Juergen F Schaefer

Universitätsklinikum Tübingen, Tübingen, Baden-Württemberg, Germany

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Publications (77)156.56 Total impact

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    ABSTRACT: Objectives: The aim of this study was to evaluate combined 2D and 3D dynamic MR urography with respiratory compensation in children with anomalies of the genitourinary tract, allowing for computation of split renal function and assessment of urinary tract obstruction. Methods: Dynamic MR urography was performed in 53 children (3mo to 16y) with anomalies of the urinary tract. A protocol for dynamic MR urography and nephrography was implemented at 1.5T using a navigator triggered 2D TurboFLASH sequence. Split renal function and contrast-medium excretion were assessed after bolus injection of 0.05 mmol/kg body weight gadolinium dimeglumine. In the excretory phase, a 3D gradient-echo data set with high spatial resolution was acquired. In all patients, MAG3 scintigraphy was obtained as a reference standard. Results: In all children, dynamic MR nephrography and urography could be performed with excellent compensation of breathing artifacts providing region-of-interest analysis in nearly identical kidney position. The assessment of contrast-medium excretion into the ureter allowed for discrimination of functional from non-functional stenosis. Split renal function assessed by MRI showed an excellent agreement with the MAG3 reference standard with a correlation coefficient r=0.95. Additionally recorded 3D data sets offered good depiction of anatomical anomalies in all patients. Conclusions: The proposed protocol provides a robust technique for assessment of ureteral obstruction and split renal function with compensation of breathing artifacts, short post-processing time, and excellent 3D spatial resolution. Advances in Knowledge: The combined protocol of 2D and 3D MR urography is an efficient technique for assessment of renal morphology and function.
    The British journal of radiology. 10/2014;
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    ABSTRACT: Purpose To compare positron emission tomography (PET)/magnetic resonance (MR) imaging and PET/computed tomography (CT) for lesion detection and interpretation, quantification of fluorine 18 ((18)F) fluorodeoxyglucose (FDG) uptake, and accuracy of MR-based PET attenuation correction in pediatric patients with solid tumors. Materials and Methods This prospective study had local ethics committee and German Federal Institute for Drugs and Medical Devices approval. Written informed consent was obtained from all patients and legal guardians. Twenty whole-body (18)F-FDG PET/CT and (18)F-FDG PET/MR examinations were performed in 18 pediatric patients (median age, 14 years; range, 11-17 years). (18)F-FDG PET/CT and (18)F-FDG PET/MR data were acquired sequentially on the same day for all patients. PET standardized uptake values (SUVs) were quantified with volume of interest measurements in lesions and healthy tissues. MR-based PET attenuation correction was compared with CT-derived attenuation maps (µ-maps). Lesion detection was assessed with separate reading of PET/CT and PET/MR data. Estimates of radiation dose were derived from the applied doses of (18)F-FDG and CT protocol parameters. Descriptive statistical analyses were performed to report correlation coefficients and relative deviations for comparison of SUVs, rates of lesion detection, and percentage reductions in radiation dose. Results PET SUVs showed strong correlations between PET of PET/CT (PETCT) and PET of PET/MR (PETMR) (r > 0.85 for most tissues). Apart from drawbacks of MR-based PET attenuation correction in osseous structures and lungs, similar SUVs were found on PET images corrected with CT-based µ-maps (13.1% deviation of SUVs for bone marrow and <5% deviation for other tissues). Lesion detection rate with PET/MR imaging was equivalent to that with PET/CT (61 areas of focal uptake on PETMR images vs 62 areas on PETCT images). Advantages of PET/MR were observed especially in soft-tissue regions. Furthermore, PET/MR offered significant dose reduction (73%) compared with PET/CT. Conclusion Pediatric oncologic PET/MR is technically feasible, showing satisfactory performance for PET quantification with SUVs similar to those of PET/CT. Compared with PET/CT, PET/MR demonstrates equivalent lesion detection rates while offering markedly reduced radiation exposure. Thus, PET/MR is a promising modality for the clinical work-up of pediatric malignancies. © RSNA, 2014 Online supplemental material is available for this article.
