Semi-automatic carotid intraplaque hemorrhage detection and quantification on Magnetization-Prepared Rapid Acquisition Gradient-Echo (MP-RAGE) with optimized threshold selection

Co-existing intracranial and extracranial carotid atherosclerosis predicts large-artery atherosclerosis stroke recurrence: a single-center prospective study utilizing combined head-and-neck vessel wall imaging

OBJECTIVES

Intracranial and extracranial plaque features on high-resolution vessel wall imaging (HR-VWI) are associated with large-artery atherosclerosis (LAA) stroke recurrence. However, most studies have focused on a single vascular bed, and the prognostic value of combined intracranial and extracranial plaque features has yet to be studied. This study aimed to investigate the roles of plaque features, plaque number, and co-existing atherosclerosis in predicting stroke recurrence, utilizing combined head-and-neck HR-VWI.

METHODS

From September 2016 to March 2020, participants with acute LAA ischemic strokes were prospectively enrolled and underwent combined head-and-neck HR-VWI. The participants were followed for stroke recurrence for at least 12 months or until a subsequent event occurred. The imaging features at baseline, including conventional and histogram plaque features, plaque number, and co-existing atherosclerosis, were evaluated. Univariable Cox regression analysis and the least absolute shrinkage and selection operator (lasso) method were used for variable screening. Multivariable Cox regression analyses were used to determine the independent risk factors of stroke recurrence.

RESULTS

A total of 97 participants (59 ± 12 years, 63 men) were followed for a median of 30.9 months, and 21 participants experienced recurrent strokes. Multivariable Cox analysis identified co-existing intracranial high signal on T1-weighted fat-suppressed images (HST1) and extracranial carotid atherosclerosis (HR, 6.12; 95% CI, 2.52-14.82; p = 0.001) as an independent imaging predictor of stroke recurrence.

CONCLUSION

Co-existing intracranial HST1 and extracranial carotid atherosclerosis independently predicted LAA stroke recurrence. Combined head-and-neck HR-VWI is a promising technique for atherosclerosis imaging.

CLINICAL RELEVANCE STATEMENT

This prospective study using combined head-and-neck HR-VWI highlighted the necessity of both intracranial culprit plaque evaluation and multi-vascular bed assessment, adding value to the prediction of stroke recurrence.

KEY POINTS

• This study highlighted the necessity of both intracranial culprit plaque evaluation and multi-vascular bed assessment, adding value to the prediction of stroke recurrence. • This prospective study using combined head-and-neck HR-VWI found co-existing intracranial HST1 and extracranial carotid atherosclerosis to be independent predictors of stroke recurrence.

Neovascularization From the Carotid Artery Lumen Into the Carotid Plaque Confirmed by Contrast-Enhanced Ultrasound and Histology

OBJECTIVE

This study was aimed at assessing intraplaque neovessels, focusing on neovascularization from the vascular luminal side using contrast-enhanced ultrasound (CEUS) and determining that this contrast effect indicates that the neovessel is connected to the vessel lumen histopathologically. Whether plaque vulnerability can be assessed more accurately was also investigated.

METHODS

We enrolled consecutive patients with internal carotid artery stenosis who underwent carotid endarterectomy (CEA) and pre-operative CEUS with perflubutane of the carotid arteries. We graded the contrast effect semi-quantitatively from the vascular luminal and adventitial sides. We compared the contrast effect with the pathological findings, especially the neovascularization of the CEA specimens.

RESULTS

In total, 68 carotid arterial atheromatous plaques (47 symptomatic) were analyzed. Symptomatic plaques were significantly correlated with stronger contrast effects from the luminal side than from the adventitial side (p = 0.0095). Microbubbles from the luminal side appeared to flow mainly into the plaque shoulder. The contrast effect value for the plaque shoulder and neovessel density were significantly correlated (ρ = 0.35, p = 0.031). Neovessel density was significantly higher in symptomatic than in asymptomatic plaques (56.2 ± 43.7/mm2 and 18.1 ± 15.2/mm2, respectively, p < 0.0001). Serial histological sections of CEA specimens in a symptomatic plaque with a strong contrast effect from the luminal side revealed multiple neovessels fenestrated to the vessel lumen with endothelial cells, consistent with the CEUS findings.

