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Biomedical subjects

H Kühl

Publications and source records attributed to H Kühl.

At least 19 recordsLinked to original sources
PubMed2007

[Liver biopsy under guidance of multislice computed tomography: comparison of 16G and 18G biopsy needles].

BACKGROUND: Percutaneous cutting needle biopsy of focal liver lesions under CT guidance has established itself as a standard method. The purpose of this study was to evaluate which diagnostic quality can be achieved under guidance of multislice CT (MSCT) and with the use of different needle sizes. METHODS: The data of 163 MSCT-guided core biopsies of focal liver lesions were evaluated. A 16G biopsy needle was used in 121 cases and an 18G needle in 42 cases. RESULTS: The sensitivity, specificity, and accuracy for all biopsies were 93.3, 100.0, and 94.5%. The corresponding values were 97.2, 100.0, and 97.5% for the 16G needle and 78.6, 100.0, and 85.7% for the 18G needle, respectively. A definite histological diagnosis could be obtained in 90.0% of the cases (16G 94.0%, 18G 75.8%). These differences were statistically highly significant. Bleeding complications were recognized in seven biopsies (4.3%). In one patient a fatal bleeding occurred after the biopsy. Median biopsy duration was 27 min. CONCLUSIONS: Core biopsy under MSCT guidance is a fast and very accurate method to obtain a histological diagnosis in focal liver lesions. The usage of a 16G needle in comparison to an 18G needle yielded a significantly higher rate of correct results with regard to differentiation between benign and malignant disease as well as establishing a definite histological diagnosis. For an accurate diagnosis of liver lesions a 16G needle is recommended. After biopsy, the patients have to be closely monitored.

Aged↗
PubMed2006

[Radiofrequency ablation of malignant liver tumors: use of a volumetric necrosis-tumor ratio for local control].

PURPOSE: Sufficient safety margins are essential for preventing local tumor recurrence after radiofrequency ablation RFA of malignant liver tumors. The aim was to determine the initial tumor volume, ablation necrosis volume, and the necrosis-tumor quotient in order to compare these parameters with the rate of local control during follow-up. MATERIALS AND METHODS: 35 patients with 53 tumor nodules (29 colorectal metastases and 24 HCC nodules) were enrolled. RFA procedures were performed under CT guidance with intravenous conscious sedation. Tumor volumes were measured based on CT data sets and the necrosis volume was assessed using the sum-of-area method. A volumetric necrosis/tumor quotient (NTQ) was calculated for all lesions. Follow-up examinations were performed after 3, 6, and 12 months and then on a yearly basis to identify local recurrent tumors. RESULTS: The CRC metastases and HCC nodules had a median tumor volume of 8.3 ml and 7.4 ml, respectively. The mean ablation volumes were 37.6 ml and 29.5 ml, respectively. This resulted in a median NTQ of 3.9 for metastases and 3.4 for HCC. The follow-up (mean time 18 months) revealed local tumor recurrence in 16 of 29 (55 %) metastases and 10 of 24 (42 %) HCC nodules. In lesions with local recurrence, the initial tumor volume was significantly greater and the NTQ was significantly smaller. A threshold value of 3.4 for NTQ has the highest predictive value for local tumor recurrence. CONCLUSION: The volumetric necrosis/tumor quotient NTQ makes it possible to predict the local outcome and can be used for the planning of additional therapy.

Aged↗
PubMed2005

Analysis of myocardial deformation based on pixel tracking in two dimensional echocardiographic images enables quantitative assessment of regional left ventricular function.

