Craniocervical CT Angiography Research Articles

Super Learner Algorithm for Carotid Artery Disease Diagnosis: A Machine Learning Approach Leveraging Craniocervical CT Angiography.

This study introduces a machine learning (ML) approach to diagnosing carotid artery diseases, including stenosis, aneurysm, and dissection, by leveraging craniocervical computed tomography angiography (CTA) data. A meticulously curated, balanced dataset of 122 patient cases was used, ensuring reproducibility and data quality, and this is publicly accessible at (insert dataset location). The proposed method integrates a super learner model which combines adaptive boosting, gradient boosting, and random forests algorithms, achieving an accuracy of 90%. To enhance model robustness and generalization, techniques such as k-fold cross-validation, bootstrapping, data augmentation, and the synthetic minority oversampling technique (SMOTE) were applied, expanding the dataset to 1000 instances and significantly improving performance for minority classes like aneurysm and dissection. The results highlight the pivotal role of blood vessel structural analysis in diagnosing carotid artery diseases and demonstrate the superior performance of the super learner model in comparison with state-of-the-art (SOTA) methods in terms of both accuracy and robustness. This manuscript outlines the methodology, compares the results with state-of-the-art approaches, and provides insights for future research directions in applying machine learning to medical diagnostics.

Clinical effectiveness of contrast medium injection protocols for 80-kV coronary and craniocervical CT angiography-a prospective multicenter observational study.

Decreasing X-ray tube voltage is an effective way to reduce radiation and contrast dose, especially in non-obese patients. The current study focuses on CTA in non-obese patients to evaluate image quality and feasibility of 80-kV acquisition protocols with varying iodine delivery rates (IDR) and contrast concentrations in routine clinical practice. A prospective observational study in patients ≥ 18years and ≤ 90kg referred for coronary or craniocervical CTA at 10 centers in China (ClinicalTrials.gov: NCT02840903). Patients were divided into four groups: a standard 100-kV protocol (370 mgI/ml, IDR 1.48 gI/s), and three 80-kV protocols (370 mgI/ml, IDR 1.2 gI/s; 300 mgI/ml, IDR 1.2 gI/s; 300 mgI/ml, IDR 0.96gI/s). The primary outcome was contrast opacification of target vascular segments. Secondary outcomes were image quality (contrast-to-noise ratio, signal-to-noise ratio, visual image quality, and diagnostic confidence assessment), radiation, and iodine dose. From July 2016 to July 2017, 1213 patients were enrolled: 614 coronary and 599 craniocervical CTA. The mean contrast opacification was ≥ 300 HU for 80-kV 1.2 gI/s IDR scanned segments; IDR 0.96 gI/s led to lower opacification. Image quality and diagnostic confidence were fair to excellent (≥ 98% of images), despite lower contrast-to-noise ratios and signal-to-noise ratios in 80-kV images. Compared to the standard protocol, 80-kV protocols led to 44-52% radiation dose reductions (p < 0.001) and 19% iodine dose reductions (p < 0.001). Eighty-kilovolt 1.2 gI/s IDR protocols can be recommended for coronary and craniocervical CTA in non-obese patients, reducing radiation and iodine dose without compromising image quality. • Using low-voltage scanning CTA protocols, in which tube voltage and iodine delivery rate are reduced proportionally (voltage: 80kV, IDR: 1.2 gI/s), reduces radiation and contrast dose without compromising image quality in routine clinical practice. • Reducing iodine delivery rate beyond direct proportionality to tube voltage is not beneficial.

