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Published on: July 28, 2013
Preoperative Grading of Astrocytic Supratentorial Brain Tumors with Diffusion-Weighted Magnetic Resonance Imaging and
Mahsa Raisi-Nafchi1, Fariborz Faeghi1, Alireza Zali2
1Department of Radiology Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Background:
Diffusion-weighted imaging (DWI) is a form of magnetic resonance imaging (MRI) based on measuring the random Brownian motion of water molecules within the biological tissues and is particularly useful in tumor characterization.
Objectives:
The purpose of this study was to evaluate the diagnostic value of DW MRI and the apparent diffusion coefficient (ADC) for preoperative grading of astrocytic supratentorial brain tumors.
Patients And Methods:
Twenty-three patients (14 females, 9 males, mean age 43 years) with astrocytic supratentorial brain tumors underwent preoperative conventional MR imaging and DW MRI. The minimum, maximum and mean ADC values and the minimum, maximum and mean DWI signal intensities of each tumor were taken by placing several regions of interest in the tumor on DWI images and ADC maps. To assess the relationship between these values and the tumor grade, we used the Mann-Whitney U test and the Spearman correlation. Receiver operating characteristic (ROC) analysis was used to determine the cutoff value of the minimum, maximum and mean ADC values and the minimum, maximum and mean DWI signal intensities that had the best composition of sensitivity and specificity for differentiating low-grade and high-grade astrocytic brain tumors.
Results:
According to the pathology reports, 10 patients had low-grade astrocytomas (grades I, II) and 13 patients had high-grade astrocytomas (grades III, IV). The minimum ADC value showed a significantly inverse correlation with astrocytic tumor grade (P = 0.006). The correlation between the maximum ADC value and the maximum DWI signal intensity with tumor grade was direct (P = 0.013, P = 0.035). According to the ROC analysis, the cutoff values of 0.843 × 10-3 mm2/s, 2.117 × 10-3 mm2/s and 165.2 for the minimum ADC, maximum ADC and maximum DWI respectively, obtained the best combination of sensitivity and specificity for distinguishing low-grade and high-grade astrocytomas.
Conclusion:
Measuring minimum ADC, maximum ADC and maximum DWI signal intensity can provide valuable information for grading of astrocytic supratentorial brain tumors before surgery.
Insights
Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) measurements aid in preoperative grading of brain tumors. Minimum ADC, maximum ADC, and maximum DWI signal intensity effectively differentiate low-grade from high-grade astrocytomas.
Area of Science:
- Neuroradiology
- Oncology
- Medical Imaging
Background:
- Diffusion-weighted imaging (DWI) is a magnetic resonance imaging (MRI) technique that measures water molecule diffusion in tissues.
- DWI is valuable for characterizing brain tumors, including astrocytomas.
Purpose of the Study:
- To assess the diagnostic utility of DWI and apparent diffusion coefficient (ADC) for preoperative grading of supratentorial astrocytic brain tumors.
- To differentiate between low-grade and high-grade astrocytomas using quantitative MRI parameters.
Main Methods:
- Twenty-three patients with astrocytic supratentorial brain tumors underwent conventional MRI and DWI.
- Minimum, maximum, and mean ADC values and DWI signal intensities were measured.
- Statistical analyses, including Mann-Whitney U test, Spearman correlation, and ROC analysis, were employed.
Main Results:
- A significant inverse correlation was found between minimum ADC and tumor grade (P=0.006).
- Maximum ADC and maximum DWI signal intensity showed a direct correlation with tumor grade (P=0.013, P=0.035).
- ROC analysis identified optimal cutoff values for minimum ADC (0.843 × 10⁻³ mm²/s), maximum ADC (2.117 × 10⁻³ mm²/s), and maximum DWI (165.2) for distinguishing tumor grades.
Conclusions:
- Minimum ADC, maximum ADC, and maximum DWI signal intensity provide valuable preoperative grading information for astrocytic brain tumors.
- These quantitative DWI parameters can assist in surgical planning and patient management.
