核医学显像探针在肿瘤PD-L1免疫治疗中的应用

程序化死亡配体-1（PD-L1）靶向免疫治疗被广泛应用于不同类型的癌症中，患者从PD-L1靶向免疫治疗的获益主要依赖于肿瘤组织PD-L1的表达水平。目前临床主要采用穿刺活检等有创手段来评价肿瘤组织PD-L1的表达水平，严重受限于PD-L1表达的时间和空间异质性。核医学探针能够在分子水平上实现对PD-L1的在体无创检测，对于指导患者筛选、预测患者免疫治疗响应具有重要的临床意义。本文综述了靶向PD-L1的核医学分子影像探针，并讨论其在肿瘤PD-L1显像中的应用。     

MRI characteristics of MOG-Ab associated disease in adults: An update

Our knowledge of the radiological spectrum of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is growing rapidly. An update on the radiological features of the disease, and its evolution is thus necessary. Magnetic resonance imaging (MRI) has an increasingly important role in the differential diagnosis of MOGAD particularly from aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and multiple sclerosis (MS). Differentiating these conditions is of prime importance because the management is different between the three inflammatory diseases, and thus could prevent further attack-related disability. Therefore, identifying the MRI features suggestive of MOGAD has diagnostic and prognostic implications. We herein review optic nerve, spinal cord and the brain MRI findings from MOGAD adult patients, and compare them to AQP4-NMOSD and MS.     

Synthetic MRI is not yet ready for morphologic and functional assessment of patellar cartilage at 1.5 Tesla

PurposeThe purpose of this study was to compare morphologic assessment and relaxometry of patellar hyaline cartilage between conventional sequences (fast spin-echo [FSE] T2-weighted fat-saturated and T2-mapping) and synthetic T2 short-TI inversion recovery (STIR) and T2 maps at 1.5 T magnetic resonance imaging (MRI).MethodThe MRI examinations of the knee obtained at 1.5 T in 49 consecutive patients were retrospectively studied. There were 21 men and 28 women with a mean age of 45 ± 17.7 (SD) years (range: 18–88 years). Conventional and synthetic acquisitions were performed, including T2-weighted fat-saturated and T2-mapping sequences. Two radiologists independently compared patellar cartilage T2-relaxation time on conventional T2-mapping and synthetic T2-mapping images. A third radiologist evaluated the patellar cartilage morphology on conventional and synthetic T2-weighted images. The presence of artifacts was also assessed. Interobserver agreement for quantitative variables was assessed using intraclass correlation coefficient (ICC).ResultsIn vitro, conventional and synthetic T2 maps yielded similar mean T2 values 58.5 ± 2.3 (SD) ms and 58.8 ± 2.6 (SD) ms, respectively (P = 0.414) and 6% lower than the expected experimental values (P = 0.038). Synthetic images allowed for a 15% reduction in examination time compared to conventional images. On conventional sequences, patellar chondropathy was identified in 35 patients (35/49; 71%) with a mean chondropathy grade of 4.8 ± 4.8 (SD). On synthetic images, 28 patients (28/49; 57%) were diagnosed with patellar chondropathy, with a significant 14% difference (P = 0.009) and lower chondropathy scores (3.7 ± 4.9 [SD]) compared to conventional images. Motion artifacts were more frequently observed on synthetic images (18%) than on conventional ones (6%). The interobserver agreement was excellent for both conventional and synthetic T2 maps (ICC > 0.83). Mean cartilage T2 values were significantly greater on synthetic images (36.2 ± 3.8 [SD] ms; range: 29-46 ms) relative to conventional T2 maps (31.8 ± 4.1 [SD] ms; range: 26-49 ms) (P < 0.0001).ConclusionDespite a decrease in examination duration, synthetic images convey lower diagnostic performance for chondropathy, greater prevalence of motion artifacts, and an overestimation of T2 values compared to conventional MRI sequences.     

Effect of body position on qualitative and quantitative ultrasound assessment of gastric fluid contents

We assessed the impact of raising the upper section of the bed, and patient positioning, on ultrasound assessment of gastric fluid contents. We performed ultrasound examinations in 25 subjects lying on their back, left and right sides at bed angles of 0°, 30°, 45° and 90°; this was carried out while the subjects were fasted, and repeated 10 min after drinking ≥ 50 ml water. After drinking, gastric contents were detected more frequently in the 45° semirecumbent position compared with the supine and 30° positions. The diagnostic performance of the Perlas qualitative grading scale to detect gastric fluid volume > 1.5 ml.kg⁻¹ was improved at 45°, compared with 0° and 30° angles. The use of a composite ultrasound grading scale at a 45° angle was associated with the best performance, with a sensitivity and specificity of 82%. Antral cross-sectional area was significantly increased when measured in the right lateral position, but there was no effect of raising the bed. In conclusion, raising the upper section of the bed significantly affected qualitative assessment of gastric fluid contents. Further studies are required to determine the most appropriate composite ultrasound grading scale and bed angle for fast and reliable qualitative ultrasound detection of fluid volumes > 1.5 ml.kg⁻¹.     

Maximal calf circumference reflects calf muscle mass measured using magnetic resonance imaging

BackgroundCalf circumference (CC) has been used as a surrogate for calf muscle mass, which facilitates venous blood return to the heart through active skeletal muscle. However, the correlation between CC and calf muscle mass has not been extensively examined. This study aimed to examine the relationship between CC and calf muscle mass considering differences in sex and physique in elderly individuals.MethodsA total of 124 community-dwelling elderly individuals ≥60 years of age (61 men, mean [±SD] age 74.3 ± 5.7 years) were enrolled. Maximal CC was measured using a tape measure with the subject supine. The cross-sectional area of skeletal muscle tissues was measured using magnetic resonance imaging from the point of greatest calf circumference to 5 cm proximal and distal. Calf muscle mass was calculated by multiplying the area of each slice by slice thickness (5 mm).ResultsCC was strongly correlated with calf muscle mass in male and female subjects (male: r = 0.908, P < 0.001; female: r = 0.892, P < 0.001). Multiple regression analysis revealed that CC and body mass index (BMI) were independent associate factors of calf muscle mass. The following estimation formulae were derived: (male) calf muscle mass (cm³) = 47.82 × CC (cm)−12.50 × BMI (kg/m²) −732.80; (female) calf muscle mass (cm³) = 32.23 × CC (cm) −4.85 × BMI (kg/m²) −429.94.ConclusionsA strong correlation was found between CC and calf muscle mass according to magnetic resonance imaging. Sex differences and BMI should be considered for accurate estimation of calf muscle mass using CC.     

综述三维斑点追踪技术在糖尿病心肌病心功能评价中的应用

糖尿病心肌病(Diabetic Cardiomyopathy,DC)的进展会导致左心室功能减低,因此,早期正确评估左心室功能对糖尿病心肌病患者的治疗和预后有着重要的意义。由于左心室解剖结构的复杂性,常规超声技术通常很难准确的评估左心室功能的变化,三维斑点追踪技术(three-dimensional speckle tracking imaging,3D-STI)是在实时3D超声和斑点追踪技术(STI)基础上发展起来的一项新技术,其对心脏功能的评估不受整个心脏运动方向和运动幅度的限制,能够直观的对心肌各个方向的运动进行追踪。本文首先论述3D-STI 在左心室功能评价中的可行性,再对其在DC左心室功能评价中的研究展开综述。