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.

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.

Comparison of PSMA-ligand PET/CT and multiparametric MRI for the detection of recurrent prostate cancer in the pelvis.

PURPOSE: So far, there have been very few studies which provide a direct comparison between MRI and PSMA-ligand PET/CT for the detection of recurrent prostate cancer (rPC). This present study therefore aims to provide further clinical data in order to resolve this urgent clinical question, and thereby strengthen clinical recommendations. METHODS: A retrospective analysis was performed for patients who were scanned at our institution with whole-body PSMA-PET/CT (tracer: 68Ga-PSMA-11) between January 2017 and September 2018 in order to detect rPC. Amongst them, 43 underwent an additional pelvic MRI within 2 months. Both modalities were compared as follows: a consensus read of the PET data was performed by two nuclear physicians. All lesions were recorded with respect to their type and localization. The same process was conducted by two radiologists for pelvic MRI. Thereafter, both modalities were directly compared for every patient and lesion. RESULTS: Overall, 30/43 patients (69.8%) presented with a pathologic MRI and 38/43 (88.4%) with a pathologic PSMA-PET/CT of the pelvis. MRI detected 53 pelvic rPC lesions (13 of them classified as "uncertain") and PSMA-PET/CT detected 75 pelvic lesions (three classified as "uncertain"). The superiority of PSMA-PET/CT was statistically significant only if uncertain lesions were classified as false-positive. CONCLUSIONS: PSMA-PET/CT detected more pelvic lesions characteristic for rPC when compared to MRI. In order to detect rPC, a potential future scenario could be conducting first a PSMA-PET/CT. Combining the advantages of both modalities in hybrid PET/MRI scanners would be an ideal future scenario.

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.

Metabolomic tissue signature in human non-alcoholic fatty liver disease identifies protective candidate metabolites.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries, yet its pathophysiology is incompletely understood. Small-molecule metabolite screens may offer new insights into disease mechanisms and reveal new treatment targets. METHODS: Discovery (N = 33) and replication (N = 66) of liver biopsies spanning the range from normal liver histology to non-alcoholic steatohepatitis (NASH) were ascertained ensuring rapid freezing under 30 s in patients. 252 metabolites were assessed using GC/MS. Replicated metabolites were evaluated in a murine high-fat diet model of NAFLD. RESULTS: In a two-stage metabolic screening, hydroquinone (HQ, p(combined) = 3.0 × 10(-4)) and nicotinic acid (NA, p(combined) = 3.9 × 10(-9)) were inversely correlated with histological NAFLD severity. A murine high-fat diet model of NAFLD demonstrated a protective effect of these two substances against NAFLD: Supplementation with 1% HQ reduced only liver steatosis, whereas 0.6% NA reduced both liver fat content and serum transaminase levels and induced a complex regulatory network of genes linked to NALFD pathogenesis in a global expression pathway analysis. Human nutritional intake of NA equivalent was also consistent with a protective effect of NA against NASH progression. CONCLUSION: This first small-molecular screen of human liver tissue identified two replicated protective metabolites. Either the use of NA or targeting its regulatory pathways might be explored to treat or prevent human NAFLD.

Hemorrhagic transformation of ischemic stroke in diabetics on sulfonylureas.

OBJECTIVE: Disability or death occurs more frequently in patients with hemorrhagic transformation (HT) after ischemic stroke. In rat models of stroke, sulfonylurea (SU) drugs such as glibenclamide (adopted US name, glyburide) confer protection against swelling and HT through actions on the novel SUR1-regulated NC(Ca-ATP) channel. Here, we sought to determine whether the use of SU drugs in patients with diabetes mellitus (DM) presenting with acute ischemic stroke might influence the incidence of HT. METHODS: We retrospectively analyzed data on 220 patients with DM who presented with acute ischemic stroke, 43 of whom were managed with and continued to receive SU drugs, and 177 of whom were managed without (controls). RESULTS: During a median length of stay in hospital of 11 days, 20 control patients (11%) experienced symptomatic HT (sHT), whereas no patient in the SU group experienced sHT (p = 0.016). No patient in the SU group died, compared to 18 (10%) in the control group (p = 0.027). Similarly favorable outcomes were observed after matching for baseline imbalances and excluding outliers. In support of the proposed mechanism, we present a case of sHT in which an analysis of brain tissues obtained intraoperatively showed prominent upregulation of SUR1, the target of SU drugs, in microvessels and neurons. INTERPRETATION: We conclude that, in diabetic patients with acute ischemic stroke, prior and continued use of SU drugs is associated with reduced sHT compared to those whose treatment regimen does not include SU drugs.

