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ABSTRACT: PurposeOur aim was to assess the diagnostic potential of 18F-FDG PET using partial volume correction and dual-time-point imaging in the assessment of solitary pulmonary nodules.
MethodsWe included 265 patients in this retrospective study (171 men; 94 women; age range, 41–92years). All had pulmonary nodules
on CT, and diagnosis was confirmed by biopsy or follow-up CT. All underwent whole body FDG PET, 60min after FDG injection.
Of the 265 patients, 255 underwent second FDG PET for chest 100min after injection. Maximum SUVs for nodules were calculated
from both scans. Partial volume correction for first time SUVs was applied, using coefficient factor. Malignancy was defined
using the following criteria: (1) Visual assessment; (2) First time SUV ≥ 2.5; (3) Partial volume corrected first time SUV ≥ 2.5;
(4) second time SUV ≥ 2.5; (5) Increase in SUV over time; (6) Increase or no change in SUV; (7) First time SUV ≥ 2.5 and/or
increase or no change in SUV.
ResultsBiopsy and follow-up revealed 72 malignant lung nodules and 193 benign nodules. Sensitivity, specificity and accuracy for
the five criteria were as follows: (1) 97, 58 and 68%; (2) 65, 92 and 85%; (3) 84, 91 and 89%; (4) 90, 80 and 83%; (5) 84,
95 and 92%; (6) 92, 92, and 92%; (7) 95, 90 and 91%, respectively.
ConclusionDual-time-point 18F-FDG PET has potential impact on improving the diagnostic accuracy for malignant lung nodules. Dual-time-point 18F-FDG PET imaging should be included in the clinical work-up of patients with pulmonary nodule.
European journal of nuclear medicine and molecular imaging 04/2012; 35(2):246-252. · 4.99 Impact Factor
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ABSTRACT: 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.
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.
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.
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.
Molecular imaging and biology: MIB: the official publication of the Academy of Molecular Imaging 10/2009; 12(3):233-9. · 2.47 Impact Factor
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ABSTRACT: Correction of the "partial volume effect" has been an area of great interest in the recent times in quantitative PET imaging and has been mainly studied with count recovery models based upon phantoms that incorporate hot spheres in a cold background. The goal of this research study was to establish a similar model that is closer to a biological imaging environment, namely hot spheres/lesions in a warm background and to apply this model in a small cohort of patients.
A NEMA phantom with six spheres (diameters 1-3.7 cm) was filled with (18)FDG to give sphere:background activity ratios of 8:1, 6:1, and 4:1 for three different acquisitions on a Philips Allegro scanner. The hot sphere SUVmax and the background average SUV were measured for calculation of recovery coefficients (RCs). Using the RCs, the lesion diameters, and the lesion:background ratio, the SUVmax of 64 lesions from 17 patients with biopsy proven lung cancer were corrected.
The RCs versus sphere diameters produced characteristic logarithmic curves for each phantom (RCs ranged from 80% to 11%). From a cohort of 17 patients with biopsy proven lung cancer, 64 lesions combined had a mean SUVmax of 7.0 and size of 2.5 cm. After partial volume correction of the SUVmax of each lesion, the average SUVmax increased to 15.5.
Hot spheres in a warm background more closely resemble the actual imaging situation in a living subject when compared to hot spheres in a cold background. This method could facilitate generation of equipment specific recovery coefficients for partial volume correction. The clinical implications for the increased accuracy in SUV determination are certainly of potential value in oncologic imaging.
Annals of Nuclear Medicine 05/2009; 23(4):341-8. · 1.50 Impact Factor
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ABSTRACT: Atherosclerosis is a dynamic inflammatory disorder. The biological composition and inflammatory state of an atherosclerotic plaque, rather than the degree of stenosis or its size are the major determinants of acute clinical events. A noninvasive technique to detect vulnerable atherosclerotic plaque is critically needed. FDG-PET/CT, a combined functional and structural whole-body imaging modality, holds great potential for this purpose. FDG uptake in large arteries has been frequently observed and is associated with cardiovascular risk factors. FDG accumulates in plaque macrophages and uptake is correlated with macrophage density. It is known that vascular FDG uptake and calcification do not overlap significantly and changes of FDG uptake are common, suggesting that FDG uptake may represent a dynamic inflammatory process. It has been reported that vascular FDG uptake can be attenuated by simvastatin in patients, and by the antiinflammatory drug probucol in rabbits. Vascular FDG uptake has been linked to cardiovascular events in some preliminary studies. Data from basic sciences, and animal and clinical studies support the emerging role of FDG-PET/CT in assessing atherosclerosis in large arteries in humans.
