Advantages and limitations of 18-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography in the diagnosis of infective endocarditis

IntroductionThe early diagnosis of infective endocarditis (IE) is a medical challenge and a multidisciplinary approach is essential to improve its frequently fatal prognosis. Our goal was to evaluate the usefulness of [¹⁸F]2-fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸F-FDG PET) in the diagnosis of this disease.Materials and MethodsWe prospectively assessed 43 patients (five female and 38 male) with clinical suspicion of IE between 2014 and 2017. All patients underwent transesophageal echocardiography (TEE) and an ¹⁸F-FDG PET scan, and the results were compared. A positive PET finding was defined as increased FDG uptake on cardiac valves or intracardiac devices.ResultsOut of 43 patients with suspected IE, the diagnosis was confirmed in 30 cases (79.7%). ¹⁸F-FDG PET was positive in 24 patients, with 19 showing FDG uptake on cardiac valves (two native and 17 prosthetic) and five on cardiac devices, being concordant with echocardiographic findings in 11 cases. ¹⁸F-FDG PET sensitivity was 80%, specificity 92%, positive predictive value (PPV) 96% and negative predictive value (NPV) 66%. Echocardiography presented sensitivity, specificity, PPV and NPV of 36%, 84%, 84% and 36%, respectively.Conclusions¹⁸F-FDG PET proved to be a sensitive technique with a high diagnostic value in patients with prosthetic valves and intracardiac devices and suspected IE. Its utility decreased dramatically in patients with suspected IE on native valves, in which TEE presented higher sensitivity and thus better diagnostic value.     

Role of 18-fluoro-2-deoxyglucose positron emission tomography in detecting acute inflammatory lesions of non-bacterial osteitis in patients with a fever of unknown origin: A comparative study of 18-fluoro-2-deoxyglucose positron emission tomography,bone scan,and magnetic resonance imaging

Abstract

We report three patients with non-bacterial osteitis (NBO) who had fever of unknown origin (FUO) as an initial symptom. 18-Fluoro-2-deoxyglucose positron emission tomography (¹⁸F-FDG–PET) can be used to detect acute inflammatory lesions. There seems to be variation among the results of ¹⁸F-FDG–PET, a bone scan, and magnetic resonance imaging (MRI). Therefore, it would be useful to perform a bone scan to detect all lesions, combined with MRI to confirm the diagnosis of NBO, followed by ¹⁸F-FDG–PET.     

Diagnostic value for extrahepatic metastases of hepatocellular carcinoma in positron emission tomography/computed tomography scan

AIM: To evaluated the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) scan in diagnosis of hepatocellular carcinoma (HCC) and extrahepatic metastases.METHODS: A total of 138 patients with HCC who had both conventional imaging modalities and ¹⁸F-FDG PET/CT scan done between November 2006 and March 2011 were enrolled. Diagnostic value of each imaging modality for detection of extrahepatic metastases was evaluated. Clinical factors and tumor characteristics including PET imaging were analyzed as indicative factors for metastases by univariate and multivariate methods.RESULTS: The accuracy of chest CT was significantly superior compared with the accuracy of PET imaging for detecting lung metastases. The detection rate of metastatic pulmonary nodule ≥ 1 cm was 12/13 (92.3%), when < 1 cm was 2/10 (20%) in PET imaging. The accuracy of PET imaging was significantly superior compared with the accuracy of bone scan for detecting bone metastases. In multivariate analysis, increased tumor size (≥ 5 cm) (P = 0.042) and increased average standardized uptake value (SUV) uptake (P = 0.028) were predictive factors for extrahepatic metastases. Isometabolic HCC in PET imaging was inversely correlated in multivariate analysis (P = 0.035). According to the receiver operating characteristic curve, the optimal cutoff of average SUV to predict extrahepatic metastases was 3.4.CONCLUSION: ¹⁸F-FDG PET/CT scan is invaluable for detection of lung metastases larger than 1 cm and bone metastases. Primary HCC having larger than 5 cm and increased average SUV uptake more than 3.4 should be considered for extrahepatic metastases.     

Determination of optimum periods between onset of suspected acute myocarditis and F-fluorodeoxyglucose positron emission tomography in the diagnosis of inflammatory left ventricular myocardium

Purpose

To determine optimum periods for ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) examination in subjects with suspected acute myocarditis, we compared ¹⁸F-FDG PET with endomyocardial biopsy (EMB) using the latest definition of ¹⁸F-FDG PET for inflammatory left ventricular (LV) myocardium.

