CT Perfusion Studies Research Articles

CT perfusion to measure venous outflow in acute ischemic stroke in patients with a large vessel occlusion

BackgroundRobust venous outflow (VO) profiles, measured by degree of venous opacification on pre-thrombectomy CT angiography (CTA) studies, are strongly correlated with favorable outcomes in patients with large vessel occlusion acute...

Secondary Benefits of Microsurgical Intervention on the Vertebral Artery (V1 Segment) for Refractory Vertebrobasilar Insufficiency: Alleviation of Parkinsonism-Like Symptoms

ObjectiveTo investigate the outcomes of micro-neurosurgical interventions on V1 segment of vertebral artery (VA) in patients with refractory vertebrobasilar insufficiency (VBI) due to dolicoarteriopathy and external compressions and to assess the secondary benefits of Parkinsonism-like symptoms. MethodsRetrospective analysis encompassed 101 patients treated for VA dolicoarteriopathy or compression-related refractory VBI from 2016-2023. Of these, 16 patients exhibited drug-resistant Parkinsonism-like symptoms. The diagnostic evaluation included cerebral CT/MR angiography or DSA and brain CT or MR perfusion studies, corroborated by preoperative and 6- and 12-month postoperative MDS-UPDRS Part 3 assessments. Data was analyzed through Turkey's 'E-nabız' system, employing Stata16 for statistical scrutiny. ResultsA significant reduction in MDS-UPDRS scores was observed (preoperative: 26.75 ± 10.91; 6 months: 23.09 ± 9.24; 12 months: 22.5 ± 8.73; P<0.001). Postoperative follow-up denoted that 43.7% of patients ceased medication, and 50% reduced antiparkinsonian drugs. The micro-neurosurgical approach resulted in complete remission of VBI-related symptoms in 84.6% of patients, with the rest showing partial or marked improvement. At six months post-operation, perfusion studies revealed posterior border zone or cerebellar perfusion enhancements in 81% (13 out of 16) of patients, with full symptom resolution, while the remaining 19% (3 out of 16) showed partial perfusion and clinical improvements, particularly in regions supplied by the posterior cerebellar artery (PCA) or posterior inferior cerebellar artery (PICA). The absence of operative mortality and minimal transient morbidities underscored the procedure's safety. ConclusionMicroneurosurgery for VA anomalies in refractory VBI patients, particularly those with concomitant parkinsonian-like syndromes, has demonstrated potential in symptom remission and medication reduction.

Elevated cortical blood flow insufficiency volume as a predictor of adverse outcomes in aneurysmal subarachnoid hemorrhage: a large prospective quantitative computed tomography perfusion study

PurposeEarly hypoperfusion changes exist in patients with aneurysmal subarachnoid hemorrhage (aSAH). We aimed to investigate a readily obtainable quantitative computed tomography perfusion (CTP) parameter that could assist in quickly identifying patients at risk of delayed cerebral ischemia (DCI) and poor 90-day functional outcomes on admission. MethodsWe prospectively collected data between 2021.04 and 2022.12. Preoperative CTP data were post-processed using RAPID software. The cortical blood flow insufficiency (CBFI) was defined as Time-to-maximum > 4.0 s. Patients were categorized into four groups according to CBFI volume distribution. To minimize differences among the groups, we employed stabilized inverse probability of treatment weighting (sIPTW). The primary outcome was DCI and poor 90-day functional outcomes (modified Rankin Scale, 3–6) was the secondary outcome. Multivariable Cox or Logistic analysis were performed to estimate the association between CBFI volume and the study outcomes, both before and after sIPTW. ResultsAt baseline, the mean (SD) age of the 493 participants was 55.0 (11.8) years, and 299 (60.6%) were female. One hundred and seven participants with DCI and eighty-six participants with poor 90-day functional outcomes were identified. After sIPTW, CBFI volume demonstrated a significant association with DCI (Cox regression: Group 4 versus Group 1, HR 3.69, 95% CI 1.84–7.01) and poor 90-day functional outcomes (Logistic regression: Group 4 versus Group 1, OR 4.61, 95% CI 2.01–12.50). ConclusionIn this study, an elevated preoperative CBFI volume was associated with adverse outcomes in aSAH patients. More well-designed studies are needed to confirm this association.

