Preoperative volume of the optic chiasm is an easily obtained predictor for visual recovery of pituitary adenoma patients following endoscopic endonasal transsphenoidal surgery: a cohort study

BACKGROUND

Predicting the postoperative visual outcome of pituitary adenoma patients is important but remains challenging. This study aimed to identify a novel prognostic predictor which can be automatically obtained from routine MRI using a deep learning approach.

MATERIALS AND METHODS

A total of 220 pituitary adenoma patients were prospectively enrolled and stratified into the recovery and nonrecovery groups according to the visual outcome at 6 months after endoscopic endonasal transsphenoidal surgery. The optic chiasm was manually segmented on preoperative coronal T2WI, and its morphometric parameters were measured, including suprasellar extension distance, chiasmal thickness, and chiasmal volume. Univariate and multivariate analyses were conducted on clinical and morphometric parameters to identