Jae Seon Eo

Prognostic value of metabolic tumor volume measured by FDG-PET/CT in patients with cervical cancer

OBJECTIVEnTo determine if preoperative metabolic tumor volume (MTV) measured by integrated (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (FDG-PET/CT) imaging has prognostic value in patients with cervical cancer treated primarily with radical hysterectomy.nnnMETHODSnPatients with FIGO stage IB to IIA cervical cancer were imaged with FDG-PET/CT before radical surgery. MTV was measured from attenuation-corrected FDG-PET/CT images using a standard uptake value (SUV)-based automated contouring program. We evaluated the relationship of MTV to disease-free survival (DFS).nnnRESULTSnA total of 63 patients were included in the study. The cut-off value for predicting recurrence was determined using a receiver operating characteristic (ROC) curve. MTV in this study was found to be correlated with lymph node (LN) metastasis, parametrium (PM) involvement, FIGO stage, and SUV(max). In univariate analysis, MTV≥23.4 mL (HR 1.017, 95% confidence interval (CI) 1.005-1.029, P=0.004), SUV(max)≥9.5 (HR 5.198, 95% CI 1.076-25.118, P=0.04), LN metastasis (HR 12.338, 95% CI 1.541-98.813, P=0.018), PM involvement (HR 14.274, 95% CI 1.785-114.149, P=0.012), and lymphovascular space invasion (HR 8.871, 95% CI 1.104-71.261, P=0.04), were related to DFS. In multivariate analyses, age (HR 0.748, 95% CI 0.587-0.952, P=0.018) and MTV≥23.4 mL (HR 49.559, 95% CI 1.257-1953.399, P=0.037) were determined to be independent prognostic factors of DFS.nnnCONCLUSIONnPreoperative MTV is an independent prognostic factor for DFS in patients with cervical cancer treated by radical surgery.

Imaging sensitivity of dedicated positron emission mammography in relation to tumor size

Positron emission mammography (PEM) has been reported to have higher sensitivity than whole-body positron emission tomography (PET)due to higher spatial resolution. However, no direct evidence exists regarding the imaging sensitivity of PEM related to lesion size. In the present study, imaging sensitivity of PEM was investigated in relation to pathologically confirmed tumor size. A total of 113 breast lesions from 101 patients were included in the analysis. The patients underwent (18)F-fluorodeoxyglucose (FDG) PEM and whole-body PET/computed tomography (CT) before surgical resection, and images were analyzed visually and quantitatively using the tumor-to-normal-tissue uptake ratio (TNR). Tumors were classified into four groups based on size using pathologic results, and sensitivities of PEM and PET/CT were compared in the overall subjects and in each size group. In visual analysis, PEM showed significantly higher imaging sensitivity than PET/CT (95% vs. 87%; P = 0.004), which was more definite in the small-tumor groups. In quantitative analysis, the TNR of PEM was significantly higher than that of PET/CT in the small-tumor groups, whereas no difference was found in the overall group. With a cutoff TNR of 2.5, PEM showed significantly higher sensitivity than PET/CT in the overall and small-tumor groups. In conclusion, PEM had higher imaging sensitivity than PET/CT, particularly in small tumors. The results suggest that PEM may be used for diagnosis and characterization of small lesions as a supplementary imaging modality for PET/CT.

Angiogenesis imaging in myocardial infarction using 68Ga-NOTA-RGD PET: characterization and application to therapeutic efficacy monitoring in rats.

