Sung Yoon Park

Mesenchymal progenitor cells in the human umbilical cord.

Mesenchymal progenitor or stem cells (MPCs) isolated from fetal blood, liver, and bone marrow are a population of multipotential cells that can proliferate and differentiate into multiple mesodermal tissues including bone, cartilage, muscle, ligament, tendon, fat, and stroma. The objective of this study was to isolate and characterize MPCs in the human umbilical cord. The suspensions of endothelial and subendothelial cells in cord vein were collected and cultured in M199 supplemented with 10% fetal bovine serum (FBS). Of 50 umbilical cord samples, 3 had numerous fibroblastoid cells morphologically distinguishable from endothelial cells. Fibroblastic cells displayed lack of expression of vWF, Flk-1, and PECAM-1, indicating the endothelial cell-specific marker. To investigate the differentiation potentials, the cells were cultured in adipogenic or osteogenic medium for 2 weeks. Fibroblast-like cells treated with adipogenic supplementation showed Oil red O-positive staining and expressed adipsin, FABP4, LPL, and PPARγ2 genes by reverse transcriptase polymerase chain reaction (RT-PCR). In osteogenic differentiation, alkaline phosphatase activity and calcium accumulation were detected. RT-PCR studies determined that Cx43, osteopontin, and Runx2 genes were expressed in the osteogenic cultures. Among three cell lines cultured continuously for passage 10, two had normal karyotypes; however, one retained a karyotype of mos 46,XY[19]/47,XY,+mar[3]. These observations suggest that MPCs are present in human umbilical cord and possess several typical traits of MPCs.

Prediction of biochemical recurrence following radical prostatectomy in men with prostate cancer by diffusion-weighted magnetic resonance imaging: initial results

ObjectiveTo retrospectively assess the apparent diffusion coefficient (ADC) as a predictor of biochemical recurrence (BCR) after surgery in patients with localised prostate cancer.MethodsEnrolled in this study were 158 men who underwent surgery between 2005 and 2007 with preoperative diffusion-weighted MR imaging (DWI) at 3xa0T, and who received follow-up for a median of 24xa0months (range, 12–57xa0months). Univariate and multivariate analyses including all clinical variables and tumour ADC data were performed with respect to BCR. Receiver operating characteristic (ROC) analysis was also performed to assess diagnostic performance of variables in the prediction of BCR.ResultsThirty patients (19%) who received surgery had BCR. Univariate analysis revealed that tumour ADC, Gleason score at biopsy and surgical specimen, serum PSA, greatest percentage of cancer in biopsy core, percentage of positive cores in all biopsy cores and tumour volume were all significantly related to BCR. However, multivariate analysis identified tumour ADC as the only independently predictive factor. For predicting BCR, area under the curve for tumour ADC was 0.755, and tumour ADC showed better diagnostic performance than that of all other variables.ConclusionTumour ADC on DWI may be a predictive biomarker for BCR following radical prostatectomy.

Prostate Cancer: PI-RADS Version 2 Helps Preoperatively Predict Clinically Significant Cancers

Purpose To retrospectively analyze whether Prostate Imaging Reporting and Data System (PI-RADS) version 2 is helpful for the detection of clinically significant prostate cancer. Materials and Methods Institutional review board approved this retrospective study. A total of 425 patients with prostate cancer who had undergone magnetic resonance (MR) imaging and radical prostatectomy were included. Preoperative parameters such as prostate-specific antigen, biopsy Gleason score, greatest percentage of the core, percentage of the positive core number, and score at PI-RADS version 2 with MR imaging were investigated. Two independent readers performed PI-RADS scoring. Clinically significant prostate cancer was defined as follows: (a) Gleason score of 7 or greater, (b) tumor volume of 0.5 cm(3) or greater, or a (c) positive extracapsular extension or seminal vesicle invasion. The reference standard was based on review of surgical specimen. Logistic regression was conducted to determine which parameters are associated with the presence of clinically significant cancer. Interreader agreement (ie, score ≥4 or not) was investigated by using κ statistics. Results At univariate analysis, all of the preoperative parameters were significant for clinically significant prostate cancer (P < .05). However, multivariate analysis revealed that PI-RADS score was the only significant parameter for both readers (reader 1: odds ratio = 28.170, P = .002; reader 2: odds ratio = 5.474, P = .007). The interreader agreement was excellent for PI-RADS score of 4 or greater (weighted κ = 0.801; 95% confidence interval: 0.737, 0.865). Conclusion The use of PI-RADS version 2 may help preoperatively diagnose clinically significant prostate cancer. (©) RSNA, 2016.