CONCLUSION

Contrast-enhanced ultrasound can be used to evaluate neovessels originating from the luminal side, histopathologically confirmed in serial sections. Symptomatic vulnerable plaque is correlated more significantly with intraplaque neovascularization from the luminal side than with neovascularization from the adventitia.

Atherosclerotic carotid plaque characteristics vary with time from ischemic event: A multicenter, prospective magnetic resonance vessel wall imaging registry study

Recent studies report that the rate of recurrent stroke is highest in the stages immediately following cerebral infarction and decreases over time in patients with atherosclerotic carotid stenosis. The purpose of this study was to identify temporal differences in early stage carotid plaque components from acute cerebrovascular ischemic events using carotid MRI. Carotid plaque images were obtained on 3 T MRI from 128 patients enrolled in MR-CAS. Among the 128 subjects, 53 were symptomatic and 75 asymptomatic. The symptomatic patients were classified into three groups based on interval from onset of symptoms to the date of the carotid MRI (Group <14 days; 15-30 days; and > 30 days). The volume of each plaque component was identified and quantified from MR images. The presence of juxtaluminal loose matrix/inflammation (LM/I) was identified as a possible indicator of inflammation on the luminal side. Plaque components were compared between groups using the Wilcoxon rank-sum or the Chi-square test. Patient characteristics and carotid plaque morphology were similar among all four groups. The median volume of LM/I in Group >30 days was significantly lower than in other groups (0 mm3 vs 12.3 mm3 and 18.1 mm3; p = 0.003). In addition, the prevalence of juxtaluminal LM/I decreased over time (ptrend = 0.002). There were no statistically significant differences in other plaque components between the symptomatic groups. The volume of LM/I was significantly smaller in Group >30 days and prevalence of juxtaluminal LM/I in the atherosclerotic carotid plaque was high in the early stages after events. This suggests that carotid plaques undergo rapid evolution after an acute cerebrovascular ischemic event.

Morphological and Compositional Features of Chronic Internal Carotid Artery Occlusion in MR Vessel Wall Imaging Predict Successful Endovascular Recanalization

Background: We sought to determine if the morphological and compositional features of chronic internal carotid artery occlusion (CICAO), as assessed by MR vessel wall imaging (MR-VWI), initially predict successful endovascular recanalization. Methods: Consecutive patients with CICAO scheduled for endovascular recanalization were recruited. MR-VWI was performed within 1 week prior to surgery for evaluating the following features: proximal stump morphology, extent of occlusion, occlusion with collapse, arterial tortuosity, the presence of hyperintense signals (HIS) and calcification in the occluded C1 segment. Multivariate logistic regression was used to identify features associated with technical success and construct a prediction model. Results: Eighty-three patients were recruited, of which fifty-seven (68.7%) were recanalized successfully. The morphological and compositional characteristics of CICAO were associated with successful recanalization, including occlusions limited to C1 and extensive HIS, as well as the absence of extensive calcification, absence of high tortuosity, and absence of artery collapse. The MR CICAO score that comprised the five predictors showed a high predictive ability (area under the curve: 0.888, p < 0.001). Conclusion: the MR-VWI characteristics of CICAO predicted the technical success of endovascular recanalization and may be leveraged for identifying patients with a high probability of successful recanalization.

The Frequency of Carotid Intraplaque Hemorrhage on Vessel Wall Imaging in Patients With Retinal Artery Occlusion: A Cross-Sectional Prevalence Study

BACKGROUND

Intraplaque hemorrhage (IPH) in a carotid artery plaque viewed on vessel wall imaging has been shown to be associated with ischemic stroke. Whether such an association between carotid IPH and retinal artery occlusion (RAO) exists remains unknown.

