Pneumorrhachis With FDG Uptake Cervical Lesions on PET/CT of a Patient With Suspected Recurrent Hypopharyngeal Cancer.

ABSTRACT: A 57-year-old man presented with odynophagia for 1 week was referred for FDG PET/CT scan to rule out recurrent hypopharyngeal cancer. The FDG PET/CT showed hypermetabolic lesions in hypopharyngeal area and adjacent cervical spine with pneumorrhachis, the presence of intraspinal air, on attenuation CT images, which might indicate a life-threatening infection. An emergency MRI confirmed the presence of cervical spondylodiscitis with an epidural abscess. The patient rapidly progressed to quadriplegia and difficulty voiding on the same day as the PET/CT scan, leading to emergent operation. The patient received antibiotics treatment and discharged 4 months later without evidence of cancer recurrence.

Extrastriatal uptake related to dopaminergic dysfunction on 99mTc-TRODAT-1 brain SPECT in patient with atypical meningioma.

Extrastriatal accumulation on technetium-99m-([2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]- ethanethiolato(3-)-N2,N2',S2,S2']oxo-[1R-(exo-exo)])(99mTc)-TRODAT-1 is unexpected during nuclear medicine nigrostriatal pathway examinations on 99mTc-TRODAT-1 brain single photon emission computed tomography (SPECT). An 86-year-old female with a history of right hemiparesis, speech expressive difficulties, unstable gait, and bradykinesia on right side was reported. Technetium-99m -TRODAT-1 dopamine transporter SPECT revealed an incidental extrastriatal accumulation of radiotracer in the left anterior frontal region, accompanied by a photopenic area which resulted in the displacement of the left striatum with decreased dopaminergic neuronal function. The brain magnetic resonance imaging (MRI) revealed an invasive meningioma corresponding to the extrastriatal uptake on SPECT, accompanied by edema and mass effect. The patient received surgery and the histopathological results confirmed the diagnosis of atypical meningioma.This study emphasizes the importance of understanding the underlying causes of extrastriatal uptake from 99mTc-TRODAT-1 brain SPECT, which may indicate an invasive brain tumor.

18F-Fluorodeoxyglucose PET/CT for Early Prediction of Outcomes in Patients with Advanced Lung Adenocarcinomas and EGFR Mutations Treated with First-Line EGFR-TKIs.

This study aims to investigate the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in early prediction of response and survival following epithelial growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy in patients with advanced lung adenocarcinomas and EGFR mutations. Thirty patients with stage IIIB/IV lung adenocarcinomas and EGFR mutations receiving first-line EGFR-TKIs were prospectively evaluated between November 2012 and May 2015. EGFR mutations were quantified by delta cycle threshold (dCt). 18F-FDG PET/CT was performed before and 2 weeks after treatment initiation. PET response was assessed based on PET Response Criteria in Solid Tumors (PERCIST). Baseline and percentage changes in the summed standardized uptake value, metabolic tumor volume (bsumMTV and ΔsumMTV, respectively), and total lesion glycolysis of ≤5 target lesions/patient were calculated. The association between parameters (clinical and PET) and non-progression disease after 3 months of treatment in CT based on the Response Evaluation Criteria in Solid Tumors Version 1.1 (nPD3mo), progression-free survival (PFS), and overall survival (OS) were tested. The median follow-up time was 19.6 months. The median PFS and OS were 12.0 and 25.3 months, respectively. The PERCIST criteria was an independent predictor of nPD3mo (p = 0.009), dCt (p = 0.014) and bsumMTV (p = 0.014) were independent predictors of PFS, and dCt (p = 0.014) and ΔsumMTV (p = 0.005) were independent predictors of OS. 18F-FDG PET/CT achieved early prediction of outcomes in patients with advanced lung adenocarcinomas and EGFR mutations receiving EGFR-TKIs.

