Underwent FDG Positron Emission Tomography Research Articles

Left atrial glucose metabolism by 18F-FDG PET/CT in persistent atrial fibrillation and after return to sinus rhythm

Abstract Background Atrial Fibrillation (AF) is strongly associated with the development of Left Atrial (LA) remodeling. Animal studies pointed to an important role of metabolic deregulation in AF, yet few studies have assessed LA myocardial metabolism in vivo in patients with AF. 18-fluorodeoxyglucose (FDG) Positron Emission tomography (PET) has been widely used for evaluation of left ventricular (LV) metabolism, but its application to study metabolism of LA has not yet been explored. Purpose The aim of this study was to evaluate LA glucose metabolism and contractile efficiency in patients with persistent AF, following our successful implementation of a protocol enabling the acquisition of high-resolution PET images of the LA. Methods 36 nondiabetic patients (64±7 years, 29 men) with persistent non valvular AF (peAF) undergoing a first AF ablation and 5 healthy age matched volunteers (69±5 years, 3 men, p=0.114) without AF underwent FDG PET, speckle tracking echocardiography (STE) and cardiac MRI (cMR). PET was performed after overnight fasting and after administration of a nicotinic acid derivative (Acipimox 250 mg) to maximally stimulate myocardial glucose uptake. The 3 tests were repeated 3 months later in 26 patients in whom return to permanent sinus rhythm (SR) could be obtained after the ablation procedure. PET images were registered with cMR LA angiography, and the mean partial volume and spillover corrected standardized FDG uptake (SUV) in the whole LA, the left atrial appendage (LAA), and the left ventricle (LV) were computed. Measurements were compared to global Peak Atrial Longitudinal Strain (GPALS) and to left atrial ejection fraction (LAEF) measured by STE and LA contractile efficiency was computed as the ratio of LA SUV to LAEF. Results Hemodynamics (syst. BP mmHg: 128±11 vs 129±5 mmHg, p=0.663) and metabolic parameters (glycemia: 99±14 vs 96±7 mg/dl, p=0.480) were similar in peAF patients and healthy controls. While 18F-FDG SUV in the LV was comparable between pEAF patients and healthy controls, patients in peAF exhibited significantly increased SUV in LA and LAA compared to controls. Following a return to SR, LA-SUVmean and LAA-SUVmean in patients peAF decreased significantly after 3 months (20.3%, p<0.002 and 34.1%, p<0.001), whereas the LV-SUVmean remained unchanged (p=0.847). The Global Peak Atrial Longitudinal Strain (GPALS) increased by 54.2%(p<0.001), and the Left Atrial Ejection Fraction (LAEF) by 39.2% (p<0.001), post-restoration of SR. (Figure 1). Accordingly contractile efficiency of LA SUV/LAEF in peAF patients improved significantly upon their return to SR (47%, p<0.001). Conclusion LA glucose metabolism is significantly increased in peAF and return after restoration of SR. This could indicate oxygen wasting and reduced contractile efficiency of AF or metabolic shift towards preferred glucose metabolism in AF. These findings support the notion that LA glucose metabolism plays a role in the pathophysiology of AF.Figure 1Figure 2

Prediction of Early-stage Liver Fibrosis Using FDG-PET/CT.

18F-fluorodeoxyglucose (FDG) is known to accumulate in the liver. We investigated whether accumulation of FDG was correlated with the degree of liver fibrosis and the grade of necro-inflammatory activity. This retrospective study included 35 patients who underwent FDG-positron emission tomography (PET)/computed tomography (CT) before liver surgery. On fusion images of CT and PET, by placing regions of interest on the lateral, anterior and posterior segments of the liver and the aorta, the standardized uptake value (SUV) mean, and SUV normalized by lean body mass (SUL) mean of the liver were measured, and the ratio SUVmean liver/SUVmean aorta was calculated. According to the New Inuyama Classification, subjects were classified into three groups based on the grade of liver-fibrosis degree, i.e., F0, F1+F2 and F3+F4, and into three groups based on the grade of necro-inflammatory activity, i.e., A0, A1 and A2. Each of the above parameters was then compared among the groups using a Tukey test. Average SULmean liver values of the F0, F1+F2 and F3+F4 groups were 1.573±0.211, 1.845±0.220 and 1.716±0.119, respectively. The SULmean liver of the F1+F2 group was significantly higher than that of the F0 group (p=0.0296). No significant difference was observed for the other two parameters. None of the parameters exhibited significant difference among the A0, A1, and A2 groups. FDG accumulation in the liver may be increased in the early stage of liver fibrosis. SULmean liver could be used to determine the necessity for therapeutic intervention in chronic liver disease.

