sequential and separate PET and MR scans?" The present paper is an attempt to answer these questions specifically in relation to PET combined with functional magnetic resonance imaging (fMRI) and arterial spin labeling. EVIDENCE ACQUISITION: We searched (last update: June 2017) the databases PubMed, PMC, Google Scholar and Medline. We also included additional studies if they were cited in the selected articles. No language restriction was applied to the search, but the reviewed articles were all in English. Among all the retrieved articles, we selected only those performed using a hybrid PET/MR system. We found a total of 17 papers that were selected and discussed in three main groups according to the main radiopharmaceutical used: 18F-fluorodeoxyglucose (18F-FDG) (N.=8), 15O-water (15O-H2O) (N.=3) and neuroreceptors (N.=6). EVIDENCE SYNTHESIS: Concerning studies using 18F-FDG, simultaneous PET/fMRI revealed that global aspects of functional organization (e.g. graph properties of functional connections) are partially associated with energy consumption. There are remarkable spatial and functional similarities across modalities, but also discrepant findings. More work is needed on this point. There are only a handful of papers comparing blood flow measurements with PET 15O-H2O and MR arterial spin label (ASL) measures, and they show significant regional CBF differences between these two modalities. However, at least in one study the correlation at the level of gray, white matter, and whole brain is rather good (r=0.94, 0.8, 0.81 respectively). Finally, receptor studies show that simultaneous PET/fMRI could be a useful tool to characterize functional connectivity along with dynamic neuroreceptor adaptation in several physiological (e.g. working memory) or pathological (e.g. pain) conditions, with or without drug administrations. CONCLUSIONS: The simultaneous acquisition of PET (using a number of radiotracers) and functional MRI (using a number of sequences) offers exciting opportunities that we are just beginning to explore. The results thus far are promising in the evaluation of cerebral metabolism/flow, neuroreceptor adaptation, and network's energetic demand.

A new integrated dual time-point amyloid PET/MRI data analysis method.

PURPOSE: In the initial evaluation of patients with suspected dementia and Alzheimer's disease, there is no consensus on how to perform semiquantification of amyloid in such a way that it: (1) facilitates visual qualitative interpretation, (2) takes the kinetic behaviour of the tracer into consideration particularly with regard to at least partially correcting for blood flow dependence, (3) analyses the amyloid load based on accurate parcellation of cortical and subcortical areas, (4) includes partial volume effect correction (PVEC), (5) includes MRI-derived topographical indexes, (6) enables application to PET/MRI images and PET/CT images with separately acquired MR images, and (7) allows automation. METHODS: A method with all of these characteristics was retrospectively tested in 86 subjects who underwent amyloid (18F-florbetaben) PET/MRI in a clinical setting (using images acquired 90-110 min after injection, 53 were classified visually as amyloid-negative and 33 as amyloid-positive). Early images after tracer administration were acquired between 0 and 10 min after injection, and later images were acquired between 90 and 110 min after injection. PVEC of the PET data was carried out using the geometric transfer matrix method. Parametric images and some regional output parameters, including two innovative "dual time-point" indexes, were obtained. RESULTS: Subjects classified visually as amyloid-positive showed a sparse tracer uptake in the primary sensory, motor and visual areas in accordance with the isocortical stage of the topographic distribution of the amyloid plaque (Braak stages V/VI). In patients classified visually as amyloid-negative, the method revealed detectable levels of tracer uptake in the basal portions of the frontal and temporal lobes, areas that are known to be sites of early deposition of amyloid plaques that probably represented early accumulation (Braak stage A) that is typical of normal ageing. There was a strong correlation between age and the indexes of the new dual time-point amyloid imaging method in amyloid-negative patients. CONCLUSIONS: The method can be considered a valuable tool in both routine clinical practice and in the research setting as it will standardize data regarding amyloid deposition. It could potentially also be used to identify early amyloid plaque deposition in younger subjects in whom treatment could theoretically be more effective.

Analytical and experimental FWHM of a gamma camera: theoretical and practical issues.

