SPECT myocardial blood flow quantitation toward clinical use: a comparative study with 13N-Ammonia PET myocardial blood flow quantitation.

OBJECTIVES: The aim of this study was to evaluate the accuracy of myocardial blood flow (MBF) quantitation of 99mTc-Sestamibi (MIBI) single photon emission computed tomography (SPECT) compared with 13N-Ammonia (NH3) position emission tomography (PET) on the same cohorts. BACKGROUND: Recent advances of SPECT technologies have been applied to develop MBF quantitation as a promising tool to diagnose coronary artery disease (CAD) for areas where PET MBF quantitation is not available. However, whether the SPECT approach can achieve the same level of accuracy as the PET approach for clinical use still needs further investigations. METHODS: Twelve healthy volunteers (HVT) and 16 clinical patients with CAD received both MIBI SPECT and NH3 PET flow scans. Dynamic SPECT images acquired with high temporary resolution were fully corrected for physical factors and processed to quantify K1 using the standard compartmental modeling. Human MIBI tracer extraction fraction (EF) was determined by comparing MIBI K1 and NH3 flow on the HVT group and then used to convert flow values from K1 for all subjects. MIBI and NH3 flow values were systematically compared to validate the SPECT approach. RESULTS: The human MIBI EF was determined as [1.0-0.816*exp(-0.267/MBF)]. Global and regional MBF and myocardial flow reserve (MFR) of MIBI SPECT and NH3 PET were highly correlated for all subjects (global R2: MBF = 0.92, MFR = 0.78; regional R2: MBF ≥ 0.88, MFR ≥ 0.71). No significant differences for rest flow, stress flow, and MFR between these two approaches were observed (All p ≥ 0.088). Bland-Altman plots overall revealed small bias between MIBI SPECT and NH3 PET (global: ΔMBF = -0.03Lml/min/g, ΔMFR = 0.07; regional: ΔMBF = -0.07 - 0.06 , ΔMFR = -0.02 - 0.22). CONCLUSIONS: Quantitation with SPECT technologies can be accurate to measure myocardial blood flow as PET quantitation while comprehensive imaging factors of SPECT to derive the variability between these two approaches were fully addressed and corrected.

Pazopanib Sensitivity in a Patient With Breast Cancer and FGFR1 Amplification.

Treatment options for patients with hormone receptor-positive (HR+), HER2-negative (HER2-) breast cancer and resistance to endocrine therapy remain limited. An interesting therapeutic target in these patients is fibroblast growth factor receptor 1 (FGFR1). FGFR1 is amplified in approximately 11% of patients with breast cancer, especially those with HR+ disease. This report presents a patient with metastatic HR+ HER2- breast cancer harboring an FGFR1 amplification who was resistant to endocrine therapy but responded to pazopanib, a multi-tyrosine kinase inhibitor with FGFR-inhibiting activity. Upon pazopanib treatment, the patient's brain lesions nearly disappeared, and she experienced therapeutic changes in the lung and an improvement of liver function. This case suggests that pazopanib may be a promising agent for the treatment of patients with breast cancer and FGFR1 amplifications.

High CEA levels in a case of resected colorectal cancer: delayed diagnosis of metachronous medullary thyroid cancer.

BACKGROUND: Carcinoembryonic antigen (CEA) is one of the most widely used tumor markers, and its value in the surveillance of post-operative colorectal cancer is well established. Fluorodeoxyglucose-positron emission tomography (FDG-PET) has been clinically used in colorectal cancer imaging including preoperative staging, evaluation of therapeutic response, detection of disease recurrence, and investigation of unexplained rising tumor markers. CASE PRESENTATION: We report a case of resected colorectal cancer presented with rising CEA levels in 5 years, and FDG-PET revealed no definitive evidence of recurrence except abnormal focal FDG uptake in the right thyroid lobe. However, fine needle aspiration cytology (FNAC) of the thyroid nodule showed negative for malignancy. Progressively rising CEA levels were noted over the following 5 years, but serial follow-up examinations did not find evidence of recurrence. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) was performed subsequently and again showed focal FDG uptake in the right thyroid lobe. This time, FNAC revealed positive for malignancy, in favor of medullary thyroid carcinoma (MTC). The patient underwent total thyroidectomy and modified radical neck dissection, and MTC with cervical nodal metastasis (pT3N1) was diagnosed. He had cervical lymph nodes recurrence 2 years later, which was resected. CONCLUSIONS: This case reminded us that FDG-PET/CT may detect occult tumors resulting in CEA elevation other than colorectal cancer. Moreover, FNA has a higher false negative rate in detecting MTC than other forms of thyroid cancer. Repeat FNAC for the initial negative cytology result and measure of serum calcitonin for the early MTC detection could be more helpful to avoid the delay in MTC diagnosis.