A design of forceps-type coincidence radiation detector for intraoperative LN diagnosis: clinical impact estimated from LNs data of 20 esophageal cancer patients

PurposeTo reduce postoperative complications, intraoperative lymph node (LN) diagnosis with 18F-fluoro-2-deoxy-D-glucose (FDG) is expected to optimize the extent of LN dissection, leading to less invasive surgery. However, such a diagnostic device has not yet been realized. We proposed the concept of coincidence detection wherein a pair of scintillation crystals formed the head of the forceps. To estimate the clinical impact of this detector, we determined the cut-off value using FDG as a marker for intraoperative LN diagnosis in patients with esophageal cancer, the specifications needed for the detector, and its feasibility using numerical simulation.MethodsWe investigated the dataset including pathological diagnosis and radioactivity of 1073 LNs resected from 20 patients who underwent FDG-positron emission tomography followed by surgery for esophageal cancer on the same day. The specifications for the detector were determined assuming that it should measure 100 counts (less than 10% statistical error) or more within the intraoperative measurement time of 30 s. The detector sensitivity was estimated using GEANT4 simulation and the expected diagnostic ability was calculated.ResultsThe cut-off value was 620 Bq for intraoperative LN diagnosis. The simulation study showed that the detector had a radiation detection sensitivity of 0.96%, which was better than the estimated specification needed for the detector. Among the 1035 non-metastatic LNs, 815 were below the cut-off value.ConclusionThe forceps-type coincidence detector can provide sufficient sensitivity for intraoperative LN diagnosis. Approximately 80% of the prophylactic LN dissections in esophageal cancer can be avoided using this detector.

Physiological 2-deoxy-2-[fluorine-18] fluoro-D-glucose accumulation in the thenar eminence in adults: a single-center retrospective study.

This study evaluated the frequency, and effect of physiological 2-deoxy-2-[fluorine-18] fluoro-D-glucose (FDG) tracer injection and its association with the penetration rates of mobile devices. This retrospective analysis included 213 patients (mean age ± standard deviation, 66.2 ± 14.1years; range 23-93years; 125 men) who underwent FDG-positron emission tomography examination. Elevated FDG activity in the thenar eminence with maximum standardized uptake value (SUVmax) ≥ 2.5 was considered positive. Differences according to age, sex, laterality, and tracer injection side were evaluated using Fisher's exact test. Associations were assessed using Pearson's correlation coefficient. Twenty-three percent (49/213) of the patients had elevated FDG activity in the thenar eminence (mean SUVmax, 3.50 ± 1.04; range 2.5-6.3), including 18 with bilateral findings. No significant difference existed according to age (< 50years vs. 50-69years vs. ≥ 70years), sex, laterality, or tracer injection side. No significant correlation existed between penetration rates of mobile devices and the findings (p = 0.08). Elevated FDG activity in the thenar eminence occurs in adults, regardless of age, sex, laterality, or tracer injection side. This should be considered a common physiological change that does not warrant any further investigation.

Differential Diagnosis of Parkinsonism with Deep Metabolic Imaging Biomarker – An Artificial Intelligence-Aided Multi-Cohort FDG PET Study

