Correction to: [18F]-FDG-PET/CT and [18F]-FAZA-PET/CT Hypoxia Imaging of Metastatic Thyroid Cancer: Association with Short-Term Progression after Radioiodine Therapy.

This article was update to correct the spelling of Takashi Yoshiura's name; it is correct as displayed here.

[18F]-FDG-PET/CT and [18F]-FAZA-PET/CT Hypoxia Imaging of Metastatic Thyroid Cancer: Association with Short-Term Progression After Radioiodine Therapy.

PURPOSE: To examine the relationships between 2-deoxy-2-[18F]fluoro-D-glucose ([18F]-FDG) and hypoxia tracer [18F]fluoro-azomycinarabinofuranoside ([18F]-FAZA) and between 131I and [18F]-FAZA uptake in patients with metastatic thyroid cancer and to evaluate imaging features associated with short-term progression after 131I therapy. PROCEDURES: The study population was 20 patients (17 women and 3 men; mean age, 67 years) with metastatic thyroid cancer who underwent both [18F]-FDG- and [18F]-FAZA-positron emission tomography (PET)/X-ray computed tomography (CT) examinations before 131I therapy. Short-term response to radioiodine was assessed (mean follow-up, 19 months ± 9). PET parameters including [18F]-FDG-SUVmax, [18F]-FAZA-SUVmax, and [18F]-FAZA-tumor-to-muscle [T/M] were obtained. Mann-Whitney U, Wilcoxon signed-rank, or χ2 tests were used to assess differences between two quantitative variables or compare categorical data. Predictive factors for short-term progression were investigated with logistic regression analysis. RESULTS: Eleven lymph node metastatic lesions were identified in 9 patients and 46 distant metastatic lesions (lung, 19; bone, 17; and liver, 10) in 14 patients. A total of 24 131I-positive and 33 131I-negative lesions were detected. SUVmax was significantly lower with [18F]-FAZA-PET/CT (1.3 ± 0.6) than with [18F]-FDG-PET/CT (6.4 ± 5.9, p < 0.001). No significant correlation was observed between [18F]-FAZA-PET/CT and 131I imaging concerning visibility (p = 0.36). After 131I therapy, 31 of 57 metastatic lesions displayed short-term progression. Multivariate logistic regression revealed that [18F]-FDG-SUVmax (p = 0.022) and [18F]-FAZA-T/M (p = 0.002) showed significant associations with short-term progression. CONCLUSIONS: Although [18F]-FAZA uptake was low in metastatic thyroid cancers, not only glucose metabolism but also hypoxic conditions may be associated with progression after 131I therapy in patients with metastatic thyroid cancer.

Angiopoietin-like Protein 2 is a Useful Biomarker for Pancreatic Cancer that is Associated with Type 2 Diabetes Mellitus and Inflammation.

Pancreatic cancer is one of the tumors with the worst prognosis, with the 5-year survival rate reported to be 6%. The number of patients suffering from pancreatic cancer in recent years has continued to increase dramatically. Carbohydrate antigen 19-9 is an established biomarker of pancreatic cancer, but it does not have sufficient ability to detect pancreatic cancer at an early stage. We focused on angiopoietin-like protein 2 (ANGPTL2), which has been reported to be related to chronic inflammation and Type 2 diabetes mellitus. In this study, whether ANGPTL2 can detect early pancreatic cancer was evaluated. It was found that the concentration of serum ANGPTL2 was significantly higher in pancreatic cancer patients and tumor stage 0-I patients than in healthy individuals (5.84 ± 1.82 ng/mL vs 3.61 ± 0.64 ng/mL; P < 0.001) (5.68 ± 0.79 ng/mL vs 3.61 ± 0.64 ng/mL; P = 0.010). In addition, the diagnostic capability of serum ANGPTL2 levels for pancreatic cancer was evaluated using receiver operating characteristic (ROC) curve analysis. The area under the ROC curve (AUC) for ANGPTL2 was 0.906 (95% confidence interval (CI): 0.815-0.997; P < 0.001). To identify the risk factors for pancreatic cancer, multivariate regression models were used. Ten factors were included, and increasing age (odds ratio (OR), 1.318, 95% CI, 1.058-1.642; P = 0.014) and high ANGPTL2 levels (OR, 22.219, 95% CI, 1.962-251.659, P = 0.012) were found to be independent risk factors for pancreatic cancer, with ANGPTL2 having the strongest relationship. In addition, serum ANGPTL2 levels were strongly correlated with inflammatory markers, with blood sugar levels showing the strongest correlation with serum ANGPTL2 levels. In conclusion, this study suggested that an elevated serum ANGPTL2 level has the potential to be a biomarker capable of early detection of pancreatic cancer, and it was correlated with inflammation of the pancreas and the risk of developing diabetes mellitus.

