Yonglin Pu

University of Chicago, Chicago, Illinois, United States

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Publications (57)179 Total impact

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    ABSTRACT: Patients <12 months with favorable biology, metastatic neuroblastoma have >90% overall survival following treatment with chemotherapy and surgery. We report two infants with favorable biology, stage 4 neuroblastoma with refractory disease after standard intermediate-risk chemotherapy and additional retrieval chemotherapy. One patient was treated with six additional cycles of isotretinoin and the other observed. Both remain clinically well with persistent disease but no evidence of tumor progression for 28 and 13 months following completion of cytotoxic treatment. Similar to residual tumor in primary sites, refractory metastatic disease may not portend a poor outcome in patients with favorable biology, intermediate-risk neuroblastoma. Pediatr Blood Cancer © 2013 Wiley Periodicals, Inc.
    Pediatric Blood & Cancer 11/2013; · 2.35 Impact Factor
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    ABSTRACT: Objective To assess the prognostic value of metabolic tumor burden as measured with metabolic tumor volume (MTV) and total lesion glycolysis (TLG) on 2-deoxy-2-(18F)fluoro-D-glucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT), independent of current Union Internacional Contra la Cancrum/American Joint Committee on Cancer tumor, node, and metastasis (TNM) stage; in comparison with that of standardized uptake value (SUV) in surgical patients with non–small-cell lung cancer (NSCLC). Material and Methods This study retrospectively reviewed 104 consecutive surgical patients (47 males, 57 females, median age at PET/CT scan of 67.92 years) with diagnosed stage I to IV NSCLC who had baseline 18F-FDG PET/CT scans. The 18F-FDG PET/CT scans were performed in accordance with National Cancer Institute guidelines. The MTV of tumors in the whole body (MTVWB), TLG of tumors in the whole body (TLGWB), the maximum standardized uptake value of tumors in the whole body (SUVmaxWB) as well as the mean standardized uptake value of tumor in the whole body (SUVmeanWB) were measured. The median follow-up among 67 survivors was 42.07 months from the PET/CT (range 2.82–80.95 months). Statistical methods included Kaplan-Meier curves, Cox regression, and C-statistics. The interobserver variability of SUVmaxWB, SUVmeanWB, MTVWB, and TLGWB between two observers was analyzed using concordance correlation coefficients (CCCs). Results The interobserver variability of SUVmaxWB, SUVmeanWB, MTVWB and TLGWB was very low with CCCs greater than 0.882. There was a statistically significant association of stage with overall survival (OS). The hazard ratio (HR) of stage III and stage IV as compared with stage I was 3.60 (P = .001) and 4.00 (P = .013), respectively. The MTVWB was significantly associated with OS with a HR for 1-unit increase of ln(MTVWB) of 1.40/1.32 (P = .004/.039), before/after adjusting for stage and other prognostic factors including chemoradiation therapy, and surgical procedure, respectively. TLGWB had a statistically significant association with OS before and after adjusting for stage and the other prognostic factors. The HR for 1-unit increase in ln(TLGWB) was 1.26 (P = .011) and 1.25 (P = .031), before and after the adjustment, respectively. Subjects with conditions that led to pneumonectomy (HR = 2.82, P = .035) or segmental resection (HR = 3.44, P = .044) had significantly worse survival than those needing lobectomy. There was no statistically significant association between OS and age, gender, tumor histology, ln(SUVmaxWB), and ln(SUVmeanWB) (all P > .05). There were 37 deaths during follow-up. Conclusion Baseline whole-body metabolic tumor burden as measured with MTVWB and TLGWB on FDG PET is a prognostic measure independent of clinical stage and other prognostic factors including chemoradiation therapy and surgical procedure with low interobserver variability and may be used to further risk stratify surgical patients with NSCLC. This study also suggests that MTV and TLG are better prognostic measures than SUVmax and SUVmean. These results will need to be validated in larger cohorts in a prospective study.
