Sven Mutze

Blunt Liver Injuries in Polytrauma: Results from a Cohort Study with the Regular Use of Whole-body Helical Computed Tomography

The estimated prevalence of liver injury in patients with blunt multiple trauma ranges from 1% to 8%. The objective of this study was to investigate the profile of accompanying liver injury in a cohort of polytraumatized patients who had regularly undergone contrast-enhanced, whole-body helical computed tomography (CT). We enrolled consecutive patients admitted between September 1997 and January 2001 to a level I trauma center. Clinical baseline data were compiled as part of a nationwide trauma registry. Morphologic features were evaluated descriptively, whereas prognostic variables were assessed by logistic regression analysis. We identified 218 patients [149 men, mean age 35 ± 18 years, mean injury severity score (ISS) 35 ± 10], 55 of whom had sustained blunt liver trauma [25.2%, 95% confidence interval (CI) 19.6–31.5%]. The prevalence of Moore III to V lesions was 10.1%. There were 99 parenchymal contusions, 15 capsular tears, and 2 liver fractures. Surgery was required in 15 patients and was best predicted by the classification of the American Association for the Surgery of Trauma [odds ratio (OR) 3.91, 95% CI 1.59–9.61]. The mortality rate was 0.0035/person/day. Patients requiring surgical repair had fourfold increased relative odds of case fatality (OR 4.50, 95% CI 1.01–19.96). Sevenfold increased relative odds were observed if liver laceration was considered the leading injury (OR 7.17, 95% CI 1.17–43.97). The prevalence of liver lacerations among multiple-trauma patients is likely to be underestimated and must be determined by the independent application of reference standards, such as helical CT. High-grade hepatic injuries and the need for surgical repair are associated with poorer survival prognosis.

Use of contrast-enhanced MR imaging to detect sacroiliitis in children.

Abstract Purpose. To verify the diagnostic value of contrast-enhanced MR imaging compared with conventional radiography in the diagnosis of sacroiliitis in children. Design and patients. Radiography and MR imaging of the sacroiliac joints were performed in 185 children subdivided into the following groups according to the modified European Spondyloarthropathy (SpA) Study Group (ESSG) criteria: group 1, undifferentiated spondyloarthropathy (uSpA) (n=53, 94.5% HLA-B27+); group 2, differentiated SpA (n=45, 93.3% HLA-B27+); group 3, patients with no signs of SpA other than oligoarthritis (n=39, 92.3% HLA-B27+); group 4, HLA-B27+ controls with various other non-SpA diagnoses (n=22); and group 5, HLA-B27– controls with various other non-SpA diagnoses (n=26). Radiographs were evaluated on the basis of the modified New York criteria independently by three experienced radiologists masked to the clinical data. In a second step, the same radiologists independently evaluated the MR images without knowledge of the clinical data and radiographic findings using the recently published criteria developed by our group. These criteria allow differentiation of acute and chronic inflammatory changes. Results. Radiography demonstrated sacroiliitis in 18 patients: 4 of 53 in group 1 (7.5%), 14 of 45 in group 2 (31%), but none in groups 3, 4 and 5. In contrast, MR imaging demonstrated acute and/or chronic sacroiliitis in 44 patients: 18 of 53 in group 1 (34%), 21 of 45 in group 2 (46.7%) and 5 of 39 in group 3 (12.8%), but none in groups 4 and 5. The percentage of sacroiliitis detected by MR imaging was significantly higher than that detected by radiography (P<0.001). Conclusion. Contrast-enhanced MR imaging is a useful method for detecting sacroiliitis in children. Advantages of contrast-enhanced MR imaging compared with conventional radiography are a higher sensitivity due to the ability to document early and acute changes and the absence of radiation exposure.