A small pancreatic hamartoma with an obstruction of the main pancreatic duct and avid FDG uptake mimicking a malignant pancreatic tumor: a systematic case review.

BACKGROUND: Pancreatic hamartomas are extremely rare and may be misdiagnosed as malignant tumors. We report herein a case of a small, solid-type pancreatic hamartoma. CASE PRESENTATION: A 72-year-old female was incidentally detected pancreatic lesion by ultrasonography. Computed tomography and magnetic resonance imaging revealed a 2.0-cm solid lesion. The main pancreatic duct (MPD) was obstructed by the lesion in the head of the pancreas, and the upstream MPD was dilated. 18F-fluorodeoxyglucose (FDG) accumulated avidly in the lesion and increased in FDG intensity from the early to the delayed images. The histopathological studies confirmed the diagnosis of pancreatic hamartoma. Immunohistochemically, the cell membrane of the accessory glands and ducts showed homogeneous expression of glucose transporter type I and hexokinase II. CONCLUSION: Pancreatic hamartomas causing dilatation of the MPD are extremely rare, and this appears to be the first case of a hamartoma to take up FDG avidly. It was a rare occurrence and should be noted that pancreatic hamartomas can cause an obstruction of the MPD and show avid FDG uptake, thereby mimicking malignant pancreatic tumors.

A pilot study for texture analysis of 18F-FDG and 18F-FLT-PET/CT to predict tumor recurrence of patients with colorectal cancer who received surgery.

PURPOSE: This retrospective study was done to examine whether the heterogeneity in primary tumor F-18-fluorodeoxyglucose (18F-FDG) and 18F-3'-fluoro-3'-deoxythymidine (18F-FLT) distribution can predict prognosis of patients with colorectal cancer who received surgery. METHODS: The enrolled 32 patients with colorectal cancer underwent both 18F-FDG- and 18F-FLT-PET/CT studies before surgery. Clinicopathological factors, stage, SUVmax, SUVmean, metabolic tumor volume (SUV ≥ 2.5), total lesion glycolysis, total lesion proliferation and seven texture heterogeneity parameters (coefficient of variation, local parameters: entropy, homogeneity, and dissimilarity; and regional parameters: intensity variability [IV], size-zone variability [SZV], and zone percentage [ZP]) were obtained. Progression free survival (PFS) was calculated by the Kaplan-Meier method. Prognostic significance was assessed by Cox proportional hazards analysis. RESULTS: Eight patients had eventually come to progression, and 24 patients were alive without progression during clinical follow-up [mean follow-up PFS; 55.9 months (range, 1-72)]. High stage (p = 0.004), high 18F-FDG-IV (p = 0.015), high 18F-FDG-SZV (p = 0.013) and high 18F-FLT-entropy (p = 0.015) were significant in predicting poor 5-year PFS. Other parameters did not predict the disease outcome. At bivariate analysis, disease event hazards ratios for 18F-FDG-IV and 18F-FDG-SZV remained significant when adjusted for stage and 18F-FLT-entropy (18F-FDG-IV; p = 0.004 [adjusted for stage], 0.007 [adjusted for 18F-FLT-entropy]; 18F-FDG-SZV; p = 0.028 [adjusted for stage], 0.040 [adjusted for 18F-FLT-entropy]). CONCLUSION: 18F-FDG PET heterogeneity parameters, IV and SZV, have a potential to be strong prognostic factors to predict PFS of patients with surgically resected colorectal cancer and are more useful than 18F-FLT-PET/CT heterogeneity parameters.

