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Background: This study proposed to quantitatively assess the value of spectral CT imaging parameters in differentiating different pathological types of lung cancer. Methods: Eighty five patients with lung cancer (66 non-mucinous adenocarcinomas, 7 Squamous cell carcinomas, 8 small cell carcinomas, 1 mucinous adenocarcinoma, 1 sarcomatoid carcinoma, 1 carcinoid, 1 large cell carcinoma) underwent CT plain scan, contrast enhanced CT scans in arterial phase (a) and venous phase (v) with spectral imaging mode on a GE Revolution Xtream CT scanner. The Spectral CT Imaging parameters: Iodine concentrations (IC) of lesion in arterial phase (ICLa) and venous phase (ICLv), Normalized IC (NICa/NICv)-normalized to the IC in the aorta, slope of the spectral HU curve (λHUa/λHUv) and monochromatic CT number (CT40keVa/CT40keVv, CT70keVa/CT70keVv) enhancement on 40 keV and 70 keV images were calculated. The One-way ANOVA or Kruskal-Wallis test was used to compare quantitative parameters among lung squamous carcinoma, small cell carcinoma and lung adenocarcinoma groups, Bonferroni method was used to correct P value for multiple comparisons. Results: Among the different pathological types of lung cancers, these quantitative parameters of spectral CT imaging CT70keVa has significant difference. The CT70keVa of lung adenocarcinoma was lower than small cell carcinoma (P = 0.048) and squamous cell carcinoma (P = 0.039), respectively. And these CT40keVa, CT70keVa/CT70keVv parameters of lung adenocarcinoma was lower than non-adenocarcinomas (P < 0.05). However, there was no significant difference in spectral CT parameters between small cell lung cancer and squamous cell lung cancer, small cell lung cancer and non-small cell carcinoma (P > 0.05). Conclusion: Spectral CT parameters may be of value in distinguishing different pathological types of lung cancer.

Background To explore the value of the quantitative parameters of low-dose computed tomography (CT) perfusion in the diagnosis of lung cancers of different pathological types. Methods Eighty-five patients with lung cancer confirmed by pathology underwent enhanced spectral CT imaging with a General Electric (GE) Revolution Xtream CT scanner, including 7 patients with lung squamous cell carcinoma, 8 patients with small cell carcinoma, 67 patients with lung adenocarcinoma, and 3 patients with other pathologies. The low-dose CT perfusion parameters [blood flow (BF), blood volume (BV), time of arrival (IRF TO), maximum slope of increase (MSI), mean transit time (MTT), positive enhancement integral (PEI), time to peak (TTP) and time to maximum (Tmax)] were calculated and compared among the first three groups. One-way analysis of variance (ANOVA) or the Kruskal-Wallis test was used to compare the quantitative parameters among the three groups, and the Bonferroni method was used to correct for multiple comparisons. Results Among the quantitative parameters, MSI was significantly different among the three lung cancers (adenocarcinoma vs. squamous cell carcinoma vs. small cell carcinoma: 11.37±8.74 vs. 2.35±0.88 vs. 1.40±0.26, respectively; P=0.016). The MSI of lung adenocarcinoma was lower than that of non-adenocarcinoma (P=0.001), and the MSI of small cell carcinoma was lower than that of non-small cell carcinoma (P=0.014). There were no significant differences in the other parameters among these three groups (P>0.05). Conclusions Low-dose CT perfusion parameters may have a certain value in classifying the pathological type of lung cancer.

Objective To explore the correlation between the spectral computed tomography (CT) imaging parameters and the Ki-67 labeling index in lung adenocarcinoma. Methods Spectral CT imaging parameters [iodine concentrations of lesions (ICLs) in the arterial phase (ICLa) and venous phase (ICLv), normalized IC in the aorta (NICa/NICv), slope of the spectral HU curve (λHUa/λHUv) and monochromatic CT number enhancement on 40 keV and 70 keV images (CT40keVa/v, CT70keVa/v)] in 34 lung adenocarcinomas were analyzed, and common molecular markers, including the Ki-67 labeling index, were detected with immunohistochemistry. Different Ki-67 labeling indexes were measured and grouped into four grades according to the number of positive-stained cells (grade 0, ≤1%; 1%30%). One-way analysis of variance (ANOVA) was used to compare the four different grades, and the Bonferroni method was used to correct the P value for multiple comparisons. A Spearman correlation analysis was performed to further research a quantitative correlation between the Ki-67 labeling index and spectral CT imaging parameters. Results CT40keVa, CT40keVv, CT70keVa and CT70keVv increased as the grade increased, and CT70keVa and CT70keVv were statistically significant (P