Materials and methods

Retrospective analysis of 29 subjects (18 male, 48 ± 18 years) who have symptoms or LV dysfunction underwent both ¹⁸F-FDG PET (Advance NXi, GE-Healthcare) under fasting conditions and EMB from LV posterior wall within 3 months.

Results

When we defined ¹⁸F-FDG PET positive inflammatory LV posterior wall as ‘focal on diffuse’ pattern, sensitivity, specificity, and positive predictive values (PPV), and negative predictive values (NPV) of ¹⁸F-FDG PET for detecting active inflammatory LV posterior wall compared with EMB were 46.2, 81.3, 66.7, and 65.0%, respectively. Receiver operating characteristic curve of periods (days) between onset of clinically suspected acute myocarditis and performance of ¹⁸F-FDG PET for detecting inflammatory LV posterior wall demonstrated 17 days as a best cut off values with area under the curve (0.497, P = 0.982) with sensitivity = 21.1% and specificity = 100%. Sensitivity, specificity, PPV and NPV of ¹⁸F-FDG PET for detecting inflammatory LV posterior wall on EMB were all 100% when ¹⁸F-FDG PET was performed at 1–14 days after onset of suspected acute myocarditis.

Conclusions

In our definition, ¹⁸F-FDG PET showed excellent agreement with EMB for detecting active inflammatory LV posterior wall in subjects with clinically suspected active acute myocarditis. If possible, ¹⁸F-FDG PET should be performed within 14 days after the onset to maintain high diagnostic accuracy compared with EMB.     

Clinical value of 18F-fluoro-dexoxyglucose positron emission tomography/computed tomography in patients with adult-onset Still's disease: A seven-case series and review of the literature

Abstract

Objectives. While there are a few reports describing 18F-fluoro-dexoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) findings in patients with adult-onset Still's disease (AOSD), no summary report has yet been published. In this study, we evaluated the usefulness of FDG-PET/CT for diagnosis and activity evaluation in patients with AOSD by summarizing the findings of our patients and those reported in the literature.

Methods. Seven consecutive AOSD patients who had undergone PET/CT at our department between 2007 and 2012 were included. We evaluated FDG uptake for characteristic findings in patients with AOSD. In addition, we reviewed the literature on seven previously reported AOSD patients who had undergone PET/CT.

Results. FDG accumulation was positive mainly in the bone marrow (100%), spleen (90.9%), lymph nodes (80.0%) and joints (75.0%). In addition, FDG uptake was positive in the pericardium, pleura, salivary glands, eyelids, muscle and major blood vessels. Six patients underwent follow-up FDG PET/CT for evaluation of treatment efficacy. Follow-up PET/CT showed diminished FDG accumulation in the bone marrow, spleen and lymph nodes, with maximum standardized uptake value (SUV_max) being substantially reduced from 4.03 ± 0.95 to 2.20 ± 0.75 (p = 0.04), 4.04 ± 1.10 to 2.55 ± 1.13 (p = 0.04) and 5.63 ± 4.99 to 2.10 ± 1.91 (p = 0.11), respectively. No significant correlation was found between SUV_max in each lesion and the laboratory data, except for a significant correlation between lactate dehydrogenase (LDH) and spleen SUV.

Conclusions. FDG-PET/CT is useful for long-term assessments of AOSD activity in individual patients. However, PET/CT findings alone are not sufficient to make a differential diagnosis of AOSD versus malignant lymphoma.     

Diagnostic accuracy of fluorine-18-fluorodeoxyglucose positron emission tomography in gallbladder cancer: A meta-analysis

