Breast Sparganosis Incidentally Detected by FDG PET/CT

하승균,오소원,김유경,이안,안영준,손길수,배정원,이재복,우상욱 대한핵의학회 2013 핵의학 분자영상 Vol.47 No.2

Sparganosis is a rare, parasitic infection that is caused by the plercercoid tapeworm larvae of the genus Spirometra. Sparganosis is transmitted by ingestion of larvaecontaining water or intermediate hosts, such as raw amphibians,and usually presented with a subcutaneous nodule in the abdominal wall, extremities, and genital organs. Among the various involved organs, the breast is a seldom encountered site for sparganosis. However, breast sparganosis has clinical importance, since it is generally presented with an indolent palpable mass that mimics malignancy, even without evidence of inflammation. Herein, we report a case of breast sparganosis that was detected incidentally by FDG PET/CT during staging work ups in a patient with gall bladder cancer.

Radiomics in Oncological PET/CT: a Methodological Overview

하승균,최홍윤,팽진철,천기정 대한핵의학회 2019 핵의학 분자영상 Vol.53 No.1

Radiomics is a medical imaging analysis approach based on computer-vision. Metabolic radiomics in particular analyses the spatial distribution patterns of molecular metabolism on PET images. Measuring intratumoral heterogeneity via image is one of the main targets of radiomics research, and it aims to build a image-based model for better patient management. The workflow of radiomics using texture analysis follows these steps: 1) imaging (image acquisition and reconstruction); 2) preprocessing (segmentation & quantization); 3) quantification (texture matrix design & texture feature extraction); and 4) analysis (statistics and/or machine learning). The parameters or conditions at each of these steps are effect on the results. In statistical testing or modeling, problems such as multiple comparisons, dependence on other variables, and high dimensionality of small sample size data should be considered. Standardization of methodology and harmonization of image quality are one of the most important challenges with radiomics methodology. Even though there are current issues in radiomics methodology, it is expected that radiomics will be clinically useful in personalized medicine for oncology.

Autoclustering of Non-small Cell Lung Carcinoma Subtypes on 18F-FDG PET Using Texture Analysis: A Preliminary Result

하승균,최홍윤,천기정,강건욱,정준기,김의신,이동수 대한핵의학회 2014 핵의학 분자영상 Vol.48 No.4

Purpose: Texture analysis on 18F-fluorodeoxyglucose positronemission tomography (18F-FDG PET) scan is a relativelynew imaging analysis tool to evaluate metabolic heterogeneity. We analyzed the difference in textural characteristicsbetween non-small cell lung carcinoma (NSCLC) subtypes,namely adenocarcinoma (ADC) and squamous cell carcinoma(SqCC). Methods: Diagnostic 18F-FDG PET/computed tomography(CT) scans of 30y patients (median age, 67; range, 42-88)with NSCLC (17 ADC and 13 SqCC) were retrospectivelyanalyzed. Regions of interest were manually determined onselected transverse image containing the highest SUV value intumors. Texture parameters were extracted by histogrambasedalgorithms, absolute gradient-based algorithms, runlengthmatrix-based algorithms, co-occurrence matrix-basedalgorithms, and autoregressive model-based algorithms. Twenty-four out of hundreds of texture features were selectedby three algorithms: Fisher coefficient, minimization of bothclassification error probability and average correlation, andmutual information. Automated clustering of tumors wasbased on the most discriminating feature calculated by lineardiscriminant analysis (LDA). Each tumor subtype was determinedby histopathologic examination after biopsy andsurgery. Results: Fifteen texture features had significant differentvalues between ADC and SqCC. LDA with 24 automateselectedtexture features accurately clustered between ADCand SqCC with 0.90 linear separability. There was no highcorrelation between SUVmax and texture parameters (|r|≤0.62). Conclusion Each subtype of NSCLC tumor has differentmetabolic heterogeneity. The results of this study support thepotential of textural parameters on FDG PET as an imagingbiomarker.