Objective68Ga-NOTA-RGD PET is a newly developed molecular imaging for angiogenesis. In this study, 68Ga-NOTA-RGD PET was used to investigate imaging characteristics in a rat myocardial infarction (MI) model and to monitor the efficacy of an angiogenesis induction therapy. Materials and methods68Ga-NOTA-RGD PET was performed serially in rats with MI or sham operation, and myocardial uptake was analyzed with respect to time duration and tissue characteristics. Subsequently, 68Ga-NOTA-RGD PET was serially performed for therapeutic efficacy monitoring in MI-induced rats, which were treated with basic fibroblast growth factor (bFGF) injection or saline injection. Image findings were compared with the final change in MI lesion. Results68Ga-NOTA-RGD uptake was significantly increased in MI lesion and gradually decreased over time. 68Ga-NOTA-RGD uptake in the infarcted tissue corresponded with vascular endothelial growth factor expression and macrophage accumulation. In monitoring of therapeutic efficacy, the lesion uptake in the bFGF-injected group was significantly higher than that of the saline-injected and sham-operated groups on the first day. However, no significant differences were observed between bFGF and saline-injected groups at subsequent time points, corresponding to the final infarct size change. Conclusion68Ga-NOTA-RGD PET would be a useful angiogenesis imaging modality in MI for assessment of pathophysiology or monitoring of therapeutic efficacy.

Intermodality comparison between 3D perfusion CT and 18F-FDG PET/CT imaging for predicting early tumor response in patients with liver metastasis after chemotherapy: Preliminary results of a prospective study

OBJECTIVESnTo evaluate the feasibility of 3D perfusion CT for predicting early treatment response in patients with liver metastasis from colorectal cancer.nnnMETHODSnSeventeen patients with colon cancer and liver metastasis were prospectively enroled to undergo perfusion CT and 18F-FDG-PET/CT before and after one-cycle of chemotherapy. Two radiologists and three nuclear medicine physicians measured various perfusion CT and PET/CT parameters, respectively from the largest hepatic metastasis. Baseline values and reduction rates of the parameters were compared between responders and nonresponders. Spearman correlation test was used to correlate perfusion CT and PET/CT parameters, using RECIST criteria as reference standard.nnnRESULTSnNine patients responded to treatment, eight patients were nonresponders. Baseline SUVmean30 on PET/CT, reduction rates of 30% metabolic volume and 30% lesion glycolysis (LG30) on PET/CT and blood flow (BF) and flow extraction product (FEP) on perfusion CT after chemotherapy were significantly different between responders and nonresponders (P=0.008-0.046). Reduction rates of BF (correlation coefficient=0.630) and FEP (correlation coefficient=0.578) significantly correlated with that of LG30 on PET/CT (P<0.05).nnnCONCLUSIONnCT perfusion parameters including BF and FEP may be used as early predictors of tumor response in patients with liver metastasis from colorectal cancer.

Validation of Simple Quantification Methods for 18F-FP-CIT PET Using Automatic Delineation of Volumes of Interest Based on Statistical Probabilistic Anatomical Mapping and Isocontour Margin Setting

Purpose18F-FP-CIT positron emission tomography (PET) is an effective imaging for dopamine transporters. In usual clinical practice, 18F-FP-CIT PET is analyzed visually or quantified using manual delineation of a volume of interest (VOI) for the striatum. In this study, we suggested and validated two simple quantitative methods based on automatic VOI delineation using statistical probabilistic anatomical mapping (SPAM) and isocontour margin setting.MethodsSeventy-five 18F-FP-CIT PET images acquired in routine clinical practice were used for this study. A study-specific image template was made and the subject images were normalized to the template. Afterwards, uptakes in the striatal regions and cerebellum were quantified using probabilistic VOI based on SPAM. A quantitative parameter, QSPAM, was calculated to simulate binding potential. Additionally, the functional volume of each striatal region and its uptake were measured in automatically delineated VOI using isocontour margin setting. Uptake-volume product (QUVP) was calculated for each striatal region. QSPAM and QUVP were compared with visual grading and the influence of cerebral atrophy on the measurements was tested.ResultsImage analyses were successful in all the cases. Both the QSPAM and QUVP were significantly different according to visual grading (Pu2009<u20090.001). The agreements of QUVP or QSPAM with visual grading were slight to fair for the caudate nucleus (κu2009=u20090.421 and 0.291, respectively) and good to perfect to the putamen (κu2009=u20090.663 and 0.607, respectively). Also, QSPAM and QUVP had a significant correlation with each other (Pu2009<u20090.001). Cerebral atrophy made a significant difference in QSPAM and QUVP of the caudate nuclei regions with decreased 18F-FP-CIT uptake.ConclusionSimple quantitative measurements of QSPAM and QUVP showed acceptable agreement with visual grading. Although QSPAM in some group may be influenced by cerebral atrophy, these simple methods are expected to be effective in the quantitative analysis of 18F-FP-CIT PET in usual clinical practice.

