Assessment of kidney function in chronic kidney disease by combining diffusion tensor imaging and total kidney volume.

OBJECTIVE: This study aimed to investigate the value and feasibility of combining fractional anisotropy (FA) values from diffusion tensor imaging (DTI) and total kidney volume (TKV) for the assessment of kidney function in chronic kidney disease (CKD). MATERIALS AND METHODS: Fifty-one patients were included in this study. All MRI examinations were performed with a 3.0 T scanner. DTI was used to measure FA values, and TKV was obtained from DTI and T2-weighted imaging (T2WI). Patients were divided into three groups (mild, moderate, severe) according to eGFR, which was calculated with serum creatinine. Differences in the FA values of the cortex and medulla were analysed among the three groups, and the relationships of FA values, TKV, and the product of the FA values and TKV with eGFR were analysed. Receiver operating characteristic (ROC) curve analysis was used to compare the diagnostic efficiency of the FA values, TKV, and the product of the FA values and TKV for kidney function in different CKD stages. RESULTS: Medullary FA values (m-FA), TKV, and the product of the m-FA values and TKV (m-FA-TKV) were significantly correlated with eGFR (r = 0.653, 0.685, and 0.797, respectively; all P < 0.001). ROC curve analysis showed that m-FA-TKV exhibited better diagnostic performance than m-FA values (P = 0.022). CONCLUSION: m-FA-TKV obtained by DTI significantly improves the accuracy of kidney function assessment in CKD patients.

Peri-thrombus vascular hyperintensity sign: detection of intracranial thrombus location and length in acute ischemic stroke.

PURPOSE: The aim of the study was to investigate the diagnostic accuracy of peri-thrombus vascular hyperintensity sign (PVHS) on three-dimensional (3D) black-blood (BB) contrast-enhanced MRI for the detection of intracranial thrombus location and length in acute ischemic stroke (AIS) patients. MATERIALS AND METHODS: Consecutive AIS patients who underwent MRI including 3D BB contrast-enhanced MRI sequence within 8 h of clinical onset were prospectively evaluated. Two readers independently reviewed the 3D BB contrast-enhanced MRI data to assess the presence and location of PVHS. Findings were compared with those of contrast-enhanced MR angiography (CE-MRA) as the reference standard. RESULTS: The PVHS was identified in 49% (63/129) of AIS patients with good agreement. The PVHS had 100% specificity, 88% negative predictive value, 89% sensitivity, and 100% positive predictive value for detection of acute arterial occlusions. Eight patients showed discordant thrombus locations between 3D BB contrast-enhanced MRI and CE-MRA. Median thrombus length in patients with complete occlusion was 9.61 mm. CONCLUSION: The PVHS on 3D BB contrast-enhanced MRI is a highly specific tool for evaluating the location and length of a thrombus in AIS patients.

Penumbra-based radiomics signature as prognostic biomarkers for thrombolysis of acute ischemic stroke patients: a multicenter cohort study.

BACKGROUND AND PURPOSE: This study aimed at developing a radiomics signature (R score) as prognostic biomarkers based on penumbra quantification and to validate the radiomics nomogram to predict the clinical outcomes for thrombolysis for acute ischemic stroke (AIS) patients. METHODS: In total, 168 patients collected from seven centers were retrospectively included. A score of mismatch was defined as MIS. Based on a short-term clinical label, 456 radiomics features were evaluated with feature selection methods. R score was constructed with the selected features. To compare the predictive capabilities of the clinical factors, MIS, and R score, three nomograms were developed and evaluated, according to the short-term clinical assessment on day 7. Finally, the radiomics nomogram was validated by predicting the 3-month clinical outcomes of AIS patients, in an external cohort. RESULTS: R scores were found to be significantly higher in patients with favorable clinical outcomes in both training and validation datasets. The predictive value of the radiomics nomogram estimating favorable clinical outcomes was modest, with a concordance index (C-index) of 0.695 [95% confidence interval (CI) 0.667-0.723) in an external validation dataset. In addition, the area under curve (AUC) of the radiomics nomogram predicting favorable clinical outcome reached 0.886 (95% CI 0.809-0.963) on day 7 and 0.777 (95% CI 0.666-0.888) at 3 months. CONCLUSIONS: The radiomics signature is an independent biomarker for estimating the clinical outcomes in AIS patients. By improving the individualized prediction of the clinical outcome for AIS patients 3 months after onset, the radiomics nomogram adds more value to the current clinical decision-making process.