BACKGROUND This study quantitatively assessed the efficacy of spectral computed tomography (CT) imaging parameters for differentiating the malignancy and benignity of solitary pulmonary nodules (SPNs) manifesting as ground glass nodules (GGNs) and solid nodules (SNs). METHODS The study included 114 patients with SPNs (61 GGNs, and 53 SNs) who underwent CT plain and enhanced scans in the arterial (a) and venous (v) phases using the spectral imaging mode. The spectral CT imaging parameters included: iodine concentrations (IC) of lesions in the arterial (ICLa) and venous (ICLv) phases; normalized IC (NICa/NICv, normalized to the IC in the aorta); the slope of the spectral Hounsfield unit (HU) curve (λHUa/λHUv); and monochromatic CT number (CT40keVa/v, CT70keVa/v) enhancement on 40 and 70 keV images. The two-sample Mann-Whitney U test was used to compare quantitative parameters between malignant and benign SPNs, SNs, and GGNs. RESULTS Pathology revealed 75 lung cancer cases, 3 metastatic nodules, 14 benign nodules, and 22 inflammatory nodules. Among the 53 SNs there were 37 malignant and 16 benign nodules. Among the 61 GGNs there were 41 malignant and 20 benign nodules. Overall, the CT40keVa, λHUa, CT40keVv, λHUv, and ICLv of benign SPNs were all greater than those of malignant SPNs (all P < 0.05). For GGNs, CT40keVa/v, CT70keVa/v, λHUa/λHUv, and ICLv of malignant GGNs were all lower than those of benign GGNs. CONCLUSION Spectral CT imaging is a more promising method for distinguishing malignant from benign nodules, especially in nodules manifesting as GGNs in contrast-enhanced scanning.

Background: The aim of this study was to investigate differences in the imaging features of mass-like tuberculosis and lung cancer on conventional MR sequences to improve the diagnostic ability for pulmonary masses. Methods: Thirty patients with suspicious pulmonary lesions were enrolled and diagnosed with tuberculosis by pathology or comprehensive clinical diagnoses. Twenty-six cases of lung cancer were retrospectively analyzed. Transverse fat-suppressed T2-weighted (T2W) imaging and T1-weighted (T1W) imaging were obtained at 1.5 Tesla. The imaging characteristics of lesions on the T2W and T1W images were compared between the two groups. The imaging features of enlarged mediastinal lymph nodes on T2W images were studied and compared. Results: On T2W images, there was a higher percentage of lesions containing hypointensity in the tuberculosis group (GTB) than in the lung cancer group (GLC) (P=0.004).The incidence of lesions demonstrating heterogeneous intensity was significantly greater in the GTB than in the GLC (70.0% vs . 7.7%, P=0.001). Approximately 92.3% of the lung cancer cases showed hyperintensity, a proportion substantially greater than that in the GTB (6.7%). On T1W images, more cases showed hyperintensity in the GTB than in the GLC (43.3% vs . 7.7%, P=0.003). The signal intensity ratios (SIRs) of the lesion to rhomboid muscle on T2W and T1W images were significantly different between the two groups. The mean intrasubject standard deviation (SD) of lesions in the GTB was markedly greater than that in the GLC on both T2W and T1W images. Benign mediastinal lymph nodes in the GTB showed a variety of signals on T2W images, whereas 80% of metastatic mediastinal lymph nodes displayed slight homogeneous hyperintensity, and this difference between the two groups was statistically significant. Conclusions: Conventional MR sequences can reveal the essential differences between mass-like tuberculosis and lung cancer and may be helpful for discriminating pulmonary masses.