European Journal of Nuclear Medicine 12/2008; 36(1):144-51. · 4.53 Impact Factor
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ABSTRACT: Our aim was to assess the diagnostic potential of (18)F-FDG PET using partial volume correction and dual-time-point imaging in the assessment of solitary pulmonary nodules.
We included 265 patients in this retrospective study (171 men; 94 women; age range, 41-92 years). All had pulmonary nodules on CT, and diagnosis was confirmed by biopsy or follow-up CT. All underwent whole body FDG PET, 60 min after FDG injection. Of the 265 patients, 255 underwent second FDG PET for chest 100 min after injection. Maximum SUVs for nodules were calculated from both scans. Partial volume correction for first time SUVs was applied, using coefficient factor. Malignancy was defined using the following criteria: (1) Visual assessment; (2) First time SUV > or = 2.5; (3) Partial volume corrected first time SUV > or = 2.5; (4) second time SUV > or = 2.5; (5) Increase in SUV over time; (6) Increase or no change in SUV; (7) First time SUV > or = 2.5 and/or increase or no change in SUV.
Biopsy and follow-up revealed 72 malignant lung nodules and 193 benign nodules. Sensitivity, specificity and accuracy for the five criteria were as follows: (1) 97, 58 and 68%; (2) 65, 92 and 85%; (3) 84, 91 and 89%; (4) 90, 80 and 83%; (5) 84, 95 and 92%; (6) 92, 92, and 92%; (7) 95, 90 and 91%, respectively.
Dual-time-point (18)F-FDG PET has potential impact on improving the diagnostic accuracy for malignant lung nodules. Dual-time-point (18)F-FDG PET imaging should be included in the clinical work-up of patients with pulmonary nodule.
European journal of nuclear medicine and molecular imaging 03/2008; 35(2):246-52. · 4.99 Impact Factor
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ABSTRACT: In this review, we describe the current approaches used for quantitative assessment of regional and global function with positron emission tomography (PET) imaging (combined with structural imaging modalities) with emphasis on both research and clinical applications of this powerful approach. We particularly refer to the impact of such measurements in assessing physiological processes such as aging and measuring response to treatment in serious disorders such as cancer. Although a multitude of methods has been described in literature, the optimal approaches that are both accurate and practical in clinical settings need to be defined and refined. Standardized uptake value (SUV) continues to be the most widely used index in the current practice. Calculating SUV at a single time point and assigning standard regions of interest are inadequate and suboptimal for the purposes adopted by the medical community. The concepts of partial volume correction for measured values in small lesions, dual-time point and delayed PET imaging, and global metabolic activity for assessment of various stages of disease may overcome deficiencies that are associated with the current quantitative (ie, SUV) techniques. Serious consideration of these concepts will enhance the role and reliability of these quantitative techniques, and therefore compliment the World Health Organization or the Response Evaluation Criteria in Solid Tumors (RECIST) criteria for managing patients with cancer and other disorders, including physiological states such as aging and serious diseases such as atherosclerosis and neurological diseases. We also introduce the concepts that allow for segmentation of various structural components of organs like the brain for accurate measurement of functional parameters. We also describe complicated kinetic modeling and methodologies that have been used frequently for assessing metabolic and pharmacological parameters in the brain and other organs. Simplified quantitative techniques based on these concepts are described, but should be validated against the kinetic models to test their role as practical tools.
