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Biomedical subjects

M Keberle

Publications and source records attributed to M Keberle.

At least 19 recordsLinked to original sources
PubMed2005

[Value of radiological methods in the diagnosis of biliary diseases].

The modern cross-sectional radiological methods of ultrasound, computed tomography, and magnetic resonance imaging provide manifold possibilities for the diagnosis of inflammatory and tumorous diseases of the gallbladder and the bile ducts as well as stone-related diseases. The invasive methods for direct imaging of the bile ducts, such as endoscopic retrograde cholangiopancreatography, are mainly used within therapeutic concepts. According to the literature, ultrasound and magnetic resonance imaging show a sensitivity of up to 100% in the diagnosis of intra- and extrahepatic cholestasis, but concerning the diagnosis of the cause of cholestasis these methods are limited. Therefore, additional MRI sequences or computed tomography are necessary. Computed tomography is particularly efficient for the diagnosis of the biliary system and adjacent anatomical and pathological structures within the pre- and postoperative period.

Algorithms↗
PubMed2005

[Individualized dose requirement for spiral-CT analysis of the abdomen].

PURPOSE: To search for individualized scan protocols that provide adequate diagnostic information with minimal radiation exposure for abdominal CT in adults. MATERIAL AND METHODS: Beginning with standard settings (120 kVp, 200 mA, 0.75 s, CTDI (w = 11.7 mGy)), which are in the lowest quartile of the actual German radiation dose survey, 119 adults were examined using a single-row detector helical CT with 8 mm collimation and a pitch of 1.5. The individualized scan protocol was defined by repeating the reference scan up to 3 times with different radiation doses following a predefined iteration scheme. The image qualities with standard dose and with individualized dose were assessed independently by 3 radiologists blinded to the exposure parameters. The individualized dose was correlated with the diameter of the patients. RESULTS: The patient diameters varied from 16 to 35 cm and correlated with individualized radiation doses CTDI (w) from 6.4 to 17.6 mGy. We found an exponential correlation (y = 52.3 x e (0.05 x); r(2) = 0.48; p < 0.001) between required tube current (mA) and a. p. diameter (cm) in the epigastric region in adults. CONCLUSION: Maintaining constant exposure parameters results in unnecessary radiation exposure in patients with a diameter of less than 27 cm measured in anterior-posterior direction in the epigastric area. The radiation exposure in adult abdominal CT can be reduced up to 45 % by individualized selection of the tube current without adversely affecting diagnostic performance.

Adult↗
PubMed2004

Functional MR imaging of submandibular herniation of sublingual tissues through a gap of the mylohyoid muscle in two cases of submandibular "masses".

Except for neoplasms, in symptomatic patients with submandibular swellings, gaps of the mylohyoid muscle may be the cause of herniations of sublingual tissues, such as fat and/or the sublingual gland. In two patients with a submandibular swelling, MRI with standard sequences including contrast enhancement was performed to exclude a neoplastic lesion. In addition, we performed a trueFISP sequence during modified Valsalva's maneuver. In both patients, a neoplasm was excluded. Instead, the trueFISP sequence during the modified Valsalva's maneuver showed submandibular herniation of sublingual tissues. If MRI of the floor of the mouth does not show a neoplasm, an additional functional MR investigation should be performed. Gaps of the mylohyoid muscle can be the cause of herniating sublingual tissues (similar to plunging ranulas). During the modified Valsalva's maneuver, sublingual fat and/or gland can herniate and cause a symptomatic submandibular swelling. A coronal trueFISP sequence is particularly suited to demonstrate this.

Adipose Tissue↗
PubMed2003

[Prognostic value of pretreatment CT regarding local control in oropharyngeal cancer after primary surgical resection].

PURPOSE: To evaluate the prognostic implication of tumor infiltration and volume in primarily operated oropharyngeal carcinomas. MATERIAL AND METHODS: In 80 patients with oropharyngeal squamous cell carcinomas (pT 1 = 22, pT 2 = 30, pT 3 = 19 and pT 4 = 9), the tumor volume was measured by pretreatment CT and the extent of tumor infiltration determined by postoperative histologic examination. All patients were followed clinically for local tumor recurrence for at least two years after therapy. The statistical analysis consisted of chi 2 and U tests. RESULTS: The local control rate was 79 % (63/80). Of all evaluated anatomic structures, only midline crossing correlated significantly with local recurrence (p = 0.06). No correlation of tumor volume (p = 0.19) or T stage (p = 0.60) with the local recurrence rate was found. CONCLUSION: After primary surgery, oropharyngeal carcinomas with midline crossing have an increased risk of local recurrence, whereas the tumor volume only has a minor impact on the recurrence rate. This is in contrast to laryngeal or hypopharyngeal carcinomas.