Clinical Outcome of Remnant Thyroid Ablation with Low Dose Radioiodine in Korean Patients with Low to Intermediate-risk Thyroid Cancer

하승균,오소원,김유경,구도훈,정윤호,이가희,정준기 대한의학회 2015 Journal of Korean medical science Vol.30 No.7

Radioiodine activity required for remnant thyroid ablation is of great concern, to avoid unnecessary exposure to radiation and minimize adverse effects. We investigated clinical outcomes of remnant thyroid ablation with a low radioiodine activity in Korean patients with low to intermediate-risk thyroid cancer. For remnant thyroid ablation, 176 patients received radioiodine of 1.1 GBq, under a standard thyroid hormone withdrawal and a low iodine diet protocol. Serum levels of thyroid stimulating hormone stimulated thyroglobulin (off-Tg) and thyroglobulin-antibody (Tg-Ab), and a post-therapy whole body scan (RxWBS) were evaluated. Completion of remnant ablation was considered when there was no visible uptake on RxWBS and undetectable off-Tg (<1.0 ng/mL). Various factors including age, off-Tg, and histopathology were analyzed to predict ablation success rates. Of 176 patients, 68.8% (n = 121) who achieved successful remnant ablation were classified into Group A, and the remaining 55 were classified into Group B. Group A presented with significantly lower off-Tg at the first radioiodine administration (pre-ablative Tg) than those of Group B (1.2 ± 2.3 ng/mL vs. 6.2 ± 15.2 ng/mL, P = 0.027). Pre-ablative Tg was the only significant factor related with ablation success rates. Diagnostic performances of pre-ablative Tg < 10.0 ng/mL were sensitivity of 99.1%, specificity of 14.0%, positive predictive value of 71.1%, and negative predictive value of 87.5%, respectively. Single administration of low radioiodine activity could be sufficient for remnant thyroid ablation in patients with low to intermediate-risk thyroid cancer. Pre-ablative Tg with cutoff value of 10.0 ng/mL is a promising factor to predict successful remnant ablation.

Perspectives in Radiomics for Personalized Medicine and Theranostics

하승균 대한핵의학회 2019 핵의학 분자영상 Vol.53 No.3

Radiomics handles imaging biomarker from high-throughput feature extraction through complex pattern recognition that is difficult for human to process. Recent medical paradigms are rapidly changing to personalized medicine, including molecular targeted therapy, immunotherapy, and theranostics, and the importance of biomarkers for these is growing day by day. Even though biopsy continues to gold standard for tumor assessment in personalized medicine, imaging is expected to complement biopsy because it allows whole tumor evaluation, whole body evaluation, and non-invasive and repetitive evaluation. Radiomics is known as a useful method to get imaging biomarkers related to intratumor heterogeneity in molecular targeted therapy as well as one-size-fits-all therapy. It is also expected to be useful in new paradigms such as immunotherapy and somatostatin receptor (SSTR) or prostate-specific membrane antigen (PSMA)-targeted theranostics. Radiomics research should move to multimodality (CT, MR, PET, etc.), multicenter, and prospective studies from current single modality, single institution, and retrospective studies. Image-quality harmonization, intertumor heterogeneity, and integrative analysis of information from different scales are thought to be important keywords in future radiomics research. It is clear that radiomics will play an important role in personalized medicine.

Relationship of EGFR Mutation to Glucose Metabolic Activity and Asphericity of Metabolic Tumor Volume in Lung Adenocarcinoma

위원석,하승균,배성우,최홍윤,팽진철,천기정,강건욱,이동수 대한핵의학회 2020 핵의학 분자영상 Vol.54 No.4

Purpose EGFR-mutation (EGFR-mt) is a major oncogenic driver mutation in lung adenocarcinoma (ADC) and is more often observed in Asian population. In lung ADC, some radiomics parameters of FDG PET have been reported to be associated with EGFR-mt. Here, the associations between EGFR-mt and PET parameters, particularly asphericity (ASP), were evaluated in Asian population. Methods Lung ADC patients who underwent curative surgical resection as the first treatment were retrospectively enrolled. EGFR mutation was defined as exon 19 deletion and exon 21 point mutation and was evaluated using surgical specimens. On FDG PET, image parameters of maximal standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and ASP were obtained. The parameters were compared between EGFR-mt and wild type (EGFR-wt) groups, and the relationships between these PET parameters and EGFR-mt were evaluated. Results A total of 64 patients (median age 66 years, M:F = 34:30) were included in the analysis, and 29 (45%) patients showed EGFR-mt. In EGFR-mt group, all the image parameters of SUVmax, MTV, TLG, and ASP were significantly lower than in EGFR-wt group (all adjusted P < 0.050). In univariable logistic regression, SUVmax (P = 0.003) and ASP (P = 0.010) were significant determinants for EGFR-mt, whereasMTV was not (P = 0.690). Multivariate analysis revealed that SUVmax and ASP are independent determinants for EGFR-mt, regardless of inclusion of MTV in the analysis (P < 0.05). Conclusion In Asian NSCLC/ADC patients, SUVmax, MTV, and ASP on FDG PET are significantly related to EGFR mutation status. Particularly, low SUVmax and ASP are independent determinants for EGFR-mt.