    Academic radiology 01/2013; 20(1):32–40. · 2.09 Impact Factor
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    ABSTRACT: PURPOSE Current evaluation of patients with suspected urinary tract obstruction is retrospective, and requires loss of progressive renal function for diagnosis. Furthermore, prospective studies such as diuretic renal scintigraphy (DRS) using half-time (T ½) of tracer clearance have shown low positive predictive value. The objective of this study is to assess the utility of renal pelvic appearance time (PAT) to diagnose ureteropelvic junction (UPJ) obstruction that would benefit from surgical intervention. METHOD AND MATERIALS An IRB-approved retrospective review was performed on 55 patients with clinically-suspected UPJ obstruction treated with pyeloplasty. Each patient had undergone a pre and post surgical DRS. The pre-surgical split kidney function (SKF), T ½ tracer clearance, and PAT were calculated on each patient. The ability of the PAT difference in seconds between the affected and contra-lateral kidneys in predicting improvement in post-surgical renal function was determined using the gold standard of split kidney function improvement > 5%. Area under the Receiver Operating Characteristic (ROC) curve (AUC) was used to assess the performance in distinguishing between patients with improved renal function and those without post surgery. The AUC of the PAT difference was compared with the T1/2 and SKF of the affected kidney. RESULTS Of the 55 patients who underwent pyeloplasty, 10 patients demonstrated a SKF improvement greater than 5% on the affected surgical side and 8 patients demonstrated a SKF decrease greater than 5%. AUC values for predicting improvement of renal function greater than 5% in the PAT difference between the affected and contra-lateral kidneys as well as the SKF and T ½ tracer clearance of the affected kidney were found to be 0.73 (SE=0.07), 0.68 (SE=0.09), and 0.63 (SE=0.14) respectively. AUC values for these same variables in predicting decline of SKF greater than 5% was found to be 0.74 (SE=0.11), 0.55 (SE=0.11), and 0.77 (SE=0.13) respectively. CONCLUSION This study shows the potential of PAT in patients with clinically suspected UPJ obstruction by predicting which patients would show improvement or decline in SKF following surgical pyeloplasty. CLINICAL RELEVANCE/APPLICATION PAT may help clinicians determine which patients with suspected UPJ obstruction will benefit from pyeloplasty, and could potentially decrease unnecessary surgeries as well as time to treatment.
    . Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: PURPOSE In this study we explore the utility and performance of a dedicated high resolution molecular breast imaging device, positron emission mammography (PEM), in noninvasively staging the axillae in patients with newly diagnosed breast cancer. METHOD AND MATERIALS 33 patients with biopsy-proven, newly diagnosed breast cancer were imaged on a Flex Solo II PEM Scanner (Naviscan, San Diego, CA) following intravenous foot injection of 10 mCi of FDG. Standard tomographic medial-lateral oblique and cranio-caudal views with additional dedicated axillary (AX) views were acquired for both breasts. Images were reviewed by 2 radiologists experienced in PEM. Axillary lymph node (LN) uptake was graded subjectively as absent, mild, or marked. In addition, semiquantitative PEM uptake values (PUV) and lesion to background (LTB) ratios were calculated. Results were compared with pathologic axillary LN findings after surgery. RESULTS For the 33 patients, 65 AX views were obtained. 22 axillae demonstrated mild LN uptake (in 16 patients) and 7 axillae demonstrated marked LN uptake (in 7 patients). After surgery, 12 axillae in 12 patients were found to have axillary LN metastases on pathology. Using mild or greater uptake as a cutoff, the sensitivity and specificity of PEM in detecting LN metastases was 75% and 74%, respectively. Using marked uptake as a cutoff, the sensitivity and specificity was 50% and 98%. PUV (range 0.3-1.5) was not found to correlate with the presence of LN metastases. However, using a LTB threshold of 2.7 (range 1.5-25.0), 8 of 9 patients' axillae were true negatives and 9 of 10 patients were true positives (TP) . Using a LTB threshold of 4.0, 6 of 6 patients' axillae were TP. At path, the smallest volume of LN tumor detected by mild uptake was 1-mm3 and by marked uptake was 4-mm3. In 38% of patients, the additional AX views were deemed necessary for optimal axillary evaluation. In 62%, standard views were sufficient. CONCLUSION Qualitative visual analysis of the axillae using PEM is highly specific but only moderately sensitive in detecting LN metastases in patients with breast cancer. Semiquantitative LTB ratios may also be very useful in identifying tumor. Micrometastases as small as 1-mm may be seen. CLINICAL RELEVANCE/APPLICATION Given its high specificity, patients with axillae abnormal on PEM could potentially skip sentinel LN procedures and have assumed LN metastases. Semiquantitative LTB analysis also appears promising.