Intracavitary contrast-enhanced ultrasound in abscess drainage--feasibility and clinical value.

OBJECTIVE: To evaluate the usefulness of intracavitary-applied contrast-enhanced ultrasound (ICCEUS) with BR1 in ultrasound-guided puncture and drainage of abdominal and pelvic abscesses. MATERIAL AND METHODS: A total of 71 consecutive patients received ICCEUS after placement of a drainage catheter or a needle in abdominal or pelvic abscesses. Portions of 0.1 ml of BR1 and 20 ml of saline were injected through the drainage catheter or needle. Ultrasound recordings were evaluated to answer the following questions: correct placement of the catheter by showing enhancement in the cavity and the drain - ICCEUS findings suggesting incomplete enhancement in all abscess cavities - enhancement in non-abscess structures. RESULTS: About 52% of patients had liver, 14% of patients had intraperitoneal, 11% had subphrenic, 14% had retroperitoneal, 6% had splenic, and 4% had pelvic abscesses. The majority of the patients received drain placement with 10-F using trocar technique. Enhancement in the drain or needle was seen in all patients. In 2% of patients, during the initial approach, a dislodgment of the catheter from the abscess cavity was diagnosed. Due to non-enhancing abscess compartments, in 36% of the patients more than one drainage treatment was necessary at the time of the first approach. In 14% of the patients communication with surrounding structures was diagnosed. Additional treatment resulted in 4% of cases. CONCLUSION: ICCEUS was helpful in all patients to confirm correct placement of drain or puncture needle. In 40% of patients, as a consequence of ICCEUS, additional therapy was scheduled, either additional drainage or abscess puncture, endoscopic retrograde drainage of the biliary or pancreatic duct or thoracic intervention.

Endorectal fusion imaging: A description of a new technique.

BACKGROUND: Fusion imaging is an accepted method in abdominal imaging allowing a simultaneous display of reference imaging with a live ultrasound (US) investigation. For prostate cancer, promising results have been published for endorectal US (ERUS)-guided biopsy of suspicious lesions in magnetic resonance imaging (MRI). To our knowledge, no other indication for the fusion of ERUS with MRI has been reported so far. METHODS: We report on three patients scheduled for ERUS due to anorectal fistulae after treatment (n = 2) or rectal carcinoma (n = 1), which were scheduled for real-time virtual onography (RVS), a method for the fusion of MRI imaging with US. RESULTS: In all patients, RVS was successful. The course of the fistulae could be defined and the success of the treatment could be confirmed. In the patient with rectal carcinoma, the lymph nodes suspicious in MRI could be identified. CONCLUSIONS: MRI/ERUS fusion has the potential for follow-up of anorectal fistulae and abscesses, and staging of anal and rectal tumors.

Contrast-enhanced (endoscopic) ultrasound and endoscopic ultrasound elastography in gastrointestinal stromal tumors.

BACKGROUND AND OBJECTIVES: Gastrointestinal stromal tumors (GISTs) represent the largest group of subepithelial tumors (SET) of the upper gastrointestinal (GI) tract. They may show malignant behavior, in contrast to other SET. Endoscopic ultrasound (EUS) is frequently used to characterize SET. With the introduction of contrast-enhanced ultrasound (CEUS) into EUS (CE-EUS), distinct enhancement patterns can be detected. In the presented study, the characteristic features of CE-EUS in GIST are analyzed and compared with those of other SET. MATERIALS AND METHODS: Consecutive patients from four centers with SET of the upper and middle GI tract were included and received endoscopic or transcutaneous CEUS. The results were compared with EUS-guided tissue acquisition, forceps biopsy, or surgical resection. RESULTS: Forty-two out of 62 (68%) patients had SET of the stomach, 17/62 (27%) of the small intestine, 2/62 (3%) of the esophagus, and 1/62 (2%) extraintestinal. Eighty-one percent underwent surgery. Leiomyoma was found in 5/62 (8%) and GIST in 57/62 patients (92%). Thirty-nine out of 57 (68%) patients had GIST lesions in the stomach, 17/57 (30%) had GIST of the small intestine, and 1/57 (2%) patients had extraintestinal GISTs. GIST size was 62.6 ± 42.1 (16-200) mm. Hyperenhancement had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 98%, 100%, 100%, 93%, and 98% for the diagnosis of GIST. Fifty out of 57 patients with GIST (88%) showed avascular areas in the center of the lesions. CONCLUSION: CE-EUS and CEUS show hyperenhancement and avascular areas in a high percentage of GIST but not in leiomyoma. Thus, GIST and leiomyoma can be discriminated accurately.