Sporadic Hemiplegic Migraine: Hypoperfusion Demonstrated by Susceptibility-Weighted Magnetic Resonance Imaging and Computed Tomography Perfusion Study

Sporadic Hemiplegic Migraine: Hypoperfusion Demonstrated by Susceptibility-Weighted Magnetic Resonance Imaging and Computed Tomography Perfusion Study

A Teleradiology System for Early Ischemic and Hemorrhagic Stroke Evaluation and Management

Abstract Purpose Stroke is a cardinal cause of death and disability globally. It is an emergency condition where the rapidity of diagnosis is directly linked to the outcome. “Imaging is Brain” is, therefore, an important concept. The early diagnosis of stroke is crucial not only in guiding its effective treatment but also in estimating prognosis. This study aims to provide perspective on the implementation of international teleradiology in stroke evaluation, management, and care. Methods A dedicated international teleradiology stroke network has been evaluated in our study between March 2019 and July 2022 where the interpretation and analysis of the computed tomography (CT) scans of the patients from distant hospitals in United States were performed by teleradiologists via high-quality Digital Imaging and Communications in Medicine (DICOM)-image transfer through a cloud-based radiology information system/picture archival and communication system platform RADspa. Results Over a period of three and a half years, starting from March 2019, a total of 30,406 CT scans of 19,342 patients from 96 hospitals of 15 states in the United States were interpreted and reported by board-certified radiologists empaneled by Teleradiology Solutions. The mean report turnaround time for all noncontrast CT studies was 9.97 minutes at 95% confidence interval (CI: 9.89–10.05); for CT angiogram studies, it was 20.57 minutes 95% CI (20.38–20.77); and for CT perfusion studies, it was 13.72 minutes 95% CI (13.42–14.03). Conclusion A dedicated international teleradiology stroke network designed in our study allowed for transmission, prioritization, evaluation, and management of CT cases performed in the setting of acute stroke in the study population. The results of our investigation indicate that teleradiology provides an effective solution for early diagnosis/interpretation of CT examinations performed internationally in the setting of acute stroke. This may further be used as a model or template for the development of a nationwide stroke network within our own country.

Pancreatic CT perfusion: quantitative meta-analysis of disease discrimination, protocol development, and effect of CT parameters

BackgroundThis study provides a quantitative meta-analysis of pancreatic CT perfusion studies, investigating choice of study parameters, ability for quantitative discrimination of pancreatic diseases, and influence of acquisition and reconstruction parameters on reported results.MethodsBased on a PubMed search with key terms ‘pancreas’ or ‘pancreatic,’ ‘dynamic’ or ‘perfusion,’ and ‘computed tomography’ or ‘CT,’ 491 articles published between 1982 and 2020 were screened for inclusion in the study. Inclusion criteria were: reported original data, human subjects, five or more datasets, measurements of pancreas or pancreatic pathologies, and reported quantitative perfusion parameters. Study parameters and reported quantitative measurements were extracted, and heterogeneity of study parameters and trends over time are analyzed. Pooled data were tested with weighted ANOVA and ANCOVA models for differences in perfusion results between normal pancreas, pancreatitis, PDAC (pancreatic ductal adenocarcinoma), and non-PDAC (e.g., neuroendocrine tumors, insulinomas) and based on study parameters.ResultsReported acquisition parameters were heterogeneous, except for contrast agent amount and injection rate. Tube potential and slice thickness decreased, whereas tube current time product and scan coverage increased over time. Blood flow and blood volume showed significant differences between pathologies (both p < 0.001), unlike permeability (p = 0.11). Study parameters showed a significant effect on reported quantitative measurements (p < 0.05).ConclusionsSignificant differences in perfusion measurements between pathologies could be shown for pooled data despite observed heterogeneity in study parameters. Statistical analysis indicates most influential parameters for future optimization and standardization of acquisition protocols.Critical relevance statementQuantitative CT perfusion enables differentiation of pancreatic pathologies despite the heterogeneity of study parameters in current clinical practice.Graphical abstract