AIM: To meta-analyze published data about the diagnostic accuracy of fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and PET/computed tomography (PET/CT) in the evaluation of primary tumor in patients with gallbladder cancer (GBCa).METHODS: A comprehensive literature search of studies published through 30^th June 2014 regarding the role of ¹⁸F-FDG PET and PET/CT in the evaluation of primary gallbladder cancer (GBCa) was performed. All retrieved studies were reviewed. Pooled sensitivity and specificity of ¹⁸F-FDG PET or PET/CT in the evaluation of primary GBCa were calculated. The area under the summary receiving operator characteristics curve (AUC) was calculated to measure the accuracy of these methods. Sub-analyses considering the device used (PET vs PET/CT) were carried out.RESULTS: Twenty-one studies comprising 495 patients who underwent ¹⁸F-FDG PET or PET/CT for suspicious GBCa were selected for the systematic review. The meta-analysis of 13 selected studies provided the following results: sensitivity 87% (95%CI: 82%-92%), specificity 78% (95%CI: 68%-86%). The AUC was 0.88. Improvement of sensitivity and specificity was observed when PET/CT was used.CONCLUSION: ¹⁸F-FDG-PET and PET/CT demonstrated to be useful diagnostic imaging methods in the assessment of primary tumor in GBCa patients, nevertheless possible sources of false-negative and false-positive results should be kept in mind. PET/CT seems to have a better diagnostic accuracy than PET alone in this setting.     

[18F]fluorodeoxyglucose positron emission tomography is a useful tool to diagnose the early stage of Takayasu's arteritis and to evaluate the activity of the disease

Abstract

Takayasu's arteritis (TA) is a rare disease that can be difficult to diagnose in its early stage. A young woman with a fever and neck pain was thought to have TA, although computed tomographic angiography did not show any specific changes of the arteries. [¹⁸F]fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG-PET) was performed to detect the source of the inflammation. Specific accumulation of [¹⁸F]FDG-6-phosphate in the thoracic aorta and its direct branches was observed, leading to a diagnosis of TA. [¹⁸F]FDG-PET is therefore considered to be useful for the diagnosis of early-stage TA.     

Positron emission tomography for the detection of colorectal adenomas

Background¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) has been reported to detect colorectal adenomas.AimsThis study aimed at evaluating the sensitivity of ¹⁸F-FDG PET with computed tomography image fusion (PET/CT) for detecting colorectal adenomas.MethodsWe retrospectively compared the results of 92 ¹⁸F-FDG PET/CT studies followed by colonoscopy. Colonoscopy and histology were considered as the gold standard.ResultsOne hundred fifty-seven lesions were observed. All the 12 malignancies were identified by ¹⁸F-FDG PET/CT but only 27 out of 119 resected adenomas (sensitivity 22.7%) and none of the hyperplastic polyps were detected. At the univariate and multivariate analyses there was a significant statistical association between adenomas sized more than 10 mm, presence of villous component and high-grade dysplasia and the ability of ¹⁸F-FDG PET/CT to detect adenomas. ¹⁸F-FDG PET/CT showed an overall sensitivity of 29.8%, a specificity of 81.1%, a positive predictive value (PPV) of 84.8% and a negative predictive value (NPV) of 24.6% for the neoplastic colorectal lesions globally considered.Conclusion¹⁸F-FDG PET/CT has a low sensitivity for detecting adenomas. However, because of the specificity and PPV of the technique for neoplastic colorectal lesions, the presence of a focal colorectal FDG uptake justifies the patient undergoing colonoscopy.     

Diagnostic performance of Fluorine-18-Fluorodeoxyglucose positron emission tomography in patients with chronic inflammatory bowel disease: A systematic review and a meta-analysis

ObjectiveTo systematically review and meta-analyze published data about the diagnostic performance of Fluorine-18-Fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and PET/computed tomography (PET/CT) in patients with chronic inflammatory bowel disease (IBD).MethodsA comprehensive computer literature search of studies published through May 2012 regarding ¹⁸F-FDG-PET and PET/CT in patients with IBD was performed. All retrieved studies were reviewed and qualitatively analyzed. Pooled sensitivity, specificity, positive and negative likelihood ratio (LR + and LR −) and diagnostic odd ratio (DOR) of ¹⁸F-FDG PET and PET/CT in patients with IBD on a per segment-based analysis were calculated. The area under the ROC curve was calculated to measure the accuracy of ¹⁸F-FDG PET and PET/CT in patients with IBD.ResultsNineteen studies comprising 454 patients with suspected IBD were included in the qualitative analysis (systematic review) and discussed. The quantitative analysis (meta-analysis) of seven selected studies (including 219 patients with IBD) provided the following results on a per segment-based analysis: sensitivity was 85% [95% confidence interval (95%CI) 81–88%], specificity 87% (95%CI 84–90%), LR + 6.19 (95%CI: 2.86–13.41), LR − 0.19 (95%CI: 0.10–0.34), and DOR 44.35 (95%CI: 11.77–167.07). The area under the ROC curve was 0.933.ConclusionsIn patients with suspected IBD ¹⁸F-FDG PET and PET/CT demonstrated good sensitivity and specificity, being accurate methods in this setting. Nevertheless, the literature focusing on the use of PET and PET/CT in IBD remains still limited; thus, further large multicenter studies will be necessary to substantiate the diagnostic accuracy of these methods in patients with IBD.     

