Incidence rate and factors associated with the development of secondary cancers after radioiodine therapy in differentiated thyroid cancer: a multicenter retrospective study.

PURPOSE: The objective of this study was to estimate the incidence of secondary cancers and the factors associated with their development among patients who underwent radioiodine therapy (RIT) with differentiated thyroid cancer. METHODS: We retrospectively collected medical records for patients who underwent first RIT between January 1, 2000, and December 31, 2005, from seven tertiary hospitals in South Korea after total thyroidectomy for differentiated thyroid cancer. Cancer incidence and calculated standardized rate ratio were compared with Korean cancer incidence data. The association between the development of secondary cancers and various parameters was analyzed by Cox-proportional hazard regression. RESULTS: A total of 3106 patients were included in this study. Mean age at the time of diagnosis of thyroid cancer was 45.7 ± 13.3 years old, and 2669 (85.9%) patients were female. The follow-up period was 11.9 ± 4.6 (range, 1.2-19.6) years. A total of 183 secondary cancers, which included 162 solid and 21 hematologic cancers, occurred in 173 patients (5.6%). There was no significant difference between solid cancer incidence in our study population who underwent RIT and the overall Korean population, but the incidence of hematologic cancers and total cancer in our study was significantly higher compared with that of the Korean population. A multivariate analysis identified independent prognostic factors for the development of secondary cancer including age at 1st RIT, male, and total cumulative dose over 200 mCi. CONCLUSION: We need to assess the risk benefit for patients who receive over 200 mCi of a total cumulative dose.

Measurement of SUVs-maximum for normal region using VOI in PET/MRI and PET/CT.

The purpose of this research is to establish an overall data set associated with the VOI (Volume of Interest), which is available for simultaneous assessment of PET/MRI and PET/CT regardless of the use of contrast media. The participants as objects of this investigation are 26 healthy examinees in Korea, SUV (standardized-uptake-value)s-maximum evaluation for whole-body F-18 FDG (fluorodeoxyglucose) PET/MRI image using VOI of normal region has exhibited very significant difference to that for whole-body F-18 FDG PET/CT image (significant probability value (P) < 0.0001). However, there appeared high correlation between them in view of statistics (R-square (R) > 0.8). It is shown that one needs to decide SUVs-maximum for PET/MRI with the reduction of 25.0~26.4% from their evaluated value and needs to decide with the reduction of 28.8~29.4% in the same situation but with the use of contrast media. The use of SUVLBM-maximum (SUVLean Body Mass-maximum) is very advantageous in reading overall image of PET/CT and PET/MRI to medical doctors and researchers, if we consider its convenience and efficiency. We expect that this research enhances the level of the early stage accurate diagnosis with whole-body images of PET/MRI and PET/CT.

Very different external radiation doses in patients undergoing PET/CT or PET/MRI scans and factors affecting them.

Our aim was to determine the external radiation dose rates of patients undergoing positron emission tomography/computed tomography (PET/CT) and PET/magnetic resonance imaging (MRI) examinations, and to assess the factors affecting these doses. The external radiation dose rates (ERDR) from (18)F-FDG were measured using the Geiger-Müller tube at a distance of 10, 50, and 100cm from the patients' skin surface from various body regions. Results showed that at 10cm from the body surface for PET/CT examinations, the ERDR immediately after (18)F-FDG i.v. injection at time points 1 and 4 was 522.19±189.59µSvh(-1) and 256.36±74.94µSvh(-1) , respectively. At 10cm from the body surface for PET/MRI examinations, the ERDR at time points 1 and 4 were 258.76±92.09µSvh(-1) and 105.63±27.48µSvh(-1), respectively, always with a precipitous decrease over time. The (18)F-FDG dose was on average 1.93-fold higher and the ERDR was higher approximately 2.01 to 2.42-fold in PET/CT examinations than in PET/MRI examinations. In both PET/CT and PET/MRI patients, the ERDR was significantly higher with lower body weight, shorter stature, and fewer urinations etc. In conclusion, based on our results, the ERDR to patients from PET/CT scans at a distance of 10cm was twice as high than from the PET/MRI. Furthermore, to decrease ERDR to the patients, the dose injected should be adjusted to body weight and height. Factors like post injection fluid intake and urine bladder emptying, decrease ERDR. Other persons should keep a safe distance from the injected patient.

