Determination of optimal 68 Ga-PSMA PET/CT imaging time in prostate cancers by total-body dynamic PET/CT.

BACKGROUND: 68 Ga-PSMA PET/CT has been widely used in patients with prostate cancer. Due to the limited axial field of view of conventional PET scanners, whole-body dynamic 68 Ga-PSMA PET/CT has not been performed. We investigated the time-activity curves (TACs) of prostate cancer pathological lesions and physiologic bladder activity to determine the optimal 68 Ga-PSMA PET/CT imaging time by total-body (TB) PET/CT. METHODS: Dynamic TB-PET performed on 11 patients with prostate cancer was analyzed. TACs were obtained by drawing regions of interest in normal organs and pathological lesions (primary prostate lesions and lymph nodes and bone metastases). We evaluated the 68 Ga-PSMA uptake pattern of normal organs, urinary bladder, and pathological lesions. RESULTS: The urinary bladder TAC increased slowly between 180 and 330 s post-injection and then rapidly between 5.5 and 60.0 min post-injection. The pathological lesion uptake increased rapidly during the first 5 min post-injection and then slowly through the remaining 55 min. Six minutes post-injection was the optimal time with the highest pathological lesion SUVmean values still higher than the urinary bladder activity value. However, these prostate lesion, lymph node metastasis, and bone metastasis SUVmean values were one-third, one-half, and one-half the corresponding values 60 min post-injection, suggesting that early imaging might miss low PSMA uptake lesions. A minimum of 35 min post-injection was required for the pathological lesions to have SUVmean values similar to the corresponding values at 60 min post-injection (all P > 0.05), even though the pathological lesion SUVmean values showed a continuous upward trend through the 60 min. CONCLUSIONS: Combining early dynamic 68 Ga-PSMA PET (75-360 s) and conventional static imaging 60 min post-injection could avoid the urinary bladder activity interference to better detect pathological lesions and lesions with relatively low PSMA uptake. The pathological lesion SUVmean values at 35-59 min and 60 min post-injection were similar, so 68 Ga-PSMA PET imaging could also be made at 35-59 min post-injection.

Prediction model of early biomarkers of massive cerebral infarction caused by anterior circulation occlusion: Establishment and evaluation.

Objective: The purpose of this study is to establish and evaluate an early biomarker prediction model of massive cerebral infarction caused by anterior circulation occlusion. Methods: One hundred thirty-four patients with acute cerebral infarction from January 2018 to October 2020 were selected to establish the development cohort for the internal test of the nomogram. Ninety-one patients with acute cerebral infarction hospitalized in our hospital from December 2020 to December 2021 were constituted the validation cohort for the external validation. All patients underwent baseline computed tomography (CT) scans within 12 h of onset and early imaging signs (hyperdense middle cerebral artery sign, obscuration of the lentiform nucleus, insular ribbon sign) of acute cerebral infarction were identified on CT by two neurologists. Based on follow-up CT images, patients were then divided into a massive cerebral infarction group and a non-massive cerebral infarction group. The nomogram model was constructed based on logistic regression analysis with R language. The nomogram was subsequently validated in an independent external validation cohort. Accuracy and discrimination of the prediction model were evaluated by a calibration chart, receiver operating characteristic (ROC) curve, and decision curve. Results: The indicators, including insular ribbon sign, reperfusion therapy, National Institutes of Health Stroke Scale (NHISS) score, previous cerebral infarction, and atrial fibrillation, were entered into the prediction model through binary logistic regression analysis. The prediction model showed good predictive ability. The area under the ROC curve of the prediction model was 0.848. The specificity, sensitivity, and Youden index were 0.864, 0.733, and 0.597, respectively. This nomogram to the validation cohort also showed good discrimination (AUC = 0.940, 95% CI 0.894-0.985) and calibration. Conclusion: Demonstrating favorable predictive efficacy and reproducibility, this study successfully established a prediction model of CT imaging signs and clinical data as early biomarkers of massive cerebral infarction caused by anterior circulation occlusion.

Basal Septal Hypertrophy as the Early Imaging Biomarker for Adaptive Phase of Remodeling Prior to Heart Failure.

Hypertension plays a dominant role in the development of left ventricular (LV) remodeling and heart failure, in addition to being the main risk factor for coronary artery disease. In this review, we focus on the focal geometric and functional tissue aspects of the LV septal base, since basal septal hypertrophy (BSH), as the early imaging biomarker of LV remodeling due to hypertensive heart disease, is detected in cross-sectional clinic studies. In addition, the validation of BSH by animal studies using third generation microimaging and relevant clinical observations are also discussed in the report. Finally, an evaluation of both human and animal quantitative imaging studies and the importance of combined cardiac imaging methods and stress-induction in the separation of adaptive and maladaptive phases of the LV remodeling are pointed out. As a result, BSH, as the early imaging biomarker and quantitative follow-up of functional analysis in hypertension, could possibly contribute to early treatment in a timely fashion in the prevention of hypertensive disease progression to heart failure. A variety of stress stimuli in etiopathogenesis and the difficulty of diagnosing pure hemodynamic overload mediated BSH lead to an absence of the certain prevalence of this particular finding in the population.

