Overview

Most endovascular imaging tools image sideways. The catheter tip passes a lesion, the sensor looks outward through the vessel wall, and the physician builds a picture of what was just beside the catheter — after the fact, often requiring a cleared passage to get there.

The Scanning Fiber Endoscope (SFE) images forward. Combined with Forward-Looking OCT and full-color RGB visualization, the physician sees the anatomy directly ahead of the catheter tip in real time — before committing to the next move. This document describes clinical scenarios where that distinction is not a technical footnote. It is the procedure.

Each case below is illustrated with a figure brief for an animator, AI image creator, or medical illustrator. Flushing protocols (saline, upstream flow restrictor) are noted per case and should be verified with interventional physicians before publication.

Endovascular neurosurgery operates in vessels measured in millimeters, often occluded, often tortuous. The physician needs to know what is ahead of the catheter tip — not just beside it. These three cases illustrate where forward-view imaging directly changes the procedure.

CASE 1: Acute Ischemic Stroke — Clot Localization and Thrombectomy Guidance 

The clinical moment:  A thrombectomy catheter is advanced toward a suspected clot in a cerebral vessel. The vessel proximal to the occlusion may be partially open; the occlusion itself is an unknown mixture of fibrin, platelets, and red cell aggregates. The physician needs to locate the clot face precisely before deploying the retrieval device.

What SFE RGB + Forward OCT shows:  As the catheter approaches, the SFE provides a direct forward color view of the clot face — its texture, boundary with the vessel wall, and any irregular protrusion or soft margin. Switching to forward OCT adds subsurface depth characterization of the clot at ~3 mm ahead of the tip, helping the physician judge consistency (soft thrombus vs. organized fibrin) before selecting retrieval technique.

How the procedure changes:  The retrieval device deploys at the correct position, confirmed visually rather than inferred from roadmap fluoroscopy. The physician can see whether the stent retriever has engaged the clot face before activation.

CASE 2: Carotid Bifurcation — Imaging Before or After Carotid Stenting

The clinical moment:  A patient presents with carotid artery disease — partial obstruction at the bifurcation, either as a pre-procedural assessment or post-stent follow-up. The physician needs to assess the anatomy at the bifurcation point: the degree of stenosis, the texture of the lesion, and how the branches divide.

What SFE RGB + Forward OCT shows:  The SFE is advanced to the bifurcation. The forward color view shows the branch point directly — both the internal and external carotid ostia visible simultaneously. Forward OCT characterizes the vessel wall and lesion at tissue level immediately ahead. The physician sees the anatomy before committing the catheter past the bifurcation.

Why this moment is distinct:  Advancing a catheter past a bifurcation and imaging backward requires the vessel to already be traversed. The forward view allows the physician to assess the bifurcation from the approach — planning stent landing zone and coverage before any commitment.

CASE 3: Intracranial Stent Placement — Real-Time Imaging During Deployment

The clinical moment:  An intracranial stent is being placed for atherosclerotic stenosis or aneurysm management. The physician needs to confirm landing zone anatomy, observe stent expansion during deployment, and assess apposition after — ideally without multiple catheter exchanges.

What SFE RGB + Forward OCT shows:  Before deployment: the SFE forward view confirms the target segment is visible, the landing zone is identified, and the stent delivery system is positioned. During deployment: the SFE images the stent expanding in real time from within the catheter lumen — a view that is geometrically impossible for a side-viewing device to provide during deployment. After deployment: OCT can be activated to assess wall apposition and any edge dissection if a plaque or irregularity is encountered.

Clinical note:  Real-time imaging during stent deployment is a capability gap that currently requires inference from fluoroscopy alone. The SFE forward view does not replace fluoroscopy but adds direct tissue-level information at the moment of deployment that no current intravascular imaging modality provides in the forward direction.

These cardiac cases focus on anatomical situations where forward visualization is the enabling capability — not an improvement on an existing workflow, but access to a moment in the procedure that currently has no imaging at all.

CASE 1: Chronic Total Occlusion (CTO) — Crossing Under Direct Forward Visualization

The clinical moment:  A coronary guidewire approaches the proximal cap of a CTO. The physician must decide where to engage the cap, what material is directly ahead of the wire tip, and whether the crossing trajectory is toward the true lumen or subintimal space. This decision is currently made from fluoroscopy, CT roadmap, and operator experience. No imaging modality currently shows the physician what is directly ahead of the wire before engagement.

