[Radiological diagnostic workup of liver tumors]. / Radiologische Diagnostik bei Lebertumoren.

The imaging of focal liver lesions is a common task in daily radiological routine. The objectives of diagnostic imaging are, in addition to lesion detection, the characterization of the lesion as well as the follow-up assessment after surgical or local treatment or under systemic therapy. This article presents the typical morphologies observed in computed tomography and magnetic resonance imaging of hepatocellular carcinomas and intrahepatic cholangiocarcinomas as the most important representatives of primary malignant liver tumors and juxtaposes them with benign primary liver lesions such as adenoma and focal nodular hyperplasia (FNH). In addition, relevant technical aspects of imaging are briefly summarized. Finally, the main and additional criteria of the Liver Imaging Reporting and Data System (LI-RADS®) classification, which are becoming increasingly established clinically for the evaluation of liver lesions in the cirrhotic liver, are presented.

Impact of CT parameters on the physical quantities related to image quality for two MDCT scanners using the ACR accreditation phantom: A phantom study.

INTRODUCTION: To evaluate the image quality provided by MDCT scanners using an ACR phantom an to find out the relationship between CT parameters and physical quantities related to image quality. METHODS: A GE Lightspeed VCT and a GE Lightspeed Pro 16 are used. The ACR phantom consists of four modules for evaluating physical parameters. The image quality parameters, such as CT number, linearity, CNR, image uniformity, SNR and at least spatial resolution using MTF, by different sets of image acquisition protocols (IAPs) are characterized. The influences of the IAPs on the physical quantities are also discussed. RESULTS: The CT numbers behaved linearly relative to material density for all tube voltages. The impact of the tube current on the CT numbers is neglectable. However, the variation of the tube current reflects in the CT number uncertainties. The CNR are altered by changing the IAPs. 50% MTF decreases from 6.2 to 3.6 lp/cm and from 6.5 to 3.7 lp/cm using Lung and Soft kernel for the Lightspeed VCT and Lightspeed Pro 16 scanner, respectively. CONCLUSION: The dependence of the image quality parameters on reconstruction kernels, tube peak voltages, tube currents and the slice thicknesses has been discussed. The tube peak voltage has the most influence on the CT numbers. The results indicate that the reconstruction kernel has the main impact on the spatial resolution. The spatial resolution dependence on the tube voltages, tube currents and slice thicknesses can be ignored.

Proof of principle for bevacizumab activity in desmoid-type fibromatosis.

BACKGROUND: Desmoid-type fibromatosis (DF) is a rare disease, which often occurs in young adults. Medical treatment is an important option in the treatment algorithm of DF. Different chemotherapeutic regimens showed clinical activity in DF, but overall treatment tolerability remains poor for this patient cohort. Novel approaches investigated tyrosine kinase inhibitors in DF, but tolerability remained an issue. CASE PRESENTATION: We treated a patient with progressive DF after failure of chemotherapy for 1 year with singe agent bevacizumab. He achieved a symptomatic and radiologic response while attainning excellent tolerability. CONCLUSIONS: This is the first report on single agent bevacizumab in DF, which showed both, good tolerability and efficacy in our patient, thereby warranting future trials in DF.

C-arm CT--an adjunct to DSA for endoleak classification in patients with endovascular repair of abdominal aortic aneurysms.

PURPOSE: To assess the benefit of C-arm CT for classification and procedural guidance during interventional therapy of endoleaks (EL) after endovascular repair (EVAR) of abdominal aortic aneurysms (AAA). MATERIALS AND METHODS: 12 patients with EL diagnosed with CT but undetermined EL classification (ELC) underwent DSA and transarterial contrast-enhanced C-arm CT. ELC (based on DSA, C-arm CT and CT) assessed during the angiographic procedure served as the standard of reference (SOR). Subsequently, ELC was assessed by a blinded second reader based on DSA or C-arm CT and compared to the SOR. In the case of an interventional procedure (n = 6), the added value of C-arm CT for procedure guidance was assessed retrospectively (1: essential, 2: helpful, 3: additional information without impact, 4: no additional information). RESULTS: The blinded reader classified 9/12 EL using DSA alone and 11/12 EL using C-arm CT alone. In one patient, the temporal resolution provided by DSA was essential to establish the diagnosis. In 6 patients, a type 2 EL without need for therapy was diagnosed. The remaining 6 patients showed EL that were treated immediately (type 1 EL, n = 4: 3 stent graft extensions and one angioplasty; type 2 EL, n = 1: translumbar embolization; type 3 EL, n = 1: sealing of a fabric tear). The information provided by C-arm CT was assessed to be essential in three patients and helpful in two. CONCLUSION: C-arm CT is an ideal adjunct to DSA. In our pilot study, it helped to localize and classify endoleaks more reliably than DSA alone.

