Characterization of focal liver lesions with SonoVue-enhanced sonography: international multicenter-study in comparison to CT and MRI.

AIM: To evaluate in a multicenter study whether the sonographic characterization of focal liver lesions can be improved using SonoVue-enhancement; and to compare this method with computed tomography (CT) and magnetic resonance imaging (MRI). METHODS: One hundred and thirty four patients with one focal liver lesion detected in baseline ultrasound (US) were examined with conventional US, contrast-enhanced US (n = 134), contrast-enhanced CT (n = 115) and/or dynamic contrast-enhanced MRI (n = 70). The lesions were classified as malignant, benign or indeterminate and the type of lesion was determined. The final diagnosis based on the combined information of all imaging examinations, clinical information and histology (n = 32) was used. Comparisons were made to see whether the addition of contrast-enhanced US led to the improvement of the characterization of doubtful focal liver lesions. RESULTS: In comparison with unenhanced US, SonoVue markedly improves sensitivity and specificity for the characterization (malignant/benign) of focal liver lesions. In comparison with CT and/or dynamic MRI, SonoVue-enhanced sonography applied for characterization of focal liver lesions was 30.2% more sensitive in the recognition of malignancy and 16.1% more specific in the exclusion of malignancy and overall 22.9% more accurate. In the subgroup with confirmative histology available (n = 30), sensitivity was 95.5% (CEUS), 72.2% (CT) and 81.8% (MRI), and specificity was 75.0% (CEUS), 37.5% (CT) and 42.9% (MRI). The sensitivity and specificity of CEUS for the identification of focal nodular hyperplasia (FNH) and hemangiomas was 100% and 87%, resulting in an accuracy of 94.5%. CONCLUSION: SonoVue-enhanced sonography emerges as the most sensitive, most specific and thus most accurate imaging modality for the characterization of focal liver lesions.

Cecal pneumatosis in patients with obstructive colon cancer: correlation of CT findings with bowel viability.

OBJECTIVE: The purpose of our study was to reassess CT findings of cecal pneumatosis in patients with acute large-bowel obstruction due to colon cancer to determine whether this condition indicates transmural necrosis versus viable bowel and also whether other CT findings could be used to identify patients with transmural necrosis. CONCLUSION: CT findings of cecal pneumatosis do not always indicate transmural infarction in patients with acute large-bowel obstruction due to colon cancer. Cecal pneumatosis may be related to viable bowel when it displays a bubblelike pattern or when it is not associated with other findings of ischemia.

Flow-independent magnetic resonance venography of the calf.

PURPOSE: To show that flow-independent venography that exploit the intrinsic MR properties of blood to isolate vessels from surrounding structures can be used for depiction of peripheral veins and for detection of deep venous thrombosis (DVT). MATERIALS AND METHODS: Sequence and parameters were first determined on a theoretical basis. The sequence was then optimized in volunteers (N = 4) for the depiction of the peripheral venous vessels. Qualitative evaluation of the normal venous anatomy was performed in five volunteers. The feasibility of diagnosing DVT of the calf with this method was evaluated with preliminary clinical studies. RESULTS: Excellent depiction of the venous anatomy was achieved in all volunteers with the optimized technique. Very small venous structures, such as superficial, muscular, and perforator veins, were clearly depicted because of the high spatial and contrast resolution capacities of the sequences. In all six patients, DVT findings diagnosed by duplex sonography were also seen on MR venography. CONCLUSION: Venous anatomy mapping and detection of lower-limb DVT appear feasible using flow-independent MR venograms.

Appendicitis: evaluation of sensitivity, specificity, and predictive values of US, Doppler US, and laboratory findings.

PURPOSE: To evaluate the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of ultrasonography (US), Doppler US, and laboratory findings in the diagnosis of appendicitis. MATERIALS AND METHODS: A total of 125 consecutive patients suspected of having appendicitis were prospectively included for US appendiceal (diameter enlarged to 6 mm or greater, intraluminal fluid, lack of compressibility) and periappendiceal (periileal inflammatory changes, cecal wall thickening, periileal lymph nodes, peritoneal fluid) evaluation, Doppler US evaluation (appendiceal wall signal), and laboratory assessment (leukocytosis, C-reactive protein [CRP]). Definite diagnoses were established at surgery in 61 patients, at endoscopy with biopsy in two patients, and at clinical follow-up in 62 patients. RESULTS: The prevalence of appendicitis was 46%. The appendix was identified with US in 86% of the patients, which included 96% of patients with and 72% of patients without appendicitis. The most accurate appendiceal finding for appendicitis was a diameter of 6 mm or larger, with a sensitivity, specificity, NPV, and PPV of 98%. The lack of visualization of the appendix with US had an NPV of 90%. The most accurate periappendiceal finding of appendicitis was the presence of inflammatory fat changes, with an NPV of 91% and a PPV of 76%, whereas other findings had both NPV and PPV less than 65%. An increase in both white blood cell (WBC) count and CRP level had a PPV of 71%, whereas combined normal WBC count and CRP value had an NPV of 84%. CONCLUSION: A threshold 6-mm diameter of the appendix under compression is the most accurate US finding for appendicitis and has high NPV and PPV.