Hye Ok Kim

Subregional Patterns of Preferential Striatal Dopamine Transporter Loss Differ in Parkinson Disease, Progressive Supranuclear Palsy, and Multiple-System Atrophy

Parkinson disease (PD), progressive supranuclear palsy (PSP), and multiple-system atrophy (MSA) are known to affect dopaminergic neurons of the brain stem and striatum with different preferential involvement. Here we investigated differences in striatal subregional dopamine transporter loss in PD, PSP, and MSA and assessed the diagnostic value of 18F-fluorinated-N-3-fluoropropyl-2-β-carboxymethoxy-3-β-(4-iodophenyl)nortropane (18F-FP-CIT) PET in differentiating PSP and MSA from PD. Methods: Forty-nine patients with PD, 19 patients with PSP, 24 patients with MSA, and 21 healthy people (healthy controls) were examined with 18F-FP-CIT PET. The PET images were spatially normalized and analyzed with 12 striatal subregional volume-of-interest (VOI) templates (bilateral ventral striatum [VS], anterior caudate [AC], posterior caudate, anterior putamen, posterior putamen [PP], and ventral putamen [VP]) and 1 occipital VOI template. The nondisplaceable binding potential (BPND) and intersubregional ratio (ISR; defined as the ratio of the BPND of one striatal subregion to that of another striatal subregion) of subregional VOIs were calculated. Results: The BPND of all VOIs in the PD, MSA, and PSP groups were significantly lower than those in the healthy controls (P < 0.05). The BPND of AC and the AC/VS ISR in the PSP group were significantly lower than those in the PD group. The BPND of VP was significantly lower, but the PP/VP ISR was significantly higher in the MSA group than in the PD group. At the cutoff value for the AC/VS ISR (<0.7), the sensitivity and specificity for differentiating PSP from PD were 94% and 92%, respectively. At the cutoff value for the PP/VP ISR (>0.65), the sensitivity and specificity for differentiating MSA from PD were 90% and 45%, respectively. The diagnostic accuracy of visual analysis was similar to that of quantitative analysis for differentiating PSP from PD but was significantly higher for differentiating MSA from PD. Conclusion: Compared with PD, PSP and MSA showed more prominent and earlier dopamine transporter loss in the AC and VP, respectively. These findings could be useful for suggesting PSP or MSA in parkinsonian cases without characteristic atypical features.

Evaluation of disease activity using F-18 FDG PET-CT in patients with Takayasu arteritis.

Purpose of the Report: To evaluate the usefulness of F-18 fluoro-fluorodeoxygulose positron emission tomography computed tomography (F-18 FDG PET-CT) in detecting clinically defined active disease in patients with Takayasu arteritis. Methods: F-18 FDG PET-CT was performed in 32 patients with Takayasu arteritis. Disease activity was assessed clinically by the National Institutes of Health (NIH) criteria. In 10 of the 32 patients, F-18 FDG PET-CT was performed while the patients were taking immunosuppressive drugs. Two nuclear physicians visually assessed the degree of F-18 FDG uptake in the walls of the aorta, its major branches and the pulmonary artery using a 4-point scale from grade 0 to III. F-18 FDG uptake greater than grade I in the thoracic aorta or greater than grade 0 in other areas were interpreted as active vasculitic lesions. Results: Ten patients had active lesions on F-18 FDG PET-CT. According to the NIH criteria, 9 patients had active disease and 23 had inactive disease. Compared with disease activity assessed by the NIH criteria, F-18 FDG PET-CT had a sensitivity of 78% and a specificity of 87%. The erythrocyte sedimentation rate and CRP levels were significantly higher in F-18 FDG PET-CT-positive than in F-18 FDG PET-CT-negative patients. There was no significant difference in the proportion of positive PET scans according to the use of glucocorticoids. Conclusions: The sensitivity of F-18 FDG PET-CT for detecting active disease was higher in patients with higher erythrocyte sedimentation rate values. Although the specificity of F-18 FDG PET-CT was high, owing to the low sensitivity of the NIH criteria in detecting active disease, further studies are needed.

