Is there a need for a CT scan of the pancreatic phase? A perfusion and simulation study of the pancreas, an HCC, and the kidney cortex

Abstract

Purpose

To explore the peak enhancement time of a hepatocellular carcinoma, the pancreas, and the kidney cortex and its determinants.

Materials and Methods

We obtained a time enhancement curve from the perfusion CT scans of 11 advanced HCC patients (40 volumes at 1.25 s time interval, slab slice 90 mm, bolus of 50 ml of iodinated contrast agent, 350 g iodine/ml, flow 5 ml/s). Small regions of interest were drawn on the abdominal aorta, the HCC, the cortex of the right kidney, and on the pancreas. The behavior of the contrast agent in the capillary and in the surrounding tissue was further explored with a finite element model.

Results

The peak enhancement time of the pancreas did not differ from that of the HCC (10±3 vs. 11±4 s, p=0.9), while the peak enhancement time of the kidney tended to be a few seconds earlier (8±1 s, p=0.082 vs. pancreas and p=0.069 vs. kidney). Simulation showed that the time span in which the tissue enhancement remained within 10% of its peak value was similar across all capillary densities and ranged between 26−38 s for a capillary density of 0.00125 per mm to 30–60 s for a capillary density of 0.01.

Conclusion

The plateau tissue enhancement clinically acquired in the “late arterial phase” should be adequate both for the detection of hypervascular liver lesions such as HCCs and for obtaining peak pancreatic enhancement to detect hypovascular lesions.

Key Points

• The peak tissue enhancement time of an HCC, the pancreas, and the kidney cortex is similar

• The tissue peak enhancement time in the arterial phase is at the end of bolus transit

• Simulation shows that tissue enhancement peak time is a function of capillary density

Citation Format

• Cressoni M, Cadringher P, Colarieti A et al. Is there a need for a CT scan of the pancreatic phase? A perfusion and simulation study of the pancreas, an HCC, and the kidney cortex. Rofo 2025; DOI 10.1055/a-2516-3176

Zusammenfassung

Zweck

Untersuchung der Spitzenkontrastverstärkungszeit von hepatozellulärem Karzinom, Pankreas und Nierenrinde sowie deren Einflussfaktoren.

Materialien und Methoden

Wir haben Zeit-Verstärkungskurven aus Perfusions-CT-Scans von 11 Patienten mit fortgeschrittenem HCC erhalten (40 Volumina in 1,25 s Intervallen, Schichtdicke 90 mm, Bolus von 50 ml jodhaltigem Kontrastmittel, 350 g Jod/ml, Flussrate 5 ml/s). Kleine Interessensregionen wurden auf der Bauchaorta, dem HCC, der Nierenrinde und dem Pankreas markiert. Das Verhalten des Kontrastmittels in den Kapillaren und im umliegenden Gewebe wurde weiter mit einem Finite-Elemente-Modell untersucht.

Ergebnisse

Die Spitzenkontrastverstärkungszeit des Pankreas unterschied sich nicht von der des HCC (10±3 vs 11±4 s, p=0.9), während die der Niere einige Sekunden früher zu liegen schien (8±1 s, p=0.082 vs. Pankreas und p=0.069 vs. Niere). Simulationen zeigten, dass der Zeitraum, in dem die Gewebekontrastverstärkung innerhalb von 10% ihres Spitzenwertes blieb, bei allen Kapillardichten ähnlich war: Er reichte von 26−38 s bei einer Kapillardichte von 0.00125/mm bis 30–60 s bei einer Kapillardichte von 0.01.

Schlussfolgerungen

Die klinisch in der „späten arteriellen Phase“ erworbene Gewebekontrastverstärkung sollte sowohl für die Erkennung hypervaskulärer Leberläsionen wie HCC als auch für die Erzielung der Spitzenkontrastverstärkung des Pankreas zur Erkennung hypovaskulärer Läsionen geeignet sein.

Kernaussagen

• Die maximale Gewebeanreicherungszeit von HCC, Pankreas und Nierenrinde ist ähnlich

• Die Gewebespitzenverstärkungszeit in der arteriellen Phase liegt am Ende des Bolustransports

• Simulationen zeigen, dass die Spitzenzeit der Gewebeverstärkung von der Kapillardichte abhängt

Keywords

contrast agents - pancreatic adenocarcinoma - computed tomography - arterial phase - hepatocarcinoma - perfusion imaging

Publication History

Received: 16 November 2024

Accepted after revision: 09 January 2025

Article published online:
06 February 2025

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