RESULTS:

Successful TICs were recorded 159 out of 176 regions.Overall mean TPI were 38.9 � 12s (TA), 39.3 � 16.1s(TP), 38.4 � 13.3s (LN), and 37.6 � 7.5s (WM). Thecorresponding PI values in arbitrary units (AU) were14.5 � 3.5AU, 16.5 � 4.9AU, 13.6 � 4.4 AU and 8.4 �3.5 AU, respespectively. In cases with CT and/or MRIevidence of ischemic infarction, TICs showed prolonga-tion of the TPI by an average of 7.0 � 3.6s and reductionof PI by an average of 8.6 � 2.6 AU in the affected re-gions as compared to the unaffected hemisphere for allregions except for lacunar infarction where the valueswere similar.

CONCLUSION:

The combination of ultrasound contrast agents andcontrast specific imaging tools enable the sonographer toassess brain parenchymal perfusion semiquantitatively instroke patients. Perfusion abnormalities were character-ized by prolongation of the time to peak enhancement anda reduction in peak enhancement. Reliability has to beproven in a larger series.

Focal liver lesion characterization using lowacoustic power ultrasound imaging

Emilio Quaia, Elisa Mosconi, Francesca Degobbis,Roberto Pozzi Mucelli

Department of Radiology, Cattinara Hospital,University of Trieste, Italy

PURPOSE:

To determine if real-time low acoustic power imagingwith SonoVue (Bracco, Italy), a sulphur hexafluoride basedmicrobubble contrast agent, increases diagnostic performanceof baseline ultrasound (US) and color Doppler US (CDUS)when used to characterize focal liver lesions.

METHODS:

One-hundred and twenty focal hepatic lesions (37 hep-atocellular carcinomas (HCCs), 40 metastases, 21 heman-giomas, 7 focal nodular hyperplasias (FNHs), 6 macrore-generative nodules (RNNs), and 9 focal fatty sparing/changes (FFS/FFCs)) that were indeterminate on baseline

US were evaluated using US plus CDUS and contrastenhanced US performed at low acoustic power (mechani-cal index � 0.08–0.12). Imaging was performed after thebolus injection (2.4–4.8 ml) of SonoVue during the arte-rial (10–60 seconds), portal (60–90 seconds) and late(90–200 seconds from injection) phases. Two blindedobservers retrospectively expressed diagnostic confidence(from 1 to 5) about the malignant or benign nature ofeach lesion according to standard diagnostic criteria.

RESULTS:

Different contrast enhancement patterns were observedin HCCs (diffuse (n�34) or dotted (n�3) with progres-sive contrast washout) metastases (absent (n�20), periph-eral rim-like (n�15) or diffuse (n�5)), hemangiomas (pe-ripheral nodular with progressive fill-in (n�13), dotted(n�5) or with rapid fill-in (n�3)), FNHs (central in thefirst 2–5 seconds becoming diffuse in the following sec-onds), and RNNs and FFS/FFCs (persistent dotted). Area(Az) under the receiver operating characteristic curves(Az observer 1 / Az observer 2: 0.830 / 0.820 for baselineUS/CDUS and 0.930 / 0.960 for contrast-enhanced US)increased significantly (P� .05).

CONCLUSION:

Contrast-enhanced US with SonoVue increased diag-nostic performance of baseline US and CDUS in focalliver lesions characterization.

Use Of Contrast-Enhanced Ultrasonography ToMonitor Local Ablative Treatment Of Liver Cancer

Alberto Spinazzi, MD, Marc Engelhardt MDWW Medical Affairs, Bracco Diagnostics, Inc., Princeton, NJ

BACKGROUND:

While surgery remains the treatment of choice for pa-tients meeting criteria for resection, minimally invasivetreatments (MITs) are expanding, as the majority of livercancer patients have advanced disease or other complica-tions that make traditional surgical removal of their tu-mors impossible, and the results from MIT have exceededthose obtained with conventional chemotherapy or radia-tion. One of the most promising MITs is radiofrequency

BRIEF ABSTRACTS Academic Radiology, Vol 12, Suppl 1, May 2005

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