Abdominal Wall & Post-Op Imaging : Diagnostic Framework

v3

Abdominal Wall & Post-Op

Diagnostic Framework IRHAI Safety Engine Active

Created By

Dr. Sharad Maheshwari, MD

✉ imagingsimplified@gmail.com

Diagnostic Engine v3

Clinical Decision Support Classify + Grade + Act + Audit

Deterministic Reasoning Engine v3

Incorporates longitudinal intelligence, oncology flags, and an IRHAI safety validation layer to detect critical discrepancies.

Ctrl/Cmd + Enter Generate Report Esc Clear Engine

❏ L1: Input Features

1a. Post-Op Timeline Acute (< 5 Days) Expected (5-7 Days) Subacute (8-14 Days) Chronic (> 14 Days) Non-Operative / Native

1b. Temporal Context (Prior Scan) No Prior Scan / N/A New Finding Stable Increased Size / Worsening Decreased Size / Resolving

2. Collections & Fluids

Collection Present

Small (< 3 cm) Moderate (3-5 cm) Large (> 5 cm) Multi-compartment / Tracking Thick / Enhancing Rim Gas / Air bubbles Hyperdense (>30 HU)

Contrast Extravasation

3. Fascial Integrity

Wall Bulge (Intact Fascia) Fascial Defect (Hernia)

Wide Neck Narrow Neck Contents present in sac Fluid/Edema in sac

4. Tracts / Communication No anomalous tracts seen Tract extending to Skin surface Tract communicating with Bowel Communicates with Peritoneum (Leak)

5. Bowel Dynamics

Diffuse Dilatation Transition Point (Obstruction) Reduced / Absent Enhancement

6. Oncology & Audit Flags

New Wall Nodule (e.g. SMJ) Irregular Mass / Rapid Growth Peritoneal Deposit / Nodularity

Live Rule Traceability (Audit Log)

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⚙ L2/L4: Engine Output Layer

IRHAI Safety Active SM-SUI Protocol

Select radiologic features on the left to trigger the SUI protocolization and Safety engine.

📄 L5: Auto-Generated Report

Translates logic into a dictation-ready macro.

Copied to clipboard!

Introduction

Stop Describing. Start Classifying.

This framework shifts diagnostic reporting from simple morphological description to actionable clinical classification, localization, and consequence prediction.

! The Non-Negotiable Core

Every case evaluation must systematically answer these five questions.

• 1. Where is the pathology? (Layer + Compartment)
• 2. What is it? (Mandatory Classification)
• 3. Is there a complication?
• 4. Is there a communication? (Skin / Bowel / Peritoneum)
• 5. Does it change management?

💡 Clinical Translation

Surgeons aren't reading your report for fun; they need a surgical roadmap. They need to know if they should operate today (strangulation, active leak), tomorrow (abscess), or never (simple seroma). "There is fluid" is useless. "There is an abscess" is actionable.

Mentor Mode: The Core Shift

✕ "Describe what you see"

✓ "Classify + Grade + Act"

"Your reports become decision tools, not descriptions. Your AI becomes deterministic, not generative."

▣ Global Post-Op Checklist

Systematic sweep parameters and expected vs. pathological findings.

Systematic Sweep Areas

▸ Abdominal wall

▸ Organs

▸ Peritoneum

▸ GI tract

▸ Surgical bed

▸ Urinary system

▸ Drains

▸ Vascular

▸ Retroperitoneum

▸ Lung bases

✓ Expected Early Post-Op Findings

Pneumoperitoneum, Small fluid volumes, Fat stranding, Presence of surgical material (clips, hemostatic agents).

Spatial Mapping

Layer-Based Anatomy Model

Understanding the exact anatomical layer is crucial for the "Where" step. Click a layer to see specific pathology tracking rules.

