CT Perfusion Examinations Research Articles

Carotid artery elongation (carotid dolichoarteriopathy): some features of the structure and hemodynamics

The purpose of the study. Multimodal study of the state of the brachiocephalic arteries, with assessment of blood flow in the extra- and intracranial portions of the carotid arteries and brain perfusion, as well as the structure of the brain in patients with different types of elongation of the carotid arteries (ECA).Material and methods. The data of examinations of 79 patients (45 men (57.0%, average age – 61.0 ± 10.1 years) and 34 women (43.0%, 65.3 ± 13.6 years), average age 62.8 ± 11.8 years) during the year after ischemic stroke in posterior circulation were analyzed. ECA was verified by multispiral computed tomographic angiography (msCTA) in 44 patients (55.7% of the total number of cases), the control group was selected by gender and age with “case-control” elements and consisted of 35 (44.3%) patients without a mustache. All underwent msCTA of the thoracic aorta and BCA and CT perfusion examination, magnetic resonance imaging of the brain, duplex scanning of BCA and transcranial duplex scanning, transthoracic echocardiography, transcranial Doppler monitoring with microembolodetection.Results. We have registered intergroup differences, which can be divided into structural and functional. The former include: higher aortic arch location in patients with DCA: ThII – 6.3% vs. 0%, ThIII – 43% vs. 0%; ThIV – 28.1% vs. 62.9%* and ThV 21.9% vs. 37.1% (p < 0.0005); lower values of cervical spine height (114.70 ± 11.03 mm, vs. 120.46 ± 9.75 mm, p = 0.022), greater absolute length of the ICA (on the right – 101.32 ± 14.59 mm vs. 85.06 ± 12.07 mm, p < 0.0005; on the left – 100.00 ± 14.03 mm vs. 84.66 ± 12.63 mm, p < 0.0005). The presence of ECA was associated (p < 0.05) with a higher frequency of vertebral artery elongation. The severity of small vessel disease during MRI in individuals with ECA was slightly higher (not at the trend level, p = 0.076). Functional differences consisted in the registration of lower (p = 0.019) values of the end diastolic velocity in M1 of the middle cerebral arteries. The values of some perfusion indices in the blood supply of elongation arteries were lower than in persons without ECA. There were no cases of registration of microembolic signals in the ECA patients examined by us.Conclusion. In the individuals with ECA we examined, a complex of anatomical and hemodynamic features was determined, which, both individually and collectively, cannot lead to a decrease in the level of blood flow or be a source of arterio-arterial embolism in the carotid system, regardless of the configuration of the ICA.

Computed tomography perfusion software pipelines to assess parameter maps and ischemic volumes: A comparative study.

This study was dedicated to investigating the agreement of the calculated results of two CT perfusion (CTP) postprocessing software packages, including parameter maps and ischemic volume, focusing on the infarct core volume (ICV) and penumbra volume (PV). A retrospective collection of 235 patients with acute ischemic stroke who underwent CTP examination were enrolled. All images had been analyzed with two software pipelines, RAPID CTP and AccuCTP, and the comparative analysis was based on ICV and PV results calculated by both software packages. The agreement of parameter maps was evaluated by root mean square error and Bland-Altman analysis. The ICV and PV agreement was evaluated by intraclass correlation coefficient (ICC) and Bland-Altman analysis. The accuracy of ICV and PV based on multiple thresholds was also analyzed. The ICV and PV of AccuCTP and RAPID CTP show excellent agreement. The relative differences of the parameter maps were all within 10% and the Bland-Altman analysis also showed a strong agreement. From ordinary least squares fitting results, both ICV and PV had a remarkably high goodness of fit (ICV, R2 = 0.975 [p<.001]; PV, R2 = 0.964 [p<.001]). For the ICC analysis, both had high ICC scores (ICV ICC 0.984, 95% CI [confidence interval] 0.973-0.989; PV ICC 0.955, 95% CI 0.947-0.964). Furthermore, multi-threshold analysis on the basis of ICV and PV also achieved reliable analytical accuracy. The image analysis results of AccuCTP are in excellent agreement with RAPID CTP and can be used as an alternative analysis tool to RAPID CTP software in stroke clinical practice.

Deep Learning-Based Image Registration in Dynamic Myocardial Perfusion CT Imaging.