Dual-time-point 18F-FDG PET/CT in the diagnosis of solitary pulmonary lesions in a region with endemic granulomatous diseases.

OBJECTIVE: Granulomatous diseases (GDs) can be metabolically active and indistinguishable from lung cancer on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) imaging. Evaluation of solitary pulmonary lesions remains a diagnostic challenge in regions with endemic GD. This study sought to determine the efficacy of dual-time-point (DTP) 18F-FDG PET/computed tomography (CT) imaging in diagnosing solitary pulmonary lesions from such regions. METHODS: A total of 50 patients with solitary pulmonary nodules or masses with confirmed histopathological diagnoses underwent DTP 18F-FDG PET/CT imaging at 1 and 3 h after tracer injection. The maximum standardized uptake value (SUVmax) on early and delayed scans (SUV1h and SUV3h, respectively) and retention index (RI) were calculated for each pulmonary lesion. Receiver operating characteristic analysis was performed to evaluate the discriminating validity of the parameters. RESULTS: There were 37 malignant and 13 benign solitary pulmonary lesions. Eight of the 13 (62 %) benign lesions were GDs. The sensitivity/specificity/accuracy of SUV1h, SUV3h and RI were 84/69/80 %, 84/85/84 %, and 81/54/74 %, respectively. SUV3h had the best diagnostic performance, especially regarding specificity. The values of SUV1h and SUV3h were significantly different between malignant lesions and GD, while the RI values of malignant lesions and GD were both high (18.6 ± 19.5 and 18.7 ± 15.3 %, respectively; P = not significant). CONCLUSION: SUV3h appeared to improve the diagnostic specificity of 18F-FDG PET/CT in evaluating solitary pulmonary lesions from regions with endemic GD.

Utility of (18)F-FDG PET/CT in patients with advanced squamous cell carcinoma of the uterine cervix receiving concurrent chemoradiotherapy: a parallel study of a prospective randomized trial.

PURPOSE: The aim of this prospective study was to assess the usefulness of (18)F-FDG PET/CT performed before and during treatment for predicting treatment failure in patients with advanced squamous cell carcinoma of the uterine cervix treated with concurrent chemoradiotherapy (CCRT). METHODS: Patients with cervical squamous cell carcinoma, International Federation of Gynecology and Obstetrics stage III/IVA or positive pelvic or paraaortic lymph node (LN) metastasis without other distant metastasis on PET/CT entering a randomized trial of CCRT (AGOG 09-001) were eligible. PET/CT scans were performed at baseline, during week 3 of CCRT and 2 - 3 months after CCRT. PET/CT parameters were correlated with sites of failure and overall survival (OS). The resulting predictors developed from the study cohort were validated on two independent datasets using area under the curve values, sensitivities and specificities. RESULTS: With a median follow-up of 54 months for survivors, 20 (36 %) of the 55 eligible patients were proven to have treatment failure. Sites of failure were local in five, regional in 11, and distant in 11. Four predictors for local failure, three for regional failure, and four for distant failures were identified. After validation with two independent cohorts of 31 and 105 patients, we consider the following as clinically useful predictors: pretreatment metabolic tumour volume (MTV) and during-treatment cervical tumour MTV for local failure; during-treatment SUVnode (maximum standardized uptake value of LNs) for regional and distant failure, and during-treatment MTV for distant failure. During-treatment SUVnode (P = .001) and cervical tumour MTVratio (P = .004) were independent significant predictors of OS by stepwise Cox regression. CONCLUSION: PET/CT imaging before and during treatment is useful for predicting failure sites and OS, making tailored therapeutic modifications feasible with potential outcome improvement during primary therapy.

Solitary pulmonary nodules differentiated by dynamic F-18 FDG PET in a region with high prevalence of granulomatous disease.

