Open Access
CC BY-NC-ND 4.0 · Arquivos Brasileiros de Neurocirurgia: Brazilian Neurosurgery 2025; 44(03): e182-e187
DOI: 10.1055/s-0045-1809962
Original Article

Comparative Efficacy of TOF MRA and CT Angiography in Cerebrovascular Disease Diagnostics

Eficácia comparativa da TOF MRA e da angiografia por tomografia computadorizada no diagnóstico de doenças cerebrovasculares

Autoren

  • Khoroushi Farzaneh

    1   Department of Radiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
  • Farrokh Seilanian Toosi

    1   Department of Radiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
  • Fathabadi Amirhossein

    2   Department of Medical Physics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
    3   Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran
  • Aminzadeh Behzad

    1   Department of Radiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
  • Jarrahi Lida

    4   Department of Community Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
  • Sheibak Narges

    3   Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran

Funding The author(s) received no financial support for the research.
 

Abstract

Objective

To compare the diagnostic value of 3D Time-of-Flight Magnetic Resonance Angiography (3D TOF MRA) with Computed Tomography Angiography (CTA) in assessing cerebrovascular disease (CVD).

Methods

A retrospective observational study included 205 adult patients who underwent both TOF MRA and CTA scans. Demographic data, clinical symptoms, and imaging findings were analyzed. Diagnostic parameters were calculated for TOF MRA using CTA as the reference standard.

Results

Among 205 patients (mean age: 60 ± 11.67 years), TOF MRA detected more vessel occlusions (45.9%) than CTA (39%). CTA, however, identified more aneurysms (2.9% versus 1.5%). TOF MRA showed a sensitivity of 88%, specificity of 76%, and overall diagnostic efficacy of 84%. A significant association between CVD changes detected by MRA and CTA was observed (p < 0.001).

Conclusions

TOF MRA demonstrated a higher detection rate for vessel occlusions but was less effective than CTA in detecting vessel stenosis and aneurysms. TOF MRA is safer for repeated use and in patients with renal insufficiency due to the absence of contrast agents and ionizing radiation. However, its lower spatial resolution may lead to misclassification.


Resumo

Objetivo

Comparar o valor diagnóstico da Angiografia por Ressonância Magnética com Técnica de Tempo de Voo 3D (3D TOF MRA) com a Angiografia por Tomografia Computadorizada (CTA) na avaliação de doenças cerebrovasculares (DCV).

Métodos

Um estudo observacional retrospectivo incluiu 205 pacientes adultos que realizaram exames de TOF MRA e CTA. Dados demográficos, sintomas clínicos e achados de imagem foram analisados. Os parâmetros diagnósticos foram calculados para TOF MRA usando CTA como padrão de referência.

Resultados

Entre os 205 pacientes (idade média: 60 ± 11,67 anos), a TOF MRA detectou mais oclusões vasculares (45,9%) do que a CTA (39%). No entanto, a CTA identificou mais aneurismas (2,9% contra 1,5%). A TOF MRA apresentou uma sensibilidade de 88%, especificidade de 76% e eficácia diagnóstica global de 84%. Observou-se uma associação significativa entre as alterações de DCV detectadas pela MRA e pela CTA (p < 0,001).

Conclusões

A TOF MRA demonstrou uma taxa de detecção superior para oclusões vasculares, mas foi menos eficaz que a CTA na detecção de estenoses vasculares e aneurismas. A TOF MRA é mais segura para uso repetido e para pacientes com insuficiência renal, devido à ausência de agentes de contraste e radiação ionizante. No entanto, sua menor resolução espacial pode levar a erros de classificação.


