High-Resolution Ultrasound Including Contrast-Enhanced Ultrasound (CEUS) for the Detection of Gas Formation during Aspergillus Fumigatus Infection in Mice.
OBJECTIVE
A. fumigatus infections represent a major threat for patients with a suppressed immune system. Early diagnosis is of importance for a favorable outcome but appears to be difficult due to limited diagnostic procedures. Here we investigated the sensitivity of high-resolution ultrasound (HRU) for the detection of A. fumigatus infection in the liver.


METHODS
BALB/c mice were intravenously infected with A. fumigatus and monitored by HRU, Doppler sonography (CCDS), contrast-enhanced ultrasound (CEUS), and real-time strain color-coded elastography (CCE) using a multi-frequency probe (6 - 15 MHz). Contrast media bolus injection of sulfur-hexafluoride micro-bubbles was applied and digital cine-loops from the arterial phase, as well as the portal venous phase up to the late phase of the whole liver were analyzed. All data were correlated to the histopathological findings.


RESULTS
Using HRU and CEUS, a sonic shadow was detected in all infected animals. All Aspergillus-infected nodes from 3 - 6 mm in the liver showed a shadow with rim enhancement and no intranodal enhancement when using CEUS. A. fumigatus infection was confirmed by CFU assessment and histopathological analysis. Granulomas were not associated with shadowing on B-mode. In contrast, granulomas with a diameter above 5 mm and a higher stiffness in CCE generated particularly an arterial rim enhancement and portal venous washout without contrast media uptake in the late phase. In addition, CEUS was able to define dynamic capillary microvascularization of infected liver areas.


CONCLUSIONS
Liver lesions associated with A. fumigatus infection can be detected in mice when combined with CEUS and CCE in vivo.
Institute of Immunology, University of Regensburg, Germany.
B
B
Echtenacher
Department of Gynecology and Obstetrics, University Hospital Regensburg, Germany.
A K
AK
Wege
Institute of Pathology, University of Regensburg, Germany.
K
K
Schardt
Department of Gynecology and Obstetrics, University Hospital Regensburg, Germany.
F
F
Bitterer
Orthopaedic Department, University Hospital Basel, Suisse.
S
S
Gehmert
Clinic of Internal Medicine III, University Hospital Regensburg, Germany.
P
P
Hoffmann
Institute of Radiology, University Hospital Regensburg, Germany.
C
C
Stroszczynski
Institute of Radiology, University Hospital Regensburg, Germany.
E M
EM
Jung
D000818:Animals; D001228:Aspergillosis / Q000000981:diagnostic imaging* / Q000473:pathology; D001232:Aspergillus fumigatus; D003287:Contrast Media; D054459:Elasticity Imaging Techniques; D005740:Gases; D007089:Image Enhancement; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008107:Liver Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D051379:Mice; D012016:Reference Values
D003287:Contrast Media; D005740:Gases