Utility of FDG PET/CT in Patient with Synchronous Breast and Colon Cancer.

The most common malignancy in women is breast cancer, and the second one is colon cancer. Synchronous breast and colon cancers are rare. Here, we reported a 60-year-old woman with a left breast mass for six months. Biopsy revealed an invasive ductal carcinoma. She underwent 2-[Fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) scan for evaluation of the extent of the disease. FDG PET/CT revealed an advanced left breast cancer with multiple metastases in both regional and distant lymph nodes (in left axilla level I/II, lower paratracheal region, and right lung hilum), bilateral lungs, and axial and proximal appendicular skeletons. An early staged synchronous colon cancer was detected incidentally on FDG PET/CT images. After endoscopic mucosal resection of colon cancer, she received palliative chemotherapy for breast cancer with a marked therapeutic response. The disease status of post-treated breast cancer remained relatively stationary for more than one year. Brain metastasis was noted afterward. Nevertheless, there was no evidence of colon cancer recurrence throughout her breast cancer disease course.

The Fast Growth and Quick Spread of Synchronous Tumors.

A 47-year-old man was diagnosed with left buccal squamous cell carcinoma using FDG PET/CT, by which focal lesions in the left buccal and left neck lymph node were found. Three months after the operation, CT images revealed a left lower lung lesion. Pathology indicated a left lower lung adenocarcinoma. Second FDG PET/CT was performed more than 11 days later, and lesions with intense FDG uptake were found in the left lower lung, metastatic to the lymph nodes, lungs, bones, and liver. The prior FDG PET/CT scan showed negative findings in the lungs. However, lung cancer with multiple metastases appeared 4 months later.

Mycobacterium tuberculosis Invasion of Main Pulmonary Artery.

ABSTRACT: Infectious causes of pulmonary artery invasion are extremely rare. A 71-year-old man had history of progressive dyspnea with abnormal salty taste. Contrast CT showed a filling defect mass in the main pulmonary artery with extraluminal extension to the heart and mediastinum. FDG PET/CT revealed a mass lesion with intense FDG uptake in the main pulmonary artery and peripheral. There were lesions with intense FDG uptake in the middle mediastinum besides the ascending aorta. Malignant tumor was suspected. Later, he received tumor debulking excision. Pathology reports showed necrotizing granulomatous inflammation, positive interferon-gamma release assays, and positive Mycobacterium tuberculosis culture.

The Detection Performance of 18 F-Prostate-Specific Membrane Antigen-1007 PET/CT in Primary Prostate Cancer : A Systemic Review and Meta-analysis.

BACKGROUND: Multiple tools are now available to determine the requirement for a biopsy to diagnose prostate cancer, and PET/CT with radiolabeled prostate-specific membrane antigen (PSMA)-targeting radiotracers has been recommended for detecting primary prostate cancer. Particularly, the radiotracer 18 F-PSMA-1007 was found to be more favorable for primary tumors compared with other PSMA-targeting radiotracers because of its low clearance via the urinary tract and better image resolution. Thus, we performed a systematic review and meta-analysis to more accurately evaluate the detection performance of 18 F-PSMA-1007 PET/CT in primary prostate cancer patients. METHODS: An update on the databases of PubMed/MEDLINE, EMBASE, and Cochrane Library for comprehensive literature search was performed on September 30, 2021. The pooling detection rate was calculated on a per-patient basis. The pooling median of the SUV max was analyzed from the included studies. Furthermore, the positive predictive value of 18 F-PSMA-1007 PET/CT with pathologic lesions was analyzed using the criterion standard. RESULTS: Twelve studies (540 patients total) were included in the meta-analysis. The overall pooling detection rate of 18 F-PSMA-1007 per patient was 94%, and the pooling median of SUV max located at the intraprostate tumor was 16 (range, 3.7-77.7). The positive predictive value of 18 F-PSMA-1007 per lesion with histopathological validation was 0.90, detecting regional lymph node metastasis was 0.94, and detecting localized prostatic tumors was 0.84. CONCLUSIONS: In the current meta-analysis, we revealed the excellent performance of 18 F-PSMA-1007 to detect localized prostatic tumor lesions and regional lymph node metastasis. Moreover, the uptake of localized tumors in primary prostate cancer was nearly liver uptake and may be considered a suspicious malignancy if it was equal to or greater than the liver uptake.

