Showing papers in "Annals of Nuclear Medicine in 2009"
TL;DR: FDG-PET/CT represents the inflammatory activity in large joints in patients with RA accurately and sensitively and may be helpful for early evaluations of the extent of RA throughout the whole body including high risk lesion of atlanto-axial joint.
Abstract: Fluorodeoxyglucose (FDG) uptake in joint lesions in patients with rheumatoid arthritis (RA) reportedly represents the degree of synovial inflammation. Most previous studies have focused on small joints, and the application of whole-body positron emission tomography (PET) combined with computed tomography (CT) (PET/CT) for the evaluation of inflammatory activity in large joints has not been well studied. Eighteen patients with RA underwent FDG-PET/CT. FDG uptake in the knee, hip, carpal, wrist, elbow, shoulder, and atlanto-axial joint (total of 13 joints) and in the axillary lymph nodes was evaluated by calculating the maximum standardized uptake value (SUVmax) and the visual uptake scores as follows: 0, no uptake; 1, slight uptake; 2, moderate uptake (same as in liver); 3, higher than in liver; 4, highest uptake. The number of painful/swollen joints, the white blood cell (WBC) count, and the C-reactive protein (CRP) level were also evaluated. Whole-body FDG-PET/CT delineated large-joint lesions in patients with RA, and the metabolic activity of inflammation was accurately overlaid on the joint anatomy. The total FDG score for all 13 joints was significantly correlated with the CRP level (r = 0.653, p 0.05). The WBC count was not correlated with any other parameter. The mean number of joints per patient with an FDG uptake score of 2 or more was significantly larger than the mean number of painful/swollen joints (6.2 ± 3.3 vs. 3.1 ± 2.7, n = 18, p < 0.01) and both parameters were strongly correlated (r = 0.588, p < 0.01, n = 18). Also, FDG uptake score and SUV of painful/swollen joints were significantly higher than these of not painful/swollen joints. FDG uptake was significantly different from patients of remission and patients of active arthritis. Uptake in the atlanto-axial joint was observed in five (mostly asymptomatic) patients (5/18, 28%), and the uptake score was significantly correlated with the total FDG score (r = 0.669, p < 0.01, n = 18). The axillary lymph nodes score was correlated with the arm joints score. FDG-PET/CT represents the inflammatory activity in large joints in patients with RA accurately and sensitively and may be helpful for early evaluations of the extent of RA throughout the whole body including high risk lesion of atlanto-axial joint. Furthermore, the visual FDG uptake score may be useful for evaluating arthritis in large joints.
114 citations
TL;DR: Hot spheres in a warm background more closely resemble the actual imaging situation in a living subject when compared to hot sphere in a cold background, which could facilitate generation of equipment specific recovery coefficients for partial volume correction.
Abstract: Objectives
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.
97 citations
TL;DR: FDG PET/CT is more accurate than CI regarding clinical staging and re-staging of patients with rhabdomyosarcomas and the overall TNM staging and M staging accuracies of FDGPET/CT were significantly higher than that of CI.
Abstract: The current study was conducted to compare the diagnostic accuracy between 18F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT), and conventional imaging (CI) for the staging and re-staging of patients with rhabdomyosarcomas. Thirty-five patients who underwent FDG PET/CT prior to treatment were evaluated retrospectively. CI methods consisted of 99mTc-hydroxymethylene diphosphonate bone scintigraphy, chest radiograph, whole body CT, and magnetic resonance imaging of the primary site. The images were reviewed and two boardcertified radiologists reached a diagnostic consensus. Tumor stage was confirmed by histological examination and/or follow-up examinations. Interpretation on the basis of FDG PET/CT, and CI, diagnostic accuracies of the T and N stages were similar. Using FDG PET/CT, the M stage was correctly assigned in 31 patients (89%), whereas the accuracy of CI in M stage was 63%. TNM stage was correctly assessed with FDG PET/CT in 30 of 35 patients (86%) and with CI in 19 of 35 patients (54%). The overall TNM staging and M staging accuracies of FDG PET/CT were significantly higher than that of CI (P < 0.01). FDG PET/CT is more accurate than CI regarding clinical staging and re-staging of patients with rhabdomyosarcomas.
94 citations
TL;DR: FDG PET/CT could distinguish pulmonary artery sarcoma from pulmonary embolism based on the SUVmax value, and the locations in lesions between the three groups (right, left and bilateral) or background uptakes were not significant.
