Oral nutritional supplements (ONSs) for cirrhotic patients undergoing liver resection assessed by ultrasound measurement of rectus femoris and anterior tibialis muscles thickness. Randomized clinical trial.

PURPOSE: We evaluated the effects of postoperative administration of (ONSs) on the liver function and the outcome of cirrhotic patients using ultrasound (US) assessment of rectus femoris (RF) and anterior tibialis (AT) muscles. PATIENTS AND METHODS: Forty-three malnourished adult hepatic patients who underwent major liver resections were recruited in this study. In the conventional diet (CD) group, the patients took water at postoperative day (POD) 0 and routine soft diet starting from POD1. In the ONS group, a commercially elemental diet was started from POD1 for 7 days postoperatively, with a target endpoint of 35-40 kcal/kg and 1.2-1.5 g/kg of protein per day. US assessment of the RF and AT muscles was done preoperatively and at POD3 and 7, including anterior-posterior (AP) diameter, lateral-lateral (LL) diameter, and cross-sectional area (CSA). Muscles' echogenicity was defined by the Heckmatt scale. The outcome of the patients was also recorded. RESULTS: Consumption of ONS preserved the measured RF and AT characteristics (AP and LL diameters and CSA) in the ONS group at POD3 and 7 compared to the CD group. Heckmatt scale was significantly increased at POD3 and 7 in the CD group compared to the ONS group. Both total protein and albumin levels at POD3 and 7 were significantly lower in the CD group compared to the ONS group [P = (0.02, 0.03) and (0.05, 0.04), respectively]. Serum phosphate was significantly lower at POD7 in the ONS group than the CD group (p = 0.04). There were significant decreases in the ICU stay and time of passing flatus (h) in the ONS group comparing with the CD group (P = 0.045 and P = 0.00, respectively). CONCLUSIONS: ONS maintains muscle mass and echogenicity of RF and AT along with better liver function and intestinal function recovery.

Advanced intra-tumoural structural characterisation of hepatocellular carcinoma utilising FDG-PET/CT: a comparative study of radiomics and metabolic features in 3D and 2D.

PURPOSE: The aim of our work is to evaluate the correlation of two-dimensional (2D) and three-dimensional (3D) radiomics and metabolic features of hepatocellular carcinoma (HCC) with tumour diameter, staging, and metabolic tumour volume (MTV). MATERIAL AND METHODS: Thirty-three patients with HCC were studied using 18F-fluorodeoxyglucose positron-emission tomography with computed tomography (18F [FDG] PET/CT). The tumours were segmented from the PET images after CT correction. Metabolic parameters and 35 radiomics features were compared using 2D and 3D modes. The metabolic parameters and tumour morphology were compared using 2 different types of software. Tumour heterogeneity was studied in both metabolic parameters and radiomics features. Finally, the correlation between the metabolic and radiomics features in 3D mode, as well as tumour morphology and staging according to the American Joint Committee on Cancer (AJCC) staging were studied. RESULTS: Most of the metabolic parameters and radiomics features are statically stable through the 2D and 3D modes. Most of the 3D mode features show a correlation with metabolic parameters; the total lesion glycolysis (TLG) shows the highest correlation, with a Spearman correlation coefficient (rs) of 0.9776. Also, the grey level run length matrix/run length non-uniformity (GLRLM_RLNU) from radiomics features exhibits a correlation with a Spearman correlation coefficient of 0.9733. Maximum tumour diameter is correlated with TLG and GLRLM_RLNU, with rs equal to 0.7461 and 0.7143, respectively. Regarding AJCC staging, some features show a medium but prognostic correlation. In the case of 2D-mode features, all metabolic and radiomics features show no significant correlation with MTV, AJCC staging, and tumour maximum diameter. CONCLUSIONS: Most of the normal metabolic parameters and radiomics features are statistically stable through the 3D and 2D modes. 3D radiomics features are significantly correlated with tumour volume, maximum diameter, and staging. Conversely, 2D features have negligible correlation with the same parameters. Therefore, 3D mode features are preferable and can accurately evaluate tumour heterogeneity.

Portal vein thrombosis in hepatitis C virus-related cirrhotic patients: Prevalence and clinical characteristics in an Egyptian cohort.

