[Simple volumetry of ischemic cerebral infarction using computerized tomography. Interobserver and method comparison]

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Accurate brain infarct volume assessment is crucial for patient management.
• Traditional methods using rulers and calculators for infarct volumetry have limitations.

Purpose of the Study:

• To evaluate the reliability of simple ruler-and-calculator methods for brain infarct volume assessment compared to planimetry.
• To determine the accuracy and precision of different ellipsoid and cylinder volume calculation techniques.

Main Methods:

• Three methods (A: ellipsoid, B: cylinder, C: modified ellipsoid) were used to calculate infarct volumes from CT scans.
• Volumes were calculated by multiplying lesion diameters and slice thickness, summing sectional volumes.
• Planimetry on a workstation served as the reference standard; inter-observer agreement was assessed.

Main Results:

• Method A underestimated volumes by -25%, Method B overestimated by +12.5%, and Method C by +18.6% compared to planimetry.
• The 95% confidence interval for agreement varied widely, especially for smaller infarcts (< or = 50 ml), ranging from 60% to 150%.
• For larger infarcts, the 95% confidence interval was approximately +/- 26 ml.

Conclusions:

• Simple methods for brain infarct volume estimation using rulers and calculators demonstrate significant variability.
• These methods are only reliable for detecting substantial changes in infarct volume, greater than 26 ml.
• Planimetry is recommended for more accurate and reliable brain infarct volume quantification.