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: No study to test the feasibility and prognostic value of the number of primary tumors, the number of positive lymph nodes, and the total number of tumors in the whole body as tumor burden measurements on FDG PET/CT imaging has been reported. To determine whether the number of tumors seen in 18F-FDG PET scans can be a prognostic factor in non-surgical patients with non-small cell lung cancer (NSCLC). One hundred and forty patients with histologically proven NSCLC and baseline 18F-FDG PET scan before therapy were identified in this retrospective analysis. The total number of tumors (TTn) in the whole body, the number of primary tumors (Tn), positive lymph nodes (Nn), and distant metastases (Mn), along with the maximum standardized uptake values (SUV(max)) of the tumors were measured. Inter-observer variability of the total number of tumors, counted by two radiologists, was assessed. Survival analyses were performed to determine the prognostic value of the number of tumors. Concordance correlation coefficients for the TTn, Tn, Nn, and Mn were all greater than 0.85. TTn and Nn were strong prognostic factors of NSCLC patients' overall survival (OS). In univariate Cox regression models, gender, stage, TTn, Nn, and Mn were statistically significant factors (P = 0.016, 0.032, <0.001, <0.001, and 0.006, respectively). In multivariate Cox regression models, TTn and Nn remained as statistically significant predictors for survival with hazard ratios (HR) of 1.06 (P = 0.001) and 1.11 (P = 0.002), respectively, after adjusting for clinical stage based 7th edition of TNM staging system, age, gender, and SUV(max). Patients with a TTn ≤4 (cutpoint based on median value) had a median OS of 15.2 months compared with 9.0 months for those with TTn >4. Measuring the number of tumors on FDG PET imaging is easy to perform with minimal inter-observer variability. The total number of tumors and number of nodal metastases, as metabolic tumor burden measurements in 18F-FDG PET/CT, are prognostic markers independent of clinical stage, age, gender, and SUV measurement in non-surgical patients with NSCLC.
    Acta Radiologica 06/2012; 53(5):561-8. · 1.33 Impact Factor
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    ABSTRACT: PURPOSE: To determine whether whole-body metabolic tumor burden, measured as either metabolic tumor volume (MTV(WB)) or total lesion glycolysis (TLG(WB)), using FDG-PET/CT is an independent prognostic marker in non-small cell lung cancer (NSCLC). METHODS: 328 patients with histologically proven NSCLC were identified for this retrospective analysis. This study was approved by our Institutional Review Board. All patients underwent baseline (18)F-FDG-PET/CT scan imaging before therapy. The MTV(WB), TLG(WB), maximum standardized uptake value (SUV(maxWB)) and mean standardized uptake value (SUV(meanWB)) of tumors throughout the whole body were measured from FDG-PET images with semi-automated 3D contouring software. RESULTS: In univariate analysis, there was a statistically significant association of overall survival (OS) with the MTV(WB) (hazard ratio (HR) = 1.62, p < 0.001), TLG(WB) (HR = 1.47, p < 0.001). The patients with a MTV(WB) ≤ median of 65.7 ml and TLG(WB) ≤ median of 205.11 SUV(mean) * ml had a median OS of 41.1 and 35.4 months compared with 9.5 and 9.7 months for those with a MTV(WB) > 65.7 ml and TLG(WB) > 205.11 SUV(mean) * ml, respectively. From a series of multivariate Cox regression models, the MTV(WB) and TLG(WB) were significantly better than SUV(maxWB) and SUV(meanWB) at prognostication and significantly associated with patients' OS with HRs of 1.50 (p < 0.001) and 1.42 (p < 0.001), respectively, after adjustment for patient's age, gender and treatment intent as well as the tumor SUV(maxWB), histology and stage. CONCLUSIONS: MTV(WB) and TLG(WB) as metabolic tumor burden measurements in (18)F-FDG-PET/CT are independent prognostic markers and are significantly better than SUV(maxWB) and SUV(meanWB) at prognostication.
    International Journal of Computer Assisted Radiology and Surgery 05/2012; · 1.36 Impact Factor
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    ABSTRACT: Presented at European Congress of the European Association of Nuclear Medicine - Milan, Italy 2012
    Presented at European Congress of the European Association of Nuclear Medicine - Milan, Italy 2012; 03/2012
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    ABSTRACT: Stage IV non-small-cell lung cancer (NSCLC) consists of a heterogeneous group of patients with different prognoses. We assessed the prognostic value of baseline whole body tumor burden as measured by metabolic tumor volume (MTV), total lesion glycolysis (TLG), and standardized uptake values (SUV(max) and SUV(mean)) of all tumors in nonsurgical patients with Stage IV NSCLC. Ninety-two consecutive patients with newly diagnosed Stage IV NSCLC who had a pretreatment F-18 fludeoxyglucose positron emission tomography/computed tomography scan were retrospectively reviewed. The MTV, TLG, SUV(mean), and SUV(max) of whole-body (WB) tumors were measured with the MIMvista workstation with manual adjustment. There was a statistically significant association between overall survival (OS) and ln(MTV)/ln(TLG) at the level of WB tumor burden (MTV(WB)) and of primary tumor (MTV(T)). The hazard ratio (HR) for a 1-unit increase of ln(MTV(WB)) and ln(MTV(T)) before and after adjusting for age and gender was 1.48/1.48 (both P < .001) and 1.25/1.25 (P = .006, .007), respectively. The HR for a 1-unit increase of ln(TLG(WB)) and ln(TLG(T)) before and after adjusting for age and gender was 1.37/1.37 (both P = .001) and 1.19/1.19 (P = .001, .017), respectively. There was no statistically significant association between OS and ln(SUV(max)) and ln(SUV(mean)) at WB tumor burden, primary tumor, nodal metastasis, or distant metastasis (P > .05). There was low interobserver variability between two radiologists with concordance correlation coefficients of 0.90 for ln(MTV(WB)) and greater than 0.90 for SUV(maxWB), SUV(meanWB), and ln(TLG(WB)). Baseline WB metabolic tumor burden, as measured with MTV and TLG, is a prognostic measurement in patients within Stage IV NSCLC with low interobserver variability. This study also suggests pretreatment MTV and TLG measurements may be used to further stratify patients with Stage IV NSCLC and are better prognostic measures than SUV(max) and SUV(mean) measurements.
