CT Perfusion Scans Research Articles

Value of dual-input perfusion of 320 row CT on the efficacy evaluation of small cell lung cancer

Objective To discuss the value of dual-input perfusion of 320 row CT on the efficacy evaluation of small cell lung cancer (SCLC). Methods A total of 18 patients with SCLC confirmed by pathology who received cisplatin plus etoposide chemotherapy between June 2016 and June 2018 in the 8th Medical Center of Chinese PLA General Hospital were collected. All patients received 320 row CT perfusion scan at 3 time points before chemotherapy, after 2 cycles and 4 cycles of chemotherapy. Tumor size, perfusion pseudo color map and bronchial arterial blood flow (BF), pulmonary flow (PF) and perfusion index (PI) were obtained. The efficacy and adverse reactions were evaluated. The single factor analysis was used to make the group comparison. Pearson test was used to make correlation analysis. Results Two patients after 2 cycles of chemotherapy had complete remission (CR), another 2 patients after 4 cycles of chemotherapy had CR, and 3 patients of the above 4 cases with CR had abundant BF; after 4 cycles of chemotherapy, 7 cases had partial remission (PR), 6 cases had stable disease (SD), 1 patient had progression of disease (PD). Dual-input perfusion of 320 row CT showed that 10 cases had the tumor area 15 cm2 before the treatment. There was a negative correlation between PI and the tumor area (r=-0.694, P = 0.026) on patients with the tumor area 15 cm2 (P > 0.05). One case had Ⅳ degree of bone marrow suppression, and obvious adverse reactions were not seen in the rest of the patients. Conclusion Dual-input perfusion of 320 row CT based on the simple imaging can make an accurate quantitative judgement of the effect of SCLC according to perfusion parameter, which provides a new basis for curative effect evaluation on SCLC. Key words: Small cell lung carcinoma; Pulmonary perfusion imaging; Dual-input perfusion CT; Treatment outcome

Topographic correlation of infarct area on CT perfusion with functional outcome in acute ischemic stroke.

The role of CT perfusion (CTP) in the management of patients with acute ischemic stroke (AIS) remains a matter of debate. The primary aim of this study was to evaluate the correlation between the areas of infarction and penumbra on CTP scans and functional outcome in patients with AIS. This was a retrospective review of 100 consecutively treated patients with acute anterior circulation ischemic stroke who underwent CT angiography (CTA) and CTP at admission between February 2011 and October 2014. On CTP, the volume of ischemic core and penumbra was measured using the Alberta Stroke Program Early CT Score (ASPECTS). CTA findings were also noted, including the site of occlusion and regional leptomeningeal collateral (rLMC) score. Functional outcome was defined by modified Rankin Scale (mRS) score obtained at discharge. Associations of CTP and CTA parameters with mRS scores at discharge were assessed using multivariable proportional odds logistic regression models. The median age was 67 years (range 19-95 years), and the median NIH Stroke Scale score was 16 (range 2-35). In a multivariable analysis adjusting for potential confounding variables, having an infarct on CTP scans in the following regions was associated with a worse mRS score at discharge: insula ribbon (p = 0.043), perisylvian fissure (p < 0.001), motor strip (p = 0.007), M2 (p < 0.001), and M5 (p = 0.023). A worse mRS score at discharge was more common in patients with a greater volume of infarct core (p = 0.024) and less common in patients with a greater rLMC score (p = 0.004). The results of this study provide evidence that several CTP parameters are independent predictors of functional outcome in patients with AIS and have potential to identify those patients most likely to benefit from reperfusion therapy in the treatment of AIS.

Abstract TP460: Recognizing Large Vessel Occlusions Earlier in the Stroke Alert Process

