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P Rogalla

Publications and source records attributed to P Rogalla.

At least 19 recordsLinked to original sources
PubMed2002

[Multislice CT of the abdomen--current indications and future trends].

Multislice CT systems allow the simultaneous acquisition of multiple slices per gantry rotation. In combination with faster gantry rotation times of 0.5 seconds, the abdominal structures can be displayed in higher spatial and temporal resolution. In MS-CT of the liver it is possible to scan the entire organ with an optimal slice thickness of 2 - 3 mm within a defined perfusion phase in less than 10 seconds. This results in an improved detection and characterization of focal liver lesions. A high-quality, 3-dimensional reconstruction of the hepatic arterial and portalvenous system is obtained with the same data set. The diagnostic use of the simultaneously acquired perfusion data will lead to a better characterization of focal liver lesions in the future. The diagnostics of the pancreas also profits from MS-CT, especially for the detection of small tumors and the evaluation of resectability of a pancreatic carcinoma. All abdominal structures can be displayed in a coronal view without loss of image quality because of the almost isotropic voxels obtained. This proves to be beneficial for the preoperative diagnostics of renal cell carcinomas, especially if the tumor extension into adjacent organs (e. g., liver or spleen) in the longitudinal direction has to be evaluated. The multiplanar display and the sophisticated 3-dimensional reconstruction tools have a substantial value for the abdominal CT angiography. It proves to have a major diagnostic impact on acute abdominal aortic and visceral arterial diseases because even large distances in the z-direction can be covered with high spatial resolution.

Abdominal Neoplasms↗
PubMed2002

[Comparing the visualization of microcalcifications with direct magnification in digital full-field mammography vs. film-screen mammography].

PURPOSE: To evaluate the conspicuity of microcalcifications in magnified mammographic views of preparations obtained with full field digital mammography (FFDM), film-screen mammography (FSM), and the DIMA technique. MATERIAL AND METHODS: Twelve preparations were examined by FFDM and FSM using 1.8 x magnification and DIMA using 7 x magnification. Parameter settings were identical for all three techniques. The number of visible microcalcifications was then determined for each modality by three radiologists. As far as possible, all preparations were X-rayed at 22 kV and 10 mAS. RESULTS: Altogether 9705 calcifications were counted (DIMA: 1609/1542/1534; FFDM: 1020/753/881; FSM: 901/643/822). The total number of microcalcifications identified with the DIMA technique was 4685 as compared to 2654 with FFDM and 2366 with FSM. The calcifications counted with FFDM and FSM thus corresponded to 56.6 % and 50.5 %, respectively, of those identified with DIMA. The differences between the groups were statistically significant (F-Test, p < 0.05). CONCLUSION: Significantly more calcifications are identified when magnified mammographic views of preparations containing microcalcifications are obtained with the DIMA technique compared to FFDM or FSM. FFDM depicts markedly more calcifications than FSM. This means one should increase spatial resolution. Digital mammography offers the potential for improved visualization of microcalcifications with advanced applications.

Breast Neoplasms↗
PubMed2001

Significant correlation between the breakpoints of rare clonal aberrations in benign solid tumors and the assignment of HMGIY retropseudogenes.

Recently, we described a mechanism by which a retropseudogene, during evolution, becomes an exon of a pre-existing active gene. Similar mechanisms may account for the activation of processed genes by chromosomal rearrangements in neoplasms. Because genes of the high-mobility group protein family HMGI(Y) are known to be involved in the development of a variety of benign solid tumors, it was the aim of the present study to analyze breakpoints of clonal chromosome abnormalities in that group of benign tumors for a possible correlation with retropseudogenes of the HMGIY gene. Whereas the HMGIYL1 retrospeudogene has recently been mapped to Xp22.1, we assigned a further retropseudogene by FISH to 4q13, and database research allowed us to assign a third retropseudogene to 12q24.1. Sequence analyses of these retropseudogenes revealed high-identity indices to the HMGIY gene and no frame-shift divergences. Breakpoint information was obtained from cytogenetic aberrations in uterine leiomyomas, lipomas, pleomorphic adenomas, and pulmonary chondroid hamartomas because, in all of these tumor entities, cytogenetic subgroups involving genes of the HMGI(Y) family exist. Chromosomal bands harboring HMGIY retropseudogenes were affected with a significantly higher frequency than expected under the assumption of purely randomly occurring breakages. These results support our hypothesis that HMGIY-related retropseudogenes can be affected by chromosomal rearrangements in benign human tumors.

