SpinozaWiki:Quality Control

Quality Control procedure

The Quality Control (QC) procedure at the Spinoza centre is composed of a weekly and monthly protocol consisting various tests and checks. The QC is usually performed by the scan-assistants of the Spinoza centre, supervised by Tinka and Steven. Below, both procedures are summarized.

Weekly quality control procedure

Scans:

- Philips Intelligent Quality Test (PIQT): quality check of spatial stability. - BOLD-fMRI (EPI) and DTI-test using the AGAR-phantom: quality check of temporal stability. - Spurious test: quality check of homogeneity of static magnetic field. - QPI: check for spikes.

Check scanner computer: - Virus scan (monthly) and updates (weekly)

Check stimulus-set up in scanner room: - Set-up projection screen, beamer, and projected image - Response boxes - GSR/Eyetracker batteries

Check stimulus-computer: - Virus scan and update - Windows updates - Volume settings, headphone sound quality, Presentation licence - Trigger counter (during EPI-scan of the AGAR phantom) to check whether pulses are sent to the stimulus computer.

Check, misc.: - Helium level - Temperature - Back-up ProefpersonenRegistratie and Quality Control log (excel-sheets) - Amount of screening-forms, information brochures, and "Toestemmingsverklaringen"

Check

Spikes

When recording data When recording data you can see whether any possible spikes were present by inspecting the qpi values. This is a propietary value generated during recordings reporting on the smoothness of k-space. You can inspect the qpi values that were present during your recording via the Logging Applications

Start --> MR Applications --> Logging Application

An asp page starts. Enter qpi in free text box and select proceed. Next you get a screen indicating the qpi recordings that were measured during the day. Find your date en moment of recording. The qpi values should, in principle be 0 or close to 0. Values below 20 indicate minor problems that do not interfere with data analysis or the visual inspection of data. Values above 200 are definatly problematic. Please report any value above 20 immediatly. All QPI values are also evaluated on a weekly basis during the quality control procedure.

Spurious test when installing new equipment or changing something in the MRI enviroment

When new epquipment is installed or something is changed in the MRI enviroment a spurious test should be performed. This can be done from service mode. !! Crucial, make sure the headcoil is not connected to the system

Enter service mode. Go, in the acquisition enviroment to: System --> Advanced Tools --> Scan Utilities. Select the Scan Utilities in the pane on the left hand side. Select 1 (enter service mode) Select 2 (Batch Interpreter) Select 15 (spurious_t30_180hz_qbc) Select proceed

The spurious test now starts and will last for approximatly 4 minutes. After this a new subject has been created in the exam list called 'spur T30 180Hz/px'. Select New exam and open the 'subject'. Use the + sign to inspect the four images that have been created. That should be nice and homogenous as in the figure below on the right hand side and not contain no lines as in the figure below on the left hand side.