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R Röttgen

Publications and source records attributed to R Röttgen.

At least 19 recordsLinked to original sources
PubMed2008

[Diagnostic value of multislice perfusion CT in dementia patients].

BACKGROUND: The diagnostic value of perfusion CT in dementia patients was retrospectively evaluated in comparison to the Mini-Mental State Examination (MMSE). MATERIAL AND METHODS: The perfusion CT database of 55 subjects was investigated. All patients underwent an unenhanced, contrast-enhanced, and perfusion CT of the head. The clinical evaluation of the degree of dementia was performed with the MMSE. In the perfusion CT data, 24 ROI were marked. Then blood volume (BV), blood flow (BF), and mean transit time (MTT) were calculated and compared with the ipsilateral and contralateral regions and with the degree of dementia. RESULTS: With increasing degree of dementia, a significant decrease of the occipital and temporal BV was found. A significant decrease of the BF in the frontal lobe, basal ganglia, and occipital region was found. Concurrently, the MTT increased significantly in the basal ganglia region. The group with Alzheimer's disease showed significant regional hypoperfusion compared with the group of cognitively normal subjects in the frontal, basal ganglia, occipital, and temporal region. CONCLUSIONS: The cerebral perfusion decreased with increasing degree of dementia. The inexpensive and widely available perfusion CT reveals information about regional differences of cerebral perfusion, which may be useful in differentiating severity and types of dementia.

Aged↗
PubMed2006

Magnetic resonance imaging in the assessment of cystic pancreatic lesions: differentiation of benign and malignant lesion status.

PURPOSE: To characterize cystic pancreatic lesions and tumors with magnetic resonance imaging (MRI), and to assess the value of morphological criteria in differentiating pseudocysts versus cystic tumors and benign versus malignant cystic tumors. MATERIAL AND METHODS: Twenty-three patients with cystic pancreatic tumors or lesions underwent plain and contrast-material-enhanced MRI, including magnetic resonance cholangiopancreatography (MRCP). The MR findings were characterized and analyzed by two readers, and the role of various imaging criteria and combinations thereof for final lesion assignment were assessed. Final diagnoses were obtained from the results of open surgery (n = 19) and/or biopsy (n = 4). RESULTS: Final diagnoses included cystic tumors (n = 11) and pseudocysts (n = 12). The lesions were located in the head (56%) and body or tail (44%). Lesion diameters ranged from 7 to 50 mm. Various lesion contrast enhancement patterns were observed for both benign and malignant lesions. Serous cystadenomas were located in the head, they were lobulated, and had wall diameters < or = 2 mm; with the combination of these characteristics all patients with serous cystadenoma could be identified, whereas in no other patient was this constellation observed. CONCLUSION: MRI facilitated the diagnosis of serous cystadenomas, although no definite morphologic criterion for the differentiation between pseudocysts and mucinous cystadenomas was identified. In consideration of the substantial therapeutic consequences, either diagnostics in unclear cystic pancreatic lesions should comprise cyst fluid analysis if necessary, or eligible patients should be referred for surgical resection.

Adult↗
PubMed2005

[Detection of airways stenoses: comparison of virtual and flexible bronchoscopy].