P.089 A literature search using titles and key terms was conducted for articles containing brain death ancillary testing diagnosis, and CTP as primary focus

Background: Ancillary testing assist in the diagnosis of brain death. While traditionally, lack of blood flow (BF) in the intracranial arteries constitutes conclusive evidence that the brain is dead, there is apparent discrepancy between the BF, and sufficient cerebral perfusion; In 15% of patients with confirmed clinical diagnosis of brain death, BF is still preserved. In these patients, cerebral perfusion is significantly impaired suggesting that cerebral perfusion rather than BF more accurately assesses brain function. We aim to present a history of brain death, its pathophysiology, and ancillary tests utilized for its diagnosis- specifically CT Perfusion studies. Methods: A literature search using titles and key terms was conducted for articles containing brain death ancillary testing diagnosis, and CTP as primary focus. Results: Across selected studies, CTP diagnosed brain death with 100% positive predictive value, as none of the patients were proven not-dead on follow-up. The early prediction of mortality outcome in these patients with proven high mortality rate may help decisions for withdrawal of life support. It may also facilitate procurement of organs for transplants. Conclusions: Although clinical assessment is the gold standard method of brain death determination, CTP has shown promising results that could alter our current clinical approach.

Preoperative symptoms of depression, anxiety, and cognitive impairment in glioma patients: A cerebral perfusion CT study.

Glioma patients have varying degrees of psychiatric symptoms, which severely affect the quality of life of patients and their families. The present study investigated the correlation between preoperative psychiatric symptoms and local cerebral perfusion parameters of in glioma patients. The depression, anxiety, and cognitive impairment (CI) scores of 39 patients were assessed separately, and all of the patients underwent a preoperative perfusion computed tomography scan. This study found that: (1) The incidence of preoperative symptoms of depression, anxiety, and CI was 46.15%, 48.72%, and 25.64%, respectively. (2) Cerebral blood volume (CBV) (lesion-sided [LS] occipital lobe white matter [WM] and parietal lobe WM and normal-sided temporal lobe WM), permeability surface (PS) (LS temporal lobe gray matter [GM] and parietal lobe WM) in the depression group were significantly decreased (p<.05). (3) CBV (LS occipital lobe WM), cerebral blood flow (LS parietal lobe GM, centrum ovale and frontal lobe WM and normal-sided frontal lobe WM, temporal lobe WM and parietal lobe WM), and mean transition time (MTT) (normal-sided frontal lobe WM and temporal lobe WM) in the anxiety group were significantly increased (p<.05). (4) CBV (LS temporal lobe GM), MTT (LS anterior limb of internal capsule), and PS (LS thalamus) in the CI group were significantly increased (p<.05). This study showed that glioma patients had different levels of psychological distress in glioma patients before surgery, which may be related to the changes in brain perfusion caused by the tumor.

System-wide implementation of Computed Tomography Perfusion (CTP) Imaging for Acute Stroke: Impact on Quality, Safety and Outcomes (P7-5.009)