Portal vein thrombosis is a catastrophe not uncommonly complicating hepatitis C virus-related liver cirrhosis. To estimate its prevalence and clinical characteristics, we investigated 1000 cirrhotic patients by abdominal ultrasound or Doppler study at least. Portal vein thrombosis was found in 21.6%, of whom 157 (72.7%) had malignancy. Complete portal vein thrombosis was found in 70.4%. Half of all these patients had at least one episode of portal hypertensive bleeding, a third had abdominal pain and a quarter presented with jaundice. Portal bilopathy was diagnosed in two cases (0.9%). There was significant association between severity of liver disease, ascites, male gender and site of segmental focal lesion and portal vein thrombosis.

Comparison of atherosclerotic inflammation and calcification in subjects with end stage renal disease (ESRD) on hemodialysis to normal controls utilizing 18F-FDG PET/CT.

OBJECTIVE: Subjects with end stage renal disease (ESRD) are exposed to increased morbidity and mortality due to cardiovascular events. The primary underlying mechanism has been suggested as accelerated atherosclerosis in these patients. Our aim was to compare the atherosclerotic inflammation and calcification in subjects with ESRD on hemodialysis to that in normal controls utilizing fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT). SUBJECTS AND METHODS: Forthy two subjects who underwent 18F-FDG PET/CT imaging were retrospectively studied. Twenty one were subjects with ESRD on hemodialysis (67±11 years old; 14 male, 7 female) and 21 were age- and gender-matched controls. Average standardized uptake value maximum (SUVmax) and SUVmean for 4 segments of the aorta (ascending, arch, descending, abdominal) and for the common iliac arteries and common femoral arteries were measured. Standardized uptake value maximum and SUVmean for right atrial blood pool were also measured as the background. Average SUVmax, average SUVmean, average SUVmax/background ratio, and average SUVmean/background ratio were compared between subject groups for all segments. Presence or absence of macroscopic calcification on CT images for each arterial segment based on visual qualitative assessment was also noted and compared. For statistical analysis, two-sided t-test was used for continuous variables, and chi-square test was used for categorical variables. We considered a P value of <0.05 as statistically significant. RESULTS: Average SUVmax and SUVmean were statistically significantly greater in subjects with ESRD than in controls in all arterial segments. Average SUVmax/background ratios were statistically significantly greater in subjects with ESRD compared to normal controls in all arterial segments except for the left femoral artery. Average SUVmean/background ratios were statistically significantly greater in subjects with ESRD compared to normal controls in all arterial segments except for the right and left femoral arteries. Presence of calcification on CT was more frequently encountered in all arterial segments in subjects with ESRD, and was statistically significantly greater for the aortic arch, descending aorta, and right and left femoral arteries. CONCLUSION: SUV measurements representing the atherosclerotic inflammatory changes and macroscopic atherosclerotic calcifications appear to be accelerated in subjects with ESRD on hemodialysis compared to normal controls. Fluorine-18 FDG PET/CT is a valuable diagnostic tool for verifying and quantifying accelerated atherosclerosis secondary to ESRD.

Is 18F-FDG PET/CT a valuable diagnostic tool for verifying accelerated atherosclerosis secondary to diabetes mellitus on insulin in the aortic segments and large arteries?

OBJECTIVE: Fluorine-18 fluorodeoxylglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has a well-established role for detection and quantification of atherosclerotic inflammatory disease using standardized uptake value (SUV) measurements. Our aim was to compare the inflammatory and macroscopic calcification processes of atherosclerosis in the aortic segments and large arteries of subjects with insulin dependent diametes mellitus (IDDM) compared to those of age-matched controls via 18F-FDG PET/CT. PATIENTS AND METHODS: A hundred and ten subjects who underwent 18F-FDG PET/CT imaging for oncological diseases were retrospectively studied. Fifty five were diabetics on insulin and 55 were age-matched controls. Average SUVmax and SUVmean for four segments of aorta and for common iliac arteries and femoral arteries were measured and compared between subject groups. Presence or absence of macroscopic calcification on CT images for each arterial segment was also noted and compared between these groups. RESULTS: Average SUVmax and SUVmean were statistically significantly greater in subjects with IDDM compared to controls in all arterial segments (P≤0.001). Presence of calcification on CT was more frequently encountered in 6 of the 8 segments in subjects with IDDM, and there was statistically significantly difference for the descending aorta and abdominal aorta. CONCLUSION: Our results show that inflammatory component of atherosclerosis was more severe in all aortic segments in subjects with IDDM compared to those of controls. Presence of macroscopic calcification also detected to be more frequently encountered in the descending thoracic and abdominal aorta in subjects with IDDM. Fluorine-18-FDG PET/CT is a valuable diagnostic tool for detecting and semi-quantifying accelerated atherosclerotic inflammatory and calcific changes secondary to diabetes mellitus treated with insulin in the aortic segments and large arteries.