Die klinische Wertigkeit des ISO-C3D bei der Osteosynthese des Fersenbeins

ZusammenfassungIn einer prospektiven Studie mit 82 konsekutiven Patienten bei denen eine operative Versorgung einer intraartikulären Fersenbeinfraktur erfolgte, wurde ein Qualitätsvergleich zwischen konventioneller Durchleuchtung, intraoperativer Iso-C3D- und postoperativer CT-Bildgebung angestellt. Die in drei Sektoren eingeteilte Facies articularis talaris posterior (FATP) wurde von zwei unabhängigen Untersuchern auf verbliebene Gelenkstufen und fracture gaps untersucht. Analysiert wurde, ob der Operateur die ISO-C3D-Schnittbilder richtig befundete und intraoperativ Konsequenzen daraus zog. Es fanden sich keine signifikanten Unterschiede bei der Befundungssicherheit zwischen Iso-C3D- und CT-Bildgebung bezüglich verbliebener Gelenkstufen in den Sektoren I–III, sowie detektierter fracture gaps in den Sektoren I und III. Mit der konventionellen Durchleuchtung waren die Sektoren I und II überhaupt nicht zu beurteilen. In 6 Fällen (7,3%) wurde die Reposition intraoperativ nach einem Iso-C3D-Scan optimiert. Bei 10 Patienten wurden 12 Schraubenfehllagen (12,2% bzw. 14,6%) korrigiert. Die Ergebnisse zeigen, dass mit der intraoperativen Iso-C3D-Bildgebung eine hohe Befungssicherheit zu erreichen ist. Der Operateur erhält relevante Zusatzinformationen, die zu einer Änderung der OP-Strategie führen können. AbstractWe compared in a prospective study including 82 patients treated with ORIF of an intraarticular calcaneus fracture the quality of fluoroscopy, intraoperatively Iso-C3D and postoperative CT-scans. Therefore the posterior facet of the calcaneus (PFOC) was divided into three sectors. Joint steps and fracture gaps were detected by two independent investigators and statistically analysed. Another focus was to evaluate if the findings due to intraoperatively Iso-C3D assessment performed by the surgeon were correct and subsequently influenced the surgical procedure. There were no statistically differences between the Iso-C3D- and CT findings concerning joint steps or fracture gaps in PFOC sectors I–III. With fluoroscopy an assessment of the PFOC sectors I and II was not possible. In six cases (7.3%), intraoperative reduction was redone after performing an Iso-C3D scan. In ten cases, 12 malpositioned screws were replaced (12.2%/14.6%). These results suggest that intraoperative 3D Iso-C3D imaging provides a high diagnostic reliability. By careful assessment of the images the surgeons receive information which could lead to a change of the operative strategy.

[The clinical use of the ISO-C(3D) imaging system in calcaneus fracture surgery].

ZusammenfassungIn einer prospektiven Studie mit 82 konsekutiven Patienten bei denen eine operative Versorgung einer intraartikulären Fersenbeinfraktur erfolgte, wurde ein Qualitätsvergleich zwischen konventioneller Durchleuchtung, intraoperativer Iso-C3D- und postoperativer CT-Bildgebung angestellt. Die in drei Sektoren eingeteilte Facies articularis talaris posterior (FATP) wurde von zwei unabhängigen Untersuchern auf verbliebene Gelenkstufen und fracture gaps untersucht. Analysiert wurde, ob der Operateur die ISO-C3D-Schnittbilder richtig befundete und intraoperativ Konsequenzen daraus zog. Es fanden sich keine signifikanten Unterschiede bei der Befundungssicherheit zwischen Iso-C3D- und CT-Bildgebung bezüglich verbliebener Gelenkstufen in den Sektoren I–III, sowie detektierter fracture gaps in den Sektoren I und III. Mit der konventionellen Durchleuchtung waren die Sektoren I und II überhaupt nicht zu beurteilen. In 6 Fällen (7,3%) wurde die Reposition intraoperativ nach einem Iso-C3D-Scan optimiert. Bei 10 Patienten wurden 12 Schraubenfehllagen (12,2% bzw. 14,6%) korrigiert. Die Ergebnisse zeigen, dass mit der intraoperativen Iso-C3D-Bildgebung eine hohe Befungssicherheit zu erreichen ist. Der Operateur erhält relevante Zusatzinformationen, die zu einer Änderung der OP-Strategie führen können. AbstractWe compared in a prospective study including 82 patients treated with ORIF of an intraarticular calcaneus fracture the quality of fluoroscopy, intraoperatively Iso-C3D and postoperative CT-scans. Therefore the posterior facet of the calcaneus (PFOC) was divided into three sectors. Joint steps and fracture gaps were detected by two independent investigators and statistically analysed. Another focus was to evaluate if the findings due to intraoperatively Iso-C3D assessment performed by the surgeon were correct and subsequently influenced the surgical procedure. There were no statistically differences between the Iso-C3D- and CT findings concerning joint steps or fracture gaps in PFOC sectors I–III. With fluoroscopy an assessment of the PFOC sectors I and II was not possible. In six cases (7.3%), intraoperative reduction was redone after performing an Iso-C3D scan. In ten cases, 12 malpositioned screws were replaced (12.2%/14.6%). These results suggest that intraoperative 3D Iso-C3D imaging provides a high diagnostic reliability. By careful assessment of the images the surgeons receive information which could lead to a change of the operative strategy.

