Assessment of malignancy and PSMA expression of uncertain bone foci in [18F]PSMA-1007 PET/CT for prostate cancer-a single-centre experience of PET-guided biopsies.

PURPOSE Uncertain focal bone uptake (UBU) with intensive radiopharmaceutical avidity are frequently observed in patients undergoing [18F]PSMA-1007 PET/CT for the detection of prostate cancer (PC). Such foci can pose diagnostic conundrums and risk incorrect staging. The aim of this short communication is to share the results of PET-guided biopsies of such foci. METHODS A retrospective analysis revealed 10 patients who were referred to our department for PET-guided biopsy of UBU visible in a previous [18F]PSMA-1007 PET/CT. [18F]-PSMA-1007 PET-guided biopsy was conducted for 11 PSMA-avid bone foci in these 10 patients. The biopsy materials were analysed for tissue typing, and immunohistochemistry (IHC) was performed for prostate-specific-membrane-antigen (PSMA) expression. The scans were analysed by two experienced physicians in a consensus read for clinical characteristics and radiopharmaceutical uptake of foci. RESULTS One out of 11 (9.1%) of the foci biopsied was confirmed as bone metastasis of PC with intense PSMA-expression, while 10/11 (90.9%) foci were revealed to be unremarkable bone tissue without evidence of PSMA expression at IHC. Amongst all bone foci assessed by biopsy, eight were visually classified as being at high risk of malignancy in the PET/CT (SUVmean 12.0 ± 8.1; SUVmax 18.8 ± 13.1), three as equivocal (SUVmean 4.6 ± 2.1; SUVmax 7.2 ± 3.0) and zero as low risk. No UBU had any CT correlate. CONCLUSIONS This cohort biopsy revealed that a small but relevant number of UBU are true metastases. For those confirmed as benign, no PSMA expression at IHC was observed, suggesting a non-PSMA mediated cause for intensive [18F]PSMA-1007 uptake of which the reason remains unclear. Readers must interpret such foci with caution in order to reduce the risk of erroneous staging and subsequent treatment. PET-guided biopsy, particularly in the absence of morphological changes in the CT, can be a useful method to clarify such foci

Phenotypic and moleculargenetic investigations on poliovirus serotype 1-isolates from a poliovirus long-term excretor

Ein biologisches Prinzip bei der Poliomyelitis-Eradikation war, dass keine chronischen Poliovirusinfektionen vorkommen. Seit der Einführung der oralen Poliovakzine (OPV) wurden jedoch wenige Fälle von verlängertem Ausscheiden von Vakzin-abgeleiteten Polioviren (VDPV) beobachtet. Ziel der Arbeit war es, zwei Isolate eines in Deutschland lebenden, immundefizienten Poliovirus-Daueraus- scheiders mit Fokus auf die Poliovirusvariabilität phänotypisch und genotypisch zu untersuchen. Der Patient entwickelte im Jahr 2000 eine paralytische Poliomyelitis (letzte OPV-Gabe 1998) und scheidet seit dem Poliovirus Serotyp 1 aus. Die Untersuchungen der Isolate (aus den Jahren 2000 und 2004) basierten auf üblichen Methoden zur intratypischen Differenzierung sowie auf Totalsequenzen, die nach molekularer Klonierung von Teilamplifikaten ermittelt wurden. Es konnte gezeigt werden, dass beide Isolate auf phänotypischer Ebene (ELISA, rct-Marker) „Non-Sabin-like“, genotypisch (Diagnostik-PCR) dagegen „Sabin-like“ reagierten. Die molekulare Feincharakterisierung ließ eine Einordnung beider Isolate als VDPV zu, welche durch die phylogenetische Analyse der Region VP1-2A bestätigt wurde. Die weitere Sequenzanalyse ergab eine hohe genetische Variabilität in Bezug auf die Sabin Typ 1-Sequenz sowie eine im Verlauf der Infektion gestiegene Mikroheterogenität. Dabei zeigte sich, dass die Nukleotid(NS)- und Aminosäuren (AS)-Substitutionsraten in Teilbereichen des Genoms variierten: die höchsten Raten wurden in dem Abschnitt VP2-2B ermittelt, die Regionen VP4 und 3A-3C waren insbesondere auf AS-Ebene stark konserviert. Der hohe Anteil an synonymen NS- und konservativen AS-Mutationen wies darauf hin, dass die Variabilität v.a. durch neutrale Mutationen getragen wurde. Die putativen Motive der Proteasen und Polymerase, sowie RNA-Sekundärstrukturformationen waren hochgradig konserviert. Hinweise auf positive Selektionen von Mutationen ergaben sich an Positionen, die mit der Attenuierung assoziiert sind und bei beiden Isolaten die Wildtyp-spezifische Besetzung aufwiesen, sowie im Bereich der neutralisierenden, antigenen Determinanten bzw. an Positionen, die mit dem zellulären Poliovirus-Rezeptor interagieren.One of the biological principles of the poliomyelitis eradication initiative was, that there were no chronic poliovirus infections. However, since the introduction of the oral poliovaccine (OPV) by Albert Sabin some few cases of prolonged excretion of vaccine-derived polioviruses (VDPV) were observed. The aim of this work was to investigate two sequential isolates of a german poliovirus long-term excretor with focus on the variability in their phenotypic and genomic properties. The patient developed a paralytic poliomyelitis in the year 2000 (the last OPV administration was 1998) and is still excreting poliovirus serotype 1. The investigation of the isolates (from the year 2000 and 2004) based on common methods for intratypic differentiation of poliovirus isolates and on complete genomic sequences, which were determined after molecular cloning of partial amplificates. Both isolates showed “non-sabin-like” characteristics on phenotypic level (ELISA, rct-test) but were characterized as “sabin-like” on genomic level (diagnostic PCR). Further molecular characterization of both isolates led to the classification of VDPVs, which was confirmed by phylogenetic analysis in the genome-region VP1-2A. Sequence analysis revealed a high genomic variability and an increasing microheterogeneity during the course of infection. Nucleotide(NS)- and aminoacid(AS)-substitutions varied over different parts of the genome: the highest substitution rates were observed in the region VP2-2B, where as the regions VP4 and 3A-3C - especially on AS-level – showed to be highly conserved. The high proportion of synonymous NS- and conserved AS- substitutions pointed out, that the sequence variability was mostly sustained by neutral mutations. Putative motifs of the viral proteases and the polymerase and also RNA-regions with an high proportion of secondary structure formation were highly conserved. However, evidence for positive selection of mutations were detected at positions, which were associated with attenuation of neurovirulence and which showed in both isolates reversions to the wildtype sequence, in the region of the neutralizing antigenic sites as well as at positions, which interact with the cellular poliovirus receptor

