H Hecker

Hannover Medical School, Hanover, Lower Saxony, Germany

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Publications (202)995.88 Total impact

  • Karin Weissenborn · Hartmut Hecker · Norbert Rückert

    No preview · Article · Jan 2015 · Gastroenterology
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    ABSTRACT: Background and Aims: While central nervous system complications (CNSc) are common after liver transplantation (OLT), standardised prospective studies are still lacking. Methods: This prospective study aims to determine the incidence of CNSc, to describe clinical presentations and to establish predicting factors of CNSc. One-hundred-thirty-six adult patients who underwent OLT at Hannover Medical School between December 2008 and June 2011 were included. Weekly examinations were performed by a neurologist during their hospital stay after OLT. Patient data, donors data, operative and postoperative variables were collected. Patients with cerebral dysfunction after OLT underwent diagnostic work-up including brain imaging and if necessary cerebrospinal fluid (CSF) analysis. Patients with CNS symptoms but negative imaging and CSF results and patients with pontine myelinolysis or posterior reversible encephalopathy syndrome (PRES) were subsumed as metabolic-toxic CNSc, those with stroke, intracranial haemorrhage or central nervous system (CNS) infection as non-metabolic CNSc. Multiple regression analysis was used to identify independent risk factors for the development of metabolic-toxic CNSc. Results: Forty-four (32.8%) patients developed CNSc, thereof 37 (27.6%) metabolic-toxic and 7 (5.2%) non-metabolic CNSc. Acute-on-chronic liver failure, number of subsequent surgeries, and primary sclerosing cholangitis were identified as independent predictors for the development of metabolic-toxic CNSc. Metabolic-toxic CNSc was associated with prolonged hospital stay and non-metabolic with higher mortality. Conclusions: CNSc are common and relevant complications after OLT. Patients after OLT, especially with risk factors, should undergo regular standardized neurological examination that would allow early detection of these complications. Liver Transpl , 2014. © 2014 AASLD.
    No preview · Article · Nov 2014 · Liver Transplantation

  • No preview · Article · Sep 2014 · The Thoracic and Cardiovascular Surgeon
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    ABSTRACT: Background & Aims: Patients after orthotopic liver transplantation (OLT) may show cognitive dysfunction.To date it is not clear if these dysfunction are residuals from hepatic encephalopathy (HE) or new-onset cognitive disturbances. Just as little is known about the course and clinical significance.Methods: In this prospective observational study 50 patients from the waiting list for OLT were examined in outpatient setting before OLT, and 6 and 12 months after OLT using the psychometric hepatic encephalopathy score (PHES), the Inhibitory Control Test (ICT), and the Critical Flicker Frequency (CFF) for the diagnosis of HE and in addition the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) as a tool for the measurement of global cognitive function. The Short Form Health Survey (SF-36) was used to assess health-related quality of life.Results: Twelve months after OLT cognitive dysfunction characteristic for HE had resolved but a secondary cognitive decline became apparent showing different features than known from HE. Seventy percent of the patients deteriorated in at least one cognitive domain of RBANS. Cognitive decline was neither related to a history of HE nor to a history of alcohol abuse, but was accompanied by decline in quality of life.Conclusion: OLT improves HE, but is frequently followed by new-onset cognitive dysfunction which interfere with quality of life. Liver Transpl , 2014. © 2014 AASLD.