Combined assessment of serum folate and hemoglobin as biomarkers of brain amyloid ß accumulation.

A relationship between Alzheimer's disease (AD) and folate has been reported. Amyloid positron emission tomography (PET) is currently one of the most reliable biomarkers for AD. We investigated the correlation between serum folate levels and amyloid imaging to clarify whether serum folate could be a biomarker for AD. We also examined the usefulness of a combined assessment of serum folate levels and red blood cell hemoglobin content. Apolipoprotein E (APOE) gene polymorphisms were also assessed. Serum folate levels and hemoglobin content were evaluated by receiver operating characteristic analysis for their diagnostic capability as AD biomarkers relating to brain amyloid ß accumulation. The area under the ROC curve (AUC) for serum folate was 0.136 (95% confidence interval [CI]: 0.000-0.312; p = 0.016). The AUC for hemoglobin content was 0.848 (95% CI: 0.661-1.000; p = 0.021). Therefore, the folate deficiency with low folate levels or the non-anaemia with high hemoglobin content levels were found to have a high probability of also testing positive for amyloid. Furthermore, eight patients were found to be folate deficiency and non-anaemia, those who were consist of 7 amyloid positive patients (87.5%), and only one of the amyloid negative patients (12.5%). These results suggest that a deficiency of serum folate and high hemoglobin levels may reflect an increased risk of amyloid ß accumulation in the brain. Additionally, we demonstrated that these biomarkers could enhance the effectiveness of APOE as an AD biomarker. This study reveals that the combined assessment of serum folate levels and red blood cell hemoglobin content may be a useful biomarker for amyloid ß accumulation in the brain. We also found that the combination of serum folate levels and hemoglobin content is a more specific and sensitive blood biomarker for AD than APOE or folate alone. These findings may be used to support clinical diagnosis of AD using a simple blood test.

A pilot study of the diagnostic and prognostic values of FLT-PET/CT for pancreatic cancer: comparison with FDG-PET/CT.

PURPOSE: The purpose of the study was to examine the diagnostic and prognostic values of 18F-fluorothymidine (FLT)-PET/CT for pancreatic cancer by comparing with 18F-fluorodeoxyglucose (FDG)-PET/CT. METHODS: Fifteen patients with newly diagnosed pancreatic cancer underwent both FLT and FDG-PET/CT scans before treatment. The sensitivity, specificity, and accuracy in detecting nodal and distant metastases were compared between both scans using McNemar exact or χ 2 test. Progression-free survival (PFS) and overall survival (OS) were calculated by Kaplan-Meier method. Prognostic significance was assessed by Cox proportional hazards analysis. RESULTS: Both scans visualized all primary cancers. The sensitivity, specificity, and accuracy per patient basis for detecting nodal metastasis were equal and 63.6% (7/11), 100% (4/4), and 73.3% (11/15) for both scans, and for detecting distant metastasis were 100% (6/6), 88.9% (8/9), and 93.3% (14/15) for FDG-PET/CT, and 50.0% (3/6), 100% (9/9), and 80.0% (12/15) for FLT-PET/CT, respectively, without significant difference in each of them between both scans (p > 0.05). However, of 4 patients with multiple liver metastases, FDG-PET/CT was positive in all, but FLT-PET/CT was negative in three patients. At univariate analysis, only FLT-SUVmax correlated with PFS (hazard ratio, 1.306, p = 0.048), and FDG total lesion glycolysis (TLG), FLT-SUVmax, and FLT-total lesion proliferation (TLP) correlated with OS (p = 0.021, p = 0.005, and p = 0.022, respectively). At bivariate analysis, FLT-SUVmax was superior to FDG-TLG or FLT-TLP for prediction of OS [HR (adjusted for FDG-TLG), 1.491, p = 0.034, HR (adjusted for FLT-TLP), 1.542, p = 0.023]. CONCLUSION: FLT-PET/CT may have a potential equivalent to FDG-PET/CT for detecting primary and metastatic cancers except liver metastasis. FLT-SUVmax can provide the most significant prognostic information.

