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  • 1
    Electronic Resource
    Electronic Resource
    Histological heterogeneity of neuroradiologically suspected adult low grade gliomas detected by Xenon enhanced computerized tomography (CT) (1996)
    Springer
    Acta neurochirurgica 138 (1996), S. 1341-1347 
    Details
    ISSN: 0942-0940
    Keywords: Low grade gliomas ; Xenon CT ; stereotactic biopsy ; histological grading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Xenon-enhanced computerized tomography (XeCT) was performed on 14 consecutive adult patients presenting with seizures showing supratentorial non-enhancing radiologically uniform appearing low grade gliomas on CT/MR images. Pre-operative XeCT patterns were compared with postoperative histological diagnosis, grading and Ki67 proliferation indices (PI). After gross-total, subtotal resection or biopsy, 11 astrocytomas, 2 oligodendrogliomas and 1 oligo-astrocytoma were diagnosed and graded: Grade I: 2 patients (Ki67-PI=0.5–0.8), Grade I–II: 4 patients (Ki67-PI=0.3–1.5), Grade II: 3 patients (Ki67-PI=0.5–3.5), Grade II–III: 4 patients (Ki67-PI=3.8–6.8) and Grade III: 1 patient (Ki67-PI=5.2), (Kernohan Classification). Xenon CT studies revealed different flow patterns, correlating with the postoperative histological diagnosis, grading and proliferation indices: A tumour group with well defined, delayed, only minimally enhancing tumour area (5 patients, Grade I, I–II or II), a second group with less well defined low-flow-area borders and inhomogenous, strong enhancement within the tumour (4 patients, Grade II–III, III) and a third group with fast enhancing tumours was identified. The third pattern was exclusively shown in the 2 oligodendrogliomas (Grade I and II–III) and 1 oligo-astrocytoma (Grade II). The preliminary report identifies the Xenon enhanced CT as a beneficial pre-operative investigation for patients with radiologically uniform appearing suspected adult supratentorial low-grade gliomas, which may give information about the presence of anaplastic foci or oligodendroglial components.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01411065
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  • 2
    Electronic Resource
    Electronic Resource
    Tracheal intubation and cervical spine excursion: direct laryngoscopy vs. intubating laryngeal mask (2001)
    Oxford, UK : Blackwell Science Ltd
    Anaesthesia 56 (2001), S. 0 
    Details
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Until recently, the most appropriate technique of intubating a patient with a cervical spine injury has been the subject of debate. Tracheal intubation by means of the intubating laryngeal mask (Fastrach™), a modified conventional laryngeal mask airway, seems to require less neck manipulation. The aim of this study was to compare the excursion of the upper cervical spine during tracheal intubation using direct laryngoscopy with that during intubation via the laryngeal mask (Fastrach™), by examination of lateral cervical spine radiographs in healthy young patients. The intubating laryngeal mask (Fastrach™) caused less extension (at C1−2 and C2−3) than intubation by direct laryngoscopy. Direct laryngoscopy is still the fastest method to secure an airway provided no intubating difficulties are present. However, in trauma patients requiring rapid sequence induction and in whom cervical spine movement is limited or undesirable, the intubating laryngeal mask (Fastrach™) is a safe and fast method by which to secure the airway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2044.2001.01869.x
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  • 3
    Electronic Resource
    Electronic Resource
    Stable xenon CT in patients with chronic cerebrovascular disease (1996)
    Springer
    Neuroradiology 38 (1996), S. S47 
    Details
    ISSN: 1432-1920
    Keywords: Cerebrovascular disease ; Functional imaging ; Cerebral blood flow ; Xenon-enhanced computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Xenon-enhanced CT (XeCT) is a method of measuring regional cerebral blood flow (rCBF). Although it is used for acute and perioperative assessment the ability of XeCT to show hypoperfused areas in vivo, as compared with morphological imaging modalities other than noncontrast CT, is not defined. Correlation with MRI helps to define the smallest detectable hypoperfused area. We examined 17 patients 6 weeks after acute cerebral infarcts with CT, XeCT and MRI and the findings were compared. All examinations were performed with the same slice angulation and thickness and the sizes of the abnormal areas were measured. XeCT showed a high correlation with MRI, but less so with conventional CT Lesions appeared significantly smaller on CT than on XeCT or MRI. No significant difference between MRI and XeCT changes was found. The minimal lesion on MRI correlating with a hypoperfused area on XeCT was 0.8 cm2, whereas lesions measuring less than 0.5 cm2 on MRI could not be detected on XeCT. The good correlation between XeCT and MRI underlines the reliability of rCBF examinations with XeCT A significant difference between CT and XeCT findings shows the difficulty of interpreting hypoperfused regions only by correlation with CT. Combined XeCT and MRI gives a better estimate of the vascular state of the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02278118