Pulmonary artery sarcoma detected on F-18 FDG PET/CT as origin of multiple spinal metastases.

A 67-year-old man with back pain was diagnosed as having multiple spinal metastases on MRI. On CT scan, only a filling defect in the right pulmonary artery was observed and suspected as venous thromboembolism. On F-18 fluorodeoxyglucose (FDG) PET/CT, intense hypermetabolism was observed in the right pulmonary artery in addition to the metastatic spine lesions. Biopsy confirmed the lesion as a primary pulmonary artery sarcoma (PAS), and the spine lesions as metastases of PAS. Although PAS is rare and its bone metastasis presenting initial symptom is extremely rare, FDG PET/CT is an effective diagnostic modality for PAS, not only in discrimination from venous thromboembolism, but also in workup of metastatic origin.

Evaluation of immediate post-stress wall motion on adenosine stress/rest Thallium-201 gated myocardial SPECT

As early as 10xa0min after adenosine stress, immediate post-stress wall motion can be evaluated on adenosine stress/rest Tl-201 gated myocardial SPECT. To widen the applications of Tl-201 in gated SPECT, we investigated the reproducibility of LV parameters (EF, EDV, and ESV), and the diagnostic competency of immediate post-stress wall motion evaluations obtained by adenosine stress/rest Tl-201 gated myocardial SPECT. Myocardial perfusion and wall motion were evaluated using a 5-point scoring system in 20-segment model using Cedas automatic gated software (AutoQUANT 4.3.1). The reproducibilities of LV parameters were examined through repeated acquisition (n=31). Diagnostic competency was evaluated vs. coronary angiography, and multivariate logistic regression analysis was used to determine whether stress abnormal perfusion (SSSp), stress abnormal wall motion (SSSwm), or reversible abnormal wall motion (SDSwm) predict coronary stenosis (>u200970%) (n=60). Two standard deviations for immediate post-stress wall motion were smaller than those for rest at EF (8.6 vs. 10.7%) and ESV (6.0xa0ml vs 8.4xa0ml). Univariate logistic regression analysis identified SSSp (p=0.006), SSSwm (p=0.016), and SDSwm (p=0.020) are significant predictors, but only SSSp (p=0.013) and SDSwm (p=0.039) were found to be significant by multivariate analysis. In addition, SSSwm or SDSwm were able to find undetected coronary artery disease in 54.5% (6/11) of patients with normal perfusion. We conclude that Tl-201 can be successfully applied to gated SPECT for immediate post-stress wall motion evaluation, and that reversible wall motion abnormality on adenosine stress/rest Tl-201 gated myocardial SPECT is an independent predictor of significant coronary artery disease.

Use of granulocyte colony-stimulating factor for fluorine-18-fluorodeoxyglucose labeling in human leukocytes.

ObjectiveInsufficient labeling efficiency and poor retention of radioactivity are the considerable shortcomings of fluorine-18-fluorodeoxyglucose (18F-FDG) labeling in human leukocytes. This study was conducted toevaluate the feasibility of using granulocyte colony-stimulating factor (G-CSF) to improve 18F-FDG labeling in human leukocytes. MethodsLeukocyte separation was performed using methods reported earlier. Separated leukocytes were preincubated with G-CSF or insulin at 37°C for 1 h. Afterpreincubation, labeling was performed with 18F-FDG (37–74 MBq) at 37°C for 30 min. Retained radioactivity was assessed at 1–4 h after labeling by the same method described in earlier reports. The viability of labeled leukocytes was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. ResultsLabeling efficiency of leukocytes preincubated withG-CSF, G-CSF with insulin, insulin, and control leukocytes was 52.1±8.9%, 49.9±10.5%, 40.3±7.7%, and 40.3±6.0%, respectively. G-CSF significantly increased the labeling efficiency compared with insulin (P=0.005) and control (P=0.004). In leukocytes preincubated with G-CSF, 77.0±1.2%, and 59.0±1.8% of radioactivity was retained at 1 and 3 h after labeling. There was no significant difference in retained radioactivity compared with that of leukocytes with different treatment at all time points. Furthermore, no significant difference in viabilities among leukocytes with different treatments was observed. ConclusionUse of G-CSF significantly improved 18F-FDG labeling efficiency without a significant effect on cell viability and retention of radioactivity.