Registration of dynamic CT image sequences is a crucial preprocessing step for clinical evaluation of multiple physiological determinants in the heart such as global and regional myocardial perfusion. In this work, we present a deformable deep learning-based image registration method for quantitative myocardial perfusion CT examinations, which in contrast to previous approaches, takes into account some unique challenges such as low image quality with less accurate anatomical landmarks, dynamic changes of contrast agent concentration in the heart chambers and tissue, and misalignment caused by cardiac stress, respiration, and patient motion. The introduced method uses a recursive cascade network with a ventricle segmentation module, and a novel loss function that accounts for local contrast changes over time. It was trained and validated on a dataset of n = 118 patients with known or suspected coronary artery disease and/or aortic valve insufficiency. Our results demonstrate that the proposed method is capable of registering dynamic cardiac perfusion sequences by reducing local tissue displacements of the left ventricle (LV), whereas contrast changes do not affect the registration and image quality, in particular the absolute CT (HU) values of the entire CT sequence. In addition, the deep learning-based approach presented reveals a short processing time of a few seconds compared to conventional image registration methods, demonstrating its application potential for quantitative CT myocardial perfusion measurements in daily clinical routine.

Reduction in Radiation Exposure of CT Perfusion by Optimized Imaging Timing Using Temporal Information of the Preceding CT Angiography of the Carotid Artery in the Stroke Protocol.

(1) Background: CT perfusion (CTP) is a fast, robust and widely available but dose-exposing imaging technique for infarct core and penumbra detection. Carotid CT angiography (CTA) can precede CTP in the stroke protocol. Temporal information of the bolus tracking series of CTA could allow for better timing and a decreased number of scans in CTP, resulting in less radiation exposure, if the shortening of CTP does not alter the calculated infarct core and penumbra or the resulting perfusion maps, which are essential for further treatment decisions. (2) Methods: 66 consecutive patients with ischemic stroke proven by follow-up imaging or endovascular intervention were included in this retrospective study approved by the local ethics committee. In each case, six simulated, stepwise shortened CTP examinations were compared with the original data regarding the perfusion maps, infarct core, penumbra and endovascular treatment decision. (3) Results: In simulated CTPs with 26, 28 and 30 scans, the infarct core, penumbra and PRR values were equivalent, and the resulting clinical decision was identical to the original CTP. (4) Conclusions: The temporal information of the bolus tracking series of the carotid CTA can allow for better timing and a lower radiation exposure by eliminating unnecessary scans in CTP.

CT perfusion-based delta-radiomics models to identify collateral vessel formation after revascularization in patients with moyamoya disease.

PurposeTo build CT perfusion (CTP)-based delta-radiomics models to identify collateral vessel formation after revascularization in patients with moyamoya disease (MMD).MethodsFifty-three MMD patients who underwent CTP and digital subtraction angiography (DSA) examination were retrospectively enrolled. Patients were divided into good and poor groups based on postoperative DSA. CTP parameters, such as mean transit time (MTT), time to drain (TTD), time to maximal plasma concentration (Tmax), and flow extraction product (FE), were obtained. CTP efficacy in evaluating surgical treatment were compared between the good and poor groups. The changes in the relative CTP parameters (ΔrMTT, ΔrTTD, ΔrTmax, and ΔrFE) were calculated to evaluate the differences between pre- and postoperative CTP values. CTP parameters were selected to build delta-radiomics models for identifying collateral vessel formation. The identification performance of machine learning classifiers was assessed using area under the receiver operating characteristic curve (AUC).ResultsOf the 53 patients, 36 (67.9%) and 17 (32.1%) were divided into the good and poor groups, respectively. The postoperative changes of ΔrMTT, ΔrTTD, ΔrTmax, and ΔrFE in the good group were significantly better than the poor group (p < 0.05). Among all CTP parameters in the perfusion improvement evaluation, the ΔrTTD had the largest AUC (0.873). Eleven features were selected from the TTD parameter to build the delta-radiomics model. The classifiers of the support vector machine and k-nearest neighbors showed good diagnostic performance with AUC values of 0.933 and 0.867, respectively.ConclusionThe TTD-based delta-radiomics model has the potential to identify collateral vessel formation after the operation.

Inhaled Nitric Oxide Treatment for Aneurysmal SAH Patients With Delayed Cerebral Ischemia.