PURPOSE: To compare virtual with flexible bronchoscopy for the detection of bronchial stenoses. MATERIALS AND METHODS: In a retrospective study, we compared the results of 26 patients, who had clinical suspected pathologies of the tracheobronchial airways and underwent both flexible bronchoscopy and multislice CT with 3D surface rendering of the airways. Flexible bronchoscopy and virtual bronchoscopy were compared as to the rate of detecting bronchial stenoses. For statistical analysis, we divided the tracheobronchial tree in the following sections: trachea, 2 main bronchi, 6 lobar bronchi, 18 segmental bronchi and 36 subsegmental bronchi, corresponding to 63 bronchial sections for each patient (on average) and a total of 1638 bronchial sections for all 26 patients. We graded the bronchial stenosis as less than 50 %, as 50 to 95 % and as complete obstruction. RESULTS: Virtual bronchoscopy detected 25 bronchial stenoses, while flexible bronchoscopy only revealed 17 stenoses. Stenoses with a diameter less than 50 % were found with virtual bronchoscopy 14 times and with flexible bronchoscopy 10 times. Stenoses with a diameter between 50 and 95 % were detected 7 and 4 times, respectively, and complete obstructions 4 and 3 times, respectively. Tracheobronchial stenoses were well recognized with virtual bronchoscopy. Moreover, the virtual method enabled the visualization of high-grade stenoses and post-stenotic areas that could not be passed by the fiberoptic bronchoscope. Virtual bronchoscopy detected stenoses at a higher rate but the difference was not statistically significant (stenoses < 50 %: p = 0.352, 50 - 95 %: p = 0.339, complete obstruction: p = 0.696). CONCLUSION: Virtual bronchoscopy is a useful non-invasive method for the diagnostic evaluation of the tracheobronchial tree. In comparison with flexible bronchoscopy, virtual bronchoscopy is superior in revealing high-grade stenoses and visualizing post-stenotic areas.

Adult↗
PubMed2005

[The effect of the field strength on standardized MRI of the brain to demonstrate cranial nerves and vessels: a comparison of 1.5 and 3.0 Tesla].

PURPOSE: Comparison of MR images acquired as routine examinations at a field strength of 3.0 T and 1.5 T to determine whether and to which degree the image quality improves at the higher field strength of 3.0 T. MATERIALS AND METHODS: Routine MR images of 200 patients were examined retrospectively, with 100 images obtained at 1.5 T and 100 obtained at 3.0 T. The examinations were performed with a quadrature head coil and focused on the basal cisterns because of the abundance of small distinct structures in this region. We selected the T2-weighted 2D-FSE sequence in transverse direction for comparison. At both field strengths, the same section thickness of 5 mm and a matrix of 512 x 388 (FOV: 220 mm) were used. The quality of the images was evaluated with regard to depicting the cranial nerves N. III, V - X, the AICA and PICA. For comparison, image quality was rated with a score from 1 (well defined) to 5 (not depicted). RESULTS: A score of 1 was obtained in 46 % of the anatomic structures examined at 3.0 T and in only 9.2 % at 1.5 T. A score of 2 was given in 27.6 % of the anatomic structures at 3.0 T vs. 23.5 % at 1.5 T, a score of 3 in 17.2 % vs. 28.1 %, a score of 4 in 8.6 % vs. 28.7 %, and a score of 5 in 0.4 % vs. 10.3 %, respectively. The Mann-Whitney U test showed significance at p < 0.001 for the comparison of images at 1.5 and 3.0 Tesla. CONCLUSION: Routine magnetic resonance imaging using the same quadrature coil technique and similar acquisition times at 3.0 T and 1.5 T shows an improvement for T2-weighted images at the higher field strength.

Adolescent↗
PubMed2005

[Computed tomographic criteria as expected effect to inhaled nitric oxide in patients with severe acute respiratory distress syndrome].

