Seit Beginn des neuen Jahrtausends haben Tablets in der medizinischen Lehre zunehmend an Bedeutung gewonnen. In dieser Studie wurden ein Tablet-basiertes und ein Dozierenden-zentriertes Lehrformat im Rahmen eines Radiologie-Seminars verglichen. Ziel war es, vergleichende Erkenntnisse über selbsteingeschätzten und objektiven Lernzuwachs und empfundene didaktische Qualität zu erlangen und mögliche Einflüsse des Charismas der Dozierenden sowie der studentischen Technikaffinität auf diese Variablen zu untersuchen. Von n=366 Studierenden wurden über drei Semester hinweg Daten zu studentischer Technikaffinität generell sowie didaktischer Qualität und Zufriedenheit mit den Seminaren abhängig vom Lehrformat erhoben. Im letzten Studiensemester nahmen die Studierenden zudem eine Selbsteinschätzung ihres Lernzuwachses vor und legten ein Wissens- und Bildinterpretationstestat sowie eine Einschätzung des Charismas der Dozierenden ab. Mittels Maximum-Likelihood Faktorenanalyse erfolgte eine Strukturaufklärung der didaktischen Qualität und des Charismas. Pearson-Korrelationskoeffizienten wurden zur Untersuchung möglicher Korrelationen zwischen den Variablen berechnet. Ein Strukturregressionsmodell des Charismas der Dozierenden, der studentischen Technikaffinität und der didaktischen Qualität wurde erstellt und daraus eine lineare Regressionsgleichung abgeleitet. Dem Tablet-basierten Lehrformat wurden signifikant höhere Werte in didaktischer Qualität und studentischer Zufriedenheit zugeschrieben. Das Dozierenden-zentrierte Format schnitt hingegen in selbsteingeschätztem und objektivem Lernzuwachs signifikant besser ab. Ausschließlich im Tablet-basierten Unterricht korrelierte das Charisma der Dozierenden mit dem selbsteingeschätzten Lernzuwachs. Die studentische Technikaffinität wirkte sich in diesem Format stärker auf die didaktische Qualität aus. Zudem wurden gute Organisation, eindeutige Lernziele und adäquate Lernformvariation als bedeutsame Faktoren identifiziert. Diese Studie hebt die Relevanz des dozentischen Charismas und der studentischen Technikaffinität für die Sicherstellung hoher didaktischer Qualität in Tablet-basiertem Unterricht hervor. Sie zeigt zudem die Wichtigkeit der Kongruenz von Lernzielen, Lehrkonzept und Prüfungsmethode dieses Lehrformats auf, um hohe Studienleistungen sicherzustellen. Die untersuchten Faktoren sollten bei Entwurf digitaler Lehrkonzepte über spezifische Messinstrumente objektiviert und bei Bedarf geschult oder angepasst werden, um eine erfolgreiche Integration digitaler Medien in die medizinische Lehre zu gewährleisten.

Importance Squamous cell carcinoma (SCC) of the oral cavity is one of the most common tumor entities worldwide. Precise initial staging is necessary to determine a diagnosis, treatment, and prognosis. Objective To examine the diagnostic accuracy of preoperative 18-F fluorodeoxyglucose (FDG) positron emission tomographic/computed tomographic (PET/CT) imaging in detecting cervical lymph node metastases. Design, Setting, and Participants This prospective diagnostic study was performed at a single tertiary reference center between June 1, 2013, and January 31, 2016. Data were analyzed from April 7, 2018, through May 31, 2019. Observers of the FDG PET/CT imaging were blinded to patients’ tumor stage. A total of 150 treatment-naive patients with clinical suspicion of SCC of the oral cavity were enrolled. Exposures All patients underwent FDG PET/CT imaging before local tumor resection with selective or complete neck dissection. Main Outcomes and Measures The accuracy of FDG PET/CT in localizing primary tumor, lymph node, and distant metastases was tested. Histopathologic characteristics of the tissue samples served as the standard of reference. Results Of the 150 patients enrolled, 135 patients (74 [54.8%] men) with a median age of 63 years (range, 23-88 years) met the inclusion criteria (histopathologically confirmed primary SCC of the oral cavity/level-based histopathologic assessment of the resected lymph nodes). Thirty-six patients (26.7%) in the study cohort had neck metastases. Use of FDG PET/CT detected cervical lymph node metastasis with 83.3% sensitivity (95% CI, 71.2%-95.5%) and 84.8% specificity (95% CI, 77.8%-91.9%) and had a negative predictive value of 93.3% (95% CI, 88.2%-98.5%). The specificity was higher than for contrast-enhanced cervical CT imaging (67.0%; 95% CI, 57.4%-76.7%; P < .01) and cervical magnetic resonance imaging (62.6%; 95% CI, 52.7%-72.6%; P < .001). Ipsilateral lymph node metastasis in left- or right-sided primary tumor sites was detected with 78.6% sensitivity (95% CI, 63.4%-93.8%) and 83.1% specificity (95% CI, 75.1%-91.2%), and contralateral metastatic involvement was detected with 66.7% sensitivity (95% CI, 28.9%-100.0%) and 98.6% specificity (95% CI, 95.9%-100.0%). No distant metastases were observed. Conclusions and Relevance In this study, FDG PET/CT imaging had a high negative predictive value in detecting cervical lymph node metastasis in patients with newly diagnosed, treatment-naive SCC of the oral cavity. Routine clinical use of FDG PET/CT might lead to a substantial reduction of treatment-related morbidity in most patients.

