Table 3.
Clinical practice variation in use of diagnostic tests in the outpatient clinic
| Number of hospitals (number of academic hospitals) | Initial test(s) | Confirmatory test(s) | Compliance to guidelines regarding use of initial and confirmatory test? | Compliance to guidelines regarding criteria for use of a confirmatory test? |
|---|---|---|---|---|
| Dutch guidelines | DUS | CTA or MRA | If carotid stenosis is >70 % for women or 50–69 % for men | |
| 7 (2) | DUS | CTA | Yes | No |
| 2 (0) | DUS | TOF-MRA | Yes | Yes (one hospital) No (one hospital) |
| 1 (0) | DUS | CE-MRA | Yes | No |
| 1 (1) | DUS or CTA | DUS or CTAa | No | No |
| 1 (0) | DUS | DUS and CTAb | No | No |
| 1 (0) | DUS | None | No | No |
| 1 (1) | DUS and CE-MRA or DUS and CTAc | None | No | No |
| 1 (1) | CTA | None | No | No |
| 1 (1) | CE-MRA | DUS | No | No |
DUS duplex ultrasonography, CTA computed tomography angiography, MRA magnetic resonance angiography, CE-MRA contrast-enhanced-MRA, TOF-MRA time-of-flight-MRA
aIf a DUS is used as initial test, a CTA is used as confirmatory test. If a CTA is used as initial test, a DUS is used as confirmatory test
bDUS is used as confirmatory test, even if an initial DUS is performed. CTA is used when the results of the initial DUS and confirmatory DUS differ
cChoice of DUS and CE-MRA or DUS and CTA is based on logistical reasons