This study determined whether dynamic F-18 FDG PET imaging could differentiate benign from malignant solitary pulmonary nodules (SPNs). Histopathologically confirmed SPNs (10-35 mm), 24 malignant and 10 benign, from 34 patients were studied through both dynamic and static F-18 FDG PET imaging of all patients. Volumes of interest (VOIs) were placed over the pulmonary nodules using a 50% maximum pixel value threshold. The arterial input function was estimated from a left ventricle-defined VOI. Based on Patlak analysis, we calculated the net FDG phosphorylation rate (K(i)) and glucose metabolic rate (MRGlu) of each nodule. The slope values of the time-activity curves (TACs) of the nodules were also determined. Based on the static PET images, maximum and mean standardized uptake values (SUV(max) and SUV(mean), respectively) were calculated. Benign and malignant SPNs had significantly different values for SUV(max), SUV(mean), K(i), MRGlu, and TAC slope, with area under the receiver operating characteristic curves distinguishing benign from malignant nodules. McNemar's test of marginal homogeneity found all the predictors helpful to detect malignant nodules (all, p > 0.05), and combining K(i) and MRGlu, which were generated by dynamic study, yielded a higher specificity of 90%, and a sensitivity of 79%. Among the 10 benign nodules, static SUV imaging correctly classified seven, while dynamic F-18 PET imaging correctly classified nine. Dynamic F-18 FDG PET imaging is valuable in differentiating benign from malignant SPNs, particularly for granulomatous disease.

The changes in brain metabolism in people with activated brown adipose tissue: a PET study.

Brown adipose tissue (BAT) is a highly specialized thermogenic tissue and has profound effects on body weight, energy balance, and glucose metabolism. Body temperature regulation depends on the integrated activities of the autonomic nervous system, which is centered predominantly in the hypothalamus. The purpose of this study was to explore the interaction of brain and the activation of BAT by analyzing differences in brain metabolism between patients with and without activated BAT. Fluorodeoxyglucose (FDG) with positron emission tomography/computer tomography (PET/CT) was used to determine the activation of BAT and brain metabolism. After reviewing FDG PET/CT scans, we retrospectively collected 42 patients, 21 with activated BAT and 21 matched controls without activated BAT. We used the method of defining regions of interest (ROI) to examine differences in metabolism between their hypothalami and voxel (volumetric pixel)-based statistical parametric mapping to analyze the whole brain. Compared with controls, patients with activated BAT had a significant hypermetabolic area in the right inferior parietal lobule (Brodmann area 40) and significant hypometabolic areas in the left insula (Brodmann area 13) and right cerebellum; however, there were no metabolic differences in the hypothalamic regions. Our findings illustrate the close relationship of cold temperature exposure-triggered hypermetabolism in the right inferior parietal lobule and activated BAT. They also support the hypotheses that the insula and cerebellum regulate autonomic functions, which are important for controlling BAT thermogenesis within the central pathways.

The utility of the nonattenuation corrected 18F-FDG PET images in the characterization of solitary pulmonary lesions.

OBJECTIVE: To determine the accuracy of nonattenuation corrected (NAC) F-fluorodeoxyglucose positron emission tomography (F-FDG PET) images in the evaluation of solitary pulmonary lesion as compared with more established methods. METHODS: Fifty-six patients received F-FDG PET/CT for diagnosing solitary pulmonary nodules or mass lesions based on histopathology (n=39) and clinical follow-up (n=17). Visual pulmonary lesion FDG uptake was graded by consensus of two nuclear medicine physicians on both attenuation corrected (AC) [absent, less than mediastinal blood pool (MBP), equal to MBP, greater than MBP] and NAC (absent, less than skin, equal to skin, greater than skin) images. Standardized uptake values (SUV) were also measured from AC images. SUV, visual AC, and visual NAC methods' diagnostic performances were compared, distinguishing benign from malignant pulmonary nodules. RESULTS: There were 34 malignant and 22 benign lesions. Lesion diameter varied from 5 to 100 mm (mean ± SD, 24.0 ± 17.9 mm). The NAC, AC, and SUV method sensitivities and specificities were 100/64%, 91/59%, and 79/77%, respectively. For lesions less than 3 cm, NAC, AC, and SUV methods yielded accuracies of 85%, 78%, and 73%, respectively. The NAC method was the most sensitive and accurate especially for small nodules. CONCLUSION: Visual assessment of NAC F-FDG PET images alone may provide a more accurate characterization of solitary pulmonary lesions.