Adult↗
PubMed2003

[Diagnostic impact of multiplanar reformations in multi-slice CT of laryngeal and hypopharyngeal carcinomas].

PURPOSE: Assessment of the diagnostic value of multiplanar reformations (MPR) in multi-slice computed tomography (MSCT) by comparing relevant anatomic structures of the larynx and hypopharynx. MATERIALS AND METHODS: MSCT of the neck was performed in 69 consecutive patients (including 30 laryngeal and 12 hypopharyngeal carcinomas). From a 4 x 1.0 mm collimation data set, 3.0-mm and 1.25-mm axial slices as well as 3-mm coronal and sagittal slices were reconstructed. Using the histological examination as gold standard, sensitivity and specificity regarding tumor infiltration for all relevant anatomical structures of the larynx and the hypopharynx were determined for each reconstruction and compared with the McNemar test. Moreover, 42 patients with laryngeal and/or hypopharyngeal carcinoma were subjectively evaluated to determine whether the respective reconstructions enables a better topographical visualization of the tumor in relation to surrounding structures and, furthermore, whether this has an influence on the therapeutical strategy (operation versus radiation therapy, type of operation, surgical approach). RESULTS: Sensitivities and specificities were not significantly different between the reconstructions. However, coronal and sagittal MPR provided a better topographical visualization of the tumor in 14 of 42 (33 %) of the patients, and influenced the therapeutical strategy in 8 of 42 (19 %) of the patients. A lowered signal-to-noise ratio impeded the evaluation of the relatively thin 1.25-mm axial slices in more than 23 % of the cases. CONCLUSION: Besides the 3-mm axial slices, coronal and sagittal MPR can improve the topographical visualization of laryngopharyngeal tumors and are recommended for preoperative MSCT of laryngeal and/or hypopharyngeal carcinomas. Additionally reconstructed 1.25-mm axial slices can be discarded since they do not hold a higher value compared to 3-mm axial reconstructions.

Adult↗
PubMed2002

Current concepts in imaging of laryngeal and hypopharyngeal cancer.

In adjunct to direct laryngoscopy, CT and/or MRI are needed for an accurate staging of laryngeal and hypopharyngeal carcinomas because both cross-sectional imaging modalities are known to reliably evaluate deep tumor infiltration. Except for the clinical background, this article reviews technical aspects of CT and MRI, the pathologic appearance of laryngeal and hypopharyngeal carcinomas, and therapeutically relevant diagnostic aspects.

Adult↗
PubMed2002

High resolution ultrasound detects a decrease in pannus vascularisation of small finger joints in patients with rheumatoid arthritis receiving treatment with soluble tumour necrosis factor alpha receptor (etanercept).

OBJECTIVE: High resolution ultrasound (HRUS) was used to investigate the effects of tumour necrosis factor alpha (TNFalpha) blockade on pannus formation and vascularisation of small finger joints in patients with active rheumatoid arthritis (RA). METHODS: Five patients with active RA were treated with etanercept, a soluble TNFalpha receptor protein, for one month. Before, during, and after treatment the patients were followed up by clinical rheumatological examination, determination of their subjective pain score, blood chemistry, and by HRUS of the second metacarpophalangeal (MCP) joint of the right hand. RESULTS: One month after treatment with etanercept, rheumatological examination showed a significant decrease in a modified single joint rheumatic disease activity index (from 2.9 (SD 0.2) to 1.2 (0.7); p<0.05) in all patients. Moreover, a significant decrease in the general pain score (from 4.7 (0.4) to 1.8 (0.6); p<0.05) and in C reactive protein (CRP) levels was seen (from 3.02 (0.9) to 0.24 (0.1); p<0.05). Concordantly, HRUS showed a significant reduction in pannus vascularisation of the MCPII joints (from 23,602 (5339) to 2907 (1609) colour signals/region of interest, CS/ROI; p<0.001). Pearson's correlation coefficient between the results obtained by HRUS and the clinical response was 0.85. CONCLUSION: HRUS is promising as an additional useful method in the assessment of RA activity, and probably also in monitoring therapeutic responses.

Aged↗
PubMed2001

Spiral CT of the neck: When do neck malignancies delineate best during contrast enhancement?