Prognostic Value of Metabolic Parameters in Patients with Synchronous Colorectal Cancer Liver Metastasis Following Curative-Intent Colorectal and Hepatic Surgery

Synchronous colorectal cancer liver metastasis (SCLM) remains a clinical challenge, largely because of the limited availability of tools that use reliable prognostic indicators to guide treatment. This study assessed the prognostic ability of preoperative 18F-FDG PET/CT in patients with SCLM who had undergone curative-intent colorectal and liver surgery. Methods: All included patients had undergone simultaneous colorectal and hepatic surgery to treat SCLM. Cox regression for survival analysis was undertaken using clinicopathologic variables and metabolic parameters (metabolic tumor volume [MTV], total lesion glycolysis [TLG], and peak standardized uptake value [SUVpeak]) as covariates, with tumor recurrence and death used as endpoints. Results: One hundred twenty patients (82 men, 38 women; mean age ± SD, 59.9 ± 10.1 y) met the inclusion and exclusion criteria. Univariate analysis showed that MTV, TLG, and the size of hepatic metastases were significant indicators of both recurrence-free survival and overall survival, whereas those of primary colorectal tumors were not. Multivariate analysis revealed that the SUVpeak of primary tumors and hepatic metastases remained significant after adjusting for other clinicopathologic variables, whereas the MTV and TLG of hepatic metastases became insignificant after adjusting for differences in tumor size. The combination of a high SUVpeak of hepatic metastases and a low SUVpeak of primary tumors was related to poor prognosis under the multivariate model. Conclusion: In patients with SCLM who underwent curative-intent colorectal and liver surgery, metabolic parameters of hepatic metastases possess prognostic significance whereas those of primary colorectal tumors do not. For hepatic metastases, the SUVpeak is an independent prognostic factor, whereas MTV and TLG are surrogate measures of tumor size. Reduced recurrence-free survival rates are associated with higher SUVpeak for hepatic metastases and lower SUVpeak for primary tumors. Further studies are needed to elucidate the underlying mechanisms.

Evaluation of Metabolic Characteristics and Viability of Lipiodolized Hepatocellular Carcinomas Using 18F-FDG PET/CT

This study aimed to evaluate the metabolic characteristics of lipiodolized hepatocellular carcinomas (HCCs) and the diagnostic accuracy of 18F-FDG PET/CT in assessing the viability of lipiodolized HCCs. Methods: Thirty-six patients (age range, 32–73 y) with 38 lipiodolized HCCs who had undergone transcatheter arterial chemoembolization (TACE) with lipiodol before 18F-FDG PET/CT (2–434 d) and 55 patients (age range, 36–77 y) with 57 treatment-naïve HCCs who had not been treated with TACE were retrospectively studied. All patients underwent hepatic lobectomy or transplantation within 1 mo after PET/CT and multiphasic contrast-enhanced CT. 18F-FDG uptake by lipiodolized and naïve HCCs was compared and correlated with tumor size, pathologic grade, serum α-fetoprotein (AFP) concentration, and time interval between TACE and PET/CT. The diagnostic accuracy of PET/CT and contrast-enhanced CT in evaluating the viability of lipiodolized HCC was compared. Results: Histologic examination showed 30 viable and 8 nonviable lipiodolized HCCs. Of the 30 viable tumors, 19 showed increased, 10 similar, and 1 decreased 18F-FDG uptake. Of the 8 nonviable HCCs, 3 showed increased and 5 decreased 18F-FDG uptake. Uptake by viable lipiodolized HCCs was correlated with tumor size (P < 0.05) but not correlated with pathologic grade, AFP concentration, or interval between TACE and PET/CT. In contrast, 18F-FDG uptake by naïve HCCs was significantly correlated with tumor size and pathologic grade (P < 0.05 for each comparison). When lipiodolized HCCs with 18F-FDG uptake that was greater than or similar to that in the surrounding normal liver were considered viable, the diagnostic sensitivity of PET/CT and contrast-enhanced CT in the early postembolic period (<3 mo) was 100% and 94%, respectively, and that in the late postembolic period was 93% and 79%, respectively. The specificity of 18F-FDG PET/CT and contrast-enhanced CT was 63% and 100%, respectively, in the acute period. Three viable lipiodolized HCCs with high AFP concentration were true-positives on PET/CT but false-negatives on contrast-enhanced CT images. Conclusion: After TACE, 18F-FDG uptake in lipiodolized HCCs was not correlated with pathologic grade, in contrast to uptake in treatment-naïve HCCs. 18F-FDG PET/CT showed a high diagnostic sensitivity in assessing the viability of lipiodolized HCCs, with moderate specificity. This method may be useful in determining the viability of lipiodolized HCCs in patients with increased serum AFP concentration or normal results on contrast-enhanced CT images.

