Different roles of surveillance positron emission tomography according to the histologic subtype of non-Hodgkin’s lymphoma

Background/Aims@#Although the use of surveillance 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is discouraged in patients with diffuse large B-cell lymphoma, its usefulness in different subtypes has not been thoroughly investigated. @*Methods@#We retrospectively evaluated 157 patients who showed positive results on surveillance FDG-PET/CT every 6 months following complete response for up to 5 years. All of the patients also underwent biopsies. @*Results@#Seventy-eight (49.6%) of 157 patients had true positive results; the remaining 79 (50.3%), including eight (5.1%) with secondary malignancies, were confirmed to yield false positive results. Among the 78 patients with true positive results, the disease in seven (8.9%) had transformed to a different subtype. The positive predictive value (PPV) of FDG-PET/CT for aggressive B-cell non-Hodgkin’s lymphoma (NHL) was lower than that for indolent B-cell or aggressive T-cell NHL (p = 0.003 and p = 0.018, respectively), especially in patients with a low/low-intermediate international prognostic index (IPI) upon a positive PET/CT finding. On the other hand, indolent B-cell and aggressive T-cell NHL patients showed PPVs of > 60%, including those with low/low-intermediate secondary IPIs. @*Conclusions@#The role of FDG-PET/CT surveillance is limited, and differs according to the lymphoma subtype. FDG-PET/CT may be useful in detecting early relapse in patients with aggressive T-cell NHL, including those with low/low-intermediate risk secondary IPI; as already known, FDG-PET/CT has no role in aggressive B-cell NHL. Repeat biopsy should be performed to discriminate relapse or transformation from false positive findings in patients with positive surveillance FDG-PET/CT results.

Choroid Plexus as the Best Reference Region for Standardized Uptake Value Analysis on C11-Acetate PET/CT for Grading and Predicting Prognosis in Patients with Cerebral Gliomas / 대한핵의학회잡지

Purpose@#We aimed to compare different reference regions and select one with the most clinical relevance on C11-acetate (ACE) positron emission tomography/computed tomography (PET/CT) in patients with cerebral glioma. @*Methods@#We retrospectively reviewed 51 patients with cerebral glioma who underwent baseline ACE PET/CT at diagnosis.Other than the standardized uptake value (SUV) of the primary tumor, SUVs of the reference regions including the normal gray matter, white matter, choroid plexus, and cerebellum were measured. Then, the SUV ratio (SUVR = tumor SUV max /reference region SUV mean ) was calculated. The effect of patient age on the SUV mean of each reference was examined and the SUVRs of each reference region were compared between grades. age, sex, tumor size, histological grades, SUVR , and the presence of isocitrate dehydrogenase (IDH) mutation were included for survival analyses. @*Results@#Except for the cerebellum showing a mild negative correlation, we found no correlations between age and SUV mean using the gray matter, white matter, and choroid plexus (r = − 0.280, P < = 0.047). Only the SUVR -choroid plexus was able to differentiate between the WHO grades (Grade II vs. III, P < = 0.035; grade III vs. IV, P < < 0.001; grade II vs. IV, P < 0.001). Multivariate Cox proportional hazards models found that the SUVR-choroid plexus and IDH mutation were statistically significant for predicting OS. @*Conclusion@#Of the different reference regions used for grading cerebral gliomas, the choroid plexus was found to be the most optimal.In addition, the SUV ratio is useful to predict the overall survival in the model with the choroid plexus as a reference region.

Evaluation of ¹⁸F-FDG PET/CT Parameters for Detection of Lymph Node Metastasis in Cutaneous Melanoma / 대한핵의학회잡지

