Assessment of in vivo bone activity patterns in medial mobile-bearing unicompartmental knee arthroplasty

Aims Higher osteoblastic bone activity is expected in aseptic loosening and painful unicompartmental knee arthroplasty (UKA). However, insights into normal bone activity patterns after medial UKAs are lacking. The aim of this study was to identify the evolution in bone activity pattern in well-functioning medial mobile-bearing UKAs. Methods In total, 34 patients (13 female, 21 male; mean age 62 years (41 to 79); BMI 29.7 kg/m2 (23.6 to 42.1)) with 38 medial Oxford partial UKAs (20 left, 18 right; 19 cementless, 14 cemented, and five hybrid) were prospectively followed with sequential 99mTc-hydroxymethane diphosphonate single photon emission CT (SPECT)/CT preoperatively, and at one and two years postoperatively. Changes in mean osteoblastic activity were investigated using a tracer localization scheme with volumes of interest (VOIs), reported by normalized mean tracer values. A SPECT/CT registration platform additionally explored cortical tracer evolution in zones of interest identified by previous experimental research. Results Significant reduction of tracer activity from the preoperative situation was found in femoral and anteromedial tibial VOIs adjacent to the UKA components. Temporarily increased osteoblastic bone activity was observed in VOIs comprising the UKA keel structure at one year postoperatively compared to the preoperative activity. Persistent higher tracer uptake was found in the posterior tibial cortex at final follow-up. Multivariate analysis showed no statistical difference in osteoblastic bone activity underneath cemented or cementless components. Conclusion Well-functioning medial mobile-bearing UKAs showed distinct changes in patterns of normalized bone tracer activity in the different VOIs adjacent to the prosthetic components, regardless of their type of fixation. Compared to the preoperative situation, persistent high bone activity was found underneath the keel and the posterior tibial cortex at final follow-up, with significant reduced activity only being identified in femoral and anteromedial tibial VOIs. Cite this article: Bone Joint J 2022;104-B(1):34–44.

Assessment relation of myocardial detector counts and administered activity of 99mTc-SestaMIBI in MPI: The effects of body weight, BMI and gender

Introduction: In myocardial perfusion imaging, reducing the number of photons in images of obese patients reduces image quality. To solve this problem, we need to inject the tracer activity according to the patients’ weight. This study aimed to investigate the relationship between myocardial detector counts with patients’ weight, BMI, and gender. Materials and Methods: 129 patients underwent myocardial perfusion imaging in a two-day stress-first protocol, but only rest images were included in this study. Multiplication factor (MF=0.13/AVGweight0.64 ) ×body weight(kg)+1-0.13×AVGweight0.36 ) was used to determine the amount of tracer activity to patients. The total of myocardial detector counts in the raw images was calculated from the summation of 32 projections for each patient. Multiple linear regression test was used to simultaneously examine the effects of gender, BMI, and weight on photon counts. To evaluate the effect of breast attenuation, the photon counts of 22 female patients in the Breast Up position were also assessed. Results: There was no significant relationship between photon counts and patients’ weight (p=0.129), and BMI (0.406) but gender had significant effects on photon counts and myocardial detector counts were higher in males (p=0.00). There was a statistically significant difference between the images of Breast Up and non-Breast Up position, and myocardial detector counts were higher in the breast-up imaging method(p=0.00). Conclusion: Using the formula mentioned above, the image quality is similar in obese and lean patients, but myocardial detector counts are higher in males and this formula needs to be adjusted according to the patient’s gender.

Evaluation of 18F-FDG PET/CT images acquired with a reduced scan time duration in lymphoma patients using the digital biograph vision

Background The superior accuracy and sensitivity of 18F-FDG-PET/CT in comparison to morphological imaging alone leads to an upstaging in up to 30% of lymphoma patients. Novel digital PET/CT scanners might enable to reduce administered tracer activity or scan time duration while maintaining diagnostic performance; this might allow for a higher patient throughput or a reduced radiation exposure, respectively. In particular, the radiation exposure reduction is of interest due to the often young age and high remission rate of lymphoma patients. Methods Twenty patients with (suspected) lymphoma (6 for initial staging, 12 after systemic treatment, 2 in suspicion of recurrence) sequentially underwent 18F-FDG-PET/CT examinations on a digital PET/CT (Siemens Biograph Vision) with a total scan time duration of 15 min (reference acquisition protocol) and 5 min (reduced acquisition protocol) using continuous-bed-motion. Both data sets were reconstructed using either standalone time of flight (TOF) or in combination with point spread function (PSF), each with 2 and 4 iterations. Lesion detectability by blinded assessment (separately for supra- and infradiaphragmal nodal lesions and for extranodal lesions), lesion image quantification, and image noise were used as metrics to assess diagnostic performance. Additionally, Deauville Score was compared for all patients after systemic treatment. Results All defined regions were correctly classified in the images acquired with reduced emission time, and therefore, no changes in staging were observed. Lesion quantification was acceptable, that is, mean absolute percentage deviation of maximum and peak standardized uptake values were 6.8 and 6.4% (derived from 30 lesions). A threefold reduction of scan time duration led to an increase in image noise from 7.1 to 11.0% (images reconstructed with 4 iterations) and from 4.7 to 7.2% (images reconstructed with 2 iterations). No deviations in Deauville Score were observed. Conclusion These results suggest that scan time duration or administered tracer activity can be reduced threefold without compromising diagnostic performance. Especially a reduction of administered activity might allow for a lower radiation exposure and better health economics. Larger trials are warranted to confirm our results.