Impact of pretreatment second look 18FDG-PET/CT on stage and treatment changes in head and neck cancer.

Background Patients diagnosed with locoregionally advanced head and neck squamous cell carcinoma (LAHNSCC) regularly undergo staging with 18F-FDG PET/CT in our center. In cases of delays in radiotherapy (RT) planning CT more than 4 weeks after initial PET/CT or clinically suspected progress, PET/CT is repeated for restaging and as an RT planning reference. Our aim was to determine the impact of second-look PET/CT on stage migration, treatment change and RT planning. Methods Consequent treatment changes were categorized as minor and major. Minor changes were defined as PET/CT-based modifications of RT plans, e.g., the addition of anatomical compartments, changes in high- and low-risk dose levels or both. Major changes included changes from curative to palliative treatment intent and alterations of interdisciplinary treatment plans, such as the addition of induction chemotherapy, switch to primary surgery, no treatment and/or the necessity of additional diagnostic work-up resulting in the postponement or cancellation of treatment. Results Thirty-two newly diagnosed LAHNSCC patients who were treated between 2014 and 2018 underwent second-look PET/CT (median interval 42.5 days). Second-look PET/CT led to locoregional and distant upstaging in 3/32 and 1/32 patients, respectively. In 1/32 patients (3%), second-look PET/CT led to a palliative approach with systemic treatment. New lymph node metastases were discovered in 16 patients, 6 of whom also showed significant progression of the primary tumor, resulting in minor changes in 16 of the remaining 31 patients (52%) who were treated curatively. Conclusion If RT treatment planning of LAHNSCC was delayed by more than 4 weeks after initial PET/CT staging or when progression was clinically suspected, a second look at 18FDG-PET/CT was performed. This led to changes in treatment planning in more than half of the cases, which is expected to directly influence oncologic outcomes

Comparative evaluation of SPECT/CT and CBCT in patients with mandibular osteomyelitis and osteonecrosis

