Time-to-Maximum of the Tissue Residue Function Improves Diagnostic Performance for Detecting Distal Vessel Occlusions on CT Angiography

Amukotuwa, Shalini A.; Wu, Albert T.; Zhou, Kevin; Page, Inna; Brotchie, Peter; Bammer, Roland

doi:10.3174/ajnr.a6891

Cited by 19 publications

(17 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…15 In fact, small emboli and distal vessel occlusions are often not detected on CT and CTA, though CTP has helped to increase diagnostic sensitivity. 16,17 Patients who do not have a stroke but have imaging findings suggestive of an alternative pathology can undergo a more comprehensive MR imaging examination later if further sequences or better spatial resolution is required for diagnosis.…”

Section: Overcoming the Icm Shortagementioning

confidence: 99%

“…We have shown that distal vessel occlusions and other diseases causing hemodynamic abnormalities can be detected much faster and with greater confidence than on CTA alone. 16,17 This added diagnostic capability is critical to our clinical referrers, who rely on it to guide decisions on distal vessel thrombectomy, thrombolysis beyond 4.5 hours, and patient discharge instead of admission for further work-up if CTP findings are normal. We think that after reducing the ICM of our multimodal CT Code Stroke protocol from 130 to 60 mL; directing Code Stroke in-hours to MR imaging; and having attendings instead of trainees requesting CE studies, our ICM for CTP studies can be well-justified in the interest of patient care.…”

Section: Overcoming the Icm Shortagementioning

confidence: 99%

See 1 more Smart Citation

Navigating Supply Chain Disruptions of Iodinated Contrast Agent for Neuroimaging and How Business Intelligence Can Help the Decision Process

Bammer

Amukotuwa

2022

AJNR Am J Neuroradiol

Self Cite

View full text Add to dashboard Cite

A recent coronavirus disease 2019-related shutdown of the main production facility of iohexol in China has led to massive shortages of iodinated contrast material across the globe. This shortage has also jeopardized neuroimaging. In this article, we describe remedies to reduce iodinated contrast material use for stroke imaging, which is its primary use in neuroimaging, that we have implemented in our hospital network.ABBREVIATIONS: BI ¼ Business Intelligence; CE ¼ contrast-enhanced; coronavirus disease ¼ COVID; ECR ¼ endovascular clot retrieval; ICM ¼ iodinated contrast material; Tmax ¼ time-to-maximum T he latest knock-on effect of the coronavirus disease 2019 (COVID-19) pandemic is a global shortage of iodinated contrast medium (ICM) triggered by the shutdown of GE Healthcare's main production facility of iohexol (Omnipaque; GE Healthcare) during the latest lockdown in Shanghai at the end of March 2022. The combination of the company's Just-in-Time inventory management and lean production strategies that afforded competitive pricing ($0.13/mL for our institution) and GE's large global market share of ICM has led to a massive disruption in the global supply of ICM, which caught many of us by surprise. With stock levels dwindling and unclear information on when the factory will return to full capacity or make up for the production shortfall, many hospitals are scrambling to source more ICM from elsewhere. This unusual sudden demand, in turn, leads to an additional squeeze on the ICM supply chain. Several professional interest groups, including the American College of Radiology 1 and the American Society of Hospital Pharmacists, 2 have issued guidance documents on how to address the current ICM shortage, including various strategies for conservation of contrast material for those diagnostic tests and interventions that are time-critical and without which patients would die or have considerable morbidity. A recent clinical perspective in the American Journal of Roentgenology highlighted several broad strategies to conserve ICM at imaging facilities. 3 This perspective focusses on the most frequent indication for contrastenhanced (CE) CT in neuroimaging: Code Stroke.

show abstract

Section: Overcoming the Icm Shortagementioning

confidence: 99%

Section: Overcoming the Icm Shortagementioning

confidence: 99%

Navigating Supply Chain Disruptions of Iodinated Contrast Agent for Neuroimaging and How Business Intelligence Can Help the Decision Process

Bammer

Amukotuwa

2022

AJNR Am J Neuroradiol

Self Cite

View full text Add to dashboard Cite

show abstract

“…CT perfusion (CTP) maps, generally used to determine the presence of mismatch,5 6 also provide useful information which improves the detection of distal arterial occlusions on CTA 7–9. Time-to-maximum of the tissue residue function (Tmax) is used to identify areas of hypoperfusion and has demonstrated its usefulness in identifying intracranial occlusions or severe stenosis, especially for distal medium VO 9…”

Section: Introductionmentioning

confidence: 99%

Systematic CT perfusion acquisition in acute stroke increases vascular occlusion detection and thrombectomy rates