METHODS

This was a cross-sectional prevalence study. Medical and imaging records of all patients who underwent neck MRA with plaque imaging sequences at our institution from 2015 to 2020 were retrospectively reviewed. Fourteen patients with confirmed RAO and plaque imaging performed within 6 weeks of presentation were included. A group of 211 patients without a prior ischemic event (RAO, stroke, etc.) with plaque imaging were used as controls. A single artery from control patients was randomly selected. The prevalence of IPH and degree of ipsilateral carotid stenosis were compared between RAO and control patients. Multiple regression analysis was performed to determine independent associations between variables and RAO.

RESULTS

Five patients (35.7%) with RAO had imaging evidence of ipsilateral IPH in contrast to 7 of 211 (3.3%) patients in the control group (odds ratio [OR]: 16.2, 95% confidence interval [95% CI]: 4.3-61.1, P = 0.0002). Of the 5 patients with RAO and ipsilateral IPH, only one (20.0%) was found to ipsilateral carotid stenosis greater than 70%. Carotid IPH was the only variable that was independently associated with RAO (OR: 12.6, 95% CI = 2.2-73.6, P = 0.005).

CONCLUSIONS

Carotid IPH is independently associated with RAO. The use of plaque imaging in the evaluation of patients with acute RAO is therefore supported.

The Effect of Stent Design on Plaque Protrusion after Carotid Artery Stenting

Objective

The association between stent design and post-stent intravascular findings after carotid artery stenting (CAS) was evaluated.

Methods

Among the 79 patients who underwent CAS between March 2016 and June 2020 at our institution, we retrospectively analyzed 65 patients with full post-stent intravascular evaluation by both optical frequency domain imaging and angioscopy. All CAS procedures were performed under the flow reversal method, and the stent selection was determined by each operator's discretion, depending on the vessel anatomy or plaque characteristics. The patient's characteristics, plaque characteristics, ischemic complication, and post-stent intravascular findings (plaque protrusion, vessel wall apposition of stent) were compared between the closed-cell and open-cell stent groups.

Results

The closed-cell group (n = 34) had more high-risk plaques, such as symptomatic lesions or intraplaque hemorrhages, on MRI compared with the open-cell group (n = 31). There was no difference in the rate of ischemic complications between the groups. Although there was no difference in the frequency of plaque protrusion between the two, the maximum height of the protruded plaque was higher in the open-cell group (320 vs. 612 μm, p = 0.003) and incomplete apposition was higher in the closed-cell group (85.3 vs. 6.5%, p <0.0001).

Conclusion

The open-cell stent provided better apposition but had larger plaque protrusion. The need for a new hybrid stent that combines the merits of both open- and closed-cell stents was suggested.

Histological validation of simultaneous non-contrast angiography and intraplaque hemorrhage imaging (SNAP) for characterizing carotid intraplaque hemorrhage

OBJECTIVES

This study sought to validate the performance of simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) imaging in characterizing carotid IPH by histology.

METHODS

Thirty-five patients with carotid atherosclerotic disease (symptomatic 50-70% stenosis or > 70% stenosis) scheduled for carotid endarterectomy underwent 3.0-T carotid MR imaging by acquiring SNAP and magnetization-prepared rapid acquisition gradient-echo (MP-RAGE) sequences. Presence and area of IPH were separately evaluated on SNAP and MP-RAGE images. Presence and area of IPH were also assessed on histology. Agreement between SNAP/MP-RAGE and histology was determined in identify and quantify IPH using Cohen kappa, Spearman correlation, and Bland-Altman analyses.

RESULTS

Of all 35 patients (mean age: 63.1 ± 8.8 years; 27 males), 128 slices with successful registration were eligible for analysis. The accuracy, sensitivity, specificity, and positive and negative predictive values were 86.7%, 85%, 89.6%, 93.2%, and 78.2% for SNAP, and 76.6%, 75%, 79.2%, 85.7%, and 65.5% for MP-RAGE in identification of IPH, respectively. In identification of IPH, the kappa value between SNAP and histology and between MP-RAGE and histology was 0.725 and 0.520, respectively. The correlation between SNAP and histology (r = 0.805, p < 0.001) was stronger than that between MP-RAGE and histology (r = 0.637, p < 0.001) in measuring IPH area. Bland-Altman analysis showed that, in measuring IPH area, the bias of SNAP (1.4 mm², 95% CI: - 0.016 to 2.883) was smaller than that of MP-RAGE (1.7 mm², 95% CI: - 0.039 to 3.430) compared with histology.