Assessment of early response to concurrent chemoradiotherapy in cervical cancer: value of diffusion-weighted and dynamic contrast-enhanced MR imaging

PURPOSEnTo investigate diffusion-weighted (DWI) and dynamic contrast-enhanced MR imaging (DCE-MRI) as early response predictors in cervical cancer patients who received concurrent chemoradiotherapy (CCRT).nnnMATERIALS AND METHODSnSixteen patients with cervical cancer underwent DWI and DCE-MRI before CCRT (preTx), at 1week (postT1) and 4weeks (postT2) after initiating treatment, and 1month after the end of treatment (postT3). At each point, apparent diffusion coefficient (ADC) and DCE-MRI parameters were measured in tumors and gluteus muscles (GM). Tumor response was correlated with imaging parameters or changes in imaging parameters at each point.nnnRESULTSnAt each point, ADC, K(trans) and Ve in tumors showed significant changes (P<0.05), as compared with those of GM (P>0.05). PostT1 tumor ADCs showed a significant correlation with tumor size response at postT2 (P=0.041), and changes in tumor ADCs at postT1 had a significant correlation with tumor size (P=0.04) and volume response (P=0.003) at postT2. In tumors, preTx K(trans) and Ve showed significant correlations with tumor size at postT3 (P=0.011) and tumor size response at postT2 (P=0.019), respectively.nnnCONCLUSIONnDWI and DCE-MRI, as early biomarkers, have the potential to evaluate therapeutic responses to CCRT in cervical cancers.

Adenoma characterization: adrenal protocol with dual-energy CT.

PURPOSEnTo determine the diagnostic performance of dual-energy computed tomography (CT) by using virtual unenhanced CT to characterize adrenal masses.nnnMATERIALS AND METHODSnThis study is retrospective, HIPAA-compliant, and approved by the institutional review board. Between December 2009 and June 2010, 49 patients with 49 adrenal masses underwent 120-kVp unenhanced CT and 80-kVp and 140-kVp early and delayed contrast agent-enhanced dual-energy CT. Early virtual unenhanced (EVU) and delayed virtual unenhanced (DVU) CT images were composed of data sets of early and delayed contrast-enhanced CT, respectively. Adenomas were divided into lipid-rich adenoma and lipid-poor adenoma on the basis of lesion attenuation values measured according to unenhanced CT and percentage loss of enhancement. Absolute percentage loss of enhancement was calculated with the following equation: (CT(EE) - CT(DE)) × 100/(CT(EE) - CT(UE)), where CT(UE), CT(EE), and CT(DE) are adrenal mass attenuation values at unenhanced CT, early contrast-enhanced CT, and delayed contrast-enhanced CT, respectively. The sensitivity of adrenal protocol adenoma with delayed contrast-enhanced CT was obtained with a reference standard of unenhanced CT, pathologic examination, or size stability on follow-up examination findings. Lesion attenuation values measured on unenhanced CT, EVU CT, and DVU CT images were compared by using repeated measures analysis of variance with post hoc test.nnnRESULTSnOf 49 masses, 33 were adenomas and 16 were nonadenomas. Adenoma group was 18 lipid-rich adenomas and 15 lipid-poor adenomas. Mean attenuation values of the lipid-rich adenomas on EVU CT images (11.7 HU ± 9.5) were significantly greater than those on unenhanced CT images (0.7 HU ± 7.2) (P = .001) and DVU CT images (6.6 HU ± 8.4) (P = .01). The sensitivities of EVU CT and DVU CT for lipid-rich adenoma were 39% (seven of 18) and 61% (11 of 18), respectively. The sensitivity for adenoma with percentage loss of enhancement values calculated from virtual unenhanced CT and early and delayed contrast-enhanced CT was 100% (33 of 33).nnnCONCLUSIONnAlthough adrenal protocol with dual-energy CT by using virtual unenhanced CT and washout rate can help diagnose all lipid-poor adenomas, it may miss lipid-rich adenomas that can be diagnosed on unenhanced CT images.

Prostate cancer: role of pretreatment multiparametric 3-T MRI in predicting biochemical recurrence after radical prostatectomy.