Background: As an Agency for Healthcare Administration (AHCA) Comprehensive Stroke Center we were looking for ways to decrease our door to groin puncture time for patients that had Large Vessel Occlusions (LVO) requiring mechanical thrombectomy. We found patients were often making two trips to the CT scanner. First for their plain brain CT to rule out blood and then for a CT Angiogram and CT Perfusion scan if it appeared the patient was having a Large Vessel Occlusion (LVO). Our mean groin puncture time for mechanical thrombectomy was 116 minutes in 2015. Purpose: To recognize the signs and symptoms of a LVO and save time by completing the plain brain CT scan, the CT Angiogram, and the CT Perfusion scan on the same trip to the CT department. Method: Our vascular neurologist reviewed the signs and symptoms of Large Vessel Occlusions utilizing V.A.N. (vision, aphasia, neglect) criteria with the Emergency Room Physicians, the Emergency Room Nurses, the Clinical Resource Nurses as well as all Emergency Medical Services (EMS) personnel. Lectures were given as well as hands on demonstrations. Telemedicine was asked to see the patient upon arrival in the ambulance bay to observe for LVO as well. Mock codes were run on both campuses with success. Results: Initially all stroke alerts were getting CT Angiograms and CT Perfusions completed regardless of whether they were VAN positive. However, after we reviewed all the false positives the number of patients actually getting these scans decreased to those that truly needed them. EMS now feels comfortable and competent calling LVO’s in the field. As do the Emergency Room physicians. As a result of these patients getting their required scans in one trip to the CT department, our door to groin puncture time has decreased from 116 minutes to a mean of 56 minutes. Conclusion: In conclusion, we found that adopting the utilization of VAN criteria to recognize LVO’s has decreased the mean door to groin puncture time for mechanical thrombectomy allowing for sooner return of circulation to the brain and improving patient outcomes.

Abstract TP80: Deep Learning Based Prediction of Tissue Status From Native CT Perfusion Images

Introduction: CT Perfusion (CTP) imaging allows estimations of the ischemic core and penumbra. We hypothesize that a deep learning approach improves upon classic deconvolution analysis. Method: We trained a deep neural network to predict the final infarct volume based on the native CTP images, time to reperfusion and reperfusion status in a derivation cohort (MR CLEAN study). Given a CTP scan, prediction of the final infarct with simulated treatment parameters (instant reperfusion or no reperfusion at all), allows estimation of core and perfusion lesion. The model was validated in a five-fold cross-validation on the derivation cohort and, without retraining, on an external dataset (CRISP study). We calculated the mean absolute difference (MAD) between the volumes of the predicted core/perfusion lesion and true final infarct in reperfusers and non-reperfusers (based on 24h MRA and mTICI at the end of the procedure: 0 vs 2B-3) and compared these to the volume estimations of CTP processing by IschemaView RAPID. We assumed the measured final infarct to correspond to the core at baseline in reperfused patients and to the perfusion lesion in non-reperfused patients. Results: In the derivation cohort the deep learning prediction improved core prediction in reperfusers (MAD of 34 ml vs 66 ml, p&lt;0.001) and provided equivalent results in non-reperfusers for perfusion lesion prediction (both MAD of 35ml, p=0.5). Validation on the CRISP dataset showed improved core prediction (MAD of 32 ml vs 37 ml, p&lt;0.001) and was inconclusive for non-reperfusers (n=3). Conclusion: We developed and validated a deep learning based method which improved volume estimations compared to classic CTP processing.

Abstract TP92: When Less is More: Do We Need Advanced Perfusion Neuroimaging Prior to Mechanical Thrombectomy?

Objective: To assess whether the choice of pretreatment neuroimaging has an impact on clinical outcomes following mechanical thrombectomy (MT). Background: Most MT trials required advanced neuroimaging including either CT or MR based perfusion studies for patient selection prior to randomization. However, in practice, centers may offer MT based on favorable findings (ASPECT score &gt; 6) on non-contrast head CT (HCT) ± CT angiogram (CTA). We compared outcomes between patients who underwent MT based on HCT ± CTA (HCT- group) versus additional including CT or MR perfusion scan (HCT+ group). Design/Methods: Case records of all patients who underwent MT at our center between Jun 2012 - Jun 2017 were reviewed. Patient demographics, risk factors, presentation, pretreatment scan findings, treatment times and clinical outcomes were compared. Favorable outcome is defined as mRS of 2 or less at 90-days. Results: A total of 528 patients were identified, of which 46.4% were male. There were 385 (72.9%) patients who underwent MT based on findings on HCT or CTA (HCT-); while the remaining 143 (27.1%) also underwent additional CTP (121/528; 22.9%) or MRI perfusion (22/528; 4.2%) prior to MT (HCT+). Median age (73 vs 72, p=0.1) and baseline ASPECT scores (8.4 vs. 8.3, p=0.5) were comparable. The HCT- patients had higher NIHSS (17.8 vs. 15.3, p&lt;0.01) and presented earlier with faster onset-to-onsite arrival time (241 vs. 476 minutes, p&lt;0.01). Also, rate of TICI 2b/3 recanalization was higher in the HCT- group (82.8 vs 71.5, p&lt;0.01); however favorable outcome rates were comparable (44.6 vs 47.4, p=0.6). Conclusions: Our findings suggest that HCT ± CTA based MT selection may achieve similar outcomes as compared to more advanced perfusion based neuroimaging protocols. Further prospective studies are warranted.