Impact of 80 kVp with iterative reconstruction algorithm and low-dose contrast medium on the image quality of craniocervical CT angiography

PurposeTo assess the image quality of 80-kVp craniocervical CT angiography (CCCTA) protocol combined with adaptive statistical iterative reconstruction-V (ASIR-V) and low-dose contrast medium (CM). MethodsA total of 119 patients were randomly divided into three groups. For group A, 120-kVp protocol was followed with 60 ml CM and filtered back projection; for group B, 80-kVp protocol with 60 ml CM and ASIR-V; and for group C, 80-kVp protocol with 45 ml CM and ASIR-V. Both subjective and objective image quality and radiation doses were evaluated. ResultsArterial attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the head, neck, and shoulder regions were significantly higher in groups B and C compared with group A. Group C yielded significantly better subjective image quality than that observed in groups A and B (both p < .05). As compared with group A, effective radiation dose and the iodine load of group C were reduced by 51.4% and 25%, respectively. ConclusionsThe CCCTA protocol with 80 kVp, ASIR-V, and 45 ml of CM injected at 3 ml/s significantly reduced the radiation dose, iodine load, and iodine delivery rate while providing better subjective and objective image quality, including higher arterial enhancement and a higher SNR and CNR compared with the 120-kVp protocol.

The structural properties of carotid arteries in carotid artery diseases – a retrospective computed tomography angiography study

PurposeAim of the study was to find answers to the following questions: What haemodynamic changes may occur in patients with stenotic, aneurysmal, dissection of the carotid artery and its branches? How do these changes differ in patients with normal and carotid disease?Material and methodsIn order to achieve this aim, the cranio-cervical CT angiography images of patients who were referred to our clinic for any reason and received the diagnosis of carotid stenosis, carotid dissection, and extra or intracranial aneurysm were reviewed retrospectively.ResultsSignificant differences were detected in the carotid arteries of normal patients and those with aneurysm and dissection. When normal and aneurismal patients were compared, right and left ICA diameters (p = 0.000, p = 0.002, respectively), total ICA diameters (p = 0.000), carotid left Ø diameters (p = 0.026), right and left total Ø diameters (p = 0.024), and Murray’s and our cosine values of Ø angles (p = 0.001 and p = 0.022, respectively) were found to be different. Also, in a comparison made between normal patients and patients with dissection, right CCA (p = 0.000), ICA (p = 0.001), ECA (p = 0.004) diameters, total CCA (p = 0.001), ICA (p = 0.009), and ECA (p = 0.003) diameters were also found to be different.ConclusionsThis study showed that the presence of aneurysm plays an important role in the remodelling of the carotid arteries. Also, it is understood that Murray’s laws are still valid for the detection of structural deterioration in carotid artery diseases. Hence, it is believed that these data can be used in artificial intelligence studies.

Retrospective Investigation Of The Relationship Between The Stylohyoid Ligament And Carotid Dissection

Purpose : Carotid dissection is the most important cause of ischemic stroke in young adults. Ischemic stroke rate up to 20% in people under 50 years. Recently, young patients under 50 years of age who were admitted to the emergency department with ischemic stroke complaints were diagnosed with carotid dissection. Methods : For this purpose, cranio-cervical CT angio images of patients admitted to our clinic with suspected carotid artery dissection and diagnosed as ICA dissection were retrospectively reviewed. the characteristics of the patients with ICA dissection and normal patients undergoing cranio-cervical CT angiography were investigated using 3D anatomical programs, specifically the course of the stylohyoid ligament, the distance between stylohyoid ligament and the carotid artery, and contact between stylohyoid ligament and the carotid artery. Sectra and AW Server 2 archives and XIO 4.80 radiotherapy planning programs were used for 3D analysis of the images. The data obtained from the analyzes were evaluated using the SPSS statistical program. Results : Descriptive statistics, Independent Samples T-Test, Pearson correlation analysis, multiple regression analysis, and graphical programs were used in statistical evaluations. According to Independent Samples T-Test results performed under SPSS, the distance between the ICA with stylohyoid ligament at 0.05 (sig.2-tailed) level (t = 5,950, sig = 0,000) and the difference between the age of the patients (t = 2,226, sig = 0,026) was significant. In addition, the axial (t = 2,938, sig = 0,005) and sagittal (t = 2,307, sig = 0,026) angles between the genders were different. In Pearson correlation analysis, styloid axial angles (r = -0.316, sig = 0.029), styloid sagittal angles (r = -0.333, sig = 0.020) and age of ICA dissection (r = -0.332, sig = 0.026) at 0,05 (2-tailed) level was found to be correlated. More importantly, in patients with ICA dissection, it was found that there was a strong correlation between stylohyoid ligament-carotid distance (r = -0.659, sig = 0.000) at the 0.01 (2-tailed) level. Conclusion : As a result, the closure of the stylohyoid ligament closer than 3.9 mm to the carotid for any reason increases the risk of dissection in young patients. It is thought that the results of this research will constitute a step for radiological artificial intelligence studies.

