Max-Ludwig Schäfer

Reducing Radiation Dose in Emergency CT Scans While Maintaining Equal Image Quality: Just a Promise or Reality for Severely Injured Patients?

Objective. This study aims to assess the impact of adaptive statistical iterative reconstruction (ASIR) on CT imaging quality, diagnostic interpretability, and radiation dose reduction for a proven CT acquisition protocol for total body trauma. Methods. 18 patients with multiple trauma (ISS ≥ 16) were examined either with a routine protocol (n = 6), 30% (n = 6), or 40% (n = 6) of iterative reconstruction (IR) modification in the raw data domain of the routine protocol (140 kV, collimation: 40, noise index: 15). Study groups were matched by scan range and maximal abdominal diameter. Image noise was quantitatively measured. Image contrast, image noise, and overall interpretability were evaluated by two experienced and blinded readers. The amount of radiation dose reductions was evaluated. Results. No statistically significant differences between routine and IR protocols regarding image noise, contrast, and interpretability were present. Mean effective dose for the routine protocol was 25.3 ± 2.9 mSv, 19.7 ± 5.8 mSv for the IR 30, and 17.5 ± 4.2 mSv for the IR 40 protocol, that is, 22.1% effective dose reduction for IR 30 (P = 0.093) and 30.8% effective dose reduction for IR 40 (P = 0.0203). Conclusions. IR does not reduce study interpretability in total body trauma protocols while providing a significant reduction in effective radiation dose.

Comparison Between Amputation-Induced Demineralization and Age-Related Bone Loss Using Digital X-Ray Radiogrammetry

Digital X-ray radiogrammetry (DXR) is a computer-assisted automatic osteodensitometric tool. This study was performed to compare DXR measurements between bone changes following amputation trauma and age-related bone loss. Thirty-five men, who had undergone finger amputations, received a baseline examination and 2--3 serial measurements. As a second group, 215 males older than 70yr were enrolled. All patients obtained standardized hand radiographs. The following DXR parameters evaluating metacarpals were considered: cortical bone mineral density (DXR-BMD), cortical thickness (DXR-CT), metacarpal index (DXR-MCI), outer bone diameter (width; DXR-W), and inner medullary diameter (DXR-MD). In the amputation group, the DXR parameters showed an accentuated initial decrease between first and second measurements (DRX-BMD--12.7%, DXR-CT--14.2%, DXR-W--8.6%, DXR-MCI--6.1%; p<0.001) followed by a less pronounced reduction between second and third radiographs (DRX-BMD--0.5%, DXR-CT--1.5%, DXR-W--0.1%, DXR-MCI--1.3%). DXR-MD revealed a reduction of--3.6% (p<0.05) between first and second estimates and a non-significant increase (+1.1%) between second and third measurements. When compared with the second and third estimates in the amputation group, men older than 70yr presented lower DXR-BMD, DXR-CT, and DXR-MCI values (p<0.001), but larger metacarpal outer and inner bone diameters (DXR-W and DXR-MD; p<0.001). DXR-MD of the elderly men group was also more extended when compared with the baseline measurements of the amputation cohort (p<0.001). The early accentuated cortical bone loss and particularly the pronounced decrease of the outer bone width seem to be characteristic for amputation-induced osteoporosis, suggesting that this might be a distinct secondary osteoporosis entity. When compared with amputation-associated osteoporosis, where the bone loss occurs to a higher extent in the outer bone diameter than in the medullary cavity, the age-related bone changes lead more to an increase of the medullary diameter than of the outer bone width.

Glioblastoma multiforme versus solitary supratentorial brain metastasis: differentiation based on morphology and magnetic resonance signal characteristics.

PURPOSE To evaluate the diagnostic potential of a multi-factor analysis of morphometric parameters and magnetic resonance (MR) signal characteristics of a mass and peritumoral area to distinguish solitary supratentorial metastasis from glioblastoma multiforme (GBM). MATERIALS AND METHODS MR examinations of 51 patients with histologically proven GBM and 44 with a single supratentorial metastasis were evaluated. A large variety of morphologic criteria and MR signal characteristics in different sequences were analyzed. The data were subjected to logistic regression to investigate their ability to discriminate between GBM and cerebral metastasis. Receiver-operating characteristic (ROC) analysis was used to select an optimal cut-off point for prediction and to assess the predictive value in terms of sensitivity, specificity, and accuracy of the final model. RESULTS The logistic regression analysis revealed that the ratio of the maximum diameter of the peritumoral area measured on T2-weighted images (d T2) to the maximum diameter of the enhancing mass area (d T1, post-contrast) is the only useful criterion to distinguish single supratentorial brain metastasis from GBM with a lower ratio favoring GBM (accuracy 68 %, sensitivity 84 % and specificity 45 %). The cut-off point for the ratio d T2/d T1 post-contrast was calculated as 2.35. CONCLUSION Measurement of maximum diameters of the peritumoral area in relation to the enhancing mass can be evaluated easily in the clinical routine to discriminate GBM from solitary supratentorial metastasis with an accuracy comparable to that of advanced MRI techniques.