Introduction. It is well known that resolution on a gamma camera varies as a function of distance, scatter and the camera's characteristics (collimator type, crystal thickness, intrinsic resolution etc). Manufacturers frequently provide only a few pre-calculated resolution values (using a line source in air, 10-15 cm from the collimator surface and without scattering). However, these are typically not obtained in situations resembling a clinical setting. From a diagnostic point of view, it is useful to know the expected resolution of a gamma camera at a given distance from the collimator surface for a particular setting in order to decide whether it is worth scanning patients with "small lesion" or not. When dealing with absolute quantification it is also mandatory to know precisely the expected resolution and its uncertainty in order to make appropriate corrections. Aim. Our aims are: to test a novel mathematical approach, the cubic spline interpolation, for the extraction of the full width at half maximum (FWHM) from the acquisition of a line source (experimental resolution) also considering measurement uncertainty; to compare it with the usually adopted methods such as the gaussian approach; to compare it with the theoretical resolution (analytical resolution) of a gamma camera at different distances; to create a web-based educational program with which to test these theories. Methods. Three mathematical methods (direct calculation, global interpolation using gaussian and local interpolation using splines) for calculating FWHM from a line source (planar scintigraphy) were tested and compared. A NEMA Triple Line Source Phantom was used to obtain static images both in air and with different scattering levels. An advanced, open-source software (MATLAB/Octave and PHP based) was created "ad hoc" to obtain and compare FWHM values and relative uncertainty. Results and Conclusion. Local interpolation using splines proved faster and more reliable than the usually-adopted Gaussian interpolation. The proposed freely available software proved effective in assessing both FWHM and its uncertainty.

Parkinson-like features in ALS with predominant upper motor neuron involvement.

Owing to the frequent observation of poverty of movements, facial hypomimia and balance impairment, amyotrophic lateral sclerosis (ALS) variant with predominance of upper motor neuron involvement (UMN-ALS) is prone to be diagnosed with Parkinsonism. A clinical assessment, including the velocity-dependent stretch response test to differentiate between pyramidal and extrapyramidal stiffness; the Unified Parkinson's Disease Rating Scale and the Berg Balance Scale to assess degree of bradykinesia and postural instability; and (123)I-FP-CIT scintigraphy evaluation to investigate the nigrostriatal circuit involvement, were carried out to characterize Parkinson-like features in UMN-ALS patients. Sixteen UMN-ALS patients were included in the study. The velocity-dependent stretch response indicated spasticity in all the muscles tested. The degree of stiffness was found to be related to bradykinesia and postural instability. Eleven patients (70%) showed a reduction in striatal (123)I-FP-CIT uptake found to be related to disease duration and patients' ages but not to scores of the functional scales. Slowness of movements and postural instability noted in our patients could be mostly attributed to spasticity. The lack of any correlation between UPDRS or BBS scores and the degree of nigrostriatal impairment on DaTSCAN seems to disprove nigrostriatal circuit involvement in these extrapyramidal-like features.

Fine-needle aspiration cytology and (99m)Tc-pertechnetate scintigraphy together in patients with differentiated thyroid carcinoma.

The aim of this study was to evaluate the usefulness of fine-needle aspiration cytology (FNAC) and (99m)Tc-pertechnetate scintigraphy (TS) together in patients with differentiated thyroid carcinoma. Data from a series of 357 patients (284 women and 73 men, median age 43 years, range 19-73) with solitary thyroid nodule and no signs of hyperfunction, who had undergone both FNAC and TS prior to surgery, were retrospectively reviewed. FNAC distinguished 3 groups of TN (benign, follicular neoplasm, cancer), while patients with 'cold' TN were considered at risk of having a thyroid tumor. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were: 95%, 21%, 20%, 95% and 34% for TS; 82%, 99%, 96%, 96% and 96% for FNAC; 98%, 99%, 97%, 98%, and 99% for TS and FNAC together, respectively. In conclusion, patients with 'cold' TN and FNAC suggesting follicular neoplasm should be considered at risk of having cancer.

Presurgical (99m)Tc-sestamibi brain SPET/CT versus SPET: a comparison with MRI and histological data in 33 patients with brain tumours.