OBJECTIVES: Therapy of osteomyelitis and osteonecrosis very often requires surgery. Proper preoperative radiological evaluation of a lesion's localization and extent is a key in planning surgical bone resection. This study aims to assess the differences between single-photon emission computed tomography and cone beam computed tomography when detecting an osteomyelitis/osteonecrosis lesion as well as the lesion's qualitative parameters, extent, and localization. MATERIAL AND METHODS: Identification of candidates was performed retrospectively following a search for patients with histologically or clinically confirmed osteomyelitis or osteonecrosis. They were matched with a list of patients whose disease extent and localization had been evaluated using single-photon emission computed tomography and cone beam computed tomography in the context of clinical investigations. Subsequently, two experienced examiners for each imaging technique separately performed de novo readings. Detection rate, localization, extent, and qualitative parameters of a lesion were then compared. RESULTS: Twenty-one patients with mandibular osteomyelitis and osteonecrotic lesions were included. Cone beam computed tomography detected more lesions than single-photon emission computed tomography (25 vs. 23; 100% vs. 92%). Cone beam computed tomography showed significantly greater depth, area, and volume, whereas length and width did not differ statistically between the two groups. CONCLUSION: Both single-photon emission computed tomography and cone beam computed tomography could sensitively detect osteomyelitis/osteonecrosis lesions. Only single-photon emission computed tomography showed metabolic changes, whereas cone beam computed tomography seemed to display anatomic morphological reactions more accurately. The selection of the most adequate three-dimensional imaging and the correct interpretation of preoperative imaging remains challenging for clinicians. CLINICAL RELEVANCE: In daily clinical practice, three-dimensional imaging is an important tool for evaluation of osteomyelitis/osteonecrosis lesions. In this context, clinicians should be aware of differences between single-photon emission computed tomography and cone beam computed tomography when detecting and assessing an osteomyelitis/osteonecrosis lesion, especially if a surgical bone resection is planned

Magnetic resonance imaging analysis of rotational alignment in patients with patellar dislocations

Background: the role of anatomic risk factors in patellofemoral instability is not yet fully understood, as they have been observed in patients either alone or in combination and in different degrees of severity.Purpose: to prospectively analyze rotational limb alignment in patients with patellofemoral instability and in controls using magnetic resonance imaging (MRI).Study design: cross-sectional study; Level of evidence, 3.Methods: thirty patients (mean age, 22.9 y; range, 12-41 y) with a history of patellar dislocation and 30 age- and sex-matched controls (mean age, 25.2 y; range, 16-37 y) were investigated. The patients underwent MRI of the leg at 1.5 T using a peripheral angiography coil and a T2-weighted half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence for measuring femoral antetorsion, tibial torsion, knee rotation, and mechanical axis deviation (MAD). The mean values of these parameters were compared between patients and controls. In addition, the patients underwent an assessment to determine the influence of rotational limb alignment on lateral trochlear inclination, trochlear facet asymmetry, trochlear depth, Insall-Salvati index, and tibial tuberosity–trochlear groove distance.Results: patients had 1.56-fold higher mean femoral antetorsion (20.3° ± 10.4° vs 13.0° ± 8.4°; P < .01) and 1.6-fold higher knee rotation (9.4° ± 5.0° vs 5.7° ± 4.3°; P < .01) compared with controls. Moreover, patients had 2.9 times higher MAD (0.81 ± 0.75 mm vs ?0.28 ± 0.87 mm; P < .01). Differences in tibial torsion were not significant. Also, there were no significant correlations between parameters of rotational alignment and standard anatomic risk factors.Conclusion: our results suggest that some patients with nontraumatic patellar instability have greater internal femoral rotation, greater knee rotation, and a tendency for genu valgum compared with healthy controls. Rotational malalignment may be a primary risk factor in patellar dislocation that has so far been underestimated

Process mapping of PTA and stent placement in a university hospital interventional radiology department

Abstract Objective To apply the process mapping technique in an interdisciplinary approach in order to visualize, better understand, and efficiently organize percutaneous transluminal angioplasty (PTA) and stent placement procedures in a university hospital’s interventional radiology department. Methods After providing an overview of seven established mapping techniques for medical professionals, the process mapping technique was chosen and applied in an interdisciplinary approach including referrers (physicians, nurses, and other staff in referring departments, e.g., vascular surgery), providers (interventional radiologists, nurses, technicians, and staff of the angiography suite), and specialists of the hospital’s controlling department. Results A generally binding and standardized process map was created, describing the entire procedure for a patient in whom the radiological intervention of PTA or stent treatment is contemplated from admission to the department of vascular surgery until discharge after successful treatment. This visualization tool assists in better understanding (especially given natural staff fluctuation over time) and efficiently organizing PTA and stent procedures. Conclusion Process mapping can be applied for streamlining workflow in healthcare, especially in interdisciplinary settings. By defining exactly what a business entity does, who is responsible, to what standard a process should be completed, and how the success can be assessed, this technique can be used to eliminate waste and inefficiencies from the workplace while providing high-quality goods and services easily, quickly, and inexpensively. Main Messages • Process mapping can be used in a university hospital’s interventional radiology department. • Process mapping can describe the patient’s entire process from admission to PTA/stent placement until discharge. • Process mapping can be used in interdisciplinary teams (e.g., referrers, providers, and controlling specialists). • Process mapping can be used in order to more efficiently organize PTA and stent placement procedures. • Process mapping can assist in better understanding and efficiently organizing procedures in standardized fashion