    Academic radiology 01/2012; 19(1):69-77. · 2.09 Impact Factor
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    ABSTRACT: PURPOSE To assess the prognostic value of baseline whole body tumor burden as measured by metabolic tumor volume (MTV), total lesion glycolysis (TLG) and standardized uptake value (SUVmax and SUVmean) of all tumors in patients non-small cell lung cancer (NSCLC ) who were treated surgically. METHOD AND MATERIALS 92 consecutive patients (47 males, 45 females) with newly diagnosed NSCLC who had FDG PET/CT scans before the surgery were retrospectively reviewed. The FGD PET/CT scans were performed in accordance with National Cancer Institute guidelines. The MTV, TLG as well as the SUVmean and SUVmax of whole-body tumors were measured with the PETedge tool on MIMvista workstation with manual adjustment. The median follow-up among 62 survivors is 50 months from initial diagnosis (range of 3 to 81 months). Statistical methods included log-rank tests and Cox regression. RESULTS Mean±SD levels at baseline for log MTV, log TLG, SUVmean, and SUVmax were: 2.9±1.6, 3.9±2.1, 3.4±1.9, and 7.9±5.9, respectively. There were a total of 30 deaths during follow-up. Median overall survival (OS) was not yet reached. There was a statistically significant association, after adjusting for cancer stage, between OS and log MTV (Hazard Ratio [HR] for 1 SD increase=1.41, 95% CI (1.09,1.81, p=0.008), and log TLG (HR for 1 SD increase=1.30, 95% CI (1.06, 1.60, p=0.012) measured on baseline PET/CT but not log SUVmax and log SUVmean (p=0.083 and 0.092, respectively). There was a statistically significant association, after adjusting for cancer stage, between progression-free survival and log MTV (Hazard Ratio [HR] for 1 SD increase=1.26, 95% CI (1.03,1.54, p = 0.028), log TLG (HR for 1 SD increase=1.18, 95% CI (1.01, 1.38, p = 0.042 ) measured on baseline PET/CT but not log SUVmax and log SUVmean (p=0.201, and 0.227). CONCLUSION Baseline whole-body metabolic tumor burden as measured with MTV or TLG on PET/CT is a prognostic measurement independent on the patient’s clinical TNM staging in NSCLC treated surgically. CLINICAL RELEVANCE/APPLICATION Whole-body metabolic tumor burden in surgical patients with NSCLC on the baseline PET/CT may help to further stage the patients for more appropriate therapy or clinical trial.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 11/2011
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    ABSTRACT: The objective of this study was to assess the prognostic value of metabolic tumor burden on 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) positron emission tomography (PET)/CT measured with metabolic tumor volume (MTV) and total lesion glycolysis (TLG), independent of Union Internationale Contra la Cancrum (UICC)/American Joint Committee on Cancer (AJCC) tumor, node, and metastasis (TNM) stage, in comparison with that of standardized uptake value (SUV) in nonsurgical patients with non-small cell lung cancer (NSCLC). This study retrospectively reviewed 169 consecutive nonsurgical patients (78 men, 91 women, median age of 68 years) with newly diagnosed NSCLC who had pretreatment (18)F-FDG PET/CT scans. The (18)F-FDG PET/CT scans were performed in accordance with National Cancer Institute guidelines. The MTV of whole-body tumor (MTV(WB)), of primary tumor (MTV(T)), of nodal metastases (MTV(N)), and of distant metastases (MTV(M)); the TLG of whole-body tumor (TLG(WB)), of primary tumor (TLG(T)), of nodal metastases (TLG(N)), and of distant metastases (TLG(M)); the SUV(max) of whole-body tumor (SUV(maxWB)), of primary tumor (SUV(maxT)), of nodal metastases (SUV(maxN)), and of distant metastases (SUV(maxM)) as well as the SUV(mean) of whole-body tumor (SUV(meanWB)), of primary tumor (SUV(meanT)), of nodal metastases (SUV(meanN)), and of distant metastases (SUV(meanM)) were measured with the PETedge tool on a MIMvista workstation with manual adjustment. The median follow-up among survivors was 35 months from the PET/CT (range 2-82 months). Statistical methods included Kaplan-Meier