Initial experience of integrated PET/MR mammography in patients with invasive ductal carcinoma.

The purpose of this study was to evaluate the feasibility of integrated fluorine-18-fluorodeoxyglucose positron emission tomography/magnetic resonance ((18)F-FDG PET/MR) mammography in invasive ductal carcinoma (IDC) patients. From August 2012 to March 2013, we enrolled 42 consecutive breast cancer patients who received whole- body PET/MR and subsequent PET/MR mammography by an integrated PET/MR scanner and were scheduled for surgery within 2 weeks after the of scan. On the whole body PET/MR, 2-point Dixon VIBE, coronal T1w image, axial T2w image, and post-contrast T1 sequences were acquired with simultaneous PET acquisition. For PET/MR mammography, T1w, T2w, and dynamic contrast-enhancement (DCE) sequences were acquired using a breast coil during simultaneous PET acquisition. We compared the detectability of the lesions between whole-body PET/MR and PET/MR mammography. Forty-eight IDC (1.89±1.19cm of width) were diagnosed in 42 women. Lesion conspicuity in (18)F-FDG PET was equivalent between whole-body PET/MR and PET/MR mammography; both PET/MR images showed 38 hypermetabolic masses. In the analysis of 10 IDC with <1.0cm wide lesions, only 1 IDC showed (18)F-FDG uptake, and 4 IDC were noted on whole-body PET/MR; however, all 10 IDC showed a depictable mass on PET/MR mammography. In the analysis of 38 IDC >1.0cm wide, 37 IDC showed (18)F-FDG uptake, and 38 IDC were detected on both whole-body PET/MR and PET/MR mammography. The overall sensitivity was 79.2% (38/48) on PET, 87.5% (42/48) on whole-body PET/MR, and 100% on PET/MR mammography. The SUV between whole-body PET/MR and PET/MR mammography showed strong and highly significant correlation (r=0.987, P<0.001). In conclusion, our results, although in a limited number of cases show that integrated PET/MR mammography is feasible and has the advantage of combining high-resolution breast images with metabolic images. Furthermore, PET/MR mammography could provide an accurate diagnosis in case of IDC that are less than 1cm in size.

Incidental pituitary uptake on whole-body 18F-FDG PET/CT: a multicentre study.

PURPOSE: The purpose of this study was to determine the incidence of incidental pituitary uptake on whole-body 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and to investigate its clinical significance. METHODS: The files of 40,967 patients who underwent whole-body FDG PET/CT were retrospectively reviewed. Quantification of pituitary metabolic activity was obtained by using the maximum standardized uptake value (SUVmax). Hormone assays and pituitary MRIs were performed to assess pituitary lesions. RESULTS: Focally increased pituitary FDG uptake on PET/CT was found in 30 of 40,967 patients, accounting for an incidence of 0.073%. The mean SUVmax of 30 patients was 8.9±6.6 (range: 3.2-32.6). Histological diagnosis was obtained in three patients and included two growth hormone-secreting adenomas and one non-functioning adenoma. Hormone assays were performed on serum samples from 11 patients, 2 of whom were shown to have hypersecretion of pituitary hormone. MRI was performed on 19 patients. Abnormal MRI findings suggesting a pituitary mass were found in 18 of 19 cases (94.7%). The mean SUV(max) calculated without correction for partial volume effect for macroadenomas was significantly higher than the SUVmax for microadenomas (11.5±8.4 vs 4.8±1.3; p<0.05). There were no cases diagnosed with metastasis to the pituitary gland during clinical follow-up. CONCLUSION: Incidental pituitary FDG uptake was a very rare finding. Cases with incidental pituitary FDG uptake were diagnosed primarily with clinically non-functioning adenomas, and there were also a few functioning adenomas. Further evaluations, including hormone assays and pituitary MRI, are warranted when pituitary uptake is found on FDG PET/CT.

