Arterial spin labelling: predictive role in surgical bleeding of paediatric optic pathway gliomas

AIM

To analyse the performance of arterial spin labelling (ASL) in predicting surgical bleeding in a paediatric cohort of optic pathway glioma (OPG).

MATERIALS AND METHODS

Preoperative ASL data were obtained for 51 OPG in 40 patients, aged from 9 months to 16 years. The relative cerebral blood flow (rCBF) in the tumour areas with the highest CBF (maximum rCBF) was measured and then correlated with qualitative local bleeding (graded no, moderate, and major by the neurosurgeon) and quantitative global surgical bleeding (assessed in millilitres using haematocrit data).

RESULTS

Intratumoural maximum rCBF was significantly higher when qualitative local bleeding was high (median value in the no, moderate, and major bleeding groups equal to 0.81, 1.39 and 4.22, respectively, p=0.004), but there was no difference in global quantitative bleeding (p=0.7 for the total blood loss). The maximum tumour rCBF cut-off value of 1.1 yielded a sensitivity of 73%, a specificity of 78%, and an accuracy of 76% (39/51 tumours) in detecting haemorrhagic OPG. Choosing a maximum tumour rCBF cut-off value > 1.7 improved the specificity in diagnosing tumours with high bleeding risk with a specificity of 94%, a sensitivity of 53%, and an accuracy of 82% (42/51 tumours).

CONCLUSION

ASL tumoural rCBF is a useful and simple diagnostic tool to help predict high intraoperative tumoural bleeding risk in paediatric OPG.

Noninvasive Follow-up Imaging of Ruptured Pediatric Brain AVMs Using Arterial Spin-Labeling

BACKGROUND AND PURPOSE

Brain AVMs represent the main etiology of pediatric intracranial hemorrhage. Noninvasive imaging techniques to monitor the treatment effect of brain AVMs remain an unmet need. In a large cohort of pediatric ruptured brain AVMs, we aimed to investigate the role of arterial spin-labeling for the longitudinal follow-up during treatment and after complete obliteration by analyzing CBF variations across treatment sessions.

MATERIALS AND METHODS

Consecutive patients with ruptured brain AVMs referred to a pediatric quaternary care center were prospectively included in a registry that was retrospectively queried for children treated between 2011 and 2019 with unimodal or multimodal treatment (surgery, radiosurgery, embolization). We included children who underwent an arterial spin-labeling sequence before and after treatment and a follow-up DSA. CBF variations were analyzed in univariable analyses.

RESULTS

Fifty-nine children with 105 distinct treatment sessions were included. The median CBF variation after treatment was -43 mL/100 mg/min (interquartile range, -102-5.5), significantly lower after complete nidal surgical resection. Following radiosurgery, patients who were healed on the last DSA follow-up demonstrated a greater CBF decrease on intercurrent MR imaging, compared with patients with a persisting shunt at last follow-up (mean, -62 [SD, 61] mL/100 mg/min versus -17 [SD, 40.1] mL/100 mg/min; P = .02). In children with obliterated AVMs, recurrences occurred in 12% and resulted in a constant increase in CBF (mean, +89 [SD, 77] mL/100 mg/min).

CONCLUSIONS

Our results contribute data on the role of noninvasive arterial spin-labeling monitoring of the response to treatment or follow-up after obliteration of pediatric AVMs. Future research may help to better delineate how arterial spin-labeling can assist in decisions regarding the optimal timing for DSA.

Risk Factors for Early Brain AVM Rupture: Cohort Study of Pediatric and Adult Patients

BACKGROUND AND PURPOSE

Whether architectural characteristics of ruptured brain AVMs vary across the life span is unknown. We aimed to identify angioarchitectural features associated with brain AVMs ruptured early in life.

MATERIALS AND METHODS

Patients with ruptured brain AVMs referred to 2 distinct academic centers between 2000 and 2018 were pooled and retrospectively analyzed. Imaging was retrospectively reviewed for angioarchitectural characteristics, including nidus size, location, Spetzler-Martin grade, venous drainage, and arterial or nidal aneurysm. Angioarchitecture variations across age groups were analyzed using uni- and multivariable models; then cohorts were pooled and analyzed using Kaplan-Meier and Cox models to determine factors associated with earlier rupture.