curves, Cox regression, and C-statistics. There were a total of 139 deaths during follow-up. Median overall survival (OS) was 10.9 months [95% confidence interval (CI) 9.0-13.2 months]. The MTV was statistically associated with OS. The hazard ratios (HR) for 1 unit increase of ln(MTV(WB)), √(MTV(T)), √(MTV(N)), and √(MTV(M)) before/after adjusting for stage were: 1.47/1.43 (p < 0.001/<0.001), 1.06/1.05 (p < 0.001/<0.001), 1.11/1.10 (p < 0.001/<0.001), and 1.04/1.03 (p = 0.007/0.043), respectively. TLG had statistically significant associations with OS with the HRs for 1 unit increase in ln(TLG(WB)), √(TLG(T)), √(TLG(N)), and √(TLG(M)) before/after adjusting for stage being 1.36/1.33 (p < 0.001/<0.001), 1.02/1.02 (p = 0.001/0.002), 1.05/1.04 (p < 0.001/<0.001), and 1.02/1.02 (p = 0.003/0.024), respectively. The ln(SUV(maxWB)) and √(SUV(maxN)) were statistically associated with OS with the corresponding HRs for a 1 unit increase before/after adjusting for stage being 1.46/1.43 (p = 0.013/0.024) and 1.22/1.16 (p = 0.002/0.040). The √(SUV(meanN)) was statistically associated with OS before and after adjusting for stage with HRs for a 1 unit increase of 1.32 (p < 0.001) and 1.24 (p = 0.015), respectively. The √(SUV(meanM)) and √(SUV(maxM)) were statistically associated with OS before adjusting for stage with HRs for a 1 unit increase of 1.26 (p = 0.017) and 1.18 (p = 0.007), respectively, but not after adjusting for stage (p = 0.127 and 0.056). There was no statistically significant association between OS and √(SUV(maxT)), ln(SUV(meanWB)), or √(SUV(meanT)). There was low interobserver variability among three radiologists with intraclass correlation coefficients (ICC) greater than 0.94 for SUV(maxWB), ln(MTV(WB)), and ln(TLG(WB)). Interobserver variability was higher for SUV(meanWB) with an ICC of 0.806. Baseline metabolic tumor burdens at the level of whole-body tumor, primary tumor, nodal metastasis, and distant metastasis as measured with MTV and TLG on FDG PET are prognostic measures independent of clinical stage with low inter-observer variability and may be used to further stratify nonsurgical patients with NSCLC. This study also suggests MTV and TLG are better prognostic measures than SUV(max) and SUV(mean). These results will need to be validated in larger cohorts in a prospective study.
    European Journal of Nuclear Medicine 09/2011; 39(1):27-38. · 4.53 Impact Factor
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    ABSTRACT: In order to aid radiologists' routine work for interpreting bone scan images, we developed a computerized method for temporal subtraction (TS) images which can highlight interval changes between successive whole-body bone scans, and we performed a prospective clinical study for evaluating the clinical utility of the TS images. We developed a TS image server which includes an automated image-retrieval system, an automated image-conversion system, an automated TS image-producing system, a computer interface for displaying and evaluating TS images with five subjective scales, and an automated data-archiving system. In this study, the radiologist could revise his/her report after reviewing the TS images if the findings on the TS image were confirmed retrospectively on our clinical picture archiving and communication system. We had 256 consenting patients of whom 143 had two or more whole-body bone scans available for TS images. In total, we obtained TS images successfully in 292 (96.1%) pairs and failed to produce TS images in 12 pairs. Among the 292 TS studies used for diagnosis, TS images were considered as "extremely beneficial" or "somewhat beneficial" in 247 (84.6%) pairs, as "no utility" in 44 pairs, and as "somewhat detrimental" in only one pair. There was no TS image for any pairs that was considered "extremely detrimental." In addition, the radiologists changed their initial reported impression in 18 pairs (6.2%). The benefit to the radiologist of using TS images in the routine interpretation of successive whole-body bone scans was significant, with negligible detrimental effects.
