18F-FDG PET/CT as predictive and prognostic factor in esophageal cancer treated with combined modality treatment.

PURPOSE: [18F] fluorodeoxyglucose positron emission tomography/computed tomography ([18F] FDG-PET/CT) is used for diagnosis, staging, response assessment and prognosis prediction in different tumors, but its role in esophageal cancer is still debated. The aim of this study was to evaluate the role of semiquantitative baseline PET parameters as possible prognostic and predictive factors in a series of esophageal carcinomas treated with combined modalities. METHODS: 43 patients with esophageal carcinoma were treated with chemoradiotherapy (CRT) followed by surgery in 20 cases and underwent pre-treatment 18F-FDG-PET/CT. Semiquantitative PET parameters were evaluated including Standardized Uptake Value (SUVmax e SUVmean), Metabolic Tumor Volume (MTV) and Total Lesion Glycolysis (TLG) with isocontour of 41 and 50%. Further variables analyzed were gender, primary tumor site, histological type, use of surgery, achievement of a radical resection and the type of chemotherapy regimen. The correlation of all variables with treatment response, loco-regional control (LR), Overall survival (OS) and Disease-Free Survival (DFS) was evaluated. RESULTS: SUVmax, SUVmean50 and SUVmean41 were significantly higher in node-positive cases and in squamous cell carcinomas. With respect to prognostic factors, MTV was found to be correlated with OS: patients with MTV41 < 11.32 cm3 and MTV50 < 8.07 cm3 (both p values = 0.04) showed better 3-year OS rates (33 vs. 20%). Further factors predicting a better prognosis were the use of surgery and radical resection (R0) (both p values < 0.01). CONCLUSIONS: Pre-treatment MTV values were significant prognostic factors for OS, together with the use of surgery and R0 resection in esophageal cancers treated with multimodal therapies.

Role of positron emission tomography in the assessment of disease burden and risk of relapse in patients affected by giant cell arteritis.

Giant cell arteritis (GCA) is characterized by two subsets: cranial GCA and large-vessel GCA (LV-GCA); positron emission tomography (PET) is an essential tool in the diagnosis of LV-GCA. In this study, we aimed to investigate its potential prognostic value in the stratification of relapse risk. We retrospectively revised all the clinical records of patients who received a diagnosis of GCA at an immuno-rheumatology clinic of a University Hospital along 6 years and who underwent to a PET-CT examination at diagnosis. Clinical, laboratory, and imaging data were collected. Relapses were recorded. The study population included 19 patients (10 females, 52.6%; median age 74.0 [65.5-76.0] years), 12 with typical cranial GCA (63%) and 7 (37%) with LV-GCA. Based on PET findings, a diagnosis of aortitis was made in 15/19 patients, including 8/12 patients with a classical cranial GCA (58%). Along a median follow-up of 15 months [4.5-26.5], 4 relapses were observed. All relapsers were male; indeed, the difference in gender distribution was the only variable reaching statistical difference between relapsers and non-relapsers. Specifically, aortitis was not more frequent among relapsers. Our study confirms PET as a valid tool in the identification of LV-GCA with no cranial involvement. We failed to demonstrate a role for PET in the prognostic stratification of GCA, while male gender is suggested as a potential risk factor for GCA relapse.Key Points• A significant proportion of patients with GCA presents with non-cranial disease, the identification of which requires imaging studies, among which PET is particularly useful.• Aortitis might be detected also in patients with the classical, cranial GCA type but does not seem to have prognostic implications, at least in terms of relapse risk.• Male gender is suggested as a risk factor for relapse in GCA.

Does baseline [18F] FDG-PET/CT correlate with tumor staging, response after neoadjuvant chemoradiotherapy, and prognosis in patients with rectal cancer?

BACKGROUND: [18F] fluorodeoxyglucose positron emission tomography/computed tomography ([18F] FDG-PET/CT) may be used for tumor staging and prognosis in several tumors but its role in rectal cancer is still debated. The aim of the present study was to assess the correlation of baseline [18F] FDG-PET parameters with tumor staging, tumor response (tumor regression grade (TRG)), and outcome in a series of patients affected by locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT). METHODS: One hundred patients treated with neoadjuvant CRT and radical surgery were enrolled in the present study. Maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) at the baseline [18F] FDG-PET were calculated. These PET parameters were correlated with tumor staging, histopathological data (TRG1 vs. TRG2-5 and TRG1-2 vs. TRG3-5), disease-free survival, and overall survival. RESULTS: SUVmax and SUVmean of primary tumor were statistically associated with T4-stage. SUVmax, SUVmean, and TLG did not result statistically associated with TRG (TRG1 or TRG1-2). MTV resulted statistically associated with TRG1-2 group (OR 2.9; 95% CI 1.2-7.1). Finally, no PET parameter was significantly associated with disease-free or overall survival. CONCLUSION: Our results showed that baseline [18F] FDG-PET parameters correlated with tumor staging, and only MTV correlated with TRG 1-2. PET parameters failed to predict disease-free and overall survival after treatment completion. The results leave open to further studies the issue of identifying patients suitable for conservative approaches.