Interobserver variability among measurements of the maximum and mean standardized uptake values on (18)F-FDG PET/CT and measurements of tumor size on diagnostic CT in patients with pulmonary tumors.

BACKGROUND: (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET) imaging has been shown to be an accurate method for diagnosing pulmonary lesions, and the standardized uptake value (SUV) has been shown to be useful in differentiating benign from malignant lesions. PURPOSE: To survey the interobserver variability of SUV(max) and SUV(mean) measurements on (18)F-FDG PET/CT scans and compare them with tumor size measurements on diagnostic CT scans in the same group of patients with focal pulmonary lesions. MATERIAL AND METHODS: Forty-three pulmonary nodules were measured on both (18)F-FDG PET/CT and diagnostic chest CT examinations. Four independent readers measured the SUV(max) and SUV(mean) of the (18)F-FDG PET images, and the unidimensional nodule size of the diagnostic CT scans (UD(CT)) in all nodules. The region of interest (ROI) for the SUV measurements was drawn manually around each tumor on all consecutive slices that contained the nodule. The interobserver reliability and variability, represented by the intraclass correlation coefficient (ICC) and coefficient of variation (COV), respectively, were compared among the three parameters. The correlation between the SUV(max) and SUV(mean) was also analyzed. RESULTS: There was 100% agreement in the SUV(max) measurements among the 4 readers in the 43 pulmonary tumors. The ICCs for the SUV(max), SUV(mean), and UD(CT) by the four readers were 1.00, 0.97, and 0.97, respectively. The root-mean-square values of the COVs for the SUV(max), SUV(mean), and UD(CT) by the four readers were 0%, 13.56%, and 11.03%, respectively. There was a high correlation observed between the SUV(max) and SUV(mean) (Pearson's r=0.958; P <0.01). CONCLUSION: This study has shown that the SUV(max) of lung nodules can be calculated without any interobserver variation. These findings indicate that SUV(max) is a more valuable parameter than the SUV(mean) or UD(CT) for the evaluation of therapeutic effects of chemotherapy or radiation therapy on serial studies.

Appropriate time for post-therapeutic I-131 whole body scan.

Iodine metabolism and kinetics in thyroid carcinoma cells may be different from that in normal thyroid tissue. The optimal time for performing post-therapeutic scans to detect metastatic lesions is still controversial.We retrospectively analyzed the images of 239 patients who received I-131 therapy at our hospital from January 2006 to May 2008. The therapeutic dose ranged from 1.1 GBq (30 mCi) to 7.4 GBq (200 mCi) and the patients received 3 sequential whole body scans on the third to fourth day, fifth to sixth day, and 10th-11th day after I-131 administration. We scored the I-131 avid lesions by visual assessment into 3 grades: 2=clearly visible; 1=visible; and 0=not visible. We also compared the thyroglobulin levels and FDG uptake among the lesions with probably different kinetics of iodine metabolism.In this study, there was a trend of decreasing visualization of lesions in the sequential images. Twenty-eight percent of lymph node metastases, 17% of lung metastases, and 16% of bone metastases were missed on the late images on 10-11th day. On the other hand, only 5% of the remnants were missed. The ratio of early washout was different between remnants and metastatic lesions. The serum thyroglobulin levels and FDG uptake did not correlate with early washout of the I-131 avid lesions. We concluded that earlier imaging is necessary for detection of metastatic lesions.

Sequential follow-up of serum thyroglobulin and whole body scan in thyroid cancer patients without initial metastasis.