    Journal of Digital Imaging 08/2011; 24(4):680-7. · 1.10 Impact Factor
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    ECR (European Congress of Radiology), 10.1594/ecr2011/C-1260C-1260, March 3-7, 2011, Vienna, Austria; 03/2011
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    ABSTRACT: (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET) imaging has been shown to be an accurate method for diagnosing pulmonary lesions, and the standardized uptake value (SUV) has been shown to be useful in differentiating benign from malignant lesions. To survey the interobserver variability of SUV(max) and SUV(mean) measurements on (18)F-FDG PET/CT scans and compare them with tumor size measurements on diagnostic CT scans in the same group of patients with focal pulmonary lesions. Forty-three pulmonary nodules were measured on both (18)F-FDG PET/CT and diagnostic chest CT examinations. Four independent readers measured the SUV(max) and SUV(mean) of the (18)F-FDG PET images, and the unidimensional nodule size of the diagnostic CT scans (UD(CT)) in all nodules. The region of interest (ROI) for the SUV measurements was drawn manually around each tumor on all consecutive slices that contained the nodule. The interobserver reliability and variability, represented by the intraclass correlation coefficient (ICC) and coefficient of variation (COV), respectively, were compared among the three parameters. The correlation between the SUV(max) and SUV(mean) was also analyzed. There was 100% agreement in the SUV(max) measurements among the 4 readers in the 43 pulmonary tumors. The ICCs for the SUV(max), SUV(mean), and UD(CT) by the four readers were 1.00, 0.97, and 0.97, respectively. The root-mean-square values of the COVs for the SUV(max), SUV(mean), and UD(CT) by the four readers were 0%, 13.56%, and 11.03%, respectively. There was a high correlation observed between the SUV(max) and SUV(mean) (Pearson's r=0.958; P <0.01). This study has shown that the SUV(max) of lung nodules can be calculated without any interobserver variation. These findings indicate that SUV(max) is a more valuable parameter than the SUV(mean) or UD(CT) for the evaluation of therapeutic effects of chemotherapy or radiation therapy on serial studies.
    Acta Radiologica 09/2010; 51(7):782-8. · 1.33 Impact Factor
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    ABSTRACT: The authors report the fluorodeoxyglucose (FDG)-positron emission tomography(PET)/computed tomography (CT) findings of a rare case of growth hormone-secreting pituitary carcinoma with multiple metastatic lesions to the skeleton. A 31-year-old male had presented with acromegaly and had received transsphenoidal resection of a pituitary tumor and adjuvant radiotherapy. However, the tumor recurred with local invasions and the patient underwent more resections and adjuvant chemotherapy. Several months later, the patient developed rising levels of insulin-like growth factor 1 and whole-body FDG-PET/CT scanning revealed multiple hypermetabolic lesions throughout the skeleton compatible with metastasis.
    Cancer Imaging 01/2010; 10:114-6. · 1.59 Impact Factor
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    ABSTRACT: PURPOSE To compare the reproducibility of the maximal standardized uptake value (SUV) on FDG PET with that of the tumor size measurement on diagnostic CT. METHOD AND MATERIALS We retrospectively reviewed 36 PET/CT scans and 44 diagnostic CT scans in 29 consecutive patients with biopsy-proven lymphoma for initial staging and restaging after chemotherapy. Scans were performed with a PET/CT scanner one hour after the injection of 10 to 20 mCi FDG. All CT scans were obtained with spiral CT scanners. The PET, PET/CT fusion and non-diagnostic CT images were reviewed and maximal SUV (SUVmax) were measured independently by two nuclear medicine physicians with CT experience. The SUVmax of a discrete tumor or of a cluster of confluent tumors was measured on each FDG PET scan using a PET workstation. All slices that contained the tumor(s) were used in the measurement of the SUVmax so that the whole tumor(s) was included in the region of interest. The maximal length and width of the tumor(s) were measured on the axial slice on which the tumor(s) had the maximal cross-sectional dimension using our Stentor PACS system. ANOVA was used to estimate the inter-observer variability with SPSS 10.01. The mean square errors between two sets of the measurements by two physicians were used to determine the inter-observer variability of the PET and CT measurements. RESULTS The inter-observer mean square errors of SUVmax on PET/CT, the length of the tumor on CT and the tumor width on CT are 0.00, 215.16 mm 2, and 24.36 mm2, respectively. CONCLUSION Although many physiological and technical factors can affect SUVmax measurement, they are considered to have a negligible effect on assessing change of SUVmax on initial and follow-up scans. Our study shows that SUVmax measurement is not observer-dependent and without inter-observer variation. However, CT measurements of the tumor length and width are observer-dependent with an inter-observer variability. CLINICAL RELEVANCE/APPLICATION Knowing reproducibility difference between SUVmax on PET/CT and CT tumor size measurements is important in the evaluating therapeutic response of tumors, especially in clinical trials.
