Silvia Lucchini

F-18 FDG-PET/CT evaluation of patients with differentiated thyroid cancer with negative I-131 total body scan and high thyroglobulin level.

Purpose: The aim was to evaluate the incremental diagnostic rate of F-18 fluoro-fluorodeoxygulose positron emission tomography/computed tomography (F-18 FDG-PET/CT) in patients with negative I-131 whole body scans and high Tg levels. The secondary end points were correlations between F-18 FDG-PET/CT positive results and Tg levels and comparison between F-18 FDG-PET/CT accuracy in patients “on-therapy” with suppressed thyroid stimulating hormone (TSH) and those with high TSH levels. Methods: We studied 52 patients who had undergone total thyroidectomy and remnant ablation; they had high Tg levels (average = 156 ng/mL; SD ± 274) after 3 weeks of levothyroxine withdrawal and negative I-131 total body scans after therapeutic doses. Results: We noted a statistically significant positive correlation between F-18 FDG-PET/CT positive results and Tg levels, irrespective of levothyroxine therapy regimen. Tg levels between F-18 FDG-PET/CT positive/negative groups were significantly different and we did not note any statistically significant correlation between F-18 FDG-PET/CT results and TSH levels, tumor size, and combination of Tg/TSH levels. Conclusions: Our results indicate that F-18 FDG-PET/CT is a useful diagnostic tool in patients with differentiated thyroid carcinoma and with negative I-131 total body scans and high Tg levels. The levothyroxine therapy regimen does not influence F-18 FDG-PET/CT results and the rate of F-18 FDG-PET/CT positive results appears to correlate with the Tg levels. The highest accuracy is reached when the study is performed for patients with Tg levels higher than 21 ng/mL.

Possible role of F18-FDG-PET/CT in the diagnosis of endocarditis: preliminary evidence from a review of the literature

Infective endocarditis (IE) is a particular disease which presents with a variety of clinical, aetiological forms and is lethal if not aggressively treated with antibiotics alone or in combination with surgery. This review tries to analyse the possible role of F18-FDG-PET/CT in the diagnosis of IE based on the state of art in literature.

CSF Alzheimer's disease-like pattern in corticobasal syndrome: evidence for a distinct disorder

Background Corticobasal syndrome (CBS) has a heterogeneous neuropathological spectrum, ranging from the classical corticobasal degeneration to Alzheimers disease (AD). The neuropathology of CBS is still unpredictable. CSF tau/abeta ratio is a reliable marker of AD. Objective To evaluate the presence of a distinct clinical and neuroimaging CBS phenotype according to CSF pattern. Methods 30 patients fulfilling current clinical criteria for CBS entered the study. Each patient underwent a clinical and standardised neuropsychological assessment, and CSF analysis (total tau and abeta42 dosages). CSF AD-like pattern and CSF non-AD like pattern (nAD-like) were identified. In 23 CBS cases, 99mTc-ECD single photon emission computed tomography (SPECT) scan was performed and analysed by statistical parametric mapping. Results CSF AD-like pattern was reported in six cases (20%). The two subgroups did not differ in demographic characteristics or global cognitive impairment. The AD-like group showed greater impairment of memory performances, language and psychomotor speed while the nAD-like group had more severe extrapyramidal syndrome with comparable apraxia scores. Voxel by voxel analysis on SPECT images demonstrated that CBS AD-like patients had greater hypoperfusion in the brain areas typically affected by AD—namely, precuneus, posterior cingulate and hippocampus, bilaterally—compared with nAD-like patients (p<0.001). No clusters above the pre-established threshold were detected when nAD-like were compared with AD-like patients. Conclusions CSF AD-like profile in CBS is associated with earlier memory impairment and brain abnormalities typically found in classical AD. These findings argue for the usefulness of CSF testing to identify AD in CBS, and might suggest a different pharmacological approach on the basis of biological data.

Residual brain viability, evaluated by 99mTc-ECD SPECT, in patients with suspected brain death and with confounding clinical factors