Segmental peri-coronary epicardial adipose tissue volume and coronary plaque characteristics.

AIMS: Epicardial adipose tissue (EAT) has been proposed to modulate underlying coronary plaque features. The study aimed to determine the relation between segmental EAT (sEAT) volume, assessed by cardiac magnetic resonance (CMR), and underlying coronary plaque characteristics, as estimated by multidetector computed tomography (CT) (MDCT). METHODS AND RESULTS: The study included 32 male patients with stable angina pectoris and 11 age-matched healthy controls. For each CAD patient, sEAT volume around 8 coronary segments (3 in left anterior descending artery, 3 in right coronary artery, and 2 in left circumflex artery) was quantified by CMR. By MDCT, plaques in each coronary segment were characterized in terms of plaque volume, type, CT attenuation, and severity of luminal stenosis. Serum levels of adipokines were measured. Total EAT volume was significantly higher in CAD patients than in control group. Serum resistin showed significant correlation with EAT volume (r = 0.69, P < 0.001). Analysis of 256 coronary segments showed larger sEAT volume with increasing luminal stenosis of the corresponding segment (mild: 8.2 cm(3); moderate: 11 cm(3); severe: 11.8 cm(3), P < 0.001). sEAT volume was larger in segments with mixed than those with calcified or non-calcified plaques (12.1 vs. 10.2 vs. 9.5 cm(3), respectively, P = 0.015). sEAT volume was larger in segments with low CT attenuation non-calcified plaques compared with non-calcified plaques with CT attenuation >30 HU (10.5 vs. 8.2 mm(3), P < 0.001). CONCLUSION: Peri-coronary epicardial adipose tissue volume is significantly associated with the extent and severity of coronary atherosclerosis and may be a determinant of plaque vulnerability.

Partial volume correction and image segmentation for accurate measurement of standardized uptake value of grey matter in the brain.

OBJECTIVES: Our aim was to explore a novel quantitative method [based upon an MRI-based image segmentation that allows actual calculation of grey matter, white matter and cerebrospinal fluid (CSF) volumes] for overcoming the difficulties associated with conventional techniques for measuring actual metabolic activity of the grey matter. METHODS: We included four patients with normal brain MRI and fluorine-18 fluorodeoxyglucose (F-FDG)-PET scans (two women and two men; mean age 46±14 years) in this analysis. The time interval between the two scans was 0-180 days. We calculated the volumes of grey matter, white matter and CSF by using a novel segmentation technique applied to the MRI images. We measured the mean standardized uptake value (SUV) representing the whole metabolic activity of the brain from the F-FDG-PET images. We also calculated the white matter SUV from the upper transaxial slices (centrum semiovale) of the F-FDG-PET images. The whole brain volume was calculated by summing up the volumes of the white matter, grey matter and CSF. The global cerebral metabolic activity was calculated by multiplying the mean SUV with total brain volume. The whole brain white matter metabolic activity was calculated by multiplying the mean SUV for the white matter by the white matter volume. The global cerebral metabolic activity only reflects those of the grey matter and the white matter, whereas that of the CSF is zero. We subtracted the global white matter metabolic activity from that of the whole brain, resulting in the global grey matter metabolism alone. We then divided the grey matter global metabolic activity by grey matter volume to accurately calculate the SUV for the grey matter alone. RESULTS: The brain volumes ranged between 1546 and 1924 ml. The mean SUV for total brain was 4.8-7. Total metabolic burden of the brain ranged from 5565 to 9617. The mean SUV for white matter was 2.8-4.1. On the basis of these measurements we generated the grey matter SUV, which ranged from 8.1 to 11.3. CONCLUSION: The accurate metabolic activity of the grey matter can be calculated using the novel segmentation technique that we applied to MRI. By combining these quantitative data with those generated from F-FDG-PET images we were able to calculate the accurate metabolic activity of the grey matter. These types of measurements will be of great value in accurate analysis of the data from patients with neuropsychiatric disorders.

The added value of PET/Ce-CT/DW-MRI fusion in assessment of hepatic focal lesions: PET/Ce-CT/DW-MRI fusion in hepatic focal lesion.

