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Biomedical subjects

G Staatz

Publications and source records attributed to G Staatz.

At least 19 recordsLinked to original sources
PubMed2007

[Ectopic ureter with urinary dribbling in childhood -- a diagnostic challenge: our own experience and review of the literature].

Based on the observations in four girls suffering from constant urinary dribbling we analyzed the special features and difficulties in making the diagnosis of an ectopic ureter. In all patients there was marked diagnostic delay. In one symptomatic case the abnormality was not detected before the age of 18 years. Failure to recognize the characteristic signs and symptoms played a crucial role in delaying the diagnosis. Moreover, imaging of ureteral ectopia represents a diagnostic challenge. The ectopic ureters were associated with dysplastic, poorly functioning renal moieties. Common diagnostic imaging procedures, such as ultrasound, intravenous pyelography, or voiding cystourethrography yielded incomplete diagnostic information and often failed to provide a definitive diagnosis. The latter could only be obtained with MR urography. We assessed the diagnostic value of the different examinations and compared our findings with those reported in the literature.

Adolescent↗
PubMed2006

Evaluation of femoral head vascularization in slipped capital femoral epiphysis before and after cannulated screw fixation with use of contrast-enhanced MRI: initial results.

In this study we used contrast-enhanced magnetic resonance imaging (MRI) to evaluate the vascularization of the femoral head in children with slipped capital femoral epiphysis (SCFE) before and after cannulated screw fixation. Eleven consecutive children with SCFE, seven boys and four girls, aged 10-15 years were included in the study. There were no preslips; four children had acute, three acute-on-chronic, and four chronic SCFE. The MRI examinations were performed in a 1.5 Tesla MR scanner with use of a coronal STIR sequence, a coronal contrast-enhanced T1-weighted spin-echo sequence, and a sagittal three-dimensional gradient-echo sequence. Morphology, signal intensities, and contrast-enhancement of the femoral head were assessed by two radiologists in consensus. Morphologic distortion of the physis, bone marrow edema within the metaphysis and epiphysis, and joint effusion were the preoperative MRI findings of SCFE in each child. In nine children, the vascularization of the femoral head before and after surgery was normal. In one child, a preoperative avascular zone in the superolateral aspect of the epiphysis revascularized completely after surgery. One child with severe SCFE developed avascular necrosis of the femoral head after open reduction of the slip. We conclude that MRI allows for accurate evaluation of the femoral head vascularization before and after surgery in children with SCFE.

Adolescent↗
PubMed2006

[Dose-reduced 16-slice multidetector-row spiral computed tomography in children with bronchoscopically suspected vascular tracheal stenosis -- initial results].

PURPOSE: To evaluate the diagnostic accuracy of contrast-enhanced dose-reduced 16-slice multidetector-row CT (MDCT) in newborns and infants with fiberoptic bronchoscopically suspected vascular-induced tracheal stenosis. MATERIALS AND METHODS: 12 children (4 days to 3 years, 1.2 - 13.5 kg body weight) were examined using i. v. contrast-enhanced 16-slice MDCT (SOMATOM Sensation 16, Forchheim, Germany) without breath-hold and under sedation (11/12). All MDCTs were performed with a dose reduction. The beam collimation was 16 x 0.75 mm, except in the case of one child. MPRs along the tracheal axis in the x-, y- and z-directions and volume-rendering-reconstructions (VRTs) were calculated based on a secondary raw data set in addition to conventional axial slices. 2 radiologists used a three-point grade scale to evaluate the image quality, motion, and contrast media artifacts as well as the usefulness of the 2D- and 3D-reconstructions for determining the diagnosis. Statistical analysis was performed on the basis of a Kappa test. RESULTS: In all cases the cause of the fiberoptic bronchoscopically suspected tracheal stenosis was revealed: compression due to the brachiocephalic trunk (n = 7), double aortic arch (n = 2), lusorian artery (n = 1), vascular compression of the left main bronchus (n = 2). In 3 patients further thoracic anomalies, such as tracheobronchial (n = 2), and vascular (n = 2) and vertebral (n = 1) anomalies were found. The attenuation in the anomalous vessels was 307 +/- 140 HU. The image noise was 9.8 +/- 1.9 HU. The mean dose reduction was 82.7 +/- 3.2 % compared to a standard adult thoracic CT. All examinations were rated as diagnostically good (median 1, range 1, k = 1). 3D images did not show any stair artifacts (median 2, range 1 - 2, k = 1). The image noise was minor to moderate and hardly any motion artifacts were seen (median 1, range 1 - 2, k = 0.8). Contrast media artifacts were rated zero to minor (median 1.5, range 1 - 2, k = 0.676). MPRs (median 1, range 1, k = 1) and VRTs (median 1, range 1, k = 1) were found to be useful for diagnosis. Subsequent vascular surgery was performed on 8 patients. CONCLUSION: Contrast-enhanced dose-reduced 16-slice MDCT is effective for demonstrating the cause of fiberoptic bronchoscopically suspected vascular-induced tracheal stenosis even in very small and severely ill children despite the small contrast media amount and free breathing.