A Deep Learning-Based Radiomics Model for Differentiating Benign and Malignant Renal Tumors.

OBJECTIVES: To investigate the effect of transfer learning on computed tomography (CT) images for the benign and malignant classification on renal tumors and to attempt to improve the classification accuracy by building patient-level models. METHODS: One hundred ninety-two cases of renal tumors were collected and identified by pathologic diagnosis within 15 days after enhanced CT examination (66% male, 70% malignant renal tumors, average age of 62.27 ±â€¯12.26 years). The InceptionV3 model pretrained by the ImageNet dataset was cross-trained to perform this classification. Five image-level models were established for each of the Slice, region of interest (ROI), and rectangular box region (RBR) datasets. Then, two patient-level models were built based on the optimal image-level models. The network's performance was evaluated through analysis of the receiver operating characteristic (ROC) and five-fold cross-validation. RESULTS: In the image-level models, the test results of model trained on the Slice dataset [accuracy (ACC) = 0.69 and Matthews correlation coefficient (MCC) = 0.45] were the worst. The corresponding results on the ROI dataset (ACC = 0.97 and MCC = 0.93) were slightly better than those on the RBR dataset (ACC = 0.93 and MCC = 0.85) when freezing the weights before the mixed6 layer. Compared with the image-level models, both patient-level models could discriminate better (ACC increased by 2%-5%) on the RBR and Slice datasets. CONCLUSIONS: Deep learning can be used to classify benign and malignant renal tumors from CT images. Our patient-level models could benefit from 3D data to improve the accuracy.

Development and validation of a penumbra-based predictive model for thrombolysis outcome in acute ischemic stroke patients.

The use of thrombolysis in acute ischemic stroke is restricted to a small proportion of patients because of the rigid 4·5-h window. With advanced imaging-based patient selection strategy, rescuing penumbra is critical to improving clinical outcomes. In this study, we included 155 acute ischemic stroke patients (84 patients in training dataset, age from 43 to 80, 59 males; 71 patients in validation dataset, age from 36 to 80, 45 males) who underwent MR scan within the first 9-h after onset, from 7 independent centers. Based on the mismatch concept, penumbra and core area were identified and quantitatively analyzed. Moreover, predictive models were developed and validated to provide an approach for identifying patients who may benefit from thrombolytic therapy. Predictive models were constructed, and corresponding areas under the curve (AUC) were calculated to explore their performances in predicting clinical outcomes. Additionally, the models were validated using an independent dataset both on Day-7 and Day-90. Significant correlations were detected between the mismatch ratio and clinical assessments in both the training and validation datasets. Treatment option, baseline systolic blood pressure, National Institutes of Health Stroke Scale score, mismatch ratio, and three regional radiological parameters were selected as biomarkers in the combined model to predict clinical outcomes of acute ischemic stroke patients. With the external validation, this predictive model reached AUCs of 0·863 as short-term validation and 0·778 as long-term validation. This model has the potential to provide quantitative biomarkers that aid patient selection for thrombolysis either within or beyond the current time window.

Combined Direct and Indirect CT Venography (Combined CTV) in Detecting Lower Extremity Deep Vein Thrombosis.

This study aimed to evaluate the diagnostic accuracy of combined direct and indirect CT venography (combined CTV) in the detection of lower extremity deep vein thrombosis (LEDVT). The institutional review board approved the study protocol, and patients or qualifying family members provided informed consent. A total of 96 consecutive patients undergoing combined CTV were prospectively enrolled. A combined examination with digital subtraction angiography (DSA) plus duplex ultrasonography (US) was used as the criterion standard. Three observers were blinded to clinical, DSA, and US results, and they independently analyzed all combined CTV datasets. Interobserver agreement was expressed in terms of the Cohen k value for categorical variables. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of combined CTV in the detection of LEDVT were determined by using patient- and location-based evaluations. Of the 96 patients, DSA plus US revealed LEDVT in 125 segmental veins in 63 patients. Patient-based evaluation with combined CTV yielded an accuracy of 96.9% to 97.9%, a sensitivity of 95.2% to 96.8%, a specificity of 100% to 100%, a PPV of 100% to 100%, and an NPV of 91.7% to 94.3% in the detection of LEDVT. Location-based evaluation yielded similar results. Through combined direct and indirect CTV, patients obtained a combined CT angiogram on the diseased limb and an indirect CT angiogram on the opposite side. The image quality of combined CTV was superior to an indirect venogram. Combined CTV shows promising diagnostic accuracy in the detection of LEDVT with 3-dimensional modeling of the lower limb venous system.