Background: Much attention has been given to venous thromboembolism (VTE) disease, and many guidelines for prophylaxis have been published. However, there are few published data on patients who underwent thoracotomy. This study is to compare the effect of low molecular weight heparin (LMWH) combined mechanical approaches with mechanical approaches alone in prevention of VTE in the post thoracotomy cancer patients. Methods: This study used a prospective, randomized-controlled design. Patients with cancer who were scheduled for thoracotomy were divided into two groups: group A and group B. In group A, patients were given intermittent pneumatic compression (IPC) and elastic stockings (ES) postoperatively. Additionally, at 24 hours post-operation, patients were subcutaneously injected with LMWH calcium (nadroparin calcium; GlaxoSmithKline, China) for 7 days. In group B, patients were only given postoperative IPC and ES. The primary end points were incidence of pulmonary embolism (PE), deep vein thrombosis (DVT), and the PE severity index (PESI) of PE patients. The secondary end points were hemoglobin (HGB), platelet (PLT), D-dimer, the PO2/FiO2 ratio (P/F) at postoperative day (POD) 7, the chest drainage time (CDT) and the length of stay (LOS) in hospital after operation. Results: A total of 90 patients were included in the final data analysis (40 patients in group A and 50 patients in group B). At POD7, the incidence of PE, DVT and PESI was 17.50%, 5.00% and 102.14±9.87, respectively, in group A. And 8.00%, 8.00% and 97.00±4.24, respectively, in group B. There were no significant differences between two groups (all P values were >0.05). There were no significant differences of HGB, PLT, D-dimer and P/F between two groups at the 7th day post operation (all P value >0.05). Conclusions: LMWH combined mechanical prophylaxis did not significant reduced the rate of VTE in thoracotomy cancer patients.

To investigate the value of an intravoxel incoherent motion (IVIM) diffusion model for discriminating malignant versus benign mediastinal lymph nodes (MLN). Thirty-five subjects with enlarged MLN were scanned at 1.5 Tesla. Diffusion-weighted imaging was performed with eight b-values. IVIM parameters D, D*, and f, as well as apparent diffusion coefficient (ADC) from a mono-exponential model were obtained. 91 nodes (49 malignant and 42 benign) were analysed with pathologic (n=90) or radiologic (n=1) confirmations. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance. The mean values of D, ADC, and f for the malignant group were significantly lower than those for the benign group (p

Background The aim of this study was to explore whether spectral computed tomography (CT) imaging parameters are associated with PD‐L1 expression of lung adenocarcinoma. Methods Spectral CT imaging parameters (iodine concentrations [IC] of lesion in arterial phase [ICLa] and venous phase [ICLv], normalized IC [NICa/NICv]‐normalized to the IC in the aorta, slope of the spectral HU curve [λHUa/λHUv] and enhanced monochromatic CT number [CT40keVa/v, CT70keVa/v] on 40 and 70 keV images) were analyzed in 34 prospectively enrolled lung adenocarcinoma patients with common molecular pathological markers including PD‐L1 expression detected with immunohistochemistry. Patients were divided into two groups: positive PD‐L1 expression and negative PD‐L1 expression groups. Two‐sample Mann‐Whitney U test was used to test the difference of spectral CT imaging parameters between the two groups. Results The CT40keVa (127.03 ± 37.92 vs. −54.69 ± 262.04), CT40keVv (124.39 ± 34.71 vs. −45.73 ± 238.97), CT70keVa (49.56 ± 11.76 vs. −136.51 ± 237.08) and CT70keVv (46.13 ± 15.81 vs. −133.10 ± 230.72) parameters in the positive PD‐L1 expression group of lung adenocarcinoma were significantly higher than the negative PD‐L1 expression group (all P 0.05). Conclusion CT40keVa, CT40keVv, CT70keVa and CT70keVv were increased in positive PD‐L1 expression. These parameters may be used to distinguish the PD‐L1 expression state of lung adenocarcinoma.

ABCA1 -565C/T gene promoter variants have been associated with the severity of coronary artery disease in Western populations. The purpose of our study was to investigate the association between the -565C/T gene polymorphism and coronary artery disease severity and cholesterol efflux in the Chinese Han population.A cohort of 298 acute coronary syndrome (ACS) patients and 541 healthy controls was genotyped using the highly sensitive ligase detection reaction. ABCA1 -565C/T genotype was correlated with the clinical features of 164 acute myocardial infarction (AMI) patients. Monocytes from patients with various -565C/T gene polymorphisms were isolated and differentiated into foam cells by coincubation with [(3)H]-labeled acetyl-low-density lipoprotein cholesterol. ABCA1 mRNA and protein expression levels were evaluated, as well as cellular cholesterol efflux.The frequency of the TT genotype in the -565C/T polymorphism of ACS patients was significantly increased when compared with controls (0.211 vs. 0.162, p0.05). The TT genotype, but not the CT or CC genotypes, in the -565C/T gene polymorphism correlated with the severity of the coronary lesion observed in AMI patients. Patients with the TT homozygote genotype also exhibited significantly lower cellular cholesterol efflux (TT [6.37%±0.554%]) levels than controls and also had the lowest levels of ABCA1 mRNA and protein expression among the group of variants. In contrast, cholesterol efflux levels in AMI patients with CT [11.35%±3.975%] and CC ([15.32%±6.293%]) genotypes were not significantly different from controls.Impaired ABCA1-mediated cholesterol efflux in macrophages may be associated with the severity of the coronary lesions in AMI patients with the TT genotype at the -565C/T gene polymorphism.