Airway Obstruction↗
PubMed2005

[Diagnostic evaluation of chronic inflammatory intestinal diseases in children and adolescents: MRI with true-FISP as new gold standard?].

PURPOSE: To evaluate the impact of magnetic resonance imaging (MRI) with use of True-FISP sequences in the evaluation of inflammatory bowel-wall changes in children and adolescents with Crohn's disease. Furthermore, the diagnostic procedure in children and adolescents with chronic inflammatory bowel disease (IBD) will be discussed in light of the relevant literature. MATERIAL AND METHODS: Twenty-four children and adolescents aged between 7 and 21 years with suspected or known IBD underwent MRI on a 1.5 T-scanner (Philips ACS-NT, Best, Netherlands). One hour after 1 l of a 2.5 % mannitol solution was given orally, MR imaging was performed using coronal HASTE-M2D, coronal fat-suppressed T2-TSE, axial dynamic T1-weighted GE-sequences before and after i. v.-contrast material injection (0.1 mmol/kg Gd-DTPA) and using a 2D-balanced-FFE-sequence (True-FISP) before and after i. v.-contrast material injection in coronal and axial planes. The MR-images were correlated with endoscopy and the clinical findings. In 14 patients, a recently performed conventional radiographic enteroclysis was available. Each performed MRI sequence was evaluated by three experienced radiologists regarding the sensitivity and specificity of each sequence in the detection of inflammatory bowel wall changes. In addition, the image quality was assessed regarding the different tissue contrasts and the susceptibility to artifacts. The distension of the bowel wall and the patients' acceptance of the MRI examination were recorded. RESULTS: With a sensitivity in detecting inflammatory small bowel changes of 93.3 % (axial pre-contrast, coronal post-contrast) and 100 % (axial post-contrast, coronal pre-contrast), the True-FISP outnumbers the other performed sequences (T1 = 80 %, HASTE = 13.3 % and T2-TSE = 53.3 %). The difference between True-FISP and contrast-enhanced T1 was not statistically significant, whereas the difference between True-FISP and HASTE and T2-TSE, respectively, was statistically significant. The True-FISP sequences revealed a statistically significant superiority regarding the soft-tissue differentiation in comparison to all other performed MR-sequences. The distension of the bowel wall was good in all patients. The patients' acceptance of the MRI examination was excellent. CONCLUSION: The described small bowel MRI examination is appropriate for children and adolescents. With the use of True-FISP sequences, it is a convincing method with an outstanding sensitivity in the diagnosis of IBD. Not least because of the lack of radiation exposure, small bowel MRI ought to replace conventional enteroclysis as a gold standard for IBD diagnosis in children and adolescents.

Adolescent↗
PubMed2005

[High-resolution T1-weighted MR-lymphography of inguinal lymph nodes after interstitial application of Gadomer-17 in animal experiments].