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  • 4
    Electronic Resource
    Electronic Resource
    Tumour blood flow and partition coefficients: correlation with grade of cerebral gliomas using xenon-enhanced computed tomography (1997)
    Springer
    Neuroradiology 39 (1997), S. 627-632 
    Details
    ISSN: 1432-1920
    Keywords: Key words Xenon CT ; Astrocytoma ; Brain-blood partition coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It is possible to underestimate the grade of nonenhancing cerebral tumours on conventional contrast-enhanced MRI or CT. Differentiation of high- and low-grade gliomas by measurement of the brain-blood partition coefficient lambda (Tλ ) with Xe-enhanced CT (XeCT) has been reported. We assessed the practical applications of XeCT in suspected low-grade astrocytomas. We examined 15 patients with tumours which showed no contrast enhancement on conventional MRI and CT, using XeCT. Tumour blood flow (TBF) and Tλ were calculated. Fourteen patients underwent surgery, one patient had a biopsy. We recognised three histological groups. While Tλ differed significantly between them, TBF did not. Group 1 contained grade II–III astrocytomas and Tλ was 0.77; group 2 contained grade I–II astrocytomas with Tλ 1.14, and group 3 four oligodendrogliomas in which a Tλ of 1.50 was found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002340050481
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  • 5
    Electronic Resource
    Electronic Resource
    Stable xenon CT in patients with chronic cerebrovascular disease (1996)
    Springer
    Neuroradiology 38 (1996), S. S47 
    Details
    ISSN: 1432-1920
    Keywords: Key words Cerebrovascular disease ; Functional imaging ; Cerebral blood flow ; Xenon-enhanced computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Xenon-enhanced CT (XeCT) is a method of measuring regional cerebral blood flow (rCBF). Although it is used for acute and perioperative assessment the ability of XeCT to show hypoperfused areas in vivo, as compared with morphological imaging modalities other than noncontrast CT, is not defined. Correlation with MRI helps to define the smallest detectable hypoperfused area. We examined 17 patients 6 weeks after acute cerebral infarcts with CT, XeCT and MRI and the findings were compared. All examinations were performed with the same slice angulation and thickness and the sizes of the abnormal areas were measured. XeCT showed a high correlation with MRI, but less so with conventional CT. Lesions appeared significantly smaller on CT than on XeCT or MRI. No significant difference between MRI and XeCT changes was found. The minimal lesion on MRI correlating with a hypoperfused area on XeCT was 0.8 cm2, whereas lesions measuring less than 0.5 cm2 on MRI could not be detected on XeCT. The good correlation between XeCT and MRI underlines the reliability of rCBF examinations with XeCT. A significant difference between CT and XeCT findings shows the difficulty of interpreting hypoperfused regions only by correlation with CT. Combined XeCT and MRI gives a better estimate of the vascular state of the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002340050917
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  • 6
    Electronic Resource
    Electronic Resource
    CT und MRT von Dünndarminterponaten nach oropharyngealen Tumorresektionen (1996)
    Springer
    Der Radiologe 36 (1996), S. 217-220 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter MRT ; CT ; Jejunum transplantat ; Plattenepithelkarzinome ; Key words MRI ; CT ; Jejunal patch ; Squamouse cell carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Freely transplanted, microvascularly anastomosed jejunal patches can be used to cover soft tissue defects in the oral cavity or oropharynx after the resection of malignant tumors. Even a patch without complications or alteration from tumor recurrence is morphologically diverse. Therefore it is difficult to distinguish between malignant and benign alterations, and knowledge of the possible morphological spectrum and the significance of an alteration is of practical interest. Computed tomography (CT; n = 30) and magnetic resonance imaging (MRI; n = 13) were used for follow-up examinations in patients who had an operative reconstruction with a jejunal patch. Three parts of a patch were differentiated with both imaging modalities: the region of the anastomosis, the mesenterial fatty tissue and the intestinal wall. The morphology of the patches correlated with clinical findings in the following cases. The patches were identified satisfactorily by CT and MRI. The appearance of patches without complications was influenced by a variable degree of fibrosis and by persistent intestinal folds. Recurrent tumors only infiltrated the margins of the patches. Destructive alterations in the patches were always less severe than those in the original orofacial soft tissue. Postoperative follow-up examinations with CT and MRI are particularly important when tumor recurrences spread under a patch, since these tumors are invisible in the clinical examinations. CT was advantageous in demonstrating osseous alterations and showed less loss of image quality in patients for whom the implantation of multiple metallic hardware during the operation had been necessary.