Use of laxative-augmented contrast medium in the evaluation of colorectal foci at FDG PET.

PURPOSE: To compare the diagnostic accuracy of fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in the detection of colon lesions with that of delayed PET/computed tomography (CT) performed after the administration of a laxative-augmented contrast medium. MATERIALS AND METHODS: All patients gave written informed consent according to the guidelines issued by the institutional review board. In a prospective study performed from November 2005 to December 2006, images obtained in 847 patients were reviewed by two physicians in consensus. Colorectal FDG uptake on initial PET images that exceeded background FDG accumulation was graded as minimal, equivocal, or positive. When the initial PET scan revealed a colorectal region of increased uptake, either oral or anal laxative-augmented contrast medium was administered on the basis of the site of colorectal FDG focus and delayed PET/CT was performed. Initial PET findings were reevaluated and revised when necessary. Comparison was performed on a per-patient basis. Findings at histopathologic analysis and clinical follow-up served as the reference standard. The accuracy of PET was compared with that of PET/CT by using the McNemar test. RESULTS: Colorectal FDG foci were seen on initial images in 137 patients. Uptake on the initial images was reported as minimal in 14 patients, equivocal in 68, and positive in 55. With use of a laxative-augmented contrast medium and delayed PET/CT, the proportions of equivocal and positive results decreased by 84% (57 of 68 patients) and 58% (18 of 31 patients), respectively. The accuracy of delayed PET/CT in the depiction of colorectal cancer was greater than that of initial PET (93.4% [128 of 137 patients] vs 71.5% [98 of 137 patients], respectively; P < .01). CONCLUSION: Delayed PET/CT with laxative-augmented contrast medium is more accurate than initial PET alone in the detection of colorectal cancer. This approach has promise as a tool for guiding decisions about how to treat patients with colorectal FDG foci. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101193/-/DC1.

Combined positron emission tomography-computed tomography and tumor markers for detecting recurrent ovarian cancer.

OBJECTIVE: To evaluate the accuracy of integrated FDG-PET/CT and tumor markers for the depiction of recurrent ovarian carcinoma. METHODS: Patients with pathologically proven ovarian cancer, who underwent cytoreductive surgery and 3-6 cycles of adjuvant chemotherapy, were included in this study. They all underwent a thorough physical examination, tumor marker determination, and FDG-PET/CT imaging. The sensitivity, specificity, accuracy, and positive and negative predictive values for the tumor detection with PET/CT versus different tumor markers were performed in relation to the results at histological analysis after second-look surgery or clinical follow-up. RESULTS: A total of 37 patients underwent FDG-PET/CT scans. Among them, 22 patients underwent exploratory laparotomy and 15 had diagnostic laparoscopy. Overall, 24 patients were documented to have ovarian cancer recurrence after second operation. FDG-PET/CT had sensitivity, specificity, accuracy, and positive and negative predictive values of 100, 85, 94, 92, and 100%, respectively. CONCLUSION: Our study has shown that PET/CT is a sensitive tool to assist in the early identification and recurrent ovarian cancer, amenable to secondary cytoreduction.

Changes in Physical Fitness and Body Composition Associated with Physical Exercise in Patients with Myasthenia Gravis: A Longitudinal Prospective Study.

