The targeted delivery of superparamagnetic iron oxide nanoparticles (SPIONs) as a contrast agent may facilitate their accumulation in cancer cells and enhance the sensitivity of MR imaging. In this study, SPIONs coated with dextran (DSPIONs) were conjugated with bombesin (BBN) to produce a targeting contrast agent for detection of breast cancer using MRI. X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer analyses indicated the formation of dextran-coated superparamagnetic iron oxide nanoparticles with an average size of 6.0 ± 0.5 nm. Fourier transform infrared spectroscopy confirmed the conjugation of the BBN with the DSPIONs. A stability study proved the high optical stability of DSPION-BBN in human blood serum. DSPION-BBN biocompatibility was confirmed by cytotoxicity evaluation. A binding study showed the targeting ability of DSPION-BBN to bind to T47D breast cancer cells overexpressing gastrin-releasing peptide (GRP) receptors. T2-weighted and T2*-weighted color map MR images were acquired. The MRI study indicated that the DSPION-BBN possessed good diagnostic ability as a GRP-specific contrast agent, with appropriate signal reduction in T2*-weighted color map MR images in mice with breast tumors.

BackgroundPreventing sepsis‐associated acute kidney injury (S‐AKI) can be challenging because it develops rapidly and is often asymptomatic. Probability assessment of disease progression for therapeutic follow‐up and outcome are important to intervene and prevent further damage.PurposeTo establish a noninvasive multiparametric MRI (mpMRI) tool, including T1, T2, and perfusion mapping, for probability assessment of the outcome of S‐AKI.Study TypePreclinical randomized prospective study.Animal ModelOne hundred and forty adult female SD rats (65 control and 75 sepsis).Field Strength/Sequence9.4T; T1 and perfusion map (FAIR‐EPI) and T2 map (multiecho RARE).AssessmentExperiment 1: To identify renal injury in relation to sepsis severity, serum creatinine levels were determined (31 control and 35 sepsis). Experiment 2: Animals underwent mpMRI (T1, T2, perfusion) 18 hours postsepsis. A subgroup of animals was immediately sacrificed for histology examination (nine control and seven sepsis). Result of mpMRI in follow‐up subgroup (25 control and 33 sepsis) was used to predict survival outcomes at 96 hours.Statistical TestsMann–Whitney U test, Spearman/Pearson correlation (r), P < 0.05 was considered statistically significant.ResultsSeverely ill septic animals exhibited significantly increased serum creatinine levels compared to controls (70 ± 30 vs. 34 ± 9 μmol/L, P < 0.0001). Cortical perfusion (480 ± 80 vs. 330 ± 140 mL/100 g tissue/min, P < 0.005), and cortical and medullary T2 relaxation time constants were significantly reduced compared to controls (41 ± 4 vs. 37 ± 5 msec in cortex, P < 0.05, 52 ± 7 vs. 45 ± 6 msec in medulla, P < 0.05). The combination of cortical T2 relaxation time constants and perfusion results at 18 hours could predict survival outcomes at 96 hours with high sensitivity (80%) and specificity (73%) (area under curve of ROC = 0.8, Jmax = 0.52).Data ConclusionThis preclinical study suggests combined T2 relaxation time and perfusion mapping as first line diagnostic tool for treatment planning.Level of Evidence2Technical Efficacy Stage2