Evaluation of 18F-FDG PET/CT Images Acquired with a Reduced Scan Time Duration in Lymphoma Patients using the Digital Biograph Vision

Background The superior accuracy and sensitivity of 18 F-FDG-PET/CT in comparison to morphological imaging alone leads to an upstaging in up to 30% of lymphoma patients. Novel digital PET/CT scanners might enable to reduce administered tracer activity or scan time duration while maintaining diagnostic performance; this might allow for a higher patient throughput or a reduced radiation exposure, respectively. In particular, the radiation exposure reduction is of interest due to the often young age and high remission rate of lymphoma patients. Methods Twenty patients with (suspected) lymphoma (6 for initial staging, 12 after systemic treatment, 2 in suspicion of recurrence) sequentially underwent 18 F-FDG-PET/CT examinations on a digital PET/CT (Siemens Biograph Vision) with a total scan time duration of 15 minutes (reference acquisition protocol) and 5 minutes (reduced acquisition protocol) using continuous-bed-motion. Both data sets were reconstructed using either standalone time of flight (TOF) or in combination with point spread function (PSF), each with 2 and 4 iterations. Lesion detectability by blinded assessment (separately for supra- and infradiaphragmal nodal lesions and for extranodal lesions), lesion image quantification, and image noise were used as metrics to assess diagnostic performance. Additionally, Deauville Score was compared for all patients after systemic treatment. Results All defined regions were correctly classified in the images acquired with reduced emission time, and therefore, no changes in staging were observed. Lesion quantification was acceptable, that is, mean absolute percentage deviation of maximum and peak standardized uptake values were 6.8% and 6.4% (derived from 30 lesions). A threefold reduction of scan time duration led to an increase in image noise from 7.1% to 11.0% (images reconstructed with 4 iterations) and from 4.7% to 7.2% (images reconstructed with 2 iterations). No deviations in Deauville Score were observed. Conclusion These results suggest that scan time duration or administered tracer activity can be reduced threefold without compromising diagnostic performance. Especially a reduction of administered activity might allow for a lower radiation exposure and better health economics. Larger trials are warranted to confirm our results.

Evaluation of 18F-FDG PET/CT Images Acquired with a Reduced Scan Time Duration in Lymphoma Patients using the Digital Biograph Vision

Background The superior accuracy and sensitivity of 18 F-FDG-PET/CT in comparison to morphological imaging alone leads to an upstaging in up to 30% of lymphoma patients. Novel digital PET/CT scanners might enable to reduce administered tracer activity or scan time duration while maintaining diagnostic performance; this might allow for a higher patient throughput or a reduced radiation exposure, respectively. In particular, the radiation exposure reduction is of interest due to the often young age and high remission rate of lymphoma patients. Methods Twenty patients with (suspected) lymphoma (6 for initial staging, 12 after systemic treatment, 2 in suspicion of recurrence) sequentially underwent 18 F-FDG-PET/CT examinations on a digital PET/CT (Siemens Biograph Vision) with a total scan time duration of 15 minutes (reference acquisition protocol) and 5 minutes (reduced acquisition protocol) using continuous-bed-motion. Both data sets were reconstructed using either standalone time of flight (TOF) or in combination with point spread function (PSF), each with 2 and 4 iterations. Lesion detectability by blinded assessment (separately for supra- and infradiaphragmal nodal lesions and for extranodal lesions), lesion image quantification, and image noise were used as metrics to assess diagnostic performance. Additionally, Deauville Score was compared for all patients after systemic treatment. Results All defined regions were correctly classified in the images acquired with reduced emission time, and therefore, no changes in staging were observed. Lesion quantification was acceptable, that is, mean absolute percentage deviation of maximum and peak standardized uptake values were 6.8% and 6.4% (derived from 30 lesions). A threefold reduction of scan time duration led to an increase in image noise from 7.1% to 11.0% (images reconstructed with 4 iterations) and from 4.7% to 7.2% (images reconstructed with 2 iterations). No deviations in Deauville Score were observed. Conclusion These results suggest that scan time duration or administered tracer activity can be reduced threefold without compromising diagnostic performance. Especially a reduction of administered activity might allow for a lower radiation exposure and better health economics. Larger trials are warranted to confirm our results.