PURPOSE: A morphofunctional approach to the management of brain tumours has been claimed to increase diagnostic accuracy. Among the proposed single-photon emission tomography (SPET) tracers, (99m)Tc-sestamibi is able to distinguish recurrent tumour from radio-necrosis and to identify early response or resistance to chemotherapy. Major drawbacks of sestamibi, that is, poor morphological resolution and the sites of physiological uptake, could be overcome by dual-modality, integrated systems. The purpose of this study was to investigate the real usefulness of (99m)Tc-sestamibi SPET/computed tomography (CT) and to establish a semiquantitative index. METHODS: Charts from 33 consecutive patients selected for surgery, who underwent preoperative SPET/CT and magnetic resonance imaging (MRI), were reviewed. Tumours were confirmed histologically after the surgery in all patients and classified according to WHO recommendations. Semiquantitative indexes were obtained on images (maximum likelihood expectation maximization reconstructed) with and without attenuation correction and visual analysis of SPET versus SPET/CT was performed. RESULTS: A significant statistical difference was shown between SPET and SPET/CT in terms of the delineation of medial shift, oedema and the ability to distinguish tumour from the skull-meninges complex and plexus. With regard to semiquantitative indexes, a ratio obtained comparing counts/pixel derived from a region of interest in the tumour area with mirrored region of interest in the contralateral site revealed a sensitivity of 90.9% and specificity of 71.45% in discriminating WHO grade 4 gliomas from a lower grade. CONCLUSION: SPET/CT can distinguish tumour from the skull and other sites of physiological uptake better than SPET alone (as confirmed by MRI in all cases) and affords a morphological map. The proposed semiquantitative index also seems promising in identifying higher-grade disease. SPET/CT thus seems a useful additional tool in brain tumour management, especially when MRI is not feasible or PET/CT is not available.

Usefulness of combined sestamibi scintimammography, axillary ultrasonography and FNA cytology in reducing the number of sentinel node procedures in patients with early-stage breast cancer.

BACKGROUND: Intraoperative analysis of the sentinel lymph node (SLN) status is currently performed in patients with breast cancer (BC) undergoing surgery. Axillary node (AN) metastases are present in up to 60% of cases, but the risk is only 30% in patients with early stage (T1) BC. The aim of this study was to evaluate the usefulness of 99mTc-sestamibi scintimammography (SSM), axillary ultrasonography (US) and US-guided fine-needle aspiration (FNA) cytology together in detecting axillary metastases preoperatively and their potential role in reducing the number of SLN procedures. PATIENTS AND METHODS: A series of 86 consecutive women (median age 57 years, range 30-72) with confirmed BC and clinically negative nodes (T1N0) underwent both SSM and US prior to surgery. US-guided FNA cytology was performed in all the patients with suspicious AN on US, or positive SSM and ultrasonographically visualized enlarged nodes. RESULTS: Final pathology showed 4 pT1bN0, 1 pT1bN1, 60 pT1cN0 and 21 pT1cN1 BC. The sensitivity, specificity, and accuracy were 59.1%, 93.7% and 84.9% for SSM, 63.6%, 90.6% and 83.7% for US, and 72.7%, 97.8% and 90.7% for SSM and US together. Using FNA cytology the specificity reached 100%, but the sensitivity did not increase. A combined method using radioisotope and blue dye was used for SLN biopsy. The procedure was omitted in patients with FNA cytology showing AN metastases (N = 14, 16.3%) and they underwent level I-II axillary dissection, as well as those with positive SLN biopsy on frozen section (8 out of 72, 11.1%). CONCLUSION: In patients with BC, preoperatively selected by SSM and US in whom US-guided axillary FNA cytology has shown the presence of AN metastases, the SLN biopsy can be avoided and AN dissection should be the primary procedure.

Axillary lymph node metastases detection with 99mTc-sestamibi scintimammography in patients with breast cancer undergoing curative surgery.