Abstract: The purpose of this study was to evaluate the usefulness of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in differentiating pulmonary artery sarcoma from pulmonary embolism. We evaluated three patients with pulmonary artery sarcoma and 10 patients with proximal pulmonary embolism (6 men and 7 women, ranging in age from 35 to 94 years). All the patients had evidence of perfusion defects in their proximal pulmonary arteries on contrast-enhanced computed tomography (CT) scans performed prior to PET/CT. The maximum standardized uptake value (SUVmax) of FDG uptake in all the lesions was measured using PET/CT. The location of lesions, background uptake or thrombi in the legs were evaluated in both groups as basic characteristics. The mean SUVmax of the pulmonary artery sarcomas (7.63 ± 2.21, n = 3) and the pulmonary embolisms (2.31 ± 0.41, n = 10) were significantly different (P < 0.05). The mean times between the initial contrast-enhanced CT scan and PET/CT scan were similar in both groups (P = 0.7804). The differences in the locations in lesions between the three groups (right, left and bilateral) or background uptakes were not significant. FDG PET/CT could distinguish pulmonary artery sarcoma from pulmonary embolism based on the SUVmax value.
89 citations
TL;DR: The degree of F-18 FDG accumulation that constitutes an abnormal level referring to blood parameters depends on the patient’s age and serum CRP level, both with and without malignancy.
Abstract: In clinical positron emission tomography (PET) studies for oncology, it is occasionally required to differentiate a diffuse increase in bone marrow (BM) F-18 fluoro-2-deoxyglucose (FDG) uptake due to the involvement of malignancy or hematopoietic disease and that due to the administration of hematopoietic cytokines, an inflammation reaction, or stimulation by some types of malignancy. The objectives of this study were to clarify the relationships between BM F-18 FDG uptake and blood parameters as well as age, and also to determine the degree of F-18 FDG accumulation that constitutes an abnormal level referring to blood parameters. Records of 65 patients, 32 with benign diseases and 33 with malignancies without metastasis in bone and liver until a half year after the PET examination, were analyzed retrospectively. Regions of interest were placed on the liver and the lower thoracic and lumbar vertebrae to measure the standardized uptake value (SUV), and vertebral SUVs were averaged as the BM SUVmean. The BM SUVmean was divided by the liver SUV to calculate the BM/liver ratio. The relationships among the BM SUVmean, or BM/liver ratio, and blood parameters and age were tested using multiple regression analysis. In both patients with and without malignancy, a multiple regression model using the BM/liver ratio showed a higher coefficient of determination value than that using the BM SUVmean, indicating that the correction by the liver SUV reduced the interindividual variation in the BM SUVmean. The BM/liver ratio was negatively correlated with age (β = −0.41 and −0.43, respectively) and positively correlated with serum C-reactive protein (CRP) level (β = 0.39 and 0.46, respectively) in both groups of patients. Every patient with benign disease who had a ratio greater than or equal to 1 had an increased CRP level. The BM F-18 FDG uptake depends on the patient’s age and serum CRP level, both with and without malignancy. A BM F-18 FDG uptake greater than or equal to that of the liver may indicate BM activation.
88 citations
TL;DR: A variety of scintigraphic patterns can be found in patients with ectopic gastric mucosa undergoing 99mTc pertechnetate scintigraphy depending on the location and size of the ectopic tissue.
Abstract: Technetium-99m ((99m)Tc) pertechnetate scintigraphy in a child with acute gastrointestinal bleeding of unknown origin suggests ectopic gastric mucosa caused by Meckel's diverticulum or gastrointestinal duplication cysts Our objective was to define the patterns of scintigraphic findings likely to be encountered in patients with ectopic gastric mucosa with illustrative cases and to review the literature Fifty children (age 1 year to 14 years) were evaluated for ectopic gastric mucosa using (99m)Tc pertechnetate scintigraphy Functioning ectopic gastric mucosa was detected in eight patients with Meckel's diverticula and three patients with bowel duplication Three patients showed atypical findings on scintigraphy which were perforated appendix, calyceal stasis, and regional enteritis Ectopic functioning gastric mucosa in Meckel's diverticulum is visualized simultaneously with the stomach, whereas in intestinal duplications tracer activity can be visualized in the dynamic sequence or before gastric tracer visualization in an irregular pattern A variety of scintigraphic patterns can be found in patients with ectopic gastric mucosa undergoing (99m)Tc pertechnetate scintigraphy depending on the location and size of the ectopic tissue Also, acquisition of delayed images is useful when the initial images are equivocal in children
78 citations
TL;DR: The clinical significance of diffuse plus focal uptake of the thyroid on FDG-PET is not well known; it may also be associated with an increased risk of malignancy when compared with a diffuse uptake pattern only.
Abstract: Significant uptake of the thyroid is often identified as an incidental finding on whole-body F18-fluorodeoxyglucose positron emission tomography (FDG-PET) for non-thyroid disease. Sometimes, it is a dilemma for radiologists to interpret clinical significance of thyroid uptake and give adequate recommendation for further evaluation. In general, diffuse uptake of the thyroid glands on FDG-PET is considered to be benign and very likely secondary to thyroiditis and/or hypothyroidism; a further correlation or investigation of the thyroid function and/or ultrasound is helpful. Focal uptake of the thyroid on FDG-PET is defined as an incidentaloma, which is more clinically significant owing to its high risk of malignancy ranging 25–50%. Although maximum standardized uptake value and corresponding computed tomographic finding may help to differentiate benign from malignant lesion, a cytological diagnosis is often advised. The clinical significance of diffuse plus focal uptake of the thyroid on FDG-PET is not well known; it may also be associated with an increased risk of malignancy when compared with a diffuse uptake pattern only.
74 citations
TL;DR: F-FDG PET-CT can help characterize various thymic lesions noted on conventional imaging modalities, however, larger prospective studies are further required to substantiate these findings.
Abstract: Background
The resectability and survival may be improved in thymoma and thymic carcinoma with multimodality therapy. Various diagnostic imaging modalities are required for accurate diagnosis and preoperative staging of thymic masses. The present prospective study was planned to evaluate if Fluorodeoxyglucose (FDG) PET-CT can help differentiate various thymic lesions noted on conventional imaging modalities.
74 citations
TL;DR: The results demonstrate that [11C]CHIBA-1001 is a suitable radioligand to use in clinical trials for imaging α7 nAChRs in the human brain, providing acceptable dosimetry and pharmacological safety at the dose required for adequate PET imaging.
Abstract: Objective
4-[11C]methylphenyl 2,5-diazabicyclo[3.2.2]nonane-2-carboxylate ([11C]CHIBA-1001), a 4-methyl-substituted derivative of the selective α7 nicotinic acetylcholine receptor (α7 nAChR) partial agonist 4-bromophenyl 1,4 diazabicyclo[3.2.2]nonane-4-carboxylate (SSR180711), is a potential radioligand for mapping α7 nAChRs in the brain by positron emission tomography (PET). In this study, we performed preclinical and first clinical PET studies using [11C]CHIBA-1001 for imaging α7 nAChRs in the human brain.
73 citations
TL;DR: FDG-PET imaging of osteosarcoma correlates positively with histologic response to neoadjuvant chemotherapy, suggesting SUV2 and SUV2:1 could be feasible as non-invasive surrogate predictors of response in osteosARcoma patients.
Abstract: The objective of this study is to evaluate the utility of positron emission tomography (PET) with 2-deoxy-[18F] fl uoro-D-glucose (FDG) in the assessment of the chemotherapy response of osteosarcoma when compared with the degree of necrosis determined histologically. Whole-body FDG-PET scan was performed on 11 patients with osteosarcoma. All patients received neoadjuvant chemotherapy. The tumor size changes on magnetic resonance imaging; FDG-PET standardized uptake values prior to (SUV1) and following (SUV2) chemotherapy were analyzed and correlated with response to chemotherapy as assessed using histopathology in surgically excised tumors. Nine patients underwent FDG-PET scan both prior to and following neoadjuvant chemotherapy. The remaining two patients were examined only prior to surgery. Histologically, five patients had a good histologic response to chemotherapy (≧90% necrosis). The changes in tumor size did not correlate with histologic response (P > 0.05). SUV2 with good response was significantly lower than that with poor response (1.93 ± 0.50, 5.86 ± 2.55, respectively). Both the positive and negative predictive values of the SUV2 of less than 2.5 for a good response were 100%. Patients with good response showed a significantly higher ratio of SUV2 to SUV1 (SUV2:1) than patients with poor response (0.74 ± 0.11, 0.26 ± 0.39, respectively, P < 0.05). The positive and negative predictive values of SUV2:1 ≤ 0.5 for good and poor responses were 80% and 100%, respectively. FDG-PET imaging of osteosarcoma correlates positively with histologic response to neoadjuvant chemotherapy. SUV2 and SUV2:1 could be feasible as non-invasive surrogate predictors of response in osteosarcoma patients.
71 citations
TL;DR: FDG-PET/CT with additional SUVmax analysis improves the diagnostic accuracy of adrenal lesions in cancer patients and differentiating between adrenal benign and malignant lesions.
Abstract: Objective
To investigate whether integrated fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) can differentiate benign from adrenal malignant lesions on the basis of maximum standardized uptake value (SUVmax), tumor/liver (T/L) SUVmax ratio, and CT attenuation value (Hounsfield Units; HU) of unenhanced CT obtained from FDG-PET/CT data.
TL;DR: The use of respiratory trigger induced rather variable but overall consistent increases in SUV, and this could lead to an SUV values cut-off revision, and may have an impact on smaller lesions detection.
