REVIEW 3 major objections 7 minor 1 cited by
ETSM: Automating Dissection Trajectory Suggestion and Confidence Map-Based Safety Margin Prediction for Robot-assisted Endoscopic Submucosal Dissection
T0 review · 3 major / 7 minor · reviewed 2026-08-12 · deepseek-v4-flash
Pith's one-line read A regression network predicts safety margins for robotic endoscopic dissection with a mean absolute error of 3.18, enabling intraoperative visual guidance.
desk verdict The ETSM dataset is the real contribution, but the confidence-map label definition is broken as written and the headline MAE is not interpretable until it is fixed. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The load-bearing machinery is the confidence-map generation rule of Eq. (1): for each point in the dissection area, the confidence is the ratio of its distance to the nearest safety-margin point over its distance to the nearest trajectory point, $\frac{\sqrt{(x_e-x_a)^2+(y_e-y_a)^2}}{\sqrt{(x_t-x_a)^2+(y_t-y_a)^2}}$. Because a naive nearest-margin search can pick the wrong side of a curved margin, the paper adds an angular-difference search: find the nearest trajectory point, cast a ray from it through the area point, then select the margin point whose direction has the smallest angular difference from that ray; a distance threshold is introduced for curved cases. The second pillar is RCMNet, which uses a pre-trained DINOv2 ViT-B/14 encoder with LoRA fine-tuning, extracts multi-scale features from transformer blocks 3, 6, 9, and 12, and decodes them with an All-MLP network (channel unification, upsampling, concatenation, fusion MLP, and a 1-channel prediction head). Training uses a weighted MSE loss with weight 10 on pixels outside the safety margin, so the model learns to output zero confidence there. The trajectory-suggestion comparisons are carried out with behavior cloning, MID, and iDiff-IL.
What would settle it
Recompute the ETSM ground-truth labels by explicitly clamping or normalizing the Eq. (1) ratio to $[0,1]$, or by specifying the missing distance threshold, and re-run the RCMNet versus MAN/SASNet comparison. If the reported MAE of 3.18 at $532\times532$ shifts materially, or if the relative ordering of the models changes, the paper's central quantitative claim is not stable under the correct label definition. An even more direct check is to calculate the fraction of labeled pixels whose raw confidence exceeds 1 in the released dataset; a non-negligible fraction would confirm that the ground truth is not a proper confidence field.
Extended reading notes
Core claim
The paper's central claim is that the safety margin of an endoscopic submucosal dissection area can be represented as a continuous confidence field — value 1 on the optimal dissection trajectory, 0 on and outside the safety margin, smoothly decreasing in between — and that this field can be predicted directly by a regression network. On the ETSM test set, their RCMNet reaches a mean absolute error of 3.18 and a mean squared error of 344.40 at $532\times532$ resolution, beating the crowd-counting baselines MAN (MAE 3.68) and SASNet (MAE 4.19), and it also attains the lowest mean MAE under the four corruption categories. Qualitatively, the predicted maps track the gradient from trajectory to margin even in difficult cases, and the method is also applied to out-of-domain live porcine and patient frames. In the trajectory-suggestion half of the framework, behavior cloning with a CNN-MLP gives average displacement error 9.10, final displacement error 11.20, and Fréchet distance 20.14, outperforming MID and iDiff-IL. The authors frame these results as the first regression-based approach for delineating varying safety levels of dissection areas.
Load-bearing premise
The load-bearing premise is that the ground-truth confidence maps are a well-defined field whose values lie in $[0,1]$; the paper defines confidence as a distance ratio that can exceed 1 and introduces a distance threshold for curved cases without stating how the ratio is clamped or normalized.
Editorial extensions
If this is right
- RCMNet's predicted confidence maps can be overlaid on the endoscopic view in real time, giving the surgeon a graded 'safe–caution–danger' display during dissection.
- The angular-difference-based confidence generation handles curved dissection areas by avoiding opposite-margin misassignment, a property the authors demonstrate in Fig. 2.
- The regression formulation for safety-margin prediction outperforms the segmentation formulation, since segmentation methods achieve only roughly 0.45 IoU and are deemed unreliable for this task.
- Behavior cloning's trajectory suggestions (ADE 9.10) are accurate enough to serve as a starting point for automated dissection subtasks, though full autonomy is not claimed.
Reading between the lines
- Because the confidence value is a dimensionless pixel-distance ratio, converting it to physical units by calibrating pixel size from the endoscope's optics would make the reported MAE interpretable as a true margin error in millimeters; the paper does not perform that calibration.