    Radiology 05/2014; · 6.34 Impact Factor
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    ABSTRACT: Purpose: The aim of this study was to investigate frequencies of typical artifacts in low-dose pediatric lung examinations using high-pitch computed tomography (HPCT) compared to MDCT, and to estimate the effective radiation dose (Eeff). Materials and Methods: Institutional review board approval for this retrospective study was obtained. 35 patients (17 boys, 18 girls; mean age 112 ± 69 months) were included and underwent MDCT and follow-up scan by HPCT or vice versa (mean follow-up time 87 days), using the same tube voltage and current. The total artifact score (0 - 8) was defined as the sum of artifacts arising from movement, breathing or pulsation of the heart or pulmonary vessels (0 - no; 1 - moderate; 2 - severe artifacts). Eeff was estimated according to the European Guidelines on Quality Criteria for Multislice Computed Tomography. The Mann-Whitney U test was used to analyze differences between the patient groups. The Spearman's rank correlation coefficient was used for correlation of ordinal variables. Results: The scan time was significantly lower for HPCT compared to MDCT (0.72 ± 0.13 s vs. 3.65 ± 0.81s; p < 0.0001). In 28 of 35 (80 %) HPCT examinations no artifacts were visible, whereas in MDCT artifacts occurred in all examinations. The frequency of pulsation artifacts and breathing artifacts was higher in MDCT compared to HPCT (100 % vs. 17 % and 31 % vs. 6 %). The total artifact score significantly correlated with the patient's age in MDCT (r = - 0.42; p = 0.01), but not in HPCT (r = - 0.32; p = 0.07). The estimated Eeff was significantly lower in HPCT than in MDCT (1.29 ± 0.31 vs. 1.47 ± 0.37 mSv; p < 0.0001). Conclusion: Our study indicates that the use of HPCT has advantages for pediatric lung imaging with a reduction of breathing and pulsation artifacts. Moreover, the estimated Eeff was lower. In addition, examinations can be performed without sedation or breath-hold without losing image quality. Key points: • Fewer artifacts in pediatric lung imaging with HPCT• Reduced Eeff in HPCT• HPCT without sedation or breath-hold without loss of image quality Citation Format: • Tsiflikas I, Thomas C, Ketelsen D et al. High-Pitch Computed Tomography of the Lung in Pediatric Patients: An Intraindividual Comparison of Image Quality and Radiation Dose to Conventional 64-MDCT. Fortschr Röntgenstr 2014; DOI: 10.1055/s-0034-1366426.
    RöFo - Fortschritte auf dem Gebiet der R 04/2014; · 2.76 Impact Factor
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    ABSTRACT: This workshop was held a year after the initial positron emission tomography/magnetic resonance (PET/MR) workshop in Tübingen, which was recently reported in this journal. The discussions at the 2013 workshop, however, differed substantially from those of the initial workshop, attesting to the progress of combined PET/MR as an innovative imaging modality. Discussions were focused on the search for truly novel, unique clinical and research applications as well as technical issues such as reliable and accurate approaches for attenuation and scatter correction of PET emission data. The workshop provided hands-on experience with PET and MR imaging. In addition, structured and moderated open discussion sessions, including six dialogue boards and two roundtable discussions, provided input from current and future PET/MR imaging users. This summary provides a snapshot of the current achievements and challenges for PET/MR.
    Molecular imaging and biology: MIB: the official publication of the Academy of Molecular Imaging 03/2014; · 2.47 Impact Factor
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    ABSTRACT: During recent years, minimally invasive surgery (MIS) has become the standard approach for various operations in infants and children. This also holds true for surgery in children with solid tumors. Meanwhile, more and more oncological biopsies and resections are being performed laparoscopically or thoracoscopically. Despite its increasing role in pediatric tumor surgery, the different national and international multicenter trial groups have not yet implemented MIS within guidelines and recommendations in most of the current treatment protocols. An increasing number of reports describe a potential role of MIS in the different entities of pediatric surgical oncology. Over the time, there has been a diverse development of this approach with regard to the different neoplasms. The aim of this article is to give an overview and to describe the current state of the art of MIS in pediatric solid tumors.
    Frontiers in Pediatrics 01/2014; 2:48.