The aim of this study was to determine the time of best contrast of neck malignancies in contrast-enhanced CT. The CT was done in 20 patients with squamous cell carcinoma using a standard protocol (100 ml contrast agent at 2 ml/s). Dynamic series of the tumors were performed (scan interval 6 s). In all relevant structures of the neck, densities were measured to obtain time-density curves. The best tumor contrast was measured > or =50 s after the start of the injection, and the best contrast of lymph nodes < or =75 s. For staging and volume measurements of neck primaries the best achievable contrast is necessary. Using the examined single-bolus technique, spiral CT allows a combination of perfect tumor contrast with a good contrast between lymph nodes and neck vessels between 50 and 75 s after starting the injection.

Aged↗
PubMed2001

[Comparison of 3D power doppler ultrasound, color doppler ultrasound and digital subtraction angiography in carotid stenosis].

PURPOSE: To compare easy-to-perform three-dimensional power Doppler ultrasound (3D PDUS) to color Doppler ultrasound (CDUS) and digital subtraction angiography (DSA) in the assessment of internal carotid artery (ICA) stenoses in patients with severe atherosclerosis. METHODS: 26 ICA's (7 without stenosis, 4 low-, 4 middle-, and 11 high-grade stenoses) in 13 patients were examined with DSA, CDUS, and 3D PDUS. CDUS and 3D PDUS were performed with a 7.5 MHz standard transducer and a Sonoline Elegra ultrasound machine. The three methods were performed and interpreted by different persons who were not aware of the diagnoses. RESULTS: Regarding the degree of stenosis correlations between DSA and 3D PDUS were r = 0.98 (p < 0.001), between DSA and CDUS r = 0.97 (p < 0.001), and between CDUS and 3D PDUS r = 0.95 (p < 0.001). Sensitivity and specificity regarding the detection of a high-degree stenosis was 90% and 100% for 3D PDUS, and 100% and 93.3% for CDUS. CONCLUSION: Even in cases with severe atherosclerosis, both sonographic methods reveal similar results comparable to DSA. 3D PDUS does not result in a diagnostic improvement on CDUS, however, it does give the new opportunity for complete data storage, reconstruction, and survey presentations.

Aged↗
PubMed2001

Clinical trial on the accuracy of a freehand and sensor-independent three-dimensional power Doppler ultrasound system measuring diameters, volumes and vascularity of malignant primaries of the neck.

AIM: Diameters, volumes and vascularity of malignant primaries of the neck are of substantial importance for staging and prognosis. The purpose of this study was to determine the accuracy of a newly developed freehand and sensor-independent three-dimensional power Doppler ultrasound system (3D PDUS) in the assessment of these parameters. METHOD: 24 patients with squamous cell carcinomas of the neck underwent conventional ultrasound in B- and power Doppler-mode (US), 3D PDUS, and computed tomography (CT). Diameters (sagittal, longitudinal, and transverse) and volumes of the tumours were correlated with hand-segmentated CT images, whereas tumour vascularity was compared with US. RESULTS: 3D PDUS and CT correlated highly regarding diameters and volumes (correlation coefficients r = 0.98/P < 0.001 and r = 0.98/P < 0.001, respectively). 3D PDUS and US correlated highly regarding vascularity (r = 0.92/P < 0.001). CONCLUSION: Although 3D PDUS is based on a freehand and sensorless data acquisition, it appears to be as accurate as CT or US for measurements of diameters, volumes and vascularity of neck malignancies. In spite of the excellent results it has to be mentioned that this technique needs a lot of training and its general use has to be employed with caution.

Adult↗
PubMed2001

[Interobserver variability in CT of oro- and hypopharyngeal carcinomas].

PURPOSE: To evaluate the inter- and intraobserver reproducibilities of computed tomography (CT) in patients with oro- and hypopharyngeal carcinomas. METHODS: Two independent readers interpreted the CT images of 41 patients with hypopharyngeal carcinomas, 45 patients with oropharyngeal carcinomas, and 23 patients without a tumor. All relevant subregional anatomic structures were evaluated for the presence of tumor infiltration. Statistical analysis was done by using Cohen's kappa and the Wilcoxon test; subregional prevalences, sensitivities, and specificities were also determined. RESULTS: Mostly, especially for clinically relevant subregions, moderate and substantial inter- and intraobserver reproducibilities were determined (range of the determined kappa values: 0.25-1.00). The kappa values of the intraobserver reproducibilities of both readers were not significantly different (P = 0.20). The kappa values of the intraobserver reproducibilities were in almost all the cases higher than the respective kappa values of the interobserver reproducibility. CONCLUSION: CT of oro- and hypopharyngeal carcinomas can be interpreted with clinically acceptable variability. A higher agreement can be achieved if repeated interpretation is done by a single person.