Base Sequence↗
PubMed2001

Coronary magnetic resonance angiography: experimental evaluation of the new rapid clearance blood pool contrast medium P792.

The signal-enhancing characteristics of a new monodisperse monogadolinated macromolecular MR contrast medium (P792) were evaluated for magnetic resonance angiography (MRA) of the coronary arteries. A total of 15 cardiac examinations were performed in pigs at 1.5 T using a 3D gradient-echo sequence. Images were acquired during breath-hold before and up to 35 min after IV injection of Gd-DTPA (0.3 mmol Gd/kg), Gd-BOPTA (0.2 mmol Gd/kg), and P792 (13 micromol Gd/kg). An increase in the signal-to-noise ratio (SNR) of 97% +/- 17%, 108% +/- 37%, and 109% +/- 31% in coronary arteries and of 82% +/- 19%, 82% +/- 24%, and 28% +/- 18% in myocardium, respectively, was measured during the first postcontrast acquisition. The blood-to-myocardium signal-difference-to-noise ratio (SDNR) was significantly higher for P792 than for the other Gd compounds (P <.05) for up to 15 min after injection. Qualitative assessment showed that visualization of the coronary arteries and their branches was significantly better for P792 compared to the low-molecular Gd compounds (P <.05). The blood pool contrast medium P792 is well suited for MRA of the coronary arteries.

Animals↗
PubMed2001

[Virtual bronchoscopy].

Flexible bronchoscopy represents a clinically well-established invasive diagnostic tool. Virtual bronchoscopies, calculated from thin-slice CT sections, allow astonishing immitations of reality although principal differences exist between both technologies: the fact that colour representation is artificial and concommitant interventions are impossible limits the clinical use of virtual bronchoscopy. However, its value increases when calculations can be attained within minutes due to technological advancements, and when virtually any chest CT is suitable for further postprocessing. Indications, findings and the clinical role of virtual bronchoscopy are discussed.

Bronchoscopy↗
PubMed2001

Large deletion of part of the HMGIC locus accompanying a t(3;12)(q27 approximately q28;q14 approximately q15) in a lipoma.

The high mobility group protein gene HMGIC has been found to be rearranged in a variety of human benign solid tumors. Often, these rearrangements lead to fusion genes of which that between HMGIC and LPP underlying t(3;12)(q27 approximately q28;q14 approximately q15) is by far the most common. Herein, we analysed a lipoma with a t(3;12)(q27 approximately q28;q14 approximately q15). RT-PCR revealed the presence of a HMGIC-LPP fusion transcript composed of exons 1-3 of HMGIC and exons 9-11 of LPP, but the absence of the reverse LPP-HMGIC fusion transcript. Fluorescence in situ hybridization experiments using different probes derived from the HMGIC gene and its 3' vicinity showed the absence of FISH signals on the derivative chromosome 3. Thus, in the present tumor the t(3;12)(q27 approximately q28;q14 approximately q15) was accompanied by a large genomic deletion. Roughly, it can be estimated that at least 170 kb of chromosome 12 material were deleted. To the best of our knowledge, this is the first report showing that the "simple" t(3;12)(q27 approximately q28;q14 approximately q15) results in a large deletion of DNA.

Chromosomes, Human, Pair 12↗
PubMed2001

CT colonography: data acquisition and patient preparation techniques.

The success of a virtual endoscopy is essentially dependent on the image quality of the corresponding 3-dimensional reconstructions. Before loading image data on a post-processing computer, certain prerequisites concerning the source data must be met. To carry out a CT colonography, the source data must be of good quality. High spatial resolution in all geometrical directions, continuous data acquisition without gaps, and artefact-free images are pivotal factors influencing source data. A generally applicable rule is that the size of the smallest detectable polyp is limited by the nominal slice thickness, emphasizing the ultimate importance of the initially chosen primary slice collimation. Furthermore, calculation of an endoluminal view is impossible without sufficient distension of the bowels. Thorough patient preparation that accommodates the technical circumstances for post-processing is also required for attaining a high sensitivity in polyp detection.