    Radiological Society of North America 2007 Scientific Assembly and Annual Meeting; 11/2007
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    ABSTRACT: PURPOSE/AIM To demonstrate advantages of an imaging workstation which includes a temporal subtraction technique for identification of interval changes on two successive whole-body bone scans, and a contralateral subtraction technique for enhancement of asymmetric subtle lesions on single whole-body bone scans. CONTENT ORGANIZATION This intelligent workstation is based on one that was developed for a prospective clinical study for evaluating the clinical utility of temporal subtraction (TS) images on successive whole-body bone scans. We will present several bone scan cases for which TS images were considered beneficial, and cases for which radiologists' initial findings were changed by use of TS images in the prospective clinical study. Contralateral subtraction (CS) images will also be displayed. SUMMARY The TS (CS) images were obtained by subtracting the nonlinearly-warped previous image (the mirror image of the current image) from the current image in order to highlight interval changes or asymmetric lesions. Preliminary results indicated that the TS images were beneficial in 83.0 % (44/53) cases, and radiologists changed their initial findings in 5.7 % (3/53) cases by use of the TS images. In one case (1.9%) the TS was somewhat detrimental, but in no case TS was for extremely detrimental.
    Radiological Society of North America 2007 Scientific Assembly and Annual Meeting; 11/2007
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    ABSTRACT: Although the prevalence of pineal cysts in autopsy series has been reported as being between 25% and 40%, MR studies have documented their frequency to range between 1.5% and 10.8%. The purpose of this high-resolution brain MR imaging study at 1.9T was to determine the prevalence of pineal cysts in healthy adults. Brain MR images of 100 healthy young volunteers were randomly selected from our International Consortium for Brain Mapping project data base. Cysts were detected as circular areas of isointensity relative to CSF on both 3D gradient-echo T1-weighted and 2D fast spin-echo T2-weighted images. The inner diameters of all visualized pineal cysts were measured, and a criterion of 2.0 mm of the largest inner cross-sectional diameter was used to categorize cysts as being either small cystic changes (<2.0-mm diameter) or pineal cysts (>2.0-mm diameter). Twenty-three percent (23/100) of the volunteers had pineal cysts with a mean largest inner cross-sectional diameter of 4.3 mm (range, 2-14 mm); 13% (13/100) demonstrated cystic changes involving the pineal gland with the largest inner cross-sectional diameter of less than 2.0 mm. There was a slight female predominance. Two subjects with long-term follow-up scans showed no symptoms or changes in the size of their pineal cysts. On high-resolution MR imaging, the prevalence of pineal cysts was 23% in our healthy group of adults, which is consistent with previous autopsy studies. Long-term follow-up studies of 2 cases demonstrated the stability of the cysts.
    American Journal of Neuroradiology 11/2007; 28(9):1706-9. · 3.17 Impact Factor
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    ABSTRACT: We evaluated the usefulness of temporal subtraction images obtained from two successive whole-body bone scans, in terms of improvement in radiologists' diagnostic accuracy in detecting interval changes and of a reduction in reading time, by use of a jackknife free-response receiver operating characteristic (JAFROC) analysis method. Twenty pairs of successive whole-body bone scans (72 consented interval changes) and their temporal subtraction images were used for an observer performance study. Our institutional review board approved the use of this database and the participation of radiologists in this study. In the first session of the observer study, without temporal subtraction images, the previous and current images were shown to five radiologists independently for their marking of the locations on current images and confidence ratings on potential interval changes from previous images. In the second session, temporal subtraction images were shown together with the modified previous and current images. JAFROC analysis was used for assessing the statistical significance of differences between radiologists' performance without and with temporal subtraction images. The average sensitivity for detecting interval changes was improved from 58.6% to 73.2% at a false-positive rate of two per case by use of temporal subtraction images, and the difference was statistically significant by use of JAFROC analysis (P = .035). In addition, the mean reading time per case was reduced considerably from 134 seconds to 91 seconds (P < .01). Temporal subtraction imaging for successive whole-body bone scans has the potential greatly to assist radiologists by increasing both their accuracy and productivity.
