L1 ⚛ L1-058 ⊙ Testnet

MR Angiography (time-of-flight / phase-contrast)

Medical Imaging · Non-contrast vascular MRI

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⬇ L1-058.md

# ⚛ L1 Principle — MR Angiography (time-of-flight / phase-contrast) **ID:** `L1-058` · **Status:** ⊙ Testnet (genesis catalog) > **🌐 Domain:** Medical Imaging — *Non-contrast vascular MRI* > **🎯 Problem class:** linear inverse · **🧮 Solution space:** 3D vessel map > **📡 Carrier:** radio_wave · **🌫 Noise:** gaussian > **⚖ Difficulty (δ):** 3 · **⛓ Block:** 41553359 --- ## 🧠 1. Introduction **MR Angiography (time-of-flight / phase-contrast)** is a **linear inverse problem** whose unknown lives in **3D vessel map** space, within the **Non-contrast vascular MRI** sub-domain of **Medical Imaging**. Measurements consist of radio-frequency electromagnetic waves via a **mri fourier encoding** sensing mechanism. The forward operator applies, in order: Bloch-equation tip of the magnetisation vector; L · tof saturation operator; L · kspace readout operator; pixel-level spatial averaging on the detector. Observations are corrupted by additive Gaussian noise. Existence of the recovered 3D vessel map is guaranteed within the declared Omega bounds. Uniqueness holds on the measurement-supported subspace; out-of-support modes are controlled by the declared priors. Stability is moderately conditioned (kappa_eff ~= 13); inplane_saturation dominates the stability cliff; motion and the remaining mismatch parameters contribute higher-order bias terms. Additive gaussian thermal/electronic noise sets the irreducible data-fidelity floor, while mild Tikhonov or analytic inversion is sufficient at the nominal Omega point. ## ⚙ 2. Forward Model Physical chain: **x** → RF excitation pulse → L · tof saturation → L · kspace readout → Spatial integration → **y** (detector). ``` y = ∫_A dA `L.kspace_readout` `L.tof_saturation` B₁(t) x + n, n ~ 𝒩(0, σ²) ``` **Measurement DAG:** | Primitive | What it does | |---|---| | `L.rf_excitation` | Bloch-equation tip of the magnetisation vector | | `L.tof_saturation` | L · tof saturation operator | | `L.kspace_readout` | L · kspace readout operator | | `int.spatial` | Pixel-level spatial averaging on the detector | ## 🔬 3. Physics Fingerprint | Property | Value | |---|---| | Domain | Medical Imaging | | Sub domain | Non-contrast vascular MRI | | Carrier | radio_wave | | Problem class | linear_inverse | | Solution space | 3D_vessel_map | | Noise model | gaussian | | Integration axis | spatial | | Difficulty delta | 3 | | L dag | 3.4 | ## 📡 4. Measurement Model Existence of the recovered 3D vessel map is guaranteed within the declared Omega bounds. Uniqueness holds on the measurement-supported subspace; out-of-support modes are controlled by the declared priors. Stability is moderately conditioned (kappa_eff ~= 13); inplane_saturation dominates the stability cliff; motion and the remaining mismatch parameters contribute higher-order bias terms. Additive gaussian thermal/electronic noise sets the irreducible data-fidelity floor, while mild Tikhonov or analytic inversion is sufficient at the nominal Omega point. | Metric | Value | |---|---| | Metric | PSNR_dB | | Secondary | SSIM | ## 📏 5. Operating Range (Ω) **Center problem class:** `mra` · **Forward operator:** `mra_forward` **Center point:** | Parameter | Unit | Value | |---|---|---| | H | px | 256 | | W | px | 256 | | Z | — | 128 | | Te ms | ms | 6 | | Tr ms | ms | 25 | | Snr db | dB | 22 | | Motion | — | 0 | | Inplane saturation | — | 0 | | Turbulence dephasing | — | 0 | **Allowed bounds:** | Parameter | Unit | Range | |---|---|---| | H | px | 128 | | W | px | 128 | | Z | — | 32 – 512 | | Te ms | ms | 3 – 30 | | Tr ms | ms | 10 – 100 | | Snr db | dB | 0.0 – 35.0 | | Motion | — | 0.0 – 0.5 | | Pulsatility | — | 0.0 – 0.3 | | Inplane saturation | — | 0.0 – 0.5 | | Turbulence dephasing | — | 0.0 – 0.3 | ## 🎯 6. Tolerance (ε) **Center tolerance:** 22.0 | Metric | Range | |---|---| | Psnr db | 5.0 – 45.0 | ## ⚖ 7. Hardness Function Hardness scales as **`epsilon_fn`** on **PSNR_dB**, with κ = `260` and δ = `3`. ## 💾 8. Reference Dataset - **primary** · weight 1.0 · IPFS _(not pinned yet)_ ## 9. On-chain Registration - **Chain hash:** `0x66f3d02088dd5bd6ecfc0f711984a4bc08eef8f5ae08bd4108ec93e2a4b1df82` - **Chain tx hash:** `0x92c8b6af4099a0d3253629476b004ea5e35b7f4366649fc9a46e3f6039145ce8` - **Chain block:** `41553359` --- ## File Mapping This bundle consists of: `L1-058.md`, `L1-058.json`. | File | Role | How to regenerate | |------|------|-------------------| | `L1-058.md` | Source of truth — edit this | Human or LLM | | `L1-058.json` | Structured metadata for the registry | LLM regenerates from the sections above | **Prompt for your LLM after editing this Markdown:** > Read the attached Markdown. Regenerate the sibling `.json` so every field matches. > Preserve the schema documented in the rows above. > Output each file in its own fenced code block tagged with the filename. > Output only the JSON object. _This Markdown was auto-synthesized from the catalog row for `L1-058`._ _Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._