CONCLUSIONS

This validation study by histology demonstrates that SNAP sequence better identifies and quantifies carotid intraplaque hemorrhage compared with traditional MP-RAGE sequence.

KEY POINTS

• SNAP imaging showed better agreement with histology compared with MP-RAGE imaging, especially for the IPHs with small size. • SNAP sequence is a more effective tool to identify and quantify carotid IPH than traditional sequence of MP-RAGE that can help clinicians to optimizing the treatment strategy. • The plaque components of rich lipid pools or loose matrix and chronic/old IPH (cholesterol crystals) can lead to false positive and false negative results in SNAP and MP-RAGE imaging for identifying IPH.

PET/MRI of atherosclerosis

Myocardial infarction and stroke are the most prevalent global causes of death. Each year 15 million people worldwide die due to myocardial infarction or stroke. Rupture of a vulnerable atherosclerotic plaque is the main underlying cause of stroke and myocardial infarction. Key features of a vulnerable plaque are inflammation, a large lipid-rich necrotic core (LRNC) with a thin or ruptured overlying fibrous cap, and intraplaque hemorrhage (IPH). Noninvasive imaging of these features could have a role in risk stratification of myocardial infarction and stroke and can potentially be utilized for treatment guidance and monitoring. The recent development of hybrid PET/MRI combining the superior soft tissue contrast of MRI with the opportunity to visualize specific plaque features using various radioactive tracers, paves the way for comprehensive plaque imaging. In this review, the use of hybrid PET/MRI for atherosclerotic plaque imaging in carotid and coronary arteries is discussed. The pros and cons of different hybrid PET/MRI systems are reviewed. The challenges in the development of PET/MRI and potential solutions are described. An overview of PET and MRI acquisition techniques for imaging of atherosclerosis including motion correction is provided, followed by a summary of vessel wall imaging PET/MRI studies in patients with carotid and coronary artery disease. Finally, the future of imaging of atherosclerosis with PET/MRI is discussed.

Quantification of Carotid Intraplaque Hemorrhage: Comparison between Manual Segmentation and Semi-Automatic Segmentation on Magnetization-Prepared Rapid Acquisition with Gradient-Echo Sequences

Purpose: Carotid intraplaque hemorrhage (IPH) increases risk of territorial cerebral ischemic events, but different sequences or criteria have been used to diagnose or quantify carotid IPH. The purpose of this study was to compare manual segmentation and semi-automatic segmentation for quantification of carotid IPH on magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) sequences. Methods: Forty patients with 16–79% carotid stenosis and IPH on MPRAGE sequences were reviewed by two trained radiologists with more than five years of specialized experience in carotid plaque characterization with carotid plaque MRI. Initially, the radiologists manually viewed the IPH based on the MPRAGE sequence. IPH volume was then measured by three different semi-automatic methods, with high signal intensity 150%, 175%, and 200%, respectively, above that of adjacent muscle on the MPRAGE sequence. Agreement on measurements between manual segmentation and semi-automatic segmentation was assessed using the intraclass correlation coefficient (ICC). Results: There was near-perfect agreement between manual segmentation and the 150% and 175% criteria for semi-automatic segmentation in quantification of IPH volume. The ICC of each semi-automatic segmentation were as follows: 150% criteria: 0.861, 175% criteria: 0.809, 200% criteria: 0.491. The ICC value of manual vs. 150% criteria and manual vs. 175% criteria were significantly better than the manual vs. 200% criteria (p < 0.001). Conclusions: The ICC of 150% and 175% criteria for semi-automatic segmentation are more reliable for quantification of IPH volume. Semi-automatic classification tools may be beneficial in large-scale multicenter studies by reducing image analysis time and avoiding bias between human reviewers.

