41 research outputs found
The EarthCARE satellite: the next step forward in global measurements of clouds, aerosols, precipitation, and radiation
The collective representation within global models of aerosol, cloud, precipitation, and their radiative properties remains unsatisfactory. They constitute the largest source of uncertainty in predictions of climatic change and hamper the ability of numerical weather prediction models to forecast high-impact weather events. The joint European Space Agency (ESA)–Japan Aerospace Exploration Agency (JAXA) Earth Clouds, Aerosol and Radiation Explorer (EarthCARE) satellite mission, scheduled for launch in 2018, will help to resolve these weaknesses by providing global profiles of cloud, aerosol, precipitation, and associated radiative properties inferred from a combination of measurements made by its collocated active and passive sensors. EarthCARE will improve our understanding of cloud and aerosol processes by extending the invaluable dataset acquired by the A-Train satellites CloudSat, Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and Aqua. Specifically, EarthCARE’s cloud profiling radar, with 7 dB more sensitivity than CloudSat, will detect more thin clouds and its Doppler capability will provide novel information on convection, precipitating ice particle, and raindrop fall speeds. EarthCARE’s 355-nm high-spectral-resolution lidar will measure directly and accurately cloud and aerosol extinction and optical depth. Combining this with backscatter and polarization information should lead to an unprecedented ability to identify aerosol type. The multispectral imager will provide a context for, and the ability to construct, the cloud and aerosol distribution in 3D domains around the narrow 2D retrieved cross section. The consistency of the retrievals will be assessed to within a target of ±10 W m–2 on the (10 km)2 scale by comparing the multiview broadband radiometer observations to the top-of-atmosphere fluxes estimated by 3D radiative transfer models acting on retrieved 3D domains
Bildgebende Diagnostik des Rektumkarzinoms : Moderne Verfahren und zukuenftige Entwicklung
Die Individualisierung bzw. Stadienadaptation der Therapiekonzepte beim Rektumkarzinom hat zur Erweiterung der Anforderung an die bildgebende Diagnostik gefuehrt. Der gezielte Einsatz neoadjuvanter Behandlungskonzepte und die v. a. hinsichtlich der Kontinenzerhaltung optimierten Operationstechniken erfordern eine praezise praeoperative Diagnostik hinsichtlich der Tumorausdehnung, des Lymphknotenstatus sowie der Beurteilung von Organen mit haeufigem Befall durch eine Fernmetastasierung. Fuer die Diagnostik des Rektumkarzinoms stehen eine Reihe bildgebender Methoden zur Verfuegung: Etablierte Verfahren stellen der kolorektale Kontrasteinlauf, die endoluminale Sonographie und die Schnittbildverfahren Computertomographie und Magnetresonanztomographie dar. Parallel hierzu werden die Immunszintigraphie und die Positronenemissionstomographie auf ihren komplementären oder additiven Stellenwert geprueft. Technische Weiterentwicklungen wie die 3D-Sonographie, die endoluminale MRT und die Multislice-CT erfordern eine neue Bewertung dieser Methoden
Vergleich von endorektaler MRT (EMRT) und endorektaler Sonographie (ES) nach operativer Therapie von Rektumkarzinomen zum Ausschluss von Rezidiven oder Residualtumoren [Comparison between endorectal MRI (EMRTI) and endorectal sonography (ES) after surgery or therapy for rectal tumors to exclude recurrent or residual tumor]
PURPOSE: This study was designed to evaluate the accuracy and limitations for staging of contrast-enhanced endorectal MR imaging comparing with transrectal US for restaging of rectal lesions after surgery or after therapeutic radiation. Both methods were correlated with histologic findings. METHOD/MATERIALS: The efficacy of these both methods was evaluated in 30 patients with supposed residual or recurrent rectal neoplasms. Contrast enhanced (bolus injection of 0.1 mmol/kg b.w. Gd-DTPA) endorectal MR imaging was performed using a 1.5 Tesla Magnetom. In addition endosonography (7.5 x or 10-MHz transducer) was used. RESULTS: In 8 patients with rectal adenoma after electro-laser resection, 8 patients with rectal carcinoma stage pT1 after transanal resection, 8 patients with rectal carcinoma stage pT2 and 6 patients with rectal carcinoma stage pT3 after regional hyperthermia with radiochemo-therapy, the following results were obtained during the postsurgical or posttherapeutical follow-up with respect to histopathological evaluation: exact staging in 86.6 % with EMRI and 63.3 % in ES, overstaging in 8 % (EMRI) and 23 % (ES), understaging in 0 % (EMRI) and 7 % (ES). The highest diagnostic accuracy was shown in EMRT in patients with rectal adenoma and rectal carcinoma (pT1) and after electro-laser resection or transanal resection during follow-up. CONCLUSIONS: Contrast enhanced endorectal MR imaging appears to be very promising for accurate posttherapeutical staging of rectal cancer and helpful in the diagnosis of recurrence or the differentiation between scar tissue and residual rectal tumor
Prospective comparison of transcutaneous 3-dimensional US cholangiography, magnetic resonance cholangiography, and direct cholangiography in the evaluation of malignant biliary obstruction