BackgroundWe demonstrated experimentally that inhaled nitric oxide (iNO) dilates hypoperfused arterioles, increases tissue perfusion, and improves neurological outcome following subarachnoid hemorrhage (SAH) in mice. We performed a prospective pilot study to evaluate iNO in patients with delayed cerebral ischemia after SAH.MethodsSAH patients with delayed cerebral ischemia and hypoperfusion despite conservative treatment were included. iNO was administered at a maximum dose of 40 ppm. The response to iNO was considered positive if: cerebral artery diameter increased by 10% in digital subtraction angiography (DSA), or tissue oxygen partial pressure (PtiO2) increased by > 5 mmHg, or transcranial doppler (TCD) values decreased more than 30 cm/sec, or mean transit time (MTT) decreased below 6.5 secs in CT perfusion (CTP). Patient outcome was assessed at 6 months with the modified Rankin Scale (mRS).ResultsSeven patients were enrolled between February 2013 and September 2016. Median duration of iNO administration was 23 h. The primary endpoint was reached in all patients (five out of 17 DSA examinations, 19 out of 29 PtiO2 time points, nine out of 26 TCD examinations, three out of five CTP examinations). No adverse events necessitating the cessation of iNO were observed. At 6 months, three patients presented with a mRS score of 0, one patient each with an mRS score of 2 and 3, and two patients had died.ConclusionAdministration of iNO in SAH patients is safe. These results call for a larger prospective evaluation.

Pulmonary lesions: correlative study of dynamic triple-phase enhanced CT perfusion imaging with tumor angiogenesis and vascular endothelial growth factor expression

BackgroundTo investigate value of the quantitative perfusion parameters of dynamic triple-phase enhanced CT in differential diagnosis of pulmonary lesions, and explore the correlation between perfusion parameters of lung cancer with microvessel density (MVD) and vascular endothelial growth factor (VEGF).Methods73 consecutive patients with lung lesions who successfully underwent pre-operative CT perfusion examination with dynamic triple-phase enhanced CT and received a final diagnosis by postoperative pathology or a clinical follow-up. The cases were divided into malignant and benign groups according to the pathological results. CT perfusion parameters, such as Median, Mean, Standard deviation (Std), Q10, Q25, Q50, Q75, Q90 of pulmonary artery perfusion (PAP), bronchial artery perfusion (BAP), perfusion index (PI) and arterial enhancement fraction (AEF) were obtained by performing computed tomography perfusion imaging (CTPI). Computed tomography perfusion (CTP) parameters were compared between malignant and benign lesions. The receiver operating characteristic (ROC) curve was used to assess the diagnostic efficiency of CTP parameters in diagnosing malignant lesions. The correlations between CTP parameters with MVD and VEGF were analysed in 36 lung cancer patients who had extra sections be used for immunohistochemistry staining of CD34 and VEGF.ResultsBAP (Mean, Std, Q90) and PI Std of benign lesions were higher than malignant lesions (p < 0.05), and PAP (Q10, Q25), PI (Median, Mean, Q10, Q25, Q50) of malignant lesions were higher than the benign (p < 0.05). The area under the ROC curve of PI Mean, PI Q10 and PI Std was 0.722 (95% CI = [0.595–0.845]), 0.728 (95% CI = [0.612–0.844]) and 0.717 (95% CI = [0.598–0.835]) respectively. Partial perfusion parameters of BAP and AEF Q10 were positively correlated with MVD (p value range is < 0.001–0.037, ρ value range is 0.483–0.683), and partial perfusion parameters of PI were negatively correlated with MVD (p value range is 0.001–0.041,ρvalue range is − 0.523–− 0.343). Partial perfusion parameters of BAP and AEF Q10 were positively correlated with VEGF (p value range is 0.001–0.016, ρvalue range is 0.398–0.570), meanwhile some perfusion parameters of PAP and PI were negatively correlated with VEGF (p value range is 0.001–0.040, ρ value range is − 0.657–0.343).ConclusionsQuantitative parameters of dynamic triple-phase enhanced CT can provide diagnostic basis for the differentiation of lung lesions, and there were connection with tumor angiogenesis and vascular endothelial growth factor expression.

Cerebral vasospasm and hypoperfusion after traumatic brain injury: Combined CT angiography and CT perfusion imaging study.

Background: Timely identification of the cerebral perfusion abnormalities after traumatic brain injury (TBI) is highly important. The objective of this study was the evaluation of the post traumatic vasospasm and cerebral hypoperfusion with the serial combined CT angiography (CTA) and CT perfusion (CTP) imaging examinations.Methods: The case series comprised 25 adult patients with closed TBI accompanied by various types of intracranial hematoma. Emergency surgery was done in 15 cases (60%). Combined CTA and CTP were performed on days 0 (D0) and 7 ± 1 (D7) after trauma.Results: CTA on D0 did not demonstrate vasospasm in any case but revealed it on D7 in 9 patients (36%). In the multivariate analysis, only the presence of subarachnoid hemorrhage (SAH) on D7 had confirmed a significant association with the development of vasospasm (P = 0.0201). Cerebral hypoperfusion at least in one evaluated brain region was noted on D0 and D7 in 76% and 60% of patients, respectively, and showed highly variable spatial distribution and temporal development. Treatment results were not associated with the presence of vasospasm (P = 0.7337) or the number of brain regions affected by hypoperfusion on D0 (P = 0.2285), but the number of brain regions affected by hypoperfusion on D7 was significantly greater in cases of unfavorable outcome (P = 0.0187).Conclusion: Vasospasm is merely related to SAH sustained at the subacute stage of TBI, but its spatial and temporary interrelationships with the post traumatic cerebral hypoperfusion are complex. Serial combined CTA and CTP examinations may facilitate monitoring of perfusion abnormalities and treatment guidance.

