Can low-dose CT perfusion imaging accurately assess response of advanced gastric cancer with neoadjuvant chemotherapy?

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

OBJECTIVE

To assess metastatic involvement of perigastric lymph nodes (PLNs) in patients with T1 gastric cancer by using CT perfusion imaging (CTPI).

METHODS

A total of 82 annotated PLNs of 33 patients with T1 gastric cancer confirmed by endoscopic ultrasonography underwent CTPI and portal phase CT scan before operation. The scan data were post-processed to acquire perfusion maps and calculate perfusion parameters including blood flow (BF) and permeability surface (PS). A radiologist measured the short axis diameters and perfusion parameters of PLNs. According to the post-operative pathology result, PLNs were divided into two groups: metastatic and inflammatory LNs. Perfusion parameters values and the size of PLNs between two groups were respectively compared statistically by t-test, and a receiver operating characteristic curve analysis was used to determine the optimal diagnostic cut-off value with sensitivity, specificity and area under the curve.

RESULTS

Examined 82 PLNs were metastatic in 45 (54.9%) and inflammatory in 37 (45.1%). The mean values of perfusion parameters and the short axis diameters in metastatic and inflammatory PLNs, respectively, were BF of 97.48 vs 81.21 ml/100 mg /min (p < 0.001), PS of 45.11 vs 36.80 ml/100 mg /min (p < 0.001), and the size of 1.51 cm vs 1.29 cm (p = 0.059). The sensitivity of 84.4%, specificity of 67.6% and area under the curve of 0.826 for BF with cut-off value of 88.89 ml/100 mg /min for differentiating metastatic from inflammatory nodes were higher than those of PS or the size of PLNs (p < 0.001).

CONCLUSION

CT perfusion parameters values were different between metastatic and inflammatory PLNs in T1 gastric cancer. BF value may be the most reliable diagnostic marker of metastatic PLNs, and it is helpful for clinicians to choose treatment modality or management plan in T1 gastric cancer patients.

ADVANCES IN KNOWLEDGE

CTPI gives information on vascularization of LNs.BF value might be a more effective marker than PS or the size of LNs for differentiating metastatic from inflammatory LNs in patients with T1 gastric cancer.

An application study of low-dose computed tomography perfusion imaging (LDCTPI) in breast cancer and breast fibroadenoma

PURPOSE

To explore the characteristics of breast cancer and breast fibroadenoma using low-dose computed tomography perfusion imaging (LDCTPI) including specific perfusion parameter values, and seek the potential clinical applications in cancer prognosis assessment.

MATERIALS AND METHODS

Fifty patients including 30 diagnosed with breast cancer and 20 with breast fibroadenoma, as well as 15 control subjects with normal breasts were studied prospectively using LDCTPI examinations. The acquired volumetric imaging data were used for calculation, mapping and analysis by using a body tumor perfusion protocol in the CT perfusion software to measure 4 parameters: blood flow (BF), blood volume (BV), mean transit time (MTT), and the permeability surface (PS) area product. Statistical data analysis was then performed to distinguish the difference of the 4 parameter values among normal control, breast cancer and breast fibroadenoma cases.

RESULTS

The mean perfusion values of 15 normal controls were as follows: BF, 20.03±4.08 mL/100 g/min; BV, 4.53±0.95 mL/100 g; MTT, 5.90±0.82 s; and PS, 9.25±1.18 mL/100 g/min. The mean perfusion values of 30 cancer patients were as follows: BF, 56.67±6.59 mL/100 g/min; BV, 5.82±0.68 mL/100 g; MTT, 6.01±0.82 s; and PS, 24.95±5.05 mL/100 g/min. The mean perfusion values of 20 patients with breast fibroadenoma were as follows: BF, 46.24±6.65 mL/100 g/min; BV, 5.07±0.73 mL/100 g; MTT, 7.51±0.62 s; and PS, 16.73±6.48 mL/100 g/min. Comparing the 3 groups, differences were all statistically significant for BF, BV, MTT and PS values (p < 0.05, respectively); The BF, BV, PS values were highest in group of cancer patients, while the MTT value was highest in group of patients diagnosed with breast fibroadenoma.

CONCLUSION

Breast CT perfusion imaging is a promising functional imaging technology in breast cancer diagnosis, which can provide valuable quantitative imaging markers to assist evaluation of breast tumors.