Background: The purpose of this study was to investigate the ability of transcutaneous three-dimensional US cholangiography to depict the biliary tree in malignant obstruction, compared with that of MRCP and direct cholangiography. Methods: Three-dimensional US and MRCP and direct cholangiography were performed in 40 patients with suspected malignant biliary obstruction. Diagnostic quality of the images, presence, level, and cause of ductal obstruction were assessed in a prospective, blinded fashion. The results were correlated with consensus interpretation (3 investigators), intra-operative findings, and histopathology or clinical follow-up. Results: Three-dimensional US produced cholangiographic images of diagnostic quality. The appearance of these images was similar to that of MRCP or ERCP/percutaneous transhepatic cholangiography images. All modalities were highly sensitive in the detection of biliary dilatation. The accuracy of 3-dimensional US, MRCP, and ERCP/percutaneous transhepatic cholangiography in determining the level of obstruction was, respectively, 92%, 95%, and 98%. Transcutaneous 3-dimensional US and MRCP accurately identified the cause of obstruction in, respectively, 90% and 95% of cases. Direct cholangiography revealed the correct diagnosis in 95% of the patients. Conclusions: Three-dimensional US cholangiography is a new, noninvasive method with the capability to produce diagnostic cholangiograms. Three-dimensional US cholangiography may be used increasingly as an initial test to select patients who require further diagnostic evaluation by MRCP or therapeutic ERCP
Surgical strategies for gastric cancer with synchronous peritoneal carcinomatosis
BACKGROUND: Gastric cancer frequently spreads to the peritoneal cavity. Whether laparoscopy is useful in planning therapy remains controversial. The aim of this study was to investigate the value of laparoscopy and to develop a therapeutic algorithm. METHODS: Six hundred and sixty consecutive patients with gastric cancer were included in this prospective observational study. The sensitivity of abdominal ultrasonography, computed tomography (CT) and laparoscopy for detecting peritoneal carcinomatosis was compared. The lesions were biopsied and classified as P1, P2 or P3 according to the recommendations of the Japanese Research Society for Gastric Cancer. Prognosis was determined according to the stage of peritoneal carcinomatosis and therapeutic procedure adopted. RESULTS: One hundred and ten (16.7 per cent) of 660 patients presented with synchronous peritoneal carcinomatosis. The sensitivity for detecting peritoneal carcinomatosis was 85 per cent for laparoscopy compared with 19 per cent for ultrasonography and 28 per cent for CT. Patients with P3 disease did not benefit from additional surgery compared with chemotherapy alone. Those with P1 carcinomatosis had improved survival rates after complete resection followed by chemotherapy. CONCLUSION: Laparoscopy improves the detection and classification of peritoneal carcinomatosis, and offers patients with gastric cancer a more individualized and effective therapy
Prospective comparison of endorectal ultrasound, three-dimensional endorectal ultrasound, and endorectal MRI in the preoperative evaluation of rectal tumors. Preliminary results
Background: The aim of this study was to compare the value of endorectal ultrasound (EUS), three-dimensional (3D) EUS, and endorectal MRI in the preoperative staging of rectal neoplasms. Methods: Thirty consecutive patients with rectal tumors were assessed by EUS and endorectal MRI. Additionally, three-dimensional ultrasound was performed in a subgroup of 25 patients. EUS data were obtained with a bifocal multiplane transducer (10 MHz) and processed on a 3D ultrasound workstation. MR imaging was carried out with a 1.5 T superconducting unit using an endorectal surface coil. Results: EUS was carried out successfully in all 30 patients, whereas endorectal MRI was not feasible in two patients. Compared with the histopathological classification, EUS and endorectal MRI correctly determined the tumor infiltration depth in 25 of 30 and 28 patients, respectively. The comparative accuracy of EUS, 3D EUS, and endorectal MRI in predicting tumor invasion was 84%, 88%, and 91%, respectively. EUS, three-dimensional EUS, and endorectal MRI enabled us to assess the lymph node status correctly in 25, 25, and 24 patients, respectively. Both three-dimensional EUS and endorectal MRI combined high-resolution imaging and multiplanar display options. Assessment of additional scan planes facilitated the interpretation of the findings and improved the understanding of the three-dimensional anatomy. Conclusion: The accuracy of three-dimensional EUS and endorectal MRI in the assessment of the infiltration depth of rectal cancer is comparable to conventional EUS. One advantage of both methods is the ability to obtain multiplanar images, which may be helpful for the planning of surgery in the future
Response to Preoperative short-course radiotherapy in locally advanced rectal cancer: Value of F-fluorodeoxyglucose positron emission tomography
Background:(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) is increasingly used to monitor response to multimodality cancer treatment. Preoperative short-course radiotherapy (SCRT) has been shown to improve outcome in locally advanced rectal cancer (LARC). We evaluated the value of FDGPET in monitoring response to SCRT. Patients and Methods: 32 patients with LARC scheduled for SCRT underwent FDG-PET, magnetic resonance imaging and endorectal ultrasound both before and after SCRT. A comparison group of 16 patients, undergoing preoperative radiochemotherapy (RCT), received an extra FDG-PET 17 days after starting RCT (effective dose of 30.6 Gy). For response assessment, FDG uptake (maximum standardized uptake value, SUVmax), percent SUVmax difference, tumor regression grade (TRG), and UICC downstaging and downsizing were considered. Results: SCRT resulted in a significant median SUVmax reduction of 39.3%. Median SUVmax reduction did differ between SCRT and the early scans after 17 days of RCT (39.3 vs. 50.8%). Downstaging after SCRT was observed in 16/32, downsizing in 7/32 patients. There was no correlation between SUVmax reduction and downstaging/ downsizing or TRG. Conclusion: For the first time, we were able to demonstrate functional response after SCRT. In contrast to morphological imaging and histopathology, our results indicate that FDG-PET can monitor early effects of SCRT. Further followup is warranted to establish SUVmax reduction as a surrogate marker for the response of SCRT