Ultrasound contrast agents.

Endoscopic ultrasound (EUS) plays an important role in imaging of the mediastinum and abdominal organs. Since the introduction of US contrast agents (UCA) for transabdominal US, attempts have been made to apply contrast-enhanced US techniques also to EUS. Since 2003, specific contrast-enhanced imaging was possible using EUS. Important studies have been published regarding contrast-enhanced EUS and the characterization of focal pancreatic lesions, lymph nodes, and subepithelial tumors. In this manuscript, we describe the relevant UCA, their application, and specific image acquisition as well as the principles of image tissue characterization using contrast-enhanced EUS. Safety issues, potential future developments, and EUS-specific issues are reviewed.

Percutaneous biopsies of splenic lesions--a clinical and contrast enhanced ultrasound based algorithm.

OBJECTIVE: Splenic lesions are rare and characterization is difficult. Secondary spread is more frequent than primary malignant lesions. Thus clinical circumstances are important in the general work-up. Contrast enhanced ultrasound (CEUS) had high accuracy in recent studies but the positive predictive value is low. Biopsy is considered dangerous. Recent studies have brought back this method into focus showing an excellent efficacy and safety. The aim of this study was to estimate the rate of relevant biopsy results in patients with splenic lesions concerning the clinical circumstances. DESIGN: Patients with unclear splenic lesions which appeared progressively hypoenhancing in the late phase of CEUS with BR1 were included. Biopsy was performed with ultrasound guidance. Patients were sorted into 5 groups according to their clinical symptoms. RESULTS: 44 patients were enrolled, 59% had benign lesions. 73% were rated relevant. For the subgroups the rate was: patients with hints for hemato-oncological diseases 83%, patients without symptoms 38%, patients with infections of unknown origin 100%, patients with suspicion of metastases 33%, immunocompromised patients 100%. One bleeding could be managed conservatively, another bleeding was detected incidentally 2 weeks later. CONCLUSION: Percutaneous biopsy of unclear splenic lesions which appear hypoenhancing in the late phase of CEUS with BR1 results in a high rate of relevant lesions. The results should be tested in larger numbers of patients.

Contrast enhanced ultrasound of renal masses.

Contrast enhanced ultrasound (CEUS) has gained clinical importance over the last years for the characterization of hepatic masses. Its role in extrahepatic indications has been investigated repeatedly but has been less comprehensively studied. Currently more than 50% of renal masses are incidentally diagnosed, mostly by B-mode ultrasound. The method of choice for characterization of renal lesions is contrast enhanced computed tomography (CECT). In the case of cystic lesions CECT refers to the Bosniak classification for cystic lesions to assess the risk of malignant behavior. The majority of masses are renal cell carcinoma, but the exact proportion is controversial. Disadvantages of CECT are a significant risk for patients with impaired renal function, allergic reactions and hyperthyroidism due to iodinated contrast agents. Several studies concerning CEUS for the characterization of both solid and cystic renal lesions have been published, but prospective multicenter studies are missing, the presented data being mainly descriptive. The aim of the this manuscript is to review the current literature for CEUS in renal masses, to summarize the available data and focus on possible concepts for studies in the future.

Quantitative contrast enhanced ultrasound of the liver for time intensity curves-Reliability and potential sources of errors.