<h3>Objective:</h3> This study aims to assess the impact of CTP acquisition in regional hospitals on quality metrics, functional and safety outcomes in patients with LVO. <h3>Background:</h3> The utility of CTP imaging in spoke hospitals to determine eligibility for MT remains controversial. <h3>Design/Methods:</h3> Consecutive adult patients treated for LVO after initially presenting to regional spokes between Jan 2021 to Dec 2021 were included. CTP was added to acute stroke imaging protocol in April 2021. Demographics, NIHSS, quality metrics, imaging parameters, and functional outcomes were compared between patients who did vs. did not undergo CTP at a regional hospital. Core volume growth and rate (ml/min) was assessed for patients with CTP data both at the regional and at the CSC. <h3>Results:</h3> CTP studies were performed on 1083 in regional patients and LVO was confirmed in 29 (2.6%) patients. Of these, 14 were transferred to CSC without CTP at the regional and 15 were transferred with CTP at regional hospital. Age (p=0.44), NIHSS (p=0.08), door to thrombolysis (p=0.13), door-in-door-out (p=0.17) times, successful reperfusion (TICI IIb/III; p=0.83) and hemorrhagic transformation (ECASS III; p=0.49) did not differ significantly between the groups. Rates of mRS 0–2 were similar in both groups (p=0.85). In subgroup analysis of patients who underwent CTP both at the regional facility and CSC (n=15), median core volume grew significantly but slowly (0[0, 7] ml vs. 7 [0, 14] ml, p=0.022), at a median rate of 0 [0, 0.07] ml/min. No patients were excluded from thrombectomy due to core growth. <h3>Conclusions:</h3> Our study suggests that regional site perfusion imaging does not have a significant impact on process times, quality metrics and outcomes. Core volume grows during interfacility transfers without an impact on eligibility for MT. A larger study is needed to assess the role perfusion imaging in regional spokes. <b>Disclosure:</b> Miss Abarca has nothing to disclose. Dr. Potluri has nothing to disclose. Dr. Miller has nothing to disclose. Mrs. Stowe has nothing to disclose. Dr. Wideman has nothing to disclose. Dr. Tsai has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Cerenovus. Tricia Tubergen has received personal compensation in the range of $0-$499 for serving as a Consultant for Medtronic. Todd Mulderink has nothing to disclose. Dr. Min has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Abbott . Dr. Min has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Medtronic . Dr. Wees has nothing to disclose. Dr. Khan has nothing to disclose. Dr. Ahrar has nothing to disclose. Justin Singer has received personal compensation in the range of $50,000-$99,999 for serving as a Consultant for Stryker. Justin Singer has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Medtronic. Justin Singer has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Ceronovus. Justin Singer has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Nico. The institution of Justin Singer has received research support from Stryker Grant. Paul Mazaris has nothing to disclose. John Oostema has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Life EMS. The institution of John Oostema has received research support from Spectrum Health. John Oostema has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant with MDHHS. The institution of Dr. Khan has received research support from NINDS. The institution of Dr. Khan has received research support from Genentech. The institution of Dr. Khan has received research support from Spectrum Health-MSU alliance. Dr. Khan has received research support from NIH.

ADDED UTILITY OF COMPUTED TOMOGRAPHY PERFUSION STUDY IN THE ASSESSMENT OF EARLY ISCHEMIC STROKE IN COMPARISON WITH NONCONTRAST COMPUTED TOMOGRAPHY - A PROSPECTIVE OBSERVATIONAL STUDY