Clinical application of 18F-fluorodeoxyglucose positron emission tomography for assessment and evaluation after therapy for malignant hepatic tumor

Positron emission tomography (PET) is widely available and its application with 2-[¹⁸F] fluoro-2-deoxy-d-glucose (¹⁸F-FDG) in oncology has become one of the standard imaging modalities in diagnosing and staging of tumors, and monitoring the therapeutic efficacy in hepatic malignancies. Recently, investigators have measured glucose utilization in liver tumors using ¹⁸F-FDG and positron emission tomography/computer tomography (PET/CT) in order to establish a diagnosis of tumors, assess their biologic characteristics and predict therapeutic effects on hepatic malignancies. The PET/CT with ¹⁸F-FDG may further enhance the hepatic malignancy diagnostic algorithm by accurate diagnosis, staging, restaging and evaluating its biological characteristics, which can benefit the patients suffering from primary and metastatic hepatic tumors such as hepatocellular carcinoma (HCC), cholangiocarcinoma (CCC), and metastatic liver tumor.     

Noninvasive prediction of tumor responses to gemcitabine using positron emission tomography

Gemcitabine (2′,2′-difluorodeoxycytidine, dFdC) and cytosine arabinoside (cytarabine, ara-C) represent a class of nucleoside analogs used in cancer chemotherapy. Administered as prodrugs, dFdC and ara-C are transported across cell membranes and are converted to cytotoxic derivatives through consecutive phosphorylation steps catalyzed by endogenous nucleoside kinases. Deoxycytidine kinase (DCK) controls the rate-limiting step in the activation cascade of dFdC and ara-C. DCK activity varies significantly among individuals and across different tumor types and is a critical determinant of tumor responses to these prodrugs. Current assays to measure DCK expression and activity require biopsy samples and are prone to sampling errors. Noninvasive methods that can detect DCK activity in tumor lesions throughout the body could circumvent these limitations. Here, we demonstrate an approach to detecting DCK activity in vivo by using positron emission tomography (PET) and ¹⁸F-labeled 1-(2′-deoxy-2′-fluoroarabinofuranosyl) cytosine] ([¹⁸F]FAC), a PET probe recently developed by our group. We show that [¹⁸F]FAC is a DCK substrate with an affinity similar to that of dFdC. In vitro, accumulation of [¹⁸F]FAC in murine and human leukemia cell lines is critically dependent on DCK activity and correlates with dFdC sensitivity. In mice, [¹⁸F]FAC accumulates selectively in DCK-positive vs. DCK-negative tumors, and [¹⁸F]FAC microPET scans can predict responses to dFdC. We suggest that [¹⁸F]FAC PET might be useful for guiding treatment decisions in certain cancers by enabling individualized chemotherapy.     

Fluorine-18 FDG positron emission tomography for imaging of hepatocellular carcinoma

OBJECTIVE: The detection of increased fluorine-18 fluorodeoxyglucose (18F-FDG) uptake by positron emission tomography (PET) is based on the enhanced glucose metabolism of tumor cells. Because the detection and staging of hepatocellular carcinoma (HCC) in patients with liver cirrhosis can be difficult, we prospectively evaluated the sensitivity of 18F-FDG PET in 14 consecutive patients with HCC. METHODS: Whole body and regional 18F-FDG PET of the liver were obtained. The results were compared with ultrasonography, contrast-enhanced, helical CT, histological grading, p53 protein expression of HCC, and serum alpha-fetoprotein (AFP) level. RESULTS: In 7 patients PET demonstrated increased tumor 18F-FDG uptake, whereas HCC was not distinguishable from nonmalignant liver tissue in 7 other patients. Hepatic lesions were detected by ultrasonography in all patients, whereas only 11 of 14 HCCs could be identified by CT. In 3 patients extrahepatic spread was demonstrated by 18F-FDG PET. Patients with increased tumor 18F-FDG uptake had significantly larger hepatic lesions and higher serum AFP levels than those with normal 18F-FDG uptake. Lesions could be visualized by 18F-FDG PET in 7 of 8 patients with moderately or poorly differentiated HCC, whereas none of the six well-differentiated tumors was detected. Two patients with strong p53 expression demonstrated increased tumor 18F-FDG uptake and extrahepatic metastases. CONCLUSIONS: The sensitivity of 18F-FDG PET for the imaging of HCC is low. Nevertheless, in patients with moderately or poorly differentiated HCC, tumors >5 cm, or with markedly elevated AFP levels 18F-FDG PET may contribute to an effective noninvasive staging.     

