Defining vascular signatures of malignant hepatic masses: role of MDCT with 3D rendering

Extra-hepatic sarcoma metastasis surveillance in the liver: is arterial phase imaging necessary?

PURPOSE

To assess the value of arterial phase imaging (ART) in the detection of liver metastases on CT compared to portal venous phase imaging (PV) alone in patients with primary sarcomas.

METHODS

Multiphasic abdominal computed tomography (CT) images of patients with tissue-proven sarcomas were reviewed by five abdominal radiologists in a staggered fashion. Up to three of the largest or most conspicuous liver lesions were characterized on a four-point confidence level for PV independently, followed by PV + ART. Inter-observer reliability was evaluated with kappa statistics. Change in characterization of lesions by the addition of ART was calculated. Follow-up imaging was used to determine if index lesion characterization was valid.

RESULTS

55 of 149 patients had 470 liver lesion characterizations by the five readers with follow-up. Inter-observer agreement was κ = 0.62 on PV and κ = 0.58 on PV + ART. The intra-observer agreement between PV and ART interpretations of the same lesion was κ = 0.93. 426 lesion characterizations were possible on both PV and ART. Only 6 characterizations were changed after the addition of ART; 4 of the 6 changes were incorrect when compared to follow-up. Only 6 lesion characterizations could be made on ART alone (missed by PV), with all the malignant lesions arising from primary leiomyosarcomas. For the lesions seen on PV alone, the sensitivity, specificity, PPV, NPV, and accuracy were 98.8%, 100%, 100%, 99.3%, and 99.6%, respectively. After the addition of ART, they were 98.8%, 98.7%, 97.5%, 99.4%, and 98.7%, respectively.

CONCLUSION

ART adds marginal value to PV for characterization of metastatic liver lesions in patients with primary sarcomas, except possibly in primary leiomyosarcomas.

Diagnostic imaging of hepatic lymphoma

Hepatic lymphoma is a rare disease with poor prognosis because of delayed diagnosis. The disease comprises primary, metastatic, and intravascular hepatic lymphomas. The pathological characteristics of lymphomas differ contributing to difficulty in early diagnosis. Early diagnosis and appropriate treatment result in improved prognosis; therefore, diagnostic radiology and its development with various contrast agents are critical for improving disease outcomes. Herein, we review hepatic lymphomas and summarize the results of imaging studies in correlation with pathological characteristics. The information provided will help physicians in early diagnosis and thereby improving prognosis.

Grating-based phase-contrast imaging of tumor angiogenesis in lung metastases

Purpose

To assess the feasibility of the grating-based phase-contrast imaging (GPI) technique for studying tumor angiogenesis in nude BALB/c mice, without contrast agents.

Methods

We established lung metastatic models of human gastric cancer by injecting the moderately differentiated SGC-7901 gastric cancer cell line into the tail vein of nude mice. Samples were embedded in a 10% formalin suspension and dried before imaging. Grating-based X-ray phase-contrast images were obtained at the BL13W beamline of the Shanghai Synchrotron Radiation Facility (SSRF) and compared with histological sections.

Results

Without contrast agents, grating-based X-ray phase-contrast imaging still differentiated angiogenesis within metastatic tumors with high spatial resolution. Vessels, down to tens of microns, showed gray values that were distinctive from those of the surrounding tumors, which made them easily identifiable. The vessels depicted in the imaging study were similar to those identified on histopathology, both in size and shape.

Conclusions

Our preliminary study demonstrates that grating-based X-ray phase-contrast imaging has the potential to depict angiogenesis in lung metastases.