Abstract WMP14: e-ASPECTS Improves Sensitivity to Early Ischemic Injury on Acute Computed Tomography Scans

Background: ASPECTS (Alberta Stroke Program Early CT Score) is a validated scoring system for assessment of early ischemic change (EIC) on CT head scans, which can be used to guide patient management and improve diagnostic accuracy. Detection of EIC can be challenging particularly for less experienced clinicians. e-ASPECTS software uses machine learning algorithms to support physicians in detecting EIC, which can be quantified using the ASPECTS score. Hypothesis: e-ASPECTS shortens time for CT scan assessment and improves agreement with reference standard ASPECTS when compared to blinded assessment. Methods: 26 clinicians (including 11 radiologists, 6 junior and 7 consultant stroke physicians, and 2 non-specialist physicians) independently scored 2560 ASPECTS regions from 64 patients for signs of EIC on non-contrast CT brain scans. These were acquired within 4.5 hours of stroke onset. A familiarization training set of 5 patients was used prior to scoring. Images were randomized to manual or software assistance. After two weeks images were rescored using the alternative method. Scorers were blinded to clinical symptoms. Reference standard scores were defined by an independent neuroradiologist with information on clinical symptoms, access to 24h follow-up, and with CT perfusion or MRI scans when available. Results: Mean NIHSS was 11. Mean time to score scans fell by 34% (45s, 2:12 to 1:27, mm:ss) using e-ASPECTS assistance. Rater agreement with ground truth was greatest in the radiologist cohort, but performance improved across all clinician categories using e-APSECTS assistance (radiology kappa: 0.26 to 0.38). Sensitivity to EIC improved by a factor of two across all clinician groups using e-ASPECTS assistance, and this was most marked for less experienced physicians. Conclusion: In acute ischemic stroke e-ASPECTS assisted analysis increased accuracy and reduced time for detection of EIC. Routine assistance of non-contrast CT interpretation has the potential to reduce treatment times and improve accuracy across clinicians and sites.

Quantitatively detecting postictal hypoperfusion in patients with focal epilepsy using CT perfusion: Determining cross-modality comparisons and electrode artifacts

BackgroundWe previously showed that CT perfusion (CTP) and arterial spin labelled (ASL) MRI can localize the seizure onset zone in humans via postictal perfusion patterns. As a step towards improving the feasibility/ease of collecting postictal CBF data, we determined whether EEG electrodes need to be removed for CTP data collection and whether a cross-modality comparison between baseline ASL and postictal CTP data is possible. New methodFive patients with epilepsy underwent postictal CTP scanning. Three patients had an interictal ASL scan; one patient had both an ASL and CTP interictal scan. Postictal CTP maps were quantitatively compared to 1) ASL maps averaged from 100 healthy controls, 2) each patient’s baseline ASL map and 3) each patient’s baseline CTP map. To assess for electrode artifacts, a phantom and one patient underwent CTP scanning with EEG electrodes in place. The acquired scans were assessed for artifacts and for postictal hypoperfusion. ResultsFocal postictal hypoperfusion was observable only in intra-modality comparisons (CTP to CTP) and not in cross-modality comparisons (CTP to ASL). EEG electrodes produced streaking artifact that decreased image quality and precluded quantitative analysis. Comparison with existing methods(s)An intra-modality comparison of baseline CTP to postictal CTP was the only comparison method that showed localized hypoperfusion. ConclusionsQuantitative comparison between postictal CTP and baseline ASL scans is not feasible. Postictal hypoperfusion can be detected by CTP only when two CTP scans are collected and when metallic EEG electrodes are removed.