Use of 18F-fluoride positron emission tomography as a predictor of the hip osteoarthritis progression

Objective. The prediction of hip osteoarthritis (OA) progression is still a difficult issue. We have adopted ¹⁸F-fluoride positron emission tomography (PET) for the evaluation of hip osteoarthritis, and investigated the prediction utility of ¹⁸F-fluoride PET for both pain worsening and OA progression using a logistic regression model.

Materials and methods. A total of 57 hip joints were analyzed for progression risk factors for pain worsening and minimum joint space (MJS) narrowing by logistic regression analysis. Sex, age, BMI, existence of pain, the PET maximum standardized uptake value (SUV_max), Kellgren and Lawrence grade, MJS, and follow-up period were used as explanatory variables. Receiver operating characteristic analysis was performed to calculate the cutoff value of the SUV_max.

Results. Multivariate logistic regression analysis revealed significant differences only in the SUV_max values for pain worsening and MJS narrowing. The odds ratio of the SUV_max for pain worsening was 1.89, and for MJS narrowing it was 11.02. The SUV_max cutoff value was 7.2 (sensitivity: 1.00, specificity: 0.84) for pain worsening and 6.4 (sensitivity: 0.92, specificity: 0.83) for MJS narrowing.

Conclusions. Our results indicate that the PET SUV_max is a best predictor of pain worsening and MJS narrowing. This imaging modality has a great potential for the prediction of OA progression.     

Hypertrophic spinal pachymeningitis caused by ANCA-associated vasculitis revealed by 18F-FDG PET/CT: A case report

Rationale:Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) can involve the central nervous system in estimatedly 15% of patients. Hypertrophic pachymeningitis causes inflammatory hypertrophy of the cranial or spinal dura mater and patients present with various neurological deficits. ANCA-associated hypertrophic spinal pachymeningitis has rarely been reported in literature. We report a case of AAV presenting with hypertrophic spinal pachymeningitis detected by ¹⁸F-FDG PET/CT.Patient concerns:A 66-year-old woman diagnosed with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis developed back pain, bilateral lower limb weakness, dysuria, and dysporia 1 month ago.Diagnosis:Contrast-enhanced MRI showed thickening and enhancement of the dura mater in the thoracic cord. Intraspinal hypermetabolism in the corresponding region was observed on ¹⁸F-FDG PET/CT. The patient was finally diagnosed with ANCA-associated hypertrophic spinal pachymeningitis.Interventions:The patient was treated with a higher dose of prednisone and cyclophosphamide.Outcomes:After 2-week treatment, the patient''s neurological symptoms improved rapidly and laboratory findings were ameliorated. A repeated contrast-enhanced MRI showed partial improvement of the disease in the thoracic cord.Lessons:¹⁸F-FDG PET/CT and contrast-enhanced MRI can aid in the clinical diagnosis and surveillance in AAV-associated hypertrophic spinal pachymeningitis and potentially facilitate early recognition and intervention to prevent irreversible neurological impairment.     