INTRODUCTION: The liver hosts a variety of benign and malignant tumors. Accurate diagnosis can be challenging in certain cases, especially in patients with a history of malignancy or in those with underlying liver pathology, such as cirrhosis. OBJECTIVES: To evaluate the added clinical value of multi-modality liver imaging utilizing PET/Ce-CT/DW-MRI for characterization of hepatic focal lesions (HFL) and compare it with each diagnostic modality when interpreted alone. METHODS: The study included 35 patients with HFL. They were 7 females & 28 males; their age ranged from 41 to 78years, all patients underwent PET/Ce-CT and DW-MRI scans. Ce-CT, PET and DW-MR images were reviewed independently, and then combined PET/Ce-CT, PET/DW-MRI and PET/Ce-CT/DW-MRI scans were analyzed. The results were correlated with histopathology or clinical/imaging follow-up. RESULTS: The 35 patients had 98 focal lesions. Fifty-three lesions were finally diagnosed as primary hepatocellular carcinoma, 18 lesions were metastases, 7 lesions were lymphoma and 20 lesions were benign. On a patient based analysis; the sensitivity, specificity, PPV, NPV and accuracy were 100%, 67%, 94%, 100% and 94% for PET/Ce-CT compared to 97%, 83%, 97%, 83% and 94 % for DW-MRI, respectively. Combined PET/Ce-CT/DW-MR scans raise those parameters up to 100%. On a lesion based analysis; the sensitivity, specificity, PPV, NPV and accuracy were 94%, 75%, 94%, 75%, 90% for PET/Ce-CT compared to 94%, 95%, 99%, 97% and 94 % for DW-MRI, respectively. All these parameters were 100 % with PET/Ce-CT/DW-MRI. CONCLUSIONS: The addition of DW-MRI to PET/Ce-CT is valuable in the characterization of hepatic focal lesions.

Atherosclerotic inflammatory activity in the aorta and its correlation with aging and gender as assessed by 18F-FDG-PET.

Recent literature demonstrates the potential of fluorine-18 fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) to detect, localize, and quantify the degree of inflammatory changes in the arterial wall due to early atherosclerosis. Our aim was to assess the correlation between the age and 18F-FDG uptake of aortic segments and determine its correlation with respect to in both age and genders. Fluorine-18-FDG uptake in aortic segments in 143 subjects (58 men, 85 women; ages 5-82 years) was evaluated in this study. Subjects were initially grouped according to the gender, and then by age (below or above 50) with at least 26 subjects per group. Mean standardized uptake value (SUV) of ascending aorta, arch, descending thoracic aorta, and abdominal aortic segments were calculated in each subject. Correlative analyses between age and mean SUV of aortic segments in all subjects were undertaken. Mean SUV between genders for all groups were also compared. There was a positive correlation between age and mean SUV of all aortic segments. The correlation values in all aortic segments were higher in subjects below 50 years old compared to those above 50 years in the entire group of patients as well as when they were subdivided and analyzed according to both genders (P<0.001). Descending thoracic and ascending aortic segments in men below 50 years of age had the highest correlation of 18F-FDG uptake and age (0.85 and 0.80, respectively) whereas abdominal aortic segments in men the above 50 years age group had the lowest correlation value (0.20). Comparison between mean SUV in four visible arterial segments between the two genders did not reveal any statistically significant difference. In conclusion, 18F-FDG uptake in aortic segments increases with age irrespective of genders. The increase with age is more significant in younger subjects compared to older subjects for both men and women. This finding may indicate a deceleration in the inflammatory component of atherosclerosis with aging in older subjects.

The effects of aging on testicular volume and glucose metabolism: an investigation with ultrasonography and FDG-PET.

OBJECTIVES: To investigate the effects of senescence on testicular volume and metabolism by quantitative analysis of volumetric and functional data provided by genital ultrasonography (US) and 2-deoxy-2-[(18)F]fluoro-D-glucose(-)positron emission tomography (FDG-PET), respectively. METHODS: Three hundred twenty (PET 173, US 147) male subjects (average age, 47.9 ± 24.1 years; range, 11-90 years) who previously underwent US or FDG-PET imaging were included in this retrospective study. Testicular volumes and FDG maximum standardized uptake values (SUV(max)) were correlated with age using polynomial regression and Pearson linear regression analysis. RESULTS: With cross-sectional analysis, the best-fit curves demonstrated statistically significant overall correlations between changes in both the volume and metabolism (SUV(max)) of the testicle and increasing age (volume: R(2) = 0.42, p = 0.0002; SUV(max): R(2) = 0.26, p < 0.0001). Testicular volume rapidly increases during puberty and peaks at age 30 years. Subsequently, the volume of the testes stabilizes in a plateau-like manner until age 60 years. After age 60 years, this study shows that testicular volume decreases significantly. Testicular glucose metabolism increases until age 40 years, after which it declines gradually over time at a constant rate. CONCLUSION: Testicular volume and metabolism appear to be significantly affected by advancing age at different rates during the different stages of lifespan. The rapid increase in testicular volume and metabolism parallel the onset and progression of puberty and positively correlate with increasing age up to ages 30-40 years. Between ages 40 and 60 years, testicular volume and metabolism remain relatively constant with only a minimal decline. After age of 60 years, the testicular volume significantly declines, while testicular metabolism progressively declines until age 90 years.