PURPOSE: The purpose of this study was to investigate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) parameters in the detection of regional lymph node (LN) metastasis in patients with cutaneous melanoma.METHODS: We evaluated patients with cutaneous melanoma who underwent FDG PET/CT for initial staging or recurrence evaluation. A total of 103 patients were enrolled, and 165 LNs were evaluated. LNs that were confirmed pathologically or by follow-up imaging were included in this study. PET parameters, including maximum standardized uptake value (SUVmax), total lesion glycolysis and tumour-to-liver ratio, were used to determine the presence of metastases, and the results were compared with CT-determined LN metastasis. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off values of the FDG PET parameters.RESULTS: A total of 93 LNs were malignant, and 84 LNs were smaller than 10 mm. In all 165 LNs, an SUVmax of >2.51 showed a sensitivity of 73.1%, a specificity of 88.9%, and an accuracy of 80.0% in detecting metastatic LNs. CT showed a higher specificity (87.3%) and lower accuracy (65.5%). For non-enlarged regional LNs ( < 10 mm), an SUVmax cut-off value of 1.4 showed the highest negative predictive value (81.3%). For enlarged LNs (≥10 mm), an SUVmax cut-off value of 2.4 showed the highest sensitivity (90.7%) and accuracy (88.9%) in detecting metastatic LNs.CONCLUSIONS: In patients with cutaneous melanoma, an SUVmax of >2.4 showed a high sensitivity (91%) and accuracy (89%) in detecting metastasis in LNs ≥1 cm, and LNs < 1 cm with an SUVmax < 1.4 were likely to be benign.

Evaluation of ¹⁸F-FDG PET/CT Parameters for Detection of Lymph Node Metastasis in Cutaneous Melanoma / 대한핵의학회잡지

PURPOSE@#The purpose of this study was to investigate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) parameters in the detection of regional lymph node (LN) metastasis in patients with cutaneous melanoma.@*METHODS@#We evaluated patients with cutaneous melanoma who underwent FDG PET/CT for initial staging or recurrence evaluation. A total of 103 patients were enrolled, and 165 LNs were evaluated. LNs that were confirmed pathologically or by follow-up imaging were included in this study. PET parameters, including maximum standardized uptake value (SUVmax), total lesion glycolysis and tumour-to-liver ratio, were used to determine the presence of metastases, and the results were compared with CT-determined LN metastasis. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off values of the FDG PET parameters.@*RESULTS@#A total of 93 LNs were malignant, and 84 LNs were smaller than 10 mm. In all 165 LNs, an SUVmax of >2.51 showed a sensitivity of 73.1%, a specificity of 88.9%, and an accuracy of 80.0% in detecting metastatic LNs. CT showed a higher specificity (87.3%) and lower accuracy (65.5%). For non-enlarged regional LNs ( 2.4 showed a high sensitivity (91%) and accuracy (89%) in detecting metastasis in LNs ≥1 cm, and LNs < 1 cm with an SUVmax < 1.4 were likely to be benign.

Usefulness of SPECT/CT in Parathyroid Lesion Detection in Patients with Thyroid Parenchymal (99m)Tc-Sestamibi Retention / 대한핵의학회잡지

PURPOSE: Parathyroid adenoma detection with dual-phase (99m)Tc-sestamibi (MIBI) scintigraphy depends on differential MIBI washout from thyroid. However, autoimmune thyroid disease (AITD) may cause MIBI to be retained in the thyroid gland and reduce parathyroid detection.We evaluated the impact of AITD on MIBI thyroid retention and additional benefit of SPECT/CT in these patients.METHODS: Dual phase planar MIBI and SPECT/CT was performed on 82 patients. SPECT/CTwas performed immediatelyafter delayed planar scan. Thyroid density (Hounsfield unit, CT-HU) and size were measured on CT component of SPECT/CT. MIBI uptake in early scans and retention in delayed scans were visually graded and correlated with clinical factors and CT findings. Finally, planar and SPECT/CT findings were compared for parathyroid lesion visualization according to thyroid MIBI retention.RESULTS: In early scan, multivariate analysis showed only thyroid size predicted early uptake. In delayed scan, multivariate analysis showed higher visual grade in early scan, lower CTHU or AITD were significant predictors for delayed thyroid parenchymal retention. Overall, ten more parathyroid lesions were visualized on SPECT/CT compared to planar scans (57 vs. 47, p = 0.002). SPECT/CT was especially more useful in patients with thyroidal MIBI retention, as eight out of the ten additional lesions detected were found in patients with thyroid MIBI retention.CONCLUSION: AITD is an important factor for MIBI thyroid parenchymal retention on delayed scans, and may impede parathyroid lesion detection. Patients with MIBI retention in the thyroid parenchyma on delayed scans are likely to benefit from an additional SPECT/CT.