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    ABSTRACT: Surgical approach to children with complicated ureteral duplication is discussed controversially. Our aim was to determine the outcome of children with complicated renal duplication undergoing a single-stage surgical approach with laparoscopic partial nephrectomy and open bladder reconstruction. Data of patients from 2004 to 2008 were investigated retrospectively. Outcome was analyzed in terms of postoperative course, renal function, urinary tract infection and functional voiding. Thirteen patients were treated with laparoscopic partial nephrectomy and reconstruction of the lower urinary tract in a single-stage approach. Median age at operation was 15 months (2-63 m). One girl had a renal triplication. 7/13 patients presented with an ectopic ureterocele, two with an ectopic ureter, severe vesicoureteral reflux occurred in 6 patients. All patients had non-functioning renal moieties. Mean operative time was 239 min (129-309; SD 50). One re-operation was necessary 4 years after primary surgery due to a pole remnant. All patients had uneventful recoveries without evidence of recurrent UTI. Postoperative 99mTc-MAG3 scans showed no significant reduction of partial renal function (p = 0.4), and no signs of obstruction (p = 0.188). During a median follow-up of 60 months (49-86), dysfunctional voiding occurred in one patient. In children with complicated ureteral duplication a definitive single-stage procedure is feasible and shows excellent functional results.
    Pediatric Surgery International 09/2013; · 1.22 Impact Factor
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    ABSTRACT: We describe a 99-day old girl with inspissated bile syndrome (IBS) unresponsive to treatment with oral ursodeoxycholic acid. We performed a pure laparoscopic 2-stage procedure, consisting of cholecystostomy and insertion of an indwelling balloon catheter for local ursodeoxycholic acid flushing for 13 consecutive days. Subsequently, the cholecystostomy was removed, preserving the gallbladder using the same laparoscopical approach when bilirubin values returned to normal and bile duct obstruction was no longer detectable radiologically. This is the first report of an exclusively laparoscopic management of IBS.
    Journal of Pediatric Surgery 12/2012; 47(12):e47-e50. · 1.38 Impact Factor
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    ABSTRACT: PURPOSE CT has established in evaluation of pathological changes of lung parenchyma, particularly with regard to tumor staging, detection of bronchial anomalies, recurrent infections, cystic fibrosis and trauma. Despite all technological development of CT over the last decade, there is still need for sedation or even controlled ventilation in infants and uncooperative children for imaging. Aim of this study was to evaluate a new high-pitch scanning technique that makes breath-hold and sedation unnecessary. METHOD AND MATERIALS 35 consecutive patients (17 boys; mean age 112 ± 69 months) who underwent conventional MDCT (pitch 1.2) as well as high-pitch DSCT (HPCT) (pitch 3.0) of the lung with an average interval of 101 days between November 2009 and November 2011 were included in our study. None of the children received sedation. Children under the age of 6 years were examined in free breathing. Settings for tube current and voltage were identically for both scanning methods according to a weight-adapted, low-dose protocol (30-40 mAs;100-120 kVp). All images were evaluated by 2 senior radiologists in consensus. Image quality was rated in an intraindividual approach regarding following criteria: motion, breathing and pulsation artifacts as well as resolution of detail. Further effective radiation dose of both examinations was calculated from the DLP. RESULTS All examinations were completed without complications. HPCT results in a superior image quality compared to MDCT, because of reduction of breathing artifacts(HPCT n=1 vs. MDCT n=9) and in particular pulsation artifacts next to heart/mediatinum(HPCT n=7 vs. MDCT n=34), respectively next to pulmonary vessels(HPCT n=2 vs. MDCT n=24). Motion artifacts were not detected in both scanning techniques. Estimated effective radiation dose was on average 15% lower in HPCT(1,47 ± 0,71 mSv) compared to MDCT(1,61 ± 0,82 mSv). CONCLUSION High-pitch DSCT of the lung improves image quality compared to conventional MDCT, due to a significant decrease in breathing and pulsation artifacts. Furthermore examinations can be performed without sedation or breath-hold, even in infants and uncooperative children. In addition estimated radiation exposure is lower compared to conventional MDCT. CLINICAL RELEVANCE/APPLICATION High-pitch DSCT of the lung should be performed in children and infants were applicable, providing high image quality without the need for sedation or breath-hold.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: Background: It would be beneficial to establish pulmonary MRI as a complementary approach to CT for direct visualization of mosaic perfusion, bullae, and emphysema in patients with cystic fibrosis. Objectives: The purpose of this study was to compare both modalities, CT and MRI, using the Helbich-Bhalla score with a special focus on reliable detection of a mosaic pattern. Methods: Out of 51 patients examined by MRI on a 1.5-Tesla system during a period of 2 years, 19 patients were scheduled for additional low-dose CT in a clinical context. The MRI protocol comprised a gradient echo (GRE) sequence with a very short echo time (TE = 0.8 ms) in inspiration and expiration, a 3-D GRE sequence in breath hold, and a fast spin echo sequence with respiration and ECG triggering. MDCT was carried out in inspiration and adapted to body weight using 100 or 120 kV, 30-60 mA, 1- and 3-mm slice thicknesses, as well as low and high kernels. Additionally incremental slices in 3 positions were recorded in expiration for distinct detection of air trapping. CT and MRI analyses were performed by two radiologic readers in consensus unaware of the clinical parameters. The Helbich-Bhalla score of both examinations was correlated. Mean difference and accordance were assessed in each category. Results: There was a strong correlation between CT and MRI (R = 0.87, p < 0.01). The mean Helbich-Bhalla score for CT was 12.2 (range 1-18) and for MRI it was 11.7 (range 2-19). The mean difference was 0.5 points. Besides this strong correlation for findings (bronchiectasis, mucus plugging, peribronchial thickening, and consolidation) with a prolonged T2 TE in MRI, we could also state a qualitative agreement of 95-100% in the categories with short T2 and low signal intensity in MRI as emphysema, bullae, and mosaic perfusion. Conclusions: These results suggest that in our patient group none of the relevant findings were missed by MR imaging and reading.