Assessment of Therapeutic Response in Pyogenic Vertebral Osteomyelitis Using 18F-FDG-PET/MRI.

PURPOSE: There is still no definite method to determine therapeutic response in pyogenic vertebral osteomyelitis (PVO). We analyzed the value of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for assessing therapeutic response in PVO. METHODS: This retrospective study included 53 patients (32 men and 21 women) with lumbar PVO. The results of clinical assessments for therapeutic response were divided into "Cured" (group C) and "Non-cured" (group NC). The differences in clinical and radiological features of PVO lesions between the two groups were analyzed using clinical data and simultaneous FDG-PET/magnetic resonance imaging (MRI) obtained at each clinical assessment. RESULTS: Clinical assessments and FDG-PET/MRIs were performed at 41.89 ± 16.08 (21-91) days of parenteral antibiotic therapy. There were 39 patients in group C and 14 in group NC. Diagnostic accuracies (DAs) of FDG uptake intensity-based interpretation and C-reactive protein (CRP) for residual PVO were as follows (p < 0.01): 84.9% of the maximum standardized uptake value of PVO lesion (PvoSUVmax), 86.8% of ΔPvoSUVmax-NmlSUVmax (SUVmax of normal vertebra), 86.8% of ΔPvoSUVmax-NmlSUVmean (SUVmean of normal vertebra), and 71.7% of CRP. DAs were better (92.5-94.3%) when applying FDG uptake intensity-based interpretation and CRP together. Under the FDG uptake distribution-based interpretation, FDG uptake was significantly limited to intervertebral structures in group C (p = 0.026). CONCLUSION: The interpretations of intensity and distribution of FDG uptake on FDG-PET are useful for detecting residual PVO in the assessment of therapeutic response of PVO. The combination of FDG-PET and CRP is expected to increase DA for detecting residual PVO.

The clinical efficacy of (18)F-FDG-PET/CT in benign and malignant musculoskeletal tumors.

OBJECTIVE: Most of the current clinical data on the role of 2-[(18)F]fluoro-2-deoxy-D -glucose positron emission tomography ((18)F-FDG-PET) in musculoskeletal tumors come from patients studied with PET and less frequently with hardware fusion PET/computed tomography (CT). And the number of cases in each report is too small to clarify the exact clinical efficacy of PET or PET/CT. This prompted us to analyze our experience with (18)F-FDG-PET/CT in a relatively large group of patients with musculoskeletal tumors. METHODS: (18)F-FDG-PET/CT was performed on 91 patients from May 2004 to June 2007. The final diagnosis was obtained from surgical biopsy in 83 patients (91%) and clinical follow-up in 8 (9%). We analyzed the characteristics and amount of (18)F-FDG uptake in soft tissue and bone tumors, and investigated the ability of (18)F-FDG-PET/CT to differentiate malignant from benign tumors. The cutoff maximum standardized uptake value (SUV(max)) was calculated using the receiver-operation characteristic curve method. Sensitivity, specificity, and diagnostic accuracy were calculated with cutoff SUV(max) and the final diagnosis. Unpaired t test was used for the statistical analysis. RESULTS: Final diagnosis revealed 19 benign soft tissue tumors (mean SUV(max) 4.7), 27 benign bone tumors (5.1), 25 malignant soft tissue tumors (8.8), and 20 malignant bone tumors (10.8). There was a significant difference in SUV(max) between benign and malignant musculoskeletal tumors in total (P < 0.002), soft tissue tumors (P < 0.05), and bone tumors (P < 0.02). Sensitivity, specificity, and diagnostic accuracy were 80%, 65.2%, and 73% in total with cutoff SUV(max) 3.8, 80%, 68.4%, and 75% in the soft tissue tumors with cutoff SUV(max) 3.8, and 80%, 63%, and 70% in the bone tumors with cutoff SUV(max) 3.7. CONCLUSIONS: (18)F-FDG-PET/CT reliably differentiated malignant soft tissue and bone tumors from benign ones, although there were many false-positive and false negative lesions. Further studies with all kinds of musculoskeletal tumors in large numbers are needed to improve the diagnostic accuracy of (18)F-FDG-PET/CT.