Objective: 1. T o study the added utility of computed tomography perfusion study in the assessment of early ischemic stroke in comparison with non-contrast computed tomography. 2. To study the role of computed tomography perfusion study in deciding thrombolytic treatment/ therapeutic protocols aimed at reversing the cerebral ischemic insult. Conclusions and Results: It was observed that 15 (46.68%) patients were in the 61-70 years of age group followed by 8 (25%) in the age group of 51-60 years. The mean age of the patients was 58.87 ±12.14 years. Ÿ Females were affected more i.e. 18 (56.25%) compared to the male patients 14 (43.75%). Ÿ Most observed co-morbid condition was hypertension in 9 (28.13%) patients followed by hypertension and diabetes in 7 (21.87%) patients and diabetes in 6 (18.75%) patients. Ÿ Among the study participants 4 (12.50%) were smokers followed by 6 (18.75%) were alcoholic and smokers &amp; alcoholic (15.62%) respectively. Ÿ It was observed that the symptoms of palsy were present among 23 (71.88%) patients Ÿ The most commonly observed time of onset of symptoms was 3-5 hours in 23 (71.88%) patients followed by 1-3 hours (21.87%) and &gt;5 hours in 2 (6.25%) patients. Ÿ NCCT ndings observed was denite signs of stroke in 12 (37.5%) patients followed by suspected signs of stroke on NCCT (25%) Ÿ It was observed that no sign of stroke was observed in 12 (37.5%) patients. Ÿ CT perfusion ndings observed was increased mean transient time (MTT) in all (100%) patients followed by decreased blood ow in all (100%) patients. It was observed that cerebral blood volume decreased in 12 (37.5%) patients, increased in 8 (25%) and normal in 12 (37.5%) patients. Ÿ The correlation of NCCT and CT perfusion ndings observed that out of total 32 patients NCCT study identies 20 patients while all 32 patients were identied by CT perfusion study with sensitivity of 100%. Ÿ CT perfusion provides early diagnosis of ischemic stroke thus helps in management of stroke patients. Inference : The present study concludes that CT-perfusion had more sensitivity compared to NCCT in identifying early ischemic stroke. CT perfusion has additional utility in management of early ischemic stroke. CT Perfusion study provides important information to the neurologist and neuro-interventionalist when evaluating patients for endovascular reperfusion therapy by identifying the size of core infarction and penumbra

Arteriovenous cerebral blood flow correlation in moderate-to-severe traumatic brain injury: CT perfusion study

IntroductionThe relationship between arterial and venous blood flow in moderate-to-severe traumatic brain injury (TBI) is poorly understood. The research questionwas to compare differences in perfusion computed tomography (PCT)-derived arterial and venous cerebral blood flow (CBF) in moderate-to-severe TBI as an indication of changes in cerebral venous outflow patterns referenced to arterial inflow. Material and methodsModerate-to-severe TBI patients (women 53; men 74) underwent PCT and were stratified into 3 groups: I (moderate TBI), II (diffuse severe TBI without surgery), and III (severe TBI after the surgery). Arterial and venous CBF were measured by PCT in both the internal carotid arteries (CBFica) and the confluence of upper sagittal, transverse, and straight sinuses (CBFcs). ResultsIn group I, CBFica on the left and right sides were significantly correlated with each other (p < 0.0001) and with CBFcs (p = 0.048). In group II, CBFica on the left and right sides were also correlated (P < 0.0000001) but not with CBFcs. Intracranial pressure reactivity (PRx) and CBFcs were correlated (p = 0.00014). In group III, CBFica on the side of the removed hematoma was not significantly different from the opposite CBFica (P = 0.680) and was not correlated with CBFcs. Discussion and conclusionThe increasing severity of TBI is accompanied by a rising uncoupling between the arterial and venous CBF in the supratentorial vessels suggesting a shifting of cerebral venous outflow.

Changes of Arterial and Venous Cerebral Blood Flow Correlation in Moderate-to-Severe Traumatic Brain Injury: A CT Perfusion Study.

We compared differences in perfusion computed tomography (PCT)-derived arterial and venous cerebral blood flow (CBF) in moderate-to-severe traumatic brain injury (TBI) as an indication of changes in cerebral venous outflow patterns referenced to arterial inflow. Moderate-to-severe TBI patients (women 53; men 74) underwent PCT and were stratified into 3 groups: I (moderate TBI), II (diffuse severe TBI without surgery), and III (diffuse severe TBI after the surgery). Arterial and venous CBF was measured by PCT in both the middle cerebral arteries (CBFmca) and the upper sagittal sinus (CBFuss). In group I, CBFmca on the left and right sides were significantly correlated with each other (p<0.0001) and with CBFuss (p=0.048). In group II, CBFmca on the left and right sides were also correlated (p<0.0000001) but not with CBFuss. Intracranial pressure reactivity (PRx) and CBFuss were correlated (p=0.00014). In group III, CBFmca on the side of the removed hematoma was not significantly different from the opposite CBFmca (p=0.680) and was not correlated with CBFuss. Conclusions: The increasing severity of TBI is accompanied by an impairment of the correlation between the arterial and venous CBF in the supratentorial vessels suggesting shifting in arterial and venous CBF in severe TBI associated with increased ICP reflected by PRx.

