Artificial intelligence software for assessing brain ischemic penumbra/core infarction on computed tomography perfusion:A real-world accuracy study

BACKGROUND With the increasingly extensive application of artificial intelligence(AI)in medical systems,the accuracy of AI in medical diagnosis in the real world deserves attention and objective evaluation.AIM To investigate the accuracy of AI diagnostic software(Shukun)in assessing ischemic penumbra/core infarction in acute ischemic stroke patients due to large vessel occlusion.METHODS From November 2021 to March 2022,consecutive acute stroke patients with large vessel occlusion who underwent mechanical thrombectomy(MT)post-Shukun AI penumbra assessment were included.Computed tomography angiography(CTA)and perfusion exams were analyzed by AI,reviewed by senior neurointerventional experts.In the case of divergences among the three experts,discussions were held to reach a final conclusion.When the results of AI were inconsistent with the neurointerventional experts’diagnosis,the diagnosis by AI was considered inaccurate.RESULTS A total of 22 patients were included in the study.The vascular recanalization rate was 90.9%,and 63.6%of patients had modified Rankin scale scores of 0-2 at the 3-month follow-up.The computed tomography(CT)perfusion diagnosis by Shukun(AI)was confirmed to be invalid in 3 patients(inaccuracy rate:13.6%).CONCLUSION AI(Shukun)has limits in assessing ischemic penumbra.Integrating clinical and imaging data(CT,CTA,and even magnetic resonance imaging)is crucial for MT decision-making.

Computed tomography perfusion imaging as a potential imaging biomarker of colorectal cancer

Neovascularization was reported to arise early in the adenoma-carcinoma sequence in colorectal cancer(CRC),and the importance of angiogenesis in cancer progression has been established.Computed tomography(CT)perfusion(CTP)based on high temporal resolution CT images enables evaluation of hemodynamics of tissue in vivo by modeling tracer kinetics.CTP has been reported to characterize tumor angiogenesis,and to be a sensitive marker for predicting recurrence or survival in CRC.In this review,we will discuss the biomarker value of CTP in the management of CRC patients.

Computed tomography perfusion in liver and spleen for hepatitis B virus-related portal hypertension:A correlation study with hepatic venous pressure gradient

BACKGROUND Hepatic venous pressure gradient(HVPG)is the gold standard for diagnosis of portal hypertension(PH).However,its use can be limited because it is an invasive procedure.Therefore,it is necessary to explore a non-invasive method to assess PH.AIM To investigate the correlation of computed tomography(CT)perfusion of the liver with HVPG and Child-Pugh score in hepatitis B virus(HBV)-related PH.METHODS Twenty-eight patients(4 female,24 male)with gastroesophageal variceal bleeding induced by HBV-related PH were recruited in our study.All patients received CT perfusion of the liver before transjugular intrahepatic portosystemic stent-shunt(TIPS)therapy.Quantitative parameters of CT perfusion of the liver,including liver blood flow(LBF),liver blood volume(LBV),hepatic artery fraction,splenic blood flow and splenic blood volume were measured.HVPG was recorded during TIPS therapy.Correlation of liver perfusion with Child-Pugh score and HVPG were analyzed,and the receiver operating characteristic curve was analyzed.Based on HVPG(>12 mmHg vs≤12 mmHg),patients were divided into moderate and severe groups,and all parameters were compared.RESULTS Based on HVPG,18 patients were classified into the moderate group and 10 patients were classified into the severe group.The Child-Pugh score,HVPG,LBF and LBV were significantly higher in the moderate group compared to the severe group(all P<0.05).LBF and LBV were negatively associated with HVPG(r=-0.473,P<0.05 and r=-0.503,P<0.01,respectively),whereas splenic blood flow was positively associated with hepatic artery fraction(r=0.434,P<0.05).LBV was negatively correlated with Child-Pugh score.Child-Pugh score was not related to HVPG.Using a cutoff value of 17.85 mL/min/100 g for LBV,the sensitivity and specificity of HVPG≥12 mmHg for diagnosis were 80%and 89%,respectively.CONCLUSION LBV and LBF were negatively correlated with HVPG and Child-Pugh scores.CT perfusion imaging is a potential non-invasive quantitative predictor for PH in HBV-related liver cirrhosis.

