Spatial Normalization Using Early-Phase 18FFP-CIT PET for Quantification of Striatal Dopamine Transporter Binding / 대한핵의학회잡지

Purpose@#The precise quantification of dopamine transporter (DAT) density on N-(3-[18F]Fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl) nortropane positron emission tomography ([18F]FP-CIT PET) imaging is crucial to measure the degree of striatal DAT loss in patients with parkinsonism. The quantitative analysis requires a spatial normalization process based on a template brain. Since the spatial normalization method based on a delayed-phase PET has limited performance, we suggest an early-phase PET-based method and compared its accuracy, referring to the MRI-based approach as a gold standard. @*Methods@#A total of 39 referred patients from the movement disorder clinic who underwent dual-phase [18F]FP-CIT PET and took MRI within 1 year were retrospectively analyzed. The three spatial normalization methods were applied for quantification of [18F]FP-CIT PET-MRI-based anatomical normalization, PET template-based method based on delayed PET, and that based on early PET. The striatal binding ratios (BRs) were compared, and voxelwise paired t tests were implemented between different methods. @*Results@#The early image-based normalization showed concordant patterns of putaminal [18F]FP-CIT binding with an MRI-based method. The BRs of the putamen from the MRI-based approach showed higher agreement with early image- than delayed image-based method as presented by Bland-Altman plots and intraclass correlation coefficients (early image-based, 0.980; delayed image-based, 0.895). The voxelwise test exhibited a smaller volume of significantly different counts in putamen between brains processed by early image and MRI compared to that between delayed image and MRI. @*Conclusion@#The early-phase [18F]FP-CIT PET can be utilized for spatial normalization of delayed PET image when the MRI image is unavailable and presents better performance than the delayed template-based method in quantitation of putaminal binding ratio.

Relationship of EGFR Mutation to Glucose Metabolic Activityand Asphericity of Metabolic Tumor Volumein Lung Adenocarcinoma / 대한핵의학회잡지

Purpose@#EGFR-mutation (EGFR-mt) is a major oncogenic driver mutation in lung adenocarcinoma (ADC) and is more oftenobserved in Asian population. In lung ADC, some radiomics parameters of FDG PET have been reported to be associated withEGFR-mt. Here, the associations between EGFR-mt and PET parameters, particularly asphericity (ASP), were evaluated inAsian 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. OnFDG PET, image parameters of maximal standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesionglycolysis (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 showedEGFR-mt. In EGFR-mt group, all the image parameters of SUVmax, MTV, TLG, and ASP were significantly lower than inEGFR-wt group (all adjusted P< 0.050). In univariable logistic regression, SUVmax (P= 0.003) and ASP (P= 0.010) weresignificant determinants for EGFR-mt, whereasMTV was not (P= 0.690). Multivariate analysis revealed that SUVmax and ASPare 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 mutationstatus. Particularly, low SUVmax and ASP are independent determinants for EGFR-mt.

Quantitative Single-Photon Emission Computed Tomography/Computed Tomography for Evaluation of Salivary Gland Dysfunction in Sjögren's Syndrome Patients / 대한핵의학회잡지

PURPOSE: The purpose of the study was to investigate the usefulness of quantitative salivary single-photon emission computed tomography/computed tomography (SPECT/CT) using Tc-99m pertechnetate in Sjögren's syndrome (SS).METHODS: We retrospectively reviewed quantitative salivary SPECT/CT data from 95 xerostomic patients who were classified as either SS (n = 47, male:female = 0:47, age = 54.60 ± 13.16 y [mean ± SD]) or non-SS (n = 48, male:female = 5:43, age = 54.94 ± 14.04 y) by combination of anti-SSA/Ro antibody, labial salivary gland biopsy, unstimulated whole saliva flow rate, and Schirmer's test. Thyroid cancer patients (n = 43, male:female = 19:24, age = 46.37 ± 12.13 y) before radioactive iodine therapy served as negative controls. Quantitative SPECT/CT was performed pre-stimulatory 20 min and post-stimulatory 40 min after injection of Tc-99m pertechnetate (15 mCi). The %injected dose at 20 min and the %excretion between 20 and 40 min were calculated for parotid and submandibular glands, generating four quantitative parameters: %parotid uptake (%PU), %submandibular uptake (%SU), %parotid excretion (%PE), and %submandibular excretion (%SE). The most useful parameter for SS diagnosis was investigated.RESULTS: The uptake parameters (%PU and %SU) were significantly different among the SS, non-SS, and negative controls (p = 0.005 for %PU and p < 0.001 for %SU, respectively), but the excretion parameters (%PE and %SE) were not (p > 0.05 for both). The%PU and%SU were significantly lower in SS than in the negative controls and non-SS (p < 0.05 for all pair-wise comparisons). Additionally, the %SU was significantly lower in non-SS than in the negative controls (p < 0.05). Receiver-operating characteristic analysis revealed that the %SU had the greatest area-under-the curve of 0.720 (95% confidence interval = 0.618–0.807). Using the optimal cut-off value of %SU ≤ 0.07%, SS was identified with a sensitivity of 70.21% and a specificity of 70.83%.CONCLUSION: Reduced submandibular uptake of Tc-99m pertechnetate at 20 min (%SU) was proved useful for the diagnosis of SS. Quantitative salivary gland SPECT/CT holds promise as an objective imaging modality for assessment of salivary dysfunction and may facilitate accurate classification of SS.