There is a lack of guidelines for physical exercise in patients with myasthenia gravis (MG). A few pilot studies have shown that exercise can be safely applied to patients with MG. However, how physical exercise affects body composition, disease function, and disease severity remains unknown. In this prospective study, we enrolled 34 patients with MG with stable condition and evaluated the disease severity, physical fitness parameters, and body composition (measured using whole-body dual-energy X-ray absorptiometry (DXA)), before and after conducting a 24-week physical exercise regimen of aerobic and resistance strength training. The outcomes were measured by DXA, quantitative MG (QMG) score, quality of life score, handgrip strength and walking speed. During the training regimen, participants were free to decide how many exercise sessions per week and regularly reported their weekly exercise time. The physical exercise program was well tolerated by the participants, the parameters of the QMG score and handgrip strength improved, and participants' body composition did not change significantly. The high exercise group experienced greater deterioration in muscle mass in the arms, but exhibited a greater improvement in forced vital capacity, walking speed, and symptom severity. The group with low QMG scores improved more in terms of physical fitness, including walking speed. These findings indicate that physical exercise is well tolerated by patients with MG, and is accompanied by improved muscular and physical functions. We propose that physical exercise is safe, effective, and appropriate for patients with well-regulated MG.

Assessment of Sarcopenia and Obesity in Patients with Myasthenia Gravis Using Dual-Energy X-ray Absorptiometry: A Cross-Sectional Study.

Sarcopenia and obesity can negatively impact quality of life and cause chronic fragility, and are associated with neuromuscular diseases, including myasthenia gravis (MG). The long-term consequences of body composition changes in chronic MG remain unknown; we therefore evaluated changes in body composition, including sarcopenia, obesity, lean body mass, and the prevalence of sarcopenic obesity in patients. In this cross-sectional study, 35 patients with MG (mean age: 56.1 years) and 175 matched controls were enrolled. Body fat mass and skeletal muscle mass were measured using whole body dual-energy X-ray absorptiometry. Patients with MG exhibited a higher prevalence of obesity and higher android adiposity and total body fat percentage than those of controls. Although the prevalence of sarcopenia and sarcopenic obesity did not increase with age, there was a decrease in arm and android muscle mass in patients with MG compared with controls. Lower muscle mass percentages were correlated with increased age and MG severity, but not with corticosteroid use. Thus, MG is associated with increased risk for obesity and decreased muscle mass with aging, regardless of corticosteroid use. Therefore, accurate diagnosis of body composition changes in MG could facilitate the application of appropriate therapies to promote health, improve quality of life, and prevent fragility.

Dermoid cyst with secretion of CA 19-9 detected by 18F-FDG PET/CT: A case report.

INTRODUCTION: Carbohydrate antigen 19-9 (CA 19-9) is a tumor glycolipid, frequently elevated in the serum of patients due to malignancies from gastrointestinal organs; in particular, the pancreas. This carbohydrate antigen is also expressed in benign diseases. PATIENT CONCERNS: A case of a 27-year-old female who has an unknown origin CA 19-9 elevation for 2 years. DIAGNOSIS: After the left ovarian cystectomy and microscopic examination, the final diagnosis is a dermoid cyst. The dermoid cyst shows increased F-fluorodeoxyglucose (F-FDG) uptake in the F-FDG positron emission tomography (PET)/computed tomography (CT) study. INTERVENTION AND OUTCOMES: The laparoscopic oophorocystectomy was performed. It was observed that the patient's CA 19-9 level returned to normal after the surgery 6 months later. This showed that the dermoid cyst was responsible for the abnormal CA 19-9 level. CONCLUSION: In this case, we can learn that the F-FDG PET/CT scan has potential use in patients with unknown origin of elevation CA 19-9.

A method to measure the extent of myocardial ischemia and steal with SPECT myocardial blood flow quantitation.