Low-dose CT perfusion with combined use of CTP and CTP-derived coronary CT angiography at 70kVp: validation with invasive fractional flow reserve.

To investigate the diagnostic performance of 70-kVp stress dynamic myocardial CT perfusion (CTP) as a low-dose, one-stop cardiac CT examination in clinical application. Consecutive symptomatic patients were prospectively recruited and scanned with stress dynamic myocardial CTP. The CTP phase with the best enhancement of the coronary arteries was selected and extracted as the CTP-derived single-phase coronary CT angiography (SP-CTA). The diagnostic performance of CTP and CTP+SP-CTA for functionally significant CAD was assessed. Invasive coronary angiography and fractional flow reserve were used as the reference standard for the myocardial ischemia evaluation. In total, 71 patients (43 men and 28 women; 63.6 ± 8.8years old) underwent the stress dynamic myocardial CTP; 63 vessels (36.2%) from 42 of the patients (59.2%) were identified as causing ischemia. On a per-vessel basis, the sensitivity, specificity, PPV, NPV, and diagnostic accuracy for CTP and CTP+SP-CTA were 77.8%, 93.7%, 87.5%, 88.1%, and 87.9% and 84.1%, 93.7%, 88.3%, 91.2%, and 90.2%, respectively. The area under the curve (AUC) of CTP+SP-CTA (AUC = 0.963; 95%CI, 0.938-0.989) was significantly superior to that of CTP (AUC = 0.922; 95%CI, 0.880-0.964) and that of SP-CTA (AUC = 0.833; 95%CI, 0.765-0.900) alone (all p < 0.01). The mean radiation dose of the CTP examination was 3.8 ± 1.4mSv. CTP-derived SP-CTA improved the diagnostic value of CTP. With a promising performance of myocardial ischemia detection and low radiation dose, the innovative low-dose, one-stop CTP examination is clinically feasible for patients who need to receive a myocardial perfusion assessment. • Myocardial CTP performed well in the evaluation of hemodynamically significant CAD. • CTP-derived single-phase CCTA improved the diagnostic value of CTP. • The combined use of low-dose CTP and CTP-derived CCTA at 70kVp is clinically feasible for CAD patients who need to receive a myocardial perfusion assessment.

Clinical value of brain CT perfusion imaging combined with head and neck CTA in the diagnosis of acute ischemic stroke

Objective To investigate the clinical value of whole brain CT perfusion imaging combined with head and neck CTA in the diagnosis of acute ischemic stroke. Methods From November 2016 to November 2018, the clinical data and medical imaging data of 220 patients diagnosed as acute ischemic stroke in the Department of Neurology, Dajiangdong Hospital were selected.All patients underwent CT scan followed by a CT perfusion scan and a routine cranial CTA.The radiation dose was recorded.The ischemic lesions and their stenosis were analyzed by CTA.CT perfusion imaging was used to analyze regional cerebral blood flow imaging (rCBF), tissue perfusion (rCBV) and mean passage time (MTT) in all patients..And the test performance of the two inspection methods was compared. Results CTA was used to analyze vascular stenosis.The stenotic vessels were mainly distributed in the M1~M3 segment (3 cases of them were completely obstructed, 11 cases were obstructed ≥50%, 19 cases were 30% ≤ stenosis<50%), and A1~A3 segments (4 cases of them were obstructed, 7 cases were 30% ≤ stenosis<50%), and basilar artery (2 cases of them occlusion, 6 cases of ≥ 50%, 11 cases of 30% ≤ stenosis<50%). CT perfusion examination was performed in the whole brain.The rCBF of the control area was higher than that of the ischemic penumbra and higher than the infarct area.The rCBF values were (50.31±11.21)100 g/min, (34.45±22.17)100 g/min and (6.87±3.52)100 g/min, respectively, the difference was statistically significant (t=17.81, 19.14, all P<0.05). The region rCBV of the control area was higher than that of the ischemic penumbra and the infarct region, and the rCBV values were (3.35±1.01)mL/100g, (2.87±0.55)mL/100g and (6.87±0.51)mL/100g, respectively, the differences are statistically significant (t=6.47, 9.19, all P<0.05). The MTT in the control area was lower than that in the ischemic penumbra and the infarct area, and the MTT values were (4.52±1.21)s, (7.88±1.01)s and (11.81±1.18)s, respectively, the differences are statistically significant(t=10.50, 13.54, all P<0.05). The two methods were compared for consistency, and the kappa value was greater than 0.75, showed a high degree of consistency. Conclusion CT perfusion imaging and CTA have little difference in the diagnostic efficacy for patients with acute ischemic cerebral infarction, and can accurately diagnose the disease.CT perfusion imaging can determine the location of the ischemic penumbra, and CTA can be analyzed based on the stage of the diseased vessel.Both two methods can play different guiding role for individualized treatment. Key words: Tomography, spiral computed; Perfusion imaging; Angiography; Cerebrovascular disorders; Retrospective study