Behavior and Awareness of Thyroid Cancer Patients in Korea Having Non-Hospitalized Low-Dose Radioiodine Treatment with Regard to Radiation Safety

PurposeWith the recent increase in incidence of thyroid cancer, non-hospitalized low-dose (NH-LD) radioiodine treatment (RIT) has also increased rapidly. The radioactivity limit that is allowed to be administered without hospitalization depends on individual calculation, based partly on patients’ behavior. In this study, Korean patients’ behavior in relation to radiation safety in NHLD RIT was surveyed.MethodsA total of 218 patients who underwent NH-LD RIT of 1.1xa0GBq 131I in a single center were surveyed. The patients underwent RIT with a standard protocol and the survey was performed by interview when they visited subsequently for a whole-body scan. The survey questionnaire included three parts of questions: general information, behavior relating to isolation during RIT, and awareness of radiation safety.ResultsAfter administration of radioiodine, 40% of patients who returned home used mass transportation, and another 47% went home by taxi or in car driven by another person. Isolation at home was generally sufficient. However, 7% of patients did not stay in a separate room. Among the 218 patients, 34% did not go home and chose self-isolation away from home, mostly due to concerns about radiation safety of family members. However, the places were mostly public places, including hotels, resorts, and hospitals. About half of the patients replied that access to radiation safety information was not easy and their awareness of radiation safety was not satisfactory. As a result, 45% of patients wanted hospitalized RIT.ConclusionsIn many countries, including Korea, RIT is continuously increasing. Considering the radiation safety of patients’ family members or the public and the convenience of patients, the pretreatment education of patients should be enhanced. In addition, the hospitalization of patients having low-dose therapy is recommended to be seriously considered and expanded, with the expansion of dedicated treatment facilities.

Automated Analysis of 123I-beta-CIT SPECT Images with Statistical Probabilistic Anatomical Mapping

BackgroundPopulation-based statistical probabilistic anatomical maps have been used to generate probabilistic volumes of interest for analyzing perfusion and metabolic brain imaging. We investigated the feasibility of automated analysis for dopamine transporter images using this technique and evaluated striatal binding potentials in Parkinson’s disease and Wilson’s disease.Materials and MethodsWe analyzed 2β-Carbomethoxy-3β-(4-123I-iodophenyl)tropanexa0(123I-beta-CIT) SPECT images acquired from 26 people with Parkinson’s disease (M:Fu2009=u200911:15, mean ageu2009=u200949u2009±u200912xa0years), 9 people with Wilson’s disease (M: Fu2009=u20096:3, mean ageu2009=u200926u2009±u200911xa0years) and 17 normal controls (M:Fu2009=u20095:12, mean ageu2009=u200939u2009±u200916xa0years). A SPECT template was created using striatal statistical probabilistic map images. All images were spatially normalized onto the template, and probability-weighted regional counts in striatal structures were estimated. The binding potential was calculated using the ratio of specific and nonspecific binding activities at equilibrium. Voxel-based comparisons between groups were also performed using statistical parametric mapping.ResultsQualitative assessment showed that spatial normalizations of the SPECT images were successful for all images. The striatal binding potentials of participants with Parkinson’s disease and Wilson’s disease were significantly lower than those of normal controls. Statistical parametric mapping analysis found statistically significant differences only in striatal regions in both disease groups compared to controls.ConclusionWe successfully evaluated the regional 123I-beta-CIT distribution using the SPECT template and probabilistic map data automatically. This procedure allows an objective and quantitative comparison of the binding potential, which in this case showed a significantly decreased binding potential in the striata of patients with Parkinson’s disease or Wilson’s disease.