Cathartics↗
PubMed2001

[Use of a portable CT scanner for monitoring ventilated patients in an intensive care unit].

PURPOSE: Evaluation of postoperative pulmonary atelectasis using a portable computed tomography (CT) unit. MATERIAL AND METHODS: 5 spiral CT-examinations in low-dose technique were performed on each of 10 patients with partial pulmonary atelectasis after coronary bypass surgery. The patients were artificially ventilated using different levels (0 to +15 cm H2O) of positive end-exspiratory pressure (PEEP). The changes in atelectatic volumes were determined for each side. RESULTS: In 6 patients the primary volume of atelectasis was larger on the left side than on the right. Atelectatic volumes decreased with increasing PEEP. Re-expansion of atelectases was significantly (p < 0.01) better with a PEEP of +15 cm H2O. CONCLUSION: Computed tomography allows visualisation of postoperative atelectasis reliably, even in the low-dose technique. Concordantly, additional therapeutically relevant side findings can be detected compared to conventional chest X-ray. Risky patient transport becomes unnecessary.

Coronary Artery Bypass↗
PubMed2001

[Virtual rendering techniques in otologic imaging].

UNLABELLED: Virtual postprocessing techniques combine the advantages of condensing the large amounts of data provided by high-resolution (HR) cross-sectional imaging modalities with those of three-dimensional (3D) imaging. The techniques and indications for virtual representations in imaging of the middle ear (ME), internal ear (IE), and cerebellopontine angle (CPA) are presented together with practical examples. MATERIAL AND METHODS: HR data sets acquired by computed tomography (CT) and magnetic resonance imaging (MRI) in patients with ME, IE, and CPA pathologies were transferred to a workstation via an internal network to generate endo- or extraluminal 3D views by means of the volume rendering technique (VRT). The source data were acquired using scanners and imaging protocols with the highest resolution available at present: a multislice spiral CT (MSCT) with a slice thickness of 0.5 mm and a reconstruction increment of 0.2 mm and a 3D CISS sequence with a slice thickness of 0.5 mm for MRI. RESULTS: Virtual endoscopy was superior to cross-sectional images for assessing ME pathologies like dysplasia, postoperative changes, and destructive bone processes with extensive soft-tissue involvement; fibrous obliterations of the internal ear and labyrinthine dysplasia were depicted with a superior image quality on 3D renderings compared to conventional reconstruction techniques. Virtual endoscopy of the CPA and external acoustic meatus (EAM) was helpful in detecting and visualizing neurovascular conflicts and in assigning small intrameatal tumors to components of the acousticofacial bundle. A common feature of all applications was that the large numbers of source images could be reduced to a few 3D reconstructions for documentation and optimized communication of the findings between the radiologist and otologist. CONCLUSION: Virtual rendering makes an important contribution towards establishing, presenting, and documenting the findings when certain otologic pathologies have to be assessed. It can be used for routine imaging and allows for more efficient handling of the large amounts of imaging data generated by high-resolution cross-sectional imaging modalities.

Cerebellopontine Angle↗
PubMed2001

A post-processing protocol for three-dimensional visualization of the inner ear using the volume-rendering technique based on a standard magnetic resonance imaging protocol.

A superior diagnostic quality compared to other post-processing (PP) techniques for three-dimensional (3D) inner ear imaging has been attributed to volume rendering (VR). We defined and assessed a VR protocol for 3D visualization of the inner ear in a routine imaging setting. Following definition of a VR protocol by using lower threshold values, surface shading, perspective views and related parameters, standardized 3D views of the inner ear were generated and evaluated in 32 patients suffering from sensorineural or combined hearing loss. Comprehensive inner ear visualization was achieved in 28 patients by means of two 3D shaded-surface views. Incomplete data acquisition (1/32), motion and pulsation artefacts (2/32) and interposed fluid-retaining mastoid cells (1/32) were responsible for non-diagnostic image quality in 4/32 patients. In 5/32 patients modifications of the PP protocol involving the threshold value and depth-cueing parameters helped to establish diagnostic image quality. Mean post-processing time amounted to 5.8 min per site. 3D imaging with the VR technique is suitable for routine inner ear assessment if direct VR, predefined PP protocols and standardized labyrinthine views are used.

