Abdomen & Pelvis CT

What it does

Abdomen & Pelvis CT reads the highest-volume body CT in every phase it is acquired in: non-contrast, arterial, portal-venous and delayed or excretory, plus the non-contrast CT KUB and CT colonography. The run detects the phase of each series from the images, and each section uses only the phases it needs.

The result has two halves. The acute half answers the emergency questions: free air, free fluid or haemoperitoneum, bowel obstruction with its transition point, signs of appendicitis, urinary stones with hydronephrosis, and liver, spleen and kidney injury after trauma. The elective half segments more than a hundred structures with volumes and characterises lesions of the liver, pancreas, kidneys and adrenals with the management of the matching ACR incidental-findings white paper, a Bosniak class or a LI-RADS category.

Intended use

Decision support for the resident or emergency physician reading an acute abdomen at night, and for the radiologist who needs every incidental lesion handled consistently during the day. Every finding is located and measured.

Who it is for

Abdominal and emergency radiologists, emergency physicians, general and trauma surgeons, urologists, hepatologists and gastroenterologists. Developers use the run to add acute-abdomen triage, stone measurement or incidentaloma tracking to a worklist or reporting tool.

Accepted input

• All phases of one examination in the same upload, as DICOM CT series.
• Special protocols: CT KUB for renal colic, adrenal-protocol CT with delayed washout, prone and supine insufflated CT colonography.
• Prior abdominal CT in prior_files for lesion growth.

Phase requirements

Section	Phase needed
Urinary stones	Non-contrast CT KUB
Renal masses	Non-contrast and nephrographic, for enhancement in HU
Adrenal nodules	Unenhanced attenuation; adrenal protocol for washout
LI-RADS	Arterial, portal-venous and delayed, in patients at risk of hepatocellular carcinoma
Pancreatic lesions	Pancreatic or portal-venous phase
Abdominal trauma	Portal-venous, with arterial when acquired
CT colonography	Prone and supine insufflated series

Oral contrast, hip-prosthesis streak and noise in large patients are reported as quality flags; a section whose phase is missing is marked as not assessed.

Optional context

The clinical question (acute abdominal pain, renal colic, trauma, staging, liver surveillance), cirrhosis or other risk factors for hepatocellular carcinoma and known lesions go in clinical_context. A known risk population is needed before a LI-RADS category is assigned.

The result

One JSON result in sections; organ and lesion masks come as a DICOM label-map SEG.

Section	Content
Acute-abdomen triage	Worklist flags for free air, bowel obstruction, appendicitis, haemoperitoneum or active bleeding, ruptured aneurysm
Free air	Pneumoperitoneum location and volume, retroperitoneal gas
Free fluid	Volume, density (simple fluid or haemoperitoneum) and location
Bowel obstruction	Small- or large-bowel obstruction, transition point, closed-loop and ischaemia signs
Appendicitis	Appendix diameter, wall thickening and fat stranding, appendicolith, perforation or abscess
Urinary stones	Diameter, volume, HU and location (calyx, pelvis, ureter, vesicoureteric junction), hydronephrosis grade; gallstones
Abdominal trauma	Liver, spleen and kidney injury as none, low or high grade, bowel or mesenteric injury, active extravasation
Organ segmentation and volumes	More than 100 structures with volumes and organomegaly flags
Liver lesions	Count, size and Couinaud segment, with liver and segmental volumes
LI-RADS	Major features per observation (arterial phase hyperenhancement, washout, capsule, size, growth), LI-RADS category and treatment response
Pancreatic lesions	Ductal adenocarcinoma with its location, duct dilatation, cyst size and features
Renal masses	Mass or cyst size, enhancement, Bosniak class for cystic masses, solid-mass management
Adrenal nodules	Size, unenhanced HU (10 HU or less suggests lipid-rich adenoma), washout
CT colonography	Polyps of 6 mm or more with size and segment, extracolonic findings
Draft report	Opt-in (options.report): an English narrative that interprets the result for the reader (findings, impression, limitations); every number is checked against the findings

Standards

• DICOM: SR TID 1500 Measurement Report; SEG (label map) for organs and lesions; GSPS, Encapsulated PDF and FHIR DiagnosticReport.
• Lesion management: ACR incidental-findings white papers on adrenal masses (2017), renal masses (2018) and pancreatic cysts (2017); Bosniak 2019; LI-RADS CT/MRI v2018 and the LI-RADS CT/MR treatment response algorithm v2024; C-RADS v2023 for colonography.
• Trauma: injuries of the spleen, liver and kidney are graded low or high, with the AAST organ injury scale 2018 as the reference; individual AAST grades are not assigned.