Feasibility study of iterative model reconstruction combined with low tube voltage, low iodine load, and low iodine delivery rate in craniocervical CT angiography

To investigate the feasibility of iterative model reconstruction (IMR) combined with low tube voltage, low iodine load, and low iodine deliver rate in craniocervical computed tomography angiography (CTA). Sixty patients were randomly divided into two groups (n=30 for each): group A: 120 kVp, 50 ml of iopromide at a flow rate of 5 ml/s; filtered back projection (FBP) reconstruction; group B: 80 kVp, 30 ml of iohexol at 4.5 ml/s; hybrid iterative reconstruction (HIR) for group B1 and IMR for group B2. CT attenuation values, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), subjective image quality, effective dose (ED), iodine load, and iodine delivery rate (IDR) were compared. CT attenuation values of the arteries were higher in groups B1 and B2 than group A. The SNR and CNR were higher, while image noise was lower, for group B2 compared with groups B1 and A. The best subjective image quality was obtained with group B2. ED, iodine load, and IDR reduction of 69.6%, 51.4%, 27%, respectively, was obtained in group B compared with group A. IMR combined with 80 kVp and 30 ml of iohexol at a flow rate of 4.5 ml/s for craniocervical CTA can reduce ED, iodine load, and IDR, while improving image quality.

A comparison of adaptive iterative dose reduction 3D and filtered back projection in craniocervical CT angiography

To compare the effects of exposure parameters on image quality and radiation dose for craniocervical computed tomography angiography (CTA) using adaptive iterative dose reduction in three dimensions (AIDR 3D) and filtered back projection (FBP) algorithms. One hundred and eighty patients were divided into three groups; group A (120kV, 300mA, FBP), group B (100kV, automatic mA, AIDR 3D) and group C (80kV, automatic mA, AIDR 3D). Image quality and radiation dose were evaluated for each group. For both cervical and intracranial vessels, CT attenuation, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were higher in the AIDR 3D groups. The difference in mean vascular noise was also statistically significant (p<0.001), with group B having the lowest value at 16.5±3.2 HU and group C having the highest at 19.1±2.9 HU. FBP reconstruction resulted in lower image-quality scores for the common carotid artery. Parenchymal image-quality scores also varied significantly different between groups with group C partially failing to meet the minimum standards for diagnostic use. For the middle cerebral artery, image-quality scores were significantly better in group A, although images from groups B and C also satisfied clinical diagnostic requirements. The image quality of the internal carotid artery was the best in group B. Image-quality scores between groups were not significantly different for the carotid sinus. Radiation doses in the groups using AIDR 3D were >70% lower than in the FBP group. AIDR 3D (100kV, automatic modulation) provides optimal image quality of vascular and parenchymal tissues at significantly lower radiation doses (mSV) than FBP in craniocervical CTA. For cases in which highly accurate parenchymal assessment is not required, the tube voltage can be lowered to 80kV to further decrease radiation dose.