OBJECTIVE: To investigate the usefulness of whole body scan (WBS) and serum thyroglobulin (Tg) measurement after thyroxine withdrawal during sequential follow-ups in patients with differentiated thyroid cancer (DTC). DESIGN: Two hundred and sixty-five consecutive DTC patients were enrolled. They were previously treated with near-total thyroidectomy and I-131 remnant ablation, without initial metastases or Tg antibodies. All had the first follow-up WBS and serum Tg measurement 6-12 months after initial treatment, and 165 patients received the second follow-up without further therapy. Positive/negative predictive values (PPV/NPV) were calculated by the outcome of patients being followed up for more than 8 years (mean+/-SD: 133+/-26 months). RESULTS: Serum Tg levels while the patients were off thyroxine therapy decreased spontaneously in 39.3% of the cases without further therapy. The NPV of the first follow-up serum Tg level was excellent: <2 microg/L and <0.5 microg/L were 95.1% and 98.2%, respectively. However, the PPV of the first follow-up serum Tg level was low: >10 microg/L and 2-10 microg/L were 40% and 9.6%, respectively. The trend of Tg levels was more informative; the PPV was 62.5% in cases with an increase of serum Tg of >10 microg/L and 16.6% with an increase of <5 microg/L. However, decreasing Tg levels may associate with rapid deterioration of disease, in which cases decrease of Tg indicated dedifferentiation of the tumor. The diagnostic WBS showed the same picture in 91.5% of the patients. Only one patient (0.6%) turned from negative study to positive during the follow-up. In the meanwhile his serum Tg levels increased from 0.56 to 13.6 microg/L. CONCLUSION: It is most informative when both the trend and the levels of Tg during sequential follow-up are considered. The diagnostic WBS may be performed for selected patients with indication based on Tg levels to localize the disease.

Influence of 131I diagnostic dose on subsequent ablation in patients with differentiated thyroid carcinoma: discrepancy between the presence of visually apparent stunning and the impairment of successful ablation.

BACKGROUND: In the management of patients with differentiated thyroid carcinoma, direct comparison of the presence of scintigraphic stunning after a diagnostic dose of 131I with subsequent successful ablation has not been evaluated. METHODS: This study included 245 patients who received a dose of 2775-3700 MBq of 131I for thyroid remnant ablation. In all patients, the thyroid-stimulating hormone (TSH) level before ablation was more than 30 microlU x ml. One hundred and twenty-six patients (Group A) were given a 185 MBq diagnostic scan (Dscan) 4-11 days before 131I ablation, and 119 patients (Group B) received 131I ablation directly after thyroidectomy. Scintigraphic stunning was considered to be present on any post-ablation scan that revealed either fewer foci or obviously less prominent uptake compared with the earlier corresponding Dscan. Successful ablation was defined as no visible uptake in the neck region or anywhere else on a follow-up Dscan 6-12 months later. RESULTS: Our results revealed that only 13 of the 126 patients (10.3%) in Group A had visually apparent thyroid stunning. Successful ablation was obtained in 56 of 126 cases (44.4%) in Group A, compared with 86 of 119 cases (72.2%) in Group B (P<0.001). In Group A, the success rate of ablation in patients with stunning (5/13) was not statistically different from that in those without (51/113) (odds ratio, 0.76; 95% CI, 0.23-2.47). Multiple logistic regression analysis revealed that the independent determinants of successful ablation were the use of Dscan before ablation (odds ratio, 0.23; 95% CI, 0.10-0.56) and the ablation dose of 131I (odds ratio, 1.05; 95% CI, 1.00-1.10). CONCLUSIONS: Visually apparent stunning is infrequent and may not be sufficiently sensitive to detect the influence of a 185 MBq Dscan on subsequent ablation outcome. For patients with differentiated thyroid carcinoma, we recommend that ablation should be performed directly after thyroidectomy.