Accuracy of whole-body diffusion-weighted MRI (WB-DWI/MRI) in diagnosis, staging and follow-up of gastric cancer, in comparison to CT: a pilot study

Abstract

Background: Accurate staging of patients with gastric cancer is necessary for selection of the most appropriate and personalized therapy. Computed tomography (CT) is currently used as primary staging tool, being widely available with a relatively high accuracy for the detection of parenchymal metastases, but with low sensitivity for the detection of peritoneal metastases. Magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) has a very high contrast resolution, suggesting a higher diagnostic performance in the detection of small peritoneal lesions. The aim of this study was to retrospectively evaluate the added value of whole-body diffusion-weighted MRI (WB-DWI/MRI) to CT for detection of peritoneal carcinomatosis (PC) and distant metastases in the preoperative staging of gastric cancer.

Methods: This retrospective study included thirty-two patients with a suspicion of gastric cancer/recurrence, who underwent WB-DWI/MRI at 1.5 T, in addition to CT of thorax and abdomen. Images were evaluated by two experienced abdominal radiologists in consensus. Histopathology, laparoscopy and/or 1-year follow-up were used as reference standard.

Results: For overall tumour detection (n = 32), CT sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) was 83.3%, 100%, 100% and 82.4% respectively. For WB-DWI/MRI these values were 100%, 92.9%, 94.7% and 100%, respectively. For staging (n = 18) malignant lymph nodes and metastases, CT had a sensitivity, specificity/PPV/NPV of 50%/100%/100%/71.4%, and 15.4%/100%/100%/31.3% respectively. For WB-DWI/MRI, all values were 100%, for both malignant lymph nodes and metastases. WB-DWI/MRI was significantly better than CT in detecting tumour infiltration of the mesenteric root, serosal involvement of the small bowel and peritoneal metastases for which WB-DWI/MRI was correct in 100% of these cases, CT 0%.

Conclusions: WB-DWI/MRI is highly accurate for diagnosis, staging and follow-up of patients with suspected gastric cancer.

Keywords: Computed tomography (CT); Diffusion-weighted imaging (DWI); Magnetic resonance imaging (MRI); Neoplasm metastases; Neoplasm staging; Peritoneal neoplasms; Stomach neoplasm; WB-DWI/MRI.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1

A patient with an age-range between 60 and 70 years old was diagnosed with a primary gastric adenocarcinoma with signet ring cell differentiation, localized at the cardia. CT scan (a) showed the primary tumor (arrows) as well as hydronephrosis of the right kidney (*), without a demonstrable cause. He had a WB-DWI/MRI for operability assessment. The primary gastric cancer is well visualized on the axial b1000 DWI (b, arrow). Apart from a peritoneal tumor implant on the right distal ureter (arrows) as the cause for the hydronephrosis on the coronal (c) and axial b1000 DWI (d), a brain metastasis (arrowheads) was found in the left cerebellum on the axial post-contrast T1 image (e) as well as the b1000 DWI (f), since the brain is included in the WB-DWI/MRI

Fig. 2

A patient with an age-range between 70 and 80 years old was diagnosed with primary gastric cancer, for which an endoluminal stent was placed. CT scan in the axial plane (a) with coronal reconstruction (b) did not show any metastases. WB-DWI/MRI was performed for operability assessment, revealing an adenopathy in the gastro-hepatic fat (c, arrowhead), as well as peritoneal metastasis in the falciform ligament and on the surface of the left liver lobe (c–e, arrows)

Fig. 3

A patient with an age-range between 70 and 80 years old was diagnosed with primary gastric cancer. CT scan in the axial plane (a) with coronal reconstruction (b) did not show distant metastases. However, a slightly thickened anterior pararenal fascia on the left side (a, arrow) was noticed. WB-DWI/MRI was performed for further investigation with coronal (c) and axial b1000 (d) as well as contrast-enhanced T1-weighted images (e), and revealed –apart from the primary tumor (circled)– mesenteric tumor spread along the mesenteric root (c–e, arrows), as well as peritoneal tumor spread on the left anterior pararenal fascia (c, e, arrowheads)

Fig. 4

A patient with an age-range between 60 and 70 years old with a primary gastric cancer, where CT did not show any distant metastases (a, b), underwent a WB-DWI/MRI for operability assessment. Axial b1000 DWI images revealed millimetric tumor implants on the pancreatic surface (c, arrowheads). At the same time, multiple bone metastases (arrows) could be seen on the coronal b1000 DWI (d), coronal T2-weighted images (e), axial b1000 DWI (f) and post-contrast T1-weighted images (g)