Abstract: Respiratory gated PET/CT (positron emission tomography/computed tomography) of the lung is expected to increase the accuracy of quantitative determinations in lesional activities, regardless of the gating method used; reasonably, respiratory gating should increase standard uptake value (SUV; and possibly decrease lesional size), on the basis of the reduction of the “smearing effect.” However, literature data are very limited, particularly for in vivo studies. The objective of this article is to test the SUV variations in a large group of lung lesion studies. A group of 26 consecutive positive studies (21 men, 5 women, age 36-84, mean 68), performed on patients referred to our institution for known or suspected lung cancer, are examined. All studies were performed both with conventional PET/CT total body scan and with Real-Time Position Management (RPM) triggered selective gated study of the thorax. Four studies were considered technically unsatisfactory and were discarded; the remaining 22 studies are the object of this work. Max lesional SUVs were evaluated in both settings by semi-automated algorithms; for the gated studies, both values of the bin that showed more relevant variations from the clinical routinary study (“best bin”) and an average value that was calculated over all bins were determined. Results were compared on a one-to-one basis. In conventional, SUV showed a mean ± standard deviation (SD) value of 9.2 ± 6.9 (range 0.9–26). In the averaged gated studies, the mean ± SD value was 13.4 ± 11.7 (range 1.4–47); in the “best bin” dataset the mean ± SD was 14.9 ± 12.9, ranging from 1.6 to 53.1. In general, the use of respiratory trigger induced rather variable but overall consistent increases in SUV. If the percentage variations in the average trigger dataset are considered, there is an average increase of +60%, SD ± 97 (P < 0.05). Similar results are found in the “best bin” dataset, the average percentage increase in SUV values being +77.2% (SD ± 04.6). In lung cancer, triggering procedures increase the signal to noise ratio. The increase in SUV determined by gating is very variable, but generally relevant. This could lead to an SUV values cut-off revision, and may have an impact on smaller lesions detection.
TL;DR: Integrated PET/CT improves the PPV of regional LNs when compared with CECT, and a comparison of the two CECT protocols revealed fewer false-positive LNs in protocol B, but slightly lower sensitivity in Protocol B than in Protocol A.
Abstract: To assess whether integrated fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) can improve the diagnostic accuracy of metastatic regional lymph nodes (LNs) in esophageal cancer compared with contrast enhanced CT (CECT). We examined 180 consecutive patients with esophageal cancer by integrated PET/CT between April 2006 and March 2007. Eighteen patients (M:F 14:4) underwent radical esophagectomy after evaluations by PET/CT and CECT of 5–7-mm-thick slices 70–80 s after injection. Regional LNs of esophageal cancer were retrospectively reviewed on CECT images by two blinded evaluators on the basis of the following cutoff sizes: 7 mm for all regional LNs (Protocol A), 10 mm for paratracheal LNs (Protocol B), and 7 mm for others. In addition, the maximum standardized uptake value (SUVmax) on PET/CT was evaluated for positive uptake by LNs. Of 210 LNs excised at surgery, 25 were positive and 185 were negative for metastasis at pathology. The PET/CT images identified 15 true-positive and 184 truenegative LNs, whereas CECT identified 15 true positives and 176 true negatives in Protocol A, and 14 true positives and 180 true negative in Protocol B. The sensitivity, specificity, accuracy, positive, and negative predictive values of PET/CT were respectively 60.0%, 99.5%, 94.8%, 93.8%, and 94.8%, whereas those of CECT were 60.0%, 95.1%, 91.0%, 62.5%, and 94.6% (Protocol A) and 56.0%, 97.3%, 92.4%, 73.7%, and 94.2% (Protocol B). A comparison of the two CECT protocols revealed fewer false-positive LNs in Protocol B, but slightly lower sensitivity in Protocol B than in Protocol A. Substantial numbers of false-positive LNs were determined by CECT in the paratracheal regions (6 of 9, 66.7%) and CECT revealed central necrosis in 4 of 15 (26.7%) true-positive LNs > 1.8 cm. The mean SUVmax on PET/CT was 2.9 (range 1.7–5.5) in true-positive LNs. The smallest LN metastasis detectable by PET/CT was 6 mm. Integrated PET/CT improves the PPV of regional LNs when compared with CECT.
TL;DR: Increased ovarian or endometrial uptake may cause a dilemma in the interpretation of whole body F18-fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging or even misdiagnosis of malignant disease in postmenopausal patients.
