Notes on the RANZCR MRI Clinical Image Review Program
Part of the Adelaide MRI Website Collection
Prepared By Greg Brown
Updated Junne 28th 2001
General Information about MRI MRI Professional Societies


This summary should not be construed as a definitive statement of RANZCR or Royal Adelaide Hospital policy.
When preparing image for the Clinical Image Review you should consult the latest RANZCR documents.

Introduction

Under the draft  RANZCR  Accreditation Standards For Diagnostic And Interventional Radiology (Version 4 Draft 1 available from the web ) , each MRI unit must participate in the RANZCR’s MRI Clinical Image Review Program (CIRP).  In addition, each MRI unit must submit images of an approved phantom for review by RANZCR approved consultants, at intervals determined by the RANZCR. (clause T1.2.2)

The Clinical Image Review Program  is conducted on a small set of submitted images that are reviewed by an unspecified number of unnamed radiologists.  Reasonable steps are taken to ensure that the reviewing radiologists have no obvious clue which site they are reviewing.  Reviewers are to  assess images against an  unspecified set of objective criteria as well giving an overall impression of the images.   The site under review will receive "detailed feedback on  the objective criteria fro each examination".
Clearly the concepts of the CIRP and much of the original RANZCR MRI quality accreditation guidelines are drawn from similar  American  College of Radiologists documents. 


Image presentation

One sheet of film per required sequence, containing 15 – 20 images.
Images for each anatomical region must come from the same patient examination & should be acquired with normal imaging parameters.  The use of "extended acquisition periods will not be acceptable".  The documents don't' explain if this means the images should not contain pathology, or if the panel will judge if the sequence has been extended from normal practice in an attempt to misrepresent the site's standard clinical technique.

Technical parameters must be shown on the images, but patient identification and practice identification  must be removed.   It isn't clear if full sequence details should be supplied as well, or if the reviewer will try to determine all technical details from the available image annotation.
The required sequences are loosely defined (Axial Long TR Long TE).
As usual, spatial resolution is poorly handled. (FOV standard size to include all specified anatomy, minimum matrix specified, and in one instance a maximum slice thickness)  The requirements are not in any sense technically demanding, and do not represent more than a minimum acceptable standard.   I would expect most sites will submit images far exceeding the implied minimum requirements.
The minimum matrix required is specified a little unusually with the phase steps first.  I have used the more conventional method in this page. There is no mention of rectangular matrices so I assume they will accept a rectangular voxel.


Required Clinical Examinations & Sequences

Knee: Routine examination for internal derangement or meniscal injury

2 sequences.  One coronal and one sagittal.  One sequence with bright fluid. (Presumably the other has dark fluid)  Minimum Matrix 256 x 192.

Brain A: Routine Examination for suspected Multiple Sclerosis

Film 1: Axial .  Long TR Long TE  Minimum matrix 256 x 192
Film 2: Sagittal or Coronal FLAIR. Minimum matrix 256 x 192
OR
Film 2: Sagittal or Coronal Long TR Short TE Minimum matrix 256 x 192

Brain B: Evaluation of Circle of Willis for Stroke

MRA of Circle of Willis (The posterior fossa and neck is  not required.) Minimum matrix 256 x 128

Cervical Spine: Routine Examination for suspected radiculopathy

Thin section axial images from C4 to T1.  Dark or Bright fluid. Slice thickness 4 mm or less. Minimum matrix 256 x 128.

Lumbar Spine: Routine examination for sciatica

Film 1: Sagittal Long TR Long TE Minimum Matrix 256 x 192
Film 2: Axial Long TR Lng TE at least from L3 to S1 Minimum matrix 256 x 192

Discussion

The most obvious point is that the required images are technically very undemanding.   Its hard to imagine a scanner manufactured in the past 10 years that couldn't produce the required images with sequences under 5 minutes.
The other obvious point is that the objective criteria for assessment should be public.  I would hope they are a lot  better defined and more appropriate to modern MRI than the loose requirements recorded above.
The document should cite minimum spatial resolution in terms of slice thickness and in-plane resolution.  The use of inter slice interpolation (common in 3D MRA sequences ) should be mentioned as acceptable or not.  the current references to spatial resolution are way too open to interpretation., for example what FOV is sufficient to include the required anatomy of the axial lumbar spine?  120 mm to cover paravertebral structures, or 360 mm to include the flanks and avoid aliasing ?   With the specified minimum matrix there is  a 300% variation in inplane resolution which could yield a 900% variation in SNR (based on voxel volume) implying a theoretical 8400% variation in scan time.
ere is no consideration of the T2 induced blurring, presumably the assessors will eyeball inplane resolution and not rely on the indicated figures.

Filtering is not specifically banned, so some sites will submit images with significant digital modification, reflecting their normal clinical practice.


Region specific comments

Knee: Many sites use a group of sequences designed to detect mensical injury , bone bruise, cartilaginous damage.   The  only bright fluid sequence apart from the fat suppressed T2 would be in the axial plane to assess patellar cartilage. Would the panel accept STIR as a bright fluid sequence ? If so what about a  photonegative fat suppressed SE T1 sequence?

Brain A Long TE Long TE. Does the panel have guidelines here.  The appearance of a 2500/90 T2 TSE is quite different to a 4500/120.
The weighting available within the requirement of a long TR and short TE will have very variable appearances from real PD (2500/17) with CSF isointense or darker than white matter, through to moderate T2 weight (4500/30) where the CSF will be bright.  The echo spacing and ETL will also affect quality here.

Brain MRA: The specifications here are so loose as to be ridiculous.  IMHO anyone producing MRA at 250 FOV  256 x 128 matrix should be ashamed.  The slice thickness and TE are also significant issues here, and there is no indication of what projections should be provided, or if base images are to be supplied.  MRA images on a 20 format is quite inappropriate.

Cervical Spine: "dark or bright CSF" What a cop out. A dark CSF image for radiculopathy could be a T1 or a T2 TSE with poor CSF signal control.  How about asking for one of each ? The minimum  matrix of 256 x 128 is really not appropriate any more unless the FOV is unusually small.

Lumbar Spine: OK, the CIRP asks for T2 axial and sagittal even though the fast T1 images are the most taxing given contrast, resolution and SAR issues.


What's Next ?

In the near future I hope to publish our submitted images and sequences, along with a set of images on the same subjects that would meet the minimum requirements of the CIR documents.
I'll try to get more information on the objective criteria.
Please contact me with your experience, details of feedback etc., and we should be able to compile a site that will assist those undergoing review and highlight points that the RANZCR can consider to enhance the role of this review method.