PURPOSE: Inhaled nitric oxide (iNO) is an effective therapy for severe hypoxemia in most patients with acute respiratory distress syndrome (ARDS). For unknown reason, a subset of ARDS patients does not respond favorably to iNO therapy. We hypothesized that radiological manifestation of lung injury may be related to iNO response. MATERIALS AND METHODS: We retrospectively analyzed data from n = 25 ARDS patients who received iNO, and underwent chest CT within 72 h prior to inhaled treatment. The morphology of coherently pathologic lung tissue was characterized by the length of the borderline between consolidated, infiltrated and atelectatic lung tissue and radiologically normal lung tissue. This quantity was expressed as relative fraction of the visceral pleural circumference and averaged over all CT slices. Furthermore we semiquantitatively determined the total volume of consolidated lung tissue as part of the whole lung. RESULTS: In n = 6 non-responders to iNO (DeltaPaO2 < 10 %), we determined a short relative borderline between normal and consolidated lung tissue due to the presence of large and coherently consolidated lung regions. In n = 19 iNO responders (DeltaPaO2 > 10 %), we found significantly less coherently consolidated lung tissue evidenced by an increased relative borderline when compared to iNO non-responders (0.09 +/- 0.02 vs. 0.1 +/- 0.01; P < 0.05). Moreover, there was a moderate and significant correlation between DeltaPaO2 induced by iNO and the relative borderline in all patients studied (R = 0.59; P < 0.05). Total fraction of consolidated lung tissue volume was not different between iNO non-responders and responders (60 +/- 3 % vs. 54 +/- 2 % n. s.). CONCLUSION: Our data demonstrate that the gross morphological distribution of pathological lung tissue influences iNO response in ARDS. Inhaled NO was most beneficial in injured lungs characterized by many small consolidated areas surrounded by normal lung tissue. The increased borderline between pathologic and normal lung tissue offers additional possibility for iNO to divert blood flow from shunt areas to ventilated lung regions, which consequently improves arterial oxygenation.

Adult↗
PubMed2005

[Combination of dynamic MR enteroclysis (Sellink) and MR colonography to diagnose Crohn's disease].

PURPOSE: To investigate whether a combined examination with MRI enteroclysis and MRI colonography is practicable and would provide additional findings in the regions seen with ileo-colonoscopy in the work-up of patients with Crohn's disease. MATERIAL AND METHODS: Twenty-five consecutive patients with Crohn's disease (CD) (age range 19 to 42 years, mean age 29.2 years, gender ratio male:female 8:17) were retrospectively studied. All patients underwent conventional ileo-colonoscopy as a standard of reference followed by a combined examination of MRI enteroclysis and MRI colonography at 1.5T within 15 days. Two blinded radiologists evaluated the MRI examinations and compared them with the colonoscopic results. RESULTS: The MRI examination detected 31 inflamed bowel segments in 25 patients. In comparison to colonoscopy, 5 additional, endoscopically inaccessible lesions were found by MRI and only 2 lesions were missed by MRI. Compared to colonoscopy, MRI found 7 of 10 fistulas detected by colonoscopy, and 3 otherwise indiscernible abscesses. The detection of inflamed bowel segments by means of MRI (endoscopy) revealed a sensitivity of 88.8 % (100 %), specificity of 80 % (100 %) and an overall accuracy of 96 % (100 %). CONCLUSION: This study provides strong evidence that the combination of MRI enteroclysis and MRI colonography is practicable and supplies additional results regarding the regions which are not seen with ileo-colonoscopy in the work-up of patients with Crohn's disease.

Adult↗
PubMed2005

Magnetic resonance cholangiopancreatography: image quality, ductal morphology, and value of additional T2- and T1-weighted sequences for the assessment of suspected pancreatic cancer.

PURPOSE: To assess image quality and duct morphology on magnetic resonance cholangiopancreatography (MRCP) and also the value of additional T2- and T1-weighted sequences for differentiation of benignity and malignancy in patients with suspected pancreatic tumors. MATERIAL AND METHODS: One-hundred-and-fourteen patients received MRCP and unenhanced and contrast material-enhanced MR imaging. MR results were analyzed independently by two blinded readers, and subsequently correlated with the results from surgery, biopsy, and follow-up. Assessment included the evaluation of image quality, duct visualization and morphology, and the differentiation of pancreatic lesion status (benign versus malignant). RESULTS: Overall, 49 patients had benign final diagnoses, while 65 had a malignant diagnosis. Image quality of single-shot thick-slab MRCP was rated significantly better than the MIP images of multisection MRCP. With MRCP alone, the two readers' accuracy in the assessment of pancreatic lesion status was 72% (95% CI, 64% to 83%) and 69% (95% CI, 56% to 77%), respectively; with the addition of T2- and T1-weighted images the accuracy significantly improved to 89% (95% CI, 82% to 95%) and 84% (95% CI, 77% to 92%) for readers 1 and 2, respectively. CONCLUSION: Single-shot thick-slab MRCP and multisection MRCP provide complementary results; however, single-shot MRCP had superior image quality. Moreover, assessment of ductal morphology with MRCP alone facilitated the diagnosis of different pathologic conditions of the pancreatobiliary system in the majority of patients. However, with the addition of T2- and T1-weighted sequences the overall diagnostic accuracy was significantly improved and thus we consider that a comprehensive MR approach should comprise both MRCP techniques and parenchymal sequences.

