H.-U. Kauczor

MR Angiography: clinical applications in thoracic surgery

MR angiography (MRA) is a promising completion of MR imaging in the preoperative assessment of pulmonary and mediastinal tumours. Scan acquisition was done by sequential FLASH 2D angiograms (TR = 30 ms, TE = 10 ms, FA = 30°), one section per breathhold, section thickness 5 mm with 1 mm overlap between sequential sections. An automated control procedure allowed individiual continuation of the examination. Postprocessing by a maximum-intensity-projection algorithm using angiograms of interest (AOI) resulted in 3D reconstructions illustrating vascular anatomy and avoiding superimposition. This technique was evaluated in a prospective study of 15 patients with malignant intrathoracic tumours. The results were validated by conventional angiographic procedures such as pulmonary angiography, digital subtraction angiography or cavography. Complementing spin-echo (SE) imaging, MRA provided diagnostic information about vessel displacement, stenosis and perfusion defects due to space-occupying lesions. Thus MRA was helpful in planning thoracic surgery.

Late bone marrow changes in Hodgkin's disease patients: a characterization with proton chemical shift imaging

Our aim was to measure, by quantitative chemical shift imaging (CSI), the late therapy-induced changes in bone marrow (BM) of Hodgkins disease (HD) patients. Fifteen HD patients treated with radiotherapy alone and radiochemotherapy (age at treatment between 11 and 50 years; post-treatment interval between 11 and 50 years; post-treatment interval between 15 and 127 months; applied dose 25.5 to 50 Gy), were studied with a 1.5 T MR imager. For the fat-water separation in-phase and opposed-phase (SE 1200/22) images were generated according to the Dixon method, with a modified post-processing. Long-term fatty replacement was seen in the irradiated BM only. The radiation fields were visualized as areas of high signal intensity in the T1-weighted images. There was a marked increase of the relative fat signal fraction in quantitative CSI without time, dose and age dependent recovery within the investigated ranges.Fatty replacement of the irradiated BM is a long-term effect in HD patients, probably induced by an obliteration of the microvasculature with consecutive fatty metaplasia.

An optimized examination protocol for contrast-enhanced cervical and mediastinal CT

We compared an optimized contrast-enhanced CT technique for the neck and upper mediastinum with a conventional technique and with nonenhanced images, using densitometric measurements. The optimized protocol included slice thickness, infusion rate, postural maneuvers, and manipulation of the gantry tilt. Densitometric evaluation showed significantly higher enhancement values in vessels and metastases with the optimized protocol than with conventional technique, without significant enhancement in muscle. Semiquantitative assessment demonstrated significantly better image quality with the optimized protocol. The optimized technique has been implemented into routine use.

Abstract 79: The relationship between abdominal fat distribution, vitamin D levels, and physical activity in colorectal cancer patients: A pilot study.