Multimodality Imaging Assessment of Pulmonary Nodules.

A common clinical dilemma is the evaluation of pulmonary nodules detected on imaging. Differentiation between malignant and benign pulmonary nodules is a complex problem despite major advances in medical imaging. Accurate diagnosis helps to eliminate unnecessary surgical procedures in patients with benign diseases. It is important for the diagnostician to be aware of the role of multimodality imaging for characterization of pulmonary nodules.

Increased 18F-FDG uptake within the reticuloendothelial system in patients with active lung cancer on PET imaging may indicate activation of the systemic immune response.

The reticuloendothelial system (RES) cells are in the defense against certain pathogens, and in the removal of dying cells, cell debris, microorganisms, and malignant cells. Liver, spleen, and bone marrow represent the major organs with high RES activity. We hypothesized that in subjects with active lung cancer, the metabolic activity of these organs would be greater than that of the subjects with no active tumor. We have studied two groups of subjects who had undergone (18)F-FDG-PET imaging for clinical purposes. The first group consisted of 39 subjects (20 women, 19 men, mean age 64.8+/-10.2 years) with benign lung nodules as demonstrated by (18)F-FDG-PET imaging. The second group consisted of 30 subjects (18 women, 12 men; mean age 65.1+/-11 years) who were known to have active lung cancer with or without distant metastases as seen on (18)F-FDG-PET imaging. The subjects in the second group did not have any evidence of liver, spleen, bone marrow, or heart involvement on (18)F-FDG-PET images. We measured the mean SUV of the liver, spleen, bone marrow, heart, and of the contralateral unaffected lung, and compared the average SUV for these organs between the two groups. We found that the mean SUV of the liver, bone marrow, and spleen were significantly greater in subjects with evidence of active primary or metastatic lung cancer compared with those of subjects who had benign lung nodules and no evidence of active malignant disease. There was a statistically significant difference between mean SUV for organs noted above between the two groups (P<0.05). In contrast, mean SUV for the heart and contralateral normal lung did not show any significant difference between the two groups. In conclusion, the mean SUV for the major organs of RES, liver, spleen, and bone marrow were higher in subjects with active lung cancer with or without metastases than in those without active malignancy. We believe these differences in SUV may indicate a differential activation of the systemic immune response, related to the presence or absence of active lung cancer, which can be detected and quantified non-invasively through (18)F-FDG-PET imaging.

Prognostic implication of dual-phase PET in adenocarcinoma of the lung.

UNLABELLED: The purpose of this study was to determine whether dual-phase (18)F-FDG PET could be a prognostic factor for adenocarcinoma of the lung. METHODS: One hundred patients with histologically proven adenocarcinoma of the lung were included in this retrospective analysis. All patients underwent dual-phase pretherapy (18)F-FDG PET for which, after the intravenous administration of (18)F-FDG, both early (approximately 60 min) and delayed (approximately 90 min) PET were acquired. The percentage change in the maximal standardized uptake values (SUVmax) of the cancer between the early and the delayed images was calculated. Overall survival of the SUVmax change over time together with the known prognostic factors were calculated by the Kaplan-Meier method and evaluated with the log-rank test. The prognostic significance was assessed by univariate and multivariate analyses. RESULTS: Statistical analysis showed that SUVmax change over time between the early and the delayed PET was a strong independent predictor of outcome for lung adenocarcinoma. A cutoff of 25% change for SUVmax over time showed the best discriminative value. Patients with more than 25% increase in SUVmax had a median survival of 15 mo, compared with 39 mo for those with less than 25% increase in SUVmax. CONCLUSION: Dual-phase (18)F-FDG PET reflects the dynamics of glucose metabolism. Our findings suggest that the percentage SUVmax change over time is a strong prognostic factor in patients with lung adenocarcinoma and can be complementary to the other well-known factors.

Quantitative assessment of the hepatic metabolic volume product in patients with diffuse hepatic steatosis and normal controls through use of FDG-PET and MR imaging: a novel concept.