Seminars in Nuclear Medicine 06/2007; 37(3):223-39. · 4.31 Impact Factor
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European journal of nuclear medicine and molecular imaging 05/2007; 34(4):615. · 4.99 Impact Factor
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ABSTRACT: In this article, we report quantitative preliminary data obtained from retrospective analysis of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) and combined PET-computed tomography (PET/CT) examinations in subjects ages 3 to 84 years pertaining to changes in the metabolism of skin, subcutaneous adipose tissue, visceral adipose tissue, and skeletal muscle with age, as well as age-related changes in skeletal muscle attenuation. We also propose a new method for identifying hypermetabolic brown fat on FDG-PET. Finally, we present a review of the literature regarding reported age-related structural and functional changes that occur in skin, fat, and skeletal muscle. Using FDG-PET, We evaluated 213 subjects for changes in the metabolism of skin, adipose tissue, and skeletal muscle with aging. Thirty-two separate subjects were chosen to measure maximum standardized uptake value (SUV) of hypermetabolic brown fat on dual-time point PET imaging. Finally, 15 subjects evaluated by PET/CT were selected to measure changes in metabolism and attenuation of skeletal muscle, and changes in metabolism of adipose tissue with aging. We found that skin, fat, and skeletal muscle all demonstrate significant (P < 0.05) increases in SUV with increasing age on PET imaging. Dual-time point PET imaging demonstrates increasing FDG uptake of hypermetabolic brown fat in various regions studied. Finally, our PET/CT studies revealed statistically insignificant (P > 0.05) decreases in SUV of adipose tissue with aging and the opposite trend in skeletal muscles (P > 0.05). Skeletal muscle attenuation in the various regions studied was found to significantly decrease with age (P < 0.05). Our study shows notable trends in metabolism and attenuation of skeletal muscle and metabolism of skin and adipose tissue that occur with normal aging. We hope that the methodologies and data we present here will serve as a useful starting point for those interested in conducting future prospective research on age-related changes in these structures.
Seminars in Nuclear Medicine 05/2007; 37(3):195-205. · 4.31 Impact Factor
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ABSTRACT: Physicians have long told their patients that the doctor's job is to help patients "get as old as they can." As physicians, we have been aided in this objective by many other scientists in other disciplines. The entity of aging and its related changes blends imperceptibly with a variety of age-related diseases. However, these entities do appear to be separate though interrelated. Curing disease is important and a goal that we all work toward to add years to life expectancy. Here, we consider aging as it affects the heart and great vessels and as it serves to influence and support, if not cause, age-related cardiac diseases. This relationship is drawn as cardiac mechanics, hemodynamics, perfusion, metabolism and innervation, anatomy, and pathophysiology are each considered. The effects of aging are presented in 2 sections related to the early and recent "spikes" in aging related information. The latter is largely based in recent developments in chemistry, genetic engineering, molecular biology and the new imaging methods. The purpose of this manuscript is to present these new imaging methods, especially PET, and their impact on the second "spike." This is emphasized particularly in the second half of this review. As a method of demonstrating these imaging tools and their finest potential application, we decided to "showcase" atherosclerosis as the age-related disease for which these methods have made their greatest impact, for which yet more is promised, and for which the influence on longevity is most obvious. The application of positron emission tomography and other imaging methods to the characterization and image identification of atherosclerotic plaques and particularly the "vulnerable" plaque is emphasized. Yet, even with the eradication of coronary disease, the potential for very long life would not be likely. Only with the identification and eradication of the causative factors of aging can this possibility have a chance of becoming reality.
Seminars in Nuclear Medicine 04/2007; 37(2):120-43. · 4.31 Impact Factor
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ABSTRACT: FDG-PET is of limited use in patients with early-stage disease without nodal or distant metastases (stage I-II), because sentinel node biopsy is much more sensitive in detecting microscopic lymph node metastases. Because of the high tumor-to-background ratio, FDG-PET can highlight metastases at unusual sites that are easily missed with conventional imaging modalities. PET has been shown to have a strong role in detecting metastatic disease. FDG-PET is more sensitive than CT for detecting metastatic lesions in skin, lymph nodes, and abdomen, but CT is equivalent to or more sensitive than FDG-PET for detecting small pulmonary lesions. FDG-PET identifies the location and number of metastatic lesions in stage III and IV disease and therefore is important for surgical planning. Most of the false-negative FDG-PET results are caused by micrometastases and lesion smaller than 10 mm. Postsurgical inflammation, other inflammatory lesions, and some benign tumors cause some false-positive FDG-PET results.
Radiologic Clinics of North America 02/2005; 43(1):23-33. · 2.59 Impact Factor
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ABSTRACT: The number of fluorodeoxyglucose PET applications is increasing. In the process of reading fluorodeoxyglucose-PET scans, nuclear medicine physicians encounter a wide variety of normal findings, which must be recognized to determine the best management for patients. It is important to recognize and understand normal variants to avoid misinterpretation of more serious pathology. This article reviews different patterns of physiologic fluorodeoxyglucose uptake including changes with age.
Radiologic Clinics of North America 12/2004; 42(6):1063-81, viii. · 2.59 Impact Factor
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ABSTRACT: 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.
Hellenic journal of nuclear medicine 12(3):218-22. · 0.81 Impact Factor
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ABSTRACT: 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.
Hellenic journal of nuclear medicine 12(1):5-9. · 0.81 Impact Factor