RESULTS

Among 320 included patients, 122 children (mean age, 9.8 ± 3.8 years) and 198 adults (mean age, 43.3 ± 15.7 years) were analyzed. Pediatric brain AVMs were more frequently deeply located (56.3% versus 21.2%, P < .001), with a larger nidus (24.2  versus 18.9 mm, P = .002), were less frequently nidal (15.9% versus 23.5%, P = .03) and arterial aneurysms (2.7% versus 17.9%, P < .001), and had similar drainage patterns or Spetzler-Martin grades. In the fully adjusted Cox model, supratentorial, deep brain AVM locations (adjusted relative risk, 1.19; 95% CI, 1.01-1.41; P = .03 and adjusted relative risk, 1.43; 95% CI, 1.22-1.67; P < .001, respectively) and exclusively deep venous drainage (adjusted relative risk, 1.46, 95% CI, 1.21-1.76; P < .001) were associated with earlier rupture, whereas arterial or nidal aneurysms were associated with rupture later in life.

CONCLUSIONS

The angioarchitecture of ruptured brain AVMs significantly varies across the life span. These distinct features may help to guide treatment decisions for patients with unruptured AVMs.

Focal Areas of High Signal Intensity in Children with Neurofibromatosis Type 1: Expected Evolution on MRI

BACKGROUND AND PURPOSE

Focal areas of high signal intensity are T2WI/T2-FLAIR hyperintensities frequently found on MR imaging of children diagnosed with neurofibromatosis type 1, often thought to regress spontaneously during adolescence or puberty. Due to the risk of tumor in this population, some focal areas of high signal intensity may pose diagnostic problems. The objective of this study was to assess the characteristics and temporal evolution of focal areas of high signal intensity in children with neurofibromatosis type 1 using long-term follow-up with MR imaging.

MATERIALS AND METHODS

We retrospectively examined the MRIs of children diagnosed with neurofibromatosis type 1 using the National Institutes of Health Consensus Criteria (1987), with imaging follow-up of at least 4 years. We recorded the number, size, and surface area of focal areas of high signal intensity according to their anatomic distribution on T2WI/T2-FLAIR sequences. A generalized mixed model was used to analyze the evolution of focal areas of high signal intensity according to age, and separate analyses were performed for girls and boys.

RESULTS

Thirty-nine patients (ie, 285 MR images) with a median follow-up of 7 years were analyzed. Focal areas of high signal intensity were found in 100% of patients, preferentially in the infratentorial white matter (35% cerebellum, 30% brain stem) and in the capsular lenticular region (22%). They measured 15 mm in 95% of cases. They appeared from the age of 1 year; increased in number, size, and surface area to a peak at the age of 7; and then spontaneously regressed by 17 years of age, similarly in girls and boys.

CONCLUSIONS

Focal areas of high signal intensity are mostly small (<15 mm) abnormalities in the posterior fossa or capsular lenticular region. Our results suggest that the evolution of focal areas of high signal intensity is not related to puberty with a peak at the age of 7 years. Knowledge of the predictive evolution of focal areas of high signal intensity is essential in the follow-up of children with neurofibromatosis type 1.

CT and Multimodal MR Imaging Features of Embryonal Tumors with Multilayered Rosettes in Children

BACKGROUND AND PURPOSE

Embryonal tumors with multilayered rosettes, C19MC-altered, are brain tumors occurring in young children, which were clearly defined in the 2016 World Health Organization classification of central nervous system neoplasms. Our objective was to describe the multimodal imaging characteristics of this new entity.

MATERIALS AND METHODS

We performed a retrospective monocentric review of embryonal brain tumors and looked for embryonal tumors with multilayered rosettes with confirmed C19MC alteration. We gathered morphologic imaging data, as well as DWI and PWI data (using arterial spin-labeling and DSC).