Omphalomesenteric duct resection using an intraumbilical round incision or a transumbilical vertical incision: report of two cases

We report our experience with two patients who underwent omphalomesenteric duct resection: one for a patent omphalomesenteric duct and the other for a Meckel diverticulum connected to the umbilicus by a fibrous cord. We used an intraumbilical round incision and a transumbilical vertical incision, respectively. The first patient was a neonate with a patent omphalomesenteric duct who appeared to have a small stoma after ligature of the umbilical cord. Contrast media, injected through a catheter inserted into the stoma, entered the lumen of the small bowel. The second patient was an infant with a Meckel diverticulum connected to the umbilicus by a fibrous cord. After bloody stool was noted, nuclear imaging using 99m technetium pertechnetate revealed a small, round area of intense tracer activity in the midabdomen, suggesting the presence of ectopic gastric mucosa. Using either an intraumbilical or a transumbilical incision is safe and provides good cosmesis.

Evaluation of 18F-FDG PET/CT Images Acquired with a Reduced Scan Time Duration in Lymphoma Patients using the Digital Biograph Vision

Background: The superior accuracy and sensitivity of 18F-FDG-PET/CT in comparison to morphological imaging alone leads to an upstaging in up to 30 % of lymphoma patients. Novel digital PET/CT scanners might enable to reduce administered tracer activity or scan time duration while maintaining diagnostic performance; this might allow for a higher patient throughput or a reduced radiation exposure, respectively. In particular, the radiation exposure reduction is of interest due to the often young age and high remission rate of lymphoma patients.Methods: Twenty patients with (suspected) lymphoma (6 for initial staging, 12 after systemic treatment, 2 in suspicion of recurrence) sequentially underwent 18F-FDG-PET/CT examinations on a digital PET/CT (Siemens Biograph Vision) with a total scan time duration of 15 minutes (reference acquisition protocol) and 5 minutes (reduced acquisition protocol) using continuous-bed-motion. Both data sets were reconstructed using either standalone time of flight (TOF) or in combination with point spread function (PSF), each with 2 and 4 iterations. Lesion detectability by blinded assessment (separately for supra- and infradiaphragmal nodal lesions and for extranodal lesions), lesion image quantification, and image noise were used as metrics to assess diagnostic performance. Additionally, Deauville Score was compared for all patients after systemic treatment.Results: All defined regions were correctly classified in the images acquired with reduced emission time, and therefore, no changes in staging were observed. Lesion quantification was acceptable, that is, mean absolute percentage deviation of maximum and peak standardized uptake values were 6.8% and 6.4% (derived from 30 lesions). A threefold reduction of scan time duration led to an increase in image noise from 7.1% to 11.0% (images reconstructed with 4 iterations) and from 4.7% to 7.2% (images reconstructed with 2 iterations). No deviations in Deauville Score were observed.Conclusion: These results suggest that scan time duration or administered tracer activity can be reduced threefold without compromising diagnostic performance. Especially a reduction of administered activity might allow for a lower radiation exposure and better health economics. Larger trials are warranted to confirm our results.

Evaluation of 18F-FDG PET/CT Images Acquired with a Reduced Scan Time Duration in Lymphoma Patients using the Digital Biograph Vision

Background: The superior accuracy and sensitivity of 18F-FDG-PET/CT in comparison to morphological imaging alone leads to an upstaging in up to 30 % of lymphoma patients. Novel digital PET/CT scanners might enable to reduce administered tracer activity or scan time duration while maintaining diagnostic performance; this might allow for a higher patient throughput or a reduced radiation exposure, respectively. In particular, the radiation exposure reduction is of interest due to the often young age and high remission rate of lymphoma patients.Methods: Twenty patients with (suspected) lymphoma (6 for initial staging, 12 after systemic treatment, 2 in suspicion of recurrence) sequentially underwent 18F-FDG-PET/CT examinations on a digital PET/CT (Siemens Biograph Vision) with a total scan time duration of 15 minutes (reference acquisition protocol) and 5 minutes (reduced acquisition protocol) using continuous-bed-motion. Both data sets were reconstructed using either standalone time of flight (TOF) or in combination with point spread function (PSF), each with 2 and 4 iterations. Lesion detectability by blinded assessment (separately for supra- and infradiaphragmal nodal lesions and for extranodal lesions), lesion image quantification, and image noise were used as metrics to assess diagnostic performance. Additionally, Deauville Score was compared for all patients after systemic treatment.Results: All defined regions were correctly classified in the images acquired with reduced emission time, and therefore, no changes in staging were observed. Lesion quantification was acceptable, that is, mean absolute percentage deviation of maximum and peak standardized uptake values were 6.8% and 6.4% (derived from 30 lesions). A threefold reduction of scan time duration led to an increase in image noise from 7.1% to 11.0% (images reconstructed with 4 iterations) and from 4.7% to 7.2% (images reconstructed with 2 iterations). No deviations in Deauville Score were observed.Conclusion: These results suggest that scan time duration or administered tracer activity can be reduced threefold without compromising diagnostic performance. Especially a reduction of administered activity might allow for a lower radiation exposure and better health economics. Larger trials are warranted to confirm our results.