Adult↗
PubMed2005

Colon dissection: a new three-dimensional reconstruction tool for computed tomography colonography.

PURPOSE: To improve the sensitivity of computed tomography (CT) colonography in the detection of polyps by comparing the 3D reconstruction tool "colon dissection" and endoluminal view (virtual colonoscopy) with axial 2D reconstructions. MATERIAL AND METHODS: Forty-eight patients (22 M, 26 F, mean age 57 +/- 21) were studied after intra-anal air insufflation in the supine and prone positions using a 16-slice helical CT (16 x 0.625 mm, pitch 1.7; detector rotation time 0.5 s; 160 mAs und 120 kV) and conventional colonoscopy. Two radiologists blinded to the results of the conventional colonoscopy analyzed the 3D reconstruction in virtual-endoscopy mode, in colon-dissection mode, and axial 2D slices. RESULTS: Conventional colonoscopy revealed a total of 35 polyps in 15 patients; 33 polyps were disclosed by CT methods. Sensitivity and specificity for detecting colon polyps were 94% and 94%, respectively, when using the "colon dissection", 89% and 94% when using "virtual endoscopy", and 62% and 100% when using axial 2D reconstruction. Sensitivity in relation to the diameter of colon polyps with "colon dissection", "virtual colonoscopy", and axial 2D-slices was: polyps with a diameter >5.0 mm, 100%, 100%, and 71%, respectively; polyps with a diameter of between 3 and 4.9 mm, 92%, 85%, and 46%; and polyps with a diameter < 3 mm, 89%, 78%, and 56%. The difference between "virtual endoscopy" and "colon dissection" in diagnosing polyps up to 4.9 mm in diameter was statistically significant. CONCLUSION: 3D reconstruction software "colon dissection" improves sensitivity of CT colonography compared with the endoluminal view.

Colon↗
PubMed2005

Magnetic resonance imaging including magnetic resonance cholangiopancreatography for tumor localization and therapy planning in malignant hilar obstructions.

PURPOSE: To assess image quality and overall accuracy of magnetic resonance imaging (MRI), including two magnetic cholangiopancreatography (MRCP) techniques, for the diagnostics and preoperative work-up of malignant hilar obstructions. MATERIAL AND METHODS: Thirty-one patients with malignant hilar obstructions (hilar cholangiocarcinoma, n=30; hepatocellular carcinoma, n=1) received MRCP by two techniques (single-shot thick-slab and multisection thin-slice MRCP) and unenhanced and contrast material-enhanced MRI. MR assessment included the evaluation of image quality and visualization of bile ducts (5-point scale), and the classification of tumor status. MR results were subsequently correlated with the results from surgery and pathology. RESULTS: The maximum intensity projections of multisection thin-slice MRCP had significantly more artifacts compared to MRCP in the single-shot thick-slab technique, and overall image quality of single-shot thick-slab MRCP was rated significantly superior compared to multisection thin-slice MRCP (4.4 +/- 0.7 and 4.1 +/- 0.9, respectively). Moreover, ductal visualization of different parts of the biliary system was rated superior with single-shot thick-slab MRCP. In contrast, the original data from multisection thin slice MRCP facilitated visualization of periductal lesions and adjacent structures. Overall MR accuracy for the assessment of tumor status, periductal infiltration, and lymph node metastases was 90%, 87%, and 66%, respectively. CONCLUSION: For evaluation of malignant hilar obstructions, MRCP by the single-shot thick-slab technique had superior image quality and fewer artifacts; in contrast, besides sole biliary visualization, multisection MRCP depicted complementary adjacent parenchymal and periductal structures. We therefore recommend MRI, with a combination of both MRCP techniques, for the diagnostic work-up and therapy planning of malignant hilar obstructions.