    Notes: Zusammenfassung Zur Deckung von Weichteildefekten nach Tumorresektionen im Bereich der Mundhöhle und im Oropharynx können freie Transplantate verwendet werden. Eine häufig angewandte Technik ist der Einsatz frei transplantierter, mikrovaskulär anastomosierter Dünndarmlappen. Bereits das komplikationslose Transplantat weist eine erhebliche morphologische Vielfalt auf. Eine Abgrenzung gutartiger von bösartigen Veränderungen kann deshalb schwierig sein, weshalb die Kenntnis des Spektrums an morphologischen Alterationen von praktischem Interesse ist. Mittels Computertomographie (CT) (n = 30) und Magnetresonanztomographie (MRT) (n = 13) wurden im Rahmen der postoperativen Tumornachsorge Patienten mit Dünndarminterponaten untersucht. An den Interponaten wurden folgende Anteile unterschieden: die Anastomosenregion, das Mesenterium und die Darmwand. Die Morphologie dieser Anteile wurde mit dem klinischen Befund korreliert. Die Ergebnisse zeigen eine zufriedenstellende Abgrenzbarkeit der einzelnen Anteile der Transplantate mit beiden tomographischen Methoden. Die morphologische Heterogenität der als komplikationslos eingestuften Transplantate zeigte sich v. a. in einer unterschiedlichen Ausprägung postoperativer Veränderungen, wie Fibrosierung oder der Persistenz des intestinalen Faltenreliefs. Lokale Tumorrezidive infiltrieren die Interponate hauptsächlich in den Randpartien und destruieren das intestinale Gewebe in weit geringerem Ausmaß als die ortseigenen oralen oder pharyngealen Weichteile. Die Wichtigkeit der radiologischen Untersuchung wird durch Rezidivtumore, welche unterhalb des Dünndarminterponats wachsen und dadurch dem klinischen Nachweis entgehen können, unterstrichen. In der Tumornachsorge können sowohl die MRT als auch die CT eingesetzt werden, wobei aufgrund der besseren Nachweisbarkeit ossärer Läsionen sowie der geringeren Artefaktauswirkung metallischer Implantate der CT derzeit eher der Vorzug zu geben ist.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050063
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  • 7
    Electronic Resource
    Electronic Resource
    Die Magnetresonanztomographie in der Dentalradiologie (Dental-MRT) (1999)
    Springer
    Der Radiologe 39 (1999), S. 1044-1050 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter MRT ; Dental CT ; Dentalradiologie ; Pulpitis ; Dentogene Zysten ; Key words MRT ; Dental CT ; Dental radiology ; Pulpitis ; Dentigerous cysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose: To demonstrate the usefulness of Dental-MRT for imaging of anatomic and pathologic conditions of the mandible and maxilla. Methods: Seven healthy volunteers, 5 patients with pulpitis, 9 patients with dentigerous cysts, 5 patients after tooth transplantation and 12 patients with atrophic mandibles were evaluated. Studies of the jaws using axial T1- and T2-weighted gradient echo and spin echo sequences in 2D and 3D technique have been to performed. The acquired images were reconstructed with a standard dental software package on a workstation as panoramic and cross sectional views of the mandible or maxilla. Results: The entire maxilla and mandibula, teeth, dental pulp and the content of the mandibular canal were well depicted. Patients with innflammatory disease of the pulp chamber demonstrate bone marrow edema in the periapical region. Dentigerous cysts and their relation to the surrounding structures are clearly shown. After contrast media application marked enhancement of the dental pulp can be found. Conclusion: Dental-MRT provides a valuable tool for visualization and detection of dental diseases.