Background: The clinical presentation of early idiopathic Parkinson’s disease (IPD) substantially overlaps with that of atypical parkinsonian syndromes such as multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has proven useful in assisting in the differential diagnosis of these parkinsonian syndromes. The aim of this study was to develop a metabolic imaging biomarker based on deep learning to support the differential diagnosis of parkinsonism. Methods: In addition to 863 non-parkinsonian subjects, a total of 1275 parkinsonian patients were accessed who underwent FDG PET imaging, clinical evaluation, and follow-up, yielding clinically possible, definite, or confirmative diagnoses of IPD, MSA, and PSP. A 3D deep convolutional neural network was developed to extract a deep metabolic imaging (DMI) biomarker. The accuracy of the DMI biomarker was evaluated with a cross-validation and a blind test. The robustness of the DMI biomarker was assessed on patients with longitudinal follow-up. The functional basis of DMI biomarker was further investigated based on the saliency map of the obtained deep neural network. Findings: The proposed DMI biomarker achieved an area under the receiver operating characteristic curve of 0·986 for the differential diagnosis of IPD, 0·997 for MSA, and 0·982 for PSP in the cross-validation. In the blind test, the DMI biomarker resulted in sensitivities of 98·1%, 88·5%, and 84·5%, as well as specificities of 90·0%, 99·2%, and 97·8% for IPD, MSA, and PSP respectively. The integration of demographic information and clinical assessments to DMI biomarker resulted in slight improvements. Saliencies for the DMI biomarker were found in several parkinsonism-related regions such as midbrain, putamen, and cerebellum. Interpretation: The DMI biomarker based on deep learning shows potential to provide accurate differential diagnosis for parkinsonism on FDG PET. The functional regions behind the DMI biomarker are consistent with known parkinsonian pathology. Funding Statement: The work was supported by grants from the National Natural Science Foundation of China (No. 81771483, 81671239, 81361120393, 81401135, 81971641, 81902282, 91949118, 81771372), from the Ministry of Science and Technology of China (2016YFC1306504), Shanghai Municipal Science and Technology Major Project (No. 2017SHZDZX01, 2018SHZDZX03) and ZJ Lab, Shanghai Sailing Program (No. 18YF1403100). It was also supported by Swiss National Science Foundation (No. 188350) and Siemens Healthineers. Declaration of Interests: W.H.O is Hertie Senior Research Professor, supported by the Charitable Hertie Foundation, Frankfurt/Main, Germany. A.R. and K.S. received research support from Siemens Healthineer. Other authors report no financial interests or potential conflicts of interest regarding the subject matter of the manuscript. Ethics Approval Statement: All procedures performed in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. All the data were from Parkinson's Disease Database and Samples Bank in Huashan Hospital. Ethics permission was obtained from the Institutional Review Board of Huashan Hospital and written consent was obtained from each subject after detailed explanation of the procedures.

Evaluation of renal cell carcinoma histological subtype and fuhrman grade using 18F-fluorodeoxyglucose-positron emission tomography/computed tomography.

We evaluated 18F-fluorodeoxyglucose (FDG) uptake by renal cell carcinomas (RCCs) to determine whether different histological subtypes and Fuhrman grades can be distinguished. We retrospectively reviewed the records and maximum standardised uptake value (SUVmax) of 147 patients with 154 RCCs who underwent FDG-positron emission tomography (PET)/computed tomography (CT) prior to tumour resection. The SUVmax was significantly lower in chromophobe RCC (chRCC) tumours than in clear cell RCC (ccRCC; p = 0.003) and papillary RCC (pRCC; p = 0.034) tumours. The mean tumour SUVmax was 4.58 ± 4.1 (range, 1.29-30.4) for ccRCC, 3.98 ± 1.9 (range, 0.49-6.72) for pRCC, and 1.93 ± 0.9 (range, 0.89-3.41) for chRCC. The SUVmax was not significantly different between the ccRCC and pRCC groups. In ccRCC and pRCC tumours, high-grade tumours had a significantly greater SUVmax (p < 0.001 and p < 0.05) than low-grade tumours by analysis of variance (ANOVA) and the Mann-Whitney U test. In ccRCC, multivariate regression analysis indicated that the SUVmax was a significant indicator of Fuhrman grade. No significant differences in uptake were observed between high- and low-grade chRCC tumours. The SUVmax obtained using FDG-PET/CT may be an important indicator for predicting tumour grade in ccRCC and pRCC. • FDG accumulation reflects tumour aggressiveness and correlates with Fuhrman grade. • FDG-PET/CT enables the differentiation of high- and low-grade ccRCC and pRCCs. • FDG-PET/CT may valuable in the identification of some high-grade RCCs.

Repeated Positron Emission Tomography-Computed Tomography and Perfusion-Computed Tomography Imaging in Rectal Cancer: Fluorodeoxyglucose Uptake Corresponds With Tumor Perfusion

The purpose of this study was to analyze both the intratumoral fluorodeoxyglucose (FDG) uptake and perfusion within rectal tumors before and after hypofractionated radiotherapy. Rectal cancer patients, referred for preoperative hypofractionated radiotherapy (RT), underwent FDG-positron emission tomography (PET)-computed tomography (CT) and perfusion-CT (pCT) imaging before the start of hypofractionated RT and at the day of the last RT fraction. The pCT-images were analyzed using the extended Kety model, quantifying tumor perfusion with the pharmacokinetic parameters K(trans), v(e), and v(p). The mean and maximum FDG uptake based on the standardized uptake value (SUV) and transfer constant (K(trans)) within the tumor were correlated. Also, the tumor was subdivided into eight subregions and for each subregion the mean and maximum SUVs and K(trans) values were assessed and correlated. Furthermore, the mean FDG uptake in voxels presenting with the lowest 25% of perfusion was compared with the FDG uptake in the voxels with the 25% highest perfusion. The mean and maximum K(trans) values were positively correlated with the corresponding SUVs (ρ = 0.596, p = 0.001 and ρ = 0.779, p < 0.001). Also, positive correlations were found for K(trans) values and SUVs within the subregions (mean, ρ = 0.413, p < 0.001; and max, ρ = 0.540, p < 0.001). The mean FDG uptake in the 25% highest-perfused tumor regions was significantly higher compared with the 25% lowest-perfused regions (10.6% ± 5.1%, p = 0.017). During hypofractionated radiotherapy, stable mean (p = 0.379) and maximum (p = 0.280) FDG uptake levels were found, whereas the mean (p = 0.040) and maximum (p = 0.003) K(trans) values were found to significantly increase. Highly perfused rectal tumors presented with higher FDG-uptake levels compared with relatively low perfused tumors. Also, intratumor regions with a high FDG uptake demonstrated with higher levels of perfusion than regions with a relatively low FDG-uptake. Early after hypofractionated RT, stable FDG uptake levels were found, whereas tumor perfusion was found to significantly increase.