Adult↗
PubMed2004

[Short-term CT findings after osteosynthesis of fractures of the vertebral spine].

PURPOSE: Evaluation of a correlation between surgical stabilization of fractures of the vertebral spine and postoperative short-term CT findings with special attention to degenerative changes. MATERIALS AND METHODS: The pre- and post-operative CT of 55 patients (43male, 12 female, age: 7 - 73 years, mean = 37.7 years) with traumatic fractures of the vertebral spine who underwent surgical stabilization using an internal fixator were analyzed retrospectively. The interval between surgical intervention and first postoperative CT control did not exceed one week. The interval to the second short-term follow-up CT ranged from 6 up to 24 months (mean: 10.3 +/- 2.7 months). The consensus reading of the short-term CT by two experienced radiologists was compared to the pre- and immediately postoperative CT examinations and with the neurologic findings. Statistical analysis was done using the chi-square- or the Fisher's exact-test. RESULTS: No statistically significant correlation (p > 0.05) was found between the patient's age and the postoperative incidence of osteoporosis, spondylarthrosis, scoliosis, spondylolisthesis or disc protrusion after posttraumatic surgical stabilization using an internal fixator. Also, there was no significant correlation between the fracture's type or location, presence of polytraumatization, the technique of surgical intervention, and the incidence of postoperative degenerative changes in the neighboring segments. The thesis has not been verified (p > 0.05) that polysegment stabilization or prior surgical interventions at the vertebral spine with scar induction are responsible for a higher rate of degeneration. The only risk factor observed for postoperative scoliosis was the burst rotation fracture type C1.3 (AO-classification). CONCLUSIONS: No short-term acceleration of degenerative changes after surgical intervention in vertebral spine fractures was observed. However, due to the short-term interval between surgical intervention and follow-up CT (mean: 10.3 +/- 2.7 months), a final conclusion cannot yet be drawn. A follow-up CT seems to be indicated in patients with increasing complaints during this period. Thus, low grade complications can be diagnosed early.

Adolescent↗
PubMed2004

[The diagnostic value of radial multiplanar reformatting (MPR) in the CT-diagnosis of pulmonary embolism].

PURPOSE: To evaluate the diagnostic value of radial reformatting of axial multislice CT (MS-CT) data sets in the presumptive diagnosis of pulmonary embolism. MATERIALS AND METHODS: In 126 cases with the presumptive diagnosis of an acute pulmonary embolism, 4- and 8-slice axial MS-CT data sets were radially reformatted. The pulmonary vessels were evaluated by five experienced radiologists who determined the number of thrombi at the level of the segmental and subsegmental arteries. A pulmonary artery was considered as thrombosed if it showed at least one unambiguous filling defect on two consecutive sections. It was determined whether the artery was uniformly opacified without filling defects, contained thrombotic material or was completely occluded by a blood clot. Pulmonary vessels that could not be evaluated because of moving artifacts or inadequate opacification were classified as negative. Finally, all experts gave a subjective estimate concerning the simplicity of the diagnosis for both reconstructions. RESULTS: The diagnosis of thromboembolism at a subsegmental level was significantly different for axial sections and radial reconstruction: at 4-slice CT, 77 subsegmental thromboembolisms were found in axial sections vs. 98.6 in radial reconstructions; at 8-slice CT, 23.6 in axial sections vs. 31.2 in radial reconstructions; and using the combined evaluation, 103.2 in axial sections vs. 130.6 in radial reconstructions, with a significance of p = 0.043. The five judges did not find any significant differences in the number of the blood clots in each pulmonary segment. Concerning the simplicity of the diagnosis, the subjective judgment classified the radial reconstructions as better in 49.7 % and the axial sections as better in 22 %. The radial reconstructions of the 4-slice CT were classified as better in 45.7 % vs. 25 % and the 8-slice CT as better in 66 % vs. 16 %. CONCLUSION: Using radial multiplanar reformatting of the MS-CT data sets improves significantly the recognition of subsegmental pulmonary embolism.