Introduction

Cerebrovascular disease (CVD) is a major public health concern globally, significantly contributing to morbidity and mortality.[1] CVD encompasses a range of conditions that affect the blood vessels and blood supply to the brain, leading to potentially severe outcomes such as stroke, transient ischemic attacks, and other neurologic impairments.[2] The World Health Organization reports that stroke, a primary manifestation of CVD, is the second leading cause of death and the third leading cause of disability worldwide.[1] [3] The burden of CVD is profound, with significant implications for healthcare systems, economies, and the quality of life of affected individuals and their families.[2]

Accurate and timely diagnosis is crucial for effective management of cerebrovascular disease. The utilization of advanced imaging techniques has revolutionized the diagnostic process by enabling the evaluation of cerebrovascular abnormalities.[4] Traditionally, Digital Subtraction Angiography (DSA) has been considered the gold standard for diagnosing cerebrovascular conditions due to its high spatial resolution and excellent visualization of the vascular anatomy.[5] DSA involves the injection of contrast material into the bloodstream and the acquisition of detailed images, which can highlight even small vascular anomalies with high precision. However, despite its diagnostic superiority, DSA is an invasive procedure associated with potential complications, including bleeding, infection, and adverse reactions to contrast agents.[6]

To mitigate the risks associated with DSA, non-invasive imaging modalities such as Computed Tomography Angiography (CTA), Contrast-Enhanced Magnetic Resonance Angiography (CE MRA), and Time-of-Flight Magnetic Resonance Angiography (TOF MRA) have been developed and widely adopted in clinical practice. Each of these modalities offers distinct advantages and limitations, influencing their use in different clinical scenarios.[7]

CTA has become a widely used and standard technique for evaluating cerebrovascular disease. CTA involves the use of a CT scanner and intravenous administration of iodinated contrast material to obtain detailed images of the cerebral vasculature.[8] One of the key advantages of CTA is its high spatial resolution, which enables the accurate detection of a wide range of cerebrovascular abnormalities, including stenosis, occlusions, aneurysms, and arteriovenous malformations.[9] [10]

However, CTA is not without its limitations. The use of ionizing radiation in CTA poses a risk, particularly with repeated exposures, which can be a concern for patients requiring multiple follow-up scans.[11] [12] Additionally, the administration of iodinated contrast agents can lead to adverse reactions, ranging from mild allergic responses to severe nephrotoxicity, especially in patients with pre-existing renal impairment.[13] These limitations necessitate the exploration of alternative imaging modalities that can provide comparable diagnostic accuracy without the associated risks.

TOF MRA has emerged as a promising non-invasive alternative to CTA.[14] TOF MRA leverages the inherent properties of blood flow and magnetic resonance imaging to generate detailed images of the cerebral vasculature without the need for contrast agents. This technique utilizes a strong magnetic field and radiofrequency pulses to excite hydrogen protons in the blood, producing high-contrast images of the blood vessels.[15] One of the primary advantages of TOF MRA is the elimination of contrast-related risks, making it a safer option for patients with renal insufficiency or contrast allergies.[16] Additionally, TOF MRA avoids exposure to ionizing radiation, making it suitable for repeated imaging and longitudinal follow-up studies.[15] [17]

Despite these advantages, the diagnostic proficiency of TOF MRA compared with CTA and CE MRA has been a subject of ongoing research and debate.[14] [15] [18] [19] [20] Some studies suggest that TOF MRA may have limitations in detecting small aneurysms and accurately characterizing complex vascular structures due to its lower spatial resolution and susceptibility to flow-related artifacts.[15] [21] Conversely, other studies highlight the capability of advanced TOF MRA techniques, such as 3-T contrast-enhanced MRA and 3D TOF MRA, to provide reliable and detailed evaluations of cerebrovascular conditions, comparable to those obtained with CTA.[17] [22]

The aim of this study is to investigate the diagnostic value of TOF MRA compared with CTA in the assessment of cerebrovascular disease. Through the analysis of essential diagnostic parameters, our objective is to assess the reliability of TOF MRA as a non-invasive substitute for CTA.