    Notes: Zusammenfassung Ziel dieses Beitrags ist die Vorstellung der Untersuchungsmöglichkeiten des Ober- und Unterkiefers mittels Magnetresonanztomographie (Dental-MRT) und ihre Anwendung bei der Diagnose zahnmedizinischer Erkrankungen. Sieben gesunde Probanden, 5 Patienten mit Pulpitis, 9 Patienten mit dentogenen Zysten, 5 Patienten nach Zahntransplantationen und 12 Patienten mit atrophem Unterkiefer wurden untersucht. Axiale T1- und T2-gewichtete Gradientenecho- und Spinecho-Sequenzen in 2D und 3D-Technik wurden durchgeführt. Nach der Untersuchung wurden zusätzliche Panoramaschnitte und orhoradiale Rekonstruktionen des Ober- und Unterkiefers, unter Verwendung einer gebräuchlichen Dental-Software, angefertigt. Der gesamte Ober- oder Unterkiefer, Zähne, Pulpa und der Inhalt des Mandibularkanals können gut dargestellt werden. Patienten mit einer Entzündung der Zahnwurzel können ein deutliches Knochenmarksödem in der Periapikalregion zeigen. Bei Patienten mit odontogenen Zysten ist die Beziehungen zu den umgebenden Kieferstrukturen gut darstellbar. Nach Kontrastmittelgabe zeigt sich ein Enhancement in der Zahnpulpa. Die Dental-MRT ist ein nützliches Verfahren zur anatomischen Darstellung des Kieferbereichs und zahnmedizinischer Erkrankungen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050600
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  • 8
    Electronic Resource
    Electronic Resource
    Indikationen und Embolie-Monitoring bei lumeneröffnenden Therapien der A. carotis (2000)
    Springer
    Der Radiologe 40 (2000), S. 792-797 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Karotisendarterektomie ; Stentgeschützte Angioplastie der A. carotis ; Transkranielle Doppler-Sonographie ; Keywords Carotid endarterectomy ; Angioplasty and stenting ; Transcranial doppler sonography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Carotid endarterectomy (CEA) is proven to be beneficial in symptomatic patients with high-grade carotid stenosis (70% to 99%; residual lumen as a percentage of the normal distal internal carotid artery) on condition that the peri-operative risk for mortality and morbidity is less than 6%. A minority of the “leading experts” in North America (48%) and Western Europe (28%) recommends carotid endarterectomy in asymptomatic patients in general. Most experts suggest to perform surgery only in asymptomatic patients who are at risk for carotid occlusion in the near future or embolism. At its present state, angioplasty and stenting is an experimental although promising technique which will have to be compared to carotid endarterectomy. Criteria for duplex grading of internal carotid stenosis have been established and systematically validated to results of angiography. Pre-surgical use of angiography will more and more be restricted to selected patients in whom the results of duplex sonography remain inconclusive. The detection of microemboli with transcranial doppler sonography seems to be of particular importance before and during carotid angioplasty and stenting.
    Notes: Zusammenfassung Die Kriterien für eine gesicherte Indikation zur Operation einer symptomatischen Karotisstenose ergeben sich auf der Basis randomisierter Studien: Gefordert wird ein klinisches Ereignis passend zur Annahme einer (Thrombo)embolie aus der Karotisstenose innerhalb der letzten 6 Monate, ein Stenosegrad größer 70% (bezogen auf die distale A. carotis interna) und ein perioperatives Risiko für Tod oder Schlaganfall kleiner 6%. Eine allgemeine Empfehlung zur Operation einer asymptomatischen Karotisstenose kann auf der Basis der vorliegenden Studien nicht gegeben werden. Eine asymptomatische Karotisstenose begründet nur in Einzelfällen die Indikation zu einer operativen Behandlung. Die stentgeschützte Angioplastie (Stent-PTA) ist zum gegenwärtigen Zeitpunkt ein experimentelles Verfahren, das nur im Rahmen von Studienprotokollen unter Einbeziehung einer Ethikkommission zur Anwendung kommen sollte. In randomisierten Studien wird derzeit untersucht, ob die Karotisendarterektomie und Stent-PTA bei Patienten mit symptomatischen Carotisstenosen hinsichtlich des perioperativen Risiskos und der Langzeitergebnisse gleichwertig sind. Das Embolie-Monitoring mittels transkranieller Doppler-Sonographie scheint vor und während der Durchführung der Stent-PTA von Bedeutung zu sein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050825
