3D MDCT shows its worth in gastric cancer imaging

Volumetric visualization with multidetector-row CT helps find and characterize gastric cancer. It should also be used for the preoperative staging of these malignancies, according to studies presented Monday morning.

Korean researchers compared 2D and 3D MDCT for the preoperative staging of gastric cancer. They performed both noncontrast and contrast-enhanced CT scans in 106 patients who then underwent surgery. The researchers found that 3D outperformed axial studies in detection and preoperative staging of malignancy.

Gastric cancer detection rates for 2D and 3D MDCT were 87% and 98%, respectively. T-staging (primary tumor) overall accuracy rates for 3D and axial scanning were 92% and 77%, respectively.

Overall accuracy rates for N-staging (lymph node metastasis) were not significantly different: 62% for 2D and 64% for 3D. Three-D imaging surpassed 2D only for N-staging of advanced gastric cancer.

Multiplanar reconstruction and virtual endoscopy markedly improved staging of the primary tumor in gastric cancer, said Dr. H. Kim of Ulsan University's Alsan Medical Center in Seoul. For lymph node and distant metastasis staging, however, there were no significant differences between the two imaging methods.

Another Korean research team assessed MDCT gastroscopy in 162 patients with suspected gastric cancer. Using a four-slice CT scanner, they found CT gastroscopy reliable for the detection and characterization of malignancies.

The overall gastric cancer detection rate with MDCT was 91%. Detection rates for advanced and early gastric cancers were 97% and 84%, respectively. MDCT gastroscopy characterized 94% of advanced gastric cancers and 72% of early gastric cancers.

MDCT gastroscopy provided excellent results in detection and characterization of gastric cancer in most patients suspected of the disease, said principal investigator Dr. Eung Young Ko of Hallym University Hospital in Seoul. MDCT was limited, however, in the detection and characterization of early gastric cancer.

A Japanese research group studied MDCT's role in the evaluation of gastric cancer's depth of invasion. They performed volumetric analysis in 41 patients who underwent scanning after drinking 600 mL of water and receiving a 100-mL nonionic contrast agent injection. The researchers found that MDCT was an accurate tool for the assessment of serosal invasion in gastric cancer.

MDCT's overall sensitivity, specificity, and accuracy rates in determining the invasion of serosa were, respectively, 85%, 96%, and 92%, as established by two radiologists blinded to each other's readings.

MDCT does not require additional time or cost compared with the standard technique, said Dr. S. Kumano, a radiologist at Osaka University Graduate School of Medicine. He recommends its use for staging all cases of gastric cancer.

But Dr. Borut Marincek, radiology chair at University Hospital Zurich in Switzerland, said that the value of 3D in gastric cancer is open for discussion.

Until now, no studies have addressed 3D MDCT's role in gastric cancer. While this condition is more prevalent in the Far East -- particularly in Japan -- than in Europe or the U.S., the accumulation of data could bring implications for patients affected by the disease all over the world, Marincek said.