[Effects of MRI-assayed microvascular permeability on the accumulation of vinorelbine in xenograft tumors]. / Einfluss der mittels MRT bestimmten mikrovaskulären Permeabilität auf die Akkumulation von Vinorelbine in experimentellen Xenograft-Tumoren.

PURPOSE: To determine the effects of MRI-assayed vascular leakiness on the delivery of macromolecular therapeutics to tumors. MATERIALS AND METHODS: MDA-MB 435 tumors, subcutaneously implanted into nude rats were treated with a single dose of bevacizumab at levels of 0.1 mg (n = 5) or 1.0 mg (n = 10) or received saline (control animals, n = 8). After 24 hours, albumin-(Gd-DTPA) (30)-enhanced MRI was performed. Just prior to MRI, the cytotoxic drug vinorelbine was administered intravenously. Upon completion of the MR experiment, tumor vinorelbine concentrations were quantified by high performance liquid chromatography (HPLC). Vascular leakiness (K (PS)) was calculated based on the MRI data using a pharmacokinetic model. RESULTS: K (PS) was calculated as 3.70 +/- 1.12 (control tumors), 1.95 +/- 0.70 (0.1 mg group) and 0.75 +/- 0.46 microl min (-1)cm (-3) (1.0 mg group). K (PS) was significantly higher in the control group compared to the 1.0 mg bevacizumab group. Vinorelbine concentrations were measured as 409.4 +/- 109.7 (control tumors), 387.5 +/- 47.5 (0.1 mg group) and 250.7 +/- 71.9 (1.0 mg group). These differences were not significant. A moderate and significant correlation was found between K (PS) and Vinorelbine concentrations in tumors (r = 0.49, p < 0.05). CONCLUSION: MRI-assayed K (PS) based on dynamic MRI enhanced by albumin-(Gd-DTPA) (30) correlated significantly with vinorelbine accumulation in experimental xenograft tumors under angiogenesis inhibition. Thus, the MRI technique applied in our study could potentially help to predict accumulation of macromolecular cytotoxic drugs and to optimize individual therapeutic regimes in tumors.

Dual energy CT of peripheral arteries: effect of automatic bone and plaque removal on image quality and grading of stenoses.

PURPOSE: To evaluate the effect of automatic bone and plaque removal on image quality and grading of steno-occlusive lesions in patients undergoing dual energy CT angiography (CTA) of lower extremity. MATERIALS AND METHODS: Dual energy (DE) runoff CTA was performed in 50 patients using the following parameters: collimation 2 x 32 x 0.6; tube potentials, 80 kV and 140 kV; reconstructed slice thickness 1mm. 100 mL iomeprol 400 and 50 mL saline were injected at 4 mL/s. Separate datasets were calculated for each of the two tubes and used to generate automatically bone-subtracted images (ABS) as well as bone and plaque subtracted images (ABPS). Residual bone in the ABS dataset was removed manually (=ABS-B dataset). In addition, a weighted average dataset from both dual energy acquisitions resembling a routine 120 kV CT acquisition was used for standard manual bone subtraction (MBS). Operator time for bone removal was measured. Effectiveness of bone subtraction and presence of vessel erosions was assessed by two readers in consensus. Stenosis grading in plaque subtracted and unsubtracted images was assessed and correlated. RESULTS: Residual bone fragments (ribs: 46%, patella: 25%, spine: 4%, pelvis: 2%, tibia 2% of patients) were only observed with ABS. The time needed to manually remove these residual bones was 2.1+/-1.1 min and was significantly lower than the duration of manual bone removal (6.8+/-2.0 min, p<0.0001, paired t-test). A total of 1159 arteries were analyzed. Compromising vessel erosions were observed less frequently in the ABS-B dataset (10.6%) than in the MBS dataset (15.2%, p<0.001, wilcoxon's signed rank test). A total of 817 steno-occlusive lesions were assessed. While the agreement of grading of steno-occlusive lesions was good at the levels of the aorta and the pelvic arteries (kappa=0.70 in both, Cohen's kappa statistics), it was moderate at the level of the thigh arteries (kappa=0.57) and poor at the level of the calf (kappa=0.16). CONCLUSION: DE CTA has substantial advantages over conventional CTA. Automatic bone subtraction is more time efficient and reliable. Automatic plaque subtraction for the first time provides a true CTA-luminogram which is easy to interpret and reduces the need for further post-processing. DE CTA provides best results in arteries of the thigh; below the knee, plaque subtraction is less accurate.