Role of molecular imaging in the management of patients affected by inflammatory bowel disease: State-of-the-art.

AIM: To present the current state-of-the art of molecular imaging in the management of patients affected by inflammatory bowel disease (IBD). METHODS: A systematic review of the literature was performed in order to find important original articles on the role of molecular imaging in the management of patients affected by IBD. The search was updated until February 2016 and limited to articles in English. RESULTS: Fifty-five original articles were included in this review, highlighting the role of single photon emission tomography and positron emission tomography. CONCLUSION: To date, molecular imaging represents a useful tool to detect active disease in IBD. However, the available data need to be validated in prospective multicenter studies on larger patient samples.

Deep Inspiration Breath Hold [18F]FDG PET-CT on 4-rings scanners in evaluating lung lesions: Evidences from a phantom and a clinical study / [18F]FDG PET/TC en ausencia de respiración utilizando escáneres de 4 anillos en la valoración de lesiones pulmonares: evidencias de un estudio clínico y con maniquí

Objective: To investigate the clinical feasibility of a Deep Inspiration Breath Hold (DIBH) 18F-FDG PET-CT acquisition in apnea and compare the results obtained between these acts of acquisition in apnea and in Free Breathing in the evaluation of lung lesions. Material and methods: A pre-clinical phantom study was performed to evaluate the shortest simulated DIBH time according to the minimum detectable lesion that can be detected by our ultrasound scanner. This study was conducted by changing acquisition time and sphere-to-background activity ratio values and by using radioactivity densities similar to those generally found in clinical examinations. In the clinical study, 25 patients with pulmonary lesions underwent a standard whole body 18F-FDG PET-CT scan in free breathing followed by a 20 s single thorax acquisition PET/CT in DIBH acquisition. Results: The phantom study indicated that a 20-s acquisition time provides an accurate evaluation of smallest sphere shaped lesions. In the clinical study, PET-CT scans obtained in DIBH studies showed a significant reduction of misalignment between the PET and CT scan images and an increase of SUVmax compared to free breathing acquisitions. A correlation between the %BH-index and lesion displacement between PET and CT images in FB acquisition was demonstrated, significantly higher for lesions with a displacement > 8 mm. Conclusion: The single 20 s acquisition of DIBH PET-CT is a feasible technique for lung lesion detection in the clinical setting. It only requires a minor increase in examination time without special patient training. 20 s DIBH scan provided a more precise measurement of SUVmax, especially for lesions in the lower lung lobes which usually show greater displacement between PET and CT scan images in FB acquisition (AU)

Objetivo: Estudiar la viabilidad clínica de la adquisición 18F-FDG PET-TC en apnea y comparar los resultados obtenidos entre las adquisiciones en apnea y en respiración libre en la valoración de lesiones pulmonares. Material y métodos: Se ha realizado un estudio preclínico en maniquí con objeto de establecer el tiempo mínimo de adquisición en apnea en función de la más pequeña lesión evidenciable con nuestro tomógrafo. Este estudio se obtuvo modificando los tiempos de adquisición y la relación de actividad entre esfera y fondo utilizando actividades parecidas a las encontradas en la práctica clínica. En el estudio clínico, 25 pacientes con lesiones pulmonares fueron evaluados mediante PET-TC con 18F-FDG en respiración libre y posteriormente en apnea de 20 segundos. Resultados: El estudio en maniquí indicó que una adquisición de 20 segundos es adecuada para la valoración de las esferas más pequeñas. En el estudio clínico, las adquisiciones PET-TC obtenidas en apnea mostraron una significativa reducción de la desalineación entre la imagen PET y la imagen TC y un incremento en el valor del SUVmax respecto a las adquisiciones en respiración libre. Hemos demostrado la existencia de correlación entre el %BH-index y la desalineación en respiración libre, significativamente mayor en las lesiones con desalineación superior a 8 mm. Conclusiones: La adquisición PET-TC de 20 segundos en apnea es una técnica viable para la detección de la lesión pulmonar en el entorno clínico y requiere solo un pequeño aumento en el tiempo de examen sin requerir especial entrenamiento del paciente. La adquisición en apnea aporta una medida más precisa del SUVmax, especialmente en las lesiones de los lóbulos inferiores que normalmente presentan una marcada desalineación entre las imágenes PET y TC (AU)

Deep Inspiration Breath Hold [(18)F]FDG PET-CT on 4-rings scanners in evaluating lung lesions: evidences from a phantom and a clinical study.