Prognostic Impact of Ultrasonography Features and 18F-Fluorodeoxyglucose Uptake in Patients With Papillary Thyroid Microcarcinoma

OBJECTIVES: To evaluate the prognostic impact of ultrasonography (US) features and 18F-fluorodeoxyglucose (18F-FDG) uptake in patients with papillary thyroid microcarcinoma (PTMC). METHODS: This study included 74 patients with a single PTMC diagnosed pathologically. Patients underwent total thyroidectomy, or near-total thyroidectomy and staging thyroid US and positron emission tomography (PET) were performed prior to surgery. US features of thyroid nodules were reviewed retrospectively and the maximum standard uptake value (SUV) of nodules was semiquantitatively analyzed on 18F-FDG PET/computed tomography (CT). Patients were followed-up for recurrence, which was defined as PTC on cytology results, elevated serum thyroglobulin (Tg) or anti-Tg antibody levels, or uptake on whole-body scintigraphy. We used univariate and multivariate analyses to evaluate whether poor prognostic outcomes were associated with US features or SUV values derived from PET/CT of nodules. In addition, subjects were divided into 2 groups for subgroup analyses: one with nodules equal to or larger than 5 mm and one with nodules smaller than 5 mm. RESULTS: Among the 74 patients, there was no recurrence. Thus we evaluated the correlation between SUV value and US features with poor prognostic factors of PTMC which included extrathyroid extension, central and lateral lymph node (LN) metastasis. However no clinicopathologic factors were associated with extrathyroid extension, central LN metastasis, or lateral LN metastasis. CONCLUSION: In patients with PTMC, US features and SUV values on FDG-PET were not related to extrathyroid extension or LN metastasis. However, future studies with a larger sample size and longer follow-up should be performed to verify the results of this study.

A Case of von Hippel-Lindau Disease with Colorectal Adenocarcinoma, Renal Cell Carcinoma and Hemangioblastomas / Journal of the Korean Cancer Association, 대한암학회지

von Hippel-Lindau (VHL) disease is an autosomal dominant inherited tumor syndrome associated with mutations of the VHL tumor suppressor gene located on chromosome 3p25. The loss of functional VHL protein contributes to tumorigenesis. This condition is characterized by development of benign and malignant tumors in the central nervous system (CNS) and the internal organs, including kidney, adrenal gland, and pancreas. We herein describe the case of a 74-year-old man carrying the VHL gene mutation who was affected by simultaneous colorectal adenocarcinoma, renal clear cell carcinoma, and hemangioblastomas of CNS.

Prognostic Value of 18F-Fluorodeoxyglucose Positron Emission Tomography in Patients with Resectable Pancreatic Cancer

PURPOSE: We evaluated the prognostic value of 18F-2-fluoro-2-deoxyglucose positron emission tomography (FDG PET) in patients with resectable pancreatic cancer. MATERIALS AND METHODS: We retrospectively reviewed the medical records of pancreatic cancer patients who underwent curative resection, which included 64 consecutive patients who had preoperative FDG PET scans. For statistical analysis, the maximal standardized uptake value (SUVmax) of primary pancreatic cancer was measured. Survival time was estimated by the Kaplan-Meier method, and Cox's proportional hazard model was used to determine whether SUVmax added new predictive information concerning survival together with known prognostic factors. p3.5) showed significantly shorter OS and DFS than the low SUVmax group. Multivariate analysis of OS and DFS showed that both high SUVmax and poor tumor differentiation were independent poor prognostic factors. CONCLUSION: Our study showed that degree of FDG uptake was an independent prognostic factor in pancreatic cancer patients who underwent curative resection.

Clinical Significance of Myocardial Uptake on F-18 FDG PET/CT Performed in Oncologic Patients / 핵의학분자영상

PURPOSE: F-18 fluorodeoxyglucose (FDG) uptake of myocardium is influenced by various factors. Increased glycolysis, and subsequent increased F-18 FDG uptake has been reported in ischemic cardiomyopathy. However, clinical significance of incidentally found myocardial F-18 FDG uptake has not been clarified. We retrospectively reviewed the degree and pattern of myocardial uptake in patients without history of ischemic heart disease who underwent torso F-18 FDG PET/CT for evaluation of neoplastic disease. MATERIALS AND METHODS: From January 2005 to June 2009, 77 patients who underwent F-18 FDG PET/CT and Tc-99m sestamibi stress/rest SPECT within 3 months were enrolled. RESULTS: Of 77 patients, 55 (71.4%) showed increased F-18 FDG uptake in the myocardium. In this population, 40 showed uniform uptake pattern, while 15 showed focal uptake. In patients with uniform uptake, 17 showed decreased uptake in the septum without perfusion defect on myocardial SPECT. Remaining 23 patients showed uniform uptake, with 1 reversible perfusion defect and 1 fixed perfusion defect. In 15 patients with focal uptake, 9 showed increased F-18 FDG uptake in the base, and only 1 of them showed reversible perfusion defect on myocardial SPECT. In the remaining 6 focal uptake group, 4 had reversible perfusion defect in the corresponding wall, and 1 had apical hypertrophy. CONCLUSION: We demonstrated that septal defect pattern and basal uptake pattern in the myocardium may represent normal variants. Focal myocardial uptake other than normal variants on oncologic torso F-18 FDG PET/CT with routine fasting protocol may suggest ischemic heart disease, thus further evaluation is warranted.