OBJECTIVE The aim of this study was to comprehensively analyze computed tomography features to improve the diagnostic accuracy of visceral pleural invasion of peripheral non-small cell lung cancer. METHODS The computed tomography features of 205 non-small cell lung cancer patients were retrospectively studied. The lesion's relation to the pleura was classified into 5 grades. A multivariate logistic regression analysis was conducted to identify independent factors predicting pleural invasion. RESULTS The multivariate logistic regression analysis showed that sex (odds ratio [OR], 1.822; P = 0.080), pleural indentation (OR, 4.111; P < 0.001), tumor density (OR, 2.735; P = 0.008), and distance between the lesion and pleura (OR, 1.981; P = 0.048) were independent predictors of pleural invasion. A patient with a score of 10.6 had an 80% risk of pleural invasion, whereas a score lower than 2 was associated with a lower (20%) risk of pleural invasion. CONCLUSIONS Comprehensive consideration of these factors of pleural indentation, sex, tumor density, and distance between the lesion and pleura might improve the diagnosis of pleural invasion.

Objective Both decreased glomerular filtration rate (GFR) and arterial stiffness were considered as risk factors for atherosclerosis. Previous studies have suggested the association between central arterial stiffness and the degree of GFR loss. Whether decreased GFR contributes to peripheral artery stiffness remains controversial. Moreover, data analyzed from a cohort of Chinese women are rare. Our aim was to explore the relationship between GFR and regional arterial stiffness in Chinese women. Methods In this cross-sectional study, we randomly recruited 1131 adult women residents with GFR ≥ 60 mL/min per 1.73 m 2 estimated by the Chinese Modification of Diet in Renal Disease equation from three large communities. Central and peripheral arterial stiffness were estimated simultaneously by measuring carotid-femoral pulse wave velocity (PWVcf) and carotid-radial PWV (PWVcr) using a validated automatic device. Augmentation Index at heart rate 75 beats/minutes (AIx-75) was measured by pulse wave analysis as a composite parameter reflecting both large and distal arterial properties. Results The mean estimated GFR (eGFR) of the study group was 100.05 ± 23.26 mL/minute per 1.73 m 2 . Subjects were grouped by tertiles of eGFR level. PWVcf and AIx-75 increased ongoing from the top to the bottom eGFR tertile, while the values of PWVcr were comparable. Both univariate Pearson correlations and multiple stepwise regression analyses showed that eGFR significantly correlated to PWVcf, but not to PWVcr and AIx-75. Conclusions In Chinese women with normal to mildly impaired renal function, decreased eGFR affected carotid-to-femoral rather than carotid-to-radial stiffening. This provides rational to conduct future prospective studies to investigate predictors of atherosclerosis in this population. J Geriatr Cardiol 2012; 9: 158−165. doi: 10.3724/SP.J.1263.2012.03051

The role of the lipoprotein-associated phospholipase A(2) gene (PLA2G7) in atherosclerosis remains controversial. We investigated the frequency of single-nucleotide polymorphisms (SNPs) of PLA2G7 (rs16874954 and rs1051931) and their association with coronary artery disease (CAD) in a cohort of CAD patients (n= 806) and age-matched healthy controls (n= 482) in the Chinese Han population. The VF and FF genotype of rs16874954 was significantly more frequent in the CAD patients (13.5%) than in the controls (9.3%, P= 0.024). The association remained after adjustment for age, gender, body mass index, smoking status, history of diabetes, positive family history of CAD, high-density lipoprotein cholesterol, and triglyceride (OR = 1.922; 95% CI [1.146-3.224]; P= 0.013). There was no significant difference in the frequency of any genotype of rs1051931 between the two groups. However, the frequency of the allele V379 was significantly greater in CAD patients with a history of myocardial infarction (MI) than in those without a history of MI (18.7% and 14.8%, P= 0.038). We conclude that there is significant association between the rs16874954 mutation and CAD in the Chinese Han population. The expression of rs1051931 variant in CAD patients may entail increased risk of MI.