Antitumor effect of curcumin liposome after transcatheter arterial embolization in VX2 rabbits

ABSTRACTBackground: Hypoxia may affect the therapeutic efficacy of transcatheter arterial embolization (TAE), which is widely used in nonsurgical hepatocellular carcinoma (HCC). Liposomal curcumin can exert anticancer effect. Our purpose is to explore the antitumor effect of liposomal curcumin on the HCC after TAE.Methods: The HepG2 cells were cultured under hypoxic condition (1% O2) and then treated with curcumin liposome. Cell viability, apoptosis and cell cycle were respectively measured by CCK-8 and a flow cytometry. The VX2 rabbits were randomly distributed into three groups: control group with saline embolization, TAE group with lipiodol embolization and curcumin liposome group with curcumin liposome and lipiodol embolization. MRI and CT perfusion scanning were performed after embolization. The hepatocyte apoptosis was measured by the terminal deoxyribonucleotidyl transferse-mediated dUTP nick-end labelling (TUNEL). The vascular endothelial growth factor (VEGF) and microvessel density (MVD) were measured by immunohistochemical. RT-PCR and Western blot were performed to examine mRNA and protein levels.Results: By regulating the apoptosis-related molecules, curcumin liposome obviously inhibited the cell viability and promoted the apoptosis in G1 phase. Curcumin liposome reduced the tumor size and alleviated neoplasia in VX2 rabbits. Curcumin liposome decreased the expressions of MVD and VEGF and increased the apoptosis of liver tissues. The levels of hypoxia-inducible factor-1α (HIF-1α) and survivin were suppressed by curcumin liposome both in hypoxic cells and liver tissues in the VX2 rabbits.Conclusion: Curcumin liposome exerted antitumor effect by regulating the proliferation- and apoptosis-related molecules. Curcumin liposome suppressed the HIF-1α and survivin levels and inhibited the angiogenesis in VX2 rabbits after TAE.

CT Perfusion for Identification of Patients at Risk for Delayed Cerebral Ischemia during the Acute Phase after Aneurysmal Subarachnoid Hemorrhage: A Meta-analysis.

It has been acknowledged that delayed cerebral ischemia (DCI) can be diagnosed by computed tomography perfusion (CTP) when it occurs following aneurysmal subarachnoid hemorrhage (aSAH); however, the clinical role of CTP in the prediction of DCI remains unclear. We performed a meta-analysis to investigate the role of CTP in the identification of patients at risk for DCI during the acute phase (<4 days) after aSAH. Relevant articles were systematically searched for analysis on PubMed, EMBASE, and Cochrane databases. The best CTP parameter or the definition of abnormal CTP scan result were collected, and the data with the greatest overall predictive value for DCI was extracted to assess the strength of association between a positive CTP result and an impending DCI. In addition, pooled estimates of sensitivity and specificity were determined. Three relevant articles involving 128 patients were included in the analysis wherein DCI developed in 48 patients (37.5%). The pooled odds ratio was 32.15 (95% CI, 9.92-104.21), suggesting that the patients with a positive CTP test in the acute phase after aSAH were approximately 32 times as likely to develop DCI compared with those without aSAH. The pooled sensitivity and specificity of CTP for detecting impending DCI after aSAH was 65% (95% CI: 0.49-0.78) and 91% (95% CI: 0.83-0.96). CTP can detect abnormal brain perfusion before the occurrence of DCI. This may allow close monitoring and preemptive therapy for improvement in the prognosis in patients with aSAH.

Advances in Imaging and Automated Quantification of Malignant Pulmonary Diseases: A State-of-the-Art Review.

Quantitative imaging in lung cancer is a rapidly evolving modality in radiology that is changing clinical practice from a qualitative analysis of imaging features to a more dynamic, spatial, and phenotypical characterization of suspected lesions. Some quantitative parameters, such as the use of 18F-FDG PET/CT-derived standard uptake values (SUV), have already been incorporated into current practice as it provides important information for diagnosis, staging, and treatment response of patients with lung cancer. A growing body of evidence is emerging to support the use of quantitative parameters from other modalities. CT-derived volumetric assessment, CT and MRI lung perfusion scans, and diffusion-weighted MRI are some of the examples. Software-assisted technologies are the future of quantitative analyses in order to decrease intra- and inter-observer variability. In the era of "big data", widespread incorporation of radiomics (extracting quantitative information from medical images by converting them into minable high-dimensional data) will allow medical imaging to surpass its current status quo and provide more accurate histological correlations and prognostic value in lung cancer. This is a comprehensive review of some of the quantitative image methods and computer-aided systems to the diagnosis and follow-up of patients with lung cancer.