[Feasibility and optimization of the combined injection of contrast medium and normal saline with a single-syringe CT injection system]. / Durchführbarkeit und Optimierung einer kombinierten Kontrastmittel- und Kochsalzinjektion mit einem CT-Einzelinjektorsystem.

PURPOSE: To optimize the technique of injecting contrast medium followed by saline flush with a single-syringe CT injection system. MATERIALS AND METHODS: A CT injection system with a single syringe was filled with 100 ml of contrast medium (Iopromide 300 or Iomeprol 400) and 50 ml of normal saline solution. The following variables were evaluated: filling sequence, filling rate, syringe position during filling, ejection rate and delay before ejection. In consecutive portions of 10 ml, the whole volume was continuously ejected into test tubes that were subjected to CT densitometry on these test tubes. Each experiment was performed three times. RESULTS: Filling the syringe first with saline solution and subsequently with contrast medium resulted in no substantial mixing, whereas filling in the reverse order caused noticeable mixing of both solutions. Manual filling at a rate < or = 1 ml/s gave the best results. At faster filling rates (4 ml/s, 10 ml/s), substantial mixing of contrast agent and saline solution was observed. The separation of the two liquids was optimal when the syringe nozzle was pointed downward. Ejection rate (3 ml/s, 4 ml/s) and time delay between filling and ejection (0 min, 10 min) did not influence the distribution of density. The maximum iodine concentration using this approach was 235 mg/ml for Iopromide 300 and 327 mg/ml for Iomeprol 400. This indicates a reduction of the maximum iodine concentration of up to 28 % even when using the optimal technique for controlling mixing of both liquids. CONCLUSION: Manual filling of the CT injection syringe with saline solution followed by contrast media with the syringe nozzle pointed downward provides the best separation between contrast medium and normal saline solution but reduces the maximum iodine concentration by up to 28 %. For examinations requiring a high iodine concentration, such as CT-angiography, an iodine concentration of 400 mg/ml should be selected for the combined injection of contrast medium and normal saline solution with a single-syringe CT injection system.

Suicide by self-immolation in Berlin from 1990 to 2000.

We investigated retrospectively the forensic autopsy cases of suicide by self-immolation in Berlin from 1990 to 2000. There were 46 cases (35 men and 11 women), corresponding to 0.76% of all known suicides committed in Berlin during this period. The most common reasons for self-immolation were separation from a partner or financial problems. Two individuals had political reasons. There was a history of mental disturbances in 65% of these suicide cases. The location of the self-immolation was outdoors in 65%, the rest were indoors, except for three victims, who committed suicide in their cars. In nearly all cases, the individuals had doused themselves with an inflammable fluid, usually petrol. One-third of the victims died from burn shock, about 20% from a combination of severe burns and inhalation trauma. The median body surface area burnt was 78% for all cases. The blood had a mean 21% carboxyhemoglobin concentration and 0.07 microg/ml of cyanide. Suicide by self-immolation was committed under the influence of drugs in nine cases and of alcohol in 11 cases.