- The current confidence module uses a single input frame while the trajectory module uses three frames; fusing temporal information into the confidence branch is a natural extension the paper lists as future work and is likely to reduce errors during tool-induced occlusions.
- The dataset comprises 21 ex-vivo porcine procedures with annotations by expert endoscopists; a multi-expert study measuring inter-annotator agreement on trajectory and margin placement would clarify how much of the 3.18 MAE is annotation noise rather than model error.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript introduces ETSM, a dataset of 1,849 short clips from ex-vivo porcine robotic endoscopic submucosal dissection (ESD), with annotations of dissection trajectories and safety margins, along with an angular-difference algorithm to generate confidence-map safety margins. The authors propose RCMNet, a DINOv2-encoder plus All-MLP-decoder regression network, to predict these confidence maps, and evaluate trajectory suggestion using behavior cloning (BC), motion indeterminacy diffusion (MID), and implicit diffusion policy imitation learning (iDiff-IL). The central quantitative claims are that BC achieves ADE 9.10 for trajectory suggestion and that RCMNet achieves MAE 3.18 for confidence-map prediction at 532x532 resolution, outperforming MAN and SASNet in in-domain and robustness evaluations. The out-of-domain evaluation is qualitative, showing predictions on live porcine and patient data.
Significance. If the confidence-map formulation is made well-defined and reproducible, the paper would contribute a useful dataset and a novel regression-based approach for safety-margin visualization in robot-assisted ESD. Strengths include the release of dataset and code, the use of a video-level train/test split, the inclusion of robustness evaluation under several corruption types, and the first application of a regression decoder with a pre-trained DINOv2 encoder to this task. The trajectory-suggestion comparison with three baselines is a reasonable contribution. However, the central quantitative claim—RCMNet's MAE of 3.18—depends entirely on the ground-truth confidence map definition, which as written is internally inconsistent and not a proper [0,1] confidence field. The concern raised in the stress-test note directly lands on this manuscript: Eq. (1) does not produce bounded confidence values and the text itself acknowledges that values exceed 1. This must be resolved before the reported numbers can be interpreted.
major comments (3)
- [Section II-A, Eq. (1)] The definition of the ground-truth confidence map is not well-defined. The text assigns confidence 1 to the dissection trajectory and 0 to the safety margin and its exterior, but Eq. (1) computes C = d_margin / d_trajectory. At a point on the trajectory, the denominator is zero, making C undefined or infinite; at the margin, C = 0. The sentence 'the confidence exceeds 1' in the following paragraph confirms that values are not clamped to [0,1]. Since the weighted MSE loss in Eq. (2) and all MAE/MSE values in Table I are computed against these labels, the reported MAE of 3.18 is not interpretable as an error on a confidence map. Please state the exact label-generation formula actually used (e.g., d_margin / (d_margin + d_trajectory)), or describe and justify a clamping/normalization step, and regenerate all reported results with the corrected formulation.
- [Section II-A, distance threshold] The 'distance threshold between the margin point and the area point' is introduced to handle curved dissection areas, but its value is never specified. Because this threshold directly affects which margin point is selected and hence the resulting confidence values, every number in Table I depends on this unspecified hyperparameter. This makes the algorithm non-reproducible. Please provide the threshold value, the units (pixels or millimeters), and the exact selection rule (e.g., the margin point with the smallest angular difference among those within T pixels).
- [Section III-C-2, Table I] The evaluation reports single MAE/MSE values per model with no standard deviations, confidence intervals, or repeated-seed experiments. The test set consists of 369 clips from four videos, so the observed difference between RCMNet (MAE 3.18) and SASNet (MAE 4.19) could be within run-to-run variability. Please report results over multiple seeds or provide a statistical test, and specify the numerical range of the confidence maps used in the metrics (e.g., 0–1 or 0–255) so that the MAE values are interpretable.
minor comments (7)
- [Section II-B-2-a] The word 'Intermediant' should be 'Intermediate'.
- [Section II-B-2-b] The decoder name appears inconsistently as 'All-MLP' and 'ALL-MLP'; please unify the terminology.
- [Section II-B-2-c] The phrase 'weight Mean Square Error' should be 'weighted Mean Square Error'.
- [Section III-A] The number '1, 849' contains an odd space; write '1,849'.
- [Table I] The table header 'Constrast' should be 'Contrast'.