Electrocardiographic Gating and Cerebral Perfusion Computed Tomography Option-Set Prevalence and Utilization Data From 62 Institutions in the United States.

To provide the radiology community with data to address the question: "Compared with peer institutions, is my institution efficiently using its electrocardiographic (ECG) gating and cerebral perfusion-capable computed tomography (CT) scanners?" In this retrospective study, we analyze 6 months of scanner utilization data from 62 institutions (299 locations, 507 scanners) to identify scanners capable of performing ECG gating and perfusion CT studies. We report the number of ECG gating/perfusion-capable scanners and locations as a function of the total number of locations and scanners in each institution. We additionally regress the number of ECG-gated and perfusion examinations on (1) the number of locations/scanners capable of performing these examinations and (2) the fraction of the institution's CT examination volume that requires ECG gating or perfusion. We provide look-up tables so an institution can compare its ECG-gated/perfusion examination volume to other institutions with similar ECG-gated/perfusion examination fractions and capable scanners. We detected an effect of both ECG-gating examination fraction and the number of ECG gating-capable scanners on ECG-gated examination volume ( χ21 = 77.5 [ P < 0.001] and χ21 = 64.2 [ P < 0.001], respectively). Similar results were obtained for perfusion examination fraction and perfusion-capable scanners as they relate to perfusion examination volume ( χ21 = 51.6 [ P < 0.001] and χ21 = 45.2 [ P < 0.001], respectively). The number of ECG gating/perfusion-capable scanners and locations within an institution were found to positively correlate with both the total number of locations and scanners within an institution ( P < 0.001 for all hypothesis tests). The study provides multi-institutional data on ECG gating and perfusion examination volumes that can be used to inform CT purchasing decisions.

Feasibility of deconvolution-based multiphase CT angiography perfusion maps in acute ischemic stroke: Simulation and concordance with CT perfusion

ObjectivesIntegration of CT perfusion (CTP) with requisite non-contrast CT and CT angiography (CTA) stroke imaging may allow efficient stroke lesion volume measurement. Using surrogate images from CTP, we simulated the feasibility of using multiphase CTA (mCTA) to generate perfusion maps and assess target mismatch profiles. Materials and methodsPatients with acute ischemic stroke who received admission CTP were included in this study. Four CTP images (surrogate mCTA, one pre-contrast and three post-contrast, starting at the arterial peak then at 8 s intervals) were selected according to the CTP arterial time-density curve to simulate non-contrast CT and mCTA images. Cerebral blood flow (CBF) and Tmax maps were calculated using the same model-based deconvolution algorithm for the standard CTP and surrogate mCTA studies. Infarct and penumbra were delineated with CBF < 20% and Tmax > 6 s threshold, respectively. Classification accuracy of surrogate mCTA target mismatch (infarct <70 ml; penumbra ≥15 ml; mismatch ratio ≥1.8) with respect to standard CTP was assessed. Agreement between infarct and penumbra volumes from standard CTP and surrogate mCTA maps were evaluated by Bland-Altman analysis. ResultsOf 34 included patients, 28 had target mismatch and 6 did not by standard CTP. Accuracy of classifying target mismatch profiles with surrogate mCTA was 79% with respect to that from standard CTP. Mean ± standard deviation of differences (standard CTP minus surrogate mCTA) of infarct and penumbra volumes were 9.8 ± 14.8 ml and 20.1 ± 45.4 ml, respectively. ConclusionsSurrogate mCTA ischemic lesion volumes agreed with those from standard CTP and may be an efficient alternative when CTP is not practical.

Rule-based natural language processing for automation of stroke data extraction: a validation study.