OBJECTIVEnThe purpose of this study is to retrospectively investigate whether pretreatment multiparametric MRI findings can predict biochemical recurrence in patients who underwent radical prostatectomy (RP) for localized prostate cancer.nnnMATERIALS AND METHODSnIn this study, 282 patients with biopsy-proven prostate cancer who received RP underwent pretreatment MRI using a phased-array coil at 3 T, including T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced MRI (DCE-MRI). MRI variables included apparent tumor presence on combined imaging sequences, extracapsular extension, and tumor size on DWI or DCE-MRI. Clinical variables included baseline prostate-specific antigen (PSA) level, clinical stage, and Gleason score at biopsy. The relationship between clinical and imaging variables and biochemical recurrence was evaluated using Cox regression analysis.nnnRESULTSnAfter a median follow-up of 26 months, biochemical recurrence developed in 61 patients (22%). Univariate analysis revealed that all the imaging and clinical variables were significantly associated with biochemical recurrence (p < 0.01). On multivariate analysis, however, baseline PSA level (p = 0.002), Gleason score at biopsy (p = 0.024), and apparent tumor presence on combined T2WI, DWI, and DCE-MRI (p = 0.047) were the only significant independent predictors of biochemical recurrence. Of the independent predictors, apparent tumor presence on combined T2WI, DWI, and DCE-MRI showed the highest hazard ratio (2.38) compared with baseline PSA level (hazard ratio, 1.05) and Gleason score at biopsy (hazard ratio, 1.34).nnnCONCLUSIONnThe apparent tumor presence on combined T2WI, DWI, and DCE-MRI of pretreatment MRI is an independent predictor of biochemical recurrence after RP. This finding may be used to construct a predictive model for biochemical recurrence after surgery.

Characterization of Lipid-Poor Adrenal Adenoma: Chemical-Shift MRI and Washout CT

OBJECTIVEnThe purpose of this article is to retrospectively compare the accuracy of MRI and CT in characterizing lipid-poor adrenal adenomas with respect to lesion-attenuation values measured on unenhanced CT.nnnMATERIALS AND METHODSnFifty-two lipid-poor adrenal masses measuring greater than 10 HU on unenhanced CT were identified in 52 patients who underwent both chemical-shift MRI and washout CT. Accuracies using the adrenal-to-spleen ratio (< 0.71) or signal intensity index (> 16.5%) for MRI and using absolute (≥ 60%) or relative (≥ 40%) percentage washout for CT were calculated to determine which modality was more accurate for lipid-poor adenoma characterization. Sensitivities of MRI and CT were also compared according to the lesion-attenuation values measured on unenhanced CT. Follow-up imaging or histologic diagnosis was used as the standard reference. The McNemar test was used to compare the accuracies of CT and MRI.nnnRESULTSnLipid-poor adrenal masses consisted of 37 adenomas and 15 nonadenomas. The sensitivities and specificities for adenoma on MRI versus CT were 75.7% (28/37) versus 100% (37/37) and 60.0% (9/15) versus 80.0% (12/15), respectively. CT achieved a higher accuracy than did MRI (p = 0.008). The sensitivities for adenomas measuring 20 HU or less on unenhanced CT were 100% (12/12) in both MRI and CT, whereas those measuring more than 20 HU were 64.0% (16/25) and 100% (25/25) in MRI and CT, respectively.nnnCONCLUSIONnMRI is equivalent to CT for characterizing adenomas measuring 20 HU or less on unenhanced CT. However, MRI is inferior to CT for adenomas measuring more than 20 HU because of decreased MR sensitivity.

Dynamic contrast-enhanced 3-T MR imaging in cervical cancer before and after concurrent chemoradiotherapy

ObjectiveTo investigate the changes of dynamic contrast-enhanced MR imaging (DCE-MRI) parameters at 3xa0T in cervical cancer patients before and after concurrent chemoradiotherapy (CCRT), and to correlate the parameters with final tumour response to therapy.MethodsThirty-five patients with cervical cancer underwent DCE-MRI before CCRT, 4xa0weeks after starting therapy and at 1xa0month after the end of therapy. DCE-MRI parameters were calculated in the tumour and normal gluteus muscle. Final response to treatment as determined by changes in tumour size and volume was correlated with pre-treatment DCE-MRI parameters.ResultsDCE-MRI parameters (i.e. Ktrans, ve and kep) in the tumours showed significant changes in response to CCRT (Pu2009<u20090.05) and in particular Ktrans and ve demonstrated early significant increase (Pu2009<u20090.01), but those in normal muscle did not show a significant difference (Pu2009>u20090.05). Before therapy, the mean values of Ktrans, kep, ve and vp in the tumours were significantly greater than those in muscle (Pu2009<u20090.05). DCE-MRI parameters of the tumours at pre-treatment were not statistically associated with final tumour size or volume change.ConclusionDCE-MRI parameters may help evaluate early changes of cervical cancer to CCRT, but larger, more definitive studies are needed.Key Points• DCE-MRI offers new insights into tumour behaviour.• Changes in tumour size lag behind biomarkers which improve quickly in responders.• DCE-MRI is a non-invasive imaging technique that can characterize tumour vasculature.• DCE-MRI of cervical cancer may be useful in monitoring changes with therapy.