Reliable quantification of 18F-GE-180 PET neuroinflammation studies using an individually scaled population-based input function or late tissue-to-blood ratio

Purpose Tracer kinetic modeling of tissue time activity curves and the individual input function based on arterial blood sampling and metabolite correction is the gold standard for quantitative characterization of microglia activation by PET with the translocator protein (TSPO) ligand 18F-GE-180. This study tested simplified methods for quantification of 18F-GE-180 PET. Methods Dynamic 18F-GE-180 PET with arterial blood sampling and metabolite correction was performed in five healthy volunteers and 20 liver-transplanted patients. Population-based input function templates were generated by averaging individual input functions normalized to the total area under the input function using a leave-one-out approach. Individual population-based input functions were obtained by scaling the input function template with the individual parent activity concentration of 18F-GE-180 in arterial plasma in a blood sample drawn at 27.5 min or by the individual administered tracer activity, respectively. The total 18F-GE-180 distribution volume (VT) was estimated in 12 regions-of-interest (ROIs) by the invasive Logan plot using the measured or the population-based input functions. Late ROI-to-whole-blood and ROI-to-cerebellum ratio were also computed. Results Correlation with the reference VT (with individually measured input function) was very high for VT with the population-based input function scaled with the blood sample and for the ROI-to-whole-blood ratio (Pearson correlation coefficient = 0.989 ± 0.006 and 0.970 ± 0.005). The correlation was only moderate for VT with the population-based input function scaled with tracer activity dose and for the ROI-to-cerebellum ratio (0.653 ± 0.074 and 0.384 ± 0.177). Reference VT, population-based VT with scaling by the blood sample, and ROI-to-whole-blood ratio were sensitive to the TSPO gene polymorphism. Population-based VT with scaling to the administered tracer activity and the ROI-to-cerebellum ratio failed to detect a polymorphism effect. Conclusion These results support the use of a population-based input function scaled with a single blood sample or the ROI-to-whole-blood ratio at a late time point for simplified quantitative analysis of 18F-GE-180 PET.

[18F]Fluciclovine-PET/MRI use in monitoring response to androgen deprivation therapy in men with prostate cancer following initial staging.

216 Background: [18F]Fluciclovine PET is clinically approved for detection of biochemically recurrent prostate cancer (PCa). However, its use for initial staging and treatment monitoring remains uncertain. No published data exists evaluating the use of fluciclovine-PET for monitoring response to androgen deprivation therapy. Thus, the purpose of this study is to evaluate the potential use of fluciclovine-PET in monitoring response to androgen deprivation therapy (ADT) during initial treatment of patients with newly diagnosed high risk PCa. Methods: A prospective study enrolled patients with high-risk PCa who had no imaging evidence of metastatic disease. All patients underwent a pretreatment fluciclovine-PET/MRI for primary staging, 6 weeks of ADT, and had a follow-up PET/MRI. All exams were interpreted by 3 nuclear medicine physicians. Identification of the primary intraprostatic lesion and nodal metastatic disease was performed with mean and maximum SUV of the MRI-defined primary prostatic lesions and lymph node metastases measured before and after ADT. Results: A total of 10 patients were enrolled. Gleason scores of their primary tumor were 3+4 (n = 2), 4+3 (n=2), 8 (n = 3), and 9 (n = 3). The average pretreatment serum PSA value was 33.04 ng/mL (range 2.83–76.5). The average serum PSA 6 weeks following initiation of ADT was 2.13 ng/mL (range 0.29–5.66). The primary intraprostatic lesion was accurately identified in all 10 patients and 7/10 patients demonstrated suspicious lymph nodes on the pretreatment PET/MRI. Following ADT, all 10 patients demonstrated a decrease in tracer activity both within the primary intraprostatic lesion and suspicious lymph nodes. The primary lesion mean SUV prior to treatment was 4.46±1.14 and 2.37±1.07 following initiation of ADT (p=0.0007). The primary lesion maximum SUV prior to treatment was 7.13±1.70 and 3.54±2.04 following initiation of ADT (p=0.0006). Conclusions: Fluciclovine-PET tracer activity in patients with PCa undergoing ADT appears to correlate with decrease in serum PSA. Fluciclovine-PET imaging may be useful in monitoring response to ADT, particularly if there is a failure of appropriate PSA response. Clinical trial information: NCT03264456.