Plaque components segmentation in carotid artery on simultaneous non-contrast angiography and intraplaque hemorrhage imaging using machine learning

PURPOSE

This study sought to determine the feasibility of using Simultaneous Non-contrast Angiography and intraPlaque Hemorrhage (SNAP) to detect the lipid-rich/necrotic core (LRNC), and develop a machine learning based algorithm to segment plaque components on SNAP images.

METHODS

Sixty-eight patients (age: 58±9 years, 24 males) with carotid artery atherosclerotic plaque were imaged on a 3 T MR scanner with both traditional multi-contrast vessel wall MR sequences (TOF, T1W, and T2W) and 3D SNAP sequence. The manual segmentations of carotid plaque components including LRNC, intraplaque hemorrhage (IPH), calcification (CA) and fibrous tissue (FT) on traditional multi-contrast images were used as reference. By utilizing the intensity and morphological information from SNAP, a machine learning based two steps algorithm was developed to firstly identify LRNC (with or without IPH), CA and FT, and then segmented IPH from LRNC. Ten-fold cross-validation was used to evaluate the performance of proposed method. The overall pixel-wise accuracy, the slice-wise sensitivity & specificity & Youden's index, and the Pearson's correlation coefficient of the component area between the proposed method and the manual segmentation were reported.

RESULTS

In the first step, all tested classifiers (Naive Bayes (NB), Support Vector Machine (SVM), Random Forest (RF), Gradient Boosting Decision Tree (GBDT) and Artificial Neural Network (ANN)) had overall pixel-wise accuracy higher than 0.88. For RF, GBDT and ANN classifiers, the correlation coefficients of areas were all higher than 0.82 (p < 0.001) for LRNC and 0.79 for CA (p < 0.001), and the Youden's indexes were all higher than 0.79 for LRNC and 0.76 for CA, which were better than that of NB and SVM. In the second step, the overall pixel-wise accuracy was higher than 0.78 for the five classifiers, and RF achieved the highest Youden's index (0.69) with the correlation coefficients as 0.63 (p < 0.001).

CONCLUSIONS

The RF is the overall best classifier for our proposed method, and the feasibility of using SNAP to identify plaque components, including LRNC, IPH, CA, and FT has been validated. The proposed segmentation method using a single SNAP sequence might be a promising tool for atherosclerotic plaque components assessment.

Semiautomatic carotid intraplaque hemorrhage volume measurement using 3D carotid MRI

BACKGROUND

Presence of intraplaque hemorrhage (IPH) is a known risk factor for stroke and plaque progression. Accurate and reproducible measurement of IPH volume are required for further risk stratification.

PURPOSE

To develop a semiautomatic method to measure carotid IPH volume.

STUDY TYPE

Retrospective.

POPULATION

Patients scheduled for carotid endarterectomy and patients with 16-79% asymptomatic carotid stenosis by ultrasound.

FIELD STRENGTH

3T.

SEQUENCE

Simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) MRI.

ASSESSMENT

A semiautomated volumetric measurement of IPH using signal intensity thresholding of 3D SNAP volume was implemented. Fourteen carotid endarterectomy patients were enrolled to determine the signal intensity threshold of IPH using histology. Thirty-three patients with 16-79% asymptomatic stenosis were scanned twice within 1 month to evaluate reproducibility. The normalized SNAP intensity with the highest Youden index for predicting IPH on histology was used for thresholding. Scan-rescan reproducibility of IPH measurement was assessed using the intraclass correlation coefficient (ICC) and coefficient of variation (CV).

STATISTICAL TESTS

Receiver operating characteristic curve, area under the curve, Cohen's kappa, intraclass correlation coefficient, coefficient of variance (CV), and paired t-test.

RESULTS

IPH detection by the algorithm had substantial agreement with manual review (kappa: 0.92; 95% confidence interval [CI]: 0.83, 1.00) and moderate agreement with histology (kappa: 0.55; 95% CI: 0.34, 0.68). IPH volume measurements by the algorithm were strongly correlated with histology (Spearman's rho = 0.76, P = 0.002). IPH measurements were also reproducible, with ICCs of 0.86 (95% CI: 0.57, 0.96), 0.77 (95% CI: 0.32, 0.94), and 0.99 (95% CI: 0.93, 1.00) for maximum/mean normalized intensity and IPH volume, respectively. The corresponding CVs were 10.6%, 5.2%, and 11.8%.