Current clinical status of 18F-FLT PET or PET/CT in digestive and abdominal organ oncology.

Positron emission tomography (PET) or PET/computed tomography (CT) using 18F-3'-fluoro-3'-deoxythymidine (18F-FLT) offers noninvasive assessment of cell proliferation in human cancers in vivo. The present review discusses the current status on clinical applications of 18F-FLT-PET (or PET/CT) in digestive and abdominal oncology by comparing with 18F-fluorodeoxyglucose (18F-FDG)-PET (or PET/CT). The results of this review show that although 18F-FLT uptake is lower in most cases of digestive and abdominal malignancies compared with 18F-FDG uptake, 18F-FLT-PET can be used to detect primary tumors. 18F-FLT-PET has shown greater specificity for N staging than 18F-FDG-PET which can show false-positive uptake in areas of inflammation. However, because of the high background uptake in the liver and bone marrow, it has a limited role of assessing liver and bone metastases. Instead, 18F-FLT-PET will be a powerful tool for monitoring response to treatment and provide prognostic information in digestive and abdominal oncology.

FLT-PET/CT diagnosis of primary and metastatic nodal lesions of gastric cancer: comparison with FDG-PET/CT.

PURPOSE: To examine the diagnostic performance of (18)F-fluorothymidine (FLT)-PET/CT of primary and metastatic nodal lesions of gastric cancer by comparing with (18)F-fluorodeoxyglucose (FDG)-PET/CT. METHODS: The enrolled study population comprised 17 patients with 17 newly diagnosed gastric cancers who underwent surgery of the primary lesion and regional nodes after both FDG- and FLT-PET/CT scans. Visual detectability of the primary gastric lesions was correlated with pathological factors using the Fisher exact or Mann-Whitney U test. The sensitivity, specificity, and accuracy in detecting nodal lesions were compared between both PET/CT scans using the McNemar exact or χ (2) test. RESULTS: Fourteen of 17 (82.4%) primary cancers were visualized by both FDG- and FLT-PET/CT scans. Although FDG or FLT visibility was not significantly associated with tumor size (p = 0.16) or histological type (p = 1.00), the 3 nonvisible lesions were pathologically early (T1) cancers. The sensitivity, specificity, and accuracy for detecting nodal metastasis were 44.8% (13/29), 98.7% (164/166), and 90.8% (177/195) for FDG-PET/CT, and 31.0% (9/29), 100% (166/166), and 89.7% (175/195) for FLT-PET/CT, respectively. No significant difference was found between the two scans in sensitivity (p = 0.13), specificity (p = 0.48), or accuracy (p = 1.00). CONCLUSION: FLT-PET/CT may have the same diagnostic value as FDG-PET/CT for detection of primary and nodal lesions of gastric cancer.

Increased 18F-FDG Uptake in the Spleen and Multiple Lymph Nodes in Dengue Fever.

A 62-year-old man underwent a whole-body FDG PET/CT for annual cancer screening. By an interview, he had an epigastric pain, and his body temperature was 37.0°C on the day. He just came back home from a travel to Southeast Asia 1 week ago and had presented with chill, high fever (temperature, 39.6°C), arthralgia, myalgia, and skin rash a few days before. Dengue fever was diagnosed by detecting dengue virus type 1 genome and antibody to the virus accompanied by thrombocytopenia and leukopenia. PET/CT examination revealed increased FDG uptake in the spleen and multiple lymph nodes.

[A case of bilateral blephaloptosis resulting from midbrain lesions caused by diffuse large B-cell lymphoma].

