Background As dental imaging accounts for approximately 40 % of all X-ray examinations in Germany, profound knowledge of this topic is essential not only for the dentist but also for the clinical radiologist. This review focuses on basic imaging findings regarding the teeth. Therefore, tooth structure, currently available imaging techniques and common findings in conserving dentistry including endodontology, periodontology, implantology and dental trauma are presented. Methods Literature research on the current state of dental radiology was performed using Pubmed. Results and Conclusion Currently, the most frequent imaging techniques are the orthopantomogram (OPG) and single-tooth radiograph, as well as computer tomography (CT) and cone beam CT mainly for implantology (planning or postoperative control) or trauma indications. Especially early diagnosis and correct classification of a dental trauma, such as dental pulp involvement, prevents from treatment delays or worsening of therapy options and prognosis. Furthermore, teeth are commonly a hidden focus of infection.Since radiologists are frequently confronted with dental imaging, either concerning a particular question such as a trauma patient or regarding incidental findings throughout head and neck imaging, further training in this field is more than worthwhile to facilitate an early and sufficient dental treatment. Key points Citation Format

¹⁷⁷Lutetium PSMA-617 (Lu-PSMA) therapy in patients with metastatic castration resistant prostate cancer (mCRPC) has gained visibility through the ongoing phase III trial. The data on prediction of therapy outcome and survival out of pretherapeutic imaging parameters is still sparse. In this study, the predictive and prognostic value of radiomic features from ⁶⁸Ga-PSMA-11 PET-MRI are analyzed. In total, 21 patients with mCRPC underwent ⁶⁸Ga-PSMA-11 PET-MRI before Lu-PSMA therapy. The PET-positive tumor volume was defined and transferred to whole-body T2-, T1- and contrast-enhanced T1-weighted MRI-sequences. The radiomic features from PET and MRI sequences were extracted by using a freely available software package. For selecting features that allow differentiation of biochemical response (PSA decrease > 50%), a stepwise dimension reduction was performed. Logistic regression models were fitted, and selected features were tested for their prognostic value (overall survival) in all patients. Eight patients achieved biochemical response after Lu-PSMA therapy. Ten independent radiomic features differentiated well between responders and non-responders. The logistic regression model, including the feature interquartile range from T2-weighted images, revealed the highest accuracy (AUC = 0.83) for the prediction of biochemical response after Lu-PSMA therapy. Within the final model, patients with a biochemical response (p = 0.003) and higher T2 interquartile range values in pre-therapeutic imaging (p = 0.038) survived significantly longer. This proof-of-concept study provides first evidence on a potential predictive and prognostic value of radiomic analysis of pretherapeutic ⁶⁸Ga-PSMA-11 PET-MRI before Lu-PSMA therapy.

Multispectral optoacoustic tomography (MSOT) represents a new imaging approach revealing functional tissue information without extrinsic contrast agents. Using a clinical combined ultrasound (US)/MSOT device, we investigated the interindividual robustness and impact of intra- and interobserver variability of MSOT values in soft tissue (muscle and subcutaneous fat) of healthy volunteers. Semiquantitative MSOT values for deoxygenated (Hb), oxygenated (HbO₂) and total hemoglobin (HbT), as well as oxygen saturation (sO₂), were calculated for both forearms in transversal and longitudinal probe orientation (n = 3, 8 measurements per subject). For intraobserver reproducibility, the same examiner investigated three subjects twice. Mean values of left vs. right forearm and transversal vs. longitudinal probe orientation were compared using an unpaired Student’s t test. Bland Altmann plots with 95% limits of agreement for absolute averages and differences were calculated. Intraclass correlation coefficients (ICC 2,k) were computed for three different examiners. We obtained reproducible and consistent MSOT values with small-to-moderate deviation for muscle and subcutaneous fat tissue. Probe orientation and body side had no impact on calculated MSOT values (p > 0.05 each). Intraobserver reproducibility revealed equable mean values with small-to-moderate deviation. For muscular tissue, good ICC was obtained for sO₂. Measurements of subcutaneous tissue revealed good-to-excellent ICCs for all calculated values. Thus, in this preliminary study on healthy individuals, clinical MSOT provided consistent and reproducible functional soft tissue characterization, independent on the investigating personnel.

Background: Transjugular intrahepatic portosystemic shunt (TIPS) implantation is an established procedure to treat portal hypertension with hepatic encephalopathy (HE) as a common complication. There is lack of evidence concerning HE prophylaxis after TIPS. Methods: N = 233 patients receiving TIPS between 2011 and 2018 at a German tertiary care center were included. Of them, 21% (n = 49) had a history of HE. The follow-up period was 12 months. The risk factors of post-TIPS HE were analyzed via multivariate analysis. The efficacy of prophylactic medication regimens was studied. The results show that 35.6% (n = 83) received no medication (NM), 36.5% (n = 85) received lactulose monoprophylaxis (LM), 2.6% (n = 6) rifaximin monoprophylaxis (RM) and 25.3% (n = 59) lactulose and rifaximin (LR) of which 64.4% received l-ornithin-l-aspartate (LOLA) additionally (LR + LOLA) and 36.6% did not (LRonly). Results: Multivariate analysis revealed higher age (p = 0.003) and HE episodes prior to TIPS (p = 0.004) as risk factors for HE after TIPS. LM has no prophylactic effect. LR prevents HE recurrence at 1, 3 and 12 months after TIPS (p = 0.003, p = 0.003, p = 0.006) but does not prevent HE in patients with no history of HE (p = 0.234, p = 0.483, p = 0.121). LR prevents HE recurrence compared with LM/NM (25.0% vs. 64.7%, p = 0.007) within 12 months after TIPS, whereas de novo occurrence is unaffected (p = 0.098). The additional administration of LOLA to LR has no benefit (LRonly: 25.0%, LR + LOLA: 29.7%, p = 0.780). Conclusions: Higher age and previous HE are risk factors post-TIPS HE. In patients with HE prior to TIPS, effective prophylaxis of HE is feasible via combination of lactulose and rifaximin with no additional benefit from LOLA.

Purpose: To evaluate predictive parameters for the development of Hepatic Encephalopathy (HE) after Transjugular Intrahepatic Portosystemic Shunt (TIPS) placement and for success of shunt modification in the management of shunt-induced HE. Methods: A retrospective analysis of all patients with TIPS (n = 344) has been performed since 2011 in our university liver center. n = 45 patients with HE after TIPS were compared to n = 48 patients without HE after TIPS (case-control-matching). Of n = 45 patients with TIPS-induced HE, n = 20 patients received a reduction stent (n = 18) or TIPS occlusion (n = 2) and were differentiated into responders (improvement by at least one HE grade according to the West Haven classification) and non-responders (no improvement). Results: Older patient age, increased serum creatinine and elevated International Normalized Ratio (INR) immediately after TIPS placement were independent predictors for the development of HE. In 11/20 patients (responders, 55%) undergoing shunt modification, the HE grade was improved compared with nine non-responders (45%), with no relevant recurrence of refractory ascites or variceal bleeding. A high HE grade after TIPS insertion was the only positive predictor of treatment response (p = 0.019). A total of 10/11 responders (91%) survived the 6 months follow-up after modification but only 6/9 non-responders (67%) survived. Discussion: Older patient age as well as an increased serum creatinine and INR after TIPS are potential predictors for the development of HE. TIPS reduction for the treatment of TIPS-induced HE is safe, with particular benefit for patients with pronounced HE.