Methods

Study Design and Population

A retrospective observational study was conducted, to investigate patients with acute neurologic symptoms and evaluate cerebrovascular disease. The study received approval from the Ethics Committee of ……………REC.1402.146). The study population comprised 205 adult patients (mean age: 60 ± 11.67 years) who underwent both TOF MRA and CTA scans within seven days of each other during the same admission. Demographic parameters, including age and, gender, were collected for each patient. Clinical symptoms such as weakness in limbs, aphasia, loss of consciousness, loss of balance, vertigo, numbness, dysarthria, and difficulty in vision were assessed. Inclusion criteria involved patients above 18 years of age with available TOF MRA and CTA images, while severe artifacts hindering interpretation or incomplete imaging protocols were considered as exclusion criteria. The imaging data obtained from the hospital's Picture Archiving and Communicating System (PACS) underwent anonymization using unique codes. The analysis of the imaging data revealed different cerebrovascular conditions, including vessel stenosis, vessel occlusion, aneurysm, and arteriovenous malformation. It is important to note that although DSA is widely considered the traditional gold standard for cerebrovascular evaluation, its unavailability for the selected patients precluded its inclusion in the study.


Image Acquisition

CT Angiography

CTA imaging was performed using a 16-MDCT scanner (Neusoft, Neuviz 16) to acquire multidetector-row computed tomographic angiography (MDCTA) data. The scanning parameters included a voltage of 120 kV, automatic mA selection, a matrix size of 512 × 512, a pitch of 1.5, a rotation speed of 0.6 seconds, a detector collimation of 16 × 0.75 mm, and a field of view (FOV) of 199 mm. A total of 150 mL of contrast material (Visipaqu 320 mg/mL) was administered to each patient through a 20-gauge needle in the antecubital vein, at a flow rate of 4 mL/s. Scanning was initiated using a bolus-tracking technique, starting when the region of interest (ROI) in the common carotid artery reached 80 Hounsfield units (HU), with a 5-second delay.


Magnetic Resonance Angiography

MRA was conducted using a 1.5 T scanner (Magnetom Vision; Avanto; I-class). The acquisition parameters for the 3D Time-of-Flight (TOF) MRA sequence were set as follows: a repetition time/echo time (TR/TE) of 25 milliseconds/7 milliseconds, a flip angle of 25 degrees, and FOV of 180 mm for the read direction with a phase FOV of 100%. The slice thickness was 0.5 mm with a slice oversampling of 14.3%. The actual bandwidth was 100 Hz/pixel, resulting in a voxel size of 0.7 × 0.7 × 0.5 mm. The total acquisition time for the MR imaging scan was 4 minutes and 58 seconds.



Image Interpretation

Two radiologists, blinded to the patients' clinical information, independently performed the interpretation of the imaging datasets. Initially, the CTA images were evaluated, followed by a separate interpretation of the TOF MRA images. To minimize recall bias, the TOF MRA images were assessed at least four weeks after the initial CTA evaluation. In cases of uncertain or conflicting results, the radiologists collaborated to reach a consensus. CTA was considered the reference standard, given its established accuracy and extensive clinical usage for evaluating cerebrovascular disease.


Statistical Analysis

The collected data were organized and stored in a database for further analysis. The performance of TOF-MRA in detecting CVD was summarized based on sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), with CTA serving as the reference standard. All statistical analyses were performed using SPSS version 26. p < 0.05 was considered statistically significant.



Results

Patient Demographics

A total of 205 patients were included in the study (84 female, 41%). Among the patients, the highest number of participants fell between the age range of 61–70 years, comprising 33.6% of the total patients. In terms of clinical symptoms, the most prevalent symptom reported was weakness in limbs, affecting 59.5% of the individuals. This was followed by loss of balance, loss of consciousness, and dysarthria as the common symptoms, in descending order ([Table 1]).