Superficial → Deep

1. Skin Superficial

2. Subcutaneous tissue Camper's & Scarpa's Fascia

Superficial

3. Ext. Oblique / Rectus Intramuscular

4. Int. Oblique Intramuscular

5. Transversus abdominis Intramuscular

6. Transversalis fascia Deep

7. Extraperitoneal space Deep

8. Peritoneum Boundary

⚙ Layer Analysis Engine

←

Select a layer from the anatomy model.

Radiology Tracking Rule

💡 Expert SME Insight

Associated Pathologies (Non-Surgical)

Pathology Matrices

Complications, Hernias & Analytics

Comprehensive topographical classification, volume indices (Tanaka), and interactive evaluation of abdominal wall hernias and modern repairs.

Mandatory Hernia Complication Check

Always systematically assess and report: Obstruction, Strangulation (Ischemia), and Incarceration.

⚠

⚙ Hernia Topography Engine

Determine the exact hernia classification based on anatomical landmarks.

1. Anatomical Region Select Region... Groin / Inguinal Area Midline Lateral / Flank Previous Surgical Scar Internal Abdomen

Relation to Inguinal Ligament Select relation... Above Ligament Below Ligament

Relation to Inf. Epigastric Vessels Select relation... Medial (Hesselbach's Triangle) Lateral (Deep Ring)

Diagnostic Classification

Awaiting Inputs...

Groin Topography Map

Right side anatomy. Visualizing the relationship between defects and vascular landmarks.

Inguinal Ligament

Inf. Epigastric Art.

Indirect
(Lateral)

Direct
(Medial)

Femoral
(Below)

Volume Analytics: Tanaka Index & LOD

Crucial for massive incisional hernias to evaluate risk of Abdominal Compartment Syndrome upon reduction.

$$\text{Tanaka Index (\%)} = \left( \frac{\text{Hernia Sac Volume (HSV)}}{\text{Abdominal Cavity Volume (ACV)}} \right) \times 100$$

⚙ LOD Calculator

Direct Volume Entry 1D Measure (Ellipsoid Formula)

Enter volumes directly if obtained via automated 3D CT volumetry software.

Approximates volume using V ≈ 0.52 × L × W × D. Enter maximum Craniocaudal (L), Transverse (W), and AP (D) diameters in cm.

HSV (cc/cm³)

ACV (cc/cm³)

1. Hernia Sac Dimensions

• L: Sagittal neck to distal margin.
• W: Axial max left-to-right span.
• D: Axial fascial defect to anterior tip.

L

W

D

2. Abdominal Cavity Dimensions

• L: Inner diaphragm dome to symphysis pubis.
• W: Max transverse inner-wall to inner-wall @ L3-L4
• D: AP inner anterior wall to vert body @ L3-L4

L

W

D

Loss of Domain (LOD): A condition where a massive proportion of abdominal contents reside chronically outside the peritoneal cavity.

⚠

Rule of Thumb: A Tanaka Index > 25% indicates significant LOD. Attempting primary closure directly risks Abdominal Compartment Syndrome.

Modern Surgical Anatomy Planes

Radiologists must understand mesh planes to evaluate post-op complications correctly.

• Onlay Mesh placed anterior to the anterior rectus sheath. Risk: High rate of seromas due to large subcutaneous dissection.
• Retrorectus (Sublay) Gold Standard Mesh between rectus abdominis muscle and posterior rectus sheath (Rives-Stoppa). Excellent vascularization.
• eTEP MIS Approach extended Totally Extraperitoneal. Mesh in retrorectus space. Peritoneum remains closed; fluid collections here are extraperitoneal.
• TAR (Transversus Abdominis Release) Component separation cutting the transversus muscle to advance fascia medially. Creates a massive preperitoneal space for mesh.

Student Glossary & Acronym Decoder

Common surgical and radiological jargon translated for clarity.

Pathology States

Incarceration Hernia contents are "stuck" outside and cannot be manually pushed back (irreducible). Blood flow is still okay.

Strangulation The hernia is so tightly stuck that the blood supply is cut off (Ischemia). Surgical emergency to prevent necrosis.