Hybrid Surgery for Internal Carotid Artery Revascularization

The management of chronic complete internal carotid artery (ICA) occlusion (COICA) has been challenging. Endovascular procedures have been performed with variable success and risks, depending on the type of occlusion and distal revascularization. We present a novel hybrid procedure to recanalize the ICA when previous endovascular interventions have failed or been deemed too risky. Two patients presented with symptomatic COICA after maximal medical management. They were deemed at high risk of endovascular intervention and/or previous endovascular attempts had failed. Thus, they had indications for a hybrid procedure. A hybrid technique was used to create a stump by surgical endarterectomy, followed by recanalization using an endovascular approach via femoral access. We have described the technique in detail. Postoperative computed tomography perfusion scanning showed normalization of the mean transient time, cerebral blood volume, and cerebral blood flow compared with the preoperative findings. Cerebral angiography showed successful recanalization of the ICA. Neither patient experienced any complications. A hybrid technique is feasible and should be considered for patients with COICA in whom maximal medical management has failed and who have a high-risk profile for endovascular intervention or in whom previous endovascular attempts have failed.

Assessment of tumour response after stereotactic ablative radiation therapy for lung cancer: A prospective quantitative hybrid 18F‐fluorodeoxyglucose‐positron emission tomography and CT perfusion study

Stereotactic ablative radiotherapy (SABR) is a guideline-recommended treatment for inoperable stage I non-small cell lung cancer (NSCLC), but imaging assessment of response after SABR is difficult. The goal of this study was to evaluate imaging-based biomarkers of tumour response using dynamic 18 F-FDG-PET and CT perfusion (CTP). Thirty-one patients with early-stage NSCLC participated in this prospective correlative study. Each underwent dynamic 18 F-FDG-PET/CTPstudies on a PET/CT scanner pre- and 8weeks post-SABR. The dynamic 18 F-FDG-PET measured the tumour SUVmax , SUVmean and the following parameters: K1 , k2 , k3 , k4 and Ki , all using the Johnson-Wilson-Lee kinetic model. CTP quantitatively mapped BF, BV, MTT and PS in tumours and measured largest tumour diameter. Since free-breathing was allowed during CTP scanning, non-rigid image registration of CT images was applied to minimize misregistration before generating the CTP functional maps. Differences between pre- and post-SABR imaging-based parameters were compared. Tumour size changed only slightly after SABR (median 26mm pre-SABR vs. 23mm post-SABR; P=0.01). However, dynamic 18 F-FDG-PET and CTP study showed substantial and significant changes in SUVmax , SUVmean , k3 , k4 and Ki . Significant decreases were evident in SUVmax (median 6.1 vs. 2.6; P<0.001), SUVmean (median 2.5 vs. 1.5; P<0.001), k3 (relative decrease of 52%; P=0.002), Ki (relative decrease of 27%; P=0.03), whereas there was an increase in k4 (+367%; P<0.001). Hybrid 18 F-FDG-PET/CTP allowed the response of NSCLC to SABR to be assessed regarding metabolic and functional parameters. Future studies are needed, with correlation with long-term outcomes, to evaluate these findings as potential imaging biomarkers of response.

Whole tumor kinetics analysis of 18F-fluoromisonidazole dynamic PET scans of non-small cell lung cancer patients, and correlations with perfusion CT blood flow

BackgroundTo determine the relative abilities of compartment models to describe time-courses of 18F-fluoromisonidazole (FMISO) tumor uptake in patients with advanced stage non-small cell lung cancer (NSCLC) imaged using dynamic positron emission tomography (dPET), and study correlations between values of the blood flow-related parameter K1 obtained from fits of the models and an independent blood flow measure obtained from perfusion CT (pCT).NSCLC patients had a 45-min dynamic FMISO PET/CT scan followed by two static PET/CT acquisitions at 2 and 4-h post-injection. Perfusion CT scanning was then performed consisting of a 45-s cine CT.Reversible and irreversible two-, three- and four-tissue compartment models were fitted to 30 time-activity-curves (TACs) obtained for 15 whole tumor structures in 9 patients, each imaged twice. Descriptions of the TACs provided by the models were compared using the Akaike and Bayesian information criteria (AIC and BIC) and leave-one-out cross-validation. The precision with which fitted model parameters estimated ground-truth uptake kinetics was determined using statistical simulation techniques. Blood flow from pCT was correlated with K1 from PET kinetic models in addition to FMISO uptake levels.ResultsAn irreversible three-tissue compartment model provided the best description of whole tumor FMISO uptake time-courses according to AIC, BIC, and cross-validation scores totaled across the TACs. The simulation study indicated that this model also provided more precise estimates of FMISO uptake kinetics than other two- and three-tissue models.The K1 values obtained from fits of the irreversible three-tissue model correlated strongly with independent blood flow measurements obtained from pCT (Pearson r coefficient = 0.81). The correlation from the irreversible three-tissue model (r = 0.81) was stronger than that from than K1 values obtained from fits of a two-tissue compartment model (r = 0.68), or FMISO uptake levels in static images taken at time-points from tracer injection through to 4 h later (maximum at 2 min, r = 0.70).ConclusionsTime-courses of whole tumor FMISO uptake by advanced stage NSCLC are described best by an irreversible three-tissue compartment model. The K1 values obtained from fits of the irreversible three-tissue model correlated strongly with independent blood flow measurements obtained from perfusion CT (r = 0.81).

