ABSTRACT
Objective:To evaluate the safety and efficacy of a dedicated neonatal-infant brain 0.35 T MRI system.Methods:A dual-center controlled clinical trial was conducted with single-arm objective performance criteria. From June to July 2020, sixty-six infants aged 0-12 (6.3±3.4) months were recruited from Children′s Hospital of Soochow University and the First People′s Hospital of Lianyungang prospectively. All infants underwent brain MRI with a dedicated neonatal-infant 0.35 T brain MRI system, using the dedicated two-channel transceiver head coil. MRI protocol included spin echo T 1WI, fast spin echo T 2WI, fluid attenuated inversion recovery, diffusion weighted imaging and 3D gradient echo sequence. MRI sequences were set with three orientations (axial, sagittal and coronal). Each case received at least two scanning planes and two scanning sequences. Five-point Likert scoring system was used to evaluate the image quality of acquired images, and the target value was set as at least 3 points per image. The temperature, heart rate and breathe of the infants were recorded before and after MRI; the acoustic noise of the MRI system was measured during the scanning process; and the adverse reactions were recorded if presented. Results:Five infants successfully completed their examination during non-sedated sleep in a single attempt, and 61 infants after sedation with chloral hydrate. Based on MRI-based five-point Likert scoring system, 41 cases achieved a score of 5, 21 cases with a score of 4 and 4 cases with a score of 3. Cases with score of 3 was due to movement of the infants during the scan, which resulted in motion related artifacts. The vital signs of all infants showed stable before and after imaging, with heart rate of (126.8±12.9) beats per minute, breathe of (38.2±6.8) times per minute. It was found that 47 cases showed no sign of temperature raise after brain MRI, 15 cases had less than 0.3 ℃ raise and 4 cases had 0.3 ℃ to 0.5 ℃ raise. The noise recorded during the scanning process was (57.5±1.8) dB(A). One case had mild diarrhea on the day of MR scan, and the symptoms disappeared on the second day without treatment; no adverse reactions were found for the rest subjects.Conclusion:Dedicated neonatal-infant 0.35 T brain MRI system allows data acquisition with high safety and excellent image quality, which has potentials in the clinical applications.
ABSTRACT
Objective:To investigate age-related morphological changes of the pancreas in healthy people using magnetic resonance imaging(MRI).Methods:From January 2017 to October 2019, people who took physical examinations at our hospital were enrolled and were divided into 7 groups according to age: 20-29 years old, 30-39 years old, 40-49 years old, 50-59 years old, 60-69 years old, 70-79 years old and ≥80 years.Also, the former four groups were classified as young and middle-aged(<60 years old)and the latter three as the elderly(≥60 years old). Morphological characteristics of the pancreas in each group were examined via MRI.Differences in parameters such as anteroposterior diameters of the head, body and tail and the pancreatic volume between the groups and the relationship between these parameters and age were analyzed.Results:A total of 191 cases who met the inclusion criteria were enrolled, including 96(50.3%)males and 95(49.7%)females, with 28 aged 20-29 years, 28 aged 30-39 years, 27 aged 40-49 years, 26 aged 50-59 years, 30 aged 60-69 years, 28 aged 70-79 years and 26 aged ≥80 years.There were 109 cases in the young and middle-aged category and 82 cases in the elderly category.MRI findings included pancreatic atrophy, which was most obvious in the tail; uneven and serrated edges of the pancreas and pancreatic lobulation; uneven signal intensity in the T 1-and T 2-weighted sequences; the "crispening effect" of pancreatic steatosis in the opposed-phase T 1-weighted sequences, and a trend of widening of the main pancreatic duct.The anteroposterior diameters of the pancreatic head, body and tail and the pancreatic volume reached the peak at(28.21±4.55)mm, (24.00±4.45)mm, (24.91±5.08)mm and(100.91±27.44)cm 3 between 30-39 years of age, and then gradually decreased to(18.87±3.82)mm, (15.63±3.96)mm, (13.70±3.70)mm and(43.88±10.47)cm 3 in those aged ≥80 years, with a decrease of 33.10%, 34.88%, 45.00% and 56.51%, respectively.The anteroposterior diameters of the pancreatic head, body, tail and the pancreatic volume in the elderly were(21.59±4.35)mm, (18.10±4.29)mm, (17.00±4.56)mm and(59.85±22.73)cm 3, which were smaller than those in the young and middle-aged category[(26.18±4.57)mm, (22.10±4.64)mm, (22.42±4.71)mm and(90.09±25.06)cm 3], and the differences were statistically significant( t=7.12, 6.19, 8.10 and 8.71, respectively, all P<0.001). The anteroposterior diameters of the head, body and tail and the pancreatic volume were negatively correlated with age( r=-0.52, -0.45, -0.56 and -0.57, respectively, P<0.001). Conclusions:The anteroposterior diameters of the head, body and tail and the pancreatic volume reach the peak between 30-39 years of age, and then gradually start to decline with the increase of age.After age 60, the decline become more evident, showing morphological signs of degeneration and dilatation of the main pancreatic duct.