Ileus vs. Obstruction Ileus: bowel "falling asleep" (diffusely dilated). Obstruction: physical blockage (dilated upstream, collapsed downstream at transition).

Measurements

HSV Hernia Sac Volume. The volume of contents sitting *outside* the normal cavity.

ACV Abdominal Cavity Volume. The total volume of the main abdominal cavity.

Ellipsoid Formula Math shortcut for radiologists. Measure L, W, D and multiply by ~0.52 to approximate volume in cc without 3D tracing.

Surgical Pre-Op (LOD)

PPP Progressive Pneumoperitoneum. Pumping air into the abdomen weeks before surgery to stretch muscles and make room for LOD organs.

Botox (BTA) Botulinum Toxin A. "Chemical component separation." Injected into abdominal wall muscles pre-op to paralyze and stretch them.

Component Separation Slicing specific fascial layers (e.g., TAR) to allow muscles to slide medially and close giant gaps without tension.

Abdominal wall post-op complications categorized by their typical presentation timeline.

Acute (0–7 days)

Hematoma, Seroma, Abscess, Wound dehiscence, Subcutaneous emphysema.

Rule: Differentiate simple fluid (seroma) from hyperdense (hematoma) or rim+air (abscess).

Subacute (1–4 weeks)

Organizing hematoma, Sinus tract, Early fistula, Mesh-related infection.

Rule: Look for anomalous communications indicating fistulization.

Chronic (>1 month)

Incisional hernia, Chronic sinus, Enterocutaneous fistula, Mesh complications, Scar endometriosis.

Rule: Assess fascial defects and contents carefully.

Specific post-operative complications mapped by organ system.

Hepatobiliary

• Abscess
• Biloma / bile leak
• Infarct

Pancreas

• Leak / fistula
• Pseudocyst
• Necrosis

Retroperitoneum

• Lymphocele
• Psoas abscess
• Tracking infection

Gastrointestinal (GI)

• Anastomotic leak
• Ileus vs obstruction
• Ischemia

Genitourinary

• Urine leak
• Urinoma
• Altered nephrogram

Vascular

• Active bleed
• Thrombosis
• Infarct

Watch Out

High-Yield Pitfalls & Truths

Common cognitive and interpretive errors in post-operative imaging. Click cards to reveal the radiologic truth and the underlying pathophysiological *why*.

❌ Air = Leak

Truth Air ≠ leak in the early post-op period. Pneumoperitoneum is expected.

Why? Room air/CO2 gets trapped during surgery. It takes 7-14 days to absorb. Worry only if air increases over time or is focally clustered around an anastomosis.

❌ Collection = Abscess

Truth Collection ≠ abscess. Must classify (seroma, hematoma) before calling it infected.

SME Clinical Rule The body responds to surgical trauma by producing sterile serous fluid with expected stranding. An abscess requires thick enhancing rim/gas. Always correlate with clinical markers.

❌ Drain in place = Safe

Truth Drain ≠ resolution. Collections can loculate or track away from the drain.

Why? Drains clog with fibrin/clots. Also, the abdomen is compartmentalized. A drain in the right gutter won't drain a left subphrenic abscess. Follow the fluid, not just the tube.

❌ Small lesion = Benign

Truth Small lesion ≠ benign. Watch out for Sister Mary Joseph nodules.

Why? The umbilicus has rich vascular/lymph connections. A tiny 1cm nodule there post-GI surgery might be the only sentinel sign of metastatic peritoneal carcinomatosis spreading.

❌ No PO Contrast is Fine

Truth No oral contrast → missed leak. High index of suspicion needed.

Why? IV contrast shows wall vascularity, but positive oral contrast is the gold standard to prove an anastomotic defect. If contrast spills out, the leak is definitive.

❌ Obstruction rules all

Truth Richter’s hernia often presents with NO systemic bowel obstruction.

Why? Only one side (antimesenteric wall) of the bowel is pinched. The main lumen stays open, so stool passes, but the pinched wall becomes ischemic and perforates silently.

Click any card to flip and reveal the diagnostic truth.