Abstract Introduction: Abdominal obesity, low physical activity and low levels of Vitamin D (Vit D) are associated with an increased risk for colorectal cancer (CRC). Physical inactivity contributes to obesity – an emerging global health burden. Individuals with the same body mass index (BMI) may vary in the distribution of subcutaneous and visceral abdominal fat. Subcutaneous and visceral fat differ in their metabolic functions. Moreover, Vit D is metabolized in adipose tissue; however, it is unclear if Vit D levels are influenced by the amount and the distribution of adipose tissue. Decreased levels of Vit D are found in obese subjects and a positive association between physical activity and Vit D levels is currently discussed. It is still unknown how this triangle relationship is displayed in CRC patients and how it might influence the course of disease. Thus, within this pilot study we explored the relationship between abdominal fat distribution, plasma levels of Vit D, and metabolic equivalent of task (MET) level as a marker for intensity and energy expenditure of physical activity in CRC patients. Methods: This pilot study was conducted on 194 CRC patients from the ColoCare Study, a cohort of newly-diagnosed stage I-IV CRC patients (age>18). Plasma 25(OH)VitD3 levels were measured by LC/MSD. BMI was calculated (kg/m2) and the absolute abdominal fat and the distribution of subcutaneous and visceral abdominal fat was assessed by abdominal computed tomography (CT) scans. The total (TFA), subcutaneous (SFA) and visceral fat area (VFA) is presented as an area (cm2) on level L3/L4. To assess physical activity we calculated the individual MET h/week from questionnaire data (based on the VITAL study questionnaire, FHCRC, Seattle). Spearman correlation analysis was used to assess the relationship between abdominal fat distribution, Vit D levels (adjusted for season), and METs. Moreover, subgroup analyses in male subjects were performed whereas sample size was too small for further subgrouping. Results: Study participants were on average 62 years old and diagnosed with either colon (44%), rectal (50%) or rectosigmoid (6%) primary cancer. Data were available on n=186 (BMI), n=118 (CT scans), n=133 (Vit D) and n=96 (MET) subjects based on sequential implementation of assessments. Only correlations with at least 40 individuals are reported. Our evaluation suggests a negative association between Vit D and VFA (r=-0.14, p=0.20). However, no association was found for BMI with Vit D and MET levels, respectively. MET levels were negatively correlated with VFA/SFA ratio (r=-0.22, p=0.13). In male patients MET levels were positively correlated with SFA (r=0.27, p=0.08) and negatively correlated with VFA/SFA ratio (r=-0.41, p<0.01). Conclusion: Our pilot data suggest that an increased portion of visceral but not subcutaneous fat may be linked to lower levels of Vit D. Furthermore, higher MET levels may be associated with a higher visceral/subcutaneous fat ratio and might influence Vit D levels by changes in abdominal fat distribution. Additional data collection is underway and will be presented. Citation Format: Jürgen Staffa, Johanna Welzel, Katharina Buck, Hanna Högenauer, Petra Schrotz-King, Nina Habermann, Dominique Scherer, Stephanie Tosic, Verena Widmer, Clare Abbenhardt, Gerd Würtele, Robert Owen, Michael Hoffmeister, Hermann Brenner, Jenny Chang-Claude, Hans-U. Kauczor, Cornelia M. Ulrich. The relationship between abdominal fat distribution, vitamin D levels, and physical activity in colorectal cancer patients: A pilot study. [abstract]. In: Proceedings of the AACR Special Conference on Post-GWAS Horizons in Molecular Epidemiology: Digging Deeper into the Environment; 2012 Nov 11-14; Hollywood, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(11 Suppl):Abstract nr 79.

Texture Analysis of B-Scan Images: Transferability between Different Ultrasound Scanners

Tissue characterization based on texture analysis of B-scan images provides objective parameters for the description of ultrasound images.

Magnetic Resonance Imaging and Magnetic Resonance Angiography in Treatment Planning and Response Monitoring of Single High-Dose Radiotherapy in Intracerebral Arteriovenous Malformations

Arteriovenous malformations (AVM) are regarded as congenital anomalies consisting of a racemose convolution of pathological vessels which predispose to intercerebral bleeding. The bleeding risk is about 4% per year, with a combined rate of major morbidity and mortality of 2.7% per year (Ondra et al. 1990). Cerebral AVM can be graded according to Spetzler et al. (1986). This system is based on the size of the AVM, localization of draining veins, and eloquence of adjacent brain tissue. It is derived from the potential postoperative complications, such as neurological deficits and mortality. AVMs of grade I or II are easily resectable, while those of grade IV or V are correlated with a high risk of major postoperative neurological deficits. This grading allows comparison with other therapeutic approaches: (a) embolization is very helpful preoperatively in preventing excessive bleeding but does not obliterate a large AVM alone (Fox et al. 1990); (b) stereotactic single high-dose radiotherapy, or “radiosurgery,” shows good results for complete occlusion of the AVM after a latency of approximately 2 years (Engenhart et al. 1989).