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.

Higher admission fasting plasma glucose levels are associated with a poorer short-term neurologic outcome in acute ischemic stroke patients with good collateral circulation

In this retrospective study, we sought to delineate the collateral circulation status of acute ischemic stroke patients by CT perfusion and evaluate 90-day modified Rankin Scale (mRS) scores of patients with good or poor collaterals and its correlation with admission fasting plasma glucose (FPG). We enrolled acute ischemic stroke patients who presented to our hospital 4.5h within an onset of the first episode between January 2009 and December 2015. Neurological assessment was performed using the 90-day mRS scores (0-2 for a favorable and 3-6 for an unfavorable neurologic outcome). Relative filling time delay (rFTD) was evaluated by CT perfusion scan. The primary outcomes were 90-day mRS scores stratified by good (rFTD ≤ 4s) versus poor collateral circulation (rFTD > 4s). Totally 270 patients were included, and 139 (51.5%) patients achieved a favorable neurologic outcome. One hundred eighty-five (68.5%) patients had good collateral circulation. Significantly greater portions of patients with good collateral circulation (60.5%, 112/185) achieved a favorable neurologic outcome compared to those with poor collateral circulation (31.8%, 27/85) (P < 0.05). Patients with good collateral circulation achieving a favorable neurologic outcome had significantly lower baseline FPG (6.6 ± 1.96) than those with good collateral circulation achieving an unfavorable neurologic outcome (8.12 ± 4.02; P = 0.002). Spearman correlation analysis showed that rFTD significantly correlated with 90-day mRS scores (adjusted r = 0.258; P < 0.001) and admission FPG (r = 0.286; P < 0.001). Higher admission FPG levels are associated with significantly higher rates of unfavorable neurologic outcome of acute ischemic stroke patients with good collateral circulation. FPG and rFTD may serve as useful predictors of short-term patient outcome and could be used for risk stratification in clinical decision making.

Computed Tomography Perfusion Imaging for the Diagnosis of Hepatic Alveolar Echinococcosis.

Alveolar echinococcosis (AE) is a rare life-threatening parasitic infection. Computed tomography perfusion (CTP) imaging has the potential to provide both quantitative and qualitative information about the tissue perfusion characteristics. The purpose of this study was the examination of the characteristic features and feasibility of CTP in AE liver lesions. CTP scanning was performed in 25 patients who had a total of 35 lesions identified as AE of the liver. Blood flow (BF), blood volume (BV), portal venous perfusion (PVP), arterial liver perfusion (ALP), and hepatic perfusion indexes (HPI) were computed for background liver parenchyma and each AE lesion. Significant differences were detected between perfusion values of the AE lesions and background liver tissue. The BV, BF, ALP, and PVP values for all components of the AE liver lesions were significantly lower than the normal liver parenchyma (p<0.01). We suggest that perfusion imaging can be used in AE of the liver. Thus, the quantitative knowledge of perfusion parameters are obtained via CT perfusion imaging.

