Ona Wu, Eric Rosenthal, Gaston Cudemus-Deseda, Brian Edlow, Marjorie Villien, Brittany Mills, Joseph Giacino, James Januzzi, Ming Ming Ning, W. Kimberly, William Copen, Pamela Schaefer, David Greer

Cardiac arrest patients in coma after restoration of spontaneous circulation were prospectively studied to determine whether variability in structural connectivity can discriminate patients likely to recover consciousness from those who will not. Compared to healthy controls, cardiac arrest patients overall had significantly  lower values in the following structural connectivity parameters: global efficiency, clustering coefficient, and degree. Cardiac arrest patients who failed to recover alertness had a significantly lower global clustering coefficient compared to patients who woke up. Alterations in structural connectivity may play an important role in predicting recovery and guiding patient management decisions in comatose cardiac arrest patients.

Samantha Ma, Songlin Yu, David Liebeskind, Dandan Yu, Ning Li, Xingfeng Shao, Jeffrey Saver, Noriko Salamon, Danny JJ Wang

An automatic scoring system for assessing reperfusion status based on arterial spin labeled (ASL) perfusion MRI was developed and evaluated for acute ischemic stroke patients who received thrombolysis and/or endovascular treatment. Reperfusion injury is considered to have the same detrimental effects as non-reperfusion, and we applied the ASPECTS model to address the existence of heterogeneity of hypo- and hyper-perfusion despite vessel recanalization. Our newly devised reperfusion scoring system is highly associated with patient functional outcome and provides a useful tool to complement other clinical methods for managing corresponding strategies after treatment.

Ganesh Adluru, Kyler Hodgson, Jennifer Majersik, Lorie Richards, Edward DiBella

Diffusion spectrum imaging (DSI) is a promising tool for estimation of white-matter fiber structure.  DSI also allows for model-based estimation of several microstructure measures.  However, the long data acquisition time associated with DSI limits its application in stroke patients.  Here we combine a simultaneous multi-slice acquisition with an undersampled q-space acquisition and dictionary reconstruction to accelerate DSI.  The two complementary acceleration schemes allow for a rapid 5.5 minute DSI acquisition in stroke subjects.  We used generalized fractional anisotropy and microstructure measures computed from the NODDI model to evaluate the rapid DSI framework in stroke patients.

Jiadi Xu, Kathryn Schunke, Lin Chen, Xiang Xu, Yuguo Li, Guanshu Liu, Shuhui Cai, Raymond Koehler, Jiangyang Zhang, Peter van Zijl, Nauder Faraday

Ischemia in a mouse stroke model was assessed by pH mapping using the on-resonance variable-delay multi-pulse (onVDMP) CEST scheme. In the method, an on-resonance binomial pulse train is applied at the water resonance to achieve high labeling efficiency for fast-exchanging protons. Since the CEST signal intensity for the total fast-exchanging protons is far greater than that of amide protons, high detection sensitivity is expected. The final stroke region determined by the method was verified by histologic analysis.

Grégory Kuchcinski, Fanny Munsch, Renaud Lopes, Jason Su, Antoine Bigourdan, Brian Rutt, Vincent Dousset, Igor Sibon, Thomas Tourdias

In stroke patients, remote thalamic alterations including iron deposition have been reported and attributed to the disruption of cortico-thalamic projections. Nevertheless, secondary thalamic degeneration has never been quantified so far in humans at the nucleus scale and its clinical impact is unknown. By using R2* mapping, we demonstrated (i) that iron accumulates with a focal distribution especially within the medio-dorsal nucleus and the pulvinar, (ii) that such focal thalamic iron accumulation is strongly linked to the initial stroke location, consistent with the known connectivity between thalamic nuclei and cortico-subcortical areas and (iii) is significantly impacting specific cognitive and emotional functions.