Comparison of Two Different Segmentation Methods on Planar Lung Perfusion Scan with Reference to Quantitative Value on SPECT/CT

서민석,강연구,하승균,김용일,팽진철,천기정,박사미나,김영태,이동수,E. Edmund Kim,정준기 대한핵의학회 2017 핵의학 분자영상 Vol.51 No.2

Purpose Until now, there was no single standardized regionalsegmentation method of planar lung perfusion scan.We comparedplanar scan based two segmentation methods, which arefrequently used in the Society of Nuclear Medicine, with referenceto the lung perfusion single photon emission computedtomography (SPECT)/computed tomography (CT) derivedvalues in lung cancer patients. Methods Fifty-five lung cancer patients (male:female, 37:18;age, 67.8 ± 10.7 years) were evaluated. The patientsunderwent planar scan and SPECT/CT after injection oftechnetium-99 m macroaggregated albumin (Tc-99 m-MAA). The % uptake and predicted postoperative percentageforced expiratory volume in 1 s (ppoFEV1%) derived fromboth posterior oblique (PO) and anterior posterior (AP)methods were compared with SPECT/CT derived parameters. Concordance analysis, paired comparison, reproducibilityanalysis and spearman correlation analysis were conducted. Results The % uptake derived from PO method showedhigher concordance with SPECT/CT derived % uptake in everylobe compared to AP method. Both methods showed significantlydifferent lobar distribution of%uptake compared toSPECT/CT. For the target region, ppoFEV1% measured fromPO method showed higher concordance with SPECT/CT, butlower reproducibility compared to AP method. Preliminarydata revealed that every method significantly correlated withactual postoperative FEV1%, with SPECT/CT showing thebest correlation. Conclusion The PO method derived values showed betterconcordance with SPECT/CT compared to the AP method. Both PO and AP methods showed significantly different lobardistribution compared to SPECT/CT. In clinical practice suchdifference according to different methods and lobes should beconsidered for more accurate postoperative lung functionprediction.

Prognostic value of preoperative intratumoral FDG uptake heterogeneity in early stage uterine cervical cancer

정현훈,강서영,하승균,김재원,박노현,송용상,천기정 대한부인종양학회 2016 Journal of Gynecologic Oncology Vol.27 No.2

Objective: We investigated the prognostic value of intratumoral [18F]fluorodeoxyglucose (FDG) uptake heterogeneity (IFH) derived from positron emission tomography/computed tomography (PET/CT) in patients with cervical cancer. Methods : Patients with uterine cervical cancer of the International Federation of Obstetrics and Gynecology (FIGO) stage IB to IIA were imaged with [18F]FDG PET/CT before radical surgery. PET/CT parameters such as maximum and average standardized uptake values (SUVmax and SUVavg), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and IFH were assessed. Regression analyses were used to identify clinicopathological and imaging variables associated with progression-free survival (PFS). Results : We retrospectively reviewed clinical data of 85 eligible patients. Median PFS was 32 months (range, 6 to 83 months), with recurrence observed in 14 patients (16.5%). IFH at an SUV of 2.0 was correlated with primary tumor size (p<0.001), SUVtumor (p<0.001), MTVtumor (p<0.001), TLGtumor (p<0.001), depth of cervical invasion (p<0.001), and negatively correlated with age (p=0.036). Tumor recurrence was significantly associated with TLGtumor (p<0.001), MTVtumor (p=0.001), SUVLN (p=0.004), IFH (p=0.005), SUVtumor (p=0.015), and FIGO stage (p=0.015). Multivariate analysis identified that IFH (p=0.028; hazard ratio, 756.997; 95% CI, 2.047 to 279,923.191) was the only independent risk factor for recurrence. The Kaplan-Meier survival graphs showed that PFS significantly differed in groups categorized based on IFH (p=0.013, log-rank test). Conclusion : Preoperative IFH was significantly associated with cervical cancer recurrence. [18F]FDG based heterogeneity may be a useful and potential predicator of patient recurrence before treatment.