Clinical characteristics of ectopic thyroid in Korea.

BACKGROUND: Ectopic thyroid is a rare entity and can occur at any location in the midline position. A role for the ectopic thyroid in the pathogenesis of hypothyroidism and nongoitrous cretinism has been emphasized. OBJECTIVE: To assess the clinical characteristics of an ectopic thyroid by analyzing 49 cases reported in Korea. DESIGN: This study was a retrospective review of 19 cases who were diagnosed by thyroid scan at our institutions together with 30 cases reported in the Korean medical literature, found using KoreaMed. MAIN OUTCOMES: Most cases of ectopic thyroid were diagnosed in patients aged between 1 and 29 years; it was more common in females (43 patients). A lingual thyroid was found in 23 patients, a sublingual thyroid in 17 patients, combined type in 7 patients, a prelaryngeal thyroid in 1 patient, and an intratracheal thyroid in 1 patient. Only four cases had the thyroid gland in the normal position. The chief complaints at presentation were palpable mass in 20 patients, growth retardation in 10 patients, and a lump sensation in the throat in 6 patients. Twenty-six of 42 patients (61.9%) had hypothyroidism, and 16 patients (38.1%) had euthyroidism. As for the treatment modalities, 18 of 26 patients with hypothyroidism and 4 of 16 patients with normal thyroid function received thyroid hormone medication; 3 of 26 patients with hypothyroidism and 8 of 16 patients with euthyroidism underwent resection of the ectopic thyroid. CONCLUSION: Our study suggests that radionuclide thyroid scanning and function testing may be useful not only for the diagnosis of an ectopic thyroid but also before deciding on the therapeutic modality; patients should be followed up to detect changes in thyroid function and malignant transformation.

A case of silent giant cell arteritis involving the entire aorta, carotid artery and brachial artery screened by integrated PET/CT.

We report a case of giant cell arteritis involving the aorta and several large arteries identified by integrated positron emission tomography (PET)/computed tomography (CT) obtained in a patient with a high erythrocyte sedimentation rate (ESR). A 63-year-old man with anemia and a high ESR noted on a regular medical examination was transferred to our department. The patient complained of only a low-grade general weakness for several months; there were no specific symptoms or signs. A PET was recommended. The image showed strong (18)F-fluorodeoxyglucose ((18)F-FDG) uptake at the ascending aorta, aortic arch, descending aorta, thoraco-lumbar aorta, brachial artery, and the carotid artery wall, bilaterally. Suspicious for large-vessel vasculitis, a temporal artery biopsy was performed, which confirmed giant cell arteritis. After treatment with prednisolone, the high ESR and anemia resolved, and (18)F-FDG uptake decreased on follow-up integrated PET/CT.

Potential Clinical Applications of 18F-Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Mammography in Breast Cancer.

The whole-body positron emission tomography (PET)/magnetic resonance (MR) scan is a cutting edge technology providing comprehensive structural information from MR imaging and functional features from PET in a single session. Recent research findings and clinical experience have shown that 18F-fluorodeoxyglucose (FDG) whole-body PET/MR imaging has a diagnostic performance comparable with or superior to that of PET/CT in the field of oncology, including for breast cancer. In particular, FDG PET/MR mammography in the prone position with the breast hanging in a pendant manner can provide more comprehensive information about the metabolism, anatomy, and functional features of a breast lesion than a whole-body PET/MR scan. This article reports on current state-of-the-art PET/MR mammography in patients with breast cancer and the prospects for potential application in the future.

Quantitative assessment of simultaneous F-18 FDG PET/MRI in patients with various types of hepatic tumors: Correlation between glucose metabolism and apparent diffusion coefficient.