We report the case of a patient with bilateral blephaloptosis associated with a recurrence of diffuse large B-cell lymphoma (DLBCL) in the midbrain. A 70-year-old man experienced acute onset bilateral blephaloptosis; the other ocular movements, except for medial rectus muscle in the right eye, were not impaired. Pupils were isocoric and light reflexes were prompt. Other cranial nerves were intact. Gadolinium-enhanced MRI revealed abnormal enhancement in the midbrain and peri-ventricular regions. FDG-PET revealed an abnormal positive signal in the midbrain, similar to the distribution seen in the MRI scan. Cytology of the cerebrospinal fluid showed large atypical lymphocytes. These findings suggest that the recurrence of DLBCL in the midbrain caused bilateral blephaloptosis. The oculomotor fascicle is localized in the paramedian ventral midbrain. The fascicular fibers are divided topographically into four regions; the lateral, medial, rostral and caudal regions. In three-dimensional arrangement of the oculomotor fascicle, the fibers to the levator palpebrae superioris muscle and medial rectus muscles are located adjacently in caudal regions. Thus, we speculate that recurrence of DLBCL in the midbrain involving the right oculomotor fascicle caused blephaloptosis in the right eye, and then, infiltration of DLBCL to the left oculomotor fascicle subsequently caused blephaloptosis in the left eye. This is a valuable case to be documented in which neurological site of lesions consistent with those are found in radiological study.

A Case of Intraductal Papilloma of the Breast With High 18F-FDG Uptake on PET/CT.

We present a case of intraductal papilloma in the right breast of a 51-year-old woman with high F-FDG uptake. Its maximum standardized uptake value increased from 10.2 on early (1 h) PET/CT scan to 12.2 on delayed (2 h) PET/CT scan suggesting a primary breast cancer. However, histopathology proved it to be an intraductal papilloma. Immunohistochemically, strong expression of glucose transporter-1 and weak expression of hexokinase-II were noted in the papilloma. With the detection of a subareolar intracystic mass with high F-FDG uptake, intraductal papilloma should be included in the differential diagnosis.

FDG-PET/CT and FLT-PET/CT for differentiating between lipid-poor benign and malignant adrenal tumours.

OBJECTIVE: To compare F-18-fluorodeoxyglucose (FDG) and F-18-fluorothymidine (FLT) PET/CT examinations for differentiating between benign and malignant adrenal tumours. METHODS: Thirty lipid-poor benign and 11 malignant tumours of 40 patients were included. FDG- and FLT-based indices including visual score, maximum standardized uptake value (SUVmax) and FDG adrenal lesion/liver SUVmax (A/L SUVmax) or FLT adrenal lesion/back muscle SUVmax (A/B SUVmax) ratio were compared between benign and malignant tumours using the Mann-Whitney's U or Wilcoxon signed-rank test, and their diagnostic performances were evaluated by means of the area under the curve (AUC) values derived from the receiver operating characteristic analysis. RESULTS: All indices were significantly higher in malignant than benign tumours on both images (p < 0.05 each). On FDG-PET/CT, the sensitivity, specificity, and accuracy were 91 %, 63 % and 71 % for visual score, 91 %, 67 % and 73 % for SUVmax, and 100 %, 70 % and 78 % for A/L SUVmax ratio, respectively. On FLT-PET/CT, they were 100 %, 97 % and 98 % for visual score, SUVmax and A/B SUVmax ratio, respectively. All FLT indices were significantly higher than those of FDG in AUC (p < 0.05 each). CONCLUSION: FLT-PET/CT may be superior to FDG-PET/CT in differentiating lipid-poor benign from malignant adrenal tumours because of higher specificity and accuracy. KEY POINTS: • All FDG indices were significantly higher in malignant than in benign tumours. • All FLT indices were significantly higher in malignant than in benign tumours. • All FLT indices were significantly higher than those of FDG in AUC.

Correlations of (18)F-fluorothymidine uptake with pathological tumour size, Ki-67 and thymidine kinase 1 expressions in primary and metastatic lymph node colorectal cancer foci.