AIMS AND OBJECTIVES: The aim of this study was to compare hepatic standardized uptake values (SUVs) and hepatic metabolic volumetric products (HMVP) between patients of diffuse hepatic steatosis and control subjects with normal livers. MATERIALS AND METHODS: Twenty-seven subjects were included in the study (13 men and 14 women; age range, 34-72 years). All had 18F-2-fluoro-2-D-deoxyglucose-positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) scans with an interscan interval of 0-5 months. Twelve of 27 subjects had diffuse hepatic steatosis on MRI. The remaining 15 were selected as age-matched controls based on normal liver parenchyma on MRI. Mean and maximum hepatic SUVs were calculated for both patient groups on FDG-PET images. Hepatic volumes were measured from MRI. HMVP in each subject was subsequently calculated by multiplication of hepatic volume by mean hepatic SUV. HMVPs as well as mean and maximum hepatic SUVs were compared between the two study groups. RESULTS: HMVPs, mean hepatic SUVs, and maximum hepatic SUVs were greater (statistically significant, p < 0.05) in subjects with diffuse hepatic steatosis compared to those in the control group. CONCLUSION: The increase in HMVP is the result of increased hepatic metabolic activity likely related to the diffuse hepatic steatosis. The active inflammatory process related to the diffuse hepatic steatosis is the probable explanation for the increase in hepatic metabolic activity on FDG-PET study.

Tumor metabolism measured by partial volume corrected standardized uptake value varies considerably in primary and metastatic sites in patients with lung cancer. A new observation.

Fluorine-18 fluorodeoxyglycose -position emission tomography ((18)F-FDG-PET) as an efficient staging tool for lung carcinoma; allows description and characterization of the primary tumor and of local and distant metastases in a single examination. One of the important limiting factors in quantification of metabolic parameters with PET is the partial volume effect. Our aim for this study was to delineate tumor (size) both in the primary and metastatic lesions in patients with lung cancer by using partial volume correction techniques. Thirty two patients with proven lung cancer who had (18)F-FDG-PET and computerized tomography (CT) within the last 80 days were involved in this study. They were 18 women and 14 men, with age range 43-83 years. Maximum standardized uptake values (SUVmax) in primary and metastatic lesions for all patients were measured. The lesions were categorized into 4 different Groups according to their site. Partial volume corrections were applied using the CT sizes of lesions to obtain corrected SUVmax values. Average corrected SUVmax in each lesion site was calculated and compared between the 4 Groups. A total of 81 primary and metastatic lesions were included in this analysis. They were 28 mediastinal-hilar lymph node lesions, 26 lung lesions, 11 solid organ lesions, and 16 bone marrow lesions. The average uncorrected SUVmax for the primary lung lesions, mediastinal-hilar lymph node lesions, solid organ lesions, and the bone marrow lesions before application of partial volume correction formula were 7.2+/-3.2; 7.0+/-2.7; 6.3+/-3.4 and 7.0+/-3.4, respectively. The average corrected SUVmax for the lesions in the above mentioned regions were 11+/-6, 10+/-4, 13+/-7, and 18+/-13, respectively. A statistically significant difference was observed in the average SUVmax values between lung lesions and nodal lesions compared to the bone marrow lesions. In conclusion, our findings indicate that metabolic activities of lung cancer lesions vary depending on the sites of metastatic disease.

A pilot study of changes in (18)F-FDG uptake, calcification and global metabolic activity of the aorta with aging.

Our aim was to quantify changes in the inflammatory and calcific components of atherosclerosis in the aortic wall using fluoro-18-2-fluoro-2-deoxy-D-glucose positron emission tomography (18)F-FDGPET and contrast enhanced computerized tomography (CECT) with increasing age. Twelve subjects, 8 men and 4 women aged from 21-80 years who had both (18)F-FDG-PET and CECT of the chest and abdomen were included in this study. Subjects were grouped into three according to age. (18)F-FDG uptake in four segments of the aorta was measured. Using CECT images, aortic segmental wall volumes were measured. Wall calcification volume in each aortic segment was also measured via adaptation of a coronary artery calcium-scoring program to the aorta. Calcification volumes were then subtracted from aortic wall volumes. Each net segmental aortic wall volume was then multiplied by the accompanying mean SUV of the segment to calculate global metabolic activity (GMA) for each aortic segment. Our results showed that in each aortic wall segment, mean SUV, wall volumes, wall calcification volumes, and GMA statistically significantly increased with age. In conclusion, (18)F-FDG uptake, wall volume, wall calcification volume, and GMA in the aorta increase with aging. The (18)F-FDG uptake represents the early inflammatory component of the atherosclerotic process, whereas calcification generally represents a later and irreversible stage of the disease. Measurement and combination of PET and CECT parameters to calculate GMA may allow for optimal morphologic and functional noninvasive quantitative assessment of global aortic atherosclerotic disease.