Abstract: Increased ovarian or endometrial uptake may cause a dilemma in the interpretation of whole body F18-fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging or even misdiagnosis of malignant disease. Knowledge of benign FDG uptake of the ovaries and uterus is important for daily practice of nuclear medicine radiologists. Increased uptake in the ovaries or uterus indicates a pathologic or neoplastic process in postmenopausal patients. In premenopausal women, increased ovarian or endometrial uptake can be functional or malignant. Benign functional uptake of premenopausal ovaries or uterus is related to the menstrual cycle; therefore, information about the patient’s menstrual status is crucial for interpretation. In addition, correlation with computed tomography (CT), especially diagnostic CT acquired at the same time of PET/CT is very useful in clarifying the location of the uptake and the existence or disappearance of the discrete lesion. Increased ovarian uptake may also be identified in histologically different benign tumor entities. Nonmenstrual-related endometrial uptake may be present in many benign diseases as well.
TL;DR: A SISCOM technique of ictal and interictal SPECT images provides higher predictive value of good surgical outcome and more reliability on the diagnosis of the epileptogenic focus than side-by-side comparison in medically intractable partial epilepsy.
Abstract: Objective
A multicenter prospective study was performed to assess the additional value of a subtraction ictal SPECT coregistered to MRI (SISCOM) technique to traditional side-by-side comparison of ictal- and interictal SPECT images in epilepsy surgery.
TL;DR: Focal uptake pattern and high max SUV may be helpful in differentiating benign and malignant nodules on FDG PET/CT, and for lesions with increased FDG uptake of thyroid, US examination should be recommended.
Abstract: To evaluate the usefulness of maximum standard uptake value (max SUV) calculated from F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) examination and findings from ultrasonographic (US) examination on incidentally detected thyroid FDG uptake on FDG PET/CT. We collected and reviewed FDG PET/CT images performed at our institution from March 2005 to March 2008. This study included 190 subjects with increased FDG uptake of thyroid gland who later underwent thyroid US and histological examinations. Of these subjects, the uptake pattern on FDG PET/CT was classified as either diffuse or focal. The FDG uptake pattern, max SUV, and US findings were evaluated and correlated with the histological results. In the focal FDG uptake pattern cases (n = 148), the mean max SUV of malignant cases was higher than that of benign cases (5.93 ± 5.35 vs. 3.47 ± 2.89). Of the diffuse FDG uptake cases (n = 42), nodules were detected in 25 subjects (59.5%) by US examination. Thyroid nodules were well characterized on US studies, and combined findings of suspicious US features or high max SUV of focal FDG uptake lesion increased sensitivity, PPV, NPV, and accuracy. Focal uptake pattern and high max SUV may be helpful in differentiating benign and malignant nodules on FDG PET/CT. However, US examination provides further information, and for lesions with increased FDG uptake of thyroid, US examination should be recommended.
TL;DR: Considering the rapid flow of 99mTc-antimony sulfide colloid in the study, lymphoscintigraphy imaging can be completed in the nuclear medicine department without any delay in sending the patient back to the surgery department.
Abstract: We assessed the need for delayed lymphoscintigraphy imaging for sentinel lymph node (SLN) biopsy in stage I and II breast cancer patients using intradermal injection of 99mTc-antimony sulfide colloid. Seventy-five patients with early-stage breast cancer were included in our study. Periareolar intradermal injections of 0.5 mCi/0.2 mL 99mTc-antimony sulfide colloid was used for the patients without previous excisional biopsy (45 patients). Two intradermal injection of 0.5 mCi/0.2 mL 99mTc-antimony sulfide colloid was used on each side of the dermal incision in patients with the history of excisional biopsy (30 patients). Anterior and lateral static images were taken at 2 min. If SLN was not visualized, delayed imaging at 5, 10, 30, 60, 90, 150, and 180 min was done (till the visualization of the SLN or 180 min). SLN was performed by the combination of gamma probe and blue dye during surgery. Sentinel lymph node detection rate was 96% (72/75). SLNs were detected on the immediate (2 min) images in 55 (73.33%) patients. In the remaining patients, the SLNs were detected first on the 5-, 10-, and 30-min images in 10 (13/33%), 5 (6.66%), and 2 (2.66%) patients, respectively. In three patients (4%), SLN was not detected by lymphoscintigraphy even on 180-min images. During surgery, SLN was not detected in these three patients either. Considering the rapid flow of 99mTc-antimony sulfide colloid in our study, lymphoscintigraphy imaging can be completed in the nuclear medicine department without any delay in sending the patient back to the surgery department. Thirty minutes after radiotracer injection seems to be the optimal time for lymphoscintigraphy and delayed imaging beyond 30 min would not be necessary.
TL;DR: It is shown that LPS with Tc-99m-MAA represents a diagnostic method of continuing value for PE, and LPS still has a place in the diagnostics of PE and is irreplaceable in several rare indications as described earlier.