    Respiration 11/2012; · 2.92 Impact Factor
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    ABSTRACT: PURPOSE Simultaneous MR/PET is a new modality in oncologic imaging demonstrating comparable results to PET/CT in adults. However, the comparison of qualitative and quantitative results between both modalities has to be evaluated especially in children and juveniles. METHOD AND MATERIALS The ongoing study for juveniles was proved by our local ethic committee. Nine patients (mean age 14y, range 11 to 18y) suffering from various solid tumors with indication for PET/CT (Biograph mCT 128, Siemens) were subsequently examined in MR/PET (Biograph mMR, Siemens). As the tracer 18F-FDG injected for routine PET/CT (uptake time approx. 60 min) was also used for the MR/PET examination (uptake time approx. 110 min), no additional radiation dose was applied. A simultaneous acquisition of PET and MRI was carried out using a 3D FLASH sequence with Dixon-based fat-water separation for a segmentation-based PET attenuation correction map. Coronal whole-body STIR sequences and focused transversal T2 weighted images and DWI sequences were obtained additionally. Image quality and artifacts, standardized uptake values (SUV) in tumor and control regions using a VOI analysis were evaluated. RESULTS All MR/PET acquisitions were performed successfully in juveniles. Image quality of the MRI sequences was as good as with a standard 3 Tesla scanner. No artifacts on MRI by the PET detector could be recognized. The visual impressions of the PET images were similar between PET/CT and MR/PET. The median difference of SUVs (average) between MR/PET and PET/CT of the target regions were as follows: tumor -7 %, lung -22% , liver -21% , muscle 4% , bone marrow -5, blood pool – 28 % . In 3 cases (2 soft tissue tumors and 1 neuroblastoma) additional information were provided by higher soft tissue contrast of MRI and the use of DWI. CONCLUSION MR/PET is a robust and promising modality for juveniles with possible additional diagnostic information. Beside biological and kinetic effects of tracer distribution after uptake intervals the modality-specific differences between PET/CT and MR/PET like diverse methods of attenuation correction have to be kept in mind when using SUVs for quantitative analysis. CLINICAL RELEVANCE/APPLICATION MR/PET is a robust and promising modality for juveniles suffering from solid tumors with possible additional diagnostic information.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: Extrahepatic portal vein (PV) obstruction (EHPVO) is a rare disorder in early childhood with unknown incidence and mostly unknown etiology. In children with EHPVO, the hepatopedal flow of the mesenteric venous blood is hindered by an obstruction of the PV resulting in prehepatic portal hypertension. The curative treatment with a meso-Rex shunt connects the superior mesenteric vein to the left PV by a venous autograft. Despite good primary patency, reocclusion of a meso-Rex bypass and its treatment can be challenging. We present 2 patients with EHPVO with subtotal functional occlusion of a meso-Rex shunt treated by percutaneous interventions with short- and mid-term follow-up.
