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BACKGROUND: Prostate-specific membrane antigen (PSMA) can provide a prostate cancer (PCa) detection approach in positron emission tomography (PET) using Food and Drug Administration (FDA)-approved PSMA-11 peptide. There are some studies evaluated magnetic-nanoprobes for PSMA detection by MRI, using non-FDA-approved ligands including antibodies or peptides, which are not as specific as PSMA-11. PURPOSE: To assess targeted iron oxide nanoparticles (IONPs) by PSMA-11 peptides as a potential specific nano-molecular probes to investigate a PSMA+ PCa-xenograft model by MRI. STUDY TYPE: Prospective. ANIMAL MODEL: Twenty male C57BL6 nude mice induced subcutaneously PSMA+ LNCaP cell line tumor. FIELD STRENGTH/SEQUENCE: 1.5 T, T2 -W Fast Spin echo and T2 *-W Gradient echo. ASSESSMENT: Coated IONPs with Carboxymethylated-dextran (DNPs) and with bovine serum albumin (BNPs), as well as, targeted DNPs with PSMA-11-HYNIC peptide (TDNPs) and targeted BNPs with PSMA-11-HBED peptide (TBNPs) were injected intravenously with dose 2.8 mg Fe/kg. Coronal T2 -W and the T2 *-W images were obtained before and 4 hours and 6 hours post-injection. Signal intensity (SI) and relative signal enhancement (RSE) were computed in two- and three-dimensional analyses. Histological analysis of tumors was evaluated, and the Fe distribution within the body based on atomic absorption spectroscopy was calculated. STATISTICAL TESTS: One-way ANOVA followed by Tukey's multiple comparison test, Paired-samples T-test, P < 0.05 was considered significant. RESULTS: A reduction in T2 -W SI was achieved as 22 ± 7%, 59 ± 3%, 65 ± 5%, and 78 ± 3% respectively for BNPs, TBNPs, DNPs, and TDNPs 6 hours post-injection. The most difference between targeted and non-targeted groups was observed at 6 hours for PSMA-11-HBED, and at 4 hours for PSMA-11-HYNIC. RSE indicated 88.6 ± 3.1% and 80.7 ± 3.2% enhanced contrast between tumor and muscle region for TBNPs and TDNPs on T2 *-W images. CONCLUSIONS: Both TBNPs and TDNPs are promising novel nano-molecular probes for PSMA+ PCa tumor detection. The injection dose of non-targeted IONPs can be reduced by using targeted nanoprobes three times for BNPs and two times for DNPs. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 1.
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Background: The accuracy of current laboratory and imaging studies for diagnosis and monitoring of Parkinson's disease (PD) severity is low and diagnosis is mainly dependent on clinical examination. Proton magnetic resonance spectroscopy (MRS) is a non-invasive technique that can assess the chemical profile of the brain. In this study, we evaluated the utility of proton MRS in diagnosis of PD and determination of its severity. Methods: Patients with PD and healthy age-matched controls were studied using proton MRS. The level of N-acetylaspartate (NAA), total creatine (Cr), and total choline (Cho), and their ratios were calculated in substantia nigra (SN), putamen (Pu), and motor cortex. PD severity was assessed by the Unified Parkinson's Disease Rating Scale (UPDRS) and the Hoehn and Yahr scale. Results: Compared to 25 healthy controls (18 men, age: 59.00 ± 8.39 years), our 30 patients with PD (24 men, age: 63.80 ± 12.00 years, 29 under treatment) showed no significant difference in the metabolite ratios in SN, Pu, and motor cortex. Nigral level of NAA/Cr was significantly correlated with total UPDRS score in patients with PD (r = -0.35, P = 0.08). Moreover, patients with PD with Hoehn and Yahr scale score ≥ 2 had a lower NAA/Cr level in SN compared to patients with a lower stage. Conclusion: This study shows that 1.5 tesla proton MRS is unable to detect metabolite abnormalities in patients with PD who are under treatment. However, the NAA/Cr ratio in the SN might be a useful imaging biomarker for evaluation of disease severity in these patients.
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OBJECTIVE: The gold standard for the diagnosis of lung cancer is conducting a histopathologic study. It is also diagnosed based on some features of a computed tomography (CT) scan. Imposed radiation is a prominent side effect of a CT scan. Diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) images have currently been used in the diagnosis of different lesions, including those of the brain and breast, and their uses in lung lesions are being evaluated. In this study, to find a safe, sensitive, and specific method, we aimed to assess DWI imaging to replace the CT scan and the positron emission tomography scan. MATERIAL AND METHODS: A total of 29 patients were enrolled in the study. In b800 images in DWI, spinal cord and lesion signals were measured, and the lesion-to-cord-signal ratio (LCR) was calculated. The ADC value was measured in a quantitative way. Lesions were also graded qualitatively in b800 DWI sequences. RESULTS: There was a significant difference between malignant and benign lesions in terms of DWI grading in b800 images (p<0.001). There was a significant difference between ADC means of a malignant and benign lesion (p=0.003). The mean LCR for malignant lung lesions was significantly higher than that of the benign ones (p<0.001). Considering Grade 3 as the cutoff in DWI grading results in sensitivity, specificity, and accuracy of 89%, 90%, and 89.6%, respectively. For ADC values, sensitivity, specificity, and accuracy of 79%, 80%, and 79.3%, respectively, were obtained when the cutoff was 1.027×10-3 sec/mm2. The sensitivity of 84%, the specificity of 90%, and the accuracy of 86.2% were calculated for the LCR in a cutoff of 0.983. In this study, all three parameters had an area under the curve of ≥0.8, meaning that these variables were valuable for the differentiation of benign and malignant lesions. CONCLUSION: Diffusion-weighted magnetic resonance imaging is a noninvasive tool, with no contrast agent and requiring ionizing radiations, which could be used for the qualitative, quantitative, and semiquantitative assessment of pulmonary lesions.
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Although the neuroanatomy of transgender persons is slowly being charted, findings are presently discrepant. Moreover, the major body of work has focused on Western populations. One important factor is the issue of power and low signal-to-noise (SNR) ratio in neuroimaging studies of rare study populations including endocrine or neurological patient groups. The present study focused on the structural neuroanatomy of a Non-Western (Iranian) sample of 40 transgender men (TM), 40 transgender women (TW), 30 cisgender men (CM), and 30 cisgender women (CW), while assessing whether the reliability of findings across structural anatomical measures including gray matter volume (GMV), cortical surface area (CSA), and cortical thickness (CTh) could be increased by using two back-to-back within-session structural MRI scans. Overall, findings in transgender persons were more consistent with sex assigned at birth in GMV and CSA, while no group differences emerged for CTh. Repeated measures analysis also indicated that having a second scan increased SNR in all regions of interest, most notably bilateral frontal poles, pre- and postcentral gyri and putamina. The results suggest that a simple time and cost-effective measure to improve SNR in rare clinical populations with low prevalence rates is a second anatomical scan when structural MRI is of interest.