RESULTS

We included 16 patients with a median age of 2 years 8 months. Tumors were both supratentorial (56%, 9/16) and infratentorial (44%, 7/16). Tumors were large (median diameter, 59 mm; interquartile range, 48-71 mm), with absent (75%, 12/16) or minimal (25%, 4/16) peritumoral edema. Enhancement was absent (20%, 3/15) or weak (73%, 11/15), whereas intratumoral macrovessels were frequently seen (94%, 15/16) and calcifications were present in 67% (10/15). Diffusion was always restricted, with a minimal ADC of 520 mm²/s (interquartile range, 495-540 mm²/s). Cerebral blood flow using arterial spin-labeling was low, with a maximal CBF of 43 mL/min/100 g (interquartile range, 33-55 mL/min/100 g 5). When available (3 patients), relative cerebral blood volume using DSC was high (range, 3.5-5.8).

CONCLUSIONS

Embryonal tumors with multilayered rosettes, C19MC-altered, have characteristic imaging features that could help in the diagnosis of this rare tumor in young children.

Cerebral Blood Flow Improvement after Indirect Revascularization for Pediatric Moyamoya Disease: A Statistical Analysis of Arterial Spin-Labeling MRI

BACKGROUND AND PURPOSE

The severity of Moyamoya disease is generally scaled with conventional angiography and nuclear medicine. Arterial spin-labeling MR imaging is now acknowledged for the noninvasive quantification of cerebral blood flow. This study aimed to analyze CBF modifications with statistical parametric mapping of arterial spin-labeling MR imaging in children undergoing an operation for Moyamoya disease.

MATERIALS AND METHODS

We included 15 children treated by indirect cerebral revascularization with multiple burr-holes between 2011 and 2013. Arterial spin-labeling MR imaging and T1 sequences were then analyzed under SPM8, according to the general linear model, before and after the operation (3 and 12 months). Voxel-based analysis was performed at the group level, comparing all diseased hemispheres with all normal hemispheres and, at the individual level, comparing each patient with a control group.

RESULTS

Group analysis showed statistically significant preoperative hypoperfusion in the MCA territory in the Moyamoya hemispheres and a significant increase of cerebral perfusion in the same territory after revascularization (P < .05 family-wise error-corrected). Before the operation, individual analysis showed significant hypoperfusion for each patient co-localized with the angiographic defect on DSA. All except 1 patient had improvement of CBF after revascularization, correlated with their clinical status.

CONCLUSIONS

SPM analysis of arterial spin-labeling MR imaging offers a noninvasive evaluation of preoperative cerebral hemodynamic impairment and an objective assessment of postoperative improvement in children with Moyamoya disease.

Pediatric sinogenic epidural and subdural empyema: The role of endoscopic sinus surgery

AIM

To analyze the indications and outcomes of open neurosurgical approaches (ONA) and endoscopic transnasal approaches (ETA) in the surgical management of pediatric sinogenic subdural and epidural empyema.

MATERIAL AND METHODS

Retrospective single-center study design within a tertiary care referral center setting. Children less than 18 years of age consecutively operated on between January 2012 and February 2014 for drainage of a sinogenic subdural empyema (SE) or epidural (EE) empyema were included.

MAIN OUTCOME MEASURES

success of first surgical procedure, persistent symptoms and sequelae at the end of the follow-up period.

RESULTS

Nine SE (53%) and 8 EE (47%) were observed. Neurological symptoms, especially seizures, were more frequent in the SE group. Perioperative pus samples were positive in 67% of the SE group and in 75% of the EE group. The most frequently isolated bacteria belonged to the Streptococcus anginosus group. CT or MR imaging showed that most empyema probably originated from the frontal sinus. However, two cases resulted from an ethmoiditis and one case from a Pott's puffy tumor, without any direct contact with the paranasal sinus. In cases of SE, the most effective surgical technique was ONA with craniotomy. Associated endoscopic sinus drainage was useful for the purpose of bacteriological diagnosis. In cases of EE, effectiveness was noted in both ONA and ETA techniques. In two cases of EE, the ETA procedure encompassed direct drainage of the empyema through the posterior wall of the frontal sinus (Draf III approach). The number of patients successfully treated after a single surgical procedure was higher in the EE group (p=0.05). Regarding outcomes, no mortalities were observed. Persistent disorders at the end of the follow-up period, especially headaches, cognitive, concentration or schooling problems, tended to be more frequent in the SE group than in the EE group (67% vs 29%), and were more commonly observed in cases requiring several surgical procedures (75% vs 12.5%) (p=0.05).