Accuracy of single-pass whole-body computed tomography for detection of injuries in patients with major blunt trauma

Background: Contrast-enhanced whole-body computed tomography (also called “pan-scanning”) is considered to be a conclusive diagnostic tool for major trauma. We sought to determine the accuracy of this method, focusing on the reliability of negative results. Methods: Between July 2006 and December 2008, a total of 982 patients with suspected severe injuries underwent single-pass pan-scanning at a metropolitan trauma centre. The findings of the scan were independently evaluated by two reviewers who analyzed the injuries to five body regions and compared the results to a synopsis of hospital charts, subsequent imaging and interventional procedures. We calculated the sensitivity and specificity of the pan-scan for each body region, and we assessed the residual risk of missed injuries that required surgery or critical care. Results: A total of 1756 injuries were detected in the 982 patients scanned. Of these, 360 patients had an Injury Severity Score greater than 15. The median length of follow-up was 39 (interquartile range 7–490) days, and 474 patients underwent a definitive reference test. The sensitivity of the initial pan-scan was 84.6% for head and neck injuries, 79.6% for facial injuries, 86.7% for thoracic injuries, 85.7% for abdominal injuries and 86.2% for pelvic injuries. Specificity was 98.9% for head and neck injuries, 99.1% for facial injuries, 98.9% for thoracic injuries, 97.5% for abdominal injuries and 99.8% for pelvic injuries. In total, 62 patients had 70 missed injuries, indicating a residual risk of 6.3% (95% confidence interval 4.9%–8.0%). Interpretation: We found that the positive results of trauma pan-scans are conclusive but negative results require subsequent confirmation. The pan-scan algorithms reduce, but do not eliminate, the risk of missed injuries, and they should not replace close monitoring and clinical follow-up of patients with major trauma.

Normal morphology of sacroiliac joints in children : magnetic resonance studies related to age and sex

Abstract Objective. To determine in a prospective study the normal MRI morphology of the sacroiliac joints (SIJs) in relation to age and sex during adolescence. Design and patients. A total of 98 children (63 boys, mean age 12.7±2.8 years; 35 girls, mean age 13.7±2.3 years), ranging in age from 8 to 17 years, with juvenile chronic arthritis (JCA) but without signs of sacroiliitis fulfilled the study prerequisites (no back pain and no pathologic changes of the SIJs on physical examination before MRI in a 1.5-year follow-up). An additional eight HLA-B27-negative boys and eight HLA-B27-negative girls without arthritis served as controls. The MRI protocol comprised a T1-weighted SE sequence, an opposed-phase T2*-weighted GE sequence, and a dynamic contrast-enhanced study in single-section technique. Results. Noncontrast MRI permitted differentiation of “open” from ossified segmental and lateral apophyses of the sacral wings, with a significant difference in age (P <0.05) between children with open and ossified apophyses. Ossification of the apophyses of the sacral wings was seen significantly earlier (P <0.05) in girls than in boys. Girls also had a significantly higher incidence of transitional lumbosacral vertebrae, pelvic asymmetries, and accessory joints. In the contrast-enhanced opposed-phase MRI study, normal cartilage of the SIJs showed no contrast enhancement whereas the joint capsule showed a moderate enhancement. Conclusion. There are significant age- and sex-related differences in the normal MRI morphology of juvenile SIJs. Our findings might serve as a standard of comparison for the evaluation of pathologic changes – in particular for the early identification of juvenile sacroiliitis.