Abstract 3: Quantitative Collateral Vessel Density Associated With the Prognosis of Mechanical Thrombectomy on Intracranial Large Vessel Occlusion: An Initial Study Based on CT Perfusion Imaging

Objective: This study on acute ischemic stroke caused by large vessel occlusion (LAO) aims to explore the correlation between collateral circulation and the prognosis of mechanical thrombectomy (MT), and further evaluate the high-risk factors of the prognosis of MT by quantitatively measuring the collateral vessel density (CVD) using F-STROKE software. Methods: This study was retrospectively analyzed on 92 patients with acute ischemic stroke caused by LAO from January 2018 to October 2018. All patients underwent MT and CT perfusion (CTP) examination before operation. mRS evaluation was performed after 90 days. The patients were divided into two groups according to 90d-mRS (0-2 points: good prognosis; 3-6 points: poor prognosis) F-stroke software was used for CTP image analysis to quantitatively obtain core infarct volume, ischemic penumbra volume, mismatch ratio and CVD (CVD = the vessel volume of the hypoperfusion region / the volume of the hypoperfusion region). Multivariate logistic regression model was used for statistical analysis. Results: A total of 87 patients with LAO were included in this study, including 54 patients with good prognosis. The univariate analysis showed that core infarction volume (P=0.017), mismatch ratio (P=0.040), CVD (P=0.003) and symptom improvement (P&lt;0.001) were associated with the prognosis after MT. As multivariate Logistic regression analysis shown, CVD (P=0.008; OR=13.296; 95%CI, 1.948-90.736) and symptom improvement (P=0.003; OR=13.824; 95%CI, 2.476-77.196) were two independent high-risk factors of the prognosis of MT. According to ROC (figure 1), the AUC value of CVD and symptom improvement were 0.839 and 0.790, respectively. When combining both of the two features to predict the prognosis of thrombolysis, the AUC value has been improved to 0.887. Conclusion: For patients with LAO who underwent MT, CVD was an independent quantitative predictor to the prognosis after MT surgery.

Stress dynamic myocardial CT perfusion for symptomatic patients with intermediate- or high-risk of coronary artery disease: Optimization and incremental improvement between the absolute and relative myocardial blood flow analysis

BackgroundThe optimization of myocardial CT perfusion (CTP) assessment remains inconsistent and uncertain. Our aim was to explore the superior analysis selection and incremental improvement of myocardial blood flow (MBF) assessment on CTP in diagnosing hemodynamically significant coronary artery disease (CAD). MethodsSixty patients (43 men and 17 women; 61.38 ± 8.01 years) were prospectively recruited and underwent stress dynamic myocardial CTP examinations. Absolute and relative MBF was used for ischemia evaluation with the invasive coronary angiography and fractional flow reserve were used as the reference standard. Areas under the receiver operating characteristic curves (AUCs) and cutoff values were calculated and compared. ResultsThere were 151 vessels in 60 patients finally enrolled for analysis. The sensitivity, specificity, PPV, NPV and diagnostic accuracy for the absolute MBF value and relative MBF ratio were 82.76%, 98.92%, 97.96%, 90.20%, and 92.72% and 74.14%, 93.56%, 87.76%, 85.29%, and 86.09%, respectively. The absolute MBF value was superior than the relative MBF ratio in detecting ischemia (AUC, 0.955 [95%CI: 0.919–0.990] vs.0.906 [95%CI:0.857–0.954])(P = 0.02). For territories with both sensitivity and specificity ≤90%, the diagnostic accuracy increased from 79.1% to 88.4% when the specific data were assessed using the absolute MBF value instead of the relative MBF ratio. ConclusionsThe absolute MBF value from the endocardial myocardium on stress dynamic myocardial CTP showed superior diagnostic performance compared to the relative MBF ratio for the detection of myocardial ischemia in intermediate-to-high risk patients. The absolute MBF value provides an incremental benefit toward diagnostic performance for the relative MBF ratio evaluation.