Abstract P5-01-09: Evaluation of Tumor Blood Flow with Dynamic 18F-Fluorodeoxyglucose Positron Emission Tomography: Correlation with Microvessel Density

Abstract Background: Breast cancer is typically associated with an increase in tumor blood flow (due to angiogenesis) and tumor metabolism. Thus, these 2 key parameters are essential to characterize aggressiveness of breast tumors. Moreover, angiogenesis is a potential target for specific therapies. Positron Emission Tomography (PET) with 18F-Fluorodeoxyglucose (FDG) has become the gold standard for in vivo evaluation of tumor metabolism. A method for simultaneous measurement of blood flow and metabolism from a single injection of FDG may be an important addition for functional imaging of breast tumors. Unfortunately, there is no consensus on the validity of dynamic FDG acquisition for the evaluation of tumor blood flow. Objective: to compare a new technique for simultaneous evaluation of tumor blood flow and metabolism, using a dynamic acquisition of FDG PET, with proliferation and endothelial cell markers. Material and methods: Twenty-eight patients with new diagnosed locally advanced breast cancer were included. In addition to diagnosis and tumor grading, biopsy samples of each tumor were used to assess the Ki-67 index of proliferation and the immuno-staining for CD31 (a panendothelial cell marker) and CD105 (a proliferation-related endothelial cell marker) (both expressed as number of labeled vessels counted on 10 consecutive high power fields, 400X magnification). All patients underwent FDG PET at least one week after sample biopsy and before any treatment. Dynamic 2 minutes acquisition was performed immediately after intravenous injection of 5 MBq/Kg of FDG; tumor Blood Flow (BF, in ml/min/g) was then calculated using a single compartiment kinetic model. Static acquisition was performed 60 minutes after injection for quantification of delayed FDG tumor uptake (“Standardized Uptake Value”, SUV), reflecting tumor metabolism. Results: Pathologic and PET data were available for all patients. The SUV measured on delayed PET images was strongly positively correlated with the expression of Ki-67 (r=+0.693; P&amp;lt;0.0001). In contrast, there was no significant correlation between SUV and endothelial markers (CD31 and CD105). Tumor BF was positively correlated with the expression of CD31 (r=+0.392; p=0.039) and CD105 (r=+0.470; p=0.016). In contrast, there was no significant correlation between BF and Ki-67. Patients were categorized according to low (inframedian) or high (supramedian) tumor BF. Patients with high tumor BF showed a higher mean CD31 expression (236±169 vs 124±47, p=0.025) and a higher mean CD105 expression (110±73 vs 51±14; p=0.006) when compared with low tumor BF. In contrast there was no significant difference concerning SUV and Ki-67. Conclusion: Tumor BF quantified by dynamic FDG PET is related to tumor microvessel density evaluated by immunohistochemistry. Thus, dynamic FDG PET is a valuable tool to evaluate both tumor blood flow and metabolism. Further investigations are needed to confirm the respective role of these 2 key parameters for elaboration of therapeutic strategies and response assessment in locally advanced breast cancer. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-01-09.

