A detection model based on Gramian angular field(GAF)and parallel KConvNeXt network is proposed for accurately detecting the abnormal conditions caused by sample needle blockage in the sampling system during the sampling,thus improving the testing accuracy and detection efficiency of automated biochemical analyzers.GAF-based method is employed to transform the time series of one-dimensional pressure signals into two-dimensional image representations.Subsequently,an improved attention mechanism integrated with a parallel dual-channel KConvNeXt network is used to classify the pressure signals,and achieves a final classification accuracy of 94.58%.The experimental results show that the proposed method can effectively capture the key characteristics of the pressure signals,offering an efficient solution for the anomalous pressure detection in biochemical analyzer sampling system and exhibiting important practical significance.

A detection model based on Gramian angular field(GAF)and parallel KConvNeXt network is proposed for accurately detecting the abnormal conditions caused by sample needle blockage in the sampling system during the sampling,thus improving the testing accuracy and detection efficiency of automated biochemical analyzers.GAF-based method is employed to transform the time series of one-dimensional pressure signals into two-dimensional image representations.Subsequently,an improved attention mechanism integrated with a parallel dual-channel KConvNeXt network is used to classify the pressure signals,and achieves a final classification accuracy of 94.58%.The experimental results show that the proposed method can effectively capture the key characteristics of the pressure signals,offering an efficient solution for the anomalous pressure detection in biochemical analyzer sampling system and exhibiting important practical significance.

OBJECTIVETo evaluate the diagnostic value of 3.0T high-resolution MRI in mesorectal lymph node metastasis of rectal cancer.

METHODSThe images and postoperative pathological data of patients with pathologically diagnosed rectal cancer who underwent prospective 3.0T two dimensional high-resolution MRI rectal examinations and surgery within two weeks after MRI examination at the First Affiliated Hospital, Sun Yat-sen University from November 2015 to November 2016 were retrospectively collected. Patients who received preoperative neoadjuvant therapy and those who did not undergo operation after MRI examination were excluded. The MRI sequences included high-resolution sagittal, coronal and oblique axial T2 weighted image (T2WI) (repetition time/echo time, 3000-4000 ms/77-87 ms; slice thickness/gap, 3 mm/0 mm; field of view, 18-22 cm). Two abdominal MRI radiologists independently assessed the morphology, margin, signal of all visible mesorectal nodes, measured their minor axes (three times for each radiologist) and gave estimation of the malignancy. The criteria of metastatic nodes on high-resolution MRI T2WI were nodes with irregular shape, ill-defined border and/or heterogeneous signal. The results of MRI diagnosis were compared with postoperative pathology. The sensitivity, specificity, accuracy, positive predictive value(PPV) and negative predictive value(NPV) of mesorectal nodes and nodes with different short-axis diameter ranges were calculated to evaluate the diagnostic efficiency of high-resolution MRI. Kappa statistics was used to evaluate the agreement for per node and for per patient between high-resolution MRI and pathological results. A Kappa value of 0-0.20 indicated poor agreement; 0.21-0.40 fair agreement; 0.41-0.60 moderate agreement; 0.61-0.80 good agreement; and 0.81-1.00 excellent agreement.

RESULTSA total of 81 patients were enrolled in the retrospective cohort study, including 50 males and 31 females with age of (59.3±11.1) years. Histopathology showed 1 case of well differentiated adenocarcinoma, 63 of moderately differentiated adenocarcinoma, 9 of moderately to poorly differentiated adenocarcinoma, 2 of poorly differentiated adenocarcinoma, 3 of mucinous adenocarcinoma and 3 of tubulovillous adenocarcinoma. Histopathological staging showed 2 cases in T1 stage, 20 in T2 stage, 45 in T3 stage and 14 in T4 stage; 34 in N0 stage, 40 in N1 stage and 7 in N2 stage; 76 in M0 stage and 5 in M1 stage. A total of 377 nodes were included in the node-by-node evaluation, of which 168 (44.6%) nodes were metastatic from 58.0% (47/81) patients. The median short-axis diameter was 5.4(2.4-18.6) mm in metastatic nodes, which was significantly larger than 3.8 (2.0-8.7) mm in non-metastatic nodes[Z=10.586, P=0.000]. The sensitivity, specificity, accuracy, PPV and NPV were 74.4% (125/168), 94.7% (198/209), 85.7% (323/377), 91.9% (125/136) and 82.2% (198/241), respectively. The Kappa values between high-resolution MRI and histopathological diagnosis for node-by-node and patient-by-patient were 0.71 and 0.70 respectively, indicating good agreements. Fourteen nodes >10 mm were all metastatic. The results of high-resolution MRI for nodal status were consistent with the results of histopathological diagnosis, and the sensitivity, accuracy and PPV were all 100.0%. Among 124 nodes with short-axis diameter of 5-10 mm, 95 (76.6%) were metastatic, and the sensitivity, specificity, accuracy, PPV and NPV were 78.9% (75/95), 86.2% (25/29), 80.6% (100/124), 94.9% (75/79) and 55.6% (25/45), respectively. The agreement was fair (Kappa value 0.55) between high-resolution MRI and histopathological diagnosis. Among 239 nodes with short-axis diameter ≤5 mm, 59(24.7%) were metastatic, and the sensitivity, specificity, accuracy, PPV and NPV were 61.0% (36/59), 96.1%(173/180), 87.4%(209/239), 83.7%(36/43) and 88.3%(173/196), respectively. The agreement was good (Kappa value 0.63) between high-resolution MRI and histopathological diagnosis.