    Preview · Article · Jul 2014 · Liver Transplantation
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    ABSTRACT: In the German Multicenter Erythropoietin (EPO) Stroke Trial, patients not receiving thrombolysis most likely benefited from EPO on clinical recovery, whereas a combination of rtPA and EPO was associated with increased mortality. We investigated whether the combination of rtPA and EPO increased release of the endogenous NO synthase inhibitor asymmetric dimethylarginine (ADMA), and thereby potentially deteriorated ischemic stroke outcome, as suggested from experimental data. ADMA was determined in serum samples from 90 patients of the German Multicenter EPO Stroke Trial taken at days 1 (within 6 hours after symptom onset), 2, 3, 4, and 7 after stroke using high-performance liquid chromatography-tandem mass spectrometry. ADMA was analyzed for the different treatment groups (EPO, n=25; placebo, n=30; rtPA+placebo, n=18; EPO+rtPA, n=17). Clinical outcome was expressed as difference between National Institutes of Health Stroke Scale at baseline and 90 days. ADMA levels significantly increased during the observation time in EPO, EPO+rtPA, and placebo groups (P<0.05). A treatment effect on ADMA levels was revealed by repeated measures ANOVA only in the rtPA+placebo group (P=0.027). Here, ADMA levels were decreased compared with the placebo group (P<0.05). Both the EPO and the rtPA+placebo groups in the Hannover subgroup of the EPO trial had better outcome than the placebo group (P<0.05). Our data underscore the potential benefit of EPO in ischemic stroke. The hypothesis from experimental data, that EPO treatment increases ADMA in stroke patients, was disproved. Further studies are needed to clarify whether decreased ADMA might contribute to therapeutic rtPA effects.
    Full-text · Article · Jun 2013 · Stroke
  • Mechthild M Gross · Cornelia Frömke · Hartmut Hecker
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    ABSTRACT: Purpose: The objective was to study the association of different timings of intrapartum interventions with labour duration and mode of birth. Methods: A longitudinal cohort study of 2,090 nulliparae and 1,873 multiparae with a singleton in cephalic presentation was conducted. We assessed the association between, on the one hand, the timing of augmentation with oxytocin, neuraxial analgesia and amniotomy, and, on the other hand, the time to complete dilatation, spontaneous or operative vaginal delivery or caesarean delivery, using a Cox regression model accounting for standard confounders. Results: From amniotomy onwards labour was accelerated. In multiparae, amniotomy was associated with an initial 6.6-fold acceleration, decreasing first stage duration until the hazard ratio reached around 3.5, where the intervention was performed 5 h after labour onset; thereafter, acceleration continued with a hazard ratio of around 3. In nulliparae, neuraxial analgesia was associated with a shorter first stage when administered between 7 and 11 h after labour onset; the later it was performed, the less likely was spontaneous birth and the more likely an operative vaginal birth in nulliparae or a caesarean section in multiparae. The start of oxytocin augmentation was associated with acceleration towards both full dilatation and caesarean section during first stage and an increased risk of operative vaginal birth during second stage. The later oxytocin augmentation started, the more likely it was that spontaneous birth would be retarded in multiparous women. Conclusions: Applying amniotomy, oxytocin and neuraxial analgesia at their optimal timing may improve the progress and outcome of labour.
    No preview · Article · Jun 2013 · Archives of Gynecology
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    ABSTRACT: Objective Hepatic encephalopathy (HE) is a common complication of liver insufficiency. While there is widespread acceptance of its importance, there is no consensus on how best to diagnose and monitor HE. Objective To compare the four most favoured methods for the diagnosis of HE. Design 170 patients who were on the waiting list for liver transplantation as well as 86 healthy controls were included in the study. All patients and controls underwent the portosystemic encephalopathy syndrome test yielding the psychometric hepatic encephalopathy score (PHES), the repeatable battery for the assessment of neuropsychological status (RBANS), the inhibitory control test (ICT) and critical flicker frequency (CFF) measurement. Results PHES and ICT targets had the best sensitivity (85.7% vs 85.7%) and specificity (96.5% vs 97.6%) for the diagnosis of overt HE. CFF showed inferior sensitivity (40.9%) for the diagnosis of HE and dependency from previous alcohol abuse (p=0.015). Multiple regression analysis showed that all test results apart from PHES were influenced by secondary diagnoses such as diabetes mellitus and renal insufficiency. Conclusions In the German population of patients awaiting liver transplantation, PHES is the most robust method for the diagnosis and follow-up of HE.
