Measurement Accuracy

Introduction

Measurement values in Synapse PACS are dependent on the calibration information provided by the modality in the DICOM header. Medical images are susceptible to magnification errors caused by differing patient sizes and projection distances. If not corrected by the modality, these errors can affect the accuracy of the calibration information contained in the DICOM header of the image.

Accuracy

Accuracy also depends on the pixel spacing and slice interval values that are provided in the DICOM header for the data set. Because of this, ruler measurements should be used for reference only, until the accuracy of the DICOM header information can be verified or the image information has been calibrated.

Accuracy of measurements:

• Length: 99.7%
• Angle: 99.5%
• Circle: 99.7%
• 2D Area: 99.8%
• 2D Length: 99.9%
• 2D Volume MOD: 99.9%
  • 2D Area: 99.4%
  • 2D Length: 99.7%
• Doppler Slope: 99.9%
  • Velocity: 99.6%
• P1/2 Time: 99.3%
• Peak Velocity: 99.9%
  • Peak Gradient: 99.7%
• Time (Doppler): 99.9%
• VTI: 99.6%
  • Peak Velocity: 99.9%
  • Peak Gradient: 99.8%
  • Mean Velocity: 98.1%
  • Mean Gradient: 97.1%
• MM Time: 99.9%
• MM Length: 99.8%
• MM Slope: 99.9%

It is the user's responsibility to ensure measurement accuracy based on need. The above values do not account for human errors.