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Low Dose Head Computed Tomography Protocol for Evaluation of Non-traumatic Emergencies in Children...
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Transcript of Low Dose Head Computed Tomography Protocol for Evaluation of Non-traumatic Emergencies in Children...
Low Dose Head Computed Tomography Protocol for Evaluation of
Non-traumatic Emergencies in Children
Rishi Mhapsekar, MDMarilyn J. Siegel, MD
Robert McKinstry MD, PhD
Poster # EP-142
Disclosures
• Rishi Mhapsekar: Nothing to disclose
• Marilyn Siegel: Speaker for Siemens Healthcare
• Robert McKinstry: Nothing to disclose
Purpose
• The purpose of our study was to evaluate if an unenhanced low-dose head CT could consistently provide acceptable image quality and diagnostic information
Materials and Methods
• 584 pediatric head CT scans performed
between January 2014 and December 2014
were retrospectively reviewed
• 365 CT scans were performed using a full dose
protocol to assess for traumatic emergencies
and 219 head CT scans were performed using
low dose protocols to evaluate for non-
traumatic emergencies
Materials and Methods
• CT examinations were performed on a 64-slice SOMATOM Definition AS scanner (Siemens Healthcare, Forchheim, Germany) equipped with automated tube-current modulation (CARE Dose4D)
• Full dose scans used quality references of 330 mAs and fixed 120 kV
• Low dose scans used references of 150 mAs and fixed 100 kV
Analysis
• All CT scans were reviewed for patient age, CT Dose
Index Volume (CTDIvol) in mGy, Dose Length
Product (DLP) in mGy.cm, milliamperage (mAs) and
kilovoltage (kVp)
• Data was recorded from the patient dose record
shown at the CT console
• Results of full and low dose scans were analyzed using
Shapiro-Wilk W test and Wilcoxon rank sums test
Qualitative Analysis
• One reader graded image quality
• Diagnostic image quality was graded on a 3 point scale (1, poor and unacceptable; 2, good; 3, excellent)
• Diagnostic acceptability was based on visualization of the sharpness of ventricular outlines, tissue contrast, and shunts (when present)
• Diagnostic noise was graded on a 3 point scale (1, unacceptable; 2, present, but not affecting diagnosis; 3) absent)
Results
• Median patient ages for full and low dose head CT protocols were 8.0 and 6.0 years respectively (p > 0.05)
• Median CTDIvol for full and low dose CT protocols were 28.7 and 8.8 mGy respectively (p < 0.001) (69% difference)
Results
• Median DLP for full and low dose CT protocols were 496 and 146 mGy.cm respectively (p < 0.001) (71% difference)
• Median mAs for full and low dose CT protocols were 295 and 88 mAs respectively (p < 0.001) (70% difference)
ResultsParameter Low Dose
ProtocolFull Dose Protocol
% Change
Median mAs 88 295 70%
Median CTDI 28.7 8.8 69%
Median DLP 146 496 71%
Results
• Low dose pediatric head CTs were of diagnostic image quality - grade 2 or 3 (2, good; 3, excellent)
• Low dose CT noise was graded as 2 or 3 (2, present, but not affecting diagnosis; 3) absent)
Diagnostic Image Quality
Low Dose Full Dose
15 year old girl with headacheCTDI: 11.6; DLP: 164
Diagnostic quality, some noise
16 year old boy with traumaCTDI: 26.8 ; DLP: 582
Diagnostic quality, no noise
Conclusion
• Low dose head CT protocols in children using lower mAs and kV reduce CTDIvol, DLP, and mAs by approximately 70%
• Low-dose non-enhanced head CT provides diagnostically acceptable images in non-traumatic emergencies