    No preview · Article · Jan 2013 · Gut
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    ABSTRACT: Background & aims: Extrapyramidal and cerebellar symptoms belong to the most prominent features of episodic hepatic encephalopathy, and usually decrease upon ammonia-lowering therapy. Rapidly progressing parkinsonian symptoms, which are unresponsive to treatment of hepatic encephalopathy, indicate cirrhosis-related Parkinsonism. This study aims at analyzing the prevalence of cirrhosis-related Parkinsonism in patients with liver cirrhosis, and to study the functional status of the striatal dopaminergic system in these patients. Methods: 214 patients with liver cirrhosis who were consecutively seen at the out-patient clinic for liver transplant candidates and/or at the transplantation wards at Hannover Medical School, between August 1, 2008 and March 31, 2011, underwent a standardized neurological examination while on the waiting list or immediately after liver transplantation. Single photon emission computer tomography (SPECT) using (123)I-beta-CIT, for the evaluation of the striatal dopamine transporter function, and (123)I-IBZM for the evaluation of the striatal dopamine D2 receptor availability, was performed in 6 patients with cirrhosis-related Parkinsonism. Results: Cirrhosis-related Parkinsonism was diagnosed in 9 of 214 patients (4.2%). SPECT revealed significantly decreased dopamine receptor availability in 5 of 6 patients studied, and significantly decreased dopamine transporter availability in 3. Levodopa improved motor dysfunction in two of four patients treated, although only temporarily. Incomplete recovery was observed in two patients after liver transplantation. Conclusions: Cirrhosis-related Parkinsonism is more frequent than presumed. The presented data suggest pre- and postsynaptic alteration of striatal dopaminergic neurotransmission as a possible cause of cirrhosis-related Parkinsonism and reveal the limited effects of dopaminergic therapy.
    No preview · Article · Dec 2012 · Journal of Hepatology
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    ABSTRACT: To describe the neurologic and neuroradiologic complications of Shiga toxin producing Escherichia coli infection (STEC)-associated hemolytic-uremic syndrome (HUS) in adults. All 52 adult patients with STEC O104:H4 infection cared for at Hannover Medical School during the outbreak in Germany through May-July 2011 are considered in this observational study. Forty-three of the 52 patients underwent a standard neurologic diagnostic procedure including clinical examination, Mini-Mental State Examination, and Glasgow Coma Scale Score. Thirty-six patients underwent EEG, and 26 had cerebral MRI, 9 of them repeatedly. Case records of 9 patients who had not been seen by a neurologist were analyzed retrospectively. Forty-eight of the 52 patients had HUS. All but 1 of these showed neurologic symptoms. Focal neurologic signs like double vision, difficulties in finding words, or hyperreflexia were present in 23, additional deficits in orientation, attention, memory, or constructive abilities in 9, and marked impairment of consciousness in 15. MRI showed brainstem, midbrain, thalamus, corpus callosum, and white matter lesions in half of the patients, predominantly in diffusion-weighted images. The extent of MRI lesions did not correlate with clinical symptoms. General slowing but no focal alteration was found in half of the patients examined by EEG. Our findings suggest a toxic-metabolic pathology behind the neurologic impairment instead of multiple infarction due to microthrombosis. Future studies should aim to clarify if early antibiotic therapy or bowel cleansing might help to decrease the rate of neurologic complications in STEC-HUS.
    Full-text · Article · Sep 2012 · Neurology
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    ABSTRACT: Pollen grains with a diameter of more than 10 μm preferentially deposit in the upper airways. Their contribution to lower airway inflammation is unclear. One hypothesis is that lower airway inflammation is mainly caused by allergen containing pollen starch granules, which are released from the pollen grains and can easily enter the peripheral airways because of their smaller size. To investigate the differential effect of pollen grains and pollen starch granules on nasal symptoms and lower airway inflammation. In a 2-period crossover design, 30 patients with allergic rhinitis and mild intermittent asthma underwent 2 allergen challenges on consecutive days in an environmental challenge chamber with either a mixture of pollen grains plus starch granules or starch granules only. End points were the total nasal symptom score (TNSS), nasal secretion weight, nasal flow, spirometry, and exhaled nitric oxide (eNO). The presence of pollen grains had a significant and considerable effect on increase in TNSS and secretion weight and on decrease in nasal flow. Starch granules alone only had minimal effects on nasal symptoms. Challenges with starch granules significantly increased eNO. Pollen had no effect on eNO. Pollen grains cause nasal symptoms but do not augment lower airway inflammation, whereas starch granules trigger lower airway inflammation but hardly induce nasal symptoms.
    No preview · Article · Sep 2012 · Annals of allergy, asthma & immunology: official publication of the American College of Allergy, Asthma, & Immunology
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    ABSTRACT: To evaluate whether contrast enhanced ultrasound (CEUS) might also be used for response prediction and early response evaluation in patients receiving bevacizumab based chemotherapy for metastasized colorectal cancer. Thirty consecutive patients with non primary resectable liver metastases from colorectal cancer underwent CEUS before treatment (CEUS date 1) and before the second (CEUS date 2) and fourth (CEUS date 3) cycle of bevacizumab based chemotherapy. Three parameters [PEAK, Time to peak (TTP) and RISE RATE]were correlated with radiological response. For neoadjuvant purpose a reduction of tumour mass was required to assume clinical response. Based on these response criteria there was a significant (P < 0.001) correlation in TTP between metastases of responders (9.08 s) and non-responders (14.76 s) archived on CEUS date 1. By calculating a standardized quotient (metastases divided by normal liver tissue) we were able to define a cut off, predicting response with a sensitivity of 92.3 % and a specificity of 100 %. To reflect a palliative intention only those patients with progressive disease were classified as non-responders. In this stetting TTP was also significantly (P < 0.01) different between responders and non-responders. In contrast, Peak and Rise rate did not show any significant difference between responder and non-responder. CEUS might serve as a surrogate marker to predict treatment response in patients with metastasized colorectal cancer who receive antiangiogenic therapy.
    Preview · Article · Feb 2012 · World Journal of Gastroenterology
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    ABSTRACT: Matrix metalloproteinase-9 (MMP-9) represents a promising marker for acute stroke management. In clinical studies MMP-9 has been quantified by ELISA using differing protocols. We aimed to establish a valid protocol by evaluation of preanalytics. Blood from stroke patients (n=28) and healthy controls (n=28) was drawn into tubes containing different anticoagulants (EDTA, citrate, lithium-heparin (heparin) and heparin with proteinase inhibitors) and processed after 0, 60 and 240 min. MMP-9 plasma protein and mRNA from mononuclear leukocytes were determined. In regard to anticoagulants used, samples showed different MMP-9 protein baseline values and kinetics. Stable MMP-9 protein concentrations were only measured from EDTA samples. Particularly in samples with proteinase inhibitors protein and mRNA concentrations increased over time. Kinetics did not differ between patients and controls. Preanalytics plays a key role for determination of MMP-9. EDTA seems to be a valid anticoagulant for MMP-9 protein measurement.
    No preview · Article · Feb 2012 · Clinical biochemistry
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    ABSTRACT: Recent studies have shown that narrow-band imaging (NBI) is a powerful diagnostic tool for the differentiation between neoplastic and non-neoplastic colorectal polyps. To develop a computer-based method for classification of colorectal polyps. A prospective study. University hospital. A total of 214 patients with colorectal polyps who underwent a zoom NBI colonoscopy. A total of 434 detected polyps 10 mm or smaller were imaged and subsequently removed for histological analysis. Diagnostic performance in polyp classification by 2 experts, 2 nonexperts, and a computer-based algorithm. The expert group and the computer-based algorithm achieved a comparable diagnostic performance (expert group: 93.4% sensitivity, 91.8% specificity, and 92.7% accuracy; computer-based algorithm: 95.0% sensitivity, 90.3% specificity, and 93.1% accuracy) and were both significantly superior to the nonexpert group (86.0% sensitivity, 87.8% specificity, and 86.8% accuracy) in terms of sensitivity, negative predictive value, and accuracy. Subgroup analysis of 255 polyps 5 mm or smaller revealed comparable results without significant differences in the overall analysis of all polyps. No fully automatic classification system. The study demonstrates that computer-based classification of colon polyps can be achieved with high diagnostic performance.