Data extraction from radiology free-text reports is time consuming when performed manually. Recently, more automated extraction methods using natural language processing (NLP) are proposed. A previously developed rule-based NLP algorithm showed promise in its ability to extract stroke-related data from radiology reports. We aimed to externally validate the accuracy of CHARTextract, a rule-based NLP algorithm, to extract stroke-related data from free-text radiology reports. Free-text reports of CT angiography (CTA) and perfusion (CTP) studies of consecutive patients with acute ischemic stroke admitted to a regional stroke center for endovascular thrombectomy were analyzed from January 2015 to 2021. Stroke-related variables were manually extracted as reference standard from clinical reports, including proximal and distal anterior circulation occlusion, posterior circulation occlusion, presence of ischemia or hemorrhage, Alberta stroke program early CT score (ASPECTS), and collateral status. These variables were simultaneously extracted using a rule-based NLP algorithm. The NLP algorithm's accuracy, specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were assessed. The NLP algorithm's accuracy was > 90% for identifying distal anterior occlusion, posterior circulation occlusion, hemorrhage, and ASPECTS. Accuracy was 85%, 74%, and 79% for proximal anterior circulation occlusion, presence of ischemia, and collateral status respectively. The algorithm confirmed the absence of variables from radiology reports with an 87-100% accuracy. Rule-based NLP has a moderate to good performance for stroke-related data extraction from free-text imaging reports. The algorithm's accuracy was affected by inconsistent report styles and lexicon among reporting radiologists.

Abstract No. 504 Preliminary experience of computed tomography perfusion study for patients with peripheral arterial disease using intra-procedural intra-arterial contrast administration

The purpose of this study is to describe a preliminary experience of a catheter-directed foot computed tomography (CT) perfusion study for critical limb ischemia (CLI) patients and compare the findings between pre and post angioplasty.

Assessment of brain tumors by magnetic resonance dynamic susceptibility contrast perfusion-weighted imaging and computed tomography perfusion: a comparison study.

To investigate the association and agreement between magnetic resonance dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) and computed tomography perfusion (CTP) in determining vascularity and permeability of primary and secondary brain tumors. DSC-PWI and CTP studies from 97 patients with high-grade glioma, low-grade glioma and solitary brain metastasis were retrospectively reviewed. Normalized cerebral blood flow (nCBF), cerebral blood volume (nCBV), capillary transfer constant (nK2) and permeability surface area product (nPS) values were obtained. Variables among groups were compared, and correlation and agreement between DSC-PWI and CTP were tested. All DSC-PWI and CTP parameters were higher in high-grade than in low-grade gliomas (p < 0.01 and p < 0.001). Metastases had greater DSC-PWI nCBV (p < 0.05), nCTP-CBF (p < 0.05), nCTP-CBV (p < 0.01) and nCTP-PS (p < 0.0001) than low-grade gliomas and more elevated nCTP-PS (p < 0.01) than high-grade gliomas. The correlation was strong between DSC-PWI nCBF and CTP nCBF (r = 0.79; p < 0.00001) and between DSC-PWI nCBV and CTP nCBV (r = 0.83; p < 0.00001), weaker between DSC-PWI nK2 and CTP nPS (r = 0.29; p < 0.01). Bland-Altman plots indicated that the agreement was strong between DSC-PWI nCBF and CTP nCBF, good between DSC-PWI nCBV and CTP nCBV and poorer between DSC-PWI nK2 and CTP nPS. DSC-PWI and CTP CBF and CBV maps were comparable and interchangeable in the assessment of tumor vascularity, unlike DSC-PWI K2 and CTP PS maps that were more discordant in the analysis of tumor permeability. CTP could be an alternative method to quantify tumor neoangiogenesis when MRI is not available or when the patient does not tolerate it.