Radiation Safety Issues Related to Sentinel Lymph Node Biopsy using Radioactive Colloid: Commentary on "Exposure of Surgical Staff to Radiation" / 한국유방암학회지

No abstract available.

The value of Dedicated Tc-99m MIBI Scintimammography in the Evaluation of Patients with Palpable Breast Lesions in Comparison with Mammography: Preliminary Result / 핵의학분자영상

PURPOSE: There are few studies evaluating the usefulness of dedicated high-resolution scintimammography and no studies using delayed washout with this dedicated high resolution scintimammography for the evaluation of breast lesions. We underwent this study to evaluate the clinical usefulness of Tc-99m MIBI in evaluating patients with palpable breast lesions using dedicated high-resolution scintimammography. MATERIALS AND METHODS: This study included 19 patients with 23 palpable breast lesions who underwent mammography. Tc-99m MIBI was taken to further characterize these lesions. Scintimammography images were acquired with standard craniocaudal and mediolateral oblique views and delayed images were additionally taken. Final conclusions were based on histopathology, either by biopsy or mastectomy results. RESULTS: Eighteen lesions were malignant and five were benign. Mammography was indeterminate for thirteen lesions, nine of those were malignant. Mammography also categorized one lesion as benign in a dense breast, but scintimammography and pathology results showed malignancy. Of the five benign lesions, two were visible on scintimammography, but delayed images showed washout. CONCLUSION: Based on our preliminary results, dedicated high resolution scintimammography seems to be very useful in characterizing palpable lesions that were indeterminate or negative on mammography.

FDG Uptake in the Pathologically Proven Papillary Thyroid Cancer / 핵의학분자영상

PURPOSE: Metastatic thyroid cancers with I-131 uptake have been known to show no increase of FDG uptake whereas those without I-131 uptake tend to demonstrate increased uptake on PET. In this study, we evaluated the degree of FDG uptake in primary thyroid cancers of papillary histology before surgery. MATERIAL AND METHODS: Forty FDG PET studies were performed on the patients who had papillary cancer proven by fine needle aspiration. The degree of FDG uptake was visually categorized as positive or negative (positive if the tumor showed discernible FDG; negative if the tumor didn't) and the peak standard uptake value (peak SUV) of the papillary thyroid cancer (PTC) were compared with the size of PTC. RESULTS: The mean size of 26 PTC with positive FDG uptake was 1.9+/-1.4 cm(0.5~5 cm). In 13 PTC with negative FDG uptake, the mean size of those was 0.5+/-0.2 cm (0.2~0.9 cm). All PTC larger than 1cm (2.5+/-1.4 cm, 1~5 cm) have positive FDG uptake (peak SUV=6.4+/-5.7, 1.7~22.7). Among the micropapillary thyroid cancer (microPTC; PTC smaller than 1cm), 8 microPTC show positive FDG uptake(peak SUV=2.9+/-1.3, 1.7~5.5), while 13 microPTC show negative finding(peak SUV=1.3+/-0.2, 1.1~1.7). The size of microPTC with positive FDG uptake is significantly larger than that of microPTC with negative FDG uptake (0.7+/-0.1 cm vs 0.4+/-0.2 cm, p=0.01). CONCLUSION: All PTCs larger than 1cm show positive FDG uptake in our study. In other words, thyroid lesions larger than 1cm with negative FDG uptake are unlikely to be PTC. So far, only poorly differentiated thyroid cancers are known to show increased FDG uptake. Our results seem to be contradictory to what is known in the literature. Further study is needed to understand better the significance of increased FDG uptake in PTC in relation to expression of NIS and GLUT.