    Journal of Pediatric Surgery 09/2012; 47(9):e23-8. · 1.38 Impact Factor
  • Clinical Research in Cardiology 05/2012; 101(10):853-5. · 3.67 Impact Factor
  • Guido Seitz, Joerg Fuchs, Juergen F Schaefer, Steven W Warmann
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    ABSTRACT: Molecular imaging is a novel field in cancer research combining various in vivo imaging modalities with molecular biology. Different techniques such as magnetic resonance tomography (MRI), positron emission tomography (PET), optical imaging methods (bioluminescence, fluorescence), or combination of these are used in basic research as well as in patients in different tumor entities. In hepatoblastoma (HB), there are only few reports on molecular imaging methods in a preclinical (optical imaging) and clinical setting (PET, PET-CT). Unimprovable treatment outcomes of patients in advanced tumor stages require novel treatment approaches. Photodynamic diagnosis (PDD) and photodynamic therapy (PDT) are novel diagnostic and therapeutic tools. Photodynamic diagnosis allows in vitro and in vivo detection of tumor cells using their fluorescending behaviour. PDT is a novel anticancer treatment approach leading to tumor cell destruction via apoptosis. In hepatoblastoma, there are only few reports on in vitro and in vivo studies using this treatment modality. First results seem to be promising and further studies will be required to further evaluate these techniques and to transfer them into clinical settings. This paper reviews different modalities of molecular imaging, photodynamic diagnosis and photodynamic therapy in childhood hepatoblastoma.
    Frontiers in bioscience (Elite edition) 01/2012; 4:487-92.
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    ABSTRACT: Bilateral nephroblastoma involving the renal hilus represents a significant surgical challenge. Different operative strategies have been proposed for this condition. We analyzed the outcome of simultaneous bilateral partial nephrectomy for complex stage V nephroblastoma. We retrospectively analyzed patients with bilateral nephroblastoma involving the renal hilus operated on at our institution between 2002 and 2008. We assessed patient data and surgical and oncologic outcomes. We analyzed data from 5 patients with a median age of 27 months at surgery (range 13 to 58). Two children had additional pulmonary metastases. Patients were treated according to the International Society of Pediatric Oncology 2001/German Society of Pediatric Oncology and Hematology protocol. All children underwent synchronous bilateral nephron sparing surgery (longitudinal partial nephrectomy or enucleation) of the central tumors. Median operating time was 182 minutes (range 129 to 291), with vascular exclusion performed in 4 patients (7 to 25 minutes). Complications consisted of urinary leakage in 2 cases. Postoperative renal function was unimpaired in 4 patients and 1 patient had Wilms tumor/aniridia/genitourinary malformations/retardation syndrome with glomerulopathy. One patient with pulmonary metastases and blastemal histology had multiple pulmonary relapses and died due to pulmonary progressive disease. Four patients are alive without evidence of disease at a median followup of 45 months (range 44 to 73). Surgery for central stage V nephroblastoma is possible with good functional and oncologic outcomes. The single stage approach is safe, provided that operating and treating physicians have sufficient expertise with such conditions. The ultimate goal is to avoid tumor nephrectomy.
    The Journal of urology 08/2011; 186(4):1430-6. · 3.75 Impact Factor
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    ABSTRACT: Magnetic resonance imaging (MRI) and/or scintigraphy are commonly used for follow-up in children after treatment of acute osteomyelitis. Regularly, post-treatment imaging reveals pathological findings even if serum inflammatory parameters and clinical presentation are normal. We analyzed combined positron emission tomography and multislice computed tomography (PET/CT) for this condition. Six children received PET/CT after treatment of acute osteomyelitis. Post-treatment MRI had revealed suspicious residual and/or additional findings. All patients had physiological serum infection parameters and no clinical symptoms. Median patient age was 59.5 months (range, 48-156). No increased 18-Fluor-2-deoxy-D-glucose uptake was observed in 3 patients. In 3 patients, there was minimal activity at the site of infection, which, however, did not reach the presumed range of osteomyelitis. All children were taken off antibiotic medication. No clinical symptoms reoccurred in any of them, and repeatedly controlled serum infection parameters were all normal. Median follow-up was 33 months (range, 4-65). The PET/CT was superior to MRI in distinguishing between infection and reparative activity within the musculoskeletal system in selected children after acute osteomyelitis. The termination of antibiotic treatment for children after acute osteomyelitis seems justified when laboratory parameters as well as clinical presentation are normal, and PET/CT scan is unsuspicious.
