Calculated Fields
In the Carotid worksheet, the following fields are calculated automatically. These calculated values automatically update when any of the source values are changed.
| Field | Source Values | Calculation Logic |
|---|---|---|
| ICA/CCA PSV Ratio | One ICA PSV and one CCA PSV per laterality. Select list indicates which value. | ICA PSV ÷ CCA PSV Note: Studycast uses ICA PSV and CCA PSV by default, but you can specify a different segment in to be used in your worksheet preferences. |
| ICA/CCA EDV Ratio | One ICA EDV and one CCA EDV per laterality. Select list indicates which value. | ICA EDV ÷ CCA EDV Note: Studycast uses ICA EDV and CCA EDV by default, but you can specify a different segment in to be used in your worksheet preferences. |
| Stent Ratio | Stent PSV values within same stent | PSV ÷ PSV of proximal segment |
| Endarterectomy Ratio | Endarterectomy PSV values within same Endarterectomy | PSV ÷ PSV of proximal segment |
Carotid Criteria
By default, the Carotid worksheet uses the Mayo Clinic criteria. However, you can choose to use a different set of criteria, such as those listed below, or you can define custom criteria.
To change the criteria in your worksheets, contact Studycast Support.
Mayo Clinic (Default Criteria)
Grant et al, RSNA, 2003. Gocke, MIIT, 2004
| Primary Parameters | Additional Parameters | |||
| Degree of Stenosis (%) | PSV (cm/s) | Visual Plaque Estimate (w/Doppler) (%) | ICA/CCA PSV Ratio | EDV (cm/s) |
| Normal | Normal IMT, No plaque | |||
| Minimal | Increased IMT>0.10 cm | <40 | ||
| 1-15% | <125 | Mild | <1.6 | <40 |
| 16-49% | <125 | Moderate | <1.8 | <40 |
| 50-69% | 125-230 | >=50% | 2.0-4.0 | 40-99 |
| >=70% | >=230 | >50% | >4.0 | 100-140 |
| 80-99% | >=230 | Marked lumen narrowing | >140 | |
| Near Occlusion | Low, undetectable | Marked lumen narrowing | ||
| Total Occlusion | Undetectable | No lumen, no flow | ||
Radiology Consensus
Consensus of Society of Radiologists in Ultrasound, 2003
| Primary Parameters | Additional Parameters | |||
| Degree of Stenosis (%) | PSV (cm/s) | Visual Plaque Estimate (w/Doppler) (%) | ICA/CCA PSV Ratio | EDV (cm/s) |
| Normal | <125 | No plaque | <2.0 | <40 |
| <50% | <125 | <50 | <2.0 | <40 |
| 50-69% | 125-230 | >=50 | 2.0-4.0 | 40-100 |
| >=70% | >230 | >=50 | >4.0 | >100 |
| Near Occlusion | High, low, or undetectable | Visible | Variable | Variable |
| Total Occlusion | Undetectable | Visible plaque, no detectable lumen | NA | NA |
Washington
University of Washington, 1987
| Primary Parameters | Additional Parameters | ||
| Degree of Stenosis (%) | PSV (cm/s) | Visual Plaque Estimate (w/Doppler) (%) | ICA/CCA PSV Ratio |
| Normal | Normal IMT, No plaque | <1.6 | |
| 1-15% | <125 | Increased IMT, mild plaque | <1.6 |
| 16-49% | <125 | Moderate plaque | 1.8-2.0 |
| 50-79% | 125-135 | >=50% lumen narrowing | 2.0-4.0 |
| 80-99% | >=135 | Marked lumen narrowing | >4.0 |
| Near Occlusion | Low, detectable | String sign | |
| Total Occlusion | Undetectable | No lumen, no flow | |