Potential of dual time point FDG-PET imaging in differentiating malignant from benign pleural disease.

AIM: The aim of this study was to assess the utility of dual time point 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) imaging in differentiating benign from malignant pleural disease. METHODS: Fifty-five consecutive patients of suspected malignant pleural mesothelioma (MPM) and recurrence of MPM who were referred for the evaluation underwent two sequential 18F-FDG-PET scans (dual time point imaging). The average percent change in the maximum standardized uptake values (Delta%SUVmax) of the lesion/lesions between time point 1 (SUV(max1)) and time point 2 (SUV(max2)) was calculated. All PET results were correlated with the histopathological or cytopathology results. Patients were divided into three principal groups (A = newly diagnosed MPM, B = recurrent MPM, and C = benign pleural disease). The parameters of 18F-FDG uptake (SUV(max) values and its changes over time) were compared among groups. RESULTS: Among the 55 patients who had undergone dual time point 18F-FDG-PET studies, 44 were diagnosed with MPM (28 newly diagnosed and 16 had recurrence). The PET studies demonstrated 229 malignant pleural lesions in these patients. The remaining 11 patients were proven to have benign pleural disease. The mean +/- SD of the SUV(max1), SUV(max2), and the Delta%SUV(max) of the all lesions of each patient in groups A, B, and C were 5.0 +/- 2.2%, 5.8 +/- 2.8%, and 12.8 +/- 8.4%; 4.6 +/- 1.7%, 5.3 +/- 2.0%, 13.8 +/- 9.2%; and 1.6 +/- 0.4%, 1.4 +/- 0.3%, and-9.6 +/- 19.1%, respectively. The mean +/- SD of the SUV(max1), SUV(max2), and Delta%SUV(max) in patients with both newly diagnosed and recurrent MPM were significantly higher than those of benign pleural disease group (p < 0.0001). For each patient, the most intense (hottest) lesion's SUV(max1), SUV(max2), and Delta%SUV(max) were also compared among the aforementioned groups, and these results again confirmed that MPM lesions had significantly higher values than those of benign pleural lesions (p < 0.0001). CONCLUSIONS: There is an increasing uptake of (18)F-FDG over time in pleural malignancies, whereas the uptake in benign pleural disease generally stays stable or decreases over time. Therefore, dual time point imaging appears to be an effective approach in differentiating benign from malignant pleural disease, which increases the sensitivity and is also helpful in guiding the biopsy site for a successful diagnosis.

Usefulness of non attenuation corrected 18F-FDG-PET images for optimal assessment of disease activity in patients with lymphoma.

This study aimed at determining whether non attenuation corrected (NAC) positron emission tomography (PET) images, in addition to the attenuation corrected (AC) PET images, should be included in the interpretation of fluoro-18 fluorodeoxyglucose ((18)F-FDG-PET) images in patients with lymphoma. The study included 58 patients, 35 males 23 females, mean age 55+/-16 years. There were 64 superficial and 170 deep lymph node (LN) lesions. Lesion detection, uptake intensity using a three-point scale (1-mild, 2-moderate, 3- intense) and overall clarity of each lesion were compared on both PET images. Our results showed that the detection rate for superficial LN was 100% for NAC-PET and 98.4% for AC-PET images. The degree of (18)F-FDG uptake (intense, moderate and mild uptake) was 56.3%, 31.3% and 12.5% for NAC-PET images and 23.4%, 34.4% and 40.6% for AC-PET images, respectively. The overall image clarity was significantly in favor of NAC compared to AC-PET images (89% vs 20%, P<0.01). For deep LN, lesions, detection rate was for NAC and AC-PET images 95.3% and 99.4%, respectively. (18)F-FDG uptake intensity (intense, moderate and mild uptake) was 42.4%, 27.1% and 25.9% for NAC and 52.4%, 43% and 4.1% for AC-PET images, respectively. The overall image clarity for AC-PET images was superior to NAC-PET images (81.8% vs 53% P=0.01). In conclusion, NAC-PET images appeared to be superior to AC-PET images in detecting superficial LN lesions. AC-PET images are superior to NAC-PET images with regard to the deep-seated LN lesions. Therefore, AC and NAC-PET images are complimentary to each other and require to be reviewed together in the evaluation of patients with lymphoma.