OBJECTIVE: To investigate the clinical feasibility of a Deep Inspiration Breath Hold (DIBH) (18)F-FDG PET-CT acquisition in apnea and compare the results obtained between these acts of acquisition in apnea and in Free Breathing in the evaluation of lung lesions. MATERIAL AND METHODS: A pre-clinical phantom study was performed to evaluate the shortest simulated DIBH time according to the minimum detectable lesion that can be detected by our ultrasound scanner. This study was conducted by changing acquisition time and sphere-to-background activity ratio values and by using radioactivity densities similar to those generally found in clinical examinations. In the clinical study, 25 patients with pulmonary lesions underwent a standard whole body (18)F-FDG PET-CT scan in free breathing followed by a 20s single thorax acquisition PET/CT in DIBH acquisition. RESULTS: The phantom study indicated that a 20-s acquisition time provides an accurate evaluation of smallest sphere shaped lesions. In the clinical study, PET-CT scans obtained in DIBH studies showed a significant reduction of misalignment between the PET and CT scan images and an increase of SUVmax compared to free breathing acquisitions. A correlation between the %BH-index and lesion displacement between PET and CT images in FB acquisition was demonstrated, significantly higher for lesions with a displacement>8mm. CONCLUSION: The single 20s acquisition of DIBH PET-CT is a feasible technique for lung lesion detection in the clinical setting. It only requires a minor increase in examination time without special patient training. 20s DIBH scan provided a more precise measurement of SUVmax, especially for lesions in the lower lung lobes which usually show greater displacement between PET and CT scan images in FB acquisition.

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

BACKGROUND: Attenuation 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. PURPOSE: The 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 METHODS: Gated-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. RESULTS: The 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. CONCLUSION: The 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).

Two sequential Tc-99m ECD SPECT studies in a case of sporadic Creutzfeldt-Jakob disease confirmed at autopsy.

BACKGROUND: Creutzfeldt-Jakob disease (CJD) is a subacute spongiform encephalopathy characterized by rapidly progressive dementia, hard to diagnose during life. MATERIALS AND METHODS: We present a case of a patient with pathologically confirmed sporadic form of CJD in whom initial diagnostic tests were negative. Two sequential brain single-photon emission computed tomography with Tc-99m ethyl-cysteinate dimer were performed, the first one was performed few days after the admission into hospital and the second, 1 month later. RESULTS: Both studies revealed a decrease in regional cerebral blood flow indicative of neuronal dysfunction, more pronounced in the second study. CONCLUSION: Current radionuclide scintigraphy can be an useful tool for the investigation of CJD.

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.

Residual brain viability, evaluated by (99m)Tc-ECD SPECT, in patients with suspected brain death and with confounding clinical factors.

BACKGROUND: In 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. AIM: The aim of this study was to evaluate the clinical value of single-photon emission computed tomography (SPECT) with technetium-99m (Tc)-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 Tc-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 Tc-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. RESULTS: The 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 Tc-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). CONCLUSION: In patients with confounding factors in whom brain death diagnosis is equivocal, Tc-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.

Elevation of Gas6 protein concentration in cerebrospinal fluid of patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

INTRODUCTION: Gas6 enhances survival of Schwann cells and neurons in vitro and participates in autoimmunity in animal models. Since its concentration in human cerebrospinal fluid (CSF) is unknown, we measured it in samples from patients with non-inflammatory/non-autoimmune neurological diseases (NINAD) and autoimmune polyneuropathies. MATERIALS AND METHODS: Samples collected after informed consent during diagnostic lumbar puncture in the period 1999-2006 were stored at -30 degrees C. We considered subjects with NINAD (stroke, ALS, headache, psychiatric conditions simulating neurological diseases, otologic dizziness) or with Guillain-Barré syndrome (GBS) or CIDP. CSF and plasma total protein and age were obtained from clinical records. Gas6 was measured with an ELISA developed and validated in our laboratory (inter-, intra-assay CVs <10%, recovery 96%). Variance, Tukey's post-hoc test, regression were calculated with a statistical software (Statsoft). RESULTS: Mean Gas6 concentration in patients with NINAD was 6.5+/-2.4 ng/ml, 7.2+/-2.6 ng/ml in GBS and significantly higher (11.5+/-1.7 ng/ml) in CIDP than in the other conditions (post-hoc, p<0.005). It was not related to age, CSF total proteins or to CSF/plasma ratio of total proteins (regression, p>0.1). CONCLUSIONS: Gas6 is detectable in CSF and may be involved in chronic autoimmune demyelination or myelin repair.