Background: Scar tissue formation is a common phenomenon in myocardial infarctions. Contrast-enhanced cardiac magnetic resonance imaging is the modality of choice to evaluate the location and size of the scar tissue. Nevertheless, in patients with severe kidney impairment, administration of gadolinium is contraindicated. Objectives: So the aim of this study was to substitute a safe way for myocardial infarction assessments in patients with a history of renal function impairment. We assessed the T2* quantitative value changes in myocardial infarction-related scar tissue and compared them with normal/remote myocardial tissue T2* values to evaluate its application in non-contrast cardiac magnetic resonance imaging viability assessments. Patients and Methods: Twenty patients with a previous history of non ST-elevation myocardial infarction (NSTEMI) underwent cardiac magnetic resonance (CMR) examination with a 1.5T MR imaging scanner (Avanto, Siemens AG Healthcare Sector, Erlangen, Germany). The time interval between myocardial infarction occurrence and CMR assessment was at least six months. All the patients had normal kidney function. The imaging protocol consisted of three steps: the functional left-ventricular imaging; 8-echoes gradient recalled echo T2* mapping; and delayed/late gadolinium-enhancement imaging. The left-ventricle functional and T2* mapping assessments were done by CMR42 image analysis software (Circle Cardiovascular Imaging, Calgary, Canada). T2* values were calculated for 49 regions of interests (ROIs) at the infarction (14 ROIs), peri-infarction (12 ROIs), and remote/normal myocardial tissues (23 ROIs), and their means were compared statistically by the Leven's test. Finally, the receiver operator characteristics curve was calculated. Results: T2* (mean ± SD) values of the normal/remote, peri-infarction, and infarcted myocardial tissues were calculated as 29.42 ± 4.50, 30.71 ± 4.86, and 35.46 ± 3.61, respectively. There was a significant alteration in the post-infarction scar tissue's myocardial T2* values by comparison with the normal/remote myocardium (P < 0.001). No significant differences were noticed between the normal/remote and peri-infarction regions' T2* relaxation times (P > 0.05). Area under the curve was 81% for patients evaluated for scars. Cutoff value of 31.70 yielded 92% sensitivity and 72% specificity. Conclusion: T2* relaxation time can provide useful and sensitive information on scar tissue formation location, and can offer a greater sensitivity into the non-contrast CMR imaging viability assessments besides other relaxation phenomena, especially the longitudinal relaxation time.

Objective. In hypertrophic cardiomyopathy (HCM), myocardial fibrosis is routinely shown by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) imaging. We evaluated the efficacy of 2 novel contrast-free CMR methods, namely, diffusion-weighted imaging (DWI) and feature-tracking (FT) method, in detecting myocardial fibrosis. Methods. This cross-sectional study was conducted on 26 patients with HCM. Visual and quantitative comparisons were made between DWI and LGE images. Regional longitudinal, circumferential, and radial strains were compared between LGE-positive and LGE-negative segments. Moreover, global strains were compared between LGE-positive and LGE-negative patients as well as between patients with mild and marked LGE. Results. All 3 strains showed significant differences between LGE-positive and LGE-negative segments ( P < 0.001 ). The regional longitudinal and circumferential strain parameters showed significant associations with LGE ( P < 0.001 ), while regional circumferential strain was the only independent predictor of LGE in logistic regression models (OR: 1.140, 95% CI: 1.073 to 1.207, P < 0.001 ). A comparison of global strains between patients with LGE percentages of below 15% and above 15% demonstrated that global circumferential strain was the only parameter to show impairment in the group with marked myocardial fibrosis, with borderline significance ( P = 0.09 ). A review of 212 segments demonstrated a qualitative visual agreement between DWI and LGE in 193 segments (91%). The mean apparent diffusion coefficient was comparable between LGE-positive and LGE-negative segments ( P = 0.51 ). Conclusions. FT-CMR, especially regional circumferential strain, can reliably show fibrosis-containing segments in HCM. Further, DWI can function as an efficient qualitative method for the estimation of the fibrosis extent in HCM.

Background: Although new approaches for application of magnetic resonance imaging (MRI) in dentistry have been promising, the presence of dental materials in the oral cavity represents a major obstacle to generating quality MRI data. The resulting artifacts can adversely affect diagnostic accuracy of oral and maxillofacial conditions. Objectives: This study aimed to detect and assess artifacts caused by metallic and non-metallic dental materials in MR images. Materials and Methods: Nineteen commonly used dental materials were used in an in vitro assay. An empty cube-shaped phantom