Main Logo
Logo

Society for Pediatric Radiology – Poster Archive

  284
  0
  0
 
 


Final ID: Paper #: 139

Dose Reduction in PET/MRI in Young Pediatric Patients Under 5 years of Age

Purpose or Case Report: We aim to evaluate qualitative and quantitative image quality of low-dose PET-MRI in young patients.
Methods & Materials: 25 PET/MRI scans from 14 patients under the age of 5 years were analyzed. Mean age was 2.78 years. Imaging protocol included 4 minute PET acquisition per bed position with a mean of 4.1 MBq/kg activity of FDG. Simulated half-dose images were created by removing events from the PET file list. In addition to ordered subset expectation maximization (OSEM) reconstructions, PET data was reconstructed with Bayesian penalized likelihood reconstruction (Q.Clear, β = 350) for full and half-dose images.

MIP images from 4 reconstructions were viewed and rated by 2 radiologists based on image quality, noise, and sharpness on a 5 point Likert scale and artifacts on a 3-point Likert scale. Likert scale data was analyzed with Kruskall-Wallis test. Post-hoc pairwise analysis with Dunn test was performed with statistically significant differences (p<0.05). Weighted Cohen's kappa was calculated for interobserver agreement.

SUV analysis included the SUVmax, SUVavg, signal-to-noise (SNR) for liver, and contrast-to-noise (CNR) for lesions. SUVs were analyzed by Friedman’s test and post-hoc analysis with Nemenyi test.
Results: Likert data showed no statistical difference for image quality (chi2 = 5.1394, p= 0.16), sharpness (chi2 = 2.81, p = 0.24) Kruskal-Wallis test showed a significant difference for noise (chi2 = 20.187, df = 3, p = 0.0001). Post-hoc Dunn test showed half-dose scans were subjectively noisier than the full-dose scans. The Q.clear did not subjectively decrease noise when compared to the OSEM reconstructions. No artifacts were detected. Moderate agreement was shown (Κ= 0.411).

Liver SUVmax was higher in the half-dose scans (p from 4.9 x10-14 to 1.9 x10-5). However, liver SUVavg showed a statistically significant difference in only the half-dose OSEM vs. full-dose Q.Clear with bias of only 10%(p = 1.6 x10-5). Liver SNR decreased with half-dose and Q.Clear (p-value from 3.8 x10-14 to 0.024). Lesion SUVavg and SUVmax were significantly increased in the Q.Clear than the OSEM (p-value ranging 1.5 x 10-7 to 0.007) in both dose reconstructions. CNR was decreased in the half-dose (p from 6.1 x 10-5 to 0.006) and did not improve with Q.Clear (p from 0.65 to 0.91).


Conclusions: Simulated half-dose show qualitatively diagnostic but nosier images. Quantitatively, Q.Clear did not improve SNR or CNR. Future directions could explore optimization of Q.Clear’s β value.
  • Davis, James  ( Children's Hospital of Philadelphia , Philadelphia , Pennsylvania , United States )
  • Servaes, Sabah  ( Children's Hospital of Philadelphia , Philadelphia , Pennsylvania , United States )
  • Nevo, Elad  ( Children's Hospital of Philadelphia , Philadelphia , Pennsylvania , United States )
  • States, Lisa  ( Children's Hospital of Philadelphia , Philadelphia , Pennsylvania , United States )
Session Info:

Scientific Session V-C: Info/Nuclear/IR/ALARA

Nuclear Imaging/Oncology

SPR Scientific Papers

Due to circumstances surrounding the coronavirus pandemic, this final ePoster exhibit was not submitted.
You have to be authorized to contact abstract author. Please, Login or Signup.

Please note that this is a separate login, not connected with your credentials used for the SPR main website.

Not Available

Comments

We encourage you to join the discussion by posting your comments and questions below.

Presenters will be notified of your post so that they can respond as appropriate.

This discussion platform is provided to foster engagement, and stimulate conversation and knowledge sharing.

Please click here to review the full terms and conditions for engaging in the discussion, including refraining from product promotion and non-constructive feedback.

 

You have to be authorized to post a comment. Please, Login or Signup.

Please note that this is a separate login, not connected with your credentials used for the SPR main website.


   Rate this abstract  (Maximum characters: 500)