Artifacts↗
PubMed2001

High-resolution petrous bone imaging using multi-slice computerized tomography.

Multi-slice computerized tomography (MSCT) is considered to provide superior image quality. We defined a data acquisition protocol for high-resolution (HR) temporal bone imaging using MSCT and assessed its impact on data acquisition and post-processing (PP). The data acquisition protocol was defined in cadaveric phantom studies performed by MSCT and subsequently applied to 38 patients referred for temporal bone assessment. The parameters image quality and diagnostic value of MSCT data were assessed for the cross-sectional source images as well as for 2-dimensional (2D) reformations and 3-dimensional (3D) reconstructions by 3 radiologists by comparison with incremental HR scans of 17 patients with suspected middle ear disorders. The data acquisition protocol yielded HR images with an excellent detail resolution and a comparable image quality of cross-sectional scans and related orthogonal reformations. MSCT achieved higher scores for image quality and diagnostic value (p < 0.001, t-test) than incremental HR CT with regard to both 2D and 3D reconstructions. MSCT improves the image quality of HR cross-sectional scans as well as that of 2D and 3D PP techniques in petrous bone imaging. The radiation exposure of the eye lenses is increased by MSCT as gantry angulation is not yet possible in the helical scan mode.

Algorithms↗
PubMed2001

Assessment of the arteriovenous cerebrovascular system by multi-slice CT. A single-bolus, monophasic protocol.

PURPOSE: We present a protocol for the non-invasive angiographic assessment of the arterial and venous cerebrovascular (CV) system by multi-slice CT. MATERIAL AND METHODS: Data acquisition was performed in a multi-slice CT scanner with a scan range from the carotid bifurcation to the vertex and manual scan start following i.v. administration of 120 ml iodinated contrast medium with a flow rate of 4 ml/s. This protocol was applied in 12 patients with symptoms of acute CV insuffiency. RESULTS: In all patients, comprehensive imaging of the arteriovenous CV system was achieved including the common carotid bifurcation, the third segment of the major cerebral arteries, the dural sinus and the internal cerebral veins. Various CV pathologies, such as a territorial artery occlusion, a thrombotic obstruction of the internal carotid artery, an intracranial arteriovenous malformation and a sinus vein thrombosis, were successfully evaluated. CONCLUSION: Comprehensive assessment of the arteriovenous CV system is possible by the use of a single-bolus, monophasic multi-slice scan technique.

Adult↗
PubMed2001

Dy-EOB-DTPA: tolerance and pharmacokinetics in healthy volunteers and preliminary liver imaging in patients.