Table 1

Participant characteristics

Demographic Data

Frequency (%)

Gender

 Male

121(59%)

 Female

84(41%)

Age

 ≤50 years

44(21.4%)

 51–60 years

57(28%)

 61–70 years

69(33.6%)

 > 70 years

35(17%)

Chief complaint

 Weakness in limbs

122(59.5%)

 Aphasia

73(35%)

 Loss of consciousness

45(21.9%)

 Loss of balance

35(17%)

 Vertigo

51(24.8%)

 Numbness

19(9%)

 Dysarthria

104(50%)

 Difficulty in vision

25(12.1%)

Clinical history

 Diabetes mellitus

71(34%)

 Hypertension

102(49.7%)

 CAD

28(13%)

 Cancer

6(3%)

 CVA

14(7%)

Abbreviations: CAD, Coronary artery disease; CVA, Cerebrovascular accident.



Imaging Findings

Based on the imaging results represented in [Table 2], it was observed that the prevalence of vessel occlusion was higher in the 3D TOF MRA group (45.9%) compared with the CTA group (39%). Conversely, CTA exhibited a higher detection rate for aneurysms with 2.9%, whereas 3D TOF MRA had a detection rate of 1.5%, respectively.

Table 2

Comparative imaging results of TOF MRA and CTA techniques

Finding

CTA

3D TOF MRA

Normal

64(31.2%)

66(32.2%)

Vessel stenosis

54(26.3%)

42(20.5%)

Vessel occlusion

80(39%)

94(45.9%)

Aneurysm

6(2.9%)

3(1.5%)

Arteriovenous malformation

1(0.5%)

0(0%)


Comparison of TOF MRA and CTA

Among 139 cases where TOF MRA detected CVD, 124 were confirmed by CTA. Conversely, 17 out of 66 cases that were negative on TOF MRA showed CVD on CTA. A significant association between CVD changes detected by MRA and CTA was observed ([Table 3]). To evaluate TOF MRA's diagnostic performance against CTA, various parameters were calculated. MRA showed a sensitivity of 88%, a specificity of 76%, and an overall diagnostic efficacy of 84%, demonstrating its strong capability in diagnosing cerebrovascular disease ([Table 4]).

Table 3

Comparison of MRA and CTA in detecting cardiovascular disease in participants

3D TOF MRA

CTA (Gold standard)

Total

p-value

Absent, n(%)

Present, n(%)

Present, n(%)

15(7%)

124(60%)

139(67%)

<0.001

Absent, n(%)

49(24%)

17(8%)

66(33%)

Total

64(32%)

141(68%)

205

Table 4

Performance metrics of the TOF MRA

Diagnostic parameter

value

95% CI

Sensitivity

88%

(83–92%)

Specificity

76%

(70–81%)

PPV

89%

(84–93%)

NPV

74%

(68–78%)

Diagnostic efficacy

84%

(78–88%)



Discussion

Cerebrovascular disease is a significant global health concern, and precise diagnosis is crucial for effective management. While CTA has been the standard imaging modality, TOF MRA offers non-invasive imaging without radiation exposure. This study was aimed to assess the diagnostic performance of TOF MRA compared with CTA in a clinical setting.

Our study included 205 patients (mean age: 60 ± 11.67 years) with a slight male predominance. Hypertension was the most prevalent risk factor in our cohort, emphasizing its well-established association with CVD. A related study by Kazumitsu Nawata[1] found that age significantly influences CVD risk, with individuals aged 70 having nearly double the risk compared with those aged 50. Furthermore, a history of heart disease more than doubles the risk. The study conducted by Antoine Raberin et al.[23] highlights the influence of sex on the development of adverse cardiovascular disease effects. It was observed that as individuals age, men tend to be more susceptible to CVD compared with females. This difference in risk can be attributed to the effects of testosterone in elderly males, which can increase the risk of CVD. In contrast, estrogen in females has a vasodilatory effect, which contributes to a lower risk of CVD. In this study, approximately half of the cases (49.7%) had high blood pressure, which is known to increase the chances of stroke, atrial fibrillation, heart attack, and the formation of clots in the left ventricle.[24] [25] Likewise, the study conducted by Huimin Fan et al. found that hypertension was an independent risk factor for silent cerebrovascular disease in young patients who had their first-ever stroke.[26]