    No preview · Article · Dec 2011 · Gastrointestinal endoscopy
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    ABSTRACT: The diagnosis of uraemic encephalopathy is considered if patients with end-stage renal disease present with neuropsychiatric symptoms. However, cognitive deficits may occur in patients with chronic kidney disease (CKD) long before any overt neurological symptoms can be observed. We hypothesized that cognitive dysfunction in patients with CKD both, treated and untreated by haemodialysis, may correspond to metabolic changes in distinct brain regions. We performed magnetic resonance spectroscopy (MRS) ((1)H-MRS) of the brain in 23 non-dialysed patients with CKD (Stages 4-5) and in 15 haemodialysed patients. Healthy controls (n = 63) adjusted for age and education were recruited from the social environment of the patients' population. Attention, learning and memory were assessed by psychometric testing. MRS alterations were predominantly found in the white matter. Concentrations of creatine-containing compounds (Cr) were decreased in dialysed and non-dialysed patients. Choline concentration (Cho) and combined N-acetylaspartate and N-acetylaspartylglutamate concentration (NAx) were reduced only in dialysed patients. Disturbance in memory and learning ability as well as attention deficits were observed in both patient groups. Of note, attention deficits were more severe in dialysed patients. MRS results correlated with attention deficits in dialysed patients. CKD patients without clinical signs of uraemic encephalopathy showed metabolic disturbances in distinct brain regions as well as cognitive impairments. Haemodialysis was accompanied with more severe cognitive dysfunction and metabolic alternations than CKD alone. Although the small sample size limits the interpretation of the data, a negative impact of haemodialysis on cognitive function must be considered.
    Preview · Article · Jul 2011 · Nephrology Dialysis Transplantation
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    ABSTRACT: Patients with hepatitis C virus (HCV) infection frequently show neuropsychiatric symptoms. This study aims to help clarify the neurochemical mechanisms behind these symptoms and to add further proof to the hypothesis that HCV may affect brain function. Therefore, 15 patients who reported increasing chronic fatigue, mood alterations, and/or cognitive decline since their HCV infection underwent neurologic and neuropsychological examination, magnetic resonance imaging, (18)F-fluoro-deoxy-glucose positron emission tomography of the brain, and single photon emission tomography of striatal dopamine and midbrain serotonin transporter (SERT) availability. None of the patients had liver cirrhosis. Patients' data were compared with data of age-matched controls. In addition, regression analysis was performed between cognitive deficits, and mood and fatigue scores as dependent variables, and cerebral glucose metabolism, dopamine, or SERT availability as predictors. Patients showed significant cognitive deficits, significantly decreased striatal dopamine and midbrain SERT availability, and significantly reduced glucose metabolism in the limbic association cortex, and in the frontal, parietal, and superior temporal cortices, all of which correlated with dopamine transporter availability and psychometric results. Thus, the study provides further evidence of central nervous system affection in HCV-afflicted patients with neuropsychiatric symptoms. Data indicate alteration of dopaminergic neurotransmission as a possible mechanism of cognitive decline.