BACKGROUND: Axillary lymph node (AN) status is the primary prognostic discriminant in patients with breast cancer (BC). Although axillary dissection represents the method of choice for obtaining such information, less invasive procedures have been suggested. The aim of this study was to evaluate the usefulness of 99mTc-sestamibi scintimammography (SSM) in detecting AN involvement in patients with confirmed primary BC undergoing surgery. PATIENTS AND METHODS: A series of 159 consecutive women (median age 54 years, range 36-78 years) with confirmed BC undergoing curative surgery were enrolled in the study. Each patient underwent SSM, from 4 to 12 days prior to surgery. According to the tumour staging, modified radical mastectomy was performed in 41 (25.8%) patients, while 118 (74.2%) patients underwent breast conserving surgery with dissection of the axilla. The results of SSM were compared against the final histological evaluation of the axillary nodes. RESULTS: The final pathology showed 33 (20.8%) pT1b, 90 (56.6%) pT1c, and 36 (22.6%) pT2 breast carcinomas. The greatest diameter of the tumour ranged from 8 to 30 mm (median 16 mm). Sixty patients (37.7%) had axillary node metastases (N1), and 99 (60.3%) had negative nodes (NO). The age of the patients significantly correlated with both size of the tumour (R=0.24, p<0.01) and number of positive nodes (R=0.33, p<0.01). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of SSM in detecting AN metastases were 81.4%, 91.0%, 84.2%, 91.0% and 87.4%, respectively. The sensitivity was higher in patients with three or more positive nodes (27 out of 28, 96.4%), while in patients with two (n=25) or one (n=7) positive nodes, the sensitivity decreased to 80% and 28.6%, respectively. CONCLUSION: SSM may be useful in patients undergoing surgery for BC when a preoperative assessment of axillary lymph node status is required. Unfortunately, the sensitivity of SSM in detecting node metestases in patients with BC is low when the number of involved nodes is two or less. This suggests that other imaging techniques should be used is conjunction with SSM, with the aim of increasing both sensitivity and specificity.

High risk of malignancy in patients with incidentally discovered adrenal masses: accuracy of adrenal imaging and image-guided fine-needle aspiration cytology.

AIMS AND BACKGROUND: The incidental finding of nonfunctioning adrenal masses (incidentalomas) is common, but no reliable criteria in differentiating between benign and malignant adrenal masses have been defined. The aim of this preliminary study was to assess the usefulness of adrenal imaging and image-guided fine-needle aspiration cytology in patients with nonfunctioning adrenal incidentalomas with the aim of excluding or confirming malignancy before surgery. METHODS: Forty-two consecutive patients (18 men and 24 women; median age, 54 years; range, 25-75 years) with incidentally discovered adrenal masses of 3 cm or more in the greatest diameter were prospectively enrolled in the study. All patients underwent helical computerized tomography scan and image-guided fine-needle aspiration cytology, 33 (78.6%) underwent magnetic resonance imaging, and 26 (61.9%) underwent norcholesterol scintigraphy before adrenalectomy. RESULTS: The revised final pathology showed 30 (71.4%) benign (26 adrenocortical adenomas, of which 3 were atypical, 2 ganglioneuromas, and 2 nonfunctioning benign pheochromocytomas) and 12 (28.6%, 95% CI = 15-42) adrenal malignancies (8 adrenocortical carcinomas and 4 unsuspected adrenal metastases). The definitive diagnosis of adrenocortical carcinoma was made according to Weiss criteria and confirmed on the basis of local invasion at surgery or metastases. The sensitivity, specificity and accuracy were 75%, 67% and 83% for computerized tomography scan, 92%, 95% and 94% for magnetic resonance imaging, 89%, 94% and 92% for norcholesterol scintigraphy, and 92%, 100% and 98% for fine-needle aspiration cytology. The sensitivity and accuracy of image-guided fine-needle aspiration cytology and magnetic resonance imaging together reached 100%. Immediate periprocedural complications of fine-needle aspiration cytology occurred in 2 (4.7%) patients: self-limited pneumothorax (n = 1), and severe pain (n = 1) requiring analgesic therapy. No postprocedural or late complications were observed. CONCLUSIONS: With the aim of selecting for surgery patients with a non-functioning adrenal incidentaloma of 3 cm or more in diameter, the combination of magnetic resonance imaging and fine-needle aspiration cytology should be considered the strategy of choice.

Sensitivity and positive predictive value of CT, MRI and 123I-MIBG scintigraphy in localizing pheochromocytomas: a prospective study.