Complete response to preoperative chemoradiotherapy in highly advanced gastric adenocarcinoma

This report presents a case of highly advanced gastric cancer that achieved a histologically complete response (CR) to preoperative chemoradiotherapy with S-1 plus low-dose Cisplatin. A 60-year-old male patient underwent FDG positron emission tomography (PET) during a routine health examination. The patient was found to have swollen paraaortic lymph nodes. Shortly thereafter, he was diagnosed with gastric carcinoma with a type 2 tumor in the antrum with paraaortic lymph node metastases based on FDG-PET, endoscopic examination and abdominal computed tomography. After the completion of chemoradiation therapy (CRT), the tumor and the paraaortic lymph node metastases disappeared. The patient underwent surgery 5 wk after the completion of CRT, including a subtotal gastrectomy with Roux-en-Y reconstruction, D3 lymph node dissection and a left adrenalectomy. No cancer cells were detected in the resected specimen either in the primary lesion or lymph nodes, thus confirming a pathologically CR to CRT (CR grade 3). The patient has been stable and well without any evidence of recurrence for 48 mo after surgery. Such a preoperative CRT regimen might therefore be very effective for treatment of some advanced gastric cancers.

Usefulness of FDG-PET/CT in the detection of pancreatic metastases from lung cancer

The objective of this study was to assess the ability to detect pancreatic metastasis of lung cancer and to clarify the degree of fluorodeoxyglucose (FDG) accumulation and computed tomography (CT) characteristics of pancreatic metastasis from lung cancer. A total of 573 patients (415 men and 158 women) with lung cancer were retrospectively evaluated. All patients underwent FDG-positron emission tomography (PET)/CT with contrast-enhanced CT for first=stage (313 patients; initial study group) or follow-up study (260 patients; follow-up study group). A lesion was regarded as positive for metastasis on the basis of visual judgment of the degree of increased metabolism by two experienced and independent interpreters, supported by semiquantitative evaluation on the basis of calculation of the maximum standardized uptake value (SUV(max)). Abnormal accumulations in the pancreas were detected in 5 of 313 patients (1.60%) in the initial study group, and 6 of 260 patients (2.31%) in the follow-up study group. Seven of these patients had adenocarcinoma, three had small cell carcinoma, and the rest had large cell endocrine carcinoma. Tumor sizes (longitudinal diameter), measured by CT, of these 11 patients ranged from 6 mm to 52 mm (mean +/- SD 8.3 mm +/- 11.9 mm), and SUV(max) for 1 h ranged from 3.37 to 11.1 (mean +/- SD 6.12 +/- 2.43). Three of these pancreatic lesions were difficult to determine by routine transaxial images, and detection was obvious only by thin-slice images or multiplanar reconstruction images. Contrast-enhanced CT showed gradual fill-in from the peripheral portion to the center. In addition, 10 of 11 cases did not show main pancreatic duct dilatation even if the tumor size was large. Metastases to the pancreas in lung cancer patients are not so rare and radiologists first have an important role to detect the pancreatic mass and then suggest to metastasis as the likely diagnosis. For this purpose, FDG-PET/CT has an advantage in depicting unsuspected pancreatic metastasis from lung cancer, particularly that which is not detected by CT alone.

Utility of 18F-fluorodeoxyglucose positron emission tomography in the preoperative staging of squamous cell carcinoma of the oropharynx

Background 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been reported to be superior to computed tomography (CT)/magnetic resonance imaging (MRI) in the evaluation of head and neck cancers, but little is known about its usefulness in oropharyngeal squamous cell carcinoma (SCC). We therefore compared FDG PET and CT/MRI in the preoperative staging of previously untreated oropharyngeal SCC. Methods Thirty-two consecutive patients with oropharyngeal SCC underwent FDG PET and CT/MRI before surgery. Each method was interpreted separately to assess primary tumor and cervical node status. Their sensitivity and specificity were compared relative to histopathologic analysis. Results Histopathology revealed metastases in 29 of 39 dissected neck sides and in 47 of 163 dissected cervical levels. FDG PET had higher sensitivities than CT/MRI for primary tumor detection (25/32 vs. 30/32, P = 0.063) and for identification of cervical metastases on neck side (22/29 vs. 28/29, P < 0.05) and level-by-level (37/47 vs. 45/47, P < 0.05) bases. In contrast, the specificity of the two methods did not differ significantly ( P > 0.5). FDG PET correctly interpreted the false-negative results of CT/MRI in 6 of 7 primary tumors and 8 of 10 cervical levels. Conclusions The improved preoperative staging of FDG PET may help in planning treatment, but its accuracy is insufficient to replace pathologic staging based on neck dissection.