Comparison of Early Imaging and Imaging 60 min Post-Injection after Forced Diuresis with Furosemide in the Assessment of Local Recurrence in Prostate Cancer Patients with Biochemical Recurrence Referred for 68Ga-PSMA-11 PET/CT.

BACKGROUND: 68Ga-PSMA-11 PET/CT is a promising method for the assessment of local recurrence (LR) in prostate cancer (PCa) patients. The aim of this study was to evaluate the diagnostic performance of early 68Ga-PSMA-11 PET imaging in comparison to 68Ga-PSMA-11 PET imaging 60 min post-injection (p.i.) in the detection of LR in patients with biochemical recurrence (BR) of prostate carcinoma. MATERIALS AND METHODS: 190 image sets of patients with BR in PCa who underwent 68Ga-PSMA-11 PET/CT were assessed retrospectively (median prostate specific antigen (PSA) value, 0.70 ng/mL (range, 0.1-105.6 ng/mL)). Patients received an early static scan of the pelvic area (median, 248 s p.i. (range, 56-923 s)) and a whole-body scan 60 min p.i. (median, 64 min p.i. (range, 45-100 min)) with intravenous administration of 20 mg furosemide i.v. at the time of tracer application, followed by intravenous hydration with 500 mL of sodium chloride (NaCl 0.9%). Assessment was based on visual analysis and calculation of the maximum standardized uptake value (SUVmax) of the pathologic lesions present in the prostate fossa found in the early PET imaging and 60 min PET scans. The scans were characterized as negative, positive, or equivocal. The results were compared, and the combination of early and 60 min p.i. imaging was evaluated. RESULTS: Image assessment resulted in 30 (15.8%) positive, 17 (8.9%) equivocal, and 143 (75.3%) negative findings in early scans, and 28 (14.7%) positive, 25 (13.2%) equivocal, and 137 (72.1%) negative findings of LR in 60 min p.i. images. For combined image analysis, 33 (17.4%) cases were positive and 20 (10.5%) were equivocal. There was no statistical significance between the number of positive (p = 0.815), negative (p = 0.327), and equivocal (p = 0.152) findings. Furthermore, the combination of both scans showed no statistically significant differences for the positive and negative findings (p = 0.063). The median SUVmax was 4.9 (range, 2.0-55.2) for positive lesions in the early scans and 8.0 (range, 2.1-139.9) in the scans 60 min p.i. The median SUVmax for bladder activity was 2.5 (range, 0.9-12.2) in the early scans and 8.2 (range, 1.8-27.6) in the scans 60 min p.i. CONCLUSION: Early static imaging additional to 68Ga-PSMA-11 PET images acquired 60 min p.i. has limited value in patients prepared with furosemide and hydration, and showed no statistically significant change in the detection rate (DR) of LR and the number of equivocal findings. Based on our results, in departments following a protocol with forced diuresis, including furosemide, additional early static imaging cannot be routinely recommended for the assessment of BR in PCa patients.

Removal of Non-economic Damage Caps Is Not Associated with Reductions in Early Imaging for Low Back Pain.

BACKGROUND: Supporters of medical liability reform contend that caps on non-economic damages will decrease defensive medicine. QUESTIONS/PURPOSES: We examined whether removal of caps on non-economic damages affect one type of defensive medical practice, early imaging for new-onset low back pain. PATIENTS AND METHODS: Using administrative claims data, we retrospectively studied adult patients evaluated for new-onset low back pain from 2007 to 2012. We included patients from two states that had caps on non-economic damages struck down in 2010 (n = 462,604) and patients from adjacent states (n = 781,963). Using a difference-in-differences approach, we evaluated the impact of non-economic damage caps on early imaging while adjusting for physician specialty, patient characteristics, and year- and state-level fixed effects. RESULTS: There was no association between non-economic damage caps and early imaging for low back pain among all providers. Removal of a non-economic damage cap was also not associated with a significant change in early imaging within the two cap-removal states. Subgroup analysis by physician specialty demonstrated significantly increased use of early imaging for low back pain by orthopedic or neurological surgeons in the first 12 months following cap removal in one state (but this difference did not persist beyond 12 months). In the other cap-removal state, early imaging increased among orthopedic and neurological surgeons more than 12 months after cap removal. CONCLUSION: We found no association between caps on non-economic damages and early imaging for low back pain among all physicians. However, our subgroup analysis suggests that physician specialties may respond to non-economic damage cap policies differently.

Contribution of 5th minute and 2nd hour images to standard imaging in (68Ga)PSMA 11 PET/CT.