Usefulness of Respiratory-Gated ¹⁸F-FDG PET/CT in Detecting Upper Abdominal Fever Focus / 대한핵의학회잡지

Respiratory-gated ¹⁸F-fluorodeoxygluocse (¹⁸F-FDG) PET/CT has been successfully used to better localize malignancies in the lung or upper abdominal organs. However, clinical usefulness of respiratory-gated ¹⁸F-FDG PET/CT in detection of fever focus has not been reported yet. A 68-year-old male patient with a history of living donor liver transplantation and biliary stenting was referred for ¹⁸F-FDG PET/CT due to fever of unknown origin (FUO). To find the accurate fever focus, respiratory-gated and non-gated ¹⁸F-FDG PET/CT was performed. Respiratory-gated PET/CT readily revealed prominent hypermetabolic lesion in the distal common bile duct (CBD) area where previous surgical graft was in situ. Maximum standardized uptake value (SUVmax) and SUVratio (SUR) were greater in the gated PET/CT (SUVmax 5.4 and SUR 3.5) than in the non-gated PET/CT (SUVmax 4.6 and SUR 3.0). Fever dramatically subsided after removal of the graft in the CBD. This case report implies that respiratory-gated ¹⁸F-FDG PET/CT can visualize upper abdominal fever focus with better contrast than the conventional non-gated method.

Quantitative Single-Photon Emission Computed Tomography/Computed Tomography for Evaluation of Salivary Gland Dysfunction in Sjögren's Syndrome Patients / 대한핵의학회잡지

PURPOSE@#The purpose of the study was to investigate the usefulness of quantitative salivary single-photon emission computed tomography/computed tomography (SPECT/CT) using Tc-99m pertechnetate in Sjögren's syndrome (SS).@*METHODS@#We retrospectively reviewed quantitative salivary SPECT/CT data from 95 xerostomic patients who were classified as either SS (n = 47, male:female = 0:47, age = 54.60 ± 13.16 y [mean ± SD]) or non-SS (n = 48, male:female = 5:43, age = 54.94 ± 14.04 y) by combination of anti-SSA/Ro antibody, labial salivary gland biopsy, unstimulated whole saliva flow rate, and Schirmer's test. Thyroid cancer patients (n = 43, male:female = 19:24, age = 46.37 ± 12.13 y) before radioactive iodine therapy served as negative controls. Quantitative SPECT/CT was performed pre-stimulatory 20 min and post-stimulatory 40 min after injection of Tc-99m pertechnetate (15 mCi). The %injected dose at 20 min and the %excretion between 20 and 40 min were calculated for parotid and submandibular glands, generating four quantitative parameters: %parotid uptake (%PU), %submandibular uptake (%SU), %parotid excretion (%PE), and %submandibular excretion (%SE). The most useful parameter for SS diagnosis was investigated.@*RESULTS@#The uptake parameters (%PU and %SU) were significantly different among the SS, non-SS, and negative controls (p = 0.005 for %PU and p 0.05 for both). The%PU and%SU were significantly lower in SS than in the negative controls and non-SS (p < 0.05 for all pair-wise comparisons). Additionally, the %SU was significantly lower in non-SS than in the negative controls (p < 0.05). Receiver-operating characteristic analysis revealed that the %SU had the greatest area-under-the curve of 0.720 (95% confidence interval = 0.618–0.807). Using the optimal cut-off value of %SU ≤ 0.07%, SS was identified with a sensitivity of 70.21% and a specificity of 70.83%.@*CONCLUSION@#Reduced submandibular uptake of Tc-99m pertechnetate at 20 min (%SU) was proved useful for the diagnosis of SS. Quantitative salivary gland SPECT/CT holds promise as an objective imaging modality for assessment of salivary dysfunction and may facilitate accurate classification of SS.

Usefulness of Respiratory-Gated ¹⁸F-FDG PET/CT in Detecting Upper Abdominal Fever Focus / 대한핵의학회잡지

Respiratory-gated ¹⁸F-fluorodeoxygluocse (¹⁸F-FDG) PET/CT has been successfully used to better localize malignancies in the lung or upper abdominal organs. However, clinical usefulness of respiratory-gated ¹⁸F-FDG PET/CT in detection of fever focus has not been reported yet. A 68-year-old male patient with a history of living donor liver transplantation and biliary stenting was referred for ¹⁸F-FDG PET/CT due to fever of unknown origin (FUO). To find the accurate fever focus, respiratory-gated and non-gated ¹⁸F-FDG PET/CT was performed. Respiratory-gated PET/CT readily revealed prominent hypermetabolic lesion in the distal common bile duct (CBD) area where previous surgical graft was in situ. Maximum standardized uptake value (SUVmax) and SUVratio (SUR) were greater in the gated PET/CT (SUVmax 5.4 and SUR 3.5) than in the non-gated PET/CT (SUVmax 4.6 and SUR 3.0). Fever dramatically subsided after removal of the graft in the CBD. This case report implies that respiratory-gated ¹⁸F-FDG PET/CT can visualize upper abdominal fever focus with better contrast than the conventional non-gated method.

Gastrointestinal Stromal Tumor Accompanied with von Recklinghausen's Disease: Positive for CD117, CD34, SMA and S-100 Protein

Gastrointestinal stromal tumors (GISTs) are CD117-positive primary mesenchymal tumors of the gastrointestinal tract and they have a characteristic set of morphologic features. GISTs have been noted to have a possible non-random association with neurofibromatosis-1 (NF-1, von Recklinghausen disease). We report here on a case of multiple GISTs with abundant skenoid fiber in the jejunum of a 47-year-old woman, and this condition was accompanied with NF-1. The tumor cells coexpressed smooth muscle actin, S-100 protein, CD117 and CD34. These immunohistochemical results are extremely rare findings for GISTs accompanying with NF-1. We think this is the first report of GISTs arising within NF-1 with the dual immunohistochemical differentiation of neuronal and muscular markers.