PURPOSE: To evaluate the microstructural anatomy of inguinal lymph nodes in pigs after interstitial MR-lymphography with the dendritic contrast agent Gadomer-17. MATERIAL AND METHODS: High-resolution T1-weighted MR-lymphography was performed in inguinal lymph nodes of 10 domestic pigs (39 - 46 kg) after subcutaneous injection of 10 mumol/kg body weight Gadomer-17 in the hind legs of the animals. A 1.5T MR scanner and a ring-shaped surface coil were used. Two different high-resolution gradient-echo sequences with additionally reconstructed maximum-intensity projections were evaluated in a total of 20 lymph nodes. The high-resolution MR-findings were correlated with the histologic sections of the excised inguinal lymph nodes. RESULTS: Coronal T1-weighted 3D gradient-echo images (TR = 20 msec, TE = 6.1 - 8.3 msec, FA = 20 degrees ) with a slice thickness of 1 mm, a field-of-view of 120 mm and a matrix size of 256 x 256 (reconstructed to 1024 x 1024 voxels) yielding a reconstructed in-plane resolution of 117 x 117 microm (2) were best suited for the high-resolution MR lymphography of inguinal lymph nodes and enabled the differentiation of the hyperintense lymph node sinuses and hypointense lymphoid parenchyma of each lymph node (100 %). Even dilated lymphatic vessels evident in the histologic specimen were best demonstrated on the MIP images. CONCLUSION: High-resolution interstitial MR lymphography with Gadomer-17 allows the visualization of different tissue compartments of inguinal lymph nodes. This new technique is feasible on a routine 1.5T scanner and may offer potential for the detection of micrometastases in lymph nodes of cancer patients.

Animals↗
PubMed2004

[Multislice spiral CT (MSCT) in pediatric radiology: dose reduction for chest and abdomen examinations].

The advent of multislice spiral CT (MSCT) technique has led to new aspects of dose reduction, especially for the dedicated use of MSCT in children. Optimizing pediatric MSCT protocols according to the clinical problem allows reduction of radiation exposure to a minimum without loss of diagnostic quality. The different parameters that influence the degree of dose reduction, like tube current-time product (mAs), tube voltage (kV), collimation and pitch, are discussed in context with previously published data and our own experience in nearly 200 pediatric CT examinations. In our department, the effective mAs is calculated for a pediatric chest MSCT by multiplication of the body weight in kilogram with a factor of 1 to 1.5 and for a pediatric abdominal MSCT by multiplication with a factor of 2 to 2.5. To calculate the equivalent effective dose for a contrast media-enhanced 80 kV protocol, the effective mAs of the 120 kV protocol can be multiplied by 2.7. A factor less than 2.7 means further dose reduction. Compared to the radiation exposure with a standard adult protocol, the effective dose in a pediatric thoracic MSCT could be reduced by up to 92 % in neonates, 89 % in toddlers and 80 % in school children. In abdominal MSCT, the effective dose could be reduced by up to 90 % in neonates, 89 % in toddlers and 83 % in school children. Using an adequate MSCT technique in children by adjusting the CT scanning parameters to the clinical question and body weight of the examined child enables a significant reduction of radiation exposure in comparison to standard MSCT protocols.

Body Weight↗
PubMed2003

[MR-urography and CT-urography: principles, examination techniques, applications].

MR-urography (MRU) and CT-urography (CTU) provide refined imaging of the upper urinary tract not achievable with conventional intravenous urography (IVU). The traditional MR-urographic technique utilizes unenhanced, heavily T2 -weighted turbo spin-echo sequences for obtaining static fluid images of the urinary tract independent of the excretory renal function. T2 -weighted MR-urograms have proved to be excellent in visualizing the dilated urinary tract, even in non-excreting kidneys. In contrast, T1 -weighted MRU reflects the excretory renal function and displays the urine flow through the upper tract after renal excretion of an intravenously administered gadolinium chelate. The gadolinium-enhanced urine is visualized with fast T1 -weighted 3D-gradient-echo sequences. The combination of gadolinium and low-dose furosemide (5 - 10 mg) is the key for achieving a uniform distribution of gadolinium in the collecting system and for avoiding susceptibility artifacts (T2*-effects) in the urine. T1 -weighted excretory MRU provides impressive urograms of both non-dilated and obstructed collecting systems in patients with normal or moderately impaired renal function. Multislice-CT-urography (MS-CTU) is also an excretory urography like T1 -weighted MRU. Furthermore, MS-CTU can be combined with low-dose furosemide for accelerated passage of excreted contrast material obviating the need for abdominal compression. CT-urography is limited by its radiation burden and the nephrotoxicity of radiographic contrast media. Combining MRU or MS-CTU with conventional MRI or CT offers several applications, e.g., diagnosis of intrinsic and extrinsic tumors. Meanwhile, MRU has replaced IVU in pediatric uroradiology and is also recommended for the assessment of renal transplants. MS-CTU may provide valuable information in chronic urolithiasis, especially if associated with a distorted urinary tract anatomy. Both MRU and MS-CTU will play an important role in modern uroradiology.