MRI scanning and incus fixation in vibrant soundbridge implantation.

Objective: Presentation of patient data after Vibrant Sound-bridge (VS) implantation/explantation with respect to magnetic resonance imaging (MRI) compatibility and stability of incus fixation of the implant. Study design: In a retrospective case review, we report on two patients who had to be diagnosed by cranial MRI scans after previous implantation of a VS. Moreover, in one of these cases, the incus was removed after explantation of the VS because of a peripheral hearing loss. This enabled a microscopic evaluation of the incus. At the long process of the incus, the floating mass transmitter (FMT) has been fixed for 4 years. Setting: Tertiary referral center. Subjects: Two patients who fulfilled, at the time of implantation, the criteria for implantation of a VS. Results: In both cases, no demagnetization of the external magnet nor of the FMT were found. Device function after the MRI scans were normal. Pure-tone audiometric thresholds remained unchanged after the MRI scanning and the scanning-related magnetic forces. In both cases, the FMT fixation of the incus was found to be regular. In one case, the fixation was checked by an additional tympanoscopy 1 year after the implantation, and in the other case it was assessed by recording the functional gain of the VS (which was normal) after the MRI scanning. One patient complained about a transient hyperacuity due to the loudness during the MRI scanning procedure. MRI scans showed a blackening of the implant area with spherical distortions of the picture. Conclusion: Although MRI scanning (at 1.5 tesla [T]) with the FMT in place did not lead to adverse effects in the two patients, systematic in vitro studies are required to determine a possible magnetization threshold that could impair the VS function when MRI scans are applied in those patients. The microscopically observed erosions of the long process of the incus after 4 years of FMT clamp fixation show similarities to findings after stapes revision surgery. However, this limited experience in one case does not allow us to make conclusions on the long-term stability of the incus fixation.

Die Wertigkeit der Magnetresonanztomografie (MRT) bei der Diagnostik von Übergangsfrakturen im Bereich der distalen Tibia