Metabolic restaging of hepatocellular carcinoma using whole-body 18F-FDG PET/CT

AIM: To evaluate the ability of ¹⁸F-fluorodeoxyglucose positron emission and computed tomography (¹⁸F-FDG PET/CT) in restaging of hepatocellular carcinoma (HCC) after treatment.METHODS: We reviewed a database of the diagnostic performance of ¹⁸F-FDG PET/CT scan for patients with HCC following local or regional treatment. The database consisted of ¹⁸F-FDG PET/CT information of 21 male and 4 female (age range, 27-81 years; mean age, 51.6 years) patients who had received surgical resection and/or interventional treatments and then underwent ¹⁸F-FDG PET/CT scan. All patients had received enhanced CT scan of the liver two weeks before or after the ¹⁸F-FDG PET/CT scan. Intrahepatic recurrence and/or extrahepatic metastases were confirmed by histological analysis or clinical and imaging follow-up. The accuracy of ¹⁸F-FDG PET/CT study was determined by histopathological results or by clinical and imaging follow-up.RESULTS: ¹⁸F-FDG PET/CT was abnormal in 19 of the 25 (76.0%) patients. In detecting HCC recurrence, ¹⁸F-FDG PET/CT scored 17 true positives, 5 true negatives, 2 false positives and 1 false negative. The sensitivity, specificity and accuracy of ¹⁸F-FDG PET/CT in detecting HCC recurrence was 89.5%, 83.3% and 88%, respectively. ¹⁸F-FDG PET/CT had an impact on management of these patients by settling the problem of an unexplained increase in alpha-fetoprotein after treatment (14 patients), by monitoring response to the treatment and guiding additional regional therapy (12 patients), by identifying extrahepatic metastases (10 patients), by identifying tumor growth or thrombosis in the portal vein (6 patients), or by guiding surgical resection of extrahepatic metastases (2 patients).CONCLUSION: Our results suggest that whole body ¹⁸F-FDG PET/CT may be useful in the early evaluation of residual, intrahepatic recurrent or extrahepatic metastatic lesions and able to provide valuable information for the management of HCC recurrence.     

Clinical impact of 11C-Pittsburgh compound-B positron emission tomography in addition to magnetic resonance imaging and single-photon emission computed tomography on diagnosis of mild cognitive impairment to Alzheimer's disease

This study aimed to evaluated the clinical impact of adding [¹¹C] Pittsburgh compound-B (¹¹C-PiB) PET for clinical diagnosis of mild cognitive impairment (MCI) to Alzheimer''s disease (AD) dementia.Twenty six (mean age 78.5 ± 5.18 years, 21 females) AD (n = 7), amnestic MCI (n = 12), non-amnestic MCI (n = 3), vascular dementia, progressive supranuclear palsy (PSP) with frontotemporal dementia (FTD), FTD (n = 1 each), and normal (n = 1) patients underwent ¹¹C-PiB-PET, MRI, and SPECT scanning. ¹¹C-PiB-PET was compared with MRI and SPECT for clinical impact.¹¹C-PiB-PET showed positivity in 6, 9, and 0 of the AD, amnestic MCI, and non-amnestic MCI patients, respectively, and 0 of those with another disease. Parahippocampal atrophy at VSASD was observed in 5 AD patients, 6 amnestic and PiB-positive MCI patients, 1 amnestic and PiB-negative MCI patient, and 1 vascular dementia patient. Parietal lobe hypoperfusion in SPECT findings was observed in 6, 4, and 2 of those, respectively, as well as 1 each of non-amnestic MCI, vascular dementia, and normal cases. Sensitivity/specificity/accuracy for selecting PiB-positive patients among the 15 MCI patients for ¹¹C-PiB-PET were 100% (9/9)/100% (6/6)/100% (15/15), for VSRAD were 66.7% (6/9)/83.3% (5/6)/73.3% (11/15), and for SPECT were 44.4% (4/9)/50.0% (3/6)/46.7% (7/15), while those were 88.9% (8/9)/33.3% (2/6)/66.7% (10/15)/for combined VSRAD and SPECT. ¹¹C-PiB-PET accuracy was significantly higher than that of SPECT.¹¹PiB-PET alone may be useful for selecting patients who will progress from MCI to AD in the future, although follow-up study is necessary to clarify the outcome of MCI patients.     

A case of adult-onset Still’s disease (AOSD)-like manifestations abruptly developing during confirmation of a diagnosis of metastatic papillary thyroid carcinoma