Acute Disease↗
PubMed2004

Computed tomography-guided pulmonary nodule localization before thoracoscopic resection.

PURPOSE: To assess the success rate and complication rate of a CT-guided pulmonary nodule-marker system before thoracoscopic resection. MATERIAL AND METHODS: In 24 patients (15 M, 9 F; age range, 18-71 years) a total of 25 pulmonary nodules (in 1 patient 2 lesions simultaneously) were marked with a special wire under CT-guidance and then thoracoscopically resected. We evaluated lesion size, lesion distance to the pleura, the time of intervention, complications, and thoracoscopic success rate. RESULTS: Mean lesion size was 7 mm (range 4-15 mm) and mean lesional distance to the pleura was 13 mm (range 2-31 mm). The pulmonary nodule-marker system was positioned successfully in all 25 pulmonary nodules within 5-11 min (mean 7.5 min). Minimal pneumothoraces were observed in five patients with no requirements of chest drains. In addition, no bleeding complications or hematothorax were observed. All 25 pulmonary nodules could be resected thoracoscopically. However, in one patient (4%), the guide-wire dislocated during thoracoscopy, but the lesion could be successfully resected during thoracoscopy. CONCLUSION: The CT-guided placement of the pulmonary nodule-marker system used here offers a safe and accurate guide for the localization of small pulmonary nodules during thoracoscopic resection.

Adolescent↗
PubMed2003

[Accuracy of routine MRI in lesions of the supraspinatus tendon--comparison with surgical findings].

PURPOSE: To determine the correlation of the extent of lesions of the supraspinatus tendon in MRI's of the shoulder with surgical or arthroscopic findings using the classification of Snyders and Batemann, respectively. MATERIALS AND METHODS: The preoperative MRI's of 80 patients (age: 16 - 76/47.4 +/- 14.0 years) which were performed due to various complaints of the shoulder were analyzed retrospectively by two experienced and blinded radiologists. We evaluated the incidence and the extent of partial or complete ruptures of the supraspinatus tendon. After MRI, an arthroscopic or open surgical intervention was performed (= gold standard). Various MR-scanners were used with a field strength of 1.0 T (17 cases), or 1.5 T (63 cases) and flexible or inflexible arthro coils. Additionally to plain MRI, 38 of 80 patients underwent contrast enhanced MRI. The MR and the surgical or arthroscopic findings were compared and statistically analyzed. RESULTS: Neglecting the localization and the extent of discontinuity of the supraspinatus tendon, the sensitivity of the 80 MRI's was 0.93, the specificity 0.69, and the accuracy 0.85. The sensitivity increased to 0.96 with constant specificity and an accuracy of 0.83 excluding the lesions with an extent below 1 cm. Compared with non-enhanced examinations, the contrast enhanced MRI revealed higher sensitivity (+ 7 %, 0.89 vs. 0.96), higher specificity (+ 11 %, 0.64 vs. 0.75), and higher accuracy (+ 8 %, 0.81 vs. 0.89) in depicting lesions of the supraspinatus tendon at all. On T 1 -weighted images, the detection of lesions at all and the differentiation between partial and complete ruptures were improved significantly by contrast enhancement, especially in lesions with an extent below 1 cm. Diagnostic failures were seen in examinations without intravenous contrast application, artifacts, extent of the lesion below 1 cm, differentiating between degeneration and partial rupture of the tendon, differentiating between severely degenerated tendons with partial rupture and complete rupture, and covered ruptures. CONCLUSIONS: The performance and consecutively the analysis of the widely used MRI of the shoulder is often not sufficiently reliable in its present routine form. To be able to compete with other imaging modalities such as sonography, standardized MR protocol, contrast enhancement as needed, avoiding the described source of failure, and an exact analysis should be applied.