    Full-text · Article · Jun 2011 · Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism
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    ABSTRACT: An environmental challenge chamber (ECC) is a useful tool to expose allergic patients to relevant allergens in a controlled indoor setting and to test anti-allergic treatment. Hitherto, ECC studies with grass pollen are conducted primarily outside of the pollen season to avoid the influence of natural pollen exposure. To investigate whether an established anti-allergic treatment, a combination of cetirizine (CET) and pseudoephedrine (PSE), shows an equivalent treatment effect within and outside of the grass pollen season when tested in an ECC. In a randomized, placebo-controlled, double-blind, four-way crossover study, the effect of a combination of 10 mg CET and 120 mg PSE compared with placebo on nasal symptoms, nasal flow, and nasal secretion was investigated in 70 patients with seasonal allergic rhinitis. Subjects underwent four 6-hour pollen challenges in an ECC with administration of the drugs after 2 hours. Two challenges were conducted within the grass pollen season and two out of the grass pollen season. The active treatment significantly improved nasal symptoms and nasal flow and significantly reduced the amount of nasal secretion compared with placebo both within and outside of the pollen season (P < .0001 each). The treatment effect was not different between the seasons (P > .05). Controlled allergen provocation in an ECC can be used to test anti-allergic treatment both within and outside of the grass pollen season.
    No preview · Article · Apr 2011 · Annals of allergy, asthma & immunology: official publication of the American College of Allergy, Asthma, & Immunology
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    ABSTRACT: Outcome of patients with hepatocellular carcinoma is influenced by their histological grade. Invasive biopsy of the lesions is the gold standard in this regard. We therefore analysed the diagnostic accuracy of contrast enhanced ultrasound for non-invasive grading of hypervascular hepatocellular carcinoma in liver cirrhosis. According to the tumour perfusion kinetics on contrast enhanced ultrasound two grading groups were prospectively defined: well-differentiated hepatocellular carcinoma (US-G1) and higher grade hepatocellular carcinoma (US-G2/G3). Immediately after contrast enhanced ultrasound-grading, biopsies of hepatocellular carcinoma-lesions (n=95, 1.2-12.5 cm) were obtained and analysed for tumour grading (G). Descriptive statistics, sensitivity, specificity positive and negative predictive values, diagnostic likelihood ratios and interoperator reproducibility were calculated (κ). Histologically 77 (81.1%) patients had G2-G3 and 18 (18.9%) had G1 tumours. Higher grade hepatocellular carcinoma showed more often a washout in the portal or late phase (p<0.0001). The sensitivity, specificity, positive predictive values and negative predictive values of contrast enhanced ultrasound for grading of hepatocellular carcinoma for all patients were 94% (CI: 72-99%), 95% (CI: 88-99%), 81% and 99% and for patients with tumours<5 cm 100%(95% CI: 79-100), 96% (95% CI: 80-99), 92% and 100%. Positive and negative diagnostic likelihood ratios' were 18 and 26 and 0.06 and 0, respectively. κ=0.941 (p<0.001). Contrast enhanced ultrasound has a high diagnostic value and reproducibility for non-invasive grading of hypervascular hepatocellular carcinoma >1cm in patients with liver cirrhosis.
    Full-text · Article · Mar 2011 · Digestive and Liver Disease
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    ABSTRACT: To describe the timing and frequency of interventions during labour, and in addition to compare the timings of the interventions against the partogram action lines. Longitudinal prospective and retrospective cohort study. 47 Hospitals in Lower Saxony, Germany. 3963 Births of nulliparae and multiparae with singletons in vertex presentation giving birth between April and October 2005. The participation rate for the prospectively recruited sample (n = 1169) was 4.7%. Time intervals until intrapartal interventions were calculated by Kaplan-Meiers estimation. Outcome variables were duration of labour and mode of birth. Multiparae had slightly longer median time intervals between the onset of labour and the beginning of care by the midwife than nulliparae. With regard to the intervals between the onset of labour and the occurrence of interventions, multiparae had shorter median durations than nulliparae in respect of amniotomy, oxytocin augmentation and neuraxial analgesia. By three hours after onset of labour 8.4% of nulliparae had received oxytocin augmentation, 10.7% neuraxial analgesia and 8.9% an amniotomy. Of multiparae, 9.1% had received oxytocin augmentation but only 5.6% neuraxial analgesia; 20.0% had had an amniotomy. The median time interval before the initiation of water immersion and massage was between three and four hours; that before the initiation of vertical positioning was 1.8 hours. Current German practice without the use of partogram action lines reveals that early interventions were performed before the partogram action lines were met. Interventions applying midwifery care techniques such as vertical positioning preceded more invasive medical interventions during the process of childbirth.