The purpose of this article is to investigate whether apparent diffusion coefficient (ADC) might be used as a universal biomarker for response evaluation in different tumors.Twenty-one patients with lung cancer, 12 patients with esophageal cancer, 19 patients with liver metastases, 24 patients with gastric cancer, and 26 patients with rectal cancer were recruited to the study. Percentage changes in the ADC and changes in the size of responding and nonresponding lesions of different tumors after treatment were analyzed using repeated measures analysis of variance.There was no significant difference among the percentage ADC changes of different tumors (F = 1.57; p = 0.192). Clear differences were seen in the percentage ADC changes between responding and nonresponding tumors (F = 21.62; p0.001), which were significant at every time point after the start of treatment (early time point, F = 19.75 and p0.001; middle time point, F = 11.23 and p = 0.001; and later time point, F = 15.98 and p0.001). The percentage size changes after treatment between responding and nonresponding tumors were significantly different (F = 19.38; p0.001). However, at the early time point after treatment, the difference was not statistically significant (F = 0.02; p = 0.894).The ADC changes correlated with treatment response in five types of body tumor but were independent of the tumor's location. Early increases in ADC during treatment indicate good response to treatment. ADC change is a promising biomarker for detecting therapeutic responses at an early stage that could be widely used.

Eur J Clin Invest 2011; 41 (9): 929–936 Abstract Background Some cardiovascular risk factors such as age, hypertension and diabetes have been confirmed to be positively correlated with arterial stiffness. However, the relationship between serum lipids and arterial stiffness is incompletely understood. Recent studies have been far from conclusive and consistent data were not obtained. We investigated the relationship between serum lipids and pulse wave velocity (PWV) in community-dwelling individuals in Beijing, China. Methods This was a population-based, cross-sectional sample of adults (n = 2375; 48·1% men; age range, 40–96 years) from two communities in Beijing. A questionnaire was used for the risk factors of arterial stiffness. Anthropometry, blood pressure and heart rate were measured. Values of fasting plasma glucose (FPG), serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and uric acid were measured. Carotid–femoral PWV (cfPWV) and carotid–radial PWV (crPWV) were assessed non-invasively. Results Carotid–femoral pulse wave velocity was significantly positively related to TC (r = 0·221; P

The usefulness of diffusion-weighted magnetic resonance (MR) imaging (DWI) for differentiating central lung cancer from postobstructive lobar collapse (POC) was investigated. Thirty-three cases suspected of lung cancer and POC on chest bolus computed tomography (CT) underwent thoracic MR imaging examinations. MR examinations were performed using a 1.5-T clinical scanner. Scanning sequences were T1-weighted imaging, T2-weighted imaging (T2WI) and DWI with b=0, 500 s/mm(2), four excitations and segmented breath-holding. The densities and signals of cancer and postobstructive collapsed lung were compared on bolus-enhanced CT, T2W and DW images. Statistical analyses were performed with chi-square test, paired t-test, non-parameter test and kappa statistics. Differentiation between cancer and POC was possible on bolus CT, T2W and DW images in 14, 21 and 26 patients, respectively. Eight cases that were impossible to differentiate on T2W images were distinguishable on DWI, demonstrating that DWI is complementary to T2WI. Using a combination of T2W and DW images, 88% (29/33) of cases were differentiated on MR imaging. Thus, a combination of T2W and DW imaging is superior to bolus-CT or T2WI alone. The contrast-to-noise ratio of DWI was significantly higher than that of T2WI. Agreement between two independent observers on the differential ability of lung cancer and POC was higher for DWI (kappa=0.474) than for T2WI (kappa=0.339). The degree of consolidation around the cancer was negatively correlated with the degree of artifact and degree of deformation. It is feasible to use DWI to differentiate lung cancer from POC. DWI played a role in confirming and providing complementary information to that obtained from T2WI. Our data indicate that using a combination of the two scanned sequences was the best means of distinguishing between lung cancer and POC.

It has been more than one hundred years since the X-ray was discovered by W. K. Roentgen in 1895. In this period, the science of radiology has experienced tremendous development. By providing a more direct and objective way to explore the status of diseases, radiology is now acting as an indispensable part of clinical practice, especially in cancers which have increasing incidences and are life-threatening. Radiology plays an important role in all aspects, from early detection and diagnosis to treatment monitoring, efficacy evaluation and recurrence approach. When the routine imaging methods have shown their limitations under the rapid development of modern medicine, molecular imaging began to enter this area with specialities in exploring the essence of diseases on molecular and cellular levels. In this chapter, we focus on the clinical practice of tumors. Current applications and prospects of molecular imaging in this area will be discussed from various aspects.

