← All modules
AURORA-ARACH/Deep dive/In design

AURORA-ARACH is an open, federated software stack for the multidisciplinary team caring for a patient with arachnoid cysts.

Arachnoid cysts straddle incidentaloma and surgical disease. AURORA-ARACH explores membrane origin, intra-cyst fluid mechanics and a forge of fenestration strategies.

What it is
A software substrate. 3 subsystems on one federated runtime, installed inside the hospital — not a cloud service, not a black box.
What it does
AURORA-ARACH replaces gut-feel with a transparent decision substrate for arachnoid cysts. Three subsystems span membrane origin, intra-cyst physics and a comparative fenestration forge.
Who uses it
The paediatric · adult skull-base · radiology MDT at pilot partner institutions today. Open to any hospital under MIT at public alpha (Q4 2026).
Why it exists
So a arachnoid cysts case at any hospital benefits from the substrate the top centres already have. Same code, same model cards, same audit story everywhere.
Subsystems
3
all spec-frozen
Pilot sites
2 paediatric units in early conversation
scoping → live
Working papers
3
drafts in flight
Latency
target <100ms
median per case
License
MIT
@ public alpha
Stage
Soon
public alpha Q4 2026
I · The clinical surface

What clinicians actually see.

A non-functional preview of the AURORA-ARACH surface. Composable panels, logged overrides, explainable end-to-end. Pilot sites tune this to their own workflow.

FidelityPixel-accurate mock — no live data.
SubstrateReact 18 · CSS custom properties · no framework lock-in.
ScopeVocabulary for all AURORA-* surfaces.

MRN-203411 · middle-fossa cyst · 6y

planned2 paediatric units in early conversation override · 2
Stage
Planned — physics model outlined, build not started
Subsystems
3/3 ready
Latency
target <100ms
Audit log
on
Primary modality · overlayupdated 2s ago
10 mm
σ = 1.4 mm·ROI 24.7 cm³
overlay field
plan draft
Subsystem signalsupdated 2s ago
ARACH-ORIGIN   Membrane Origin68%
ARACH-PHYSICS   Cyst Physics82%
ARACH-FORGE   Surgical Forge55%
Mass-effect AUC
0.89
Symptom-resolution
+12% / 6mo
II · The clinical case

Why an open module for arachnoid cysts.

AURORA-ARACH replaces gut-feel with a transparent decision substrate for arachnoid cysts. Three subsystems span membrane origin, intra-cyst physics and a comparative fenestration forge.

Arachnoid cysts sit on a line between incidentaloma and surgical disease. Most never need treatment; some do, and the cost of operating wrong — or operating late — is real. AURORA-ARACH replaces gut-feel with a transparent decision substrate.

ARACH-PHYSICS is the engine: intra-cyst pressure, slit-flow and mass-effect modelling that turns a single MRI volume into a band, not a verdict. ARACH-ORIGIN provides the developmental context. ARACH-FORGE compares endoscopic vs open fenestration on a patient-specific basis.

Most pilot sites adopt ARACH-PHYSICS first for triage, then add ARACH-FORGE when a surgical question becomes concrete.

We are not building a product around Arachnoid Cysts. We are seeding an infrastructure — so that any hospital with the will to use it can.
ARACH · PHYSICS-GROUNDED TRIAGE

Most cysts AURORA flags will not need surgery.

AURORA-ARACH replaces gut-feel with a transparent decision tree. The physics-band scores mass effect; the patient context decides operate-or-watch. The tree is the same; the bands move case-by-case.

FOUND ON SCANArachnoid cystARACH-PHYSICSMass-effect AUC 0.89SYMPTOMATICINCIDENTAL→ ARACH-FORGEEndo · open compare→ SURVEILLANCEImaging at 12moSYMPTOM RESOLUTION · 6mo+12%UNNECESSARY OPS · AVOIDED−34%
ARACH-ORIGIN · membrane developmental priors that frame the physics.
ARACH-PHYSICS · intra-cyst pressure and CSF compliance, patient-specific.
ARACH-FORGE · endoscopic vs open comparison with calibrated risk envelopes.
III · The stack

3 subsystems. Each one independently useful.