PURPOSE: Metabolism and water diffusion may have a relationship or an effect on each other in the same tumor. Knowledge of their relationship could expand the understanding of tumor biology and serve the field of oncologic imaging. This study aimed to evaluate the relationship between metabolism and water diffusivity in hepatic tumors using a simultaneous positron emission tomography/magnetic resonance imaging (PET/MRI) system with F-18 fluorodeoxyglucose (FDG) and to reveal the metabolic and diffusional characteristics of each type of hepatic tumor. METHODS: Forty-one patients (mean age 63 ± 13 years, 31 male) with hepatic tumors (18 hepatocellular carcinoma [HCC], six cholangiocarcinoma [CCC], 10 metastatic tumors, one neuroendocrine malignancy, and six benign lesions) underwent FDG PET/MRI before treatment. Maximum standard uptake (SUVmax) values from FDG PET and the apparent diffusion coefficient (ADC) from the diffusion-weighted images were obtained for the tumor and their relationships were examined. We also investigated the difference in SUVmax and ADC for each type of tumor. RESULTS: SUVmax showed a negative correlation with ADC (r = -0.404, p = 0.009). The median of SUVmax was 3.22 in HCC, 6.99 in CCC, 6.30 in metastatic tumors, and 1.82 in benign lesions. The median of ADC was 1.039 × 10-3 mm/s2 in HCC, 1.148 × 10-3 mm/s2 in CCC, 0.876 × 10-3 mm/s2 in metastatic tumors, and 1.323 × 10-3 mm/s2 in benign lesions. SUVmax was higher in metastatic tumors than in benign lesions (p = 0.023). Metastatic tumors had a lower ADC than CCC (p = 0.039) and benign lesions (p = 0.004). HCC had a lower ADC than benign lesions, with a suggestive trend (p = 0.06). CONCLUSION: Our results indicate that SUVmax is negatively correlated with ADC in hepatic tumors, and each group of tumors has different metabolic and water diffusivity characteristics. Evaluation of hepatic tumors by PET/MRI could be helpful in understanding tumor characteristics.

Clinicopathological analysis and risk factors of advanced colorectal neoplasms incidentally detected by 18F-FDG PET-CT.

BACKGROUND: As the clinical use of fluorine-18-fluorodeoxyglucose PET-computed tomography (F-FDG PET-CT) has increased, the incidental finding of F-FDG uptake with subsequent diagnosis of advanced neoplasm at colorectum has increased. The aim of this study is to analyze the characteristics and risk factors of advanced colorectal neoplasm incidentally detected by F-FDG PET-CT. PATIENTS AND METHODS: Patients who underwent colonoscopy because of an incidental finding of F-FDG uptake at the colorectum from January 2006 to January 2015 at Yeungnam University Hospital were reviewed retrospectively. Advanced neoplasm was defined as adenoma of at least 10 mm, adenoma with serrated or villous component, high-grade dysplasia, and adenocarcinoma. RESULTS: Of the 19 798 candidates, 180 patients with incidental colorectal F-FDG uptake were included in this study. The indications of PET-CT were metastasis work-up, health screening, and others. The male to female ratio was 1.6 : 1 and the mean age was 62.7±11.4 years. A total of 156 lesions were detected in the colorectum and 86 (47.8%) were diagnosed as advanced neoplasms. Of the 86 patients with advanced neoplasms, 34 (39.5%) underwent an operation, 34 (39.5%) underwent endoscopic resection, and 18 (20.9%) underwent chemotherapy or conservative treatments. In univariate analysis, age of 62.5 years or older, carcinoembryonic antigen (CEA) of at least 3.4 ng/ml, maximum standardized uptake value (SUVmax) of at least 8.0, hypertension, F-FDG uptake on the rectosigmoid, and PET-CT for metastasis work-up showed a significant association with advanced neoplasm. In multivariate analysis, CEA (P=0.028), SUVmax (P<0.001) and an indication of PET-CT for metastasis work-up (P=0.008) were independent predictors of advanced neoplasm. CONCLUSION: Colonoscopy should be recommended in case of F-FDG uptake at the colorectum, particularly in patients with CEA of at least 3.4 ng/ml, SUVmax of at least 8.0, or metastasis work-up of malignancy.

Clinical outcomes of low-dose and high-dose postoperative radioiodine therapy in patients with intermediate-risk differentiated thyroid cancer.