Computed tomography perfusion study of hemodynamic changes and portal hyperperfusion in a rabbit model of small-for-size liver

BACKGROUND:Portal hyperperfusion in the small-for-size (SFS) liver can threaten survival of rabbits.Therefore,it is important to understand the hemodynamic changes in the SFS liver.METHODS:Twenty rabbits were divided into two groups:a control group and a modulation group.The control group underwent an extended hepatectomy.The modulation group underwent the same procedure plus splenectomy to reduce portal blood flow.CT perfusion examinations were performed on all rabbits before and after operation.Perfusion parameter values,especially portal vein perfusion (PVP),were analyzed.RESULTS:PVP in the modulation group was lower than in the control group after operation (P=0.002).In the control group,postoperative PVP increased by 193.7±55.1% compared with preoperative PVP.A weak correlation was found between the increased percentage of PVP and resected liver-to-body weight ratio (RLBWR) (r=0.465,P=0.033).In the modulation group,postoperative PVP increased by 101.4±32.5%.No correlation was found between the increased percentage of PVP and RLBWR (r=0.167,P=0.644).Correlations were found between PVP and serum alanine aminotransferase,aspartate aminotransferase,and total bilirubin after surgery (P<0.05).CONCLUSION:We successfully evaluated the characteristics of hemodynamic changes as well as the effects of splenectomy in the SFS liver in rabbits by the CT technique.

Computed tomography perfusion imaging evaluation of angiogenesis in patients with pancreatic adenocarcinoma

BACKGROUND Pancreatic adenocarcinoma is one of the most common malignant tumors of the digestive system.More than 80%of patients with pancreatic adenocarcinoma are not diagnosed until late stage and have distant or local metastases.AIM To investigate the value of computed tomography(CT)perfusion imaging in the evaluation of angiogenesis in pancreatic adenocarcinoma patients.METHODS This is a retrospective cohort study.Patients with pancreatic adenocarcinoma and volunteers without pancreatic diseases underwent CT perfusion imaging from December 2014 to August 2017 in Huashan Hospital,Fudan University Shanghai,China.RESULTS A total number of 35 pancreatic adenocarcinoma patients and 33 volunteers were enrolled.The relative blood flow(r BF),and relative blood volume(r BV)were significantly lower in patients with pancreatic adenocarcinoma than in the control group(P<0.05).Conversely,the relative permeability in patients with pancreatic adenocarcinoma was significantly higher than that in controls(P<0.05).In addition,r BF,r BV,and the vascular maturity index(VMI)were significantly lower in gradeⅢ-Ⅳpancreatic adenocarcinoma than in gradeⅠ-Ⅱpancreatic adenocarcinoma(P<0.05).Vascular endothelial growth factor(VEGF),CD105-MVD,CD34-MVD,and angiogenesis rate(AR)were significantly higher in gradeⅢ-Ⅳpancreatic adenocarcinoma than in gradeⅠ-Ⅱpancreatic adenocarcinoma(P<0.05).Significant correlations between r BF and VEGF,CD105-MVD,AR,and VMI(P<0.01)were observed.Moreover,the levels of r BV were statistically significantly correlated with those of VEGF,CD105-MVD,CD34-MVD,and VMI(P<0.01).CONCLUSION Perfusion CT imaging may be an appropriate approach for quantitative assessment of tumor angiogenesis in pancreatic adenocarcinoma.