INTRODUCTION: Time intensity curves for real-time contrast enhanced low MI ultrasound is a promising technique since it adds objective data to the more subjective conventional contrast enhanced technique. Current developments showed that the amount of uptake in modern targeted therapy strategies correlates with therapy response. Nevertheless no basic research has been done concerning the reliability and validity of the method. PATIENTS AND METHODS: Videos sequences of 31 consecutive patients for at least 60s were recorded. Parameters analysed: area under the curve, maximum intensity, mean transit time, perfusion index, time to peak, rise time. The influence of depth, lateral shift as well as size and shape of the region of interest was analysed. RESULTS: The parameters time to peak and rise time showed a good stability in different depths. Overall there was a variation >50% for all other parameters. Mean transit time, time to peak and rise time were stable from 3 to 10cm depths, whereas all other parameters showed only satisfying results at 4-6cm. Time to peak and rise time were stable as well against lateral shifting whereas all other parameters had again variations over 50%. Size and shape of the region of interest did not influence the results. DISCUSSION: (1) It is important to compare regions of interest, e.g. in a tumour vs. representative parenchyma in the same depths. (2) Time intensity curves should not be analysed in a depth of less than 4cm. (3) The parameters area under the curve, perfusion index and maximum intensity should not be analysed in a depth more than 6cm. (4) Size and shape of a region of interest in liver parenchyma do not affect time intensity curves.

The value of contrast enhanced ultrasound (CEUS) in the characterisation of patients with renal masses.

Renal masses are frequently incidentally found on ultrasound. Contrast enhanced computed tomography (CECT) is regarded as the method of choice. Contrast enhanced ultrasound (CEUS) has a high impact for characterisation of hepatic lesions. Its use in renal masses has been less comprehensively studied. Two hundred and one patients referred for surgical treatment of a renal mass, 143 patients fulfilling inclusion criteria (histology and reference method). Baseline ultrasound and CEUS with BR1, histology obtained by surgery (89%) or biopsy (11%). Eighty-eight percent of the patients had renal lesions which were malignant and 12% benign lesions. Eighty percent had renal cell carcinoma (RCC). Seven percent of the lesions were cystic. Two patients were upgraded by CEUS from CECT Bosniak II into CEUS Bosniak III resp. IV. CEUS could predict malignancy with a sensitivity, specificity, positive, negative predictive value and accuracy in 97%, 45%, 91%, 75%, and 90%. The correct staging was diagnosed by CEUS (CECT) in 83% (69%). CEUS was superior to CECT in the staging and characterisation of RCC, also in the subgroup of patients with cystic lesions. CEUS can replace CECT e.g. in patients with allergies or contraindications against CECT. Multicentre studies are necessary to confirm the findings.

Contrast-enhanced ultrasound of histologically proven liver hemangiomas.

UNLABELLED: Differentiation of small and atypical hemangiomas from other hepatic masses using imaging methods can be difficult, especially in patients with underlying malignant disease. Therefore, contrast-enhanced ultrasound was assessed in patients with histologically confirmed hemangiomas with respect to contrast-enhancing kinetics and tumor characteristics. In 58 patients with indeterminate hepatic lesions demonstrated with at least 2 imaging methods (ultrasound/computed tomography/magnetic resonance imaging), ultrasound-guided liver biopsy revealed hemangioma. In all patients a hepatic neoplasm had been suspected because of underlying malignant disease (n=41), liver cirrhosis (n=15), or growth of the lesion (n=2). All patients underwent nonlinear, low mechanical index real-time contrast-enhanced ultrasound scanning with bolus injections of SonoVue. Peripheral nodular arterial enhancement was detected in 43 patients (74%), whereas the typical metastatic peripheral rim-like enhancement was not observed at all. Strong homogenous arterial enhancement was found in 9 of 58 (16%) patients. In 6 patients (10%), the arterial contrast enhancement pattern could not be determined because of the very small size of the lesions or fibrotic nodules. Forty-five (78%) of the hemangiomas showed homogenous centripetal filling within 180 seconds. CONCLUSION: Contrast-enhanced ultrasound demonstrates typical hemangioma imaging characteristics, that is, peripheral nodular contrast enhancement and iris-diaphragm sign in a high percentage of patients with undetermined lesions. This technique may therefore improve noninvasive functional characterization and differentiation of hemangiomas.