Low-dose CT Perfusion with Sparse-view Filtered Back Projection in Acute Ischemic Stroke

Radiation dose associated with computed tomography (CT) perfusion (CTP) may discourage its use despite its added diagnostic benefit in quantifying ischemic lesion volume. Sparse-view CT reduces scan dose by acquiring fewer X-ray projections per gantry rotation but is contaminated by streaking artifacts using filtered back projection (FBP). We investigated the achievable dose reduction by sparse-view CTP with FBP without affecting CTP lesion volume estimations. Thirty-eight consecutive patients with acute ischemic stroke and CTP were included in this simulation study. CTP projection data was simulated by forward projecting original reconstructions with 984 views and adding Gaussian noise. Full-view (984 views) and sparse-view (492, 328, 246, and 164 views) CTP studies were simulated by FBP of simulated projection data. Cerebral blood flow (CBF) and time-to-maximum of the impulse residue function (Tmax) maps were generated by deconvolution for each simulated CTP study. Ischemic volumes were measured by CBF<30% relative to the contralateral hemisphere and Tmax > 6 s. Volume accuracy was evaluated with respect to the full-view CTP study by the Friedman test with post hoc multiplicity-adjusted pairwise tests and Bland-Altman analysis. Friedman and multiplicity-adjusted pairwise tests indicated that 164-view CBF < 30%, 246- and 164-view Tmax > 6 s volumes were significantly different to full-view volumes (p < 0.001). Mean difference ± standard deviation (sparse minus full-view lesion volume) ranged from -1.0 ± 2.8 ml to -4.1 ± 11.7 ml for CBF < 30% and -2.9 ± 3.8 ml to -12.5 ± 19.9 ml for Tmax > 6 s from 492 to 164 views, respectively. By ischemic volume accuracy, our study indicates that sparse-view CTP may allow dose reduction by up to a factor of 3.

Should Primary Stroke Centers Perform Advanced Imaging?

Should Primary Stroke Centers Perform Advanced Imaging?

Identification of hemodynamically significant coronary artery disease with stress myocardial blood flow ratio by dynamic CT perfusion studies

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Coronary computed tomographic angiography (CTA) is an accepted noninvasive tool with high diagnostic accuracy for the evaluation of coronary artery disease (CAD). However, coronary CTA is limited in that it does not provide information on the hemodynamic relevance of coronary artery stenosis. Therefore, to determine the potential benefit of future coronary revascularization, a functional assessment is often required. A protocol combining coronary computed tomographic angiography (CTA) and CTP can provide a simultaneous assessment of both coronary artery ischemia and anatomy. Purpose This study sought to evaluate the diagnostic accuracy of stress myocardial blood flow ratio (SFR), a novel parameter derived from stress dynamic computed tomographic perfusion (CTP), for the detection of hemodynamically significant coronary stenosis. Methods A total of 98 patients (mean age 54.5 ± 10 years) with 128 vessels with either 1- or 2-vessel disease, scheduled for invasive angiography were included in this study. Stress dynamic CTP was performed followed by coronary CTA using a dual-source computed tomographic system. Fractional flow reserve was performed at subsequent invasive angiography to identify hemodynamically significant stenosis. Stress myocardial blood flow ratio (SFR) was defined as the ratio of hyperemic myocardial blood flow (MBF) in an artery with stenosis to hyperemic MBF in a non-diseased artery. The diagnostic accuracy of the SFR index was determined against the reference standard of invasive fractional flow reserve ≤0.80. Results 58 (45.3%) vessels were deemed hemodynamically significant by fractional flow reserve (FFR) measurement. Hyperemic MBF and SFR were lower for vessels with hemodynamically significant lesions (95 ± 32.2 ml/100 ml/min vs. 140.5 ± 30.4 ml/100 ml/min; p &amp;lt; 0.01 for both). When compared with ≥50% stenosis by CTA, the specificity for detecting ischemia by SFR increased from 44% to 92%, while the sensitivity decreased from 93% to 58%. The combination of stenosis ≥50% by CTA and SFR resulted in an area under the curve of 0.9, which was significantly higher compared with hyperemic MBF, area under the curve = 0.79 and p &amp;lt; 0.01. Conclusion Our study concludes that the calculation of SFR by dynamic CTP provides a pioneering and accurate method to identify flow-limiting coronary stenosis. Abstract Figure.