The Spiral MRI Study

Primary outcomes

1. Image quality - decreasing scan time

   Time frame: 60 minutes

   Participants will be scanned using 2 versions (standard and spiral) of 6 sequences (12 scans total). For each sequence pair, scan time will be sped up. Image quality will be compared between the 2 versions.

2. Image quality - tau

   Time frame: 60 minutes

   Measuring whether image quality is sufficient for routine diagnostic interpretation - specifically robustness to artifacts. The independent variable is a scanning parameter called tau, which researchers want to be long (because it makes the total scan time shorter). Researchers will compare the value of tau between SOC imaging and spiral. They will use a 5-point Likert scale to compare, where 1= undiagnostic (unacceptable), 2 = spiral scans slightly worse than SOC but acceptable, 3= spiral scans same as SOC (acceptable), 4= spiral scans slightly better than SOC (acceptable), 5=spiral scans much better than SOC (acceptable).

3. Image quality - consistent scan time

   Time frame: 60 minutes

   Participants will be scanned using 2 versions (standard and designed) of 6 sequences (12 scans total). Scan time will remain the same for each pair. Radiologists will compare each pair for differences in image quality using a 5-point Likert scale where 1= A much worse than B, 2=A slightly worse than B, 3=A comparable to B, 4=A slightly better than B, 5=A much better than B. A=new spiral scans and B=SOC scans.

4. Signal to Noise Ratio (SNR)

   Time frame: 60 minutes

   Measuring the SNR in images, by measuring the signal strength in the image and the calculated noise in those images and taking the ratio. Researchers will compare this SNR to that which their methods predicted.

5. Image quality - acoustic comfort

   Time frame: 60 minutes

   Image quality will be compared between running at full strength, which is noisy, and running at reduced strength, which should be quieter. A 5-point Likert scale will be used, where 1= A much worse than B, 2=A slightly worse than B, 3=A comparable to B, 4=A slightly better than B, 5=A much better than B. A=spiral scans with full gradient strength and B=spiral scans with reduced gradient strength (that should be quieter).

6. Acoustic noise

   Time frame: 60 minutes

   Scans will be compared between running at full strength and running at reduced strength. Participants will rate the acoustic noise using a 5-point Likert scale, where 1= A much louder than B, 2=A slightly louder than B, 3=A comparable to B, 4=A slightly quieter than B, 5=A much quieter than B. A=spiral scans with full gradient strength and B=spiral scans with reduced gradient strength.

7. Difference in Image quality

   Time frame: 60 minutes

   Based on the results of the other 5 outcome measures, specifically whether scan time impacts image quality, the desired time will be used and scans will be compared between SOC and their method. Image quality will be measured using a 5-point Likert scale, where 1= A much worse than B, 2=A slightly worse than B, 3=A comparable to B, 4=A slightly better than B, 5=A much better than B. A=new spiral scans and B=SOC scans.