Adolescent↗
PubMed2003

[Evaluation of left ventricular volumes in patients with congenital heart disease and abnormal left ventricular geometry. Comparison of MRI and transthoracic 3-dimensional echocardiography].

PURPOSE: To assess the new method of 3-dimensional echocardiography in comparison to the "gold standard" MRI as to its ability to calculate left ventricular volumes in patients with congenital heart disease. MATERIALS AND METHODS: Eighteen patients between the ages of 3.9 to 37.3 years (mean: 12.8 +/- 9.7) with a geometrically abnormal left ventricle were examined using a 1.5T scanner with a fast gradient-echo sequence (TR = 14 ms, TE = 2.6 - 2.9 ms, FOV = 300 - 400 mm, flip angle = 20 degrees, matrix = 128 : 256, slice thickness = 5 mm, retrospective gating) in multislice-multiphase technique. Transthoracic 3D-echocardiography was performed with a 3.5 MHz transducer and a Tomtec (Munich, Germany) system for 3D reconstruction. RESULTS: Volume calculation was possible in all patients with 3D-echocardiography, but the muscle mass calculation only succeeded in 11 of 18 patients (61 %) due to inadequate visualization of the entire myocardium. Comparing MRI and 3D-echocardiography, the correlation was r = 0.97 for the end-systolic volumes, r = 0.98 for the end-diastolic volumes, r = 0.79 for the end-systolic muscle mass and r = 0.77 for the end-diastolic muscle mass. The agreement between both methods was considered good for the calculated end-diastolic volumes and sufficient for the calculated end-systolic volumes. The muscle mass calculations showed larger differences especially for the end-systolic mass. Mean intraobserver variability was 18.6 % for end-systolic and 8.3 % for end-diastolic volumes. CONCLUSION: In patients with an abnormal left ventricular configuration due to congenital heart disease, the new method of 3D-echocardiography is sufficient for volume calculations in preselected patients. The high intraobserver variability is still a limitation of transthoracic 3D-echocardiography in comparison to MRI.

Adolescent↗
PubMed2003

[CT-colonography with the 16-slice CT for the diagnostic evaluation of colorectal neoplasms and inflammatory colon diseases].

PURPOSE: Comparison of the performance of virtual and conventional colonoscopy for the detection of colorectal polyps and inflammatory colon diseases using a 16-slice spiral CT scanner. Furthermore, presentation of the first experiences with a new three-dimensional reconstruction mode ("colon-dissection") that dissects the colonic wall like a pathologic-anatomic preparation to increase the sensitivity. MATERIALS AND METHODS: Forty patients were studied using a 16-slice spiral CT (Lightspeed 16, General Electric Medical Systems, Milwaukee, Wisconsin 53201, USA). The examination was performed after standard oral preparation for colonoscopy. The colonic distension was achieved with room air and intravenous butylscopolamine. Images were obtained in supine and prone position using a detector configuration of 16 x 0.625 mm, pitch 1.7, rotation time 0.5 s, 160 mAs and 120 kV. Axial reconstruction with a slice thickness of 0.625 mm. The CT data were assessed by two radiologists on an Advantage Workstation (Volume Analysis 2, USA) using a software with the capabilities of axial, multiplanar and volume rendering, virtual endoscopy, and colon dissection. Conventional colonoscopy was used to determine the sensitivity. RESULTS: A total of 30 polyps were found in 8 patients and a carcinoma was detected in two patients. Colonography identified 4 polyps with a diameter of 10 mm or more, 6 polyps with a diameter of 5 mm to 9.9 mm, 11 polyps with a diameter of 3 to 4.9 mm and 9 polyps with a diameter of 3.0 mm or less. There were two false negative findings (one polyp of 3 mm and one of 4 mm had been overseen) and two false positive findings for polyps (polyps of 4 mm and 6 mm). The sensitivity and specificity for the detection of colonic polyps were 93% and 94% with the "colonic-dissection" mode, 87 % and 94 % with the "virtual-endoscopy" mode and 63 % and 97 % with multi-planar reconstruction, respectively. Depending on the diameter of the colonic polyps, the "colon-dissection" mode ("virtual-coloscopy") had a sensitivity and specificity of 100 % and 100 % for polyps with a diameter over 5.0 mm, 91 % and 82 % for polyps with a diameter from 3.0 to 4.9 mm and 89 % and 78 % for polyps with a diameter under 3.0 mm, respectively. Inflammatory colon diseases presented as thickening of the colon wall over 5 mm. CONCLUSIONS: Virtual colonoscopy with 16-slice spiral CT allows accurate detection of colonic polyps, including small polyps below a diameter of 3 mm. In comparison with the 2D- and 3D-"virtual-endoscopic" reconstruction, the 3D-reconstruction software "colon-dissection" achieves the highest sensitivity for the detection of colonic masses. Therefore, the combination of a 16-slice spiral CT and the "colon-dissection" reconstruction software provides a high resolution in the z-axis for detecting colonic masses and polyps down to a diameter of less than 2 mm, with a sensitivity of about 90 %. This sensitivity is much higher than the sensitivity achievable with 4-slice spiral CT and without "colon-dissection" mode. A thickened colon wall over 5 mm indicates inflammatory colon disease.