Clinical analysis of carotid angioplasty stenting for high-grade extracranial carotid artery stenosis combined with severe tortuosity

To observe the feasibility and safety of carotid angioplasty stenting (CAS) for high-grade extracranial carotid artery stenosis combined with severe tortuosity. Twenty patients diagnosed with high-grade extracranial carotid artery stenosis combined with severe tortuosity by cerebral angiography, who were in hospital in neurology department of China-Janpan friendship from June 2011 to June 2014. Twelve of these patients were symptomatic. All cases weren't suit for or disagreed with carotid endarterectomy (CEA) to accept CAS. We retrospectively discussed the rates of technical success, the perioperative complications and clinical improvement. During the follow-up for 4 to 40 months we observed the events of cured carotid artery territory stroke and death, and record the plaque hyperplasia in stent, in-stent restenosis, stent deformation or fracture by color doppler ultrasonography or craniocervical CT angiography. (1) The results of operation: the rate of technical success was 19/20 and the rate of the distal protection device placement was 18/20. One stent and 2 distal protection device were difficult to pass the tortuous access vessels. The kinking was the most common in circuity classification of internal carotid artery. The stenosis was significantly improved after stenting, and the mean degree of stenosis was reduced from (82% ± 9%) before stenting to (7% ± 6%) after stenting. Although 5 patients were with perioperative complications, all symptoms disappeared within 1 weeks, and there was no stent related death and disability. There were 4 cases with vascular spasm, one of them was combined with carotid sinus reaction, and anther with transient ischemic attack (TIA) during operation. There was one with ipsilateral carotid territory minor stroke. (2) The results of prognosis and follow up: The clinical symptoms from 12 symptomatic patients were improved significantly on discharge, and the average NIHSS scores on admission were reduced from (4 ± 4) to (2 ± 2) on discharge. One patient experienced ipsilateral carotid territory minor stroke and another patient experienced ipsilateral carotid territory TIA during the follow-up for an average of 19 months, and there were 5 cases with mild plaque hyperplasia in stent and no in-stent restenosis, stent deformation or fracture. The severe tortuosity of extracranial carotid artery may affect the using of intervention materials and increase the complexity of CAS, but for the patients who disagree with CEA or were with the contraindications to CEA, CAS may be still a relatively safe, effective and alternative treatment.

Hybrid Iterative Reconstruction Algorithm Improves Image Quality and Helps to Decrease Radiation Dose in 256-Slides Craniocervical CTA

Purpose: The purpose of this study is to prospectively compare the image quality and radiation dose in two different 256- slice MDCT using Filter Back Projection and iDose4 (Hybrid iterative reconstruction) algorithm craniocervical CT angiography. Materials and methods: Thirty patients were randomly assigned into two groups (Group A and B), each comprising 15 patients. All patients underwent craniocervical CTA examination. Group A (10 men, 5 women; mean age 57.13 ± 11.27; age range 41-73 years) and Group B (9 men, 6 women; mean age 58.80 ± 12.55; age range 41-76 years) received different amount of X-ray tube potential and tube current and underwent on two different version of reconstruction algorithm. Then two blinded radiologist analyzed image quality of craniocervical CTA independently. They performed the subjective image quality and objective image quality assessment. The Effective Radiation Dose (ED) was calculated using CT dose volume Index (CTDIvol.), Dose-Length Product (DLP) and conversion coefficient for chest (conversion factor k=0.014 mSv mGy-1cm-1). We used chi-square test, and Maan-Whitney U test for non-parametric independent t test for subjective evaluation of image quality and to assess inter-observer reproducibility of the image quality by the subjective method between two observers, we used the interclass correlation test. Result: The quantitative image quality of iterative reconstruction algorithm was significant compared to FBP. The mean image noise in group B was 0.51 times lesser than group A (P-value <0.001).The mean image scores in both the groups by radiologist 1 and radiologist 2 was (3.65 ± 0.48 vs. 3.33 ± 0.63 respectively, p=0.002) and (3.73 ± 0.45 vs. 3.40 ± 0.69 respectively, p=0.002). The radiation dose was found to be reduced by 55% in group B compared to group A (P<0.0001) in craniocervical CTA. Conclusion: Hybrid Iterative Reconstruction (HIR) Algorithm significantly improves the image quality in craniocervical CT, as well as helps to lower the radiation dose while maintaining the image quality.