OBJECTIVE: To evaluate whether myocardial strain and strain rate calculated from two dimensional echocardiography by automatic frame-by-frame tracking of natural acoustic markers enables objective description of regional left ventricular (LV) function. METHODS: In 64 patients parasternal two dimensional echocardiographic views at the apical, mid-ventricular and basal levels were obtained. An automatic frame-by-frame tracking system of natural acoustic echocardiographic markers was used to calculate radial strain, circumferential strain, radial strain rate and circumferential strain rate for each LV segment in a 16 segment model. Cardiac magnetic resonance imaging (cMRI) was performed to define segmental LV function as normokinetic, hypokinetic or akinetic. RESULTS: Image quality was sufficient for adequate strain and strain-rate analysis from two dimensional echocardiographic images obtained from parasternal views in 88% of segments. Obtained radial strain data were highly reproducible and analysis was affected by only small intraobserver (mean 4.4 (SD 1.6)%) and interobserver variabilities (7.3 (2.5)%). Each of the analysed strain and strain-rate parameters was significantly different between segments defined as normokinetic, hypokinetic or akinetic by cMRI (radial strain 36.8 (10.5)%, 24.1 (7.5)% and 13.4 (4.8)%, respectively, p < 0.001). Peak systolic radial strain enabled detection of hypokinesis or akinesis with a sensitivity of 83.5% and a specificity of 83.5% (cut off value 29.1%, receiver operating characteristic (ROC) curve area 0.905, 95% CI 0.883 to 0.923). Peak systolic radial strain analysis also enabled detection of akinesis versus hypokinesis with a sensitivity of 82.7% and a specificity of 94.5% (cut off value 21.0%, ROC curve area 0.946). Peak systolic radial strain-rate analysis was less accurate than peak systolic radial strain analysis to detect cMRI-defined segmental function abnormalities. The accuracy of peak systolic circumferential strain and strain rate was similar to that of corresponding radial parameters. CONCLUSIONS: Frame-by-frame tracking of acoustic markers in two dimensional echocardiographic images enables accurate analysis of regional systolic LV function.

Adult↗
PubMed2005

Disease course after liver transplantation for hepatocellular carcinoma in patients with complete tumor necrosis in liver explants after performance of bridging treatments.

AIM: To study the disease course of patients with hepatocellular carcinoma (HCC) showing complete tumor necrosis in their liver explants after undergoing bridging treatments followed by liver transplantation (LTx). PATIENTS AND METHODS: We evaluated data corresponding to 10 patients with liver cirrhosis undergoing bridging treatments for HCC prior to LTx. In all cases there was complete tumor necrosis in the explanted livers. RESULTS: There were 8 men and 2 women. Percutaneous radiofrequency ablation (RFA) was performed under computed tomographic guidance in 4 patients. The remaining 6 patients underwent transarterial chemoembolization (TACE). Five of them received one session of TACE, while the remaining one received a series of 4 sessions prior to LTx. Six patients had solitary nodules with a median diameter of 3.5 cm (range 2.5-4.2 cm). Four of them underwent RFA. Segmental tumor chemoembolization was performed in 2 patients. The remaining 4 patients had 2 tumors each with a median total diameter of 4.4cm (range 4.2-6.0 cm) prior to TACE. They underwent bilobar hepatic chemoembolization, which under staged the tumors prior to live donor liver transplantation (LDLTx). Six patients underwent deceased donor orthotopic liver transplantation. LDLTx was performed in 4 patients. Median waiting time to LTx was 53 days. All patients are alive without recurrence after a median follow-up of 19 months. CONCLUSION: Achievement of 100% tumor necrosis by means of bridging treatments followed by LTx for HCC is characterized by a very low recurrence rate and should receive further consideration and study.

Adult↗
PubMed2005

[Two cystic retroperitoneal lesions mimicking adrenal cysts].

Adrenal cysts are uncommon lesions and most of them are found incidentally during abdominal imaging. We report on two benign extraadrenal lesions mimicking adrenal tumors in abdominal imaging. The histopathological investigation of the lesions revealed a foregut duplication cyst of the lesser gastric curvature and an epithelial inclusion cyst (epidermoid cyst) in an intrapancreatic accessory spleen respectively.

Adrenal Gland Diseases↗
PubMed2005

Comparison of measured and calculated dose rates for the Castor HAW 20/28 CG.

In January 2003 neutron and gamma dose rate measurements at a CASTOR HAW 20/28 CG were performed by the Bundesamt für Strahlenschutz at Gorleben. First, commercial dose rate measurement devices were used, then spectral measurements with a Bonner sphere system were made to verify the results. Axial and circumferential dose rate profiles were measured near the cask surface and spectral measurements were performed for some locations. A shielding analysis of the cask was performed with the MCNP Monte Carlo Code with ENDF/B-VI cross section libraries. The cask was modelled 'as built', i.e. with its real inventory, dimensions and material densities and with the same configuration and position as in the storage facility. The average C/E-ratios are 1.3 for neutron dose rates and 1.4 for gamma dose rates. Both the measured and calculated dose rates show the same qualitative trends in the axial and circumferential direction. The spectral measurements show a variation in the spectra across the cask surface. This correlates with the variation found in the C/E-ratios. At cask midheight good agreement between the Bonner sphere system and the commercial device (LB 6411) is found with a 7% lower derived H*(10) dose rate from the Bonner sphere system.

Computer-Aided Design↗
PubMed2004

[Principles of PET/CT and clinical application].

