NeuroradiologyDifferentiation of hemorrhage from contrast enhancement using dual-layer spectral CT in patients transferred for acute stroke
Section snippets
Technique and illustrative cases
Spectral CT imaging was performed utilizing a Philips IQon Spectral CT 64 slice scanner (Philips Healthcare, Best, Netherlands): 255 mAs, 120 kVp, pitch = 0.359, gantry rotation time = 330 ms, detector collimation = 64 × 0.625 mm, volume CT dose index = 43.8 mGy. Conventional CT images were reconstructed using an iterative reconstruction algorithm (iDose, Level 2; Philips Healthcare). Spectral images were reconstructed using a spectral reconstruction algorithm (Spectral, level 2). Reconstructed
Case 1
An 84 year-old male with history of atrial fibrillation on anticoagulation presented to an outside hospital with right sided weakness, facial droop, and aphasia. CT angiogram demonstrated a proximal left middle cerebral artery M2 occlusion. The patient was transferred for potential mechanical thrombectomy. Upon arrival, the NIH stroke scale was 24. The initial head CT upon arrival was performed on a Philips IQon CT 256 slice scanner (without spectral imaging) and was obtained approximately 3 h
Case 2
A 93 year-old male with history of atrial fibrillation presented to an outside institution with slurred speech and left sided weakness. CTA of the head performed at the outside institution demonstrated a proximal right middle cerebral artery M2 branch occlusion. Upon arrival, the NIH stroke scale was 16. Initial head CT after arrival was performed on a CT spectral scanner (approximately 3.5 h after the initial CT angiogram examination), and demonstrated acute infarcts within the right temporal
Discussion
Recent clinical trials have demonstrated the benefits of mechanical thrombectomy in patients presenting with late window strokes [[1], [2], [3]]. Consequently, increasing number of patients may be suitable candidates for transfer to a TCC for mechanical thrombectomy. During transfer to a TCC, stroke patients may exhibit a decay in the ASPECTS score [4] or new intracranial hemorrhage. Accordingly, upon arrival to the TCC, immediate imaging evaluation is performed to exclude a large stroke burden
Conclusion
In our experience, acute stroke patients transferred for potential mechanical thrombectomy, may demonstrate parenchymal hyperdensities related to contrast administration at the first institution. Virtual non-contrast images are helpful in distinguishing parenchymal contrast enhancement from hemorrhage in this setting. TCC may consider adopting a workflow in which acute stroke patients transferred for potential thrombectomy are initially imaged with a dual-energy or dual-layer spectral CT
References (11)
Eligibility for endovascular trial enrollment in the 6- to 24-hour time window: analysis of a single comprehensive stroke center
Stroke
(2018)Thrombectomy 6 to 24 hours after stroke with a mismatch between deficit and infarct
N Engl J Med
(2018)Thrombectomy for stroke at 6 to 16 hours with selection by perfusion imaging
N Engl J Med
(2018)ASPECTS decay during inter-facility transfer in patients with large vessel occlusion strokes
J Neurointerv Surg
(2017)Optimizing patient selection for endovascular treatment in acute ischemic stroke (SELECT): a prospective, multicenter cohort study of imaging selection
Ann Neurol
(2020)
Cited by (5)
Photon-counting spectral CT reconstruction with sparse and double low-rank components fusion
2023, Biomedical Signal Processing and ControlPotential of dual-layer spectral CT for the differentiation between hemorrhage and iodinated contrast medium in the brain after endovascular treatment of ischemic stroke patients
2021, Clinical ImagingCitation Excerpt :As SPCCT is a promising technique that offers the potential to improve image quality, lower image noise and reduce radiation dose38 it might replace the DLSCT system in the future when applicable for clinical use. The possibility to differentiate between blood and iodinated contrast agent might also be useful in cases where patients received iodinated contrast agent prior to the essential head CT scan within the stroke examination or before the transport to centers capable for thrombectomy, where CT scans might be repeated to exclude secondary hemorrhage.39 Another interesting application of DLSC in the field of neuroradiology might be for tumor diagnostics for the differentiation between hemorrhage and contrast-enhancing tumor parts40 or the differentiation between iodinated contrast agent and calcifications.41
Mechanical thrombectomy beyond the circle of Willis: efficacy and safety of different techniques for M2 occlusions
2022, Journal of NeuroInterventional SurgeryImaging in Stroke Diagnosis and Treatment: An Update
2021, Applied Radiology