    Journal of Pediatric Surgery 08/2011; 46(8):1550-6. · 1.38 Impact Factor
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    ABSTRACT: To assess lung perfusion in young patients with cystic fibrosis (CF) using an arterial spin labeling (ASL) technique. Perfusion imaging was performed in 5 healthy volunteers and 33 pediatric patients (13 ± 5 years) with CF using an ASL technique. Image quality was evaluated on a five-point scale (1 = excellent). Quantitative perfusion maps were calculated based on the modified Bloch equations. Perfusion differences between volunteers and CF patients and regional differences between lobes were analyzed using Student's t test. The association of perfusion values and forced expiratory volume in 1 s (FEV1) was analyzed using univariate regression analysis. Mean lung perfusion was 698 ± 67 ml/100g/min (range: 593-777 ml/100g/min) in volunteers and 526 ± 113 ml/100g/min (range: 346-724 ml/100g/min) in CF patients. Median image quality was 2 in volunteers and 3 in CF patients. In CF patients, significantly lower perfusion was observed in the upper lobes compared to healthy volunteers. Mean perfusion values significantly correlated with FEV1 (r = 0.84, P < 0.0001). ASL perfusion imaging provides lung perfusion assessment in young CF patients. This non-invasive functional imaging technique is worth being evaluated in the clinical monitoring of CF patients.
    MAGMA Magnetic Resonance Materials in Physics Biology and Medicine 07/2011; 25(2):155-62. · 1.86 Impact Factor
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    ABSTRACT: To demonstrate a rare case of urological pathology, we report a combination of a single kidney and ureteral atresia. The treatment concept and outcome are outlined. Antenatal ultrasound had revealed urinary ascites which lead to caesarean section in the 34th gestational week. Persisting anuria was confirmed postnatally and peritoneal dialysis started on the second day of life. Subsequent laparotomy revealed ureteral atresia after 3 cm of patent ureter. We created an ileum conduit after discussing various other therapeutic options. A follow up of 12 months has shown steady function of the stoma with stable renal parameters. An ileal conduit represents a good option if high drainage is necessary in early childhood.
    Journal of pediatric urology 03/2011; 7(5):576-8. · 1.38 Impact Factor
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    ABSTRACT: To evaluate CT-guided radiofrequency (RF) ablation of osteoid osteoma using internally cooled monopolar RF electrodes for technical success, complications and clinical long-term success. Between April 1999 and July 2006, 23 patients were treated under general anesthesia with CT-guided RF ablation using an internally cooled monopolar single RF electrode (Cool-tip, Valleylab, TycoHealthcare, Boulder, USA; active tip: 10 mm). For the removal of the nidus, we used either a manual or an automated drill. The technical success was evaluated by a CT scan (MSCT, Siemens Medical Solutions, Forchheim). The clinical long-term success was investigated by questioning patients prior to discharge, and after 6, 12 and 18 months. After 18 months, patients were interviewed on an annual basis. The technical success rate was 100 %. The nidus was located in n = 19 cases at the lower extremity and in n = 4 cases at the upper extremity. Minor complications were observed for n = 2 patients. The mean hospitalization time was 1.5 d (1-2 d). The mean follow-up was 75.9 months (18-120 months) for n = 23 patients. No local recurrence was observed. One patient had intermediate pain one week after RF ablation without recurrent symptoms. CT-guided RF ablation using an internally cooled monopolar single RF electrode is an effective and safe minimally invasive method for the treatment of osteoid osteoma with excellent clinical long-term success.
