Staging a pancreatic head mass for resectability

CT

First and second year — the floor first, then every step

The report is a surgical document: the degree of circumferential contact with named vessels decides the operation.

Orient first

  • Resectability is defined by VASCULAR CONTACT expressed as a proportion of the vessel circumference, not by tumour size. The conventional divide is 180 degrees: contact of 180 degrees or less versus more than 180 degrees ("abutment" versus "encasement").
  • The vessels that matter are the SMA, coeliac axis and common hepatic artery on the arterial side, and the SMV and portal vein on the venous side. Each must be named separately with its degree of contact.
  • Venous contact is more often reconstructable than arterial contact, so the two are reported separately rather than as a single verdict.
  • A borderline-resectable tumour goes to neoadjuvant therapy rather than straight to theatre, so getting the degree right changes the treatment pathway, not just the wording.
  • ISOATTENUATING tumours exist and are not rare; secondary signs — duct cut-off, the double duct sign, distal atrophy, and an abnormal contour — may be the only evidence.

Acquire the study

  • A dedicated pancreatic protocol: non-contrast, LATE ARTERIAL (pancreatic parenchymal, roughly 40–45 s) and PORTAL VENOUS phases, thin slices.
  • The pancreatic parenchymal phase is where an isoattenuating tumour becomes conspicuous against enhancing parenchyma — a portal-venous-only study understages.
  • Thin-section reformats in coronal and sagittal planes, plus curved reformats along the vessels where available.
  • Confirm the phase from the vessels before judging anything — see the CT phases primer.

The manoeuvre

  • Locate the mass and measure it in three planes; if no discrete mass is visible, report the secondary signs explicitly.
  • For the SMA: state the degree of circumferential contact in degrees, and whether the fat plane is preserved.
  • For the coeliac axis and common hepatic artery: state contact and any variant anatomy, particularly a replaced or accessory right hepatic artery, which alters the operation.
  • For the SMV and portal vein: state contact, and describe any narrowing, contour deformity or thrombus, and the length of any involved segment.
  • Assess the duct: cut-off level, upstream dilatation, the double duct sign, and distal parenchymal atrophy.
  • Assess for METASTASES: liver, peritoneum, ascites, and distant nodes.
  • Assess regional nodes by short axis and station.
  • Conclude with a resectability category using a named system and give its version.

What confirms it

  • Resectable requires no arterial contact and no or limited venous contact with a reconstructable vein, with no metastatic disease.

What licenses you to exclude it

  • ⚠️ CT does not exclude small-volume PERITONEAL or LIVER metastases. State that, since staging laparoscopy exists precisely because of it.
  • A portal-venous-only study cannot exclude an isoattenuating tumour — report the limitation and recommend a pancreatic protocol.
  • Absence of a visible mass with a duct cut-off does not exclude tumour, and should be reported as suspicious rather than negative.

The classic misread

  • Reporting "abuts the SMA" without a degree of contact.
  • Missing a replaced right hepatic artery, which changes the surgical approach.
  • Staging on a portal-venous-only study.
  • Reporting the mass and not answering resectability.

Reference values

Each value carries the caveat that keeps it from being misused. Normal limits and diagnostic criteria are kept apart on purpose: a disease cut-off read as a normal range is the more dangerous mistake.

Normal limits

  • Superior mesenteric artery · Aortomesenteric angleapproximately 25–60°

    Sagittal reformatted CT or MR angiogram. The angle between the long axis of the aorta and the proximal superior mesenteric artery at its origin.

    An angle under about 22–25° WITH the compatible clinical picture and duodenal compression supports SMA syndrome — the angle alone diagnoses nothing, and thin asymptomatic patients commonly have narrow angles.

    CT · MRI

  • Superior mesenteric artery · Aortomesenteric distance at the duodenal crossing

    approximately 10–28 mm; under about 8–10 mm supports compression

    Measured where the third part of the duodenum (or the left renal vein) crosses between aorta and SMA. Both the angle and the distance must agree with the clinical syndrome — incidental narrow measurements are common.

    CT · MRI

  • Superior mesenteric vein · Calibre and position relative to the SMA

    similar in calibre to the companion SMA; the SMV normally lies to the RIGHT of the SMA at the mesenteric root

    Position outranks millimetres — SMV to the left of the SMA is the midgut-malrotation clue and belongs with the whirl-sign search, not with a calibre call. Acute thrombosis expands the vein and takes enhancement; chronic occlusion recanalises as cavernoma-like collaterals.

    USG · CT · MRI

  • Main pancreatic duct · diameter in the head/bodyup to 3 mm

    Tapers toward the tail; mild age-related dilatation is recognised.

    USG · CT · MRI

See it on real cases

Direct links to Radiopaedia — the reference article and worked cases with their images. Each opens on Radiopaedia.

Key papers

Reviews and guidelines from RSNA, ESR and related journals. Each opens at its DOI.

  1. Pancreatic Adenocarcinoma Staging in the Era of Preoperative Chemotherapy and Radiation Therapy ↗Zins M, Matos C, Cassinotto C · Radiology 2018RSNA · PubMed
  2. Imaging diagnosis and staging of pancreatic ductal adenocarcinoma: a comprehensive review ↗Elbanna KY, Jang HJ, Kim TK · Insights into Imaging 2020ESR · PubMed
  3. Imaging Assessment of Pancreatic Cancer Resectability After Neoadjuvant Therapy: AJR Expert Panel Narrative Review ↗Soloff EV, Al-Hawary MM, Desser TS, et al. · AJR 2022ARRS · PubMed
  4. White paper on pancreatic ductal adenocarcinoma from society of abdominal radiology's disease-focused panel for pancreatic ductal adenocarcinoma: Part I, AJCC staging system, NCCN guidelines, and borderline resectable disease ↗Kulkarni NM, Soloff EV, Tolat PP, et al. · Abdominal Radiology 2020SAR · PubMed
  5. How to approach pancreatic cancer after neoadjuvant treatment: assessment of resectability using multidetector CT and tumor markers ↗Jeon SK, Lee JM, Lee ES, et al. · European Radiology 2022ESR · PubMed

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