Diaschisis revisited: quantitative evaluation of thalamic hypoperfusion in anterior circulation stroke

PurposeIpsilateral thalamic diaschisis (ITD) refers to the phenomenon of thalamic hypoperfusion or hypometabolism due to a distant cerebral injury. To further investigate the characteristics and spectrum of ITD, we analyzed quantitative measurements of thalamic hypoperfusion in acute anterior circulation stroke. MethodsWe selected consecutive patients with large-vessel occlusion (LVO) anterior circulation stroke and available CT perfusion (CTP) examination on admission who underwent endovascular thrombectomy. Thalamic perfusion parameters on CTP were tested between ipsi- and contralesional thalamus and ischemic territory. Values were compared with thresholds from CTP analysis software. Associations of thalamic perfusion parameters with acute imaging and clinical data were determined in uni- and multivariate logistic regression analyses. ResultsNinety-nine patients were included. All perfusion parameters indicated significant non-ischemic hypoperfusion of the thalamus, not reaching the levels of ischemia in the middle cerebral artery territory due to LVO (all p < 0.002). Multiple perfusion parameters exhibited significant association with ischemic lesion extent (relative cerebral blood flow [CBF]: β = − 0.23, p = 0.022; Δtime to drain: β = 0.33, p < 0.001; ΔTmax: β = − 0.36, p < 0.001) and involvement of the Lentiform Nucleus (Δmean transit time: β = 0.64, p = 0.04; Δtime to drain: β = 0.81, p = 0.01; ΔTmax: β = − 0.82, p = 0.01). Symptom severity on admission exhibited minor significant association with reduction of thalamic CBF in uncorrected analysis (Odds ratio: 0.05, p = 0.049), but short- and long-term outcomes were unaffected by perfusion status. ITD reached guideline-based software-threshold levels in only one patient. ConclusionsITD in acute stroke is a non-binary phenomenon affected by lesion extent and involvement of the lentiform nucleus. We found uncorrected association of ITD with early clinical presentation, but no association with short- or long-term outcome was evident. Relevant misclassification of ITD by guideline-based CTP software was not indicated, which needs further dedicated testing.

Diagnostic accuracy of perfusion-CT using Peak Enhancement Intensity (PEI) in detecting high grade pancreatic ductal adenocarcinoma keeping histopathology as gold standard.

Pancreatic ductal carcinoma is the most common primary malignancy of the pancreas and is associated with a very poor prognosis, being worldwide one of the leading cause of cancer related death. The pre-operative correct identification of this group of patients is very important to minimize unnecessary resections but remains difficult owing to the post-operative assessment of some factors such as tumor resection margins and grading. Perfusion CT (P-CT) is a new imaging technique able to provide qualitative and quantitative information on perfusion parameters of tissues, which have been demonstrated to be correlated with histological markers of angiogenesis. Objectives: To estimate the diagnostic accuracy of CT perfusion using PEI in detecting high grade pancreatic ductal adenocarcinoma keeping histopathology as gold standard. Study Design: Cross sectional study. Setting: Radiology department of Allied Hospital Faisalabad. Period: 6 months after approval from June, 2016 to Nov, 2016. Material and Methods: Permission for research was sought from hospital ethical committee. Patients were collected from OPD &amp; indoor of Radiology and surgical department of Allied Hospital Faisalabad. Confounding variables were controlled by restriction (by excluding the subjects with history of metastatic disease or chemotherapy). CT-Perfusion examination was performed with the patient in supine position on a 128 slice Optima Multi detector CT scanner. Image guided (CT guided) biopsy was done on all patients and specimen was sent to the hospital pathology lab and histopathology was done by senior pathologist, who kept blinded to perfusion-CT analysis. Results: In this study, out of 100 cases, the diagnostic accuracy of CT perfusion using PEI in detecting high grade pancreatic ductal adenocarcinoma keeping histopathology as gold standard was recorded as 90.59%, 91.49%, 92.31%, 89.58% and 91% for sensitivity, specificity, positive predictive value, negative predictive value and accuracy rate. Conclusion: We concluded that diagnostic accuracy of CT perfusion using PEI is higher in detection of high grade pancreatic ductal adenocarcinoma keeping histopathology as gold standard.

Et si l’imagerie neurologique nous était expliquée ?

