Identification of residual tumor with intraoperative contrast-enhanced ultrasound during glioblastoma resection

Objective: The purpose of this study was to assess the capability of contrast-enhanced ultrasound (CEUS) to identify residual tumor mass during glioblastoma multiforme (GBM) surgery, to increase the extent of resection. Methods: The authors prospectively evaluated 10 patients who underwent surgery for GBM removal with navigated ultrasound guidance. Navigated B-mode and CEUS were performed prior to resection, during resection, and after complete tumor resection. Areas suspected for residual tumors on B-mode and CEUS studies were localized within the surgical field with navigated ultrasound and samples were sent separately for histopathological analysis to confirm tumor presence. Results: In all cases tumor remnants were visualized as hyperechoic areas on B-mode, highlighted as CEUS-positive areas, and confirmed as tumoral areas on histopathological analysis. In 1 case only, CEUS partially failed to demonstrate residual tumor because the residual hyperechoic area was devascularized prior to ultrasound contrast agent injection. In all cases CEUS enhanced B-mode findings. Conclusions: As has already been shown in other neoplastic lesions in other organs, CEUS is extremely specific in the identification of residual tumor. The ability of CEUS to distinguish between tumor and artifacts or normal brain on B-mode is based on its capacity to show the vascularization degree and not the echogenicity of the tissues. Therefore, CEUS can play a decisive role in the process of maximizing GBM resection

Pulse inversion US with echographic contrast media (Levovist®) in the evaluation of hepatic metastases

Purpose. To evaluate if Pulse Inversion Harmonic Imaging with contrast agent injection (Levovist) is able to determine an increase of echogenicity in normal hepatic parenchyma, and to compare its capability to detect metastatic focal lesions with that of standard US and spiral CT. To define and standardize the technical and methodological aspects of this new technique. Material and methods. A selected group of 72 patients (42 males and 30 females) with clinical and instrumental suspect of hepatic metastatic lesions was included in the prospective study. Each patient was examined by conventional ultrasound (US), Pulse Inversion Harmonic Imaging (PI) and spiral-CT (spCT). US examination was performed using an HDI 5000 (ATL, Bothell, USA) equipped with a broadband probe (5,0-2,0 MHz). 2.5 g Levovist® (Schering AG-Berlin) was administered intravenously, at concentration of 300 mg/ml and a flow rate of 7 ml/min. Video clips obtained with the acquired images before and after contrast medium administration were transferred to a magnet optic disk unit. Examinations were evaluated by an experienced radiologist blindly on a workstation that allowed a qualitative-quantitative analysis. SpCT images were evaluated separately by another experienced radiologist. US images were evaluated qualitatively (number of lesions, site of lesion, diameter of the smallest lesion detectable) and quantitatively (increase in parenchymal echogenicity 20″, 40″, 60″ and 5′ after the injection of contrast agent). Results. In all cases examined, the echogenicity of normal hepatic parenchyma increased after contrast agent administration, reaching a peak of about 250% (1DS) at 60 s and decreasing gradually in 5 minutes. Conventional US detected 195 focal lesions, CT 231, and US with pulse inversion technique and contrast agent (US-PI) 287. Mean differences among the number of lesions detected by the different techniques per each patient were also calculated. Wilcoxon Signed Rank Test showed a statistically significant difference between US-PI and US (p<.0001), CT and US (p=.0052) and US-PI and CT (p=.0121). US-PI detected the smallest lesions, which went undetected by the CT and conventional US examinations. Discussion and conclusions. In 10 cases (14.3%) contrast enhanced US-PI demonstrated the presence of a number of lesions greater than 5 (diffuse metastatization and inoperability) in comparison to that detected by spCT). The greater echogenicity of normal hepatic parenchyma using pulse inversion technique after Levovist infusion allowed to better demonstrate hepatic metastases. This technique showed a higher identification rate of small lesions in comparison to basal examination and to spiral CT. Contrast enhanced US-PI demonstrated a remarkable increase in echogenicity of hepatic parenchyma in portal phase. The technique significantly improves the detection of focal lesions allowing visualization of smaller lesions compared to CT and US. These results indicate that the technique could be used in the staging of liver metastasis. However, large multicentric trials are required to validate US-PI and better define its role in the work-up of patients with neoplastic disorder

Value of contrast-enhanced ultrasonography for detecting renal infarcts proven by contrast enhanced CT. A feasibility study

The effectiveness of contrast- enhanced ultrasonography (CEUS) in the evaluation of patients with acute renal infarcts was investigated, using contrast-enhanced helical computed tomography (CT) as the reference imaging procedure. Twentyseven consecutive patients with acute renal infarcts detected with contrast enhanced helical CT underwent CEUS. Digital cine-clips of CEUS were evaluated by two independent readers blinded to CT findings. Image quality was rated subjectively on a four-point scale. Then, readers were asked to assign a confidence level in diagnosis of renal infarct at the upper pole, medium portion, and lower pole of each kidney according to a five degree scale, ranging from definitely absent to definitely present. ROC curve analysis was employed to assess the overall confidence of diagnosis of infarct, and weighted kappa values were calculated to assess inter-reader agreement. The subjective image quality of CEUS was lower than the image quality of CTat the upper poles. However, the diagnostic performance of CEUS was excellent (area under receiver-operator characteristic curve 0.992\ub10.006 for reader 1; 0.991\ub1 0.007 for reader 2), with very good inter-reader agreement (weighted kappa value=0.83). CEUS is a reproducible tool to detect acute renal infarcts in men, with a diagnostic performance approaching that of CT