18F-Fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography in mucosa-associated lymphoid tissue lymphoma: variation in 18F-FDG avidity according to site involvement

The purpose of this study was to determine the 18F-FDG avidity of MALT lymphoma and the additional utility of 18F-FDG PET/CT in MALT lymphoma staging. Pretreatment 18F-FDG PET/CT scans of 222 patients with 227 MALT lymphoma lesions were retrospectively analyzed. 18F-FDG avidity of lesions was noted in 28%. The proportion was lower for gastric MALT lymphomas than for non-gastric lesions (9% vs. 60%, p < 0.0001) and higher for mass-forming lesions than for superficial lesions (82% vs. 2%, p < 0.0001). 18F-FDG PET/CT showed the presence of additional lesions in 23 patients: four of six true-positive lesions had 18F-FDG avid primary lesions, and 15 of 17 false-positive lesions had 18F-FDG-non avid lesions. 18F-FDG avidity differed according to the location and gross morphologic characteristics of the MALT lymphoma. Most gastric MALT lymphomas were superficial and had low 18F-FDG avidity. For staging, 18F-FDG PET/CT can be helpful mainly for 18F-FDG avid primary MALT lymphomas.

Usefulness of adding SPECT/CT to 99mTc-hexamethylpropylene amine oxime (HMPAO)-labeled leukocyte imaging for diagnosing prosthetic joint infections.

Objective This study evaluated the usefulness of adding single-photon emission computed tomography (SPECT)/computed tomography (CT) (SPECT/CT) to technetium Tc 99m (99mTc) hexamethylpropylene amine oxime (HMPAO)-labeled leukocyte imaging for diagnosing infections in hip or knee joint prostheses. Methods The 99mTc-HMPAO-labeled leukocyte scans of 164 patients (71 with hip prostheses and 93 with knee prostheses) with clinically suspected prosthetic infections were reviewed retrospectively. Planar images were taken 4 to 6 and 21 to 26 hours after injecting the labeled leukocytes and SPECT/CT images were obtained 4 to 6 hours after the injection. The final diagnosis of infection was based on pathologic findings (n = 70), bacteriological data (n = 61), or clinical follow-up (n = 33). Results Of the 164 patients, 89 patients had a diagnosis of prosthetic joint infections. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of the planar images alone were 82.0%, 88.0%, 89.0%, 80.5%, and 84.8%, respectively. When the planar images were combined with SPECT, the sensitivity, specificity, PPV, NPV, and diagnostic accuracy were 91.0%, 88.0%, 90.0%, 89.2%, and 89.6%, respectively. When the planar images were combined with SPECT/CT, these values increased further to 93.3%, 93.3%, 94.3%, 92.1%, and 93.3%, respectively. Adding CT to SPECT resulted in a greater increase in sensitivity and specificity for hip prosthesis infections than for knee prosthesis infections. SPECT/CT mainly contributed by precisely localizing the anatomical site of the active inflammatory lesion and by delineating the extent of the lesion after diagnosis with SPECT. Conclusions Single-photon emission computed tomography/CT combined with 99mTc-HMPAO-labeled leukocyte imaging was useful for diagnosing prosthesis infections, particularly in hip prosthesis infections, as it improved diagnostic accuracy and provided anatomical localization data.

18F‐fluorodeoxyglucose uptake predicts pathological complete response after neoadjuvant chemotherapy for breast cancer: A retrospective cohort study

18F‐fluorodeoxyglucose (18F‐FDG) uptake may identify poorly differentiated tumors with a high proliferation rate that are more responsive to neoadjuvant chemotherapy.