DATA CONCLUSION

IPH volume measurements on SNAP MRI are highly reproducible using semiautomatic measurement. Level of Evidence 2 Technical Efficacy Stage 2 J. Magn. Reson. Imaging 2019;50:1055-1062.

Journal of Cardiovascular Magnetic Resonance 2017

There were 106 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2017, including 92 original research papers, 3 reviews, 9 technical notes, and 1 Position paper, 1 erratum and 1 correction. The volume was similar to 2016 despite an increase in manuscript submissions to 405 and thus reflects a slight decrease in the acceptance rate to 26.7%. The quality of the submissions continues to be high. The 2017 JCMR Impact Factor (which is published in June 2018) was minimally lower at 5.46 (vs. 5.71 for 2016; as published in June 2017), which is the second highest impact factor ever recorded for JCMR. The 2017 impact factor means that an average, each JCMR paper that were published in 2015 and 2016 was cited 5.46 times in 2017.In accordance with Open-Access publishing of Biomed Central, the JCMR articles are published on-line in continuus fashion and in the chronologic order of acceptance, with no collating of the articles into sections or special thematic issues. For this reason, over the years, the Editors have felt that it is useful to annually summarize the publications into broad areas of interest or theme, so that readers can view areas of interest in a single article in relation to each other and other contemporary JCMR articles. In this publication, the manuscripts are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought within the journal. In addition, I have elected to use this format to convey information regarding the editorial process to the readership.I hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your very best, high quality manuscripts to JCMR for consideration. I thank our very dedicated Associate Editors, Guest Editors, and Reviewers for their efforts to ensure that the review process occurs in a timely and responsible manner and that the JCMR continues to be recognized as the forefront journal of our field. And finally, I thank you for entrusting me with the editorship of the JCMR as I begin my 3rd year as your editor-in-chief. It has been a tremendous learning experience for me and the opportunity to review manuscripts that reflect the best in our field remains a great joy and highlight of my week!

Mathematical modeling of atherosclerotic plaque destabilization: Role of neovascularization and intraplaque hemorrhage

Observational studies have identified angiogenesis from the adventitial vasa vasorum and intraplaque hemorrhage (IPH) as critical factors in atherosclerotic plaque progression and destabilization. Here we propose a mathematical model incorporating intraplaque neovascularization and hemodynamic calculation with plaque destabilization for the quantitative evaluation of the role of neoangiogenesis and IPH in the vulnerable atherosclerotic plaque formation. An angiogenic microvasculature is generated by two-dimensional nine-point discretization of endothelial cell proliferation and migration from the vasa vasorum. Three key cells (endothelial cells, smooth muscle cells and macrophages) and three key chemicals (vascular endothelial growth factors, extracellular matrix and matrix metalloproteinase) are involved in the plaque progression model, and described by the reaction-diffusion partial differential equations. The hemodynamic calculation of the microcirculation on the generated microvessel network is carried out by coupling the intravascular, interstitial and transvascular flow. The plasma concentration in the interstitial domain is defined as the description of IPH area according to the diffusion and convection with the interstitial fluid flow, as well as the extravascular movement across the leaky vessel wall. The simulation results demonstrate a series of pathophysiological phenomena during the vulnerable progression of an atherosclerotic plaque, including the expanding necrotic core, the exacerbated inflammation, the high microvessel density (MVD) region at the shoulder areas, the transvascular flow through the capillary wall and the IPH. The important role of IPH in the plaque destabilization is evidenced by simulations with varied model parameters. It is found that the IPH can significantly speed up the plaque vulnerability by increasing necrotic core and thinning fibrous cap. In addition, the decreased MVD and vessel permeability may slow down the process of plaque destabilization by reducing the IPH dramatically. We envision that the present model and its future advances can serve as a valuable theoretical platform for studying the dynamic changes in the microenvironment during the plaque destabilization.