Medicine today imposes high demands on diagnosing disease. Techniques should be preferably noninvasive, identify the disease at an early stage, and be quick and accurate. Frequently, these demands can only be met by employing various diagnostic modalities. Consequently, the integration of two imaging modalities, such as the combination of PET and CT, increases the quality of coregistration and facilitates a timely diagnosis. However, complex imaging procedures require a judicious choice of the areas of application. If, for example, both PET and CT are indicated then a combined PET/CT exam results in improved diagnosis, whereby the actual benefit will depend upon the clinical problem. Typically we expect an advantage of 10% with PET/CT compared to separate examinations with CT and PET. In addition, PET/CT allows for new indications and applications, which cannot be performed satisfactorily with independent examinations and retrospective image alignment. One example is the application of PET/CT in radiation therapy planning.

Artifacts↗
PubMed2003

[Tracheal rupture from blunt chest injury in a child].

Tracheobronchial lesions after blunt chest injury are rare. Diagnosis and therapy can prove to be challenging for the attending physician. Nonrecognition of this injury may entail severe complications. Herein we report the case of a 9-year-old girl with rupture of the trachea due to a fall against the handlebar of her kickboard. The clinical, radiological, and features of the therapy performed are discussed.

Athletic Injuries↗
PubMed2003

[Living organ donor transplantation--the German experience in comparison to others].

Living liver donation is a prominent and innovative method in the therapy of terminal liver disease in children and adults. Live donation of livers was first used in 1989 for children. After only 10 years, the concept was also established for application in adults. Due to the imminent lack of donor organs and the constantly increasing need of liver transplantation, this method will continue to grow in importance.

Adult↗
PubMed2002

[The value of computed tomography in the early treatment of seriously injured patients].

BACKGROUND: The availability of newer, faster computed tomography (CT) technology has engendered discussion about whole-body CT-scanning for primary radiological diagnostics of seriously injured patients. METHOD: Within a quality management system, the scaled, priority-oriented scheme of conventional radiological and CT-diagnostics used in each institution was analysed and compared with the possible benefit of whole-body CT-scanning. Every patient with severe trauma admitted directly from the scene of an accident, underwent basic radiological and sonographic diagnostics in the emergency room (ER). According to the findings, patients in a stable vital condition had CT-scans when indicated by the guidelines of the particular institution. RESULTS: From 5/1998 until 12/2000, a total of 832 patients were treated in the ER. Of those, 480 patients (average ISS 20) were admitted directly from the scene of the accident. Basic radiological - sonographic diagnostics (radiographs of cervical spine, chest, and abdomen, as well as abdominal sonography) took 15+/-8 min. Twenty-two (5%) of the patients in hemorrhagic shock needed emergency operations after 57+/-43 min. The remaining patients underwent further radiological diagnostics (spine, extremities etc.) after 44+/-27 min. In 79% (379) of patients, CT was indicated. Cranial CT for traumatic brain injury prevailed clearly with 74% of cases. Spine (24%), chest (18%), abdomen (5%) and pelvis (5%) were indicated comparatively less frequently. The incidence of delayed diagnoses (after ICU-admission) was 4% (22). In 2% (nine) of patients the lesions possibly could have been detected by a primary CT-scan. In the three cases with thoracic lesions, there was a deviation from the indication guidelines for thoracic CT as normally used in the institution. There were three cases of delayed diagnoses in both the cerebral (small contusion haematomas) region and the abdominal region. The abdominal lesions were detected by sonographic control examinations. No patient died because of a delayed diagnosis. The average X-ray dose was five times lower with the scaled diagnostic management comprising indicated CT when compared to the doses calculated for routine whole-body CT. CONCLUSION: While 74% of patients had cranial CT, only 25% needed CT for the trunk regions. Delayed diagnoses were rare and without severe consequences for the patient. Considering the five times higher X-ray doses combined with the possible time loss in patients with unstable conditions, primary whole-body CT-scanning should not be performed routinely when serious injury is suspected.

Adult↗
PubMed2002

Assessment of transcriptional gene activity in situ by application of HOPE-fixed, paraffin-embedded tissues.