Adolescent↗
PubMed2003

[Interstitial T1-weighted MR lymph fistulography with Gadomer-17 in an experimental animal model].

PURPOSE: To visualize and localize fistulas of the thoracic duct with interstitial T 1 -weighted MR lymphography using Gadomer-17. MATERIALS AND METHODS: In 10 domestic pigs, leaks of the thoracic duct were created surgically or interventional-radiologically. The lymphatic leakage was located within the abdominal portion of the thoracic duct in 5 pigs, within the thoracic portion of the thoracic duct in 3 pigs, and in both, abdominal and thoracic portions of the thoracic duct, in 2 pigs. Subsequently, 10 micro mol/kg KG Gadomer-17 (1.5-1.8 ml) was administered interstitially in both hind legs of the animals. MR lymphography was performed with a 1.5 T MR unit using two different 3D gradient echo sequences before and 10 - 90 minutes after administration of contrast material. RESULTS: Leaks within the abdominal portion of the thoracic duct were directly visible as opacified fistulas. Indirect signs of active lymphatic fistulas were increasing extravasations of contrast material and free abdominal fluid. The 3D gradient echo sequence with the highest planar resolution (TR = 8,7 - 8,8 ms, TE = 4,2 - 4,3 ms, FA = 40 degrees, matrix size = 327 x 512) was best suited for distinct delineation of the lymphatic system and detailed demonstration of the thoracic duct fistulas. Intrathoracic leaks could not be demonstrated by MR lymphography due to reduced lymphatic flow or extravasated contrast medium at the abdominal puncture site. CONCLUSION: Interstitial MR lymphography with Gadomer-17 allows sensitive detection and localization of abdominally located leaks of the thoracic duct.

Animals↗
PubMed2002

T1-weighted MR-lymphography after intramammary administration of Gadomer-17 in pigs.

PURPOSE: To evaluate the enhancement of regional lymph nodes and lymphatic vessels after intramammary injection of Gadomer-17. MATERIALS AND METHODS: T1-weighted MR-lymphography was performed in 8 domestic pigs after intramammary injection of 5 - 10 micromol/kg bodyweight (bw) Gadomer-17 on a 1.5 T-MR scanner. T1-weighted 3D gradient-echo images were acquired 10 to 120 minutes after contrast material injection in coronal and sagittal planes. The contrast enhancement of the draining lymphatic system was qualitatively assessed by two radiologists applying a three grade scale. RESULTS: T1-Weighted MR-lymphography after intramammary injection of Gadomer-17 was feasible in each pig. A dose of 5 micromol/kg body weight Gadomer-17 was best suited for MR-lymphography of the mammary line and the draining lymphatic system. Enhancement of regional lymph nodes and lymphatic vessels was classified as good in 5, and excellent in three cases. CONCLUSIONS: Intramammary injection of Gadomer-17 allows for good quality T1-weighted MR-lymphography of mammary gland draining regional lymph nodes and lymphatic vessels. This new technique might offer potential for the evaluation of the sentinel lymph node in patients with breast cancer.

Animals↗
PubMed2002

MR signal intensity characteristics in Legg-Calvé-Perthes disease. Value of fat-suppressed (STIR) images and contrast-enhanced T1-weighted images.