Colonic Polyps↗
PubMed2003

[Diagnostic value of three-dimensional reconstruction in CT of traumatic spinal fractures].

PURPOSE: Evaluation of the diagnostic value of three-dimensional CT-reconstruction in the pre-operative evaluation of traumatic fractures of the spine, compared with axial slices and two-dimensional reconstruction. MATERIALS AND METHODS: The CT image data of 65 patients with 85 different acute traumatic spine fractures (C 2 through L 5) were collected in a period of 42 months. Retrospectively performed 2D- and 3D-reconstructions were analyzed independently by three CT-experienced readers using the Magerl classification and the readings compared with intraoperative findings or the final diagnoses. RESULTS: The fractures were classified according to the AO-classification as 56 compression, 16 distraction and 13 rotation fractures. Axial slices alone incorrectly classified 2 (1.2 %) of 168 (56 fractures x 3 readers) type A fractures. The CT classification was incorrect in 17 (35.4 %) of 48 (16 fractures x 3 readers) type B fractures and in 31 (79.5 %) of 39 (13 fractures x 3 readers) type C fractures. The 2D-reconstruction increased the percentage of incorrect diagnoses to 13 (7.7 %) type A, to 26 (54.2 %) type B and to 27 (69.2 %) type C fractures. The 3D-mode incorrectly classified 2 of 168 type A fractures (1.2 %), 6 of 48 type B fractures (12.5 %), and 1 of 39 type C fractures (2.6 %). The axial mode was superior to the 2D-reconstructions in type A and type B fractures, but inferior in type C fractures. The percentage of correctly classified type B fractures was significantly higher (p < 0.05) with 3D-reconstruction than with the 2D-mode. In type C fractures, this percentage was significantly higher (p < 0.001) with the 3D-mode than with axial slices or 2D-reconstruction. The interactive monitor analysis of the 3D-reconstructions with additional virtual cutting by the reader improved the analysis, especially the evaluation of the spinal canal. CONCLUSION: The 3D-reconstruction in traumatic spine fractures significantly improves the diagnostic outcome, especially the visualization and classification of rotation fractures. Its disadvantages are a slight increase in artifacts and impaired visualization of small details. Interactive monitor analysis and post-processing of the 3D-mode proved to be advantageous.

Adult↗
PubMed2003

Placement of transjugular intrahepatic portosystemic shunt via the left hepatic vein under sonographic guidance in a patient with right hemihepatectomy.

In a patient with refractory ascites after right hemihepatectomy TIPS was created between the left hepatic vein and the left portal vein via a transjugular approach. The puncture was guided only by sonography from the epigastrium. Portosystemic pressure gradient was reduced from 28 to 7 mm Hg and ascites disappeared. This case shows that TIPS can be created with technical and clinical success after right hemihepatectomy as left hepatic vein to left portal vein shunt under sonographic guidance.

Hepatectomy↗