DISCUSSION

Endoscopic sinus surgery plays a critical role in the surgical management of pediatric sinogenic SE and EE. In cases of small volume EE, the endoscopic approach associated with antibiotherapy may be sufficient to treat the infectious process.

Choroid Plexus Neoplasms: Toward a Distinction between Carcinoma and Papilloma Using Arterial Spin-Labeling

Pediatric choroid plexus papillomas and carcinomas are highly vascularized neoplasms, which are difficult to distinguish with conventional imaging. We aimed to analyze the diagnostic accuracy of PWI, by using both pseudocontinuous arterial spin-labeling and DSC-PWI. We reviewed the PWI of 13 children with choroid plexus neoplasms (7 papillomas and 6 carcinomas). We quantified CBF, relative CBF, and relative CBV in each lesion and compared papillomas and carcinomas. Relative CBF values by using arterial spin-labeling were significantly higher for carcinomas (P = .028). The median value of relative CBF was 1.7 (range, 1.4-1.9) for carcinomas and 0.4 (range, 0.3-0.6) for papillomas. The CBF median value was 115 mL/min/100 g (range, 90-140 mL/min/100 g) for carcinomas and 41 mL/min/100 g (range, 10-73 mL/min/100 g) for papillomas (P = .056). Measures with DSC-PWI were more variable and not significantly different (P = .393). Arterial spin-labeling is a promising technique to differentiate choroid plexus carcinomas and papillomas.

Hippocampus and epilepsy: Findings from human tissues

Surgical removal of the epileptogenic zone provides an effective therapy for several focal epileptic syndromes. This surgery offers the opportunity to study pathological activity in living human tissue for pharmacoresistant partial epilepsy syndromes including temporal lobe epilepsies with hippocampal sclerosis, cortical dysplasias, epilepsies associated with tumors and developmental malformations. Slices of tissue from patients with these syndromes retain functional neuronal networks and may generate epileptic activities. The properties of cells in this tissue may not be greatly changed, but excitatory synaptic transmission is often enhanced and GABAergic inhibition is preserved. Typically epileptic activity is not generated spontaneously by the neocortex, whether dysplastic or not, but can be induced by convulsants. The initiation of ictal discharges in the neocortex depends on both GABAergic signaling and increased extracellular potassium. In contrast, a spontaneous interictal-like activity is generated by tissues from patients with temporal lobe epilepsies associated with hippocampal sclerosis. This activity is initiated, not in the hippocampus but in the subiculum, an output region, which projects to the entorhinal cortex. Interictal events seem to be triggered by GABAergic cells, which paradoxically excite about 20% of subicular pyramidal cells while simultaneously inhibiting the majority. Interictal discharges thus depend on both GABAergic and glutamatergic signaling. The depolarizing effects of GABA depend on a pathological elevation in levels of chloride in some subicular cells, similar to those of developmentally immature cells. Such defect is caused by a perturbed expression of the cotransporters regulating intracellular chloride concentration, the importer NKCC1 and the extruder KCC2. Blockade of NKCC1 actions by the diuretic bumetanide restores intracellular chloride and thus hyperpolarizing GABAergic actions and consequently suppressing interictal activity.

[Migration of a ventriculoperitoneal shunt in the liver: A rare complication]

We report on a case of migration inside the liver of the distal end of a ventriculoperitoneal shunt catheter in an adult patient. A simple laparotomy permitted the surgical removal with no haemorrhagic complication. We discuss the other cases reported in the literature and we outline the need to perform an abdominal CT scan in patients carrying a VP shunt with digestive symptoms.

[Spontaneous resorption of thoracic calcified disc herniation: Report of two cases and review of the literature]

We report on two cases of spontaneous resorption of a calcified thoracic hernia. This phenomenom is widely recognised in lumbar and cervical hernia, but is exceptional at the thoracic level. The potential mechanisms underlying this resorption are discussed trough a review of the literature. We think this could be another argument for a "wait and watch" period before a surgical decision in the patients who have few symptoms.