PURPOSE: To evaluate the MR signal intensity characteristics in Legg-Calvé-Perthes disease on fat-suppressed (STIR) images and contrast-enhanced T1-weighted spin-echo images, and to develop criteria for the administration of contrast material. MATERIAL AND METHODS: Twenty children with Legg-Calvé-Perthes disease underwent conventional radiography and MR imaging of the hip utilizing fat-suppressed (STIR) sequences and T1-weighted spin-echo sequences before and after i.v. contrast administration. The signal intensity characteristics of the femoral head and the proximal femoral metaphysis were assessed retrospectively by two pediatric radiologists. RESULTS: Evaluation of the MR images revealed six different signal patterns within the femoral head: 1) isointense signal on all images; 2) complete signal void on all images; 3) hyperintense signal on STIR images with; or 4) without contrast enhancement on T1-weighted spin-echo images; 5) isointense signal on STIR images with; or 6) without contrast enhancement on T1-weighted images. Within the metaphysis three different signal patterns were differentiated. CONCLUSION: Combination of fat-suppressed (STIR) sequences and T1-weighted pre- and post-contrast sequences allows an accurate evaluation of Legg-Calvé-Perthes disease. In patients without signal alterations or complete signal loss on fat-suppressed and T1-weighted spin-echo images, administration of i.v. contrast is not necessary. In case of bone marrow edema on fat-supressed images, contrast-enhanced T1-weighted images are required to identify viable osseous fragments.

Adolescent↗
PubMed2002

Treatment of extrahepatic bile duct disease in infancy and early childhood.

Extrahepatic bile duct disease is a rare finding in infancy and early childhood. However, there is an increasing number of patients operated at this age reported in the literature. This increase may have multifactorial reasons, e.g. real increase, better ability of detection as a result of better diagnostic techniques and knowledge of predisposing factors of extrahepatic bile duct disease in childhood, especially in early childhood and infancy. The following report describes three cases of extrahepatic bile duct disease in infancy and early childhood treated at the Department of Surgery of the University of Technology in Aachen, Germany. From 1986 to 1998 28 Patients below 18 years were operated at our Department of Surgery. There was a recognizable increase of patients in 1996, 1997 and 1998. Whereas from 1986 to 1995 an average of 1.5 Cholecystectomies in pediatric patients were done, the years from 1996 to 1998 show an average of 5,33 patients operated per year. Every patient obtained a Cholecystectomy -- 15 conventional open Cholecystectomies and 13 Laparoscopies, which were primarily performed in children in our clinic in 1991. Besides cholecystectomy in one case a Hepaticoenterostomy was necessary and in another case surgical treatment of the Papilla of Vater and the Common Bile Duct was performed. In 22 patients symptomatic Cholelithiasis was the indication for a Cholecystectomy. Another Patient had a gallbladder polyp consisting of heterotopic Duodenal glands, two patients showed a shock gallbladder following trauma and cardiac operation and three patients had chronic Cholecystitis without gallstones. Clinical data was collected and retrospectively reviewed. Additionally, we created a personal questionnaire to carry through a follow-up. Three Patients were less than 3 1/2 years old. The youngest patient was only 5 months old and presented with Cholelithiasis and Choledocholithiasis. Another male patient, aged 2 years received a Cholecystectomy and a Hepaticoenterostomy because of a Choledochal Cyst Type Ib (Todani-Classification). And a 3-year-old-girl had a shock gallbladder caused by thromboembolism following cardiac operation nine days before.

Abdominal Pain↗
PubMed2001

[Value of human recombinant osteogenetic proteins as bone replacement materials in lumbar spondylodesis. Results of an animal experiment study].