A randomized feasibility study of 18F-fluoroestradiol positron emission tomography to predict pathological response to neoadjuvant systemic therapy in estrogen receptor-rich postmenopausal breast cancer

The aim of this study was to explore the ability of 18F-fluoroestradiol (18F-FES) PET/CT imaging to predict pathologic response to neoadjuvant therapy in postmenopausal women with estrogen receptor (ER)–rich breast cancer. Methods: This was a prospective, single-center study conducted as a substudy of the neoadjuvant study of chemotherapy versus endocrine therapy in postmenopausal patients with primary breast cancer (NEOCENT) trial. Patients with ER-rich breast cancer were randomized to neoadjuvant chemotherapy (NC) or neoadjuvant endocrine therapy (NET). The baseline SUVmax of 18F-FES PET/CT was measured. The pathologic response was assessed by the Miller–Payne system as nonresponse (grades 1 and 2) and response (grades 3–5). Results: Twenty-six patients were enrolled, with pathologic response achieved in 25 (NC, 12; NET, 13). Two patients achieved pathologic complete response after NC, but the remaining 23 patients had residual disease after NC or NET. Eight of 12 patients responded to NC, and 4 of 13 to NET; the difference was marginally significant (P = 0.07). In the NC group, the 2 patients with 18F-FES–negative tumors and none of the 10 patients with 18F-FES–avid tumors achieved pathologic complete response (P = 0.02). No difference in the SUVmax between responders and nonresponders was observed in either group. However, 5 of 7 NC patients with a baseline SUVmax of less than 7.3 achieved pathologic response, whereas none of the 5 NET patients with an SUVmax of less than 7.3 were responders (P = 0.03). The SUVmax values of the NC group were negatively correlated with percentage reduction of tumor cellularity (r = −0.63, P = 0.03), whereas those of the NET group showed positive correlation (r = 0.62, P = 0.02). During the median follow-up of 74 mo (range, 44–85 mo), recurrence occurred in only 4 NET patients. In patients with an SUVmax of less than 7.3, recurrence occurred in none of the 8 NC patients and 2 of the 5 NET patients (P = 0.13). Conclusion: Postmenopausal women who are ER-positive, but 18F-FES–negative, may benefit from NC rather than NET. 18F-FES PET/CT has the potential to predict response to neoadjuvant therapy in postmenopausal women with ER-rich breast cancer.

The role of integrated 18F-FDG PET-CT as a staging tool for limited-stage small cell lung cancer: a retrospective study.

Background: The aim of this study was to evaluate whether positron emission tomography-computed tomography (PET-CT) could be used as part of the staging work-up in patients with limited-stage disease (LD) small cell lung cancer (SCLC). Patients and Methods: Between January 2002 and December 2007, a total of 73 patients with presumed LD on CT, who underwent a PET-CT scan, were included in this study. Results: Conventional work-up revealed distant metastases in 12 patients. Out of 61 patients diagnosed as LD SCLC, PET-CT found unexpected distant metastases in 15 (24.6%) patients (LD/extensive-stage disease (ED)) of whom 13 (21.3%) were upstaged as a consequence. In 10 (76.9%) of the 13 upstaged patients, treatment was changed. The median survival of LD/LD SCLC patients who underwent concurrent chemoradiotherapy and chemotherapy only was 21.9 and 17.5 months, respectively. The median survival of LD/ED and ED/ED SCLC patients who received chemotherapy only was 17.4 and 14.1 months, respectively. The median survival of LD/LD SCLC patients who received concurrent chemoradiotherapy was superior to that of LD/ ED and ED/ED patients who received chemotherapy only (p = 0.037 and 0.004, respectively). Conclusion: The addition of PET-CT seems to allow more accurate staging and may thus protect a percentage of SCLC patients from potentially futile and toxic radiotherapy.

Evaluation of selective positron emission tomography template method for spatial normalization of amyloid imaging with 11C-Pittsburgh Compound B.

Objective Spatial normalization of 11C-Pittsburgh Compound B (PiB) images is challenging for an automatic quantitative analysis without magnetic resonance imaging (MRI) because of different distribution patterns between amyloid positive and negative images. To overcome this issue, we evaluated a selective positron emission tomography template (SPT) method. Materials and Methods Three sets of single positron emission tomography templates were created: PiB negative template, PiB positive template, and mixed template. Sixty-one patients with dementia were enrolled as the validation cohort. Magnetic resonance imaging–aided normalization method was used as a reference. The SPT method was based on visual classification (positive, negative, and equivocal). The optimal templates for each visual group were determined by correlation values and average percent errors (APEs) with MRI-aided normalization. The results of the SPT and the single template methods were compared with those of MRI-aided normalization in terms of correlation values, APEs, and concordance rates. Results The SPT (PiB negative template for the negative and equivocal groups and PiB positive template for the positive group) showed higher correlations and concordance rate and lower APEs with MRI-aided normalization than did the single template. Conclusions Use of the SPT provides accurate normalization of amyloid images without MRI.