Introduction:¹⁸F-PSMA-1007 PET is used in the management of patients with prostate cancer. However, recent reports indicate a high rate of non-specific bone uptake (NSBU) with ¹⁸F-PSMA-1007, which may lead to false positive diagnosis. NSBU have not been evaluated thoroughly. Here, we evaluate the frequency of NSBU and bone metastases separately for ¹⁸F-PSMA-1007 and ⁶⁸Ga-PSMA-11 in biochemical recurrence (interindividual comparison). Additionally, we investigate NSBU seen in ¹⁸F-PSMA-1007 through follow up examinations (intraindividual comparison) using ⁶⁸Ga-PSMA-11 PET, bone scintigraphy and MRI. Methods: First, all patients (n = 383) who had ⁶⁸Ga-PSMA-11 PET between January 2020 and December 2020 and all patients (n = 409) who had ¹⁸F-PSMA-1007 PET between January 2020 and November 2021 due to biochemical recurrence were included for an interindividual comparison of bone metastases and NSBU rate. In a second approach, we regarded all patients with NSBU in ¹⁸F-PSMA-1007, characterized by focal bone uptake with SUV_max>4 and PSA≤5 ng/ml, who had an additional ⁶⁸Ga-PSMA-11 PET (n = 17) (interindividual comparison). Of these, 12 patients also had bone scintigraphy and wbMRI within a 1–5-week interval. Bone uptake seen on ¹⁸F-PSMA-1007 but not on any of the other four modalities (CT, MRI (n = 1), bone scan and ⁶⁸Ga-PSMA-11 PET) was recorded as false positive. Results: Patients scanned with ¹⁸F-PSMA-1007 PET had a significantly higher rate of NSBU compared with ⁶⁸Ga-PSMA-11 (140 vs. 64; p<0.001); however, the rate of bone metastases was not significantly different (72 vs. 64; P = 0.7). In the intraindividual comparison group, workup by CT, MRI, bone scan and ⁶⁸Ga-PSMA-11 PET resulted in a positive predictive value for ¹⁸F-PSMA-1007 focal bone uptake (mean SUV_max 6.1±2.9) per patient and per lesion of 8.3 % and 3.6 %, respectively. Conclusion: In patients with PSA≤5 ng/mL and SUV>4 at biochemical recurrence, most ¹⁸F-PSMA-1007 focal bone uptake are likely to be false positive and therefore due to NSBU. In case of low clinical likelihood of metastatic disease, ¹⁸F-PSMA-1007 bone uptake without morphologic surrogate should be assessed carefully with regard to localization and clinical context. However, the rate of bone metastases was not higher with ¹⁸F-PSMA-1007 in the clinical routine, indicating that experienced reporting physicians adjust for NSBU findings.

Three imaging modalities are available for the diagnosis of acute appendicitis: ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Transabdominal ultrasound should be the first-line imaging test. Abdominal CT is superior to US and is required immediately in patients with atypical clinical presentation of appendicitis and suspected perforation. However, low-dose unenhanced CT is equal to standard-dose CT with intravenous contrast agents in the detection of five signs of acute appendicitis (thickened appendiceal wall more than 2 mm, cross-sectional diameter greater than 6 mm, periappendicitis, abscess, and appendicolith). MRI is necessary in pregnant women and young adults. This review illustrates the principles of state-of-the-art imaging techniques and their clinical relevance. Key Points: • US is the basic diagnostic method in case of suspected appendicitis. • CT is necessary in patients with atypical presentation of appendicitis. • MRI should be the first-line imaging test in pregnant women. Citation Format: • Karul M, Berliner C, Keller S et al. Imaging of Appendicitis in Adults. Fortschr Röntgenstr 2014; 186: 551 – 558 Zur Akutdiagnostik der Appendizitis stehen drei radiologische Verfahren zur Verfügung: 1. Ultraschall (US); 2. Computertomografie (CT); 3. Magnetresonanztomografie (MRT). Während der transabdominelle Ultraschall zur Basisdiagnostik zählt, sollte die diagnostisch überlegene CT bei atypischen klinischen Appendizitiszeichen und Perforationsverdacht unverzüglich erfolgen. Besonders hervorzuheben ist die native Niedrigdosis-CT, die der Standarddosis-CT nach intravenöser Kontrastmittelapplikation in der Detektion von fünf Appendizitiszeichen (Wandverdickung größer 2 mm, vergrößerter Appendixdurchmesser mehr als 6 mm, Periappendizitis, Abszessformation und Appendicolith) ebenbürtig ist. Die MRT kommt bei Schwangeren und jungen Erwachsenen zum Einsatz. Diese Übersichtsarbeit stellt die Prinzipien der modernen Untersuchungstechniken sowie ihre klinischen Implikationen dar.

The ecosystem of brain tumors is considered immunosuppressed, but our current knowledge may be incomplete. Here we analyzed clinical cell and tissue specimens derived from patients presenting with glioblastoma or nonmalignant intracranial disease to report that the cranial bone (CB) marrow, in juxtaposition to treatment-naive glioblastoma tumors, harbors active lymphoid populations at the time of initial diagnosis. Clinical and anatomical imaging, single-cell molecular and immune cell profiling and quantification of tumor reactivity identified CD8⁺ T cell clonotypes in the CB that were also found in the tumor. These were characterized by acute and durable antitumor response rooted in the entire T cell developmental spectrum. In contrast to distal bone marrow, the CB niche proximal to the tumor showed increased frequencies of tumor-reactive CD8⁺ effector types expressing the lymphoid egress marker S1PR1. In line with this, cranial enhancement of CXCR4 radiolabel may serve as a surrogate marker indicating focal association with improved progression-free survival. The data of this study advocate preservation and further exploitation of these cranioencephalic units for the clinical care of glioblastoma.

With the rapid expansion of robot-assisted surgical procedures, the need for robot-compliant image guidance technologies has also increased. Examples hereof are the integrated firefly fluorescence camera, the drop-in ultrasound probe, and the recently introduced DROP-IN gamma probe. Combined with ⁶⁸Ga–prostate-specific membrane antigen–(PSMA)–11 PET/CT (staging) and ^99mTc-PSMA-I&S SPECT/CT (preoperative imaging), the latter DROP-IN gamma probe technology recently allowed us to perform the first clinical cases of robot-assisted PSMA-guided salvage surgery of lymphatic metastases.