Value of dual-energy computed tomography quantitative parameters in differentiating neoplastic from bland portal vein thrombosis

Abstract

Background: Portal vein thrombosis (PVT) is a common clinical pathological state involving distinct pathophysiological processes. Accurate discrimination of PVT nature is of utmost importance for guiding treatment strategies, but histopathology has limitations and imaging lacks quantitative indices. This study aimed to evaluate the feasibility and diagnostic value of quantitative parameters from dual-energy computed tomography (DECT), an advanced technique that allows for such quantitative evaluation, in distinguishing neoplastic from bland PVT.

Methods: Computed tomography (CT) images of 173 patients with PVT (bland group, n=74; neoplastic group, n=99) were retrospectively analyzed. Portal venous phase iodine-based decomposition images were reconstructed to contrast iodine indices among groups, including thrombus iodine concentration (IC), normalized iodine concentration in the aorta (NIC-A), normalized iodine concentration in the portal vein (NIC-V), electron density (Rho), effective atomic number (Z), dual-energy index (DEI), and spectral slope (K). Diagnostic performance was evaluated using the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and accuracy. Univariate and multivariate analyses selected DECT parameters and created a nomogram for prediction.

Results: (I) The values of IC, NIC-A, NIC-V, Rho, Z, DEI, and K were significantly higher in the neoplastic group compared to the bland group (P<0.001). (II) The AUC using IC, NIC-A, and NIC-V to differentiate between neoplastic and bland PVT were 0.963, 0.970, and 0.969, respectively; using Rho, Z, DEI, and K, they were 0.732, 0.952, 0.949, and 0.933, respectively. All the quantitative parameters achieved high sensitivity and high specificity in distinguishing neoplastic from bland PVT. (III) A nomogram was developed to predict neoplastic PVT probability; its AUC, sensitivity, and specificity reached remarkable levels, with values of 0.994, 98.59%, and 97.96% in the training cohort and 0.940, 100%, and 92.00% in the test cohort, respectively.

Conclusions: The DECT quantitative parameters demonstrate significant potential as non-invasive markers for distinguishing between neoplastic and bland PVT.

Keywords: Dual-energy computed tomography (DECT); dual-energy index (DEI); electron density; iodine concentration (IC); portal vein thrombosis (PVT).

Figure 1

The flowchart of participants throughout the study. DECT, dual-energy computed tomography; PVT, portal vein thrombosis.

Figure 2

Box plot showing the range of IC (A), NIC-A (B), and NIC-V (C) for neoplastic and bland PVT on the portal phases. The IC, NIC-A, and NIC-V were significantly higher for neoplastic than for bland PVT on the portal phases. IC, iodine concentration; NIC-A, normalized iodine concentration in the aorta; NIC-V, normalized iodine concentration in the portal vein; PVT, portal vein thrombosis.

Figure 3

Box plot showing the range of Rho (A), Z (B), DEI (C), and K (D) for neoplastic and bland PVT on the portal phases. The Rho, Z, DEI, and K were significantly higher for neoplastic than for bland PVT on the portal phases. DEI, dual-energy index; K, spectral slope; PVT, portal vein thrombosis; Rho, electron density; Z, effective atomic number.

Figure 4

ROC curve analyses of DECT parameters for distinguishing neoplastic from bland PVT. DECT, dual-energy computed tomography; DEI, dual-energy index; IC, iodine concentration; K, spectral slope; NIC-A, normalized iodine concentration in the aorta; NIC-V, normalized iodine concentration in the portal vein; PVT, portal vein thrombosis; Rho, electron density; ROC, receiver operating characteristic; Z, effective atomic number.

Figure 5

A 57-year-old man with a bland PVT. (A) CT image at the portal phase shows a bland PVT in the main branch (arrow). (B) IC, NIC-A, and NIC-V of the lesion (arrow) was 0.40 mg/mL, 7.60%, 7.50% on the “Liver-Virtual Non-Contrast (Liver-VNC)” mode image. (C) Rho, Z, and DEI of the lesion (arrow) was 29.4 e⁻/cm³, 7.57, 0.001 on the “Rho/Z” mode image. (D) The calculated portal-phase K spectral curve value was 0.239. CT, computed tomography; DEI, dual-energy index; HU, Hounsfield units; IC, iodine concentration; K, spectral slope; NIC-A, normalized iodine concentration in the aorta; NIC-V, normalized iodine concentration in the portal vein; PVT, portal vein thrombosis; Rho, electron density; Z, effective atomic number.

Figure 6

A 42-year-old woman with a neoplastic PVT. (A) CT image at the portal phase shows a neoplastic PVT in the right portal vein (arrow) and a well-defined round mass in the right lobe of liver (circle). (B) IC, NIC-A, and NIC-V of the lesion (arrow) was 2.20 mg/mL, 32.7%, 27.4% on the “Liver-Virtual Non-Contrast (Liver-VNC)” mode image. (C) Rho, Z, and DEI of the lesion (arrow) was 37.1 e⁻/cm³, 8.77, 0.022 on the “Rho/Z” mode image. (D) The calculated portal-phase K spectral curve value was 2.567. CT, computed tomography; DEI, dual-energy index; HU, Hounsfield units; IC, iodine concentration; K, spectral slope; NIC-A, normalized iodine concentration in the aorta; NIC-V, normalized iodine concentration in the portal vein; PVT, portal vein thrombosis; Rho, electron density; Z, effective atomic number.

Figure 7

Nomogram for predicting PVTT patients. A nomogram (A) was constructed using NIC-V, Rho, and DEI. In both the training (B) and test (C) sets, the nomogram demonstrated good calibration. DCA was performed for the training (D) and test (E) sets. The x-axis shows the threshold probability and the y-axis represents the net benefit. ROC curves were used to evaluate and contrast the diagnostic performance of NIC-V, Rho, DEI, and the nomogram in the two sets (F, training sets; G, test sets). The AUCs of the nomogram were 0.994 and 0.940 in the training and test sets respectively. AUC, area under the curve; DCA, decision curve analysis; DEI, dual-energy index; NIC-V, normalized iodine concentration in the portal vein; PVTT, portal vein tumor thrombosis; Rho, electron density; ROC, receiver operating characteristic.