Utility of 2-[ 18F] fluoro-2-deoxy- d-glucose positron emission tomography and positron emission tomography/computed tomography imaging in the preoperative staging of head and neck squamous cell carcinoma

The combination of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) has been reported to be more accurate than CT or PET alone in a preoperative setting. We compared the diagnostic utility of preoperative PET/CT, PET and CT/MRI in 167 patients with newly diagnosed head and neck squamous cell carcinoma (HNSCC), of whom 104 underwent FDG PET and 63 underwent combined PET/CT with all receiving CT/MRI. These preoperative PET, PET/CT, and CT/MRI results were reviewed and their accuracies were compared in patients in whom diagnosis was confirmed histopathologically. Age, sex, primary sites and stage, and nodal involvement were comparable between two groups. The accuracy of PET and PET/CT for detecting primary tumors and cervical metastases was comparable, but significantly higher than that of CT/MRI (98%-97% vs. 86-88% for primary; 92%-93% vs. 85%-86% for neck on a level-by-level basis; P<.05). PET and PET/CT gave false negative results: in 2 (2%) and 2 (3%) patients for primary tumors; in 6 (6%) and 3 (5%) patients for neck metastases, respectively. PET and PET/CT also gave false-positive results for cervical metastases in 5 (5%) and 4 (6%) patients, respectively. Compared with PET alone, preoperative FDG PET/CT may not yield significantly improved diagnostic accuracy in patients with HNSCC. Moreover, despite their high accuracy, PET and PET/CT may not abrogate the need for conventional imaging and pathologic staging based on primary resection and neck dissection.

Standardized Uptake Values of Normal Breast Tissue with 2-Deoxy-2-[F-18]Fluoro-d-glucose Positron Emission Tomography: Variations with Age, Breast Density, and Menopausal Status

This study was conducted to assess the effect of breast density, age, and menopausal status on the 2-deoxy-2-[F-18]fluoro-D: -glucose (FDG) uptake in normal breast tissue by quantitative standardized uptake values (SUV). A total of 96 patients (premenopausal 54; postmenopausal 42) with histologically proven unilateral breast cancer who underwent FDG-positron emission tomography (PET) scans for staging were included in this study. The median age was 52+/-11 years (range 32-79 years). Fifty-nine patients had grade III or IV mammographic density (dense breast), whereas 37 patients had grade I or II breast density (nondense) according to the ACR Lexicon criteria. In the present study, we analyzed maximum and average SUVs for contralateral normal breast. Maximum and average SUVs for normal dense breasts were 1.02+/-0.30 and 0.84+/-0.27, respectively. Similar values for the nondense breasts were 0.66+/-0.24 and 0.53+/-0.23, respectively. Both maximum and average SUVs of dense breasts were significantly higher than those of nondense breasts (p<0.001). There was no significant difference in SUVs of nipple in patients with dense and nondense breasts. There was no significant effect of age and menopausal status on SUVs of normal breast. However, there were trends of negative relationship, i.e., decreasing SUVs with increasing age. There was a significant difference in SUVs between the dense and nondense normal breast. However, the maximum SUVs in the dense breasts were well below the threshold of 2.5, a widely used cutoff value for malignancy. Menopausal status and age do not significantly affect the uptake of FDG.

Repetitive 18F‐fluorodeoxyglucose positron emission tomography in giant cell arteritis: A prospective study of 35 patients

To study fluorodeoxyglucose (FDG) uptake in the different vascular beds and in the large joints of patients with giant cell arteritis (GCA) at diagnosis, during steroid treatment, and at relapse. All consecutive patients admitted to our department with a diagnosis of GCA underwent FDG-positron emission tomography (PET) scan before treatment with methylprednisolone was started. PET scans were repeated at 3 and 6 months, if the initial PET scans showed vascular FDG uptake. PET scans were scored at 7 different vascular areas and a total vascular score (TVS) was calculated, ranging from 0 to 21. A total of 35 patients entered the study. At diagnosis, vascular FDG uptake was noted in 29 patients (83%), especially in the subclavian arteries (74%), but also in the aorta (>50%) and up to the femoral arteries (37%). TVS decreased from a mean +/- SD score of 7.9 +/- 5.5 at baseline to 2.4 +/- 3.5 on repeat PET scan at 3 months (P < 0.0005), but did not further decrease at 6 months. The patients who relapsed had similar earlier decreases of TVS compared with those who did not relapse. FDG uptake in the shoulders at diagnosis correlated significantly with the presence of polymyalgia rheumatica (P = 0.005). FDG uptake in the large vessels is a sensitive marker for GCA, which can involve the larger thoracic, abdominal, and peripheral arteries. Polymyalgia rheumatica symptoms in patients with GCA correlate with (peri)synovitis of the shoulders. Relapses of GCA cannot be predicted by results of former PET scintigraphies.