Olivé‐Gadea

Requena

Diaz³

et al. 2021

J NeuroIntervent Surg

View full text Add to dashboard Cite

BackgroundIn patients with stroke, current guidelines recommend non-invasive vascular imaging to identify intracranial vessel occlusions (VO) that may benefit from endovascular treatment (EVT). However, VO can be missed in CT angiography (CTA) readings. We aim to evaluate the impact of consistently including CT perfusion (CTP) in admission stroke imaging protocols.MethodsFrom April to October 2020 all patients admitted with a suspected acute ischemic stroke underwent urgent non-contrast CT, CTA and CTP and were treated accordingly. Hypoperfusion areas defined by time-to-maximum of the tissue residue function (Tmax) >6 s, congruent with the clinical symptoms and a vascular territory, were considered VO (CTP-VO). In addition, two experienced neuroradiologists blinded to CTP but not to clinical symptoms retrospectively evaluated non-contrast CT and CTA to identify intracranial VO (CTA-VO).ResultsOf the 338 patients included in the analysis, 157 (46.5%) presented with CTP-VO (median Tmax >6s: 73 (29–127) mL). CTA-VO was identified in 83 (24.5%) of the cases. Overall CTA-VO sensitivity for the detection of CTP-VO was 50.3% and specificity was 97.8%. Higher hypoperfusion volume was associated with increased CTA-VO detection (OR 1.03; 95% CI 1.02 to 1.04). EVT was performed in 103 patients (30.5%; Tmax >6s: 102 (63–160) mL), representing 65.6% of all CTP-VO. Overall CTA-VO sensitivity for the detection of EVT-VO was 69.9% and specificity was 95.3%. Among patients who received EVT, the rate of false negative CTA-VO was 30.1% (Tmax >6s: 69 (46–99.5) mL).ConclusionSystematically including CTP in acute stroke admission imaging protocols may increase the diagnosis of VO and rate of EVT.

show abstract

“…M4, A3/A4, and P3 has become feasible, and although it still lacks evidence is probably the next frontier of EVT. 12,13 Such DVOs are likely to be considered for EVT, especially in patients with disabling neurological deficit ineligible for IVT. This emphasizes the importance of fast and accurate DVO detection.…”

mentioning

confidence: 99%

“…The identification of DVOs may be challenging due to their small caliber, large number, and lower resolution compared with large vessels. 12 Systematic manual interrogation of these vessels is complex and time-consuming. The authors show that the use of Tmax increased the rate of DVO detection, the level of confidence, and the speed of interpretation.…”

mentioning

confidence: 99%

CT Perfusion: More Than What You Thought

Molad

2021

AJNR Am J Neuroradiol

View full text Add to dashboard Cite

A cute stroke treatment has dramatically changed in the past decade. Boundaries are crossed, and previous axioms are no longer relevant. The results of the DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention with Trevo (DAWN) and Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE-3) trials, 1,2 examining endovascular thrombectomy (EVT) in the late timeframe (6-24 hours from stroke onset), have thrust perfusion imaging into the evaluation of acute stroke protocol. 3 The primary purpose of CTP is to distinguish salvageable tissue from infarct core and thus improve patient selection for EVT. [3][4][5] It is now widely used as part of an acute stroke CT protocol. However, many stroke centers worldwide routinely perform CTP only for patients beyond the early timeframe. This is in accordance with the recent acute stroke guidelines, recommending CTP in the late (6-24 hour) timeframe. 6 CTP offers other diagnostic utilities. 7 First, CTP may help differentiate ischemic stroke from stroke mimics, including seizure, migraine aura, and conversion disorder. [7][8][9] Although the suspicion for a stroke mimic should not be based solely on CTP, it may add supportive data and help clinicians better diagnose these elusive cases. Second, CTP may contribute valuable information for the selection of candidates for EVT and intravenous thrombolysis (IVT), despite a low NIHSS score. 3 The NIHSS gives much weight to motor function and dominant hemisphere. However, various infarcts may result in neurologic sequelae, not fully revealed by the NIHSS. 10 These patients may greatly benefit from IVT in case a penumbral lesion is identified. Third, CTP can demonstrate the severity of hypoperfusion in the presence of carotid occlusion or dissection and thus help determine the need for reperfusion therapy. 7,11 In this issue of the American Journal of Neuroradiology, Amukotuwa et al 12 examined the use of CTP to aid in interpretation of CTA for distal vessel occlusion (DVO) identification. They demonstrated that the use of time-to-maximum (Tmax) maps significantly improved the diagnostic performance for detecting DVO.Detection of DVO has great importance. The field of endovascular thrombectomy is rapidly emerging, and evidence is growing regarding the beneficial effect of EVT on distal M2 occlusions. 13 Furthermore, EVT targeting very distal occlusions including M3/

show abstract

Time-to-Maximum of the Tissue Residue Function Improves Diagnostic Performance for Detecting Distal Vessel Occlusions on CT Angiography

Cited by 19 publications

References 23 publications

Navigating Supply Chain Disruptions of Iodinated Contrast Agent for Neuroimaging and How Business Intelligence Can Help the Decision Process

Navigating Supply Chain Disruptions of Iodinated Contrast Agent for Neuroimaging and How Business Intelligence Can Help the Decision Process

Systematic CT perfusion acquisition in acute stroke increases vascular occlusion detection and thrombectomy rates

CT Perfusion: More Than What You Thought

Contact Info

Product

Resources

About