EVALUATION OF IMAGE QUALITY AND ACQUISITION TIME IN ADULT BRAIN MAGNETIC RESONANCE IMAGING USING 1.5 TESLA: A SINGLE CENTRE STUDY

Abstract

Context

Brain Magnetic Resonance Imaging (MRI) involves multiple sequences and relatively long acquisition times. These factors can affect image quality and present challenges that necessitate continuous evaluation and optimisation to ensure diagnostic efficiency.

Aim

To assess the image quality and average acquisition time of adult brain MRI sequences on a 1.5T scanner.

Methods

This prospective study evaluated adult brain MRI images of consenting patients at a local MRI center in Nigeria.
The assessment focused on the following axial sequences:

• T1-weighted (T1W)

• T2-weighted (T2W)

• Fluid Attenuation Inversion Recovery (FLAIR)

Image Quality Evaluation:

• Quantitative:

  • Signal-to-noise ratio (SNR)

  • Contrast-to-noise ratio (CNR)

• Qualitative:

  • Visual Grading Analysis (VGA) performed by four observers with over 5 years of experience

The acquisition time for each sequence was recorded. Data were analyzed using VGA and SPSS version 25.

Results

A total of 100 adult brain MRI examinations were analyzed.

Quantitative Findings

• T1W demonstrated the highest SNR for:

  • Grey matter: 51.58

  • White matter: 40.16

• T2W produced the highest CNR: 9.23

• FLAIR displayed the lowest SNR and CNR among the evaluated sequences.

Qualitative Findings

• T2W achieved the highest VGA score: 4.75

• FLAIR was rated lowest in qualitative image quality.

Acquisition Time

• T1W had the longest scan time: 5 minutes 38 seconds

• T2W had the shortest acquisition time: 2 minutes 43 seconds

Conclusion

T2-weighted sequences demonstrated superior contrast-to-noise ratio and visual grading scores compared to T1W and FLAIR, suggesting better overall diagnostic image quality. While T1W achieved the highest SNR, its relatively long acquisition time highlights the need for optimisation. FLAIR performed poorest in both qualitative and quantitative parameters, indicating an area for potential protocol improvement.