Skanda-0

Reads chest X-ray, CT and MRI, writes the report, and outlines the findings it reports

Results · By disease · Limitations · Files · Memory · int8 / int4 · Licence

Research use only. Skanda drafts findings for a radiologist to review. It is not a medical device and has not been cleared or approved for clinical use by any regulator.

✨ At a glance

72% CT finding named right MedGemma 27B: 49%

89% MRI finding named right MedGemma 27B: 42%

91% · 94% lesion-free CT · MRI cleared MedGemma 27B: 6% · 2%

4× · 22× · 12× box precision vs MedGemma 27B X-ray · CT · MRI

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🏁 Results

All numbers are percentages on held-out test cases. No test patient was seen in training.

	🩻 Chest X-ray · 111 films
Metric	MedGemma 27B	MedGemma + MAIRA-2	Skanda run 2†	Skanda-0
Abnormal flagged	90	91	85	84
Normals called normal	72	72	83	69
Right finding type	41	47	37	40.5
Box precision	6	–	28	25.5
Box recall	4	–	15.5	10
	🫁 CT · 340 cases
Abnormal flagged	97	–	80	82
Normals called normal	6	–	88	91
Right finding type	49	–	69	72
Box precision	1	–	20	22
Box recall	3	–	14	16
	🧠 MRI · 240 cases
Abnormal flagged	99	–	89	89
Normals called normal	2	–	97	94
Right finding type	42	–	87	89
Box precision	6	–	64	70
Box recall	8	–	59	65

_{Percent, higher is better; bold = best per row. MAIRA-2 reads chest X-rays only, so it has no CT or MRI numbers. ^† An earlier development checkpoint, shown for comparison; it is not published. Skanda-0 is the run-3 checkpoint.}

💡 What the numbers say

• 🫁🧠 On CT and MRI, Skanda is well ahead of MedGemma.
  • It names the right finding 72% / 89% of the time, against 49% / 42% for MedGemma 27B.
  • It clears 91% / 94% of lesion-free cases, where MedGemma clears 6% / 2%: it calls nearly every case abnormal.
• 🩻 On chest X-ray, Skanda-0 is a trade-off against the earlier run 2.
  • Finding type rose from 37% to 40.5%, but it clears fewer normals than run 2 (69% vs 83%) and finds fewer boxes (recall 10% vs 15.5%).
  • Each X-ray number moves about ±10 points by chance across 111 films. On the 106 dev films the same checkpoint cleared 74% of normals at 15.5% recall.
• 🎯 Skanda outlines; the baselines write coordinates. MedGemma and MAIRA-2 give boxes only as text. Skanda's box precision is 4× MedGemma's on X-ray, 22× on CT and 12× on MRI.
• 🩻 On X-ray boxes, MAIRA-2 alone is ahead. Read on the same 111 films in a later benchmark, MAIRA-2 reached box precision 30% and recall 13%, against Skanda's 24.5% and 9.5% (see the quantized builds below). MAIRA-2 is licensed for research use only.

📏 How it is measured

Metric	Meaning
Abnormal flagged	abnormal cases the model calls abnormal
Normals called normal	normal or lesion-free cases the model clears
Right finding type	abnormal cases where the model names a ground-truth finding class
Box precision / recall	X-ray: a predicted box counts when its centre lies inside a radiologist box of the same class. CT/MRI: box IoU ≥ 0.3 with a radiologist outline, matched one-to-one

• Chest X-ray: ChestX-Det test films, scored by the Skanda Radiology app's own benchmark. The same runner is used for every model. Skanda's numbers are the mean of two passes.
• CT and MRI: a fixed sample of held-out slices and volumes, with and without lesions. One script scores every model.
• Two reads of the same cases. The table above is from 1 November 2026. The quantized-build table below and the int8 / int4 cards use a later re-read (8 November), with every baseline served at bf16, 8-bit and 4-bit through the same stack. On X-ray the two reads differ by a few points (MedGemma 27B finding type 41% here, 36% there), within the ±10-point chance range of 111 films; CT and MRI reads of Skanda were identical.

🦠 Detection by disease

How often each model names each kind of finding, on the same held-out cases as the table above.