We report the use of HOPE-fixation (HOPE = Hepes-Glutamic acid buffer mediated Organic solvent Protection Effect) for specimens utilized for in situ hybridization targeting mRNA. For this purpose, an optimized protocol was developed and repeatedly tested on HOPE-fixed lung specimens. We observed that neither pretreatment, permeabilizing the cells, nor prehybridization is necessary to generate signals. After deparaffinizing, the random primed digoxigenin-labeled probes are directly hybridized together with yeast tRNA for blocking unspecific signals. Detection was performed using anti digoxigenin antibodies conjugated with alkaline phosphatase and new-fuchsine or NBT/BCIP as substrates. The results were verified by RT-PCR and adequate negative controls. Signals for human surfactant protein-A and interferon-gamma-inducible protein-10 developed rapidly within 10 min, accompanied by high signal intensities comparable to those observed in immunohistochemistry. Signal enhancement by biotinyl-tyramide, although giving suitable results as well, did not lead to higher signal intensities, and thus was not necessary in conjunction with the probes tested so far. These experiments were performed with material stored under appropriate conditions (at +4 degrees C) up to five years. To sum up, these initial results, obtained with the novel HOPE-fixative, are promising as regards the enhancement of the capabilities of in situ hybridization in the future.

Cells, Cultured↗
PubMed2002

Comparative mapping of CDY and DAZ in higher primates.

The human male specific expressed gene families CDY and DAZ are known to be repetitively clustered in the Y-specific region of the human Y chromosome. Comparative FISH-mapping of DNA clones specific for CDY and DAZ resulted in a Y-specific but diverse signal pattern within the non-recombining region of the Y-chromosomes of human and great apes. It can be concluded that the non-recombining part of the Y-chromosomes including CDY and DAZ, was exposed to species-specific amplifications, diversifications and rearrangements. Evolutionary fast fixation of any of these variations was possible as long as they did not interfere with male fertility.

Animals↗
PubMed2001

Loss of the Y chromosomal PAR2-region in four familial cases of satellited Y chromosomes (Yqs).

Applying fluorescence in-situ hybridization (FISH) of various Y chromosomal DNA probes to four familial cases of human Yqs, it was possible to demonstrate that the formation of Yqs must have arisen from a reciprocal translocation involving the short arm of an acrocentric autosome and the heterochromatin of the long arm of the Y chromosome (Yqh). Breakpoints map within Yqh and the proximal short arm of an acrocentric autosome resulting in the gain of a nucleolus organizer region (NOR) including the telomere repeat (TTAGGG)n combined with the loss of the pseudoautosomal region 2 (PAR2) at the long arm of the recipient Y chromosome. In no case could the reciprocal product of an acrocentric autosome with loss of the NOR and gain of PAR2 be detected. Using the 15p-specific classical satellite-III probe D15Z1 in two of the four Yqs probands presented here, it could be shown that the satellited material originated from the short arm of chromosome 15. In contrast to the loss of PAR2 in Yqs chromosomes, another Y chromosomal variant (Yqh-) showing deletion of long-arm heterochromatin in Yq12 has retained PAR2 referring to an interstitial deletion of Yq heterochromatin in such deleted Y chromosomes.

Child, Preschool↗
PubMed2001

Pulsed tissue Doppler imaging to assess myocardial viability by quantification of regional myocardial functional reserve.

Dobutamine stress echocardiography (DSE) is used widely to evaluate myocardial viability, but is limited by the subjective nature of test interpretation. Assessment of systolic function by pulsed tissue Doppler imaging (TDI) during dobutamine stimulation may allow a more objective evaluation of myocardial functional reserve and, thus, myocardial viability. In 30 patients (58 +/- 9 years) with prior myocardial infarction, pulsed TDI with low dose dobutamine stress (10 microg/kg/min) was performed to assess myocardial viability. Qualitative assessment of two-dimensional (2-D) DSE and positron emission tomography (PET) were used for comparison. Peak systolic myocardial velocity was measured for each left ventricular segment (16 segments) at baseline and low dose dobutamine stress using pulsed TDI. The absolute and relative increases of peak systolic velocity from rest to low dose dobutamine stress were calculated. Three hundred sixty-four segments with adequate pulsed TDI tracing were divided according to either 2-D DSE or PET findings into normal, viable (mismatch), and nonviable (match) segments. The increase of peak systolic myocardial velocity from baseline to low dose dobutamine was significantly different between segments defined as normal, viable, and nonviable by 2-D DSE (2.71 +/- 1.91 cm/sec, 1.86 +/- 2.15 cm/sec, and 0.99 +/- 1.16 cm/sec, respectively; P < 0.001). The increase of peak systolic myocardial velocity from rest to low dose dobutamine for normal, mismatch, and match segments defined by PET was 2.72 +/- 1.96, 1.01 +/- 0.96 and 0.80 +/- 1.07 cm/sec, respectively (P < 0.001). In conclusion, the increase of peak systolic myocardial velocity during low dose dobutamine stimulation determined by pulsed TDI distinguishes between different myocardial viability states. It complements the standard interpretation of stress echocardiograms.