Review of Journal of Cardiovascular Magnetic Resonance (JCMR) 2015-2016 and transition of the JCMR office to Boston

The Journal of Cardiovascular Magnetic Resonance (JCMR) is the official publication of the Society for Cardiovascular Magnetic Resonance (SCMR). In 2016, the JCMR published 93 manuscripts, including 80 research papers, 6 reviews, 5 technical notes, 1 protocol, and 1 case report. The number of manuscripts published was similar to 2015 though with a 12% increase in manuscript submissions to an all-time high of 369. This reflects a decrease in the overall acceptance rate to <25% (excluding solicited reviews). The quality of submissions to JCMR continues to be high. The 2016 JCMR Impact Factor (which is published in June 2016 by Thomson Reuters) was steady at 5.601 (vs. 5.71 for 2015; as published in June 2016), which is the second highest impact factor ever recorded for JCMR. The 2016 impact factor means that the JCMR papers that were published in 2014 and 2015 were on-average cited 5.71 times in 2016.In accordance with Open-Access publishing of Biomed Central, the JCMR articles are published on-line in the order that they are accepted with no collating of the articles into sections or special thematic issues. For this reason, over the years, the Editors have felt that it is useful to annually summarize the publications into broad areas of interest or themes, so that readers can view areas of interest in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes with previously published JCMR papers to guide continuity of thought in the journal. In addition, I have elected to open this publication with information for the readership regarding the transition of the JCMR editorial office to the Beth Israel Deaconess Medical Center, Boston and the editorial process.Though there is an author publication charge (APC) associated with open-access to cover the publisher's expenses, this format provides a much wider distribution/availability of the author's work and greater manuscript citation. For SCMR members, there is a substantial discount in the APC. I hope that you will continue to send your high quality manuscripts to JCMR for consideration. Importantly, I also ask that you consider referencing recent JCMR publications in your submissions to the JCMR and elsewhere as these contribute to our impact factor. I also thank our dedicated Associate Editors, Guest Editors, and reviewers for their many efforts to ensure that the review process occurs in a timely and responsible manner and that the JCMR continues to be recognized as the leading publication in our field.

Identification of intraplaque haemorrhage in carotid artery by simultaneous non-contrast angiography and intraPlaque haemorrhage (SNAP) imaging: a magnetic resonance vessel wall imaging study

OBJECTIVES

To investigate the usefulness of Simultaneous Non-contrast Angiography and intraPlaque haemorrhage (SNAP) imaging in characterising carotid intraplaque haemorrhage (IPH) compared with magnetisation-prepared rapid acquisition gradient-echo (MP-RAGE) sequence.

METHODS

Fifty-four symptomatic patients (mean age: 63.1 ± 5.7 years, 38 males) with carotid atherosclerosis were recruited and underwent carotid MR imaging. The presence and area of IPH on SNAP and MP-RAGE images were determined. The agreement in identifying IPH and its area between SNAP and MP-RAGE was analysed.

RESULTS

Of 1368 slices with acceptable image quality in 54 patients, 13% and 22.6% were found to have IPH on MP-RAGE and SNAP images, respectively. There was moderate agreement between MP-RAGE and SNAP sequences in identifying IPH (κ = 0.511, p = 0.029). The area of IPH on SNAP images was significantly larger than that on MP-RAGE images (17.9 ± 18.2 mm² vs. 9.2 ± 10.5 mm², p < 0.001). For IPHs detected by SNAP imaging, the area of IPHs also detected by the MP-RAGE sequence was significantly larger than that of IPHs not detected by the MP-RAGE sequence (17.9 ± 19.2 mm² vs. 6.4 ± 6.2 mm², p < 0.001).

CONCLUSION

Compared with the MP-RAGE sequence, SNAP imaging detects more IPHs, particularly for smaller IPHs, suggesting that SNAP imaging might be a more sensitive tool for identification of carotid haemorrhagic plaques.

KEY POINTS

• Moderate agreement was found between SNAP and MP-RAGE in identification of IPH • SNAP imaging might be a more sensitive tool to detect carotid IPHs • Compared with the MP-RAGE sequence, SNAP imaging can detect carotid IPHs with smaller size • SNAP imaging can help clinicians to optimise the treatment strategy.