An application study of CT perfusion imaging in assessing metastatic involvement of perigastric lymph nodes in patients with T1 gastric cancer

Value of multiphase contrast-enhanced CT with three-dimensional reconstruction in detecting depth of infiltration, lymph node metastasis, and extramural vascular invasion of gastric cancer

Background

Multiphase contrast-enhanced computed tomography (CECT) can reveal the location, morphology, size, and enhancement pattern of gastric cancer (GC), whereas the three-dimensional reconstruction (3DR) technique can better display the relationships of the lesions with surrounding structures, the feeding vessels, and lymph node metastasis. Here, we investigated the value of multi-phase CECT with 3DR in detecting depth of infiltration, lymph node metastasis, and extramural vascular invasion (EMVI) of GC.

Methods

The clinical and imaging data of 132 GC patients admitted to the Chongqing Hospital of Traditional Chinese Medicine and the Third Affiliated Hospital of Chongqing Medical University during the period from January 2012 to October 2019 were collected. All patients received plain and multiphase contrast-enhanced CT scans. The agreement between the results of preoperative CT evaluation and the surgical/pathological findings was compared.

Results

(I) CT findings of GC of 3 differentiation levels: on the multiphase CECT, the peak enhancement percentage was highest in the portal venous phase. The CT values significantly differed among the arterial, portal venous, and equilibrium phases (P<0.05); the differences in the arterial, portal venous, and equilibrium phases were statistically significant among the well-, moderately, and poorly differentiated groups (all P<0.05); finally, the difference in the equilibrium phase was statistically significant between the well- and moderately differentiated groups (P<0.05). (II) Preoperative CT and postoperative pathology had good consistency in T staging (Kappa =0.667). (III) The Kappa values between the preoperative CT-diagnosed lymph node metastasis and postoperative pathologically showing an increasing consistency with the increase of CT enhancement differences. (IV) Preoperative CT and postoperative pathology had good consistency in N staging (Kappa =0.779). (V) Preoperative CT in displaying arterial supply to the stomach. The rate of positive EMVI was 32.6% (43/132) on preoperative CT. The positive EMVI diagnosed by preoperative CT was correlated with tumor size, growth pattern, tissue differentiation degree, T stage, and N stage (all P<0.05).

Conclusions

Multiphase CECT combined with 3DR has high diagnostic performance in detecting the depth of infiltration, lymph node metastasis, and EMVI of GC.

Diagnostic performance of dynamic volume perfusion CT for differentiation of head and neck cancer from healthy tissue and post-therapeutic changes

BACKGROUND

Post-therapeutic tissue is bradytrophic and thus has low perfusion values in PCT. In contrast, malignant tissue is expected to show higher perfusion values as cancer growth partially depends on angiogenesis.

OBJECTIVES

This prospective study investigates perfusion computed tomography (PCT) for the post-therapeutic detection of cancer in the head and neck region.

METHODS

85 patients underwent PCT for 1) initial work-up of head and neck cancer (HNC; n=22) or 2) for follow-up (n=63). Regions of interest (ROIs) were placed in confirmed tumour, a corresponding location of benign tissue, and reference tissue. Perfusion was calculated using a single input maximum slope algorithm. Statistical analysis was performed with the Mann-Whitney U-test.

RESULTS

PCT allowed significant differentiation of malignant tissue from post-therapeutic tissue after treatment for HNC (p=0.018). Significance was even greater after normalization of perfusion values (p=0.007). PCT allowed highly significant differentiation of HNC from reference tissue (p<0.001).

CONCLUSIONS

PCT provides significantly distinct perfusion values for malignant and benign as well as post-therapeutically altered tissue in the head and neck area, thus allowing differentiation of cancer from healthy tissue. Our results show that PCT in conjunction with a standard algorithm is a potentially powerful HNC diagnostic tool.