Hybrid Iterative Reconstruction Algorithm Improves Image Quality in Craniocervical CT Angiography

The purpose of this study was to evaluate the potential of a hybrid iterative reconstruction algorithm for improving image quality in craniocervical CT angiography (CTA) and to assess observer performance. Thirty patients (mean age, 58 years; range 16-80 years) underwent standard craniocervical CTA (volume CT dose index, 6.8 mGy, 2.8 mSv). Images were reconstructed using both filtered back projection (FBP) and a hybrid iterative reconstruction algorithm. Five neuroradiologists assessed general image quality and delineation of the vessel lumen in seven arterial segments using a 4-grade scale. Interobserver and intraobserver variability were determined. Mean attenuation and noise were measured and signal-to-noise and contrast-to-noise ratios calculated. Descriptive statistics are presented and data analyzed using linear mixed-effects models. In pooled data, image quality in iterative reconstruction was graded superior to FBP regarding all five quality criteria (p < 0.0001), with the greatest improvement observed in the vertebral arteries. Iterative reconstruction resulted in elimination of arterial segments graded poor. Interobserver percentage agreement was significantly better (p = 0.024) for iterative reconstruction (69%) than for FBP (66%) but worse than intraobserver percentage agreement (mean, 79%). Noise levels, signal-to-noise ratio, and contrast-to-noise ratio were significantly (p < 0.001) improved in iterative reconstruction at all measured levels. The iterative reconstruction algorithm significantly improves image quality in craniocervical CT, especially at the thoracic inlet. Despite careful study design, considerable interobserver and intraobserver variability was noted.

Magnetic Resonance Imaging of the Fetal Central Nervous System in Singapore

Fetal imaging has improved with the development of faster magnetic resonance imaging (MRI) sequences, obviating the requirement for sedation. It is useful in characterising abnormality of the central nervous system in fetuses with abnormal or equivocal antenatal ultrasound findings. We reviewed all cases of fetal brain and spine MRI performed in our institution. All cases of fetal central nervous system MRI imaging from May 2006 to December 2008 were retrospectively reviewed, including fetal MRI, postnatal MRI and autopsy findings. Thirty-one fetuses were imaged with MRI for evaluation of the central nervous system of which 3 were specifically for spinal evaluation. On fetal MRI, there were 11 normal fetuses (2 with minor ventricular asymmetry), 4 fetuses with minor ventriculomegaly and 16 fetuses with significant abnormalities. Twenty-three fetuses were delivered and 8 were terminated. Fifteen of 23 babies underwent postnatal imaging, 21 had clinical follow-up and 2 were lost to clinical follow-up. Of the 11 fetuses reported as normal on fetal MRI, 3 had additional postnatal findings. A fetus with a megacisterna magna on fetal MRI was diagnosed with a posterior fossa arachnoid cyst on postnatal MRI. One, who had fetal MRI to assess suspected absent inferior cerebellar vermis, had intracranial calcifications from rubella infection. One was diagnosed with cerebro-occular-facio-skeletal (COFS) syndrome postnatally, 1 was lost to follow-up and the rest were discharged well. Seven out of 16 fetuses with significantly abnormal fetal MRI findings had confirmation of the findings on postnatal imaging. Postnatal MRI detected 2 cases of polymicrogyria which were not seen on fetal MRI. Autopsy was available in 1 abortus confirming intrauterine diagnosis of Dandy Walker malformation. A myelomeningocele was clinically obvious in 1 abortus. Fetal MRI is a good method of assessing brain and spine abnormalities in utero. However, disorders of neuronal migration remain a challenging diagnostic problem in fetal imaging.