    Full-text · Article · Dec 2010 · Midwifery
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    ABSTRACT: Radiation therapy to the mediastinum and breast can be associated with cardiac complications. Cardiac damage may manifest early during radiation therapy or occur late, years after radiation therapy has been finished. Myocardial damage is associated with the release of both troponin I (TnI) and brain natriuretic peptide (BNP). The current study sought to determine whether radiation treatment to the mediastinum and breast leads to the release of cardiac biomarkers. The study comprised 23 patients: 18 with lung cancer and 5 with breast cancer. Radiation therapy was performed for up to 6 weeks. Total radiation dose was >45 Gy in each patient with a dose of 1.8 Gy per fraction. Blood samples to determine TnI and BNP were taken before and once a week during radiation therapy. Echocardiography was done before and after radiation had been finished. Two patients died during the study. Both TnI and BNP levels increased significantly during the study (log(10) scale); however, absolute and mean values remained on a relatively low level (mean preradiation and postradiation TnI: 0.007 +/- 0.008, 0.014 +/- 0.01 ng/ml; mean preradiation and postradiation BNP: 123 +/- 147, 159 +/- 184 pg/ml). Radiation therapy leads to cardiac cell damage and changes in the left ventricular loading conditions as suggested by a significant increase of the cardiac biomarkers TnI and BNP. Determination of serum levels seems to be superior to echocardiography in detecting radiation-induced cardiac damage. Serial measurements of cardiac biomarkers may facilitate the management of patients undergoing radiation therapy and may help to define subgroups at high risk of developing heart failure.
    No preview · Article · May 2010 · Chemotherapy
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    ABSTRACT: Recent studies have shown that narrow-band imaging (NBI) is a powerful diagnostic tool for differentiating between neoplastic and nonneoplastic colorectal polyps. The aim of the present study was to develop and evaluate a computer-based method for automated classification of colorectal polyps on the basis of vascularization features. In a prospective pilot study with 128 patients who were undergoing zoom NBI colonoscopy, 209 detected polyps were visualized and subsequently removed for histological analysis. The proposed computer-based method consists of image preprocessing, vessel segmentation, feature extraction, and classification. The results of the automated classification were compared to those of human observers blinded to the histological gold standard. Consensus decision between the human observers resulted in a sensitivity of 93.8 % and a specificity of 85.7 %. A "safe" decision, i. e., classifying polyps as neoplastic in cases when there was interobserver discrepancy, yielded a sensitivity of 96.9 % and a specificity of 71.4 %. The overall correct classification rates were 91.9 % for the consensus decision and 90.9 % for the safe decision. With ideal settings the computer-based approach achieved a sensitivity of approximately 90 % and a specificity of approximately 70 %, while the overall correct classification rate was 85.3 %. The computer-based classification showed a specificity of 61.2 % when a sensitivity of 93.8 % was selected, and a 53.1 % specificity with a sensitivity of 96.9 %. Automated classification of colonic polyps on the basis of NBI vascularization features is feasible, but classification by observers is still superior. Further research is needed to clarify whether the performance of the automated classification system can be improved.
    No preview · Article · Mar 2010 · Endoscopy

Publication Stats

7k Citations
995.88 Total Impact Points


  • 1987-2014
    • Hannover Medical School
      • • Institute for Biometry
      • • Department of Gastroenterology, Hepatology and Endocrinology
      • • Department of Cardiology and Angiology
      Hanover, Lower Saxony, Germany
  • 2002
    • University of Tuebingen
      • Department of Paediatric Surgery
      Tübingen, Baden-Württemberg, Germany
  • 2000
    • University of Oxford
      Oxford, England, United Kingdom