Significance of incidental fluorodeoxyglucose uptake in the parotid glands and its impact on patient management.

BACKGROUND AND OBJECTIVES: Minimal-to-low grade fluorodeoxyglucose (FDG) uptake in the parotid glands is regarded as a normal variant in a whole-body survey with FDG-PET. Not frequently, however, a relatively intense or asymmetric FDG uptake is encountered in the parotid glands. The aim of this study was to determine the causes and characteristics of this 'FDG accumulation of uncertain significance' in the parotid glands in patients without any known or suspected pathologies at the time of whole-body FDG-PET. In addition, we also examined patients in whom there was no documented evidence of parotid pathology before FDG-PET scan and a suspicion of disease involvement was first raised in the reports in view of focal uptake in the FDG-PET images. MATERIALS AND METHODS: A total of 25 patients with 49 PET examinations [46 PET and three PET/computed tomography (CT) scans] were identified from the retrospective examination of PET reports and were analyzed in this study. Only those cases with no earlier history of disease involvement of parotid gland or known parotid pathology before FDG-PET were selected for this analysis. These patients were selected from a population of patients with a known malignancy elsewhere who underwent conventional whole-body FDG-PET or PET/CT for staging, disease viability assessment, or treatment monitoring purposes and had demonstrated varying patterns of FDG uptake (unilateral, bilateral, symmetric, or asymmetric) in the parotid glands. FDG uptake in the parotid glands was reported to be of uncertain significance in the majority of these patients and further correlation was suggested in the PET reports. In five patients with asymmetric and focally enhanced FDG uptake, a suspicion of disease involvement was raised in the reports. The results of appropriate correlative investigations with MRI, low-dose nonenhanced attenuation CT images (based on PET/CT scans), and histopathology (in cases in which focal lesions were revealed by the anatomic imaging modalities and biopsy was performed) carried out subsequent to the FDG-PET scans were reviewed for a definitive conclusion with regard to the significance of the FDG uptake in the parotid glands in these patients. In the absence of any focal pathology, clinical and follow-up FDG-PET data were reviewed for a logical conclusion, which were available in a majority of these patients. Standardized uptake values (maximum) were calculated by generating a manual region of interest over FDG activity. The pattern and the intensity of the FDG uptake were correlated with the final diagnosis. RESULTS: In six of the 25 patients with diffuse and symmetrical FDG uptake no clearcut pathology was demonstrated by clinical or radiological examinations. Five patients of this subgroup also demonstrated associated enhanced FDG activity in the submandibular salivary glands. Nineteen patients (76%) demonstrated asymmetric FDG uptake. Among these, focally enhanced uptake was observed in seven patients (28% of the total number of patients and 36.8% of the patients who demonstrated asymmetric FDG uptake in the parotids). Twelve patients (48% of total patients and 63.2% of the patients who demonstrated asymmetric FDG uptake) demonstrated asymmetric and diffuse FDG uptake pattern. No revelation of disease either by the MRI or follow-up clinical and FDG-PET examinations was observed in patients with asymmetric diffuse uptake. Five of the seven patients, who had asymmetric focal uptake in one of the parotids, were found to have focal lesions in either correlative MRI or low-dose nonenhanced CT. The final diagnosis based upon histopathology revealed primary parotid tumors (e.g., Warthin's tumor and pleomorphic adenoma, which presented as FDG-avid parotid incidentaloma) or metastatic disease involvement. CONCLUSION: Both the pattern and intensity of FDG uptake have important implications for differential diagnosis in the salivary glands in whole-body FDG-PET. A bilaterally symmetrical increased uptake is usually physiological. An asymmetrical uptake, especially when focal, would warrant further radiological and histopathological correlation to rule out disease involvement. At times, this can lead to the detection of an asymptomatic hitherto unknown etiology, which would have been otherwise interpreted as a metastatic disease in the background of an existing malignancy in these patients; this is noteworthy as it may have a bearing on the subsequent management of these patients.

PET and PET/CT in Pediatric Gastrointestinal Tract Oncology.

PET and PET/CT imaging are increasingly used in pediatric oncology; however, their role is still evolving. Studies have shown an incremental impact of PET imaging on the management of childhood malignancies. Gastrointestinal tumors have low incidence in children and PET has proved useful in many of them. Overall, the published data support the exceptional diagnostic capability of PET and PET-CT imaging. This article presents insight through the available literature on pediatric gastrointestinal oncology.