OBJECTIVE: To examine correlations of (18)F-fluorothymidine (FLT) uptake with pathological tumour size and immunohistochemical Ki-67, and thymidine kinase 1 (TK-1) expressions in primary and metastatic node colorectal cancer foci. METHODS: Thirty primary cancers (PCs) and 37 metastatic nodes (MNs) were included. FLT uptake was assessed by visual scores (non-visible: 0-1 and visible: 2-4), standardized uptake value (SUV), and correlated with size, Ki-67, and TK-1. SUV was measured in visible lesions. FLT heterogeneity was assessed by visual scores (no heterogeneous uptake: 0 and heterogeneous uptake: 1-4). RESULTS: Forty-two lesions were visible. The visible group showed significantly higher values than the non-visible group in size, Ki-67, and TK-1 (each p < 0.05). Size correlated significantly with visual score (PC; ρ = 0.74 and MN; ρ = 0.63), SUVmax (PC; ρ = 0.49, and MN; ρ = 0.76), and SUVmean (PC; ρ = 0.40 and MN; ρ = 0.76) (each p < 0.05). Visual score correlated significantly with size (ρ = 0.86), Ki-67max (ρ = 0.35), Ki-67mean (ρ = 0.38), TK-1max (ρ = 0.35) and TK-1mean (ρ = 0.25) (each p < 0.05). No significant correlations were found between FLT uptake and Ki-67 or TK-1 in 42 visible lesions (each p > 0.05). Heterogeneous FLT uptake was noted in 73 % (22/30) of PCs. CONCLUSION: FLT uptake correlated with size. Heterogeneous FLT distribution in colorectal cancers may be one of the causes of weak or lack of FLT uptake/Ki-67 or TK-1 correlation. KEY POINTS: FLT uptake correlated well with tumour size in colorectal cancer. Weak or lack of FLT uptake/Ki-67 and TK-1 correlations were observed. Immunohistochemical Ki-67 and TK-1 expressions are not always correlated with FLT uptake.

Imaging discrepancies between magnetic resonance imaging and brain perfusion single-photon emission computed tomography in the diagnosis of Alzheimer's disease, and verification with amyloid positron emission tomography.

BACKGROUND: In the diagnosis of Alzheimer's disease (AD), discrepancies are often observed between magnetic resonance imaging (MRI) and brain perfusion single-photon emission computed tomography (SPECT) findings. MRI, brain perfusion SPECT, and amyloid positron emission tomography (PET) findings were compared in patients with mild cognitive impairment or early AD to clarify the discrepancies between imaging modalities. METHODS: Several imaging markers were investigated, including the cortical average standardized uptake value ratio on amyloid PET, the Z-score of a voxel-based specific regional analysis system for AD on MRI, periventricular hyperintensity grade, deep white matter hyperintense signal grade, number of microbleeds, and three indicators of the easy Z-score imaging system for a specific SPECT volume-of-interest analysis. Based on the results of the regional analysis and the three indicators, we classified patients into four groups and then compared the results of amyloid PET, periventricular hyperintensity grade, deep white matter hyperintense signal grade, and the numbers of microbleeds among the groups. RESULTS: The amyloid deposition was the highest in the group that presented typical AD findings on both the regional analysis and the three indicators. The two groups that showed an imaging discrepancy between the regional analysis and the three indicators demonstrated intermediate amyloid deposition findings compared with the typical and atypical groups. The patients who showed hippocampal atrophy on the regional analysis and atypical AD findings using the three indicators were approximately 60% amyloid-negative. The mean periventricular hyperintensity grade was highest in the typical group. CONCLUSIONS: Patients showing discrepancies between MRI and SPECT demonstrated intermediate amyloid deposition findings compared with patients who showed typical or atypical findings. Strong white matter signal abnormalities on MRI in patients who presented typical AD findings provided further evidence for the involvement of vascular factors in AD.

Diagnostic performance of ¹8F-fluorothymidine PET/CT for primary colorectal cancer and its lymph node metastasis: comparison with ¹8F-fluorodeoxyglucose PET/CT.