The imaging results from our study revealed distinct patterns in the detection rates of various cerebrovascular conditions when comparing TOF MRA and CTA. TOF MRA identified a higher prevalence of vessel occlusion (45.9%) than CTA (39%). However, it is important to consider the potential for misclassification in detecting vessel stenosis. TOF MRA detected fewer stenosis cases compared with CTA (20.5% versus 26.3%), indicating a possible overestimation of stenosis as occlusions in MRA. This observation is in line with the findings of the study conducted by Yukunori Korogi et al.,[27] which emphasize the importance of interpreting source images rather than maximum intensity projection (MIP) images in MR angiography to reduce the overestimation of stenosis and improve the sensitivity for detecting significant stenosis. In contrast, previous studies[9] [14] found that CTA exhibited higher sensitivity and positive predictive value than TOF MRA for detecting intracranial stenosis and occlusion. These differences may arise from varying examination methods and post-processing techniques employed in different studies. M. Lell et al.[28] highlighted the influence of these factors on stenosis grading, noting that CTA and TOF MRA showed the highest concordance when evaluated using multiplanar reconstruction (MPR). These insights highlight the importance of considering methodological variations and the expertise of observers in interpreting imaging results, which significantly impact the diagnostic accuracy of each modality.

Furthermore, our study revealed that CTA exhibited a higher detection rate for aneurysms (2.9%) compared with MRA (1.5%). These findings align with previous studies, which have consistently demonstrated the superior ability of CTA to detect aneurysms compared with MRA.[29] [30] This advantage can be attributed to CTA's higher spatial resolution and enhanced contrast capabilities, allowing for better visualization of small vascular abnormalities like aneurysms.[8] [10] However, advancements in MRI technology have led to the development of 3-T contrast-enhanced and 3D TOF MRA, which have shown reliability in evaluating and characterizing intracranial aneurysms. Previous studies[31] [32] [33] have demonstrated that these advanced MRI techniques produce results comparable to those of CTA in detecting and assessing aneurysms. These findings suggest that with state-of-the-art MRI techniques, clinicians may have viable alternatives to CTA for the evaluation of intracranial aneurysms.

One of the key strengths of this study lies in the considerable sample size, which consisted of 205 patients. This large cohort enhances the study's statistical power and lends credibility to the findings. Nevertheless, it is crucial to acknowledge certain limitations. First, the absence of DSA as a reference standard comparative modality restricts the comprehensive assessment of diagnostic accuracy. Additionally, the study's single-center design may limit the generalizability of the results to broader populations. To overcome these limitations, future research endeavors should focus on incorporating multicenter studies with larger and more diverse cohorts. Furthermore, the inclusion of DSA in the evaluation of diagnostic modalities would provide a more comprehensive analysis.


Conclusion

In conclusion, this study found that TOF MRA had a higher detection rate for vessel occlusions, while CTA was more effective in detecting vessel stenosis and aneurysms. TOF MRA has the advantage of being safer for repeated use and in patients with renal insufficiency due to its lack of contrast agents and ionizing radiation. However, its lower spatial resolution compared with CTA may lead to misclassification issues.



Conflict of Interest

The authors report no conflict of interest.

Authors' Contributions

FK, FST, BA, NS, ZBK, LJ, AF: material preparation, data collection, and data analysis; AF, NS: writing — original draft. All authors contributed to the conception and design of the study, critical review of the manuscript, and final approval.



Address for correspondence

Sheibak Narges, MD
Student Research Committee, Mashhad University of Medical Sciences
Mashhad
Iran   

Publikationsverlauf

Eingereicht: 29. Oktober 2024

Angenommen: 22. Mai 2025

Artikel online veröffentlicht:
08. Oktober 2025

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