ZusammenfassungZur Untersuchung der Frage, in welcher Hinsicht ein mehrdimensionales bildgebendes Verfahren konventionellen Röntgenbildern bei der Diagnostik multiplanarer Übergangsfrakturen überlegen ist, wurde in einem Zeitraum von 18 Monaten bei 15 Frakturen im Bereich der distalen Tibia, bei denen im konventionellen Röntgenbild der Verdacht auf eine Epiphysenfugenbeteiligung bestand, eine MRT durchgeführt, mit der eine röntgenstrahlenfreie, mehrdimensionale Darstellung der verletzten Region möglich ist.Anschließend wurden MRT- und Röntgenbilder dieser Patienten anonymisiert und von 4 unabhängigen Befundern hinsichtlich des Frakturtyps, des Frakturverlaufes und der Frakturdislokation befundet.Die Diagnose der Übergangsfraktur wurde in beiden bildgebenden Verfahren bei 12 von 15 Patienten korrekt gestellt.Die Standardröntgenaufnahmen zeigten sich jedoch der MRT bei der Befundung der Übergangsfrakturen hinsichtlich der oben genannten Kriterien deutlich unterlegen. In den Nativröntgenaufnahmen wurde der Frakturtyp in 2 Fällen fehlklassifiziert, 2 von 3 Rotationsfehlern wurden übersehen, des Weiteren kam es zu Fehlinterpretationen der maximalen Fragmentdislokation von durchschnittlich 0,5 mm.Zur exakten Befunderhebung von Übergangsfrakturen bedarf es eines zusätzlichen, mehrdimensionalen, bildgebenden Verfahrens. Dabei ist die MRT der konventionellen Röntgendiagnostik aufgrund fehlender Strahlenbelastung sowie der Möglichkeit der Beurteilung von ligamentären und kartilaginären Läsionen überlegen.AbstractThe rare transitional fractures occur in adolescents at a time of incomplete desis of the epiphysis. The anatomy of this fracture type is complex with the fracture line running in multiple planes. Conventional plain film radiographs often underestimate the extent and geometry of the fracture due to its transverse components.This study was performed to asses the benefit of MR-imaging compared to plain film radiographs in diagnosis and analysis regarding fracture-type, anatomy and dislocation of fracture.During a time period of 18 months we treated 15 patients with a fracture of the distal tibial epiphysis. In addition to plain film radiographs they got MRI of the distal tibia. Plain film radiographs and MRI were anonymized and diagnosed by 2 surgeons and 2 radiologists.12 transitional fractures were diagnosed in plain radiographs as well as MRI, but regarding our criteria as above, we found two wrong classifications of fracture-type, an underestimation of fracture dislocation of an average of 0,5 mm in plain film radiographs and two rotational dislocations were missed.The MRI was found to provide anatomical detail and information superior to plain film radiographs.

MRI Artifacts and Cochlear Implant Positioning at 3 T In Vivo.

Hypothesis To evaluate the assessment of the internal auditory canal and the labyrinth in relation to different CI magnet positions and MRI sequences at 3 T. Background The indication criteria for cochlear implantation have been changed over the years and the growing number of implantations in patients after acoustic neuroma resections underline the importance of a postoperative MR imaging to assess the internal auditory canal (IAC) and the labyrinth. The MRI artifact induced by the cochlear implant magnet is a known problem that should be further observed by this investigation. Methods We compared the artifacts of Cochlear 512 magnets at different head positions in vivo at 3 T. The observed positions varied with a nasion-external ear canal angle of 90, 120, and 160 degrees and a variable distance of 5, 7, and 9 cm in relation to the external ear canal and different MRI sequences. Results The complete assessment of the internal auditory canal and labyrinth was possible with a magnet positioned at 90 degrees and 9 cm and 160 degrees and 9 cm. Evaluation of the IAC alone was possible with magnet positions at 90 degrees and 7 cm and 9 cm, 120 degrees and 9 cm, and 160 degrees and 7 cm and 9 cm. A high-resolution 3D T2w Drive sequence decreased the visibility of the structures significantly. A high-resolution TSE 2D T2w sequence together with one of the above-described positions allowed sufficient visualization of the structures. Conclusion The position of the implant and the MRI sequence used determine the assessment of the IAC and the labyrinth at 3 T MRI. A position of the implant magnet at a nasion-external auditory canal angle which is more horizontal and posterior than so far commonly used allows a better visualization of the IAC and the labyrinth at 3 T.

Role of magnetic resonance imaging in the diagnosis of distal tibia fractures in adolescents.

This prospective study was performed to assess the benefits of magnetic resonance imaging (MRI) compared with plain radiographs in the diagnosis and analysis of transitional fractures in terms of fracture type, anatomy, and dislocation. During a 24-month period, 22 adolescents with a fracture of the distal tibial epiphysis were treated. In addition to plain film radiographs, MR images of the distal tibia were also obtained. Plain film radiographs and MR images were randomized and diagnosed by two surgeons and two radiologists. Fifteen transitional fractures were diagnosed using plain radiographs, while 17 transitional fractures could be found with MRI. Fracture type was misclassified, fracture displacement was underestimated in general, and rotational displacements were not visualized on plain film radiographs. MRI was found to provide anatomic detail and information superior to plain film radiographs.