BackgroundIn 1968, the Harvard criteria for brain death diagnosis were introduced in clinical practice. These include no movements or breathing, no reflexes, and flat electroencephalogram in the absence of confounding factors, including hypothermia, drugs, electrolyte, and endocrine disturbances. When confounding factors occur, confirmatory tests documenting the absence of cerebral blood flow, such as cerebral angiogram, transcranial Doppler sonography, computed tomography angiography, and nuclear techniques, are required. AimThe aim of this study was to evaluate the clinical value of single-photon emission computed tomography (SPECT) with technetium-99m (99mTc)-ECD in the diagnosis of brain death in a cohort of patients with confounding factors. Fifty-two patients were studied between 1 January 2000 and 23 September 2008. The criteria for the request for 99mTc-ECD SPECT were sodic thiopental withdrawal after less than 24 h, unreceptivity and unresponsivity of brainstem reflexes, anesthesia in the last 24 h, hypothermia, anamnesis for barbiturate use, electroencephalogram artefacts, toxic state, and pediatric criteria. All patients underwent 99mTc-ECD SPECT using a dual-headed camera fitted with a high-resolution low-energy collimator. Images were reconstructed and processed according to standard procedures and interpreted qualitatively by two experienced observers. ResultsThe presence of spots of residual brain viability was observed in 13 patients: 25% of our patient cohort. The patients with residual viability were younger (aged 30.92±17.28 years) in comparison with those with no viability (41.91±18.77 years, P<0.031). Considering the eligibility for transplantation, there were 12 of 13 patients in the residual viability group and 31 of 39 in the no viability group (P<0.0001). All patients with spots of brain uptake were monitored daily by 99mTc-ECD SPECT, and all of them reached the condition of empty skull after one or multiple studies. The opposition to organ donation was observed in six of 13 patients with spots of viable brain tissue and in three of 39 with no signs of residual viability (P<0.001). ConclusionIn patients with confounding factors in whom brain death diagnosis is equivocal, 99mTc-ECD SPECT is a helpful and safe diagnostic approach, allowing a three-dimensional evaluation of cortical and brainstem viability. It guarantees an unequivocal diagnosis of brain death for patients who are potential candidates for organ donation. The persistence of viable spots of brain tissue was found in 25% of our patients and was more frequent in young patients. This affects the opposition to donation.

The value of attenuation correction by hybrid SPECT/CT imaging on infarct size quantification in male patients with previous inferior myocardial infarct.

BackgroundAttenuation correction (AC) has been shown to improve the accuracy of myocardial perfusion single photon emission computed tomography (SPECT) for the detection and evaluation of patients with coronary artery disease. Attenuation artifacts, because of diaphragmatic attenuation, frequently affect the evaluation of the inferior wall, especially in male patients. PurposeThe aim of this study was to evaluate the value of AC for the assessment of infarct size in coronary artery disease patients after inferior myocardial infarction. Materials and methodsGated-SPECT with Tc-labeled compounds with AC by hybrid SPECT/computed tomography (CT) was performed in 56 male patients with documented previous inferior myocardial infarction. Both corrected and uncorrected SPECT images were processed after motion and scatter correction by ordered-subset expectation maximization iterative reconstruction. When needed, a manual realignment between SPECT and computed tomography (CT) sections was performed. Uncorrected and corrected SPECT images were analyzed for perfusion using a 5-point segmental scoring scale from 0 (normal) to 4 (absent). Summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) of the inferior left ventricle wall (inferoseptal, inferior, infero-apical and infero-lateral segments) were determined and compared with the regional wall motion score as determined by uncorrected gated-SPECT. ResultsThe SSS, SRS, SDS for attenuation-uncorrected and attenuation-corrected studies were 14.02±7.9, 9.51±7, 4.5±3.2 and 9.39±7.1, 5.6±6.1, 3.8±2.8, respectively. Differences were statistically significant (P<0.0001) for SSS and SRS but not for SDS. The regional summed rest score of the inferior wall (SRS of inferior segments) showed a better correlation with the regional summed wall motion score of the same segments: R2=0.50 in comparison to uncorrected SRS, R2=0.46. ConclusionThe combination of diaphragmatic attenuation and inferior myocardial infarction determines an artifactual overestimation of infarct size of inferior infarcts. The AC regional perfusion score (SRS) correlates with the regional wall motion score of the inferior wall. AC does not affect the detection and size of residual ischemia (SDS).

Absence of urine production due to renal failure enables clear visualization of primary urinary bladder carcinoma on 18F-FDG PET/CT.

An 81-year-old man affected by renal failure, underwent 18F-FDG PET/CT for detecting primary lesion because of multiple lung nodules consistent with secondary lesions revealed by computed tomography without contrast. PET study documented high pathologic uptake at anterior and upper wall of urinary bladder, and a primary urinary bladder cancer was suspected. Biopsy confirmed the presence of a high-grade transitional cell carcinoma.

Congenital triple kidney in a patient evaluated by F-18 FDG PET/CT for oncologic reason.

Abstract:We report a case of a 78-year-old man with a left apical lung mass suspected to be an adenocarcinoma previously evaluated by thorax computed tomography, who underwent F-18 FDG PET/CT as a staging study. It revealed the unexpected presence of 3 congenital kidneys, 1 on the left side and 2 on

131I Whole-Body Scan Incidental Uptake Due to Spermatocele

A 46-year-old man with papillary thyroid cancer post total thyroidectomy was referred for post radioiodine (I) whole-body scan. Whole-body images revealed intense I uptake in the bed thyroid and a focal abnormal uptake in the testicular area. Subsequent SPECT/CT demonstrated that the focal uptake corresponded to the left epididymis, and the pathology report revealed a spermatocele with no immunohistochemical features for thyroid tissue. Many cases of unexpected radioiodine uptake have been reported, and spermatocele could be counted for another possibility of incidental I uptake despite an unclear mechanism.