OBJECTIVE: We introduced a method to measure the extent of myocardial ischemia and steal with SPECT MBF quantitation. METHODS: Eighty-seven patients who received rest/Dipyridamole-stress 99mTc-Sestamibi (MIBI) dynamic SPECT scans and coronary angiography were included. Dynamic SPECT images were reconstructed with full physical corrections. The one-tissue kinetic model was utilized to quantify K1 and further converted to MBF with required corrections. Rest MBF, stress MBF and myocardial flow reserve (MFR) were converted to a flow status polar map by a flow diagram. Extents of 7 flow statuses were verified their cutoff points for detecting stenoses. The diagnostic performance (DP) was compared to that of MFR. RESULTS: Cutoff point of the extent to detect ≥ 50% stenosis was 3.01% for ischemia-steal status and 20.3% for the combined status of ischemia-steal and moderate. Using these criteria, sensitivity, specificity and accuracy to detect ≥ 50% stenosis were (80%, 75%, 79%) and (86%, 68%, 80%) for ≥ 70% stenosis. The DP was superior to that of MFR < 2.0 criterion (≥ 50%: 70%, 63%, 69%; ≥ 70%: 73%, 61%, 69%) (all p < 0.015). CONCLUSION: SPECT MBF quantitation integrated with the flow diagram can measure the extent of myocardial ischemia and steal which appeared more accurate to detect angiographic stenoses than the single MFR parameter.

F-18 FDG PET in detecting uterine leiomyoma.

PURPOSE: Uterine leiomyoma, benign tumors of the human uterus, are clinically apparent in about 25% of women and the most common solid pelvic tumors. The purpose of this study was to investigate the F-18 2-fluoro-2-deoxy-D-glucose (FDG) uptake in the uterine leiomyoma and assess the correlation between the intensity of FDG uptake in the uterine leiomyomas and menstrual cycle. METHODS: A total of 589 charts of healthy females examined by whole body FDG positron emission tomography (PET) for health screening examination were reviewed retrospectively. Twenty-two of them were suspected gynacecological tumors and referred to the department of gynacecology to ascertain the nature of the causes. Final diagnosis as uterine leiomyomas were made based on uterine sonography, pelvic computed tomography, or pelvic magnetic resonance imaging scans. We defined FDG uptake as Grade I when FDG uptake was less than liver uptake, Grade II when FDG uptake was equal to liver uptake, and Grade III when FDG uptake was greater than liver uptake. The menstrual cycle was recorded on the day of performing FDG PET in premenopausal women. RESULTS: The FDG uptake in the uterine region is Grade I in three of these 22 females (13.65%), Grade II in 16 (72.7%), and Grade III in 3 (13.65%). CONCLUSION: There is no significant correlation between the intensity of FDG uptake in the uterine leiomyomas and menstrual cycle (P=.914).

Utility of 18F-FDG PET/CT uptake patterns in Waldeyer's ring for differentiating benign from malignant lesions in lateral pharyngeal recess of nasopharynx.

UNLABELLED: Focally increased (18)F-FDG uptake in the lateral pharyngeal recess (LPR) of the nasopharynx due to a benign or malignant lesion is not an uncommon finding on PET images. The aim of this study was to evaluate whether, on PET/CT images, (18)F-FDG uptake occurs with characteristic patterns and intensities in various regions of Waldeyer's ring that can improve our ability to differentiate benign from malignant lesions. METHODS: Data generated from the (18)F-FDG PET/CT images of 1,628 subjects in our cancer-screening program were analyzed. Increased uptake in the LPR was observed in 80 subjects (4.9%) presenting with benign lesions, including 53 subjects without and 27 subjects with symptoms of upper airway discomfort. In addition, 30 healthy controls and 21 patients with newly diagnosed nasopharyngeal carcinoma were recruited for this study. Visual uptake, measurements of the lesions' standardized uptake value (SUV), and any abnormalities on PET/CT were evaluated. The receiver-operating-characteristic curve and area under the curve were applied to evaluate the discriminating power. RESULTS: Increased (18)F-FDG uptake (SUV, mean +/- SD) was found in the LPR, with a statistically significant (P < 0.001) difference between benign lesions (3.0 +/- 1.16) and malignant lesions (7.03 +/- 3.83). However, associated increased uptake exclusively in the palatine tonsil, lingual tonsil, and submandibular gland was found in both asymptomatic and symptomatic subjects. The ratio of LPR uptake to palatine tonsil uptake (N/P ratio) in benign lesions (0.81 +/- 0.37) was significantly (P < 0.001) lower than that in malignant lesions (2.30 +/- 1.62). Higher incidences of asymmetric (18)F-FDG LPR uptake, cervical lymph node uptake, and asymmetric wall thickening of the LPR on CT were observed in patients with nasopharyngeal carcinoma. When an SUV of less than 3.9 and an N/P ratio of less than 1.5 were used as cutoff points in subjects showing the combination of symmetric uptake in the LPR and normal or symmetric wall thickening, and detectable lymph node uptake, the area under the curve for benign lesions on PET/CT was 0.932 +/- 0.042 (95% confidence interval, 0.86-0.98), with a sensitivity of 90.4% and a specificity of 93.8%. CONCLUSION: The intensity and patterns of (18)F-FDG uptake in various regions of Waldeyer's ring along with CT scan findings provide a feasible modality to differentiate benign from malignant nasopharyngeal lesions.