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Read the attached Markdown (L1-058.md).
Regenerate L1-058.json so every field matches the Markdown.
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L2-058-001 MR Angiography (time-of-flight / phase-contrast) Mismatch-Only Spec

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📋 JSON metadata

{
  "artifact_id": "L1-058",
  "chain_block": 41553359,
  "chain_hash": "0x66f3d02088dd5bd6ecfc0f711984a4bc08eef8f5ae08bd4108ec93e2a4b1df82",
  "chain_tx_hash": "0x92c8b6af4099a0d3253629476b004ea5e35b7f4366649fc9a46e3f6039145ce8",
  "domain": "Medical Imaging",
  "hardness_fn": {
    "delta": 3,
    "kappa": 260,
    "metric": "PSNR_dB",
    "type": "epsilon_fn"
  },
  "initiator_dataset": [
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      "license_hash": null,
      "name": "primary",
      "weight": 1.0
    }
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  "layer": "L1",
  "observable_profile": {
    "metric": "PSNR_dB",
    "regime": "Existence of the recovered 3D vessel map is guaranteed within the declared Omega bounds. Uniqueness holds on the measurement-supported subspace; out-of-support modes are controlled by the declared priors. Stability is moderately conditioned (kappa_eff ~= 13); inplane_saturation dominates the stability cliff; motion and the remaining mismatch parameters contribute higher-order bias terms. Additive gaussian thermal/electronic noise sets the irreducible data-fidelity floor, while mild Tikhonov or analytic inversion is sufficient at the nominal Omega point.",
    "secondary": "SSIM"
  },
  "physics_fingerprint": {
    "L_DAG": 3.4,
    "carrier": "radio_wave",
    "difficulty_delta": 3,
    "domain": "Medical Imaging",
    "integration_axis": "spatial",
    "noise_model": "gaussian",
    "primitives": [
      "L.rf_excitation",
      "L.tof_saturation",
      "L.kspace_readout",
      "int.spatial"
    ],
    "problem_class": "linear_inverse",
    "sensing_mechanism": "mri_fourier_encoding",
    "solution_space": "3D_vessel_map",
    "sub_domain": "Non-contrast vascular MRI",
    "title": "MR Angiography (time-of-flight / phase-contrast)"
  },
  "size_tiers": {
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    ],
    "allowed_omega_dimensions": [
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      "W",
      "Z",
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      "TE_ms",
      "SNR_dB",
      "inplane_saturation",
      "motion",
      "turbulence_dephasing",
      "inplane_saturation",
      "motion",
      "turbulence_dephasing",
      "pulsatility"
    ],
    "allowed_problem_classes": [
      "mra"
    ],
    "center_spec": {
      "epsilon_fn_center": "22.0",
      "forward_operator": "mra_forward",
      "input_format": "measurement_only",
      "omega": {
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        "SNR_dB": 22,
        "TE_ms": 6,
        "TR_ms": 25,
        "W": 256,
        "Z": 128,
        "inplane_saturation": 0.0,
        "motion": 0.0,
        "turbulence_dephasing": 0.0
      },
      "problem_class": "mra"
    },
    "epsilon_bounds": {
      "psnr_db": [
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        45.0
      ]
    },
    "omega_bounds": {
      "H": 128,
      "SNR_dB": [
        0.0,
        35.0
      ],
      "TE_ms": [
        3,
        30
      ],
      "TR_ms": [
        10,
        100
      ],
      "W": 128,
      "Z": [
        32,
        512
      ],
      "inplane_saturation": [
        0.0,
        0.5
      ],
      "motion": [
        0.0,
        0.5
      ],
      "pulsatility": [
        0.0,
        0.3
      ],
      "turbulence_dephasing": [
        0.0,
        0.3
      ]
    }
  },
  "staked_pwm": 0.0,
  "status": "testnet",
  "sub_domain": "Non-contrast vascular MRI",
  "title": "MR Angiography (time-of-flight / phase-contrast)"
}

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