    RöFo - Fortschritte auf dem Gebiet der R 01/2011; 183(4):381-7. · 2.76 Impact Factor
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    ABSTRACT: PURPOSE Proton MRI of lung imaging could replace CT as a reference standard in patients with cystic fibrosis by direct visualisation of changes with very low proton density like air trapping, bullae and emphysema. Up to now, it was possible to visualize these changes by MRI merely with polarised gases or perfusion imaging. An improved MRI technique with ultra short echo time opens new possibilities of proton density imaging of the lung. Aim of this study was to compare both modalities, CT and MRI, by using a non modified Helbich-Bhalla-Score. METHOD AND MATERIALS During a period of two years, pulmonary MRI was obtained in 85 patients with cystic fibrosis (range 8-29 years, median15 years). 19 patients of these were scheduled for low dose CT examination because of clinical indication (e.g. acute exacerbation). MRI was performed in a 1.5 T scanner using a GE sequence with ultrashort echo time (TE = 0.8 ms, voxel size 1.6x1.6x15 mm3) in in- and exspiration. Additionally, 3D GE sequences with breathhold and TSE sequences with respiration- and ECG-triggering were performed. At the same day, 40-slice MSCT was carried out adapted to bodyweight (100 or 120 KV, 30-60 mAs, 1 and 3 mm slice thickness, smooth and sharp kernel reconstructions) with additional incremental slices (3 positions) in exspiration. The Helbich-Bhalla-Scores was analyzed by two experienced radiologists in consensus for both modalities without knowledge of the clinical data. To avoid recall bias the time interval between CT and MRI evaluation was four weeks. Correlation, mean difference and accordance in each category of the score were calculated. RESULTS There was a high correlation between both methods (r = 0.87; P < 0,01). The mean score for CT was 12.2 (range 1-18) and for MRI 11.7 (range 2-19) with a mean difference of 0.5 points. Beside a high correlation for findings with long T2* echo time (i.e. infiltrates) we could also state a qualitative accordance of 95-100% in the categories emphysema, bullae and mosaic perfusion (air trapping). CONCLUSION These results suggest that in our patient group scheduled for CT for clinical indications no relevant findings were missed by MR imaging. CLINICAL RELEVANCE/APPLICATION Using ultra short echo time pulmonary MRI offers an excellent radiation free alternative to HRCT by visualization of air trapping, bullae and emphysema without any contrast media.
    Radiological Society of North America 2010 Scientific Assembly and Annual Meeting; 11/2010
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    ABSTRACT: PURPOSE Special MRI technique with ultrashort echo times allows proton density imaging of the lung. This study evaluates the interrelation of lung volume and signal intensity and compares the according lung volumes to the intrathoracic gas volume (ITGV) of body plethysmography. METHOD AND MATERIALS 10 healthy volunteers and 30 patients with cystic fibrosis (CF) (8-21 years, median age 11) were assessed by 1.5 T MRI (Vision Sonata, Siemens) and obtained a pulmonary function test by body plethysmography on the same day. Imaging of lung parenchyma was performed using 2D GRE sequences (TR 2.9 ms, TE 0.8 ms, flip angle 5°) at subterminal in- and exspiration during 2 breathhold periods for each side of the lung. Ventilated pulmonary regions were segmented and analysed to obtain lung volume and histograms of signal intensity (SI) distribution. Relative decrease of lung volume (Vrel) during exspiration was compared to the according increase of relative signal intensity (SIrel) from 0 to 300%. Exspiratory lung volumes were displayed accumulatively and opposed to the associated SIrel. RESULTS The correlation coefficient of signal increase and volume decrease revealed high coherence with r = 0.86 or 0.92 (healthy vs. CF, P < 0.001). Accumulative lung volume showed best correlation with ITGV as a reference standard at SIrel = 225% with r = 0.68 and 0.83 respectively (healthy P = 0.02 vs. CF P < 0.001). Total exspiratory lung volume measured by MRI correlated to ITGV with r = 0.7 and 0.9 (healthy P = 0.02 vs. CF P < 0.001). CONCLUSION Linear correlation between alterations of signal and volume of the lung during exspiration can be detected by MRI. Lung volumes determined by MRI correlate significantly with ITGV as a marker of hyperinflation e.g. in patients with cystic fibrosis. Regional distribution of gas volumes can be assessed by MRI within short examination time. MRI may improve diagnostic accuracy detecting gas distribution disorders that were missed by global lung function tests. CLINICAL RELEVANCE/APPLICATION Improved pulmonary MRI may provide regional quantification of gas distribution disorders within short examination time and reveals lung volumes correlating significantly to body plethysmography.
    Radiological Society of North America 2010 Scientific Assembly and Annual Meeting; 11/2010

Publication Stats

517 Citations
156.56 Total Impact Points

Institutions

  • 2000–2014
    • Universitätsklinikum Tübingen
      • • Policlinic for Orthodontics
      • • Division of Diagnostic and Interventional Radiology
      • • Division of Experimental radiation oncology
      • • Department of Radiology
      Tübingen, Baden-Württemberg, Germany
  • 2001–2011
    • University of Tuebingen
      • • Institute for Neurobiology
      • • Department of Paediatric Surgery
      • • Department of Internal Medicine
      Tübingen, Baden-Württemberg, Germany