Cross Sectional Imaging of Solitary Lesions of the Neurocranium

Background Although a wide range of processes along the neurocranium are of a benign nature, there are often difficulties in the differential diagnosis. Method In the review CT/MRI scans of the head were evaluated retrospectively regarding solitary lesions along the neurocranium. The majority of the lesions were histologically proven. Results The purpose of the review is to present typical pathologies of the neurocranium and provide a systematic overview based on 12 entities, their locations, prevalence and radiological characteristics. Conclusion Processes, which primarily originate from the neurocranium have to be differentiated from secondary processes infiltrating the neurocranium. For this important diagnostic feature, MRI is typically essential, while the definitive diagnosis is often made on the basis of the medical history and the typical appearance on computer tomography. Key Points  · There are often difficulties in the precise differential diagnosis of solitary lesions along the neurocranium. Typical solitary pathologies of the neurocranium based on 12 entities were presented. Both magnetic resonance imaging and computed tomography are often essential for an exact differential diagnosis.. Citation Format · Schäfer M, Koch A, Streitparth F et al. Cross Sectional Diagnosis of Solitary Lesions of the Neurocranium. Fortschr Röntgenstr 2017; 189: 1135 - 1144.

Darstellung der Gelenkspaltweite der Proximalen Interphalangeal Gelenke in Abhängigkeit von Alter und Geschlecht an einem kaukasischen Normkollektiv

Ziele: Die Computer-Assistierte Gelenkspaltweitenmessung (CAJSA) stellt ein semi-automatisches Verfahren zur Messung der Gelenkspaltweiten im Bereich der Fingergelenke dar. Im Rahmen dieser Studie erfolgte die geschlechts- und alterspezifische Quantifizierung der Gelenkspaltweite der Proximalen Interphalangeal-Gelenke (JSD-PIP). Methode: Es erfolgte die Bestimmung der Gelenkspaltweite der Proximalen Interphalangeal-Gelenke II-V (PIP) durch die CAJSA (Radiogrammetry Kit, Version 1.3.6, Sectra, Schweden) an Handrontgenaufnahmen von 869 gesunden deutschen Probanden (Frauen: n=351, Manner: n=518). Die Gelenkspaltweite der PIP-Gelenke II-V (JSD in cm) wurde als mittlere Gelenkspaltweite (JSD-PIP mean) angegeben. Im weiteren erfolgte die Auswertung der Gelenkspaltweite nach Geschlecht und Alter. Ergebnis: Fur das Gesamtkollektiv konnte eine signifikante Abnahme der Gelenkspaltweite zwischen der Altersgruppe 90 Jahre verifiziert werden (Manner: -55.0%, Frauen: -44.4%). Die jahrliche Gelenkspaltverminderung betrug -2.2% fur Frauen und -2.0% fur Manner bis zum Alter von 25 Jahren. Der JSD-PIP zeigt ab dem Alter von 26 Jahren eine prolongierte jahrliche Reduktion (Frauen: -0.3%, Manner -0.5%). Im Vergleich zum mannlichen Kollektiv wies die weibliche Gruppe in allen Altergruppen einen signifikant schmaleren JSD-PIP mit -15.4% auf. Schlussfolgerung: Die Entwicklung der semi-automatischen Gelenkspaltmessung mittels CAJSA ermoglicht die Quantifizierung der Gelenkspaltweite bei peripheren Handgelenkserkrankungen (e.g. Osteoarthritis und rheumatoide Arthritis). Im Rahmen dieser Studie konnte die alterspezifische Gelenkspaltweitenreduktion des JSD-PIP an einem gesunden Kollektiv von gesunden Deutschen nachgewiesen werden. Des Weiteren zeigte das weibliche Kollektiv durchgehend eine signifikant geringere Gelenkspaltweite fur die JSD-PIP. Somit konnte mittels CAJSA erstmalig der Einfluss von Alter und Geschlecht auf die Gelenkspaltweite der PIP-Gelenke quantifiziert werden. Korrespondierender Autor: Pfeil A Friedrich-Schiller-Universitat Jena, Institut fur Diagnostische und Interventionelle Radiologie, Erlanger Allee 101, 07747 Jena E-Mail: alexander.pfeil@med.uni-jena.de