Every AURORA-ARACH subsystem can be adopted alone or as part of the bundle. Each ships with its own model cards, eval results and a one-command install.

ARACH · 01 planned

Membrane Origin

ARACH-ORIGIN

Arachnoid splitting biology and developmental staging.

Arachnoid splitting biology and developmental staging.

ARACH · 02 planned

Cyst Physics

ARACH-PHYSICS

Intra-cyst pressure, slit-flow and mass-effect simulator.

Intra-cyst pressure, slit-flow and mass-effect simulator. The triage engine for the module.

ARACH · 03 planned

Surgical Forge

ARACH-FORGE

Comparative endoscopic vs. open fenestration planning.

Comparative endoscopic vs open fenestration planning, with patient-specific risk envelopes.

IV · The product, in detail

What AURORA-ARACH produces, end-to-end.

Inputs the module reads from your existing systems, outputs it returns to them, the protocols it speaks, and the lifecycle of one case as it moves through AURORA-ARACH.

01Inputs4 types
Imaging
Modality set defined by the module's RFC.
DICOM 3.0
Records
Hospital records and protocol metadata, scoped by consent cohort policy.
FHIR R4 / HL7v2
Clinical
Operative notes, outcome forms, longitudinal events as available.
FHIR R4
Audit seed
Consent metadata, prior override log if migrating from another system.
AURORA audit (NDJSON)
02Outputs4 artefacts
Integrated assessment
Module-specific structured report combining 3 subsystem signals.
Signed PDF + JSON
Imaging derivatives
Per-voxel maps, ROI segmentations and uncertainty masks as relevant.
DICOM SEG · NIfTI
Plan draft
Treatment plan or follow-up draft for clinician review and signature.
Module-specific structured doc
Audit envelope
Every output ships with a hash chain back to inputs, weights and config.
AURORA audit (NDJSON)
03Case lifecycle6 steps · median target <100ms
  1. 01
    Bind
    Imaging or record arrives at PACS/EHR. AURORA binds the case by SOP/MRN, checks consent policy.
  2. 02
    Foundation pass
    Module foundation model produces a first-pass representation. Median target <100ms on partner-site hardware.
  3. 03
    Subsystem fan-out
    3 subsystems run in parallel; each writes its signal + uncertainty to the case.
  4. 04
    Synthesise
    Subsystem outputs are fused into the integrated assessment; the case is queued for the MDT surface.
  5. 05
    Clinician review
    MDT reviews on the AURORA surface. Every override carries a reason; the audit log writes durably before the next render.
  6. 06
    Sign + emit
    Signed report + structured artefacts flow back to PACS / FHIR / radiotherapy planning systems. Hash chain closes.
04Integrations the module speaks6 endpoints
PACS
DICOM C-STORE inbound + C-FIND outbound · STOW-RS for derived series.
EHR
FHIR R4 — DiagnosticReport, Condition, Observation, ServiceRequest. OAuth2 client credentials.
Lab feeds
HL7v2 (ORU^R01) for legacy molecular and laboratory results.
Auth
OIDC — Microsoft AD FS, Okta, Keycloak. Per-clinician identity in every override log entry.
Provenance
Sigstore-signed weights + container digests. Per-site federation key in Vault or KMS.
Telemetry
Off by default. When enabled, opt-in per-site; payload schema is in the module RFC.
05Per-subsystem, in detail3 units · independently installable
ARACH-ORIGIN
Membrane Origin
planned

Arachnoid splitting biology and developmental staging.

ARACH-PHYSICS
Cyst Physics
planned

Intra-cyst pressure, slit-flow and mass-effect simulator. The triage engine for the module.

ARACH-FORGE
Surgical Forge
planned

Comparative endoscopic vs open fenestration planning, with patient-specific risk envelopes.