Malignant Lesions Can Mimic Gastric Uptake on FDG PET

Gastric FDG uptake is a common observation on positron emission tomography (PET), which is most frequently caused by a nonmalignant etiology. However, a malignant lesion in the region of the stomach must not be overlooked. A 48-year-old woman with a history of melanoma in the esophagus and status postesophagectomy underwent FDG PET to evaluate for tumor recurrence. The images demonstrated hypermetabolism in the region of the location of the stomach. However, considering that the patient had a history of a stomach pullthrough procedure, we felt that this activity was nongastric and represented tumor recurrence, which was subsequently confirmed by computed tomography scan and histopathologic examination.

OP8. REPETITIVE 18-FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY IN GIANT CELL ARTERITIS: A PROSPECTIVE STUDY IN 35 PATIENTS

Objective: To study fluorodeoxyglucose (FDG)-deposition in the different vascular beds and in the large joints of patients with giant-cell arteritis (GCA), at diagnosis and during steroid treatment. Methods: All consecutive patients admitted to our department with a diagnosis of GCA underwent FDG-positron emission tomography (PET) scan before treatment with methylprednisolone was started. PET-scans were repeated at 3 and 6 months, if the initial PET scans showed vascular FDG-uptake. PET-scans were scored at 7 different vascular areas and a total vascular score (TVS) was calculated, ranging from 0 to 21. Results: 35 patients entered the study. At diagnosis, vascular FDG-uptake was noted in 29 patients (83%). There was no correlation between FDG findings and laboratory parameters or patients complaints, except for jaw claudication. FDG-uptake in the shoulders correlated significantly with the presence of polymyalgia rheumatica (p = 0.005). TVS decreased from a mean score of 7.9±5.5 at baseline to 2.4±3.5 on repeat PET scan at 3 months (p<0.0005) but did no further decrease at 6 months. The patients who had a relapse had similar decreases of TVS compared to those who did not relapse. Conclusions: FDG-uptake in the large vessels is a sensitive marker for GCA, which can involve the larger thoracic, abdominal and peripheral arteries. Polymyalgia rheumatica complaints in GCA patients correlate with (peri)synovitis of the shoulders and not with inflammation of the subclavian or axillary arteries. Relapses of GCA cannot be predicted by results of former PET scintigraphies.

DNA ploidy, S-phase fraction and associations with 2-18F-fluoro-deoxy-2-D-glucose positron emission tomography findings before and during therapy of head and neck squamous cell carcinoma

ObjectivesThe main purpose of this study was to investigate the feasibility of fine needle aspiration (FNA) of neck node metastases in head and neck squamous cell carcinoma (HNSCC) for evaluating changes in DNA ploidy and S-phase fraction (SPF) during cytotoxic treatment. The results of flow cytometric (FCM) and image cytometric (ICM) analyses of ploidy were compared. Secondly, the association of SPF and ploidy with the metabolic rate (MR) of 2-18F-fluoro-deoxy-2-D-glucose (FDG) in positron emission tomography (PET) was studied.Material and MethodsBetween 1993 and 1999, 47 patients with locally advanced, non-resectable HNSCC underwent FDG PET prior to (PET1) and early during (PET2) cytotoxic radical treatment. The MR of FDG was calculated separately in primary tumours and lymph node metastases. Immediately after both PET scans, FNA of node metastases was done in 29 patients at PET1 and in 27 at PET2. DNA ploidy was evaluated using FCM and manually using ICM. The SPF was evaluated using FCM only.ResultsAt PET1 it was possible to evaluate the SPF using FCM in only 13/29 aspirations due to a poor cell yield or large amounts of debris. Ploidy was obtained in 23/29 aspirates using FCM and in 27/29 using ICM. A discordance in ploidy findings was apparent, with more non-diploid clones being detected by ICM than FCM. Eradication of non-diploid clones during therapy was observed in six cases using FCM, of which only one was confirmed by ICM. Neither SPF nor ploidy status showed any strong correlation with the MR of FDG.ConclusionFNA of HNSCC metastases demands a high and qualitatively good cell yield for FCM examinations. ICM is laborious but feasible and offers more accurate detection of non-diploid cell clones. Ploidy and SPF were not strongly associated with FDG metabolism.