Prevalence and patterns of anatomical risk factors in patients after patellar dislocation: a case control study using MRI.

OBJECTIVE: To assess anatomical risk factors in patients after lateral patellar dislocation (LPD) and controls using MRI. METHODS: MR images of 186 knees after LPD and of 186 age- and gender-matched controls were analysed. The presence of trochlear dysplasia was assessed by evaluation of trochlear inclination, facet asymmetry, and trochlear depth; patella alta was evaluated by the Insall-Salvati index and Caton-Deschamps index; the lateralised force vector was measured by the tibial tuberosity-trochlear groove (TT-TG) distance. RESULTS: Compared with controls, dislocators had significantly lower values for all three parameters of trochlear dysplasia (-32 %, -32 %, -44 %) and significantly higher values for patella alta (+14 %,+13 %) and TT-TG (+49 %) (all P < 0.001). Trochlear dysplasia was observed in 112 dislocators (66 %), of whom 61 (36 %) additionally had patella alta and 15 (9 %) an abnormal TT-TG. As isolated risk factors, patella alta (15 %) and abnormal TT-TG (1 %) were rare. Only 25 dislocators (15 %) had no anatomical risk factors. Trochlear dysplasia in conjunction with abnormal TT-TG or patella alta is associated with a 37- and 41-fold higher risk. CONCLUSION: Most dislocators have anatomical risk factors, varying in severity and constellation.

Prevalence of cartilage lesions and early osteoarthritis in patients with patellar dislocation.

OBJECTIVES: Assessment of cartilage lesions and osteoarthritis (OA) of the patellofemoral joint in patients following lateral patellar dislocation using magnetic resonance imaging (MRI). METHODS: MR images of 129 knees (mean age 26 years, range 11-56) grouped as acute (A), recurrent (B), and chronic (C) dislocators were analysed regarding the prevalence and severity of patellofemoral cartilage lesions. Grades of OA were assessed using modified WORMS. RESULTS: In groups A, B, and C the prevalence of cartilage lesions was 71%, 82%, and 97%, respectively. Most lesions were located on the central patella in groups A and B (central 69% and 78%; medial 56% and 47%; lateral 31% and 42%), whereas group C revealed all regions affected (73%, 61%, and 67%). Of group A, 14% had mild OA and 64% of group B. Group C showed mild OA in 62% and moderate OA in 18%. Cartilage defect size and prevalence of OA was correlated with number of dislocations (r = 0.41 and r = 0.59; P < 0.001). CONCLUSIONS: Cartilage lesions and early OA are common after patellar dislocation and appear to increase with the frequency of dislocation. Both conditions should be considered when interpreting MRI in such patients, because of implications for treatment. KEY POINTS : • Cartilage lesions are very common after patellar dislocation. • The severity of cartilage lesions increases with number of dislocations. • Osteoarthritis is common after recurrent patellar dislocation, even in young patients. • Detecting cartilage lesions is important after patellar dislocation.

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.

Terminal part of thoracic duct: high-resolution US imaging.

PURPOSE: To assess ultrasonographic (US) examination results of the cervical part of the thoracic duct, to provide standard diameters, and to evaluate the diameter of the cervical thoracic duct in certain diseases suspected to involve an abnormal load of chyle (liver, heart, and inflammatory bowel diseases). MATERIALS AND METHODS: The study was approved by the institutional review committee, and written informed consent was obtained from all subjects. Diameter and variations of the cervical thoracic duct were assessed by using US in 265 healthy volunteers (age range, 21-82 years) from a population-based study, in 196 subjects with documented liver cirrhosis (age range, 19-87 years), in 68 subjects with chronic hepatitis (age range, 17-73 years), in 39 subjects with congestive heart failure (age range, 46-85 years), and in 17 subjects with inflammatory bowel disease (age range, 18-66 years). US examinations were performed with high-resolution linear probes (7-12 MHz). RESULTS: A standard imaging approach guided by anatomic structures was established. Dynamic imaging of the chyle flow and valve function was possible. The thoracic duct was visualized in 564 (96%) of 585 examinations. The average thoracic duct diameter in healthy volunteers was 2.5 mm, which was independent of the subjects' age. The diameter was significantly higher in subjects with congestive heart failure (6.3 mm, P < .0001) and liver cirrhosis (5.6 mm, P < .0001). Anatomic variations were present in 27% of subjects. CONCLUSION: High-resolution US with linear probes allows assessment of the cervical thoracic duct with high detection rates. Recognition of local anatomy, diameter, and chyle flow may aid functional assessment.

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.

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.