PURPOSE: To examine the diagnostic performance of (18)F-fluorothymidine (FLT) PET/CT in primary and metastatic lymph node colorectal cancer foci in comparison with (18)F-fluorodeoxyglucose (FDG) PET/CT. METHODS: The study population comprised 28 patients with 30 newly diagnosed colorectal cancers who underwent surgical resection of the primary lesion and regional lymph nodes after both FLT and FDG PET/CT. The associations between SUVmax levels and pathological factors were evaluated using the Mann-Whitney U or Kruskal-Wallis test. Differences in diagnostic indexes for detecting nodal metastasis between the two tracers were estimated using the McNemar exact or χ(2) test. RESULTS: All 30 primary cancers (43.0 ± 20.0 mm, range 14 - 85 mm) were visualized by both tracers, but none of the FLT SUVmax values exceeded the FDG SUVmax values in any of the primary cancers (6.6 ± 2.4 vs. 13.6 ± 5.8, p < 0.001). The sensitivity, specificity and accuracy for detecting nodal metastasis were 41% (15/37), 98.8% (493/499) and 94.8% (508/536) for FDG PET/CT, and 32% (12/37), 98.8% (493/499) and 94.2% (505/536) for FLT PET/CT, respectively. The sensitivity (p = 0.45), specificity (p = 0.68) and accuracy (p = 0.58) were not different between the tracers. Nodal uptake of FLT and FDG was discordant in 7 (19%) of 37 metastatic nodes. There were ten concordant true-positive nodes of which six showed higher FDG SUVmax and four showed higher FLT SUVmax, but the difference between FDG and FLT SUVmax was not significant (5.56 ± 3.55 and 3.62 ± 1.45, respectively; p = 0.22). CONCLUSION: FLT has the same potential as FDG in PET/CT for the diagnosis of primary and nodal foci of colorectal cancer despite significantly lower FLT uptake in primary foci.

Diagnosis of metastases from postoperative differentiated thyroid cancer: comparison between FDG and FLT PET/CT studies.

PURPOSE: To compare positron emission tomography (PET)/computed tomography (CT) studies performed with the glucose analog fluorine 18 ((18)F) fluorodeoxyglucose (FDG) and the cell proliferation tracer (18)F fluorothymidine (FLT) in the diagnosis of metastases from postoperative differentiated thyroid cancer. MATERIALS AND METHODS: The institutional ethics review board approved this prospective study. From March 2010 to February 2012, 20 patients (mean age, 53 years; age range, 22-79 years) with postoperative differentiated thyroid cancer underwent both FDG and FLT PET/CT as a staging work-up before radioiodine therapy. In each patient, 28 anatomic areas were set and analyzed for lymph node and distant metastases. The McNemar exact or χ(2) test was used to examine differences in diagnostic indexes in the detection of lymph node and distant metastases between both tracer PET/CT studies. RESULTS: There were 34 lymph node metastases and/or 73 distant metastases (70 metastases in lung and one each in bone, nasopharynx, and brain) in 13 patients. At patient-based analysis, the sensitivity, specificity, and accuracy were 92% (12 of 13 patients), 86% (six of seven patients), and 90% (18 of 20 patients), respectively, for FDG PET/CT and 69% (nine of 13 patients), 29% (two of seven patients), and 55% (11 of 20 patients) for FLT PET/CT. The accuracy of FDG PET/CT was significantly better than that of FLT PET/CT (P = .023). At lesion-based analysis, the sensitivity, specificity, and accuracy for diagnosing lymph node metastases were 85% (29 of 34 lesions), 99.6% (245 of 246 lesions), and 97.9% (274 of 280 lesions), respectively, for FDG PET/CT and 50% (17 of 34 lesions), 90.7% (223 of 246 lesions), and 85.7% (240 of 280 lesions) for FLT PET/CT. The sensitivity, specificity, and accuracy for diagnosing distant metastases were 45% (33 of 73 lesions), 100% (207 of 207 lesions), and 85.7% (240 of 280 lesions), respectively, for FDG PET/CT and 6.8% (five of 73 lesions), 100% (207 of 207 lesions), and 75.7% (212 of 280 lesions) for FLT PET/CT. The sensitivity (P = .002), specificity (P < .001), and accuracy (P < .001) of FDG PET/CT in the diagnosis of lymph node metastases were superior to those of FLT PET, as were the sensitivity (P < .001) and accuracy (P < .001) in the diagnosis of distant metastases. CONCLUSION: FDG PET/CT is superior to FLT PET/CT in the diagnosis of postoperative differentiated thyroid cancer lymph node and distant metastases. Thus, FDG PET/CT is more suitable than FLT PET/CT for examining recurrence of postoperative differentiated thyroid cancer.