- [Section III-C-1] The baselines MID and iDiff-IL are compared with BC, but the manuscript does not describe how these models were adapted to the ESD task or what hyperparameters were used; a brief implementation note would improve reproducibility.
- [Figures 5(b) and 6] The predicted and ground-truth confidence maps are shown with color gradients but no colorbar or value labels, making it difficult for the reader to judge quantitative agreement; adding colorbars would improve interpretability.
Circularity Check
No significant circularity: the confidence-map prediction targets are fixed by expert annotations and a deterministic distance-ratio algorithm, and RCMNet is evaluated against held-out labels without reusing the label-generation rule.
full rationale
The derivation chain is: DREAMS videos are recorded with an external robotic system (cited from prior work), expert endoscopists annotate dissection trajectories and safety margins, the paper's angular-difference algorithm converts those annotations into confidence maps, and RCMNet is trained to regress those fixed maps and is evaluated on held-out clips. No equation reduces the prediction to the label-generation rule: RCMNet's decoder does not take the trajectory or margin annotations as input at inference, and the angular nearest-margin selection is not re-run by the network. The reported MAE of 3.18 is therefore a genuine measure of how well the network reproduces the self-defined target, not a fitted parameter renamed as a prediction. The trajectory-suggestion evaluation (BC vs MID vs iDiff-IL) is likewise supervised against expert-annotated coordinates. References [9] and [10] are self-citations to the robotic platform used for data collection, but they are not invoked as a uniqueness theorem nor to forbid alternatives, and the dataset/code are released for external checking. The ambiguity in Eq. (1) -- confidence unclamped and undefined on the trajectory -- is a reproducibility and target-definition concern, not a circularity: it does not make the prediction equivalent to its input by construction.
Assumptions & free parameters
free parameters (3)
- Distance threshold for curved dissection areas =
Not reported
- 0.4 mm trajectory offset =
0.4 mm
- Outside-margin loss weight =
10
assumptions (2)
- domain assumption The expert-annotated trajectory and safety margin, converted by the angular-difference algorithm, constitute the ground truth for optimal dissection behavior.
- ad hoc to paper The confidence ratio in Eq. (1), after some unstated clamping or normalization, yields a valid [0,1] safety map.
Cite this review
Pith. "Pith review of ETSM: Automating Dissection Trajectory Suggestion and Confidence Map-Based Safety Margin Prediction for Robot-assisted Endoscopic Submucosal Dissection." pith.science (2026). https://pith.science/paper/VOB5ND7N
@misc{pith2026241118884,
author = {Pith},
title = {Pith review of: ETSM: Automating Dissection Trajectory Suggestion and Confidence Map-Based Safety Margin Prediction for Robot-assisted Endoscopic Submucosal Dissection},
year = {2026},
howpublished = {\url{https://pith.science/paper/VOB5ND7N}},
note = {Machine review of arXiv:2411.18884}
}
abstract
Robot-assisted Endoscopic Submucosal Dissection (ESD) improves the surgical procedure by providing a more comprehensive view through advanced robotic instruments and bimanual operation, thereby enhancing dissection efficiency and accuracy. Accurate prediction of dissection trajectories is crucial for better decision-making, reducing intraoperative errors, and improving surgical training. Nevertheless, predicting these trajectories is challenging due to variable tumor margins and dynamic visual conditions. To address this issue, we create the ESD Trajectory and Confidence Map-based Safety Margin (ETSM) dataset with $1849$ short clips, focusing on submucosal dissection with a dual-arm robotic system. We also introduce a framework that combines optimal dissection trajectory prediction with a confidence map-based safety margin, providing a more secure and intelligent decision-making tool to minimize surgical risks for ESD procedures. Additionally, we propose the Regression-based Confidence Map Prediction Network (RCMNet), which utilizes a regression approach to predict confidence maps for dissection areas, thereby delineating various levels of safety margins. We evaluate our RCMNet using three distinct experimental setups: in-domain evaluation, robustness assessment, and out-of-domain evaluation. Experimental results show that our approach excels in the confidence map-based safety margin prediction task, achieving a mean absolute error (MAE) of only $3.18$. To the best of our knowledge, this is the first study to apply a regression approach for visual guidance concerning delineating varying safety levels of dissection areas. Our approach bridges gaps in current research by improving prediction accuracy and enhancing the safety of the dissection process, showing great clinical significance in practice.
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Forward citations
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Reviewed August 12, 2026 · model on record in the stance chip above.
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