Abstract: Lung perfusion scintigraphy (LPS) with technetium-99m-labeled macro-aggregates of albumin (Tc-99m-MAA) is well established in the diagnostic of pulmonary embolism (PE). In the last decade, it was shown that single-photon emission computer tomography (SPECT) acquisition of LPS overcame static scintigraphy. Furthermore, there are rare indications for LPS, such as preoperative quantification of regional lung function prior to lung resection or transplantation, optimization of lung cancer radiation therapy, quantification of right-left shunt, planning of intra-arterial chemotherapy, and several rare indications in pediatrics. Moreover, LPS with Tc-99m-MAA is a safe method with low radiation exposure. PE can also be diagnosed by spiral computer tomography (CT), ultrasound, magnetic resonance angiography, or pulmonary angiography (PA, former gold standard). The present review considers all these methods, especially spiral CT, and compares them with LPS with respect to sensitivity and specificity and gives an overview of established and newer publications. It shows that LPS with Tc-99m-MAA represents a diagnostic method of continuing value for PE. In comparison with spiral CT and/or PA, LPS is not to be defeated as mentioned also by the most actual Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II reports. This applies in particular to chronic or recurring embolisms, whereas currently spiral CT may be of greater value for major or life-threatening embolisms. At present, LPS cannot be replaced by other methods in some applications, such as pediatrics or in the quantification of regional pulmonary function in a preoperative context or prior to radiation therapy. LPS still has a place in the diagnostics of PE and is irreplaceable in several rare indications as described earlier.
TL;DR: 90Y BECT imaging can be used for patient assessment without modifying current treatment procedures and shows the highest resolution and lowest uncertainty.
Abstract: This study demonstrates images obtained by 90Y bremsstrahlung emission computed tomography (BECT), and characterizes the system performance of gamma cameras. 90Y BECT images of phantoms were acquired using a gamma camera equipped with a medium energy general purpose parallel-hole collimator. Three energy window widths of 50% (57–94 keV) centered at 75 keV, 30% (102–138 keV) at 120 keV, and 50% (139–232 keV) at 185 keV were set on a 90Y bremsstrahlung spectrum. The images obtained with three energy windows were reconstructed using filtered back projection (FBP) and ordered subsets expectation maximization (OSEM) methods. The images of the sum window were obtained by fusing the images of the 75, 120, and 185 keV windows. The OSEM method improved the full width at half maximum by 20% and the standard deviation by 9% compared with the FBP method. BECT displayed 90Y biodistribution and quantified 90Y activity. BECT images obtained with OSEM method using the 120 keV window showed the highest resolution and lowest uncertainty. The sum window showed the highest sensitivity, while its resolution was 10% inferior to that of the 120 keV window. One whole-body image can be taken over 100 min using the sum window. An absorber to cover the body surface reduced background by 30%. 90Y BECT imaging can be used for patient assessment without modifying current treatment procedures.
TL;DR: The likelihood of lymph node metastasis increases with an increase of the SUV of a primary lung cancer and the number of the metastatic lymph nodes and pathological n stages.
Abstract: Purpose
To evaluate the relationship between SUVmax of primary lung cancers on FDG-PET and lymph node metastasis.
TL;DR: Although delayed PET/CT scan enhances the difference of FDG uptake between FDG-avid NSCLC and benign lesions, and the use of delayed SUVmax > 5.5 appears to improve the differentiation of these hypermetabolic lesions compared with an early scan, careful interpretation and management for correct differentiation are still required.
Abstract: Objective
The aim of this study is to clarify the difference of F-18 FDG uptake kinetics between FDG-avid non-small-cell lung cancer (NSCLC) and benign lesions associated with various etiologies on dual-time point PET/CT scan, and to determine the optimal parameter for differentiation.
TL;DR: The use of automated ROI may eliminate the interoperator and interfacility variability in ROI setting and improve objectivity and reproducibility and is expected to enhance the clinical diagnosis.