Abstract 81: Time From Imaging to Endovascular Reperfusion Predicts Outcome in Acute Stroke

Objective: This study aims to describe the relationship between CT perfusion-to-reperfusion time and the probability of functional independence in a cohort of patients undergoing endovascular therapy for acute ischemic stroke. Methods: We included data from the CT Perfusion to predict Response in Ischemic Stroke Project (CRISP) in which all patients underwent a baseline CT perfusion (CTP) scan prior to endovascular therapy. Patients were included if they had a mismatch on their baseline CT perfusion scan and achieved successful endovascular reperfusion. Patients with mismatch were categorized into ‘target mismatch’ and ‘malignant mismatch’ profiles, according to the volume of their Tmax&gt;10s lesion volume (target mismatch &lt;100 mL; malignant mismatch &gt;100 mL). We investigated the impact of CTP-to-reperfusion times on probability of achieving functional independence (mRS 0-2) at day 90 and radiographic outcomes at day 5. Results: Of 156 included patients, 108 (59%) had the target mismatch profile, and 48 (26%) had the malignant mismatch profile. In patients with the target mismatch profile, CTP-to-reperfusion time showed no association with functional independence (p=0.84), whereas in patients with malignant mismatch profile, CTP-to-reperfusion time was strongly associated with lower probability of functional independence (OR=0.08, p=0.003). Compared to patients with target mismatch, those with the malignant mismatch profile had significantly more infarct growth (90 [49-166] vs. 43 [18-81] mL, p=0.006) and larger final infarct volumes (110 [61-155 vs. 48 [21-99] mL, p=0.001]). Conclusion: Patients with the target mismatch and malignant mismatch profile respond differently to time delays between baseline imaging and endovascular reperfusion; those with the malignant profile demonstrate a more rapid decline in favorable clinical outcomes and have greater infarct growth.

Evaluating patients for thrombectomy.

The treatment of acute ischemic stroke patients with a proximal large vessel occlusion (LVO) in the anterior circulation has seen tremendous advances initially with the demonstration of the substantial benefit of thrombectomy within 6-h of stroke onset and then with the demonstration of thrombectomy in carefully selected patients up to 24-h from onset. In both the early and late time windows, imaging played an important role in patient selection, especially in the later time window trials where very strict imaging inclusion criteria were employed to identify patients with a small/moderate sized ischemic core on computed tomography perfusion scanning and diffusion-weighted magnetic resonance imaging. In clinical practice, it is important to identify LVO patients quickly so several scoring scales have been developed to help route appropriate patients to a thrombectomy capable center. The recently reported thrombectomy trials left many unanswered questions such as do patients with more distal vessel occlusions benefit, do patients with LVO and mild clinical deficits benefit from thrombectomy, what is the largest extent of baseline ischemic core that still benefits from thrombectomy and what is the best approach to anesthesia with thrombectomy. These questions and other are being addressed in ongoing and future clinical trials that will likely expand the indications and safety for this powerfully effective therapy and also determine if neuroprotection is synergistic with thrombectomy.

Perfusion Computer Tomography Assessment of the Effect of Angiotensin II On Blood Flow Distribution in Rabbits with Intrarenal VX2 Tumors

Background/Aims: Unlike other organs, which only have one set of capillary network, the renal microvasculature consists of two sets of capillary network series connected by efferent arterioles. Angiotensin II constricts the efferent glomerular artery. Hence, renal tumor blood flow (BF) distribution may be different from tumors in other organs. This study aims to investigate the effects of angiotensin II on the hemodynamics of intrarenal VX2 tumors using perfusion computed tomography(CT). Methods: Twenty-four male New Zealand white rabbits were randomly divided into three groups: groups A (blank controls), group B (negative controls), and group C (angiotensin II-treated animals). Group B and C were established to the model of intrarenal VX2 tumors. Furthermore, perfusion CT of the kidney was performed in each group. Prior to perfusion CT scan in group C, the mean arterial blood was elevated to 150-160 mmHg by angiotensin II. The BF, blood volume (BV), mean transit time (MTT), capillary permeability-surface area product (PS), and relative permeability-surface area product (RPS) of tumors and renal tissues were calculated. Results: Compared with normal renal cortex tissues in group A, the BF, BV and PS values of tumors in group B were significantly lower, MTT was prolonged and RPS increased. Compared with group B, only the RPS of these tumors increased from 83.23 ± 29.17% to 120.94 ± 31.84% by angiotensin II infusion. Angiotensin II significantly increased the RPS value of the renal cortex distant from the tumor (CDT) and the right renal cortex (RRC). Conclusions: Perfusion CT can accurately observe the influence of angiotensin II on normal and tumor BF in kidneys. This clarifies the effect of angiotensin II on intrarenal tumor hemodynamics.