PURPOSE: Recent studies have suggested that a low dose (LD) of radioiodine (RAI) is sufficient to treat differentiated thyroid cancer (DTC) even in patients with intermediate risk. However, these studies evaluated the efficacy of RAI therapy, irrespective of the results of the whole-body scan (WBS). The aim of the present study was to evaluate the response to LD and high-dose (HD) RAI therapy using two different criteria (with and without WBS results) and the reclassification system according to the revised 2015 guidelines of the American Thyroid Association in Korean intermediate-risk DTC patients. In addition, we evaluated the long-term clinical outcomes of treatment with LD and HD RAI. MATERIALS AND METHODS: In total, 204 intermediate-risk DTC patients who underwent postoperative RAI therapy at two tertiary referral hospitals from 2003 to 2004 were enrolled in the present retrospective study. One hundred and twenty-four patients were treated with 3.7 and 5.55 GBq (HD) of RAI in one center and 80 patients were treated with 1.11 GBq (LD) in the other center. The success rate of RAI therapy was assessed with or without the inclusion of WBS results in the analysis. In addition, the response to therapy during the first 2 years of follow-up after the initial RAI therapy was categorized according to the reclassification system of 2015 American Thyroid Association guidelines as excellent response, indeterminate response, biochemical incomplete response, or structural incomplete response. Recurrence was defined as a newly detected cytologically or pathologically confirmed lesion. RESULTS: There were no significant differences between the success rates of the HD and LD groups irrespective of the inclusion of WBS results in the analysis (with WBS: 54.84 vs. 45.0%, P=0.23; without WBS: 60.48 vs. 62.5%, P=0.77). The response to HD and LD RAI therapy was excellent in 54.84 and 45.0% of the patients, respectively; indeterminate in 34.68 and 30.0% of the patients, respectively; biochemical incomplete in 4.03 and 13.75% of the patients, respectively; and structural incomplete in 6.45% and in 11.25% of the patients, respectively (P=0.04). In particular, the biochemical or structural incomplete response rate was lower in patients treated with HD than in patients treated with LD (HD, 10.48%; LD, 25.0%, P=0.01). At the last follow-up (HD, median 11 years; LD, median 10 years), patients who achieved an excellent response showed no evidence of disease. After the initial RAI therapy, eight patients in the HD group and 18 patients in the LD group who achieved either indeterminate response or biochemical incomplete response received additional RAI therapy. Seven patients (indeterminate response in five patients; biochemical incomplete response in two patients) in the HD group and seven patients (indeterminate response in five patients; biochemical incomplete response in two patients) in the LD group showed recurrences. CONCLUSION: LD RAI therapy after thyroidectomy appears to be insufficient in Korean DTC patients with intermediate risk. The patients in the LD group predominantly showed biochemical or structural incomplete response to initial RAI therapy and additional RAI therapy was required.

Prognostic value of preoperative 18F-FDG PET/CT in papillary thyroid cancer patients with a high metastatic lymph node ratio: a multicenter retrospective cohort study.

OBJECTIVE: Metastatic lymph node ratio (MLNR) is a known significant predictor of disease-free survival in differentiated thyroid cancer. The authors investigated the ability of preoperative fluorine-18 fluorodeoxyglucose (F-FDG) PET/CT to predict recurrence after surgery with radioactive iodine therapy considering MLNR. PATIENTS AND METHODS: A total of 274 patients who underwent preoperative PET/CT and surgery with radioactive iodine therapy were enrolled. The tumor-to-liver uptake ratio on PET/CT was calculated by dividing the maximum standardized uptake value of a primary lesion by the mean standardized uptake value of the normal liver. High F-FDG uptake was defined as tumor-to-liver uptake ratio more than the median cutoff value (2.1). MLNR was calculated by dividing the number of metastatic lymph nodes (LNs) by the number of cervical LNs removed. A high MLNR was also defined as one more than a threshold value (0.4), identified by plotting Kaplan-Meier survival curves and comparing them using the log-rank test. The prognostic significances of clinicopathologic variables were analyzed. RESULTS: Fifteen (5.5%) patients developed recurrence in the thyroid bed or in cervical LNs. Cox regression analysis showed that a high MLNR was significantly associated with a worse disease-free survival (odds ratio 6.95; 95% confidence interval: 2.36-20.47; P<0.001). A subgroup analysis of 70 patients with a high MLNR showed that only high F-FDG uptake was significantly associated with a worse disease-free survival (odds ratio 5.77; 95% confidence interval: 1.22-27.16; P=0.027). CONCLUSION: High F-FDG uptake of primary lesion on preoperative PET/CT has selective prognostic value according to the extent of metastatic LNs (MLNR>0.4).