Perihematomal Perfusion Typing and Spot Sign of Acute Intracerebral Hemorrhage with Multimode Computed Tomography: A Preliminary Study

Objective To explore the perihematomal perfusion typing and spot sign on computed tomography angiography(CTA) source images in order to assist in individualizing therapeutic decisions for patients with intracerebral hemorrhage by possibly forecasting perihematomal ischemia and hematoma enlargement. Methods We examined 58 patients with spontaneous intracerebral hemorrhage by computed tomography perfusion and CTA within 6 hours after symptom onset. Hematoma volumes were determined from non-contrast CT images and compared between first and second CT images. The perfusion of hematoma region and perihematoma region was evaluated for presence or absence of the perihematomal penumbra. Three kinds of perihematoma perfusion typing were defined according to the perfusion of hematoma region and perihematoma region. CTA source images was reviewed to make sure presence or absence of the spot sign. Results Finally, 53 patients(34 males, 19 females) were enrolled in our study according to exclusion criteria. Finally, 21 patients were classified into the normal group, 23 patients were classified into the mild group, and 9 patients were classified into the severe group. There were significant differences in hematoma size between the presence and absence of the perihematomal penumbra group(P<0.05). Thirteen(24.5%) patients presented with spot sign. Hematoma expansion occurred in 15(28.3%) patients on follow-up. In which 12 patients were with spot sign. Sensitivity, specificity, positive predictive value, and negative predictive value for expansion were 80.0%, 97.4%, 92.3%, and 92.5%, respectively. Conclusion In acute intracerebral hemorrhage patients, the perihematoma perfusion typing and CTA spot sign provide more radiological information that might assist in individualizing therapeutic decisions for patients by possibly forecasting perihematomal ischemia and hematoma enlargement.

Perfusion computed tomography in colorectal cancer:Protocols,clinical applications and emerging trends

Perfusion computed tomography (CT) has emerged as a novel functional imaging technique with gradually increasing importance in the management of colorectal cancer (CRC).By providing the functional tumor microvasculature,it also helps the assessment of therapeutic response of anti-angiogenic drugs as it may reflect tumor angiogenesis.Perfusion CT has been applied in clinical practice to delineate inflammatory or neoplastic lymph nodes irrespective of their size,identify micro-metastases and to predict metastases in advance of their development.It is of increasing significance for preoperative adjuvant therapies and avoidance of unnecessary interventions.Despite controversies regarding the techniques employed,its validity and reproducibility,it can be advantageous in the management of CRCs in which the prognosis is dependent on preoperative staging.With recent advances in the perfusion CT techniques,and incorporation to other modalities like positron emission tomography,perfusion CT will be a novel tool in the overall management of CRCs.This article aims at reviewing the existing clinical applications and recent advances of perfusion CT with a reference to future development in the management of CRCs.

Correlation of magnetic resonance signal characteristics and perfusion parameters assessed by volume perfusion computed tomography in hepatocellular carcinoma:Impact on lesion characterization

AIM: To find out if magnetic resonance(MR)-signal characteristics of hepatocellular carcinomas(HCC) correlate with perfusion parameters assessed by volume perfusion computed tomography(VPCT).METHODS: From October 2009 to January 2014, 26(mean age, 69.3 years) patients with 36 HCC lesions who underwent both VPCT and MR liver imaging were analysed. We compared signal intensity in the T1 wand T2w-images and wash-in/wash-out kinetics on postcontrast MR images with mean values of blood flow(BF, mL/100 mL per minute), blood volume(BV, mL/100 mL), k-trans(mL/100 mL per minute), arterial liver perfusion(mL/100 mL per minute), portal venous perfusion and hepatic perfusion index(HPI, %) obtained by VPCT. Signal intensity on magnetic resonance imaging(MRI) was classified hyper/iso/hypointense compared with surrounding liver parenchyma. RESULTS: Signal intensity on native T1w- and T2 wimages was hyper/iso/hypo in 4/16/16 and 21/14/1 lesions, respectively. Wash-in and wash-out contrast kinetics were found on MRI in 33 of 36 lesions(91.7%) and 25 of 36 lesions(69.4%), respectively. The latter was observed significantly more often in higher graded lesions(P < 0.005). HPI was 94.7% ± 6.5%. There was no significant relationship between lesion's MRsignal intensity, MR signal combinations, size and any of the VPCT-perfusion parameters. However HPI was constantly high in all HCC lesions.CONCLUSION: VPCT parameters add limited value to MR-lesion characterization. However in HCC lesions with atypical MR signal characteristics HPI can add a parameter to ensure HCC diagnosis.