    Academic Radiology 08/2007; 14(8):959-66. · 1.91 Impact Factor
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    ABSTRACT: We developed a computer-aided diagnostic (CAD) scheme for assisting radiologists in the detection of asymmetric abnormalities on a single whole-body bone scintigram by applying a contralateral subtraction (CS) technique. Twenty whole-body bone scans including 107 abnormal lesions in anterior and/or posterior images (the number of lesions per case ranged from 1 to 16, mean 5.4) were used in this study. In our scheme, the original bone scan image was flipped horizontally to provide a mirror image. The mirror image was first rotated and shifted globally to match the original image approximately, and then was nonlinearly warped by use of an elastic matching technique in order to match the original image accurately. We applied a nonlinear lookup table to convert the difference in pixel values between the original and the warped images to new pixel values for a CS image, in order to enhance dark shadows at the locations of abnormal lesions where uptake of radioisotope was asymmetrically high, and to suppress light shadows of the lesions on the contralateral side. In addition, we applied a CAD scheme for the detection of asymmetric abnormalities by use of rule-based tests and sequential application of artificial neural networks with 25 image features extracted from the original and CS images. The performance of the CAD scheme, which was evaluated by a leave-one-case-out method, indicated an average sensitivity of 80.4 % with 3.8 false positives per case. This CAD scheme with the contralateral subtraction technique has the potential to improve radiologists' diagnostic accuracy and could be used for computerized identification of asymmetric abnormalities on whole-body bone scans.
    Proc SPIE 03/2007;
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    ABSTRACT: Bone scintigraphy is the most frequent examination among various diagnostic nuclear medicine procedures. It is a well-established imaging modality for the diagnosis of osseous metastasis and for monitoring osseous tumor response to chemotherapy and radiation therapy. Although the sensitivity of bone scan examinations for detection of bone abnormalities has been considered to be relatively high, it is time consuming to identify multiple lesions such as bone metastases of prostate and breast cancers. In addition, it is very difficult to detect subtle interval changes between two successive abnormal bone scans, because of variations in patient conditions, the accumulation of radioisotopes during each examination, and the image quality of gamma cameras. Therefore, we developed a new computer-aided diagnostic (CAD) scheme for the detection of interval changes in successive whole-body bone scans by use of a temporal subtraction image which was obtained with a nonlinear image-warping technique. We carried out 58 pairs of successive bone scans in which each scan included both posterior and anterior views. We determined 107 "gold-standard" interval changes among the 58 pairs based on the consensus of three radiologists. Our computerized scheme consisted of seven steps, i.e., initial image density normalization on each image, image matching for the paired images, temporal subtraction by use of the nonlinear image-warping technique, initial detection of interval changes by use of temporal-subtraction images, image feature extraction of candidates of interval changes, rule-based tests by use of 16 image features for removing some false positives, and display of the computer output for identified interval changes. One hundred seven gold standard interval changes included 71 hot lesions (uptake was increased compared with the previous scan, or there was new uptake in the current scan) and 36 cold lesions (uptake was decreased or disappeared) for anterior and posterior views. The overall sensitivity in the detection of interval changes, including both hot and cold lesions evaluated by use of the resubstitution and the leave-one-case-out methods, were 95.3%, with 5.97 false positives per view, and 83.2% with 6.02, respectively. The temporal subtraction image for successive whole-body bone scans has the potential to enhance the interval changes between two images, which also can be quantified. Furthermore, the CAD scheme for the detection of interval changes by use of temporal subtraction images would be useful in assisting radiologists' interpretation on successive bone scan images.
    Medical Physics 02/2007; 34(1):25-36. · 2.91 Impact Factor

Publication Stats

912 Citations
179.00 Total Impact Points

Institutions

  • 2006–2013
    • University of Chicago
      • Department of Radiology
      Chicago, Illinois, United States
  • 2011
    • Kumamoto University
      • Department of Medical Physics
      Kumamoto, Kumamoto Prefecture, Japan
  • 2010
    • The University of Chicago Medical Center
      • Department of Radiology
      Chicago, IL, United States
    • Chang Gung Memorial Hospital
      • Department of Nuclear Medicine
      Taipei, Taipei, Taiwan
  • 1999–2007
    • University of Texas Health Science Center at San Antonio
      • • Research Imaging Institute
      • • Division of Hospital Medicine
      San Antonio, Texas, United States
    • Texas Tech University Health Sciences Center
      • Department of Physiology
      Lubbock, TX, United States
  • 2000
    • University of Texas Health Science Center at Tyler
      Tyler, Texas, United States
    • The University of Hong Kong
      Hong Kong, Hong Kong