Petrice Cogswell, Jeroen Siero, Guillaume Gilbert, Taylor Davis, Allison Scott, Katie Lants, Helen Mahany, Jennifer Watchmaker, Jeroen Hendrikse, Manus Donahue

This work compares vessel wall SNR and CSF suppression from multiple approaches to determine optimal imaging parameters for intracranial VWI at the clinically-available field strength of 3T. T1-weighted TSE acquisition using variable refocusing angle pulse-train and DANTE preparation provides for blood and CSF suppression while maintaining adequate vessel wall SNR. The use of a variable refocusing pulse train with sweep of 40-120° provides improved performance compared to a sweep of 50-120°. Variation of the DANTE flip angle showed that a flip angle of 8° provides good CSF suppression with minimal SNR loss compared to flip angles of 10 and 12°. 

Sachi Okuchi, Yasutaka Fushimi, Tomohisa Okada, Akira Yamamoto, Tsutomu Okada, Takayuki Yamamoto, Katsutoshi Murata, Yuta Urushibata, Kaori Togashi

Compressed sensing (CS) algorithm has been brought into MRI. CS realizes iterative reconstruction of images from incoherently under-sampled data, which leads to shorter acquisition time. A 3D T1-weighted fast spin echo (T1-FSE) scan has been often used for plaque imaging. We compared visualization of carotid plaque and internal carotid artery (ICA) between 3D T1-FSE imaging with SPACE and with a prototype CS SPACE. In the result, CS-T1-SPACE revealed an equivalent visualization compared with T1-SPACE in evaluation of carotid plaque and ICA. CS-T1-SPACE would be useful for the visualization of carotid plaque and ICA.

Arjen Lindenholz, Irene van der Schaaf, Anita Harteveld, Bart van der Worp, Anja Van der Kolk, Jeroen Hendrikse

Intra-arterial treatment (IAT) may damage the arterial vessel wall, which might lead to recurrent thrombosis and distal embolism.In this study the intracranial vessel wall was evaluated in patients with acute ischemic stroke after IAT using high-resolution vessel wall MRI. Thirteen patients underwent both 3T and 7T pre- and postcontrast vessel wall MRI to detect contrast-enhancing lesions. Significantly more enhancing vessel wall lesions and concentric enhancing lesions ipsilateral to IAT were found compared to the contralateral side. The higher number of concentric enhancing lesions ipsilateral to the IAT may be related to the presence of the thrombus and the performed IAT.

Adam de Havenon, Nabeel Chauhan, Seong-Eun Kim, J. Rock Hadley, Ka-Ho Wong, David Tirschwell, Jennifer Majersik, Dennis Parker, J. McNally

Intracranial atherosclerotic enhancement on vessel wall MRI is associated with with symptomatic plaque, but there is insufficient data on the clinical characteristics associated with atherosclerotic enhancement on T1-weighted vessel wall MRI sequences or the relationship between atherosclerotic enhancement and recurrent stroke or TIA.  Our study demonstrates that intracranial atherosclerotic plaque enhancement detected on 3T vessel wall MRI with 3D DANTE T1-SPACE accurately predicts a high risk of early stroke or TIA recurrence, with a potentially modifiable risk factor: elevated serum hemoglobin A1c.

Ying Cai, Le He, Chun Yuan, Huijun Chen, Qiang Zhang, Rui Li, Cheng Li, Xihai Zhao

This study investigated the morphology, compositions and distribution of carotid artery atherosclerotic plaques in asymptomatic elderly population using 3D multicontrast MR vessel wall imaging. The atherosclerotic plaques were found to be prevalent (62.1%) and more than 12% subjects had high risk plaques (HRP) in this study population. Among carotid arteries without luminal stenosis, the prevalence of plaque and HRP was 43.2% and 8.3%, respectively. Benefiting from the 3D vessel wall imaging with large longitudinal coverage, near 14% of subjects had plaques in either distal ICA or proximal CCA segment which cannot be captured by traditional 2D vessel wall imaging.