Abstract: We have developed a method to automatically set regions of interest (ROI) (automated ROI) on cerebral blood flow single-photon emission computed tomography (SPECT) images with morphological information specific to the subjects. The objective was to set ROIs automatically without losing individual morphological information in the SPECT images and then evaluate its validity and clinical applicability. We constructed the volume of interest (VOI) template on the standardized brain generated by NEUROSTAT to determine the regions for ROIs to be set. Assuming patients with cerebral vascular disease, the VOI template was constructed so that the ROIs were drawn for the major vascular regions and 17 regions in total within the hemisphere, basal ganglia, thalamus, cerebellar cortex, cerebellar vermis, and pons. By comparing the major vascular occlusion models, the accuracy of region setting by the VOI template was evaluated for validation. Using the anatomical standardization of NEUROSTAT and inverse transformation, the automated ROI transformed the VOI template into the individual brain shape and then the VOI template was extracted from each slice to determine ROIs. An evaluation was made by visually investigating the effect of a different image quality and cerebral blood flow tracers using brain phantom and clinical data. The regional cerebral blood flow (rCBF), determined by the manual setting method of ROI (manual ROI) and automated ROI, was compared. We also compared automated ROI with other morphological images using clinical data. The VOI templates accurately showed the region with the reduced blood flow in the major vascular occlusion model, which validated the proper ROI setting. The brain phantom study demonstrated that ROI settings were least influenced by matrix size, image quality, and image rotation. The observation with the clinical data also indicated that the variation in cerebral blood flow tracers little affected the ROI settings. The comparison with manual ROI revealed a strong correlation between the two ROI settings, and the mean values within both ROIs were similar. The comparative evaluation with morphological images, obtained by magnetic resonance imaging (MRI), verified the accurate setting of ROI. The automated ROI achieved successful automatic ROI settings without distorting individual SPECT images. The automated ROI is not affected by the differences in the image quality or the cerebral blood flow tracers, which suggests versatile applicability. Thus, the use of automated ROI may eliminate the interoperator and interfacility variability in ROI setting and improve objectivity and reproducibility. It also allows comparative evaluation at the same transverse level with images acquired with other modalities such as MRI and is expected to enhance the clinical diagnosis.
TL;DR: Fluorodeoxyglucose positron-emission tomography has the potential to detect various kinds of malignant tumors in cancer screening test, and the overall detection rate of PET/CT was 0.8%.
Abstract: This study was performed to evaluate the clinical value of 18F-fluorodeoxyglucose (FDG) positron-emission tomography (PET)/computed tomography (CT) for cancer screening in Korean asymptomatic people. Between February 2004 and December 2006, 1,587 asymptomatic individuals underwent FDG PET/CT as part of a cancer screening program with some other diagnostic tests at the healthcare center of our hospital. After excluding patients with a history of malignant tumor, 1,336 subjects were enrolled. All PET/CT images were visually analyzed. In subjects showing positive findings for PET/CT or other screening tests, further diagnostic tests and pathological confirmation were performed. Of the 1,336 subjects, malignant tumors were found in 16 participants (1.2%, thyroid cancer: 9, lung cancer: 2, stomach cancer: 2, and others: 4). There were 47 cases (3.6%) of positive PET/CT findings—11 cases were true positive (thyroid cancer: 8, lung cancer: 1, renal cancer: 1, and invasive thymoma), and 36 false positive, and five cases were false negative. The overall detection rate of PET/CT was 0.8%, and the sensitivity, specificity, positive-predictive value, and negative-predictive value of PET/CT were 68.8, 97.2, 23.4, and 99.6%, respectively. Fluorodeoxyglucose positron-emission tomography has the potential to detect various kinds of malignant tumors in cancer screening test, and the overall detection rate of PET/CT was 0.8%. FDG PET/CT can be a useful cancer screening modality with the selection of high-risk group and appropriate combination with other screening modalities.
TL;DR: The results demonstrated that the ultra-high spatial resolution SPECT system was feasible for small animal imaging allowing a relatively long data acquisition time.
Abstract: Objective
The aim of this work was to evaluate an ultra-high spatial resolution SPECT system with a semiconductor detector and a high-resolution parallel-hole collimator or a pinhole collimator for small animal imaging.
TL;DR: Although dual-time point PET/CT scan enhances the difference of 18F-FDG uptake between FDG-avid metastatic and benign LNs and improves the differentiation when compared with a single scan, biopsy procedure may be still required for accurate assessment of LN status in patients with NSCLC and possible etiologies showing intensive FDG uptake in benign LN.
Abstract: Objective
To clarify the difference of 18F-FDG uptake kinetics between FDG-avid metastatic lymph nodes (LNs) in patients with non-small-cell lung cancer (NSCLC) and FDG-avid benign LNs associated with various etiologies on dual-time point PET/CT scan, and to determine the optimal parameter for differentiation.
TL;DR: The adverse effect caused by high plasma glucose level was minimum and the FDG uptake of the tumor maintained a sufficiently high level for visual clinical diagnosis in most cases, except in the cases of low FDG-avid tumors or small lesions.
Abstract: Objectives
The purpose of this study was to evaluate the adverse effects of chronic marked hyperglycemia on clinical diagnostic performance of positron emission tomography (PET) using 18F-fuorodeoxyglucose (FDG).
TL;DR: This initial experience with the combined use of 18F-FDG and 68Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors, which merits further evaluation of the utility of the combination.