Dual Energy CT and Its Use in Neuroangiography

The dual energy CT (DECT) technology has been recently employed in the form of two X-ray sources of different energies to enhance the contrast between adjacent structures. Its use in the cardiac arena has been widely highlighted due to the higher temporal resolution. However, it may also be used in the craniocervical and peripheral vasculature for better differentiation between contrast-enhanced vascular lumina and calcified plaques, in the characterisation of ureteric stones, and in the evaluation of hepatic lesions. The objective of this paper is to revisit DECT physics, review the literature and discuss its use in CT neuroangiography with case illustrations from our institution, and impact on dose savings.

Comparison of Image Quality and Radiation Dose between Fixed Tube Current and Combined Automatic Tube Current Modulation in Craniocervical CT Angiography

The combined automatic tube current modulation (ATCM) technique adapts and modulates the x-ray tube current in the x-y-z axis according to the patient's individual anatomy. We compared image quality and radiation dose of the combined ATCM technique with those of a fixed tube current (FTC) technique in craniocervical CT angiography performed with a 64-section multidetector row CT (MDCT) system. A retrospective review of craniocervical CT angiograms (CTAs) by using combined ATCM (n = 25) and FTC techniques (n = 25) was performed. Other CTA parameters, such as kilovolt (peak), matrix size, FOV, section thickness, pitch, contrast agent, and contrast injection techniques, were held constant. We recorded objective image noise in the muscles at 2 anatomic levels: radiation exposure doses (CT dose index volume and dose-length product); and subjective image quality parameters, such as vascular delineation of various arterial vessels, visibility of small arterial detail, image artifacts, and certainty of diagnosis. The Mann-Whitney U test was used for statistical analysis. No significant difference was detected in subjective image quality parameters between the FTC and combined ATCM techniques. Most subjects in both study groups (49/50, 98%) had acceptable subjective artifacts. The objective image noise values at shoulder level did not show a significant difference, but the noise value at the upper neck was higher with the combined ATCM (P < .05) technique. Significant reduction in radiation dose (18% reduction) was noted with the combined ATCM technique (P < .05). The combined ATCM technique for craniocervical CTA performed at 64-section MDCT substantially reduced radiation exposure dose but maintained diagnostic image quality.

Whole-Body CT Trauma Imaging with Adapted and Optimized CT Angiography of the Craniocervical Vessels: Do We Need an Extra Screening Examination?

Blunt carotid and vertebral artery injury (BCVI) is rare but potentially devastating. The objective of our study was to prospectively evaluate the usefulness of a dedicated and optimized CT angiography (CTA) protocol of the craniocervical vessels as part of a whole-body CT work-up of patients with multiple trauma in a population of patients with blunt trauma. From February 2006 to July 2007, a total of 368 consecutive patients with trauma were evaluated. All examinations were performed on a 16-row multisection CT (MSCT) scanner. CTA was performed from the level of the T2 vertebra to the roof of the lateral ventricles with 40 mL of iodinated contrast agent. Images were reconstructed with use of the angiography and bone window settings to evaluate vessels and bones. Of all eligible patients imaged, 100 had injuries to the head and neck including 35 skull base fractures (9.5%), 24 maxillofacial (6.5%), and 11 cervical spine fractures (3%). CTA was diagnostic in all patients. BCVI was diagnosed in 6 cases (6 lesions of the internal carotid artery, 3 lesions of the vertebral artery); among them were 2 who did not meet the screening criteria. No patient with negative results on CTA subsequently had development of neurologic deficits suspicious for BCVI. This study confirms that optimized craniocervical CTA can be easily integrated into a whole-body CT protocol for patients with multiple trauma. No additional screening technique is necessary to identify clinically relevant vascular injuries. Earlier recognition enables earlier treatment and may decrease mortality and morbidity rates of these rare but potentially devastating injuries.