Low-Voltage, High-Pitch Computerized Tomography Angiography of the Infrarenal Aorta and Lower Extremity Vessels: Assessment of Radiation Dose, Image Quality With Hybrid Iterative Reconstruction, and Efficacy of Test Injection Using a Monitoring Scan at Knee Level.

OBJECTIVES: Our aim was to assess image quality and radiation dose of low-voltage high-pitch computed tomography angiography of the infrarenal aorta and lower extremities and evaluate the efficacy of test injection technique using a monitoring scan at knee level. METHODS: A total of 60 patients with suspected peripheral arterial disease were divided into 2 groups: group 1 (30 patients, 80 kVp, high pitch [3.2], and hybrid iterative reconstruction [sinogram-affirmed iterative reconstruction]) and group 2 (30 patients, 120 kVp, low pitch [1.0], and filtered back projection reconstruction). The test injection technique at knee level was used to determine the scan delay time in group 1. The image quality and radiation exposure were compared. RESULTS: There were significant differences between the 2 groups in mean (SD) arterial attenuation (80 vs 120 kVp: 507.78 [103.01] vs 317.54 [62.03] Hounsfield units, P < 0.001), mean (SD) signal-to-noise ratio (51.04 [20.29] vs 34.66 [9.94], P < 0.001), and contrast-to-noise ratio (44.83 [17.93] vs 28.26 [9.60], P < 0.001). No difference in subjective image quality was found between the 2 groups (all P > 0.05). The imaging time was significantly shorter in group 1 (2.70 [0.11] vs 14.65 [0.90s], P < 0.001). The mean (SD) effective dose was significantly lower in the 80 kVp group (0.76 [0.06] vs 4.29 [0.63] mSv, P < 0.001). CONCLUSIONS: The 80-kVp high-pitch computed tomography angiography of the lower limbs using sinogram-affirmed iterative reconstruction yields reduction of radiation exposure as well as obtains acceptable image quality if acquisition protocols are used in conjunction with the test injection technique using monitoring scan at knee level to determine the delay time.

Preliminary study correlating CX3CL1/CX3CR1 expression with gastric carcinoma and gastric carcinoma perineural invasion.

AIM: To study the relationship between the CX3CL1 chemokine, its receptor CX3CR1, and gastric carcinoma/gastric carcinoma perineural invasion (PNI). METHODS: Thirty cases of gastric carcinoma were surgically resected (radical resection or palliative resection) between February 2012 and July 2012. Tumour and tumour-adjacent tissues were evaluated for the presence of CX3CL1 (ELISA) and CX3CR1 (immunohistochemistry and Western blotting) in an effort to analyse the relationship between CX3CL1/CX3CR1 and gastric carcinoma/gastric carcinoma PNI. RESULTS: Of these 30 cases, 14 were PNI-positive (46.7%). No significant differences in CX3CL and CX3CR1 expression in tumour-adjacent tissues were found between the PNI positive and negative groups. Expression levels of CX3CL and CX3CR1 in tumour tissues were significantly higher than those in adjacent tissues (P < 0.01), and were significantly higher in tumour tissues from the PNI-positive group compared to the PNI-negative group (P < 0.01). CONCLUSION: CX3CL1/CX3CR1 expression may be associated with the occurrence and development of gastric carcinoma as well as gastric carcinoma PNI.

A preliminary study on correlations of triple-phase multi-slice CT scan with histological differentiation and intratumoral microvascular/lymphatic invasion in gastric cancer.