Abstract: To evaluate the role of combination of 18F-FDG PET-CT scan and 68Ga DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Study design: Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent 18F-FDG PET-CT scan, 68Ga DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild 18F-FDG uptake and high 68Ga DOTA-TOC uptake. Atypical carcinoid had moderate uptake of 18F-FDG and high 68Ga DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of 18F-FDG and no uptake of 68Ga DOTA-TOC. Mucoepidermoid carcinoma showed mild 18F-FDG uptake and no 68Ga DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate 18F-FDG uptake and mild focal 68Ga DOTA-TOC uptake. This initial experience with the combined use of 18F-FDG and 68Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of 18F-FDG PET-CT scan and 68Ga DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.
TL;DR: PET/CT showed poor sensitivity and high specificity in the detection of axillary lymph node metastasis of breast cancer and Diagnostic performance of PET/CT was not superior to that of ultrasonography and contrast-enhanced CT.
Abstract: Purpose
The purpose of this retrospective study was to evaluate the diagnostic performance of positron emission tomography/computed tomography (PET/CT) with fluorine-18–labeled 2-fluoro-2-deoxy-d-glucose (FDG) in comparison with that of ultrasonography and contrast-enhanced computed tomography (CT) in detecting axillary lymph node metastasis in patients with breast cancer.
TL;DR: Myocardial sympathetic nerve and metabolic scintigraphy data that were specific for the Japanese population were generated and found to be different from that of perfusion tracers and can serve as a standard for nuclear cardiology work conducted in Japan.
Abstract: The standard patterns of myocardial radiotracer distribution of 123I-metaiodobenzylguanidine (MIBG) and 123I-β-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) should be defined in a Japanese population. The purpose of this study was to present and provide data on the characteristics of MIBG and BMIPP with respect to myocardial single photon emission computed tomography. The normal database included 123I-MIBG and 123I-BMIPP imaging and a 99mTc-sestamibi/tetrofosmin myocardial perfusion study. The projection images were transferred by digital imaging and communications in medicine (DICOM) format and reconstructed and analyzed with polar maps. The projection data from multiple centers were successfully transferred to a common format for SPECT reconstruction. When the average values were analyzed using a 17-segment model, MIBG uptake in the inferior and apical wall appeared to be slightly lower than anterior uptake (P < 0.05). The inferior and apical uptake of MIBG has a larger standard deviation (10.7 units in males, 12.6 units in females). BMIPP uptakes in the septal wall have higher than that of 99mTc-tracer uptake (P < 0.05). Myocardial sympathetic nerve and metabolic scintigraphy data that were specific for the Japanese population were generated and found to be different from that of perfusion tracers. The normal database can serve as a standard for nuclear cardiology work conducted in Japan.
TL;DR: Accumulation of 18FDG in the stomach suggests a high probability of the presence of inflammatory change in the gastric mucosa forming a background for the development of cancer or malignant lymphoma, and thus requires further endoscopic examinations.
Abstract: To explain the accumulation of 18F-2-deoxy-2-fluoro-glucose (18FDG) on positron emission tomography (PET) in the stomach and differences in its pattern, we focus on the accumulation pattern in association with endoscopic findings of the gastric mucosa and Helicobacter pylori (Hp) infection. Of 599 cases undergoing 18FDG-PET examinations, we retrospectively analyzed the pattern of 18FDG accumulation in the stomach, findings of upper gastrointestinal endoscopy, and Hp infection. The pattern of 18FDG accumulation was classified into three groups: localized accumulation only in the fornix (Group A, 32 patients), diffuse accumulation throughout the entire stomach (Group B, 49 patients), and no accumulation (Group C, 191 patients). Regarding the relation between Hp infection and 18FDG accumulation, Hp infection was positive in 56.3% of Group A, 73.5% of Group B, and 24.1% of Group C, with significant differences (p < 0.001). Regarding the relation between 18FDG accumulation and gastric mucosal inflammation, when Groups A and B were compared with Group C, nearly half of the cases in the former groups had papular redness with a significantly higher frequency of redness and erosion. Three cases found to have malignant tumor were limited to the former groups. One MALT lymphoma case was also found in the same group. Accumulation of 18FDG largely corresponded to mucosal inflammation including superficial gastritis and erosive gastritis, and therefore the main cause of non-specific 18FDG accumulation was considered to be inflammatory mucosa (mainly redness). The accumulation pattern was not associated with atrophic changes of the gastric mucosa or with Hp infection, but with mucosal inflammatory changes, including redness and erosion localized to the fornix. Accumulation of 18FDG in the stomach suggests a high probability of the presence of inflammatory change in the gastric mucosa forming a background for the development of cancer or malignant lymphoma, and thus requires further endoscopic examinations.