RATIONALE AND OBJECTIVES: To investigate the tolerance and pharmacokinetics of the new liver-specific x-ray contrast agent Dy-EOB-DTPA [(4S)-4-(4-ethoxybenzyl)-3,6,9-tris(carboxylatomethyl)-3,6,9-triazaundecanedioic acid, dysprosium (Dy) complex, disodium salt] in healthy volunteers and to obtain preliminary imaging data by abdominal spiral computed tomography (CT) in tumor patients with liver metastases. METHODS: A total of 40 healthy male volunteers received 10-minute intravenous infusions of 0.05, 0.1, 0.25, 0.375, or 0.5 mmol/kg Dy-EOB-DTPA (n = 6 per dose group) or placebo (n = 10). Blood, urine, and feces were sampled for Dy measurements by inductively coupled plasma atomic emission spectrometry (ICP-AES) and for the detection of possible metabolites by high-performance liquid chromatography analysis with ICP-AES detection. Safety parameters were determined before, during, and after the study. Two patients with suspected liver metastases first received 120 mL of iopromide (300 mg iodine/mL; approximately 0.6 mmol/kg) and, 24 or 72 hours later, Dy-EOB-DTPA at a dose of 0.25 mmol/kg. Computed tomography images were obtained 50 seconds after iopromide administration and before and 90 minutes after Dy-EOB-DTPA administration. RESULTS: Dysprosium-EOB-DTPA was well tolerated. At the higher doses (0.375 and 0.5 mmol/kg), there was a slight increase in side effect intensity. In general, nausea, headache, and paresthesia mainly were reported as mild to moderate adverse events. Laboratory parameters did not exceed the normal range. Electrocardiographic, vital sign, or hemodynamic parameters were not affected by contrast agent administration. The terminal half-life of elimination of Dy-EOB-DTPA was approximately 1.5 hours, total clearance was 2 to 3 mL x min(-1) x kg(-1), and the renal clearance was approximately 1.5 mL x min(-1) x kg(-1). There was a significant dose dependence for the following parameters: maximal concentration in blood, terminal half-life, mean residence time, total clearance, urinary excretion, and fecal excretion. The volume of distribution in the steady state and renal clearance were not dependent on dose. In the blood and urine, no metabolites of Dy-EOB-DTPA could be detected. In the tumor patients, CT scanning after Dy-EOB-DTPA injection increased the number of detected metastases from 27 (plain scan) to 40 (iopromide) and then to 41 (Dy-EOB-DTPA) in patient No. 1 and from 1 (plain scan and iopromide) to 3 (Dy-EOB-DTPA) in patient No. 2. CONCLUSIONS: Dysprosium-EOB-DTPA was shown to be a well-tolerated liver-specific contrast agent. Its pharmacokinetic profile is characterized by a terminal half-life of approximately 1.5 hours. There are indications of saturation of liver uptake at the highest dose level of 0.5 mmol/kg. In comparison with plain scans and scans performed after iodinated contrast agent administration, Dy-EOB-DTPA seems to increase the number of detectable liver lesions.

Adult↗
PubMed2001

Virtual endoscopy of the tympanic cavity based on high-resolution multislice computed tomographic data.

OBJECTIVE: This study was designed to assess the value of high-resolution multislice computed tomography (MSCT) data of the petrous bone for the virtual endoscopic visualization of the tympanic cavity. BACKGROUND: The recently introduced MSCT technology has improved spatial resolution in the z axis as well as scan speed in computed tomography. Three-dimensional rendering of high-resolution MSCT data of the petrous bone may be expected to provide endoluminal views of superior image quality, thus competing with transtympanic endoscopy (otoendoscopy). SETTING: This study was conducted at a university teaching hospital. MATERIALS AND METHODS: Cadaveric phantom studies in a MSCT scanner were performed to define a data acquisition protocol, combining adequate detail resolution with low tube current. Subsequently, the cadaveric phantom underwent otoendoscopy. The postprocessing parameters of the three-dimensional rendering protocol were chosen to produce views closely resembling the corresponding otoendoscopic images. High-resolution data from 18 patients with pathologic conditions of the middle ear, as suggested by clinical findings and assessment of cross-sectional data, were postprocessed using the volume rendering technique to generate standardized virtual endoscopic views. A total of 36 virtual endoscopic scans of the tympanic cavity were generated. RESULTS: With regard to intermediate and high-density structures, virtual endoscopic images, based on MSCT data, yielded endoluminal views closely resembling corresponding otoendoscopic views. Virtual endoscopy seems useful for imaging ossicular pathologic conditions such as dysplasia and chain disruption as well as for assessing patient status before and after otosurgery. CONCLUSION: MSCT data sets allow for generating virtual endoscopic views closely resembling otoendoscopic images. The technique is especially useful when ossicular pathologic changes are present as well as for preoperative and postoperative imaging of otologic procedures.

Endoscopy↗
PubMed2000

Point mutations within AT-hook domains of the HMGI homologue HMGIYL1 affect binding to gene promoter but not to four-way junction DNA.

