Overview of CT Selection for VirtuOst. Typically, the CT scan that is utilized for VirtuOst has been taken already for some other medical reasons and is being re-purposed for BCT. If no suitable previously-taken CT scan is available, a new CT scan can be taken specifically for the purposes of BCT. See the table below for a complete list of what types of clinical CT scans can be utilized for VirtuOst. In addition, the following conditions apply:
Scan Coverage. For BCT, most pelvic, abdomen, spine, chest, low-dose lung, and whole-body PET/CT scans can be analyzed if they adequately cover one proximal femur (lesser trochanter and above) or one vertebral body from T12–L3. For VFA, most abdomen, spine, chest, low-dose lung, and whole-body PET/CT scans can be analyzed; the test is performed on all complete vertebral levels between L4 and T4 that are visible in the scan. Neither BCT nor VFA can be applied to the cervical spine.
Slice Thickness and Intravenous Contrast. For BCT at the spine, the CT scan’s slice thickness cannot exceed 3.0 mm and the CT scan cannot be enhanced with intravenous contrast. For BCT at the hip, the CT scan’s slice thickness cannot exceed 5.0 mm and there is no restriction on intravenous contrast. For VFA, the CT scan’s slice thickness cannot exceed 3.0 mm and there is no restriction on intravenous contrast.
CT Scan Requirements
| Parameter | Requirement |
|---|---|
| Tube Voltage | 100–140 kVp |
| Display Field of View (DFOV) | The bone of interest must not be cut off in the FOV |
| Reconstruction Kernel | Soft to standard reconstruction kernel (“sharp” or “bone” kernels are not suitable for BCT due to possible distortion of the attenuation data) |
| Hip-Specific: | |
| Coverage | Just above the top of the femoral head to below the femoral neck, just below the lesser trochanter being preferable |
| IV Contrast | With or without |
| Slice Thickness | ≤ 5 mm |
| Spine-Specific: | |
| Coverage | Complete coverage of one vertebral body from T12–L3 |
| IV Contrast | Without (BCT is not performed at the spine for scans with IV contrast) |
| Slice Thickness | ≤ 3 mm |
Eligible CT Scans for VirtuOst
| Scan Description‡ | CPT Code | Hip BCT | Spine BCT* | VFA |
|---|---|---|---|---|
| Chest w/o | 71250 | X† | X | |
| Chest with & w/o | 71270 | X† | X | |
| Low-dose Lung Cancer Screen | 71271 | X† | X | |
| Thoracic w/o | 72128 | X | X | |
| Thoracic with & w/o | 72130 | X | X | |
| Lumbar w/o | 72131 | X | X | |
| Lumbar with & w/o | 72133 | X | X | |
| Pelvis w/o | 72192 | X | ||
| Pelvis with | 72193 | X | ||
| Pelvis with & w/o | 72194 | X | ||
| Abdomen w/o | 74150 | X | X | |
| Abdomen with & w/o | 74170 | X | X | |
| CTA abdomen/pelvis with & w/o | 74174 | X | X†† | X |
| CTA abdomen with & w/o | 74175 | X†† | X | |
| Abdomen/pelvis w/o | 74176 | X | X | X |
| Abdomen/pelvis with | 74177 | X | X | |
| Abdomen/pelvis with & w/o | 74178 | X | X | X |
| CT colonography DX | 74261 | X | X | X |
| CT colonography DX w/dye | 74262 | X | X | X |
| CT colonography screening | 74263 | X | X | X |
| PET-CT, limited§ | 78814 | X | X† | X |
| PET-CT, skull base to mid-thigh§ | 78815 | X | X | X |
| PET-CT, whole body§ | 78816 | X | X | X |
| CT scan taken for BCT | 0558T | X | X | X |
† Check protocol and/or scan for adequate anatomic coverage
†† For CTA scans, BCT Spine can only be performed if an image w/o contrast is also acquired
§ For PET-CT, the non-contrast CT taken for anatomical localization is used for VirtuOst
‡ with, with & w/o, and w/o refer to whether or not intravenous contrast was administered; no IV contrast is allowed for Spine BCT