Correlation between the intensity of breast FDG uptake and menstrual cycle.

RATIONALE AND OBJECTIVES: [18F]fluorodeoxyglucose positron emission tomography (F-18 FDG PET), a functional imaging modality has opened a new field in clinical imaging that informs about glucose metabolism of tissues. However, increased FDG uptake is not limited to malignant tissues alone. We hypothesize that the intensity of physical FDG uptake in the normal breast tissues would affect the detect ability of breast cancer; therefore, good knowledge of physical FDG uptake in the healthy population is important for the correct interpretation of FDG PET images of pathologic processes. The study aimed to evaluate the relationship between intensity of FDG uptake in the normal breast tissues and menstrual cycle. MATERIALS AND METHODS: A total of 1,108 charts of healthy females, referred from the department of family medicine of China Medical University Hospital, examined by whole-body FDG PET for health screening examination between June 2002 and June 2006 were reviewed retrospectively and included for analyzing. A total of 524 premenopausal females with regular menstrual cycles over the previous 6 months (length 26-30 days) and 584 menopausal females without current use of exogenous hormones were included in this study. The menstrual cycle was recorded on the day of performing FDG PET in premenopausal women. The breast tissues are diagnosed as normal either by mammary sonography or by mammography. We defined FDG uptake was Grade I when FDG uptake was equal to the pulmonary uptake, Grade II when FDG uptake between pulmonary and liver uptake, and Grade III when FDG uptake equal to or greater than liver uptake. RESULTS: The FDG uptake in the breast regions shows Grade I in 500 women (45.1%), Grade II in 281 (25.4%) and Grade III in 327 (29.5%). Among the Grade I uptake group, 388 are menopausal, 1 is in flow phase, and 111 are in proliferative phase. Among the Grade II uptake group, 196 are menopausal, 23 are in flow phase, 9 are in proliferative phase, 43 are in the ovulatory phase, and 10 are in the secretory phase. Among Grade III uptake group, 97 are in flow phase, 108 are in the ovulatory phase, and 122 in the secretory phase. The study shows significant correlation between the intensity FDG uptake in the normal breast tissues and menstrual cycle (P < .001). CONCLUSIONS: The physical FDG uptake in the normal breast tissues is generally homogeneous. There is no Grade III FDG uptake in the normal breast tissues in menopause women without using exogenous hormones or in proliferative phase women. In addition, there is no Grade I FDG uptake in the normal breast tissues in the ovulatory phase or secretory phase women.

The significance of FDG uptake in bilateral thyroid glands.

AIM: To evaluate the significance of bilateral fluorodeoxyglucose (FDG) uptake in the thyroid glands. METHODS: Bilateral thyroid FDG uptake, defined as visualization of thyroid glands, was found in 66 (3.4%) of 1925 subjects who underwent our FDG PET cancer-screening program. Additionally, 16 of the 41 patients with Graves' disease and hyperthyroidism (GD(H)) and six of the 20 subjects with Graves' disease and euthyroidism (GD(E)), who had FDG uptake in thyroid glands, were enrolled in this study. RESULTS: Among the 66 subjects, 22 were normal variant, 39 subjects had chronic thyroiditis (35 subjects presented with diffuse goitre and four with multinodular goitre), and five subjects had multinodular goitre (MNG) without chronic thyroiditis. Fourteen of 22 (63.6%) of the subjects with the normal variant had a visual uptake intensity less than that of the liver, while 30 of 39 (76.9%) of the subjects with chronic thyroiditis and 14 of 22 (63.6%) of the subjects with Graves' disease had visual uptake intensity greater than or equal to liver uptake. Two of the five subjects with MNG with focally intense uptake were proven to have thyroid carcinoma. Bilateral loser uptake in thyroids associated with thymus and symmetrical skeletal muscle uptake were found in GD(H). The standard uptake value (SUV) (mean+/-SD) in subjects with chronic thyroiditis (2.76+/-1.24) were higher, while those with GD(H) (1.59+/-0.36) were lower than that of the normal variant (1.99+/-0.63). Subjects with hypothyroidism (3.04+/-1.39) had higher SUV levels than those subjects with euthyroidism (2.44+/-1.11). In addition, patients with GD(H) had lower levels than those with GD(E) (2.0+/-0.38). CONCLUSION: (1) Bilateral thyroidal uptake of FDG can be found in normal variants and subjects with various thyroid disorders, showing varieties of uptake patterns. (2) Diffuse intense uptake and higher SUV levels are a clue to a diagnosis of chronic thyroiditis, especially for those with hypothyroidism. (3) Focally intense uptake suggests the possibility of a thyroid carcinoma. (4) Sparse uptake associated with the thymus and symmetrical skeletal muscle uptake and lower SUV level raise the possibility of Graves' disease with hyperthyroidism.