Clinical significance of ¹8F-fluorodeoxyglucose positron emission tomography in superficial esophageal squamous cell carcinoma.

PURPOSE: To assess the clinical usefulness and significance of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in superficial esophageal squamous cell carcinoma (ESCC). METHODS: We examined FDG-PET for 80 consecutive patients with superficial ESCC without neoadjuvant treatment. Fifty-seven patients underwent radical esophagectomy, and 23 patients received endoscopic resection. The FDG uptake index was evaluated with clinicopathological findings, and glucose transporter 1 (Glut-1) expression in primary tumors was examined immunohistochemically. RESULTS: The FDG uptake in primary tumors correlated with histology, depth of tumor invasion, lymph node metastasis, lymphatic invasion, vascular invasion, and Glut-1 expression. All patients with more than 4.4 maximum standardized uptake value (SUVmax) had deeper invasion of submucosa. Among 16 patients with lymph node metastasis, only two were found to have lymph node metastasis. FDG uptake, depth of tumor invasion, lymph node metastasis, and histology were found to be prognostic factors, and histology was an independent prognostic factor. In FDG uptake-positive patients, depth of tumor invasion and histology were prognostic factors. CONCLUSIONS: FDG-PET is useful for diagnosing tumors with deeper invasion of submucosa and is helpful in making decisions regarding endoscopic treatment for superficial ESCC. Patients with FDG uptake-positive disease, deeper invasion of submucosa, poorly differentiated tumor, and poor prognosis should receive multimodal treatment.

High FDG and low FLT uptake in a thyroid papillary carcinoma incidentally discovered by FDG PET/CT.

We report a 58-year-old man whose incidentally discovered papillary thyroid carcinoma in the left lobe showed high FDG and low FLT uptake on PET/CT. The SUVmax was 19.7 for FDG and 3.0 for FLT. The Ki-67 labeling index of the tumor was 1.9%. Thus, the low FLT uptake might be attributed to the low proliferative activity of this cancer.

FDG PET/CT and diffusion-weighted imaging of head and neck squamous cell carcinoma: comparison of prognostic significance between primary tumor standardized uptake value and apparent diffusion coefficient.

PURPOSE: To compare primary tumor (18)F-fluorodeoxyglucose (FDG) maximum standardized uptake value (SUV(max)) and diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) obtained in the same patients with head and neck squamous cell carcinoma (HNSCC) to clarify the prognostic significance of both indexes. MATERIALS AND METHODS: The study population comprised 26 patients with HNSCC visible on both pretreatment FDG PET/CT and DWI. Correlation between SUV(max) and ADC (b values; 0 and 800 seconds/mm(2)) was analyzed by the Spearman's rank test. Disease-free survival (DFS) was calculated by the Kaplan-Meier method. Prognostic significance was assessed by the long-rank test and Cox proportional hazards analysis. RESULTS: SUV(max) and ADC correlated significantly and negatively (ρ = -0.566, P = 0.005). High (>12.1) SUV(max) (P < 0.001), low (≤ 0.88) ADC (P = 0.009), high (T3-4) T stage (P = 0.030), and high (N2-3) N stage (P = 0.007) were significant in predicting poor 2-year DFS. The accuracy for predicting disease events was 81% (21/26) for SUV(max) (>12.1) and 73% (19/26) for ADC(≤ 0.88) without significant difference between them (P = 0.52). Disease event hazards ratios for significant unadjusted SUV(max) (P = 0.015) and ADC (P = 0.039) remained significant when adjusted for other dichotomized clinical covariates (SUV(max); P = 0.009-0.039, ADC; P = 0.017-0.037) except SUV(max) for ADC and ADC for SUV(max) and T stage. CONCLUSION: These results suggest that pretreatment primary tumor SUV(max) and ADC correlate significantly and negatively and both may have similar potential to predict DFS or disease events of HNSCC.