Up to now autologous spongiosa may be considered as the golden standard for the filling up of bone defects. Because of the limited quantity, complications at the extraction place and the increasing problems concerning infections when using homologous spongiosa the development of various bone replacement materials was intensified during the last years. The development of various osteogenetic proteins as well as experimental studies using these proteins represent a main point in science at present. It is expected that these substances will lead to a qualitative improvement and increase of bone healing. In the presented study influence of various osteogenetic substances to bone regeneration was examined at 30 breeding sheep after a ventral spine fusion of the segment L4/L5 by a dorsal approach. Bone defect filling was realized at each 10 animals with autologous spongiosa, Bio-Oss as well as the osteogenetic protein 1 (OP-1). To evaluate the progress and outcome of the segmental fusion during a post-operative period of 24 weeks x-ray controls were performed. In the 24th postoperative week after euthanasia of the experimental animals x-ray controls as well as computed and magnetic resonance tomographies were carried out. The results of 26 experimental animals could be analysed. The results were evaluated according to the criterias of an own score-system. Compared with autologous spongiosa OP-1 as a biomaterial for the fusion of spine-sections led to favorable radiologic results because of higher score values concerning the capability of fusion. Our experiences with Bio-Oss demonstrated lower osteogenetic potency after defect filling with this substance. Therefore we cannot recommend Bio-Oss as filling material for the fusion in spine surgery.

Animals↗
PubMed2001

Deep soft-tissue leiomyoma of the popliteal fossa in a 14-year-old girl.

This is the first case report of a deep soft-tissue leiomyoma with intraarticular localization within the knee joint. A 14-year-old girl presented with a painless mass in the dorsal aspect of her knee which she had noticed some 9 months earlier. While on plain radiographs no bony lesions were visible, magnetic resonance imaging (MRI) revealed an intraarticularly located tumor with well-defined margins. Intraoperatively, the tumor was found adjacent to the posterior cruciate ligament. The final diagnosis was established immunohistologically. Although this is a very rare tumor, it has to be considered in the differential diagnosis for soft-tissue swellings of the popliteal fossa.

Adolescent↗
PubMed2001

Magnetic resonance urography in children: evaluation of suspected ureteral ectopia in duplex systems.

PURPOSE: We evaluate the diagnostic accuracy of magnetic resonance urography in children with suspected ectopic ureters and ureteroceles in duplex systems. MATERIALS AND METHODS: A total of 14 children 4 weeks to 8 years old with a total of 18 duplex systems underwent magnetic resonance urography using a 1.5 tesla scanner. After injection of low dose furosemide, half-Fourier rapid acquisition with relaxation enhancement images were obtained for T2-weighted static fluid magnetic resonance urography. Respiratory gated 3-dimensional gradient echo images were acquired for T1-weighted excretory magnetic resonance urography 5 to 30 minutes after intravenously administered gadolinium. RESULTS: All magnetic resonance examinations were successfully performed without sedation. The diagnostic accuracy of T1-weighted excretory magnetic resonance urography depended on the renal function. Twelve duplex systems with a normal excretory function, including 6 bifid ureters and 6 upper moieties with inferomedial ectopic ureters, were analyzed correctly with the exception of a 6 mm. ureterocele in 1 case. In 6 duplex systems with poor or nonfunctioning upper moieties ectopic ureters were only demonstrated on T2-weighted magnetic resonance urograms. CONCLUSIONS: Respiratory gated excretory and static fluid magnetic resonance urography complement each other in the evaluation of duplex systems in children and provide high accuracy in the evaluation of suspected ectopic ureters and ureteroceles.

Child↗
PubMed2001

US-guided nephrostomy with the aid of a magnetic field-based navigation device in the porcine pelvicaliceal system.

PURPOSE: To assess the technique and feasibility of ultrasound (US)-guided nephrostomy performed with the aid of a magnetic field-based navigation device. MATERIALS AND METHODS: Twelve percutaneous nephrostomy procedures were performed in seven domestic pigs under real-time US guidance employing a navigation system. Two magnetic field sensors registered the actual position of the puncture needle and the US transducer. The actual needle position and the aimed puncture tract were graphically projected into the real-time US images, allowing exact navigation of the needle. After placement of the needle into the renal pelvis, the nephrostomy tube was inserted by means of the Seldinger technique. RESULTS: The puncture procedure was successfully performed in each case. The renal pelvis was punctured in a single attempt in 10 of 12 cases. In two cases, multiple attempts were necessary because bending of the puncture needle led to inaccuracies of the navigation system. With exception of two small perirenal urinomas, no complications were seen. CONCLUSIONS: The magnetic field-based navigation device allows easy and accurate performance of nephrostomy guided solely by US.

Animals↗