BACKGROUND: Many studies have shown that cancer cell differentiation and microvascular invasion play a principle role in cancer progression and metastasis, and non-invasive imaging techniques such as CT, MRI and US assessing the differentiation and the surgical resectibility and the prognosis of cancers are now of great importance. This study aimed to explore the correlation of triple-phase multi-slice CT scan with the histological differentiation and intratumor microvascular/lymphatic invasion of progressive gastric cancer. METHODS: The present study included 64 patients with gastric cancer, all of whom underwent routinal and dual-phase contrast enhancement multi-slice CT examinations of the upper abdomen before surgery. The post-operative specimens were used for determination of histological differentiation, cancer cell invasion of intratumoral microvascular/lymphatic vessel identified by CD34 and D2-40 expression. Correlations between contrast enhancement ratio (CER) of triple-phase multi-slice CT scan in gastric cancer and histological differentiation as well as intratumoral microvascular/lymphatic invasion were compared and analyzed. RESULTS: There was a significant correlation between CER of triple-phase CT scan in gastric cancer and tumor histological differentiation (P < 0.05). CER of the arterial phase in gastric cancer with intratumoral microvascular invasion was significantly higher than that without invasion (0.61 ± 0.28 vs. 0.46 ± 0.14, P < 0.05); CER of the arterial-parenchymal phase was significantly lower in gastric cancer with intratumoral microvascular invasion than that without invasion (1.81 ± 0.39 vs. 2.28 ± 0.80, P < 0.05). However, CER of the parenchymal phase in gastric cancer with intratumoral lymphatic invasion was significantly higher than that without invasion (1.25 ± 0.57 vs. 1.00 ± 0.35, P < 0.05). CONCLUSIONS: CER of triple-phase multi-slice CT scan in gastric cancer is closely correlated with intratumoral microvascular and lymphatic invasion, and also could be used as a marker for histological differentiation.

[Associations of triple-phase enhancement multi-slice CT scan with histological differentiation and lymphovascular invasion in gastric cancer].

OBJECTIVE: To explore the associations of triple-phase enhancement multi-slice CT scan with histological differentiation and lymphovascular invasion in advanced gastric cancer. METHODS: Patients with gastric cancer undergoing surgical resection between January 2006 and December 2009 were included, all of whom underwent routine and two-phase contrast enhancement multi-slice CT examinations of the upper abdomen before surgery. Patients with incomplete data were excluded. Postoperative specimens were used for evaluation of histological differentiation, microscopic lymphovascular invasion, and CD34 and D2-40 expression. Associations between contrast enhancement ratio (CER) of triple-phase multi-slice CT scan and differentiation as well as lymphovascular invasion were analyzed. RESULTS: A total of 64 patients were included. There were significant associations between CER and tumor differentiation (P<0.05). Compared to those without microvascular invasion, CER of the arterial phase in gastric cancer with microvascular invasion was significantly higher (0.61±0.28 vs. 0.46±0.14, P<0.05), and that of the arterial-parenchymal phase was significantly lower(1.81±0.39 vs. 2.28±0.80, P<0.05). However, gastric cancers with lymphatic invasion were associated with significantly higher CER of the parenchymal phase than their counterparts(1.25±0.57 vs. 1.00±0.35, P<0.05). CONCLUSION: CER of triple-phase multi-slice CT scan can reveal the differentiation of gastric cancer and is associated with microvascular and lymphatic invasion.

Multi-slice CT contrast-enhanced presentations of advanced gastric cancer: associations with histo-differentiation and expression of p53 and P-glycoprotein.

BACKGROUND: This study aimed to investigate multi-slice CT contrast-enhanced presentation of gastric cancer and its correlation with histo-differentiation and p53 and P-glycoprotein (P-gp) expression. METHODS: Sixty-six patients with gastric cancer in the present study underwent a multi-slice CT preoperative routine and dual-phase contrast-enhanced examination of the upper abdomen; postoperative specimens were used to determine histo-differentiation and the expression of p53 and P-gp. The correlation of multi-slice CT contrast-enhanced presentation with histo-differentiation and expression of p53 and P-gp was analyzed. RESULTS: The dual-phase contrast-enhanced ratio (CER) was not correlated with the histo-differentiation of gastric cancer (P > 0.05). Positive expression of p53 and P-gp was significantly higher in the cases of layered or heterogeneous enhancement than in the cases of homogenous enhancement (P < 0.05). Positive expression of p53 was also correlated with the arterial phase CER, tumor size and lymph node metastasis (P < 0.05), but not with infiltration thickness of the gastric wall, nor was it correlated with the portal phase CER (P > 0.05). Positive expression of P-gp was only correlated with the portal phase CER (P = 0.005). CONCLUSIONS: Differently enhanced pattern and CER of the arterial and portal phase in gastric cancer correlate with its different histo-differentiation and expression of p53 and P-gp respectively. In addition, tumor size and lymph node metastasis of gastric cancer relate to the expression of p53.

