Gliomas del tronco encefálico

A multi-task generative model for simultaneous post-contrast MR image synthesis and brainstem glioma segmentation

OBJECTIVES

This study aims to generate post-contrast MR images reducing the exposure of gadolinium-based contrast agents (GBCAs) for brainstem glioma (BSG) detection, simultaneously delineating the BSG lesion, and providing high-resolution contrast information.

METHODS

A retrospective cohort of 30 patients diagnosed with brainstem glioma was included. Multi-contrast images, including pre-contrast T1 weighted (pre-T1w), T2 weighted (T2w), arterial spin labeling (ASL) and post-contrast T1w images, were collected. A multi-task generative model was developed to synthesize post-contrast T1w images and simultaneously segment BSG masks from the multi-contrast inputs. Performance evaluation was conducted using peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), and mean absolute error (MAE) metrics. A perceptual study was also undertaken to assess diagnostic quality.

RESULTS

The proposed model achieved SSIM of 0.86 ± 0.04, PSNR of 26.33 ± 0.05 and MAE of 57.20 ± 20.50 for post-contrast T1w image synthesis. Automated delineation of the BSG lesions achieved Dice similarity coefficient (DSC) score of 0.88 ± 0.27.

CONCLUSIONS

The proposed model can synthesize high-quality post-contrast T1w images and accurately segment the BSG region, yielding satisfactory DSC scores.

CLINICAL RELEVANCE STATEMENT

The synthesized post-contrast MR image presented in this study has the potential to reduce the usage of gadolinium-based contrast agents, which may pose risks to patients. Moreover, the automated segmentation method proposed in this paper aids radiologists in accurately identifying the brainstem glioma lesion, facilitating the diagnostic process.

The importance of organic screening, regarding a clinical case

INTRODUCTION

Before cataloguing a morbid process as a "mental disorder", it is essential to bear in mind the importance of early diagnosis of causes of non-psychiatric origin for a possible clinical presentation. For this reason, we will try to reflect this fact, which it seems necessary to remember even though it is well known, since it can be overlooked in emergency situations in the hospital setting, with the consequences derived from an incomplete diagnosis and with the potential life-threatening risk for the patient.

CASE PRESENTATION

A 13-year-old female adolescent, who presented an acute clinical picture suggestive of dissociative disorder. She required hospital admission for diagnostic-therapeutic clarification, and neuroimaging findings led to an initial diagnosis of a neoplastic lesion in the brain stem and, finally, as ischaemic lesion of vasculitic origin in said location.

DISCUSSION

A differential diagnosis was proposed through the different psychic and non-psychic aetiologies of the clinical picture, but the intervention of the hospital's paediatric service was necessary for orientation and definitive affiliation, given the suspicion of non-psychiatric illness after a torpid evolution in spite of psychotherapeutic and psychopharmacological interventions.

CONCLUSIONS

Through the presentation and review of a clinical case that happened in our hospital, we must insist on an adequate comprehensive approach to the patient, especially with the child-adolescent population, when faced with an acute clinical presentation and without previous studies at a relevant physical level.

Role of neuronavigation in the surgical management of brainstem gliomas

Objective

NeuroNavigation (NN) is a widely used intraoperative imaging guidance technique in neurosurgical operations; however, its value in brainstem glioma (BSG) surgery is inadequately reported and lacks objective proof. This study aims to investigate the applicational value of NN in BSG surgery.

Method

A retrospective analysis was performed on 155 patients with brainstem gliomas who received craniotomy from May 2019 to January 2022 at Beijing Tiantan Hospital. Eighty-four (54.2%) patients received surgery with NN. Preoperative and postoperative cranial nerve dysfunctions, muscle strength, and Karnofsky (KPS) were evaluated. Patients' radiological features, tumor volume, and extent of resection (EOR) were obtained from conventional MRI data. Patients' follow-up data were also collected. Comparative analyses on these variables were made between the NN group and the non-NN group.