High-mobility group I/Y (HMGI/Y) proteins are chromosomal proteins involved in gene and chromatin regulation. Elevated levels of HMGI/Y proteins were reported in diverse malignant tumors, and rearrangements of their genes are casually involved in the development of benign tumors. In humans, the chromosomal locus Xp22 has been often found to be affected in diverse benign mesenchymal tumors. Recent studies revealed that this region contains a retropseudogene HMGIYL1 which potentially can be activated in a way of "exonization" upon aberrations involving this region. The coding sequence of the HMGIY-L1 is highly homologous to the HMGI(Y) gene. On the protein level, both HMGIYL1 and HMGI differ at few amino acid residues, including their putative DNA-binding domains (DBDs). Here we have approached the question of whether the HMGIYL1 product would be able to adopt a role of HMGI in the context of binding to gene promoters and chromatin. Comparative binding studies, employing protein footprinting technique, revealed that HMGIYL1 has lost the ability to bind to the promoter of the interferon beta gene, but retained its high affinity for the four-way junction DNA. Our results stress the importance of particular residues within the DBDs for DNA binding and demonstrate that tight binding of HMGI/Y proteins to the four-way junction DNA can be achieved in alternative ways. The binding of HMGIYL1 to four-way junction DNA suggests that activation of the HMGIYL1 gene would yield a protein sharing some binding properties with HMG1-box proteins and histone H1. Thus, the HMGIYL1 could interplay together with these components in chromatin regulation.

Active Transport, Cell Nucleus↗
PubMed2000

Distinct organization of DNA complexes of various HMGI/Y family proteins and their modulation upon mitotic phosphorylation.

High mobility group (HMG) proteins HMGI, HMGY, HMGI-C, and Chironomus HMGI are DNA-binding proteins thought to modulate the assembly and the function of transcriptional complexes. Each of these proteins contains three DNA-binding domains (DBD), properties of which appear to be regulated by phosphorylation. High levels of these proteins are characteristic for rapidly dividing cells in embryonic tissues and tumors. On the basis of their occurrence, specific functions for each of these proteins have been postulated. In this study we demonstrate differences in the nature of contacts of these proteins with promoter region of the interferon-beta gene. We show that HMGI and HMGY interact with this DNA via three DBDs, whereas HMGI-C and Chironomus HMGI bind to this DNA using only two domains. Phosphorylation of HMGY protein by Cdc2 kinase leads to impairing of contacts between the N-terminally located DBD and a single promoter element. The perturbations in the architecture of the protein.DNA complexes involve changes in the degree of unbending of the intrinsically bent IFNbeta promoter. Our results provide first insights into the molecular basis of functional specificity of proteins of the HMGI/Y family and their regulation by phosphorylation.

DNA↗
PubMed2000

Schwannoma with angiosarcoma. Report of a case and comparison with other types of nerve tumors with angiosarcoma.

BACKGROUND: Schwannoma with angiosarcomatous change is a rare tumor, the clinical characteristics of which have not been analyzed. METHODS: A patient with schwannoma with angiosarcoma arising in the midneck and clinically mimicking a carotid body paraganglioma is described with a literature review of all previously reported cases and a comparison of their clinical features with those of schwannoma with conventional malignant transformation and cases of neurofibroma and malignant peripheral nerve sheath tumor (MPNST) with angiosarcoma. RESULTS: There are four reported cases, including the present case. Schwannoma with angiosarcoma affects older adults, mainly men. Three tumors arose from the vagus nerve in the neck. Three of the four angiosarcomas were epithelioid in type. Treatment in all cases was surgical resection followed by radiation and chemotherapy in one case and by radiation alone in another. One patient died with residual local angiosarcoma 5 months after the diagnosis. The remaining three patients were alive and disease free at 27 months, 43 months, and 90 months, with distant metastasis (after 15 months) reported only in the patient described in this case report. CONCLUSIONS: Schwannoma with angiosarcoma should be included in the differential diagnosis of presumed carotid body paragangliomas. Like angiosarcoma alone and schwannoma with conventional malignant transformation, but unlike cases of neurofibroma and MPNST with angiosarcoma, the patients are older adults, and there is a male prevalence. Schwannoma with angiosarcoma is capable of local spread with a fatal outcome and of distant metastasis, but follow-up strongly suggests that these patients have a better prognosis than patients with neurofibroma or MPNST with angiosarcoma. Recommended treatment is attempted complete surgical resection followed by radiation therapy and chemotherapy, if it can be tolerated by the patient.

Carotid Body Tumor↗