Adult↗
PubMed2001

[Comparison of iodinated and barium-containing contrast media of different viscosity in the detection of pharyngeal perforation].

PURPOSE: In contrast to esophageal perforations, the more radiopaque barium-suspensions are not as important as iodinated aqueous contrast agents for the detection of pharyngeal perforations. This study was performed to find out whether the highly different viscosities (of iodinated and barium-containing contrast agents with comparable radiopacities) are a reason for this. METHODS: Viscosity, subjective difference in contrast, and CT-density of an iodinated aqueous (Telebrix) and a 50 wt/vol% barium-containing contrast agent (Micropaque) were determined. Moreover, to exclude postoperative perforation, 104 patients were prospectively examined by pharyngography using both contrast media. Pharyngographies of patients with perforation were later compared by two independent readers. All patients with perforation were followed up clinically to exclude complications due to barium administration. RESULTS: In-vitro comparison showed comparable radiopacity but the 50 wt/vol% barium-suspension was much more viscous than the iodinated contrast agent. During pharyngography, totally, 14 perforations were clearly delineated with the iodinated aqueous contrast agent. However, two of them were not detected with the barium-suspension. All the other perforations presented equally. CONCLUSIONS: Given a sufficient radiopacity, a low viscosity appears to be essential for a contrast agent to detect especially pharyngeal perforations. Thus, we recommend the sole use of an iodinated contrast agent (at suspicion of aspiration as isoosmolar variant) for this purpose.

Adult↗
PubMed2001

Comparison of axial reconstructed ultrasonographic images from three-dimensional data volumes and computed tomographic scans in the documentation and detection of liver lesions.

OBJECTIVE: To compare axial reconstructed ultrasonographic images from three-dimensional data volumes and conventional computed tomographic scans in documentation and detection of liver lesions. METHODS: The livers of 23 patients were examined by a multifrequency curved array transducer to acquire three-dimensional data volumes and by conventional computed tomography The ultrasonographic device was equipped with three-dimensional ultrasonographic technology allowing for real-time parallel movement in every plane within an acquired data volume. Axial ultrasonographic images reconstructed from three-dimensional data volumes were compared with conventional computed tomographic scans. RESULTS: When both methods were taken together, a total of 51 different liver lesions could be detected. Reconstructed ultrasonographic images depicted 44 (86%) of 51 lesions, and computed tomographic scans showed 46 (90%) of 51 lesions. Compared with computed tomography, ultrasonography depicted 5 additional lesions in 3 of the patients (4 hemagiomas and 1 unspecified lesion), whereas 7 lesions were missed in another 4 patients (4 metastases, 2 calcifications, and 1 cyst). The Pearson correlation coefficient between ultrasonography and computed tomography was r = 0.84 (P < .001). CONCLUSIONS: Our study shows that ultrasonographic images can be effectively reconstructed from three-dimensional data volumes. With respect to documentation and detection of liver lesions, the results obtained by three-dimensional ultrasonography appear comparable with those obtained by conventional computed tomography. However, several technical and procedural limitations have to be respected.

Adult↗
PubMed2000

[Reninoma: a rare cause of hypertension. Case report, review of the literature and possibility for organ preserving operation].

A 20-year-old man with no past medical history and no clinical symptoms was referred for examination because of severe hypertension. The blood chemistry studies showed elevated levels of peripheral renin with evidence of secondary aldosteronism. Sonography and computed tomography demonstrated a mass of the left kidney. After excluding all other possible causes for severe hypertension, excision of the tumor was performed. Histological studies confirmed the diagnosis of a juxtaglomerular cell tumor. Reninoma represents a rare but surgically curable cause of hypertension. The clinical suspicion of this tumor is very important because of the young age of the patients. If the diagnosis is confirmed a renal sparing surgery should be the treatment of choice.

Adenocarcinoma↗
PubMed2000

Computed tomography after lymphangiography in the diagnosis of intestinal lymphangiectasia with protein-losing enteropathy in Noonan's syndrome.

Noonan's syndrome is a rare congenital disorder that may be associated with abnormalities in the lymphatic drainage. In this case of a 21-year-old man CT after bipedal lymphangiography confirmed the diagnosis of intestinal lymphangiectasy causing protein-losing enteropathy in Noonan's syndrome by showing contrast-enhanced abnormal lymphatic vessels in the mesentery and the intestinal wall. Because of the benefit of diet in case of intestinal involvement, we recommend a thorough documentation of the lymphatic drainage with lymphangiography followed by CT, if clinical signs of lymphatic dysplasia, such as pleural effusions, lymphedema, or hypoproteinemia are present.

Adult↗