Photo-Guided Sentinel Node Mapping in Breast Cancer Using Marker-Free Photo-Gamma Fusion Lymphoscintigraphy

이은성,천인국,하승균,윤혜전,정소연,이시연,김석원,이은숙,김태윤,김광기,이병일,김태성,김석기 대한핵의학회 2013 핵의학 분자영상 Vol.47 No.1

Purpose Photo-gamma fusion lymphoscintigraphy (PGFLS)was developed by overlying a conventional planar gamma image on a photograph for the guidance of sentinel node biopsy. The feasibility and accuracy of PGFLS was assessed in breast cancer patients. Methods A digital camera and a gamma camera were coordinated to obtain photograph and gamma images from the same angle. Using the distance to the object and calibration acquisition with a flat phantom and radioactive markers, PGFLS was performed both in phantom and in patients without fiducial markers. Marker-free PGFLS was verified using flat phantom, anthropomorphic phantom with markers simulating sentinel nodes and breast cancer patients. In addition, the depth of the radioactive marker or sentinel node was calculated using two gamma images taken at right angles. The feasibility and accuracy of PGFLS were assessed in terms of mismatch errors of co-registration and depth with reference to the data from SPECT/CT. Results The mismatch error was less than 6 mm in the flat phantom image at a distance from 50 to 62 cm without misalignment. In the anthropomorphic phantom study,co-registration error was 0.42±0.29 cm; depth error was 0.51±0.37 cm, which was well correlated with the reference value on SPECT/CT (x scale: R200.99, p<0.01; y scale: R200.99, p<0.01; depth: R200.99, p<0.01). In ten patients with breast cancer referred for lympho-SPECT/CT, PGFSL enabled photo-guided sentinel lymph node mapping with acceptable accuracy (co-registration error,0.47±0.24 cm; depth error, 1.20 ±0.41 cm). The results from PGFSL showed close correlation with those from SPECT/CT (x scale: R200.99, p<0.01; y scale: R200.98,p<0.01; depth: R200.77, p<0.01). Conclusions The novel and convenient PGFLS technique is clinically feasible, showing acceptable accuracy and providing additional visual and quantitative information for sentinel lymph node mapping. This approach will facilitate photo-guided sentinel lymph node dissection in breast cancer.

Tc-99m Hydroxymethylene Diphosphonate (HMDP) Renal Uptake as a Surrogate Marker of Postoperative Impairment of the Glomerular Filtration Rate in Renal Tumor Patients Following Nephron-Sparing Surgery

최홍윤,이원우,소영,하승균,변석수,김상은 대한핵의학회 2014 핵의학 분자영상 Vol.48 No.4

P u r p o s e : We i n v e s t i g a t ed Tc - 9 9mhydroxymethylene diphosphonate (HMDP) scintigraphy findingsin renal tumor patients from the perspective of postoperativerenal dysfunction following nephron-sparing surgery(NSS). Methods: Forty-three renal tumor patients (M:F =28:15, age 53.9±12.5 years) who had undergone Tc-99mHMDP scintigraphy after NSS were enrolled. The patientswere divided into HMDP+ or HMDP− groups by visual assessment,and the asymmetric index (ASI) was calculatedusing a region-of-interest analysis. In 16 patients, the totaland split glomerular filtration rate (GFR) was assessed usingTc-99m diethylenetriaminepentaacetic acid (DTPA) scintigraphyat baseline and at 3 and 6months post-NSS. Results: HighTc-99m HMDP uptake was observed in the operated kidneys,but this did not persist later than 7 days post-NSS. Split GFRof the operated kidneys at baseline (58.5±9.3 ml/min) wassignificantly reduced at 6 months post-NSS (40.1±5.9 ml/min, p<0.001) in only those who showed intense uptake ofTc-99m HMDP. Declines in both total GFR (p=0.010 and p=0.002 for 3 and 6 months, respectively) and split GFR of theoperated kidneys (p<0.001 and p<0.001 for 3 and 6 months,respectively) were clearly evidenced at 3 and 6 months post-NSS only in patients with high Tc-99m HMDP in the operatedkidneys. The ASI was negatively correlated with %change inthe split GFR of these operated kidneys at 6 months post-NSS(rho =−0.578, p=0.0304). Conclusions: Tc-99m HMDP uptakewithin 1 week following NSS is a surrogate marker ofGFR impairment over 6 months post-NSS.