Aged↗
PubMed2001

Tissue tracking allows rapid and accurate visual evaluation of left ventricular function.

AIMS: To evaluate the ability of tissue tracking for rapid assessment of left ventricular function by determination of the systolic mitral annular displacement. Tissue tracking is a new echocardiographic modality based on Doppler Tissue imaging allowing rapid visual assessment of the systolic baso-apical displacement of each myocardial segment in apical views by a graded colour display. METHODS AND RESULTS: We studied 90 patients (69 male, age 60.4 +/- 10.1 years) with different left ventricular function (25 subjects with normal left ventricular function, 25 patients with homogeneous depression of left ventricular function and 40 patients with prior myocardial infarction). Systolic mitral annular displacement was determined by tissue tracking and M-mode echocardiography. Apical two-, three- and four-chamber views were used to determine the mitral annular displacement of six sites. Left ventricular ejection fraction was determined by two-dimensional echocardiography using Simpson's rule. Tissue tracking was possible in all patients. In the 50 patients with normal left ventricular function or homogeneous depression of left ventricular function, mean mitral annular displacement correlated closely with mitral annular displacement determined by M-mode (r=0.99,P <0.001) and with left ventricular ejection fraction (r=0.97, P<0.001). Left ventricular ejection fraction < or = 30% could be predicted with a sensitivity of 98% and a specificity of 78% using a cut-off value of 4.8mm for the mitral annular displacement determined by tissue tracking. In patients with prior myocardial infarction correlation between the mean mitral annular displacement and left ventricular ejection fraction was lower (r=0.87, P<0.001). CONCLUSION: Systolic mitral annular displacement determined by tissue tracking correlates closely with mitral annular displacement determined by M-mode and with left ventricular ejection fraction. Thus, tissue tracking allows rapid semiquantitative evaluation of global left ventricular function by assessment of systolic mitral annular displacement.

Aged↗
PubMed2001

HOPE fixation: a novel fixing method and paraffin-embedding technique for human soft tissues.

We have developed a novel method for tissue fixation, including subsequent paraffin-embedding and sectioning, that allows the complete pathological analysis of all types of human soft tissues. Furthermore, it maintains additional positive features relevant to immunohistochemistry and molecular pathology. The so-called HOPE-technique (Hepes-Glutamic acid buffer mediated Organic solvent Protection Effect) comprises a protection-solution with an organic buffer, acetone as the only dehydrating agent, and pure paraffin of 52-54 degrees C melting temperature. Although the exact mechanism of protection has still to be elucidated, it seems rather unlikely that chemical bindings occur during the whole process of fixation, which is described and compared with the standard formalin-paraffin technique. Essentially, HOPE-fixed sections show formalin-like morphology. However, the sections are somewhat difficult to handle because of their fragility. This is due to the absence of any type of protein cross-linking and the dynamic processes of immersion and outflow of the HOPE protection solution. HOPE-fixed sections provide an excellent preservation of proteins and antigenic structures for differential analysis by immunohistochemical and/or enzyme histochemical techniques. However, their most remarkable feature is the extremely low degradation of nucleic acids (DNA and RNA) combined with good results obtained by in situ hybridization techniques. In conclusion, HOPE fixation may become a valuable additional tool in modern pathology.

Cross-Linking Reagents↗
PubMed2001

EnVision+, a new dextran polymer-based signal enhancement technique for in situ hybridization (ISH).

Seventy paraffin-embedded cervical biopsy specimens and condylomata were tested for the presence of human papillomavirus (HPV) by conventional in situ hybridization (ISH) and ISH with subsequent signal amplification. Signal amplification was performed either by a commercial biotinyl-tyramide-based detection system [GenPoint (GP)] or by the novel two-layer dextran polymer visualization system EnVision+ (EV), in which both EV-horseradish peroxidase (EV-HRP) and EV-alkaline phosphatase (EV-AP) were applied. We could demonstrate for the first time, that EV in combination with preceding ISH results in a considerable increase in signal intensity and sensitivity without loss of specificity compared to conventional ISH. Compared to GP, EV revealed a somewhat lower sensitivity, as measured by determination of the integrated optical density (IOD) of the positively stained cells. However, EV is easier to perform, requires a shorter assay time, and does not raise the background problems that may be encountered with biotinyl-tyramide-based amplification systems. (J Histochem Cytochem 49:1067-1071, 2001)

Cervix Uteri↗