CONCLUSIONRectal high-resolution MRI has good diagnostic value for estimating metastatic mesorectal nodes by evaluating the morphology, margin and signal of nodes.

Aged ; Female ; Humans ; Lymph Nodes ; Lymphatic Metastasis ; diagnostic imaging ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neoplasm Staging ; Prospective Studies ; Rectal Neoplasms ; diagnostic imaging ; pathology ; Retrospective Studies ; Sensitivity and Specificity

Objective To explore the repeatability and consistency of MR intravoxel incoherent motion (IVIM) parameters of rectal cancers.Methods Routine high resolution rectal MR and IVIM sequence were performed on 128 patients with pathologically proved rectal cancers before treatment.IVIM maps were generated from two sets of b-values (group A:0,5,10,20,30,40,60,80,100,150,200,400,600 and 1000 s/mm2;group B:0,5,10,20,30,40,60,80,100,150,200,400,600,1000,1500 and 2000 s/mm2),and IVIM parameters (D,D* and f) were measured.Then IVIM parameters were measured again by the same observer three months later.The intra-class correlation coefficient (ICC) and Bland-Altman graph analysis were performed to explore the repeatability and consistency of IVIM parameters.Results The differences of IVIM parameters (D,D* and f) derived from the two sets of b-values were statistically different (all P＜0.001).ICC and 95％ confidence interval (CI) of D,D* and f was 0.968 (0.955,0.977),0.780 (0.688,0.845) and 0.957 (0.934,0.970),respectively.Bland-Altman analysis showed that the 95 ％ limits of agreement of D,D* and f was (10.8％,22.4％),(14.8％,61.9％) and (-45.3％,-10.2％),respectively.There was significant difference of D* between twice measurement by the same observer (P=0.001);ICC and 95％CI of D,D* and f was 0.826(0.670,0.908),0.678 (0.392,0.830) and 0.910 (0.830,0.952),respectively.Furthermore,Bland-Altman analysis showed that the 95％ limits of agreement of D,D* and f were (-15.3％,12.4％),(-39.6％,61.2％) and (-22.6％,22.9％),respectively.Conclusion Under the two different sets of b-values,all IVIM parameters of rectal cancers demonstrate good consistency.In addition,D and f value show good repeatability.

AIM:To investigate the perfusion parameters using dynamic contrast-enhanced magnetic resonance imaging ( DCE-MRI) in rectal cancer patients so as to explore its potential value in estimating the microvascular condition including perfusion and permeability .METHODS:The data of 38 rectal cancer patients examined with DCE-MRI was ret-rospectively analyzed .The perfusion parameters of carcinoma and normal rectal wall in each case were calculated , inclu-ding volume transfer constant (Ktrans), rate constant of back flux (Kep), extravascular extracellular space fractional volume (Ve) and initial area under curve (iAUC).The mean values of tumor and normal rectal wall , mucinous and nonmucinous carcinoma, poorly and moderately-to-well differentiated carcinoma , case with or without lymph node metastasis were com-pared.RESULTS:All the parameters of rectal cancer were higher than normal rectal wall (P<0.01).No significant difference was found between poorly and moderately-to-well differentiated carcinoma in terms of K trans, Kep and Ve, neither was the case with or without lymph node metastasis .The cases with lymph node metastasis had lower iAUC than those with-out (P<0.05).CONCLUSION:Quantitative perfusion DCE-MRI answered the microvascular perfusion and permeability change of rectal cancer compared with normal rectal wall , besides it could be used to distinguish between mucinous and nonmucinous carcinoma , which demonstrated its value in the evaluation of rectal cancer .However , it should not be recom-mended to predict the degrees of tumor cell differentiation and lymph node metastasis just according to the perfusion param -eters.

Objective To study the value of dual-phase enhanced multi-slice computed tomography (MSCT)scan in combination with the reconstruction technique for distinguishing gallbladder adenomyomatosis (GBA)from gallbladder cancer.Methods We ret-rospectively reviewed the CT features (including dual-phase and reconstructed images)of 36 patients with GBA (Group A,1 6 pa-tients)or gallbladder cancer (Group B,20 patients)proved by pathology.Fisher exact test was used to compare the CT findings be-tween the two groups.Results The occurrence rates of RAS,gallbladder wall smoothing,clear gallbladder border,uniform en-hancement of serous layer and thickening of the gallbladder wall were statistically significantly different between Group A and B. When using the Rokitansky-Aschoff sinuses as a parameter for the differential diagnosis of the two groups,the diagnostic accuracy reached to 92.85%.Conclusion Dual-phase enhanced MSCT scan in combination with the reconstruction technique is a valuable ima-ging technique for distinguishing GBA from gallbladder cancer.