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Computerized Tomography (CT) - C2.3

Definition: The process by which a thin beam of x-rays is passed through a patient and the numberof x-rays transmitted to the other side is measured with a detector.  The amount of x-ray transmission is determined by the combined attenuating properties of the tissues through which the x-rays pass.

Issue statement: The preponderance of medical literature suggests approximately 25% of CT reports may be false positive and/or reveal asymptomatic pathology which may adversely affect adjudication and future management of claims.  Reports must be interpreted by Medical Advisors in combination with reported clinical findings before opinion is given on the cause/effect relationship of the injury sustained to the pathology being reported radiologically.

Computed tomography is a valuable diagnostic tool in the diagnosis of musculoskeletal disease/injury.  Cross sectional display, excellent contrast resolution and the ability to allow the measurement of specific attenuation values are important characteristics of CT that underscore its potential to delineate and define soft tissue and bone alterations that may be undetectable with conventional radiography.   Reformation of transaxial images in the coronal or saggital planes and three dimensional analysis of image data is a significant advantage of CT

WCB-Alberta position

Payment for CT scanning should only be approved when significant objective medical findings are reported and a scan is required in the investigation of work related injury/illness.

Indications

Are similar to the indications for MRI scanning and the literature indicates the decision to use MRI scanning over CT scanning or vice versa may be controversial in some areas.

See the attached copy of the guidelines for choosing the most clinically effective and economic test (from the MR Centre, Edmonton).

Work relationship criteria

The region to be examined must include the region of injury accepted by the WCB. 

Clinical criteria for acceptance of responsibility

A report from a consultant documenting significant objective clinical findings and requesting the need for CT scanning.

1. Preliminary radiographs of the area of the body to be examined are required.
2. Intravenous, intraspinal or intradiscal administration of radiopaque contrast material or intra-arterial administration of radiopaque contrast material or air, to be designated by the referring consultant on the requisition for the scan.

WCB-Alberta requirements for arranging expedited examinations

• the examination report of the consultant making the request
• a requisition completed by the attending consultant, independent medical examiner, ROHAC consultant or Unit Medical Advisor
• an up-to-date C031 defining responsibilities accepted under the claim
• reports of all previous x-ray examinations should be on file
• the first page of the C060 (Worker's Report of Accident)

Criteria for denial of responsibility

• objective findings recorded by the family physician/consultant are absent or very marginal
• where it appears the examination is being requested entirely at the request of the claimant without documented medical need
• where it appears the family physician/consultant is requesting examination on a medical-legal basis to rule out pathology rather than to confirm objective clinical findings
• pregnancy.

Authorization

• combined responsibility of the Case Manager and Unit Medical Advisor
• in the absence of clinical criteria an "administrative CT" scan may be requested by the Case Manager. Under these circumstances, the Unit Medical Advisor should state "administrative authorization" within the signature and date stamp.
• if resolution can not be reached by the Case Manager and Unit Medical Advisor as to the need for the scan, requests will be reviewed by the Chief Medical Advisor/designate

 

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