Abstract To compare intravenous contrast material (CM) injection protocols for dual-energy CT pulmonary angiography (CTPA) in patients with suspected acute pulmonary embolism with regard to image quality and pulmonary perfused blood volume (PBV) values. A total of 198 studies performed with four CM injection protocols varying in CM volume and iodine delivery rates (IDR) were retrospectively included: (A) 60 ml at 5 ml/s (IDR = 1.75gI/s), (B) 50 ml at 5 ml/s (IDR = 1.75gI/s), (C) 50 ml at 4 ml/s (IDR = 1.40gI/s), (D) 40 ml at 3 ml/s (IDR = 1.05gI/s). Image quality and PBV values at different resolution settings were compared. Pulmonary arterial tract attenuation was highest for protocol A (397 ± 110 HU; p vs. B = 0.13; vs. C = 0.02; vs. D < 0.001). CTPA image quality of protocol A was rated superior compared to protocols B and D by reader 1 (p = 0.01; < 0.001), and superior to protocols B, C and D by reader 2 (p < 0.001; 0.02; < 0.001). Otherwise, there were no significant differences in CTPA quality ratings. Subjective iodine map ratings did not vary significantly between protocols A, B, and C. Both readers rated protocol D inferior to all other protocols (p < 0.05). PBV values did not vary significantly between protocols A and B at resolution settings of 1, 4 and 10 (p = 0.10; 0.10; 0.09), while otherwise PBV values displayed a decreasing trend from protocol A to D (p < 0.05). Higher CM volume and IDR are associated with superior CTPA and iodine map quality and higher absolute PBV values.

The use of bone-cement-enforced osteosynthesis is a growing topic in trauma surgery. In this context, drillability is a desirable feature for cements that can improve fracture stability, which most of the available cement systems lack. Therefore, in this study, we evaluated a resorbable and drillable magnesium-phosphate (MgP)-based cement paste considering degradation behavior and biocompatibility in vivo. Two different magnesium-phosphate-based cement (MPC) pastes with different amounts of phytic acid (IP 6) as setting retarder (MPC 22.5 and MPC 25) were implanted in an orthotopic defect model of the lateral femoral condyle of New Zealand white rabbits for 6 weeks. After explantation, their resorption behavior and material characteristics were evaluated by means of X-ray diffraction (XRD), porosimetry measurement, histological staining, peripheral quantitative computed tomography (pQCT), cone-beam computed tomography (CBCT) and biomechanical load-to-failure tests. Both cement pastes displayed comparable results in mechanical strength and resorption kinetics. Bone-contact biocompatibility was excellent without any signs of inflammation. Initial resorption and bone remodeling could be observed. MPC pastes with IP 6 as setting retardant have the potential to be a valuable alternative in distinct fracture patterns. Drillability, promising resorption potential and high mechanical strength confirm their suitability for use in clinical routine.

This study was designed to investigate the image quality of ultra-high-resolution ankle arthrography employing a photon-counting detector CT. Bilateral arthrograms were acquired in four cadaveric specimens with full-dose (10 mGy) and low-dose (3 mGy) scan protocols. Three convolution kernels with different spatial frequencies were utilized for image reconstruction (ρ\(_{50}\); Br98: 39.0, Br84: 22.6, Br76: 16.5 lp/cm). Seven radiologists subjectively assessed the image quality regarding the depiction of bone, hyaline cartilage, and ligaments. An additional quantitative assessment comprised the measurement of noise and the computation of contrast-to-noise ratios (CNR). While an optimal depiction of bone tissue was achieved with the ultra-sharp Br98 kernel (S ≤ 0.043), the visualization of cartilage improved with lower modulation transfer functions at each dose level (p ≤ 0.014). The interrater reliability ranged from good to excellent for all assessed tissues (intraclass correlation coefficient ≥ 0.805). The noise levels in subcutaneous fat decreased with reduced spatial frequency (p &lt; 0.001). Notably, the low-dose Br76 matched the CNR of the full-dose Br84 (p 0.999) and superseded Br98 (p &lt; 0.001) in all tissues. Based on the reported results, a photon-counting detector CT arthrography of the ankle with an ultra-high-resolution collimation offers stellar image quality and tissue assessability, improving the evaluation of miniscule anatomical structures. While bone depiction was superior in combination with an ultra-sharp convolution kernel, soft tissue evaluation benefited from employing a lower spatial frequency.