Magnetic resonance imaging of the brainstem in children, part 1: imaging techniques, embryology, anatomy and review of congenital conditions.

Part 1 of this series of two articles describes conventional and advanced MRI techniques that are useful for evaluating brainstem pathologies. In addition, it provides a review of the embryology, normal progression of myelination, and clinically and radiologically salient imaging anatomy of the normal brainstem. Finally, it discusses congenital diseases of the brainstem with a focus on distinctive imaging features that allow for differentiating pathologies. Part 2 of this series of two articles includes discussion of neoplasms; infections; and vascular, demyelinating, toxic and metabolic, and miscellaneous disease processes affecting the brainstem. The ultimate goal of this pair of articles is to empower the radiologist to add clinical value in the care of pediatric patients with brainstem pathologies.

68Ga-DOTATATE: Significance of Uptake in the Tail of the Pancreas in Patients Without Lesions.

PURPOSE: To measure the SUVs in the tail of the pancreas compared with normal liver parenchyma and somatostatin receptor-positive lesions. MATERIALS AND METHODS: Ga-DOTATATE PET/low mAs CT of 35 patients were reviewed. RESULTS: There was no significant difference (P = 0.59) between the SUVaverage of normal liver and the SUVpeak of normal tail. Five patients had uptake in the tail slightly above that of normal liver that were interpreted equivocally. In one of these patients with Ga-DOTATATE uptake in a peripancreatic lymph node, proven neuroendocrine tumor underwent a distal pancreatectomy and pathologic examination revealed islet cell hyperplasia. CONCLUSIONS: Ga-DOTATATE uptake in the tail of the pancreas above that of normal liver indicates a somatostatin receptor-avid lesion. Uptake in the tail of the pancreas equal to the liver can be normal. Patients with uptake equivalent to the liver should undergo further anatomical imaging before procedural intervention.

Association between image-defined risk factors and neuroblastoma outcomes.

BACKGROUND: The current neuroblastoma (NBL) staging system employs image-defined risk factors (IDRFs) to assess numerous anatomic features, but the impact of IDRFs on surgical and oncologic outcomes is unclear. METHODS: The Vanderbilt Cancer Registry identified children treated for NBL from 2002 to 2017. Tumor volume (TV) and IDRFs were measured radiographically at diagnosis and before resection. Perioperative and oncologic outcomes were evaluated. RESULTS: At diagnosis of 106 NBL, 61% were IDRF positive. MYCN-amplified and undifferentiated NBL had more IDRFs than nonamplified and more differentiated tumors (p = 0.001 and p = 0.01). Of 86 NBLs resected, 43% were IDRF positive, which associated with higher stage, risk, and TV (each p < 0.001). The presence of IDRF at resection was also associated with increased blood loss (p < 0.001), longer operating times (p < 0.001), greater incidence of intraoperative complications (p = 0.03), more frequent ICU admissions postoperatively (p < 0.001), and longer hospital stays (p < 0.001). IDRF negative and positive tumors did not have significantly different rates of gross total resection (p = 0.2). Five-year relapse-free and overall survival was similar for IDRF negative and positive NBL (p = 0.9 and p = 0.8). CONCLUSIONS: IDRFs at diagnosis were associated with larger, less differentiated, advanced stage, and higher risk NBL and at resection with increased operative difficulty and perioperative morbidity. However, the frequency of gross total resection and patient survival after resection were not associated with the presence of IDRFs. TYPE OF STUDY: Retrospective cohort study. LEVEL OF EVIDENCE: Level III.

Maintaining oncologic integrity with minimally invasive resection of pediatric embryonal tumors.

BACKGROUND: Embryonal tumors arise typically in infants and young children and are often massive at presentation. Operative resection is a cornerstone in the multimodal treatment of embryonal tumors but potentially disrupts therapeutic timelines. When used appropriately, minimally invasive surgery can minimize treatment delays. The oncologic integrity and safety attainable with minimally invasive resection of embryonal tumors, however, remains controversial. METHODS: Query of the Vanderbilt Cancer Registry identified all children treated for intracavitary, embryonal tumors during a 15-year period. Tumors were assessed radiographically to measure volume (mL) and image-defined risk factors (neuroblastic tumors only) at time of diagnosis, and at preresection and postresection. Patient and tumor characteristics, perioperative details, and oncologic outcomes were compared between minimally invasive surgery and open resection of tumors of comparable size. RESULTS: A total of 202 patients were treated for 206 intracavitary embryonal tumors, of which 178 were resected either open (n = 152, 85%) or with minimally invasive surgery (n = 26, 15%). The 5-year, relapse-free, and overall survival were not significantly different after minimally invasive surgery or open resection of tumors having a volume less than 100 mL, corresponding to the largest resected with minimally invasive surgery (P = .249 and P = .124, respectively). No difference in margin status or lymph node sampling between the 2 operative approaches was detected (p = .333 and p = .070, respectively). Advantages associated with minimally invasive surgery were decreased blood loss (P < .001), decreased operating time (P = .002), and shorter hospital stay (P < .001). Characteristically, minimally invasive surgery was used for smaller volume and earlier stage neuroblastic tumors without image-defined risk factors. CONCLUSION: When selected appropriately, minimally invasive resection of pediatric embryonal tumors, particularly neuroblastic tumors, provides acceptable oncologic integrity. Large tumor volume, small patient size, and image-defined risk factors may limit the broader applicability of minimally invasive surgery.