What SFE RGB + Forward OCT shows:  As the catheter advances to the proximal cap, the SFE forward view shows the cap directly — its surface texture, boundary with the surrounding vessel wall, and any visible channel or soft margin. Forward OCT characterizes tissue at ~3 mm depth ahead of the tip: distinguishing fibrous cap material from organized thrombus or calcified nodule. The physician chooses the crossing point with direct forward tissue intelligence.

After crossing:  Once the true lumen is accessed, the SFE confirms entry: the vessel opens ahead, the forward view transitions from occluded tissue to an open lumen. This is the crossing confirmation moment — currently inferred from pressure wire or contrast injection, now visible directly.

CASE 2: Post-MI Coronary Evaluation — Navigating Constricted Vessels Without Blind Advancement

The clinical moment:  Following a myocardial infarction, the physician evaluates non-culprit vessels to understand the extent of disease. Some segments are narrowed but not occluded. Advancing an imaging catheter blindly past a tight stenosis carries risk — the physician cannot see what the catheter tip is pushing against. In vessels where a side-viewing catheter cannot be positioned without first crossing the lesion, the forward view provides information before that commitment.

What SFE RGB shows:  The SFE is advanced to the narrowed segment. The forward color view shows the constriction ahead — the lumen narrows in the visual field, the physician sees the degree of narrowing and the texture of the wall directly ahead before deciding whether and how to advance. If a plaque or lesion surface is visible, the physician can assess it forward before crossing.

Adding OCT selectively:  If the forward RGB view reveals a lesion of interest — an irregular surface, a visible plaque — the physician can activate forward OCT to characterize the tissue at depth. This does not require crossing the lesion first. It is assessment from the approach.

This case is not about identifying vulnerable plaques systematically. It is about giving the physician a forward view of what is directly ahead before committing the catheter — in a vessel segment that is too narrow or too diseased to traverse blindly with confidence.

Urological endoscopy operates in a naturally irrigated environment — the bladder and upper urinary tract are routinely flushed with saline as part of standard cystoscopic procedure. This creates favorable conditions for optical imaging. These two cases represent distinct clinical problems where forward-looking SFE with OCT addresses unmet needs that current instruments cannot reach.

CASE 1: Bladder Carcinoma In Situ (CIS) — Depth Staging Under Direct Forward OCT

Collaborating investigator: Prof. Audrey Bowden, Vanderbilt University (NIH R01 — bladder CIS staging program). VerAvanti is exploring a prototype development sub-contract under Prof. Bowden's program, with AI integration planned in subsequent years.

The clinical moment:  Bladder carcinoma in situ (CIS) is flat, invisible to white-light cystoscopy, and has a high risk of progression. Blue-light fluorescence cystoscopy (BLC) reveals the lesion — it fluoresces pink under violet light — but cannot determine invasion depth. Staging whether the cancer is confined to the urothelium (Ta/T1) or has invaded the muscularis propria (T2) currently requires biopsy and pathology, which delays treatment decisions and carries sampling error risk.

What SFE forward OCT provides:  After BLC localizes the lesion, the SFE is advanced with its forward-facing OCT toward the fluorescent region of the bladder wall. Forward OCT delivers depth-resolved tissue characterization of the wall directly ahead of the catheter tip — urothelium, lamina propria, and muscularis propria as distinct signal layers. The physician assesses invasion depth in real time, from the approach, without contacting the lesion surface first.

Why forward-facing geometry matters here:  The bladder wall is a curved surface. A side-viewing catheter requires extreme maneuvering to achieve a perpendicular viewing angle on a flat bladder wall lesion — and often achieves only a glancing view. A forward-facing catheter aimed at the wall achieves the perpendicular depth profile naturally, by design.

CASE 2: Ureteroscopy and Kidney Stone Navigation — Forward Image-Guided Access

The clinical moment:  A ureteroscope is advanced into the ureter toward the renal pelvis to locate and treat a kidney stone. The ureter is narrow, tortuous in the upper segment, and the stone may be partially obstructing the lumen. The physician advances with fluoroscopic guidance but has no direct forward image of what the scope tip is approaching — the stone itself, the ureteral wall, or a junction ahead.

What SFE RGB + Forward OCT shows:  The SFE acts as a guidewire-scale imaging element — small enough to navigate the ureter with an eye at the tip. As the catheter approaches the stone, the forward RGB view shows the stone directly: its surface, its relationship to the ureteral wall, and any navigable space around it. The physician does not advance blindly into an obstruction. If the stone is only partially occlusive, the forward view reveals the remaining lumen and guides access around the stone for laser lithotripsy positioning.

After the stone is accessed:  Following fragmentation, the SFE forward view confirms that the lumen is clear ahead. No additional contrast injection is needed to assess passage — the physician sees it directly.