Clinical performance of long axial field of view PET/CT: a head-to-head intra-individual comparison of the Biograph Vision Quadra with the Biograph Vision PET/CT.

PURPOSE To investigate the performance of the new long axial field-of-view (LAFOV) Biograph Vision Quadra PET/CT and a standard axial field-of-view (SAFOV) Biograph Vision 600 PET/CT (both: Siemens Healthineers) system using an intra-patient comparison. METHODS Forty-four patients undergoing routine oncological PET/CT were prospectively included and underwent a same-day dual-scanning protocol following a single administration of either 18F-FDG (n = 20), 18F-PSMA-1007 (n = 16) or 68Ga-DOTA-TOC (n = 8). Half the patients first received a clinically routine examination on the SAFOV (FOVaxial 26.3 cm) in continuous bed motion and then immediately afterwards on the LAFOV system (10-min acquisition in list mode, FOVaxial 106 cm); the second half underwent scanning in the reverse order. Comparisons between the LAFOV at different emulated scan times (by rebinning list mode data) and the SAFOV were made for target lesion integral activity, signal to noise (SNR), target lesion to background ratio (TBR) and visual image quality. RESULTS Equivalent target lesion integral activity to the SAFOV acquisitions (16-min duration for a 106 cm FOV) were obtained on the LAFOV in 1.63 ± 0.19 min (mean ± standard error). Equivalent SNR was obtained by 1.82 ± 1.00 min LAFOV acquisitions. No statistically significant differences (p > 0.05) in TBR were observed even for 0.5 min LAFOV examinations. Subjective image quality rated by two physicians confirmed the 10 min LAFOV to be of the highest quality, with equivalence between the LAFOV and the SAFOV at 1.8 ± 0.85 min. By analogy, if the LAFOV scans were maintained at 10 min, proportional reductions in applied radiopharmaceutical could obtain equivalent lesion integral activity for activities under 40 MBq and equivalent doses for the PET component of <1 mSv. CONCLUSION Improved image quality, lesion quantification and SNR resulting from higher sensitivity were demonstrated for an LAFOV system in a head-to-head comparison under clinical conditions. The LAFOV system could deliver images of comparable quality and lesion quantification in under 2 min, compared to routine SAFOV acquisition (16 min for equivalent FOV coverage). Alternatively, the LAFOV system could allow for low-dose examination protocols. Shorter LAFOV acquisitions (0.5 min), while of lower visual quality and SNR, were of adequate quality with respect to target lesion identification, suggesting that ultra-fast or low-dose acquisitions can be acceptable in selected settings

Deep neural network for automatic characterization of lesions on 68Ga-PSMA-11 PET/CT

PURPOSE: This study proposes an automated prostate cancer (PC) lesion characterization method based on the deep neural network to determine tumor burden on 68Ga-PSMA-11 PET/CT to potentially facilitate the optimization of PSMA-directed radionuclide therapy. METHODS: We collected 68Ga-PSMA-11 PET/CT images from 193 patients with metastatic PC at three medical centers. For proof-of-concept, we focused on the detection of pelvis bone and lymph node lesions. A deep neural network (triple-combining 2.5D U-Net) was developed for the automated characterization of these lesions. The proposed method simultaneously extracts features from axial, coronal, and sagittal planes, which mimics the workflow of physicians and reduces computational and memory requirements. RESULTS: Among all the labeled lesions, the network achieved 99% precision, 99% recall, and an F1 score of 99% on bone lesion detection and 94%, precision 89% recall, and an F1 score of 92% on lymph node lesion detection. The segmentation accuracy is lower than the detection. The performance of the network was correlated with the amount of training data. CONCLUSION: We developed a deep neural network to characterize automatically the PC lesions on 68Ga-PSMA-11 PET/CT. The preliminary test within the pelvic area confirms the potential of deep learning methods. Increasing the amount of training data should further enhance the performance of the proposed method and may ultimately allow whole-body assessments