Diagnostic trinity: Graves' disease on F-18 FDG PET.

A 31-year-old man underwent a whole-body F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) scan for cancer screening. There was no history of diabetes, thyroid disease, or noticeable exercise before imaging. The results demonstrated diffusely increased uptake of F-18 FDG in the thyroid and thymus. In addition, there was symmetrically increased uptake of F-18 FDG in skeletal muscles, especially in the psoas and limb muscles. The concurrent appearance of these characteristics led to a diagnosis of Graves' disease.

Noninvasive Nuclear SPECT Myocardial Blood Flow Quantitation to Guide Management for Coronary Artery Disease.

Recently, myocardial blood flow quantitation with dynamic SPECT has been validated to enhance the detection of multivessel coronary artery disease (CAD) and conclude equivocal SPECT myocardial perfusion study. This advance opened an important clinical application to utilize the tool in guiding CAD management for area where myocardial perfusion tracers for PET are unavailable or unaffordable. We present a clinical patient with ongoing recursive angina who underwent multiple nuclear stress tests for a sequence of CAD evaluation in 26 months and demonstrated that SPECT myocardial blood flow quantitation properly guided CAD management to warrant patient outcome.

Clinical usefulness of fused PET/CT compared with PET alone or CT alone in nasopharyngeal carcinoma patients.

UNLABELLED: The diagnostic accuracy of fused positron emission tomography/computed tomography (PET/CT) was compared with CT alone and PET alone in the staging and re-staging of nasopharyngeal carcinoma (NPC) patients. PATIENTS AND METHODS: Eighty-six fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG) PET/CT studies were retrospectively performed in 70 patients with NPC, 20 patients for primary tumor staging and 50 patients for re-staging after treatment. Each lesion was analyzed visually and assigned a score on a 5-point scale. Each study was interpreted in 3 ways: PET images were evaluated in the absence of CT data, CT images in the absence of PET data and fused PET/CT images. The results of these images were correlated with histological findings, as well as long-term radiological and clinical follow-up (the shortest follow-up period after imaging was 6 months). PET, CT and PET/CT accuracy were compared by a McNemar test. RESULTS: Fused PET/CT correctly characterized the tumor-node-metastasis system stage in 82 out of 86 studies (95.4%; 95% CI: 90.9% to 99.9%). PET alone and CT alone were found to be accurate in 71 out of 86 studies (82.6%; 95% CI: 74.5% to 90.6%) and 63 out of 86 studies (73.3%; 95% CI: 63.9% to 82.6%), respectively. Furthermore, the differences between PET/CT and either PET alone or CT alone were statistically significant (p<0.05). Overall, the study-based analysis of PET/CT for staging NPC demonstrated 48 true-positive, 2 false-negative, 34 true-negative and 2 false-positive studies. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of FDG-PET/CT studies for staging NPC were 96%, 94.4%, 95.4%, 96% and 94.4%, respectively. CONCLUSION: PET/CT is more accurate than PET alone or CT alone for the depiction of NPC. Fused PET/CT is a valuable imaging tool in patients for staging diagnosis of NPC.