AIM: To establish a standardized non-invasive imaging protocol for patients with pheochromocytoma undergoing surgery. METHODS: A series of 32 consecutive patients (16 men, 16 women; median age 43 years, range 15-71 years) with biochemically confirmed pheochromocytoma underwent computed tomography (CT) scanning, magnetic resonance imaging (MRI) and meta-[I]iodobenzylguanidine (MIBG) whole-body scintigraphy prior to adrenalectomy or excision of extra-adrenal tumour (paraganglioma). RESULTS: At final pathology no malignant pheochromocytomas were found. The tumour was right-sided in 16 (50%) patients, left-sided in 13 (41%), extra-adrenal (sympathetic ganglia, upper abdomen) in two (6%) and bilateral in one (3%) patient. Overall, the median greatest diameter (size) of the tumour was 35 mm (range, 15-90 mm). The sensitivity of CT, MRI and MIBG scintigraphy was 90%, 93% and 91%, and the specificity was 93%, 93% and 100%, respectively. The three patients with false negative scintigraphy had an intra-adrenal tumour, ranging from 20 to 50 mm in size. The presence of necrosis within the mass might justify the lack of significant uptake of radiopharmaceutical in two patients, and the small size (15 mm) of the mass in the other. There were two false positive results with both CT and MRI, and no false positive MIBG scintigraphy, which had the highest (100%) positive predictive value. The combination of MRI+MIBG scintigraphy reached 100% sensitivity and positive predictive value. CONCLUSION: Our data suggest that this imaging protocol should be used in all patients with biochemically confirmed pheochromocytoma.

Role and cost-effectiveness of adrenal imaging and image-guided FNA cytology in the management of incidentally discovered adrenal tumours.

Incidentally discovered adrenal masses (incidentalomas) are relatively frequent and unsuspected incidentalomas (AI) of more than 1 cm in size may be found in 1-5% of patients who have undergone abdominal or chest computed tomography (CT)-scan for unrelated reasons. Once an AI is detected, the two major questions are whether the patient has biochemical evidence of adrenal hyperfunction, and whether the mass is an adrenal metastasis or a malignant adrenal tumour. In most cases (>90%) AI are non-functioning, with a low (<10%) risk of being malignant, and an estimated cumulative risk of malignant transformation of less than 1:1000. However, all patients with non-functioning AI usually undergo several imaging studies, but the impact of imaging techniques and image-guided fine-needle aspiration cytology (FNAC) on the cost-effectiveness in the management of patients is not well established. A single test for disease probabilities is not always more cost-effective than two-test approaches and it has been shown that the cumulative sensitivity and accuracy of both FNAC + magnetic resonance imaging (MRI) and FNAC + norcholesterol adrenal scintigraphy reach 100%, at a similar cost-to-accuracy ratio (7.5 vs. 7.0), whilst the strategy CT-scan + MRI together is less sensitive at a lower cost-to-accuracy ratio. In conclusion, the significance of AI, as well as the optimal management approach to treatment, is still under discussion. However, image-guided FNAC in conjunction with MRI as the exclusive imaging test has the major role and cost-effectiveness in the management of patients with AL, and should be considered the strategy of choice in distinguishing between benign and malignant non-functioning adrenal masses of more than 2 cm in diameter.

Usefulness of 99mTc-pertechnetate scintigraphy and fine-needle aspiration cytology in patients with solitary thyroid nodules and thyroid cancer.

The aim of this study was to evaluate the accuracy of fine-needle aspiration (FNA) cytology and thyroid scintigraphy (TS) in patients with solitary thyroid nodules. We retrospectively reviewed a series of 657 consecutive patients (531 (80.8%) women and 126 (19.2%) men, median age 45 years, range 16-81 years) with solitary thyroid nodules. Prior to surgery, all patients underwent FNA cytology whilst 99mTc-pertechnetate TS was performed in 496 (75.5%) patients. Final histopathology showed 533 (81.1%) benign nodules, including 251 (38.2%) follicular adenomas and 124 (18.9%) thyroid carcinomas. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy in the detection of thyroid cancer were 95.8%, 21.1%, 22.6%, 95.5% and 35.7% for TS, and 81.4%, 99.4%, 97.1%, 95.8% and 96.0% for FNA cytology. The presence of thyroid cancer was confirmed in 92 out of 407 (22.6%) patients with a "cold" nodule, in 4 (4.5%) patients who had normal or increased uptake on TS, in 101 out of 104 (97.1%) patients with smears suggesting malignancy, and in 3 out of 533 (0.6%) smears suggesting benign lesions. In conclusion, the specificity of TS is low and this technique should be abandoned as a routine test in patients with nontoxic thyroid nodules. However, a more careful evaluation should be suggested for patients with cold thyroid nodules and a FNA cytology that reads follicular neoplasm.