OBJECTIVE: To investigate the superiority or contribution of 5th minute pelvic and 2nd hour whole body Gallium68-prostate-specific membrane antigen-HBED-CC [(68Ga)PSMA 11] Positron Emission Tomography/Computed Tomography (PET/CT) images to 1st hour imaging in patients with prostate cancer (PCa). MATERIALS AND METHODS: A total of 63 patients diagnosed with PCa who underwent (68Ga)PSMA 11 PET/CT between April 2019 and June 2019 and who had 5th minute and 1st and 2nd hour images were included in the study. Early (5th minute) pelvic region and 1st and 2nd hour full body images were obtained from all patients. The regions of interest (ROI) were drawn from the background tissues and the physiological uptake sites in a way to include the same lesions from primary and metastatic lesions in all three imagings, and SUVmax values, and tumor-background ratio (TBR) were calculated. RESULTS: The mean age of the patients was 69.81 ± 8.78 (min/max: 51/91) years. In the 5th minute images, prostate gland and bed were easier to evaluate, because of low bladder activity. However, lymph node evaluation was more difficult due to high vascular activity. In the prostate gland, lymph nodes and bone metastases, both SUVmax values and TBR rates increased with time from the 5th minute (p < 0.001). At the 2nd hour, some lesions became more visible, while decreased activity was observed in some lesions. However, none of the patients required a change in the stage or treatment. CONCLUSION: In conclusion, the 5th minute pelvic images in (68Ga)PSMA 11 PET/CT were helpful in visual evaluation of the prostate gland and bed, while 2nd hour images showed high SUVmax and TBR rates in malignant lesions. As the SUVmax values of benign lesions were found to be lower in the 2nd hour, when compared to the 1st hour, it was thought that the 2nd hour imaging could be used in the additional imaging for suspicious lesions without the need for very long waiting times.

Evolution of ventricular hypertrophy and myocardial mechanics in physiological and pathological hypertrophy.

Left ventricular hypertrophy (LVH) is an adaptive response to physiological or pathological stimuli, and distinguishing between the two has obvious clinical implications. However, asymmetric septal hypertrophy and preserved cardiac function are noted in early stages in both cases. We characterized the early anatomic and functional changes in a mouse model of physiological and pathological stress using serial echocardiography-based morphometry and tissue velocity imaging. Weight-matched CF-1 male mice were separated into Controls ( n = 10), treadmill Exercise 1 h daily for 5 days/wk ( n = 7), and transverse aortic constriction (TAC, n = 7). Hypertrophy was noted first in the left ventricle basal septum compared with other segments in Exercise (0.84 ± 0.02 vs. 0.79 ± 0.03 mm, P = 0.03) and TAC (0.86 ± 0.05 vs. 0.77 ± 0.04 mm, P = 0.02) at 4 and 3 wk, respectively. At 8 wk, eccentric LVH was noted in Exercise and concentric LVH in TAC. Septal E/E' ratio increased in TAC (32.6 ± 3.7 vs. 37 ± 6.2, P = 0.002) compared with the Controls and Exercise (32.3 ± 5.2 vs. 32.8 ± 3.8 and 31.2 ± 4.9 vs. 28.2 ± 5.0, respectively, nonsignificant for both). Septal s' decreased in TAC (21 ± 3.6 vs. 17 ± 4.2 mm/s, P = 0.04) but increased in Exercise (19.6 ± 4.1 vs. 29.2 ± 2.3 mm/s, P = 0.001) and was unchanged in Controls (20.1 ± 4.2 vs. 20.9 ± 5.1 mm/s, nonsignificant). With similar asymmetric septal hypertrophy and normal global function during the first 4-8 wk of pathological and physiological stress, there is an early marginal increase with subsequent decrease in systolic tissue velocity in pathological but early and progressive increase in physiological hypertrophy. Tissue velocities may help adjudicate between these two states when there are no overt anatomic or functional differences. NEW & NOTEWORTHY Pathological and physiological stress-induced ventricular hypertrophy have different clinical connotations but present with asymmetric septal hypertrophy and normal global function in their early stages. We observed a marginal but statistically significant decrease in systolic tissue velocity in pathological but progressive increase in velocity in physiological hypertrophy. Tissue velocity imaging could be an important tool in the management of asymmetric septal hypertrophy by adjudicating between these two etiologies when there are no overt anatomic or functional differences.

Early imaging of a macular hole following vitrectomy with primary silicone oil tamponade.

BACKGROUND: To describe the morphology of a macular hole in the early postoperative period following vitrectomy with primary silicone oil tamponade. METHODS: A case report with optical coherence tomography (OCT) scans prior to surgery, at 20 minutes postoperatively and then at 17 hours postoperatively. RESULTS: OCT images of a 73-year-old woman with a stage 3 macular hole were obtained. At 20 minutes postoperatively, there was a reduction in intraretinal cysts and a reduction in macular hole size with elevated-open configuration. At 17 hours postoperatively, complete macular hole closure was noted. CONCLUSION: OCT Images of a macular hole in the early postoperative period have been successfully obtained. Macular holes can close within 24 hours postoperatively and show morphological changes that may be predictive of closure within 20 minutes postoperatively.