Reversibility
Nothing the module installs is destructive. Uninstall removes containers + audit pointer; underlying records are untouched.
Determinism
Pinned commit + container digest + weights hash + dataset hash. Every AURORA-ARACH run is re-runnable and re-attributable.
Air-gap parity
Air-gapped deployments produce byte-identical outputs to networked deployments on identical inputs. No silent telemetry, ever.
Override SLO
Every clinician override is logged ≤ 200ms after the action; the log is durable before the next prediction renders.
V · Working papers

Our own writing on AURORA-ARACH.

3 drafts by the module team and pilot collaborators. Each documents one slice of the substrate — methods, evaluation protocol, lessons. Slot PDFs in as they're ready; the entries point to placeholders until then.

⚠ DRAFTS · DOI-STAMPED AT PUBLIC ALPHA · NO EXTERNAL "EVIDENCE LIBRARY" SHIPPED ON THIS PAGE
VI · Endpoints we will track

The metrics that matter over a lifetime.

These are the endpoints AURORA-ARACH is built to measure across pilot deployments. The targets below are pilot goals, not retrospective results.

−38%
target
Unnecessary fenestrations

On paediatric incidentaloma cohorts (target).

+12%
target
Symptom resolution @ 6mo

Among triaged surgical candidates.

0.89AUC
target
Mass-effect prediction

ARACH-PHYSICS on open registry data.

−25%
target
Unnecessary follow-up imaging

Surveillance cadence tuned to physics-band.

100%
target
Auditable override rate

Every override logged with reason.

+8%
target
Patient comprehension

Family-rated clarity of triage outcome.

⚠ PILOT TARGETS · NOT RETROSPECTIVE RESULTS · TO BE VALIDATED AT PUBLIC ALPHA
VII · Install AURORA-ARACH

From pip install to a hospital deploy in one afternoon.

Available to pilot partners today on private registries. At public alpha (Q4 2026) the same images, weights and signatures ship under MIT on public registries. For the full per-product download grid, see the unified download page.

step 1 of 3
pip install aurora-arach
step 2 of 3
aurora doctor arach
# → AURORA-ARACH  ✓ python  ✓ physics  ✓ forge
# → three subsystems loaded
step 3 of 3
from aurora.arach import triage
out = triage(case_id="bench/arach/case-0011")
print(out.physics_band)         # → "low mass-effect · σ 0.07"
Hardware
CPU · NVIDIA · AMD · Apple silicon
OS
Linux · macOS · Windows · WSL
Deploys
Cloud · On-prem · Air-gapped · Edge
Telemetry
Opt-in · Off by default

Hardware footprint, in practice

AURORA-ARACH is designed to run on hardware that already exists inside hospital networks. CPU-only inference is supported for the lighter subsystems; the heavier ones benefit from a recent GPU but do not require one. A single modern workstation handles routine cases under the latency target.

Networking and consent

Federated deploys do not require open inbound ports. The runtime opens an outbound mTLS connection to the federation control plane; model updates are signed, audited and pulled. Patient data never traverses the federation. Consent metadata is a first-class object — subsystems with an explicit consent dependency refuse to run on records that lack the appropriate cohort policy.

Migration paths

Most pilot sites land on AURORA-ARACH with an existing system in place. The recommended path is: install alongside, compare outputs on a held-out cohort for one quarter, then move read-only surfaces to AURORA, and decide on the rest. Reversibility is a design goal — nothing in the install creates lock-in.

Download grid

For the full per-product, per-platform download buttons (macOS / Windows / Linux installers + pip / docker / helm / rust commands), see the unified download page. Each subsystem of AURORA-ARACH is independently downloadable there.

VIII · Questions

The honest questions on AURORA-ARACH.

Eight diseases is the beginning.

AURORA is in private pilot today and opens to the world at public alpha in Q4 2026 under MIT. If you carry the weight of these diseases — as a clinician, scientist, builder, patient or advocate — there is a seat at the table.

Changelogv0.6.0