Analysis of neuroendocrine tumour metastases in the liver using contrast enhanced ultrasonography.

BACKGROUND: Imaging of liver tumours might be improved by contrast-enhanced ultrasonography, which allows much better demonstration of the microvascular system. The aim of this study was to assess the sonographic morphology and vascularity of neuroendocrine liver metastases. METHODS: Forty-eight patients with histologically proven neuroendocrine tumours (NET) and suspected liver metastases--as well as 50 consecutive patients with liver metastases of other origins--were included in a prospective study to evaluate tumour characteristics using B-mode, colour Doppler (CDI) and contrast-enhanced ultrasound (CEUS). RESULTS: In 4/48 patients with NET, liver biopsy revealed hemangiomas. The typical B-mode appearance was that of both echo-rich and echo-poor combined, also inhomogeneous depending on the size, and often centrally cystic. With CDI, neuroendocrine metastases appeared hypervascular (66%) or isovascular (34%). Metastases of another origin were hypovascular in 82%. With CEUS, neuroendocrine metastases showed increased arterial enhancement in 38 patients and hypoechoic appearance in the portalvenous phase in 39 patients. In liver metastases of another origin, the sensitivity for malignancy due to a hypoechoic appearance during the portalvenous phase was 100%. In liver metastases of NET origin the sensitivity for malignancy was 39/48 (82%). CONCLUSIONS: Neuroendocrine tumour metastases might show characteristics which are similar to hemangiomas. In patients with liver cirrhosis and severe fatty liver disease the identification of NET with CEUS as a malignant lesion is more difficult. The sensitivity of CEUS in identifying malignancy based on the lack of portalvenous enhancement is higher for metastases of other origin.

Sonographic detection of perihepatic lymphadenopathy is an indicator for primary sclerosing cholangitis in patients with inflammatory bowel disease.

AIM: Primary sclerosing cholangitis (PSC) is a frequent complication in patients with inflammatory bowel disease (IBD). While hyperplasia of the perihepatic lymph nodes has been described in patients with PSC, its prevalence and cause in IBD patients remains obscure. In the present study we address the question of whether ultrasound (US) examination is useful to detect perihepatic lymphadenopathy and improve the diagnostic accuracy for PSC in patients with underlying IBD. METHODS: A total of 310 consecutive IBD patients were prospectively evaluated by US for enlarged perihepatic lymph nodes, as well as serologic testing for cholestasis-indicating enzymes. In patients with positive test results, viral or autoimmune liver disorders were excluded by serum testing. Next, the presence of PSC was confirmed/excluded by endoscopic retrograde cholangiography (ERC). RESULTS: Perihepatic lymphadenopathy was detected by US in 27 of 310 (9%) patients. In 9 (33%) of those, serologic testing identified an underlying autoimmune or viral hepatitis. In the remaining 18 patients, ERC confirmed PSC in 17 (94%) and excluded it in 1. Elevated cholestasis parameters were found in 43 of 310 (14%) patients and 5 (12%) of those were diagnosed with autoimmune or viral hepatitis. In the remaining 38 patients, ERC confirmed PSC in 15 (39%) and excluded it in 23 (61%). Therefore, when autoimmune or viral hepatitis was excluded, enlarged lymph nodes in US predicted PSC more accurately than conventional serum parameters alone (PPV 94 and 39%, respectively [ P<0.001]), and the sensitivity ratio increased by a factor of 1.13 in favor of the US examination. CONCLUSION: In patients with IBD, detection of enlarged perihepatic lymph nodes is a highly predictive indicator for the presence of PSC. Alternative causes of perihepatic lymphadenopathy have to be excluded.