Evaluation of the dual vascular supply patterns in ground-glass nodules with a dynamic volume computed tomography

BACKGROUND In recent years,the detection rate of ground-glass nodules(GGNs)has been improved dramatically due to the popularization of low-dose computed tomography(CT)screening with high-resolution CT technique.This presents challenges for the characterization and management of the GGNs,which depends on a thorough investigation and sufficient diagnostic knowledge of the GGNs.In most diagnostic studies of the GGNs,morphological manifestations are used to differentiate benignancy and malignancy.In contrast,few studies are dedicated to the assessment of the hemodynamics,i.e.,perfusion parameters of the GGNs.AIM To assess the dual vascular supply patterns of GGNs on different histopathology and opacities.METHODS Forty-seven GGNs from 47 patients were prospectively included and underwent the dynamic volume CT.Histopathologic diagnoses were obtained within two weeks after the CT examination.Blood flow from the bronchial artery[bronchial flow(BF)]and pulmonary artery[pulmonary flow(PF)]as well as the perfusion index(PI)=[PF/(PF+BF)]were obtained using first-pass dual-input CT perfusion analysis and compared respectively between different histopathology and lesion types(pure or mixed GGNs)and correlated with the attenuation values of the lesions using one-way ANOVA,student’s t test and Pearson correlation analysis.RESULTS Of the 47 GGNs(mean diameter,8.17 mm;range,5.3-12.7 mm),30(64%)were carcinoma,6(13%)were atypical adenomatous hyperplasia and 11(23%)were organizing pneumonia.All perfusion parameters(BF,PF and PI)demonstrated no significant difference among the three conditions(all P>0.05).The PFs were higher than the BFs in all the three conditions(all P<0.001).Of the 30 GGN carcinomas,14 showed mixed GGNs and 16 pure GGNs with a higher PI in the latter(P<0.01).Of the 17 benign GGNs,4 showed mixed GGNs and 13 pure GGNs with no significant difference of the PI between the GGN types(P=0.21).A negative correlation(r=-0.76,P<0.001)was demonstrated between the CT attenuation values and the PIs in the 30 GGN carcinomas.CONCLUSION The GGNs are perfused dominantly by the PF regardless of its histopathology while the weight of the BF in the GGN carcinomas increases gradually during the progress of its opacification.

Whole-brain CT Perfusion at Admission and During Delayed Time-window Detects the Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage

Objective To evaluate the utility of computed tomography perfusion(CTP)both at admission and during delayed cerebral ischemia time-window(DCITW)in the detection of delayed cerebral ischemia(DCI)and the change in CTP parameters from admission to DCITW following aneurysmal subarachnoid hemorrhage.Methods Eighty patients underwent CTP at admission and during DCITW.The mean and extreme values of all CTP parameters at admission and during DCITW were compared between the DCI group and non-DCI group,and comparisons were also made between admission and DCITW within each group.The qualitative color-coded perfusion maps were recorded.Finally,the relationship between CTP parameters and DCI was assessed by receiver operating characteristic(ROC)analyses.Results With the exception of cerebral blood volume(P=0.295,admission;P=0.682,DCITW),there were significant differences in the mean quantitative CTP parameters between DCI and non-DCI patients both at admission and during DCITW.In the DCI group,the extreme parameters were significantly different between admission and DCITW.The DCI group also showed a deteriorative trend in the qualitative color-coded perfusion maps.For the detection of DCI,mean transit time to the center of the impulse response function(Tmax)at admission and mean time to start(TTS)during DCITW had the largest area under curve(AUC),0.698 and 0.789,respectively.Conclusion Whole-brain CTP can predict the occurrence of DCI at admission and diagnose DCI during DCITW.The extreme quantitative parameters and qualitative color-coded perfusion maps can better reflect the perfusion changes of patients with DCI from admission to DCITW.

