> ## Documentation Index
> Fetch the complete documentation index at: https://docs.spine.altician.com/llms.txt
> Use this file to discover all available pages before exploring further.

# CT Scan Support

> Open and explore CT DICOM files alongside MRI — including bone mesh generation, metal detection, and display presets

## Overview

ALTICIAN Spine supports CT DICOM files using the same drag-and-drop workflow you already use for MRI. No additional setup is required.

## Opening CT Files

Drag your CT DICOM folder (or individual `.dcm` files) into the app window. The volume loads automatically and displays in the 3D viewer.

<Note>
  CT and MRI files use the same loading workflow. If you have both, load them separately and switch between sessions as needed.
</Note>

## Automatic Bone Mesh Generation

When a CT series is loaded, the app can generate a 3D mesh of bony structures automatically.

* A **threshold slider** in the right panel lets you adjust which density levels are included in the mesh.
* Raising the threshold shows only dense bone; lowering it includes surrounding tissue.
* The mesh updates in real time as you move the slider.

## Metal Detection

Implants, screws, and other metallic hardware are identified automatically and separated from the bone mesh.

| What you see                        | What it means                   |
| ----------------------------------- | ------------------------------- |
| Separate mesh layer labeled "Metal" | Hardware detected and isolated  |
| Amber highlight in the panel        | One or more metal objects found |

You can toggle metal visibility independently from the bone mesh using the layer controls in the right panel.

## Window / Level Presets

CT images are commonly viewed with specific brightness and contrast settings. Use the **Preset** dropdown in the toolbar to switch between standard display modes:

| Preset      | Best for                    |
| ----------- | --------------------------- |
| Bone        | Bony anatomy and hardware   |
| Soft Tissue | Muscles, discs, and nerves  |
| Lung        | Thoracic cavity and airways |
| Abdomen     | Abdominal organs            |

You can also fine-tune brightness and contrast manually using the W/L tool.

## Differences from MRI

| Feature                   | MRI                          | CT                                    |
| ------------------------- | ---------------------------- | ------------------------------------- |
| Bone mesh auto-generation | Via AI segmentation (Helper) | Automatic via threshold               |
| Metal detection           | Not available                | Automatic                             |
| Window presets            | MRI-specific                 | CT-standard (Bone, Soft Tissue, etc.) |
| Segmentation labels       | Vertebrae, discs, cord       | Bone, Metal                           |
| Color appearance          | Soft-tissue contrast         | High bone contrast                    |

<Warning>
  CT-based bone meshes are generated from density thresholds and may include or exclude structures depending on the threshold setting. Review the mesh carefully before relying on it for any assessment.
</Warning>