Direct comparison of adenosine and adenosine 5'-triphosphate as pharmacologic stress agents in conjunction with Tl-201 SPECT: Hemodynamic response, myocardial tracer uptake, and size of perfusion defects in the same subjects.

BACKGROUND: Adenosine 5'-triphosphate (ATP), a potent and inexpensive coronary vasodilator, was introduced as a pharmacologic stress agent for thallium 201 single photon emission computed tomography (SPECT). However, there has been no direct comparison of ATP and adenosine as myocardial stressors in the same subjects. METHODS AND RESULTS: Thirty-six patients underwent consecutive Tl-201 SPECT imaging with adenosine and ATP in a randomly assigned order. There were no changes in clinical status and no invasive procedures were performed between the two tests. The hemodynamic response and side effects were monitored, and myocardial tracer uptake was assessed by use of a visual grading system and quantitative analysis via a CEqual map. The hemodynamic changes and adverse effects did not differ significantly between the two groups. There were no changes in the detection of any perfusion defect on a per-subject basis, except in one. The exact agreement rate for the visual grading of the myocardial tracer uptake was 84.8%. However, the average extent of the perfusion defect and the severity score were higher with adenosine. CONCLUSION: The hemodynamic changes and the degree of myocardial uptake were similar between the adenosine and ATP infusion. However, quantitative analysis by use of a CEqual map revealed smaller perfusion defects and lower severity scores in subjects undergoing Tl-201 SPECT with ATP.

Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Findings of Post Traumatic Lymphangioma in a Young Adult Male.

The authors report the case of a 34-year-old male, who underwent a fluorine-18 fluoro deoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) scan 7 years after trauma for the evaluation of multifocal masses in the right iliac and right inguinal areas. CT findings showed multifocal low density masses and 18F-FDG PET revealed slightly increased uptake (maximum standardized uptake value [SUVmax] 3.1). These findings did not exclude the possibility of a benign or malignant lesion. To achieve differential diagnosis, partial surgical excision was performed and a pathologic examination subsequently revealed lymphangioma. Here, the authors describe the 18F-FDG PET/CT findings of a rare case of lymphangioma resulting from trauma.

Correlation Between Apparent Diffusion Coefficients and Standardized Uptake Values in Hybrid (18)F-FDG PET/MR: Preliminary Results in Rectal Cancer.

PURPOSE: Fluorine-18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and diffusion-weighted magnetic resonance imaging (DWI) share the same role in clinical oncology and it is feasible to obtain the standardized uptake value (SUV) and apparent diffusion coefficient (ADC) simultaneously by emerging the hybrid positron emission tomography/magnetic resonance (PET/MR). This study investigated the correlation between the ADCs of rectal cancer lesions and their SUVs derived from hybrid PET/MR. METHODS: Nine patients with histologically proven rectal adenocarcinoma (5 men, 4 women; mean age, 70 ± 15.91 years) underwent torso (18)F-FDG PET/CT and regional hybrid (18)F-FDG PET/MR sequentially. A fixed threshold value of 40 % of maximum uptake was used to determine tumor volume of interest (VOI) on PET image; SUVmax, SUVpeak, and SUVmean were calculated automatically. A single freehand region of interest (ROI) was drawn on high b-value (b1000) DWI image and copied to corresponding ADC map to determine the ADCmean of rectal cancer lesion. Spearman's rank correlation coefficient (ρ) was calculated to determine the correlation between SUVs and ADC values. RESULTS: SUVmax, SUVpeak, and SUVmean derived by hybrid PET/MR were 12.35 ± 4.66 (mean ± standard deviation), 9.66 ± 3.15 and 7.41 ± 2.54, respectively. The ADCmean value of rectal cancer lesions was 1.02 ± 0.08 × 10(-3)mm(2)/s. ADCmean was significantly and inversely correlated with SUV values (SUVmax, ρ = -0.95, p < 0.001; SUVpeak, ρ = -0.93, p < 0.001; SUVmean, ρ = -0.91, p = 0.001). CONCLUSIONS: This preliminary hybrid PET/MR study demonstrates a significant inverse correlation exists between metabolic activity on (18)F-FDG PET and water diffusion on DWI in rectal cancer.

