i4h Catheter Navigation - Interactive Viewport

Purpose

Launch the interactive fluoroscopy viewport with real-time XPBD catheter physics, DSA, C-arm presets, and centerline-guided insertion. Requires a digital twin cache from [[i4h-catheter-navigation-digital-twin]].

Base Code

ROOT="${I4H_WORKFLOWS:-$(git rev-parse --show-toplevel 2>/dev/null)}"
if [ ! -d "$ROOT/workflows/catheter_navigation" ]; then
  ROOT="${I4H_WORKFLOWS:-$HOME/i4h-workflows}"
  [ -d "$ROOT/workflows/catheter_navigation" ] || git clone https://github.com/isaac-for-healthcare/i4h-workflows "$ROOT"
fi
export I4H_WORKFLOWS="$ROOT"; cd "$ROOT"

Basics

• Entry mode: ./i4h run catheter_navigation interactive_viewport (preferred)
• Requires display (X11); remote/VNC may need QT_QPA_PLATFORM=xcb.
• Recommended flags: --vessel-source real --insertion-axis centerline --dsa --key-hold-ttl 0.20

Run

Run the steps below in order. Each step is a separate bash call; variables persist in the local agent's tmux session.

Step 1 - resolve cache and run dir

REPO_ROOT="${I4H_WORKFLOWS:-$(git rev-parse --show-toplevel 2>/dev/null)}"; [ -d "$REPO_ROOT/workflows/catheter_navigation" ] || REPO_ROOT="$HOME/i4h-workflows"
WF_ROOT="${REPO_ROOT}/workflows/catheter_navigation"
RUN_DIR="${WF_ROOT}/runs/viewport_$(date +%Y%m%d_%H%M%S)"
mkdir -p "${RUN_DIR}/logs"
ln -sfn "${RUN_DIR}" "${WF_ROOT}/runs/.latest"

CACHE="${CACHE:-/tmp/ct_cache}"
if [ ! -f "${CACHE}/mu_volume.npy" ]; then
  echo "viewport: set CACHE to a digital-twin dir (missing mu_volume.npy). Run i4h-catheter-navigation-digital-twin first." >&2
  exit 1
fi

Step 2 - launch viewport

QT_QPA_PLATFORM="${QT_QPA_PLATFORM:-xcb}" \
"${REPO_ROOT}/i4h" run catheter_navigation interactive_viewport --local \
  --run-args="--ct-dir ${CACHE} --vessel-source real --insertion-axis centerline --det-size 1024 --pixel-spacing-mm 0.6 --dsa" \
  2>&1 | tee "${RUN_DIR}/logs/viewport.log"

Controls (summary)

Input	Action
W / S	Advance / retract catheter along centerline
A / D	Rotate catheter CCW / CW
F / C	Toggle vessel / centerline overlay
X	Toggle DSA contrast bolus
1-4	C-arm presets (AP, LAO-45, Lateral, RAO-30)
Space	Pause / resume
R	Reset catheter
Q / Esc	Quit

Full table: workflows/catheter_navigation/README.md.

Prerequisites

• [[i4h-catheter-navigation-setup]] and [[i4h-catheter-navigation-digital-twin]] completed.
• Display server (local X11 or remote desktop with keyboard focus).
• GPU with >= 8 GB VRAM (16 GB recommended).

Limitations

• Interactive GUI - not suitable for headless CI.
• Keyboard focus on remote desktops may require pointer over the fluoro window.

Troubleshooting

• Error: controls appear dead on remote X11 - Fix: QT_QPA_PLATFORM=xcb (Step 2 sets this by default).
• Error: missing cache - Fix: run [[i4h-catheter-navigation-digital-twin]].
• Error: Vulkan / slang init failure - Fix: verify GPU driver; try Docker without --local.

Final Response

Report CACHE used, note any display/input workarounds applied, and point to README controls if the user needs the full key map.