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  • 9
    Electronic Resource
    Electronic Resource
    Xenon-CT und Perfusionskernspintomographie in der Diagnostik von Gliomen des Gehirns (1998)
    Springer
    Der Radiologe 38 (1998), S. 930-934 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Zerebrale Gliome ; Xenon CT ; Perfusions MRI ; Astrozytome ; Regionaler zerebraler Blutfluß ; Regionales zerebrales Blutvolumen ; Key words Cerebral glioma ; Xenon CT ; Perfusion MRI ; Astrocytoma Regional cerebral blood flow ; Regional cerebral blood volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Within certain limits the vascularity of cerebral gliomas correlates with dysplasia. Xenon CT and perfusion MRI can be used to investigate tumor vascularity. Using an optimized wash in/out protocol with inhalation of 30% xenon gas, xenon CT was performed and regional cerebral blood flow (rCBF) and blood/tissue partition coefficient (λ) calculated. Furthermore, perfusion MRI was performed using a dynamic T2*w EPI sequence with intravenous administration of Gd-DTPA. The relative regional cerebral blood volume, arrival time, time to peak and mean transit time were calculated. Both modalities were used in patients with supratentorial gliomas and compared with conventional contrast-enhanced MRI (ceMRI). Calculation of regional cerebral blood flow, as compared to ceMRI, did not contribute to the diagnostic approach of tumor dysplasia. Tumour vascularity was better estimated by measurement of λ. Measurement of relative regional cerebral blood volume also correlated with tumor vascularity. Mainly the possibility of direct quantification of the Xe-CT data was advantagenous compared to perfusion MRI, and the XeCT data could be interpreted more clearly. Further upgrades of the technical equipment of MR as well as upgrades of available software will increase the applicability of perfusion MRI. However, both modalities offer a more precise investigation of tumor vascularization compared to ceMRI since potential dysplastic alteration may be detected earlier, which will be advantageous for planning bioptical approach of such tumours.
    Notes: Zusammenfassung Die Vaskularisation eines zerebralen Glioms korreliert, innerhalb bestimmter Grenzen, mit dem Grad der Dysplasie. Xenon-CT und Perfusionskernspintomographie (Perfusions-KST) können zur genaueren Diagnostik der Tumorvaskularisation eingesetzt werden. Die Xenon-CT wurde unter Verwendung eines optimierten Wash-in-out-Protokolls unter Inhalation von 30% Xenongas durchgeführt und der regionale zerebrale Blutfluß sowie der Blut-Gewebe-Verteilungskoeffizient berechnet. Für die Perfusions-KST fand eine dynamische T2*-gewichtete EPI-Sequenz während der i.v. Applikation von Kontrastmittel Verwendung. Das relative, regionale zerebrale Blutvolumen, die Bolusankunftszeit, der Bolusmaximumzeitpunkt und die mittlere Bolustransitzeit wurden ermittelt. Beide Verfahren wurden bei Patienten mit supratentoriellen Gliomen eingesetzt und die bisherigen Daten mit der konventionellen Kontrastmittel-verstärkten KST (KM-KST) verglichen. Diskussion: Die Bestimmung des regionalen zerebralen Blutflusses allein ergibt keinen Vorteil gegenüber der KM-KST. Der Blut-Gewebe-Verteilungskoeffizient ermöglicht jedoch eine genauere Beurteilung der Tumorvaskularisation. Die Messung des regionalen zerebralen Blutvolumens erfaßt die Tumorvaskularisation ebenfalls zufriedenstellend. Die Ergebnisse der XeCT waren jedoch, aufgrund der einfacheren Quantifizierbarkeit, eindeutiger interpretierbar als jene der Perfusions-KST. Von technischen Aufrüstungen des MR-Tomographen und Erweiterungen des Software-Sets sind jedoch Verbesserungen der Ergebnisse der Perfusions-KST gegenüber der Xenon-CT zu erwarten. Beide Methoden bieten eine genauere Untersuchungsmöglichkeit der Tumorvaskularisation, etwa zur Lokalisation dysplastischer Foci vor Biopsien als die konventionelle KM-KST, da punktuell dysplastische, vaskuläre Veränderungen früh erfaßt werden können.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050444
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