The aim of this study was to investigate the performance of monochromatic images of spectral computed tomographic (CT) in the visualization of the pancreatic arteries compared with polychromatic CT images. We conducted a case–control study in a group of 26 consecutive patients with monochromatic CT and contrasted the results against a control group of 26 consecutive patients with polychromatic CT. The CNR (contrast-to-noise ratio), SIR (signal intensity ratio), SNR (signal to noise ratio), and image noise were measured. A 5-score classification system was used to evaluate the branch order of pancreatic arteries. The course of pancreatic arteries was compared. Compared with polychromatic images, the CNR, SIR, and SNR obtained by monochromatic images were increased by 64.74%, 23.99%, and 39.50%. Branch visualization of PSPDA (posterior superior pancreaticoduodenal artery), ASPDA (anterior superior pancreaticoduodenal artery), and DPA (dorsal pancreatic artery) was better at monochromatic images than at polychromatic images. The display rate was significantly better in monochromatic images for the second and third segments of PSPDA, total course of ASPDA, and artery of uncinate process. Compared with polychromatic images, monochromatic images can improve the visualization of pancreatic arteries.

The objective of this study was to compare the image quality and radiation dose of chest CT images reconstructed with a blend of adaptive statistical iterative reconstruction (ASIR) and filtered back-projection (FBP) with images generated using conventional FBP.Patients with chest CT re-examinations were alternately assigned to two scanners with different reconstruction techniques. The study groups included noise index (NI) 11 with 30% ASIR (A30), NI 13 with 40% ASIR (A40), NI 15 with 50% ASIR (A50) and NI 17 with 60% ASIR (A60), sequentially changed every 2 months. The control images were obtained using FBP and NI 11. All acquisitions were performed with automatic dose modulation. Paired t-test and non-parameter test were applied to compare the difference.The radiation doses were significantly lower in the examinations that used ASIR (p0.001). The mean dose reduction rate was 27.7%, 45.2%, 57.1% and 71.8% for Groups A30, A40, A50 and A60, respectively. The image quality of Groups A30-A50 was not inferior to that of the control examinations. The image noise of Group A60 was greater and subjective image quality was inferior to that of the control.ASIR enabled the use of a higher NI with automatic dose modulation. With 50% ASIR and a NI of 15, the effective radiation dose was reduced by 57%, without compromising image quality.

To prospectively investigate the use of the apparent diffusion coefficient (ADC) as an early response indicator in patients with gastrointestinal stromal tumors (GISTs) treated with imatinib mesylate.This study was approved by the institutional review board and written informed consent was obtained from all patients. Diffusion-weighted magnetic resonance (MR) imaging was performed in 32 patients with GISTs before and 1, 4, and 12 weeks after treatment with a tyrosine kinase inhibitor, imatinib mesylate. The measurable lesions were classified as having responded well or poorly according to size alterations at clinical evaluation following the first round of treatment (3 months). A linear mixed-effects model was applied to analyze changes in the ADCs of tumors during treatment and to compare the variation and slopes of the time-dependent ADC curves between the good- and poor-response groups.There were 56 lesions in the good-response group and 35 in the poor-response group. An early (1 week after therapy) noticeable and statistically significant (P.001) increase in the ADC was observed in the good-response group (median ADC increase, 44.8%) but not in the poor-response group (median ADC increase, 1.5%). The time-dependent ADC variation was significantly different between the good- and poor-response groups, with a sharper median ADC increase displayed in the former (week 1: 44.8% vs 1.5%; week 4: 80.4% vs 7.8%; week 12: 89.6% vs 16.7%; F = 25.78, P.001). The largest difference in the weekly percentage increase in ADC between the good- and poor-response groups was observed at 1 week after therapy (week 0-1: 44.8% vs 1.5%; week 1-4: 7.0% vs 2.8%; week 4-12: 1.6% vs 0.7%). The pretherapy mean ADC (± standard deviation) of lesions in the good-response group (1.06 [×10(-3) mm(2)/sec] ± 0.27) was significantly lower than that in the poor-response group (1.24 [×10(-3) mm(2)/sec] ± 0.32) (F = 8.34, P = .005).Comparatively low pretherapy ADC and marked ADC increase at 1 week after therapy is associated with good response to imatinib mesylate in patients with GISTs.