Cerebral pseudoinfarction due to venoarterial extracorporeal membrane oxygenation:A case report

BACKGROUND Neurological complications are common in the management of venoarterial extracorporeal membrane oxygenation(VA-ECMO),with most patients requiring sedation and intubation,limiting the assessment of neurological function.Therefore,we must rely on advanced neuroimaging techniques,such as computed tomography angiography(CTA)and computed tomography perfusion(CTP).Because ECMO changes the normal blood flow pattern,it may interfere with the contrast medium in some special cases,leading to artifacts and ultimately misleading clinical decisions.CASE SUMMARY A 61-year-old man presented to a local hospital with chest tightness and pain 1 d prior to presentation.The patient was treated with VA-ECMO after sudden cardiac and respiratory arrest at a local hospital.For further treatment,the patient was transferred to our hospital.The initial consciousness assessment was not clear,and routine CTP was performed to understand the intracranial changes,which suggested a large area of cerebral infarction on the right side;however,the cerebral oxygen was not consistent with the CTP results,and the reexamination of CTA still suggested a right cerebral infarction.To identify this difference,bedside transcranial Doppler was performed,and the blood flow on both sides was different.By reducing the ECMO flow,CTP reexamination showed that the results were normal and consistent with the clinical results.On day 3,the patient was alert and showed good limb movements.CONCLUSION In patients with peripheral VA-ECMO,cerebral perfusion confirmed by CTP and CTA may lead to false cerebral infarction.

Advanced imaging techniques in the therapeutic response of transarterial chemoembolization for hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is one of the major causes of morbidity and mortality in patients with chronic liver disease. Transarterial chemoembolization(TACE) can significantly improve the survival rate of patients with HCC and is the first treatment choice for patients who are not suitable for surgical resections. The evaluation of the response to TACE treatment affects not only the assessment of the therapy efficacy but also the development of the next step in the treatment plan. The use of imaging to examine changes in tumor volume to assess the response of solid tumors to treatment has been controversial. In recent years, the emergence of new imaging technology has made it possible to observe the response of tumors to treatment prior to any morphological changes. In this article, the advances in studies reporting the use of computed tomography perfusion imaging, diffusionweighted magnetic resonance imaging(MRI), intravoxel incoherent motion, diffusion kurtosis imaging, magnetic resonance spectroscopy, magnetic resonance perfusionweighted imaging, blood oxygen level-dependent MRI, positron emission tomography(PET)/computed tomography and PET/MRI to assess the TACE treatment response are reviewed.

New approaches for precise response evaluation in hepatocellular carcinoma

With the increasing clinical use of cytostatic and novel biologic targeted agents,conventional morphologic tumor burden assessments,including World Health Organization criteria and Response Evaluation Criteria in Solid Tumors,are confronting limitations because of their difficulties in distinguishing viable tumor from necrotic or fibrotic tissue.Therefore,the investigation for reliable quantitative biomarkers of therapeutic response such as metabolic imaging or functional imaging has been desired.In this review,we will discuss the conventional and new approaches to assess tumor burden.Since targeted therapy or locoregional therapies can induce biological changes much earlier than morphological changes,these functional tumor burden analyses are very promising.However,some of them have not gone thorough all steps for standardization and validation.Nevertheless,these new techniques and criteria will play an important role in the cancer management,and provide each patient more tailored therapy.

Radiofrequency ablation of locally advanced pancreatic adenocarcinoma:An overview

Radiofrequency ablation(RFA)of pancreatic neoplasms is restricted to locally advanced,non-resectable but nonmetastatic tumors.RFA of pancreatic tumors is nowadays an ultrasound-guided procedure performed during laparotomy in open surgery.Intraoperative ultrasound covers the mandatory role of staging,evaluation of feasibility,guidance and monitoring of the procedure.Different types of needle can be used.The first aim in the evaluation of RFA as a treatment for locally advanced pancreatic ductal adenocarcinoma,in order of evaluation but not of importance,is to determine the feasibility of the procedure.The second aim is to establish the effect of RFA on tumoral mass in terms of necrosis andcytoreduction.The most important aim,third in order of evaluation,is the potential improvement of quality of life and survival rate.Nowadays,only a few studies assess the feasibility of the procedure.The present paper is an overview of RFA for pancreatic adenocarcinoma.