Result

The usage of NN is independently related to a higher EOR in diffuse intrinsic pontine glioma (DIPG) (p=0.005) and non-DIPG group (p<0.001). It was observed that fewer patients in the NN group suffered from deterioration of KPS (p=0.032) and cranial nerve function (p=0.017) in non-DIPG group, and deterioration of muscle strength (p=0.040) and cranial nerve function (p=0.038) in DIPG group. Moreover, the usage of NN is an independent protective factor for the deterioration of KPS (p=0.04) and cranial nerve function (p=0.026) in non-DIPG patients and the deterioration of muscle strength (p=0.009) in DIPG patients. Furthermore, higher EOR subgroups were found to be independently related to better prognoses in DIPG patients (p=0.008).

Conclusion

NN has significant value in BSG surgery. With the assistance of NN, BSG surgery achieved higher EOR without deteriorating patients' functions. In addition, DIPG patients may benefit from the appropriate increase of EOR.

The importance of organic screening, regarding a clinical case

INTRODUCTION

Before cataloguing a morbid process as a "mental disorder", it is essential to bear in mind the importance of early diagnosis of causes of non-psychiatric origin for a possible clinical presentation. For this reason, we will try to reflect this fact, which it seems necessary to remember even though it is well known, since it can be overlooked in emergency situations in the hospital setting, with the consequences derived from an incomplete diagnosis and with the potential life-threatening risk for the patient.

CASE PRESENTATION

A 13-year-old female adolescent, who presented an acute clinical picture suggestive of dissociative disorder. She required hospital admission for diagnostic-therapeutic clarification, and neuroimaging findings led to an initial diagnosis of a neoplastic lesion in the brain stem and, finally, as ischaemic lesion of vasculitic origin in said location.

DISCUSSION

A differential diagnosis was proposed through the different psychic and nonpsychic aetiologies of the clinical picture, being the intervention of the hospital's paediatric service necessary for orientation and definitive affiliation, given the suspicion of non-psychiatric illness after a torpid evolution in spite of psychotherapeutic and psychopharmacological interventions.

CONCLUSIONS

Through the presentation and review of a clinical case that happened in our hospital, we must insist on an adequate comprehensive approach to the patient, especially with the child-adolescent population, when faced with an acute clinical presentation and without previous studies at a relevant physical level.

Brainstem gliomas

Historically, brainstem gliomas have been considered as a single entity. Since the introduction of magnetic resonance (MR) imaging in the late 1980s, these tumors are now regarded as a heterogeneous group of neoplasms with different age of onset, clinical and radiologic presentation, and varying behavior and natural history. This article describes the different subtypes of brainstem gliomas in children and adults. We focus on recent advances in MR such as MR spectroscopy, MR perfusion, and diffusion tensor imaging that often strongly suggest the histopathologic diagnosis of the lesion.

Brainstem oligodendroglioma in a puppy

A 5 mo old male golden retriever presented for evaluation of an acute onset, progressive neurologic disease. Although computed tomography (CT) was unremarkable, MRI identified an ill-defined mass located in the medulla, which was considered likely responsible for the clinical signs. The imaging features closely resembled the classic features of human brainstem gliomas in the pediatric population. Histopathologic examination confirmed the lesion to be an anaplastic oligodendroglioma.

Exophytic giant cell glioblastoma of the medulla oblongata

Giant cell glioblastoma is a rare variant within the spectrum of glioblastoma multiforme (GBM) tumors. A giant cell glioblastoma may be associated with a better prognosis than the common type of GBM after combined treatment involving tumor resection and radiochemotherapy. A giant cell glioblastoma may occur at various sites in the brain and spinal cord. To the authors' knowledge, this type of tumor has not been previously reported as arising as an exophytic tumor from the medulla oblongata. The authors report on a 40-year-old man who presented with a large tumor located in the caudal fourth ventricle. The tumor was removed completely and the patient underwent percutaneous radiotherapy with 60 Gy and concomitant chemotherapy with temozolomide. Histopathological examination of the tumor revealed the typical features of a giant cell glioblastoma. At the 2-year follow-up the patient was doing well and showed no signs of tumor recurrence. It is important to identify variants of GBM because they may predict favorable long-term outcome, even when they arise from the caudal brainstem.