Objective: To investigate the MRI findings of childhood granulocytic sarcoma (GS). Methods MRI data of 4 child patients with GS confirmed pathologically and immunohistochemistry were retrospectively analyzed. The location, size, morphology, signal characteristics, bone destruction and enhancement features of the tumor were observed. Results Among 4 patients, 3 cases were multiple, and 1 case was single. The lesion of 1 case was located in T3-T7 epidural intra-spinal canal and vertebral side, double side wall of maxillary sinus and sphenoid sinus, peri-orbit bone, of 1 case was located in L1-L2 epidural intra-spinal canal, of 1 case was located in T2-T4 and T10-T11 epidural intra-spinal canal, of 1 case was located in T11-T12 and L4-S2 level epidural intra-spinal canal, left side of the eye socket, sphenoid bone, and right side of the frontal sinus wall. Totally 4 cases were found soft tissue masses in the local or formed paravertebral lump through intervertebral foramen. The bone marrow signal of 3 cases was inhibited diffusely. MRI showed that T1WI signal slightly higher than normal surrounding muscles, while T2WI fat suppression showed slightly high signal intensity, and mild to moderate homogeneous enhancement. Two cases showed vertebral bone destruction, characterized by T1WI low signal obviously, T2WI fat suppression high signal obviously, and homogenous enhancement. Conclusion MRI features of GS of childhood have some characteristics, and they are helpful for diagnosis of GS.

Objective To evaluate the imaging characteristics of atypical teratoid/rhab doid tumor (AT/RT) of central nervous system(CNS), and to improve the diagnostic ability of the disease. Methods The clinical and imaging findings of 9 patients were retrospectively analyzed. There were 5 male and 4 female, ages 7 months to 5 years,median age was 1.4 years. MR enhancement studies were obtained in all the cases. One case had CT enhancement examination. Results The lesions were seen in brain in 8 cases and in lumbosacral spinal cord in one case. The tumors size varied from 4.8—7.8 cm, Necrosis was seen in nine cases, cystic change in eight cases and hemorrhage in five cases. The tumors had high signal on DWI, and low signal on ADC map. Dura matter invasion(2 cases), cerebrospinal fluid spread(2 cases)and intracerebral metastasis were seen. Conclusion There are some relatively specific imaging findings of primary CNS AT/RT that could assist their diagnosis.

Objective To assess the characteristics of facial nerve canal between normal anatomy and dysplasia of children in different ages.Methods A total of 492 health ears were divided into six groups,neonatal group (＜ 1 m,n =42),infancy group(1 m-1 y,n =106),toddler group(1-3 y,n =102),preschool group (3-6 y,n =100),school group(6-10 y,n =60)and adolescent group (10-14 y,n =82).The length and diameter of facial nerve canal and that angles of first and second genu were measured with CT in each group.Results ①The lengths of facial nerve canal in neonatal and infancy group were shorter than other four groups,especially in the mastoid segments of facial nerve canal.The lengths of mastoid segments in neonatal,infancy,toddler,preschool,school and adolescent groups were 5.03 ± 0.84,6.25± 1.40,8.34 ± 1.38,9.70 ± 1.34,10.84 ± 1.41 and 12.17 ± 1.83 mm,with P ＜0.05,respectively.After school age,the lengths of labyrinthine and tympanic segment grew slowly or developed completely (P ＞ 0.05).② The diameter of labyrinth and tympanic segment in neonatal group were narrower than other five groups (P ＜ 0.05),but no significant difference among them in other groups (P ＞ 0.05).③The dysplasia of facial nerve canal were occurred on 978 locations.Among them,the percentage of dehiscence,aberrance,partially expanding and bifurcation were 72.9％ (713/978),5.1％ (50/978),18.9％ (185/978) and 3.1％ (30/978) respectively.The percentage of dehiscence in geniculate fossa segment was decreased significantly with age (neonatal group 85.7％ (36/42),infancy group 59.4％ (63/106),toddler group 39.2％ (40/102),preschool group 33％ (33/100),school group 30％ (18/60) and adolescent group 26.8％ (22/82),with P ＜ 0.05).Except the dehiscence of geniculate fossa and mastoid segment,there was no significant difference in the occurrence rate of the other variants (P ＞ O.05) Conclusions The growth of length and dehiscence in labyrinth segment of facial nerve canal are significant in difference ages.The changes of diameter and angles of first and second genu in facial nerve canal,and the rate of other dysplasia are individual.