Brain CT Perfusion (CTP) is an X-ray imaging technique for the assessment of brain tissue perfusion, which can be used in several different entities. The aim of this study is the evaluation of the radiation dose to patients during a comprehensive brain CT prescription protocol (CPP) consisting of an unenhanced brain CT, a brain CT angiography and a CTP scan.Eighteen patients were studied using an 80-slice CT system, with an iterative reconstruction algorithm. The volume Computed Tomography Dose Index (CTDIvol) and dose length product (DLP) were recorded from the dose report of the system. The calculation of effective dose (ED) was accomplished using the DLP values.For the CTP examinations, the CTDIvol ranged from 116.0 to 134.8 mGy, with the mean value 119.5 mGy. The DLP ranged from 463.9 to 539.2 mGy·cm, with the mean value 478 mGy·cm. For the CPP, the total ED ranged from 3.31 to 5.07 mSv, with the mean value 4.37 mSv.These values are lower than the values reported in corresponding studies, including studies utilizing CT systems with more slices.

Clinical application value of brain CT perfusion imaging in the treatment of acute ischemic stroke thrombolytic therapy.

Clinical application value of CT perfusion (CTP) imaging in the treatment of acute ischemic stroke (AIS) thrombolytic therapy was investigated. Retrospective analysis of 185 suspected AIS patients in Liaocheng Brain Hospital from April 2012 to December 2017 were involved. We observed the non-contrast CT (NCCT) and CTP in the diagnosis of AIS patients, and recorded as well as compared CTP parameters of AIS patients. The National Institute of Health Stroke Scale (NIHSS) rating was conducted, and the correlation between the prognosis of NIHSS scores and CTP parameters was investigated. A total of 177 patients were diagnosed with AIS. The sensitivity levels of CTP examination for diagnosis of AIS patients was significantly higher than that of the NCCT examination (P<0.050). The diagnostic compliance rates of CTP examination was significantly higher than that of the NCCT examination (P<0.050). The cerebral blood volume (CBV) in the abnormal perfusion area was significantly lower than that in the mirror side zone (t=21.160, P<0.001). The prognostic NIHSS score was negatively correlated with CBV in patients with thrombolytic therapy (r=−0.912, P<0.001). The cerebral blood flow (CBF) in the abnormal perfusion zone was significantly lower than that in the mirror side zone (t=19.170, P<0.001). The prognosis of patients with thrombolytic therapy was negatively correlated with CBF (r=−0.915, P<0.001). The mean transit time (MTT) in the abnormal perfusion zone was higher than that in the mirror side zone (t=13.480, P<0.001). NIHSS scores were obtained 3 months after thrombolytic therapy and found that the prognostic NIHSS scores were positively correlated with MTT (r=0.887, P<0.001). The results indicated that brain CTP has a high diagnostic value for intravenous thrombolytic therapy in AIS and there was a significant correlation between the prognosis scores of patients. Thus, it is worthy of being promoted in the clinical diagnosis and treatment of AIS patients.

Significance of CT perfusion examination of cerebral blood flow for assessing the risk of brain ischemia in patients with intracranial arterial aneurysm ruptures

The study purpose was to evaluate the significance of cerebral blood flow indicators obtained by CT perfusion for prediction of delayed cerebral ischemia and postoperative ischemic complications to optimize treatment of patients with ruptures of intracranial arterial aneurysms. The study included 70 patients who underwent aneurysm clipping and 42 non-operated patients. The inclusion criteria were as follows: WFNS grade I-III condition, vasospasm according to transcranial Doppler sonography, and availability of CT scans, including CT perfusion data. The vasospasm severity and perfusion indicators _(rCBV and MTT) were evaluated. The severity of subarachnoid and ventricular hemorrhage was evaluated according to the A. Hijdra method. The final results were evaluated using a clinical-statistical method, including ROC analysis. An analysis of the obtained data revealed that the risk of delayed cerebral ischemia and postoperative ischemia increases significantly if the baseline hemispheric CBF value is below a threshold of 40 ml/100 g/min, and the baseline MMT indicator is above a threshold of 5 s. There was asymmetry of these CT perfusion indicators due to a larger deviation from the threshold values in the homolateral hemisphere compared to the opposite side. The ROC analysis results demonstrated diagnostic sensitivity and diagnostic specificity of the CT perfusion technique. The CT perfusion data together with the SAH severity and localization indicators may be used as predictors for the cerebral ischemia outcome in choosing the optimal timing of aneurysm clipping during the acute SAH period in patients in a WFNS grade I-III condition and with signs of mild or moderate vasospasm.

Volumetric analysis of intracranial vessels: a novel tool for evaluation of cerebral vasospasm.