Adenosine-induced long-standing postischemic left ventricular dysfunction evaluated with gated SPECT.

OBJECTIVES: This study was performed to determine the after-effects of pharmacologic stress (adenosine) on left ventricular (LV) function-end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (LVEF)-with Tl-201 and Tc-99m MIBI SPECT. METHODS: A total of 263 patients were grouped according to the time interval between isotope injection and imaging. Group A: within 1 hour (n = 99; men, n = 48; women, n = 51; mean age: 63.2 years), subgrouped as patients with no perfusion defect (NPD; n = 61), reversible defect (RD; n = 33), and fixed defect (FD; n = 5). Group B: 1 to 2 hours (n = 110; men, n = 66; woman, n = 44; mean age, 63 years), NPD (n = 64), RD (n = 26), and FD (n = 20). 3) Group C: 2 to 3 hours (n = 54; men, n = 30; women, n = 24; mean age, 62 years); NPD (n = 22), RD (n = 17), and FD (n = 15). All patients were in sinus rhythm during the study and had no prior history of myocardial infarction. RESULTS: In group A, in the patients with RD, poststress LVEF was significantly depressed after adenosine infusion (53.1 +/- 9.5% vs 58.3 +/- 10.2%, P < 0.001) and showed a wall motion abnormality, which was worse after stress than during rest. The mean difference in LVEF (DeltaLVEF) between rest and stress was 5.2%. The DeltaLVEF in those patients with RD was significantly higher than that in the NPD (0.9%, P < 0.01) or FD (2.1%, P < 0.05) subgroups. Twenty of the 33 patients (60.6%) with RD showed an increase in LVEF > or = 5% from poststress to rest, and the poststress ESV (43.3 +/- 19.0 mL) was significantly higher than the ESV (38.5 +/- 18.4 mL, P < 0.01) at rest, but there was no significant difference in the EDV (90.5 +/- 26.4 vs 89.7 +/- 26.2 mL). In group B, DeltaLVEF was 1.5%, 4.4%, and 1.2% in patients with NPD, RD, and FD respectively. In group C, DeltaLVEF was 2.5%, 3.2%, and 0.9% in patients with NPD, RD, and FD respectively, and there was no significant difference in DeltaLVEF among patients. In group C, 4 of 17 patients (23.5%) with RD showed an increase in LVEF > or = 5% from poststress to rest. CONCLUSION: These results showed that adenosine stress-induced postischemic LV dysfunction is well noted on early quantitative gated SPECT in patients with RD and can also be observed on delayed gated SPECT, even though the incidence of LV dysfunction is less than that in early gated SPECT.

F-18 FDG PET/MRI findings of primary breast lymphoma in two cases: FDG PET/MRI findings of primary breast lymphoma.

We present the integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) findings of diffuse large B-cell lymphoma involving the breast in two women. They were admitted with palpable breast masses. PET/MRI revealed high (18)F-fluorodeoxyglucose (FDG) uptake in multinodular enhancing masses without other FDG-avid foci. Diffusion-weighted imaging showed restricted water diffusion and dynamic contrast MRI showed rapid increase and washout kinetics. High FDG accumulation in tumor is related to washout kinetics. We present the usefulness of integrated PET/MRI for lesion characterization and total body staging in breast lymphoma.