[Application of diffusion-weighted and perfusion magnetic resonance imaging in definition of the ischemic penumbra in hyperacute cerebral infarction].

OBJECTIVE: To investigate the value of diffusion-weighted imaging (DWI) and perfusion imaging (PI) in definition of the ischemic penumbra in hyperacute cerebral infarction. METHODS: (1) Animal study: Fifty-five SD rats were randomly divided into 5 groups of 10 rats. Nylon monofilament was inserted into the left middle cerebral artery (MCA) and immediately pulled out in 10 rats as controls (sham operation group or group A). The MCA of 40 rats was occluded by nylon monofilament for 30 minutes (group B), 60 minutes (group C), 180 minutes (group D), and 360 minutes (group E). Then all rats were examined by T(1)WI, T(2)WI, DWI, and PI. Apparent diffusion coefficient (ADC), regional cerebral blood volume (rCBV), relative cerebral blood flow (rCBF) and mean transit time (MTT) topographical maps were archived by the Workstation (GE SUN ADW3.0). The relative values of ADC, rCBV, rCBF, and MTT (ratios between the values of the occluded side and the opposite side) were calculated. The rats were killed and the cerebral infarction areas were stained by TTC (C(19)H(15)N(4)CI) and observed by light microscopy and electron microscopy. The results of microscopic examination were compared with the DWI results. (2) Clinical study: Forty-three patients, 24 males and 19 females,aged 68 years on average with acute stroke symptoms underwent MRI examination within 6 hours of symptom onset. T(1)WI, T(2)WI, DWI and PI were performed on all patients at the first MRI examination and T(2)WI was performed for follow up. The relevant parameters, including ADC, rCBV, rCBF and MTT were computed. The values of ADC, rCBV, rCBF and MTT within the lesions were compared to those at the normal sides and the ratio was calculated. The lesion volumes were measured in ADC map (as vDWI), MTT map (as vPI) and follow-up T(2)WI (as vCI). The differences between vDWI and vPI, and between vDWI and vCI were compared. RESULTS: (1) Animal study: In the control group DWI and PI showed no change in the signal intensity and no pathological change was found. Hyper-intensity signal was found in the T(2)WI in groups D and E. No abnormal signal was found in the T(1)WI in all groups. Abnormal signals were found in the MCA-supplying region in the DWI and PI of groups B, C, D, and E. The size of hyper-intensity signal in DWI along with the extension of occlusion time. TTC staining showed that the volume of unstained area was similar to that of hyper-intensity signal area in DWI image (t test, P > 0.05). PI showed a decrease of cerebral perfusion in the MCA-supplying region along with the extension of occlusion time. However, the size enlargement of occluded region was not as severe as shown by DWI along with the extension of occlusion time. The size of region with abnormal perfusion shown by PI was larger than that shown by DWI in groups B, C, and D. PI/DWI mismatch region, indicating the existence of ischemic penumbra zone, became gradually smaller along with the extension of occlusion time and almost disappeared 360 minutes after MCA occlusion. No significant change was found in the PI/DWI mismatch region by light microscope but slight swelling of mitochondrion and Golgi apparatus in neurons were observed by electron microscope. (2) Clinical study: The cases of 38 of the 43 patients were diagnosed as cerebral infarction by clinical and MRI follow-up examinations. The first MRI examination of these 38 cases showed no abnormal signal in T(1)WI and hyper-intensity signal in T(2)WI of 4 cases. The vPI was larger than vDWI in 31 cases and the vPI was equal to or smaller than the vDWI in 7 cases. Follow-up examination showed that vCI was larger than vDWI in 28 cases and vCI almost equaled to vDWI in 10 cases. Spearman correlation analysis showed a positive correlation between the volume of ischemic penumbra zone and that of infarction (r = 0.689, P < 0.001) which suggests that the volume change of ischemic penumbra zone influences the size of final infarction directly. CONCLUSION: Combination of DWI and PI clearly defines the ischemic penumbra in hyperacute stroke patient, thus laying, thus laying a basis for therapeutic intervention plan for stroke patients.