Ultrasound-guided Core Biopsy of Small Renal Masses: Diagnostic Rate and Limitations

PURPOSEnTo evaluate the feasibility and complications of ultrasound (US)-guided biopsy of small renal masses (SRMs) and to determine factors that contribute to nondiagnostic biopsy specimens.nnnMATERIALS AND METHODSnBetween June 2004 and May 2011, 58 consecutive patients underwent US-guided core biopsy of a SRM (>1 cm and ≤4 cm) using an 18-gauge core biopsy device. The diagnostic rate, histologic diagnosis, and complications of US-guided core biopsy were assessed. Mann-Whitney U and Fisher exact tests were used to compare diagnostic and nondiagnostic biopsy specimens. Univariate analysis was performed to determine the predictive factors for nondiagnostic biopsy specimens.nnnRESULTSnThere were 59 biopsies of SRMs performed, and the diagnostic rate was 81% (48 of 59). The mass size of diagnostic and nondiagnostic biopsy specimens ranged from 1.2-3.9 cm (2.4 cm±0.7) for diagnostic specimens and from 1.1-3.5 cm (1.9 cm±0.7) for nondiagnostic specimens (P = .024). Of the diagnostic biopsy specimens, 77% (37 of 48) were malignant, and 23% (11 of 48) were benign. Minor complications developed in 20.3% (12 of 59) of biopsies. The lesion size or core number threshold for decreasing diagnostic rate was 2 cm or three cores. A cystic mass, fewer cores (three or fewer cores), an upper pole mass, and a small mass (≤2 cm) significantly predicted a nondiagnostic biopsy specimen (P = .007-.046).nnnCONCLUSIONSnUS-guided core biopsy is a feasible and safe procedure for histologic diagnosis of a SRM. However, nondiagnostic rates may increase when a cystic mass is biopsied, a mass is located in an upper pole mass, a mass is 2 cm or less, and three cores or fewer are sampled.

Parametrial Invasion in Cervical Cancer: Fused T2-weighted Imaging and High-b-Value Diffusion-weighted Imaging with Background Body Signal Suppression at 3 T

PURPOSEnTo retrospectively investigate the value of fused T2-weighted and high-b-value diffusion-weighted imaging with background body signal suppression (DWIBS) at 3 T to evaluate parametrial invasion in cervical cancer.nnnMATERIALS AND METHODSnIn this institutional review board-approved study, 152 consecutive patients with biopsy-proven cervical cancer who underwent radical hysterectomies also underwent pretreatment magnetic resonance imaging (T2-weighted imaging and DWIBS) at 3 T. Two radiologists independently evaluated the presence of parametrial invasion at T2-weighted imaging, fused T2-weighted imaging and high-b-value DWIBS (ie, fused T2-weighted DWIBS), and combined T2-weighted imaging and fused T2-weighted DWIBS, and the results were compared with histopathologic findings.nnnRESULTSnParametrial invasion was identified by pathologic analysis in 37 of 152 patients (24.3%). For association with parametrial invasion, the specificity and accuracy of fused T2-weighted DWIBS (97.4% and 90.1%, respectively, for reader 1; 95.7% and 89.5%, respectively, for reader 2) and combined T2-weighted imaging and fused T2-weighted DWIBS (99.1% and 93.4%, respectively, for reader 1; 96.5% and 92.8%, respectively, for reader 2) were significantly better than those of T2-weighted imaging alone (88.7% and 85.5%, respectively, for reader 1; 85.2% and 83.6%, respectively, for reader 2) (all P < .05). The respective sensitivity of T2-weighted imaging, fused T2-weighted DWIBS, and combined T2-weighted imaging and fused T2-weighted DWIBS was 75.7%, 67.6%, and 75.7% for reader 1 and 78.4%, 70.3%, and 81.1% for reader 2, and did not show significant differences (P value, ≤.375 to >.999). The respective area under the curve for association with parametrial invasion of T2-weighted imaging, fused T2-weighted DWIBS, and combined T2-weighted imaging and fused T2-weighted DWIBS was 0.912, 0.951, and 0.976 for reader 1 and 0.890, 0.932, and 0.968 for reader 2 (P < .05). Interreader agreements were excellent (κ = 0.89, 0.9, and 0.86 for T2-weighted imaging, fused T2-weighted DWIBS, and combined T2-weighted imaging and fused T2-weighted DWIBS, respectively).nnnCONCLUSIONnFusion of high-b-value DWIBS with T2-weighted imaging can improve the diagnostic performance in association with parametrial invasion in cervical cancer compared with T2-weighted imaging alone.