Abstract

A 68-year-old Japanese man was admitted to our hospital suffering from abrupt onset of high fever accompanied by arthralgia, myalgia, sore throat, macular eruption, and liver dysfunction. Six months before the onset of these manifestations, ¹⁸F-fluoro-deoxy-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) had detected, unexpectedly, three calcified thyroid lesions without ¹⁸F-FDG uptake. Two months before the onset of the present manifestations, ultrasonography-guided fine-needle aspiration had led to a diagnosis of papillary thyroid carcinoma (PTC). Soon after the occurrence of the rheumatic manifestations, a subsequent ¹⁸F-FDG PET/CT scan showed not only the three thyroid lesions, the same as those in the previous scan, but also ¹⁸F-FDG uptake in the thyroid lesion. A diagnosis of adult-onset Still’s disease (AOSD)-like manifestations associated with PTC was made, and treatment with 40 mg/day of prednisolone (PSL) resolved the symptoms promptly. PSL was gradually tapered, without recurrence of the (AOSD)-like manifestations. Five months after the initiation of treatment with PSL, total thyroidectomy, followed by ¹³¹I thyroid ablation treatment, was performed while the patient was on a PSL dose of 18 mg/day. Seven months after the thyroidectomy, the dose of PSL was tapered to 2 mg/day, and neither the AOSD-like manifestations nor the PTC relapsed. On confirming a diagnosis of AOSD, it may be necessary to consider the presence of an associated malignancy, including solid tumors such as PTC.     

Early detection of cardiac sarcoid lesions with (18)F-fluoro-2-deoxyglucose positron emission tomography

In April 2005, a 72-year-old woman with pulmonary sarcoidosis exhibited focal (18)F-fluoro-2-deoxyglucose ((18)F-FDG) uptake in her heart on (18)F-FDG positron emission tomography (PET). Although Japanese guidelines for diagnosing cardiac sarcoidosis were not met at this point, electrocardiography, echocardiography, and magnetic resonance imaging became diagnostic for cardiac sarcoidosis 1 year later. In the present case report, the potential of (18)F-FDG PET in the early recognition of cardiac sarcoidosis in comparison with other imaging modalities is discussed.     

Diagnosis and evaluation of gastric cancer by positron emission tomography

Gastric cancer is the second leading cause of cancer mortality worldwide.The diagnosis of gastric cancer has been significantly improved with the broad availability of gastrointestinal endoscopy.Effective technologies for accurate staging and quantitative evaluation are still in demand to merit reasonable treatment and better prognosis for the patients presented with advanced disease.Preoperative staging using conventional imaging tools,such as computed tomography(CT)and endoscopic ultrasonography,is inadequate.Positron emission tomography(PET),using 18F-fluorodeoxyglucose(FDG)as a tracer and integrating CT for anatomic localization,holds a promise to detect unsuspected metastasis and has been extensively used in a variety of malignancies.However,the value of FDG PET/CT in diagnosis and evaluation of gastric cancer is still controversial.This article reviews the current literature in diagnosis,staging,response evaluation,and relapse monitoring of gastric cancer,and discusses the current understanding,improvement,and future prospects in this area.     

Role of 18F-fluorodeoxyglucose positron emission tomography in preoperative assessment of cytologically indeterminate thyroid nodules

OBJECTIVE: The objective of the study was to determine the diagnostic accuracy of (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) in the preoperative diagnosis of thyroid nodules with indeterminate fine-needle aspiration biopsy results. METHODS: Forty-two consecutive patients with thyroid nodules with indeterminate cytological results participated in this study. Abnormal (18)F-FDG PET uptake was assessed visually and by measuring the maximum standardized uptake value (SUVmax) in thyroid topography. All these results were compared with the final pathological results. RESULTS: The presence of focal uptake correlated with a greater risk of malignancy (P = 0.018). All 11 malignant nodules had focal uptake (sensitivity of 100%). Of the 31 patients with benign nodules, there were 19 with positive uptake (specificity of 38.7%). The pre-PET probability of cancer was 26.2% (11 of 42), and this probability increased to 36.7% after PET for those patients whose exam showed focal uptake (11 of 30). The preoperative use of (18)F-FDG PET would result in a significant reduction (39%, 12 of 31) in the number of thyroidectomies performed in patients with benign lesions. SUVmax could not improve this degree of accuracy. There was no correlation between thyroid nodule size and SUVmax value (P = 0.96). Patients with carcinomas were younger than patients with benign lesions (P = 0.048). There was no other clinical, laboratory, or ultrasonographic variable related to malignancy. CONCLUSIONS: (18)F-FDG PET provides high sensitivity to malignant lesions and may be a potentially useful tool in the evaluation of thyroid nodules with indeterminate cytological findings. For these nodules the number of unnecessary thyroidectomies in a hypothetical algorithm using (18)F-FDG PET would be reduced by 39%.