Together with other diagnostic modalities, computed tomography angiography (CTA) is commonly used to indicate endovascular vasospasm treatment after subarachnoid hemorrhage (SAH), despite the fact that objective, user-independent parameters for evaluation of CTA are lacking. This exploratory study was designed to investigate whether quantification of vasospasm by automated volumetric analysis of the middle cerebral artery M1 segment from CTA data could be used as an objective parameter to indicate endovascular vasospasm treatment. We retrospectively identified SAH patients who underwent transcranial Doppler sonography (TCD), CTA, and CT perfusion (CTP), with or without subsequent endovascular treatment. We determined vessel volume/vessel length of the M1 segments from CTA data and used receiver operating characteristic curve analysis to determine the optimal threshold of vessel volume to predict vasospasm requiring endovascular treatment. In addition, blinded investigators independently analyzed TCD, CTA, and CTP data. Of 45 CTA examinations with corresponding CTP and TCD examinations (24 SAH patients), nine indicated the need for endovascular vasospasm treatment during examination. In our patients, vessel volume < 5.8µL/mm was moderately sensitive but fairly specific to detect vasospasm requiring endovascular treatment (sensitivity, 67%; specificity, 78%; negative predictive value (NPV), 89%; positive predictive value (PPV), 46%). For CTA, CTP, and TCD, we found NPVs of 96%, 92%, and 89%, PPVs of 40%, 35%, and 35%, sensitivities of 89%, 78%, and 67%, and specificities of 67%, 64%, and 69%, respectively. Vessel volumes could provide a new objective parameter for the interpretation of CTA data and could thereby improve multimodal assessment of vasospasm in SAH patients.

Patient dose in brain perfusion imaging using an 80-slice CT system

Background and purposeBrain CT Perfusion (CTP) is an X-ray imaging technique for the assessment of brain tissue perfusion, which can be used in several different entities. The aim of this study is the evaluation of the radiation dose to patients during a comprehensive brain CT prescription protocol (CPP) consisting of an unenhanced brain CT, a brain CT angiography and a CTP scan. Materials and methodsEighteen patients were studied using an 80-slice CT system, with an iterative reconstruction algorithm. The volume Computed Tomography Dose Index (CTDIvol) and dose length product (DLP) were recorded from the dose report of the system. The calculation of effective dose (ED) was accomplished using the DLP values. ResultsFor the CTP examinations, the CTDIvol ranged from 116.0 to 134.8mGy, with the mean value 119.5mGy. The DLP ranged from 463.9 to 539.2mGy·cm, with the mean value 478mGy·cm. For the CPP, the total ED ranged from 3.31 to 5.07mSv, with the mean value 4.37mSv. ConclusionsThese values are lower than the values reported in corresponding studies, including studies utilizing CT systems with more slices.

Single-phase coronary artery CT angiography extracted from stress dynamic myocardial CT perfusion on third-generation dual-source CT: Validation by coronary angiography

BackgroundCT advances allow coronary arterial tree to be entirely covered during one CTP scan. Our aim was to investigate the potential value of single-phase coronary CT angiography (SP-CCTA) extracted from stress dynamic myocardial CT perfusion (CTP) for coronary artery stenosis assessment. MethodsConsecutive symptomatic patients were prospectively recruited and scanned with an ATP-stress dynamic myocardial CTP and routine CCTA protocol using third-generation DSCT. Noise reduction was applied to optimize image quality (IQ), the CTP phase with the best enhancement of the coronary arteries was selected as the SP-CCTA. IQ was assessed qualitatively. Using coronary angiography (CAG) as the reference standard, the diagnostic performance for stenosis detection was compared for SP-CCTA and routine CCTA. Results56 patients underwent the CTP and CCTA examination, among which 39 patients underwent CAG. The qualitative IQ scores of SP-CCTA were similar to that of routine CCTA (p > 0.05). On a per-segment basis, the sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy and area under the receiver-operating-characteristic curve results of SP-CCTA and routine CCTA for diagnosis of stenosis ≥50% exhibited no significant difference (SP-CCTA: 78.1%, 94.9%, 77.4%, 95.1%, 91.6% and 0.935 vs. routine CCTA: 74.7%, 95.3%, 78.0%, 95.3%, 91.6% and 0.937; all p > 0.05). The mean effective radiation dose of CTP and routine CCTA plus CTP were 3.92 ± 1.72 mSv and 5.98 ± 2.01 mSv (p < 0.05), respectively. ConclusionsThe IQ and diagnostic value of SP-CCTA was equivalent to routine CCTA on third-generation DSCT. SP-CCTA images from CTP may potentially replace a separate routine CCTA, allowing the possibility of “one-stop” cardiac examination for high-risk CAD patients who need myocardial ischemia assessment.