The Role of [18F]Fluorodeoxyglucose Positron Emission Tomography Imaging in the Evaluation of Hepatocellular Carcinoma

It has been well established that hepatocellular carcinomas (HCCs) accumulate [18F]fluorodeoxy-glucose (FDG) to varying degrees; this is thought to be due to differing amounts of FDG-6-phosphatase activity. The purpose of this study was to evaluate the impact of FDG imaging on the management of patients diagnosed with hepatocellular carcinoma. We conducted a retrospective review of the clinical data of 91 consecutive patients diagnosed with HCC who underwent FDG-positron emission tomography (PET) imaging between August 1993 and March 2001. The patients were divided into two groups. In Group one 67 of 91 (74%) patients were evaluated for proven but untreated hepatic lesions using PET. In Group two the remaining 24 patients (26%) were referred for evaluation of HCC recurrence but did not have prior PET. The FDG images were acquired with two dedicated PET tomographs [Siemens ECAT 933, CTI (Knoxville, TN) and GE Advance, General Electric Medical Systems (Milwaukee, WI)] one hour after the intravenous administration of 10 mCi of FDG. Tumor biopsy or resection specimens were available for review from 34 patients and were evaluated for histologic grade, presence of cirrhosis, tumor necrosis, and intratumoral fibrosis. In group one 43 of 67 (64%) of the HCCs accumulated FDG. Sixteen of the 43 patients in whom FDG was accumulated had multiple subsequent FDG-PET scans either for monitoring therapy or for detection of recurrence. FDG-PET imaging had an impact on the management of 20 of these patients: by guiding the biopsy at the metabolically active site of a large necrotic tumor (one), by identifying distant metastases (five), by monitoring the response to treatment with hepatic chemoembolization and guiding additional regional therapy (12), and by detecting recurrence (two). In group two recurrence and/or metastases were demonstrated with FDG-PET imaging in six of 24 (25%) patients, three of whom had multiple subsequent FDG-PET scans to monitor their treatment. Higher histopathologic grade and intratumoral fibrosis but not necrosis or cirrhosis correlated with PET positivity. In this study only 64 per cent of HCCs accumulated FDG. Despite this limitation FDG-PET imaging remains a useful tool in the diagnosis and treatment of HCC. FDG-PET imaging had a clinically significant impact in 26 of 91 (28%) patients with HCC. This includes detection of unsuspected metastatic disease in high-risk patients—including liver transplant candidates—and monitoring response to hepatic-directed therapy. FDG-PET should be considered as part of the workup and management of selected patients with HCC.

FDG PET of Pleural Effusions in Patients with Non—Small Cell Lung Cancer

We determined the ability of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to differentiate benign and malignant pleural effusions in patients with non-small cell lung cancer. Over a 6-year period, we reviewed all patients with primary non-small cell lung cancer and a pleural effusion on staging CT who underwent FDG PET. We examined 25 patients (18 men and seven women; age range, 37-86 years; mean age, 65 years). FDG PET revealed positive findings if pleural activity was greater than background mediastinal activity; FDG PET revealed negative findings if pleural activity was the same as or less than background mediastinal activity. Results of FDG PET were correlated with pathologic diagnosis determined with thoracentesis or pleural biopsy. All patients had effusions on the same side as the primary tumor. Twenty-two patients had a malignant pleural effusion confirmed with thoracentesis (n = 19) or biopsy (n = 3). FDG PET revealed positive findings in 21 patients and negative findings in one. Three patients had no evidence of malignancy in the pleural space determined with cytologic findings (n = 2) or biopsy results (n = 1). FDG PET uptake revealed positive findings in one of these patients and negative findings in two. Therefore, of 22 patients with positive findings on FDG PET, 21 had pleural metastases, and of three patients with negative findings on FDG PET, one had metastases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG PET for detecting pleural metastases were 95%, 67%, 95%, 67%, and 92%, respectively. This study suggests that FDG PET may be useful in improving staging evaluation in patients with non-small cell lung cancer and a pleural effusion. Increased pleural FDG uptake usually indicates pleural metastases; however, because the number of benign effusions studied was small, the relevance of negative findings on FDG PET in this setting is uncertain.

Prognostic value of thoracic FDG PET imaging after treatment for non-small cell lung cancer.

We determined the prognostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for patients with treated lung cancer. We examined patients who underwent FDG PET after first-line treatment for non-small cell lung cancer. FDG PET results were correlated with survival rates to determine whether FDG PET findings were predictive of outcomes. After initial therapy, 113 patients with non-small cell lung cancer underwent FDG PET. One hundred patients had positive FDG PET results and a median survival of 12 months (95% confidence interval, 9.2-15.4). Thirteen patients had negative FDG PET results, and 11 (85%) of these patients are still living at a median follow-up of 34 months. The difference in survival for patients with positive and negative FDG PET results was statistically significant (p = 0.002). FDG PET has prognostic value and strongly correlates with survival rates of patients with treated lung cancer. Patients with positive FDG PET results have a significantly worse prognosis than patients with negative results. Additionally, FDG PET may be helpful in guiding therapeutic treatments.