	Skanda leads	MedGemma leads
🩻 X-ray	consolidation 78% vs 69% · effusion 64% vs 30% (53% fused) · cardiomegaly 75% vs 25% · diffuse nodule 50% vs 0%	pneumothorax 100% vs 15% · atelectasis · nodule · mass · fibrosis · emphysema
🫁 CT	lung 92% vs 76% · liver 74% vs 57% · pancreas 46% vs 0% · mediastinum 69% vs 38%	colon 20% vs 13%
🧠 MRI	brain tumour 96% vs 74% · acute stroke 47 of 60 found vs 0	–

_{Groups under about 15 cases (kidney, mediastinum, colon, most rare X-ray labels) are directional only.}

🔍 Side by side

⚠️ Limitations

• Rare X-ray findings are weak. Skanda named pneumothorax on 15% of the films that have it (MedGemma 27B: 100%), and trails MedGemma on atelectasis, nodule, mass, fibrosis and emphysema. Do not use it for triage.
• It misses findings. The report often names fewer findings than a film has, and X-ray box recall is about 10%.
• CT outlines can follow enhanced vessels instead of the lesion, and CT box recall is 16%.
• Small, internal test sets. 111 X-ray films (about ±10 points by chance) and held-out cases from the training sources. There has been no external test set, no reader study and no radiologist review of its reports.
• Template reports. Evidence sentences come from measured masks and fixed templates; severity is a per-class constant.

📦 Files and loading

File	What it is
vlm/	Merged Qwen3-VL-30B-A3B (bf16 safetensors, 17 shards, LoRA merged) with tokenizer, processor and chat template
skanda_heads.pt	SAM 2.1 (image encoder and trained mask decoder), the [SEG] projector and the score head
skanda_config.json	[SEG] token id 151669, training arguments, calibrated gate thresholds per modality, hint thresholds
hint_scores.jsonl	Score-head outputs the hint thresholds were chosen on (validation and dev only, never test)

62.6 GB in total (58.3 GiB); see memory and quantization. The inference code is not public yet: it lives in the private GitHub repo Hitheshkaranth/skanda-grounding.

huggingface-cli download hitheshkaranth/Skanda-0 --local-dir skanda-0                  # bf16
huggingface-cli download hitheshkaranth/Skanda-0-int8 --local-dir skanda-0-int8        # int8 build of main
huggingface-cli download hitheshkaranth/Skanda-0-int4 --local-dir skanda-0-int4        # int4 build of main

# in a checkout of skanda-grounding
from PIL import Image
from skanda.serve import Skanda

sk = Skanda("skanda-0")                                        # vlm/ + skanda_heads.pt + skanda_config.json; int8/int4 load the same way
report, raw_text, finished, n_tokens = sk.read(Image.open("chest.png").convert("RGB"))

python -m skanda.serve --model skanda-0 --port 1234   # the HTTP server the Skanda Radiology app calls

💾 Memory and quantization

Memory (bf16, measured)

	Size	Notes
Download / disk	62.6 GB	58.3 GiB: vlm/ 57.9 GiB + skanda_heads.pt 0.43 GiB
Inference, steady	~68 GB	chest X-ray, CT/MRI slices and 32-slice volumes alike; one read at a time
Inference, peak	~93 GB	while loading the checkpoint and on the largest volumes

_{Measured on an NVIDIA DGX Spark (GB10, 128 GB unified memory) from node memory during run 3's test evaluation and app benchmark, minus the idle baseline. The server runs in a container capped at 112 GB.}

Hardware	Fits?
DGX Spark / GB10, 128 GB unified	✅ tested: everything here was trained and benchmarked on one
1 × 80 GB GPU (A100 / H100 80 GB)	⚠️ expected to fit: 62 GB of weights + activations; not tested
2 × 48 GB GPUs (device_map="auto")	⚠️ expected to fit; not tested
24–48 GB GPUs	❌ not at bf16; needs a quantized build (below)

Quantized builds

Weight-only builds of this checkpoint, with gates re-calibrated per build. Only the language model is quantized; the SAM 2.1 decoder, [SEG] projector and score head stay bf16. Each build's card has the full benchmark against MedGemma 27B, MAIRA-2 and MedGemma + MAIRA-2 at the matching precision.

	bf16 (this repo)	int8	int4
Download	62.6 GB	32.8 GB	18.2 GB
Method	–	int8 per-row	int4 group-128
🩻 X-ray right finding type	39	40.5	36
🩻 X-ray box precision	24.5	24	17.5
🩻 X-ray box recall	9.5	8.5	8.5
🫁 CT normals called normal	91	85	78
🫁 CT right finding type	72	72	74
🫁 CT box precision	22	21	19
🧠 MRI right finding type	89	87	80
🧠 MRI box recall	65	67	49
Loss per token on bf16's own replies	0.0823	0.0824	0.1181

_{Percent on the held-out test cases above (bf16 re-read with the same code and calibration as the builds). int8 is effectively lossless and is the recommended smaller build; int4 loses accuracy, most on MRI box recall.}

📜 Licence

CC BY-NC 4.0 (Creative Commons Attribution-NonCommercial 4.0): free for research and other non-commercial use, with attribution. Commercial use requires written permission from the author: open a request in this repository's Discussions. The licence text is in LICENSE; upstream licences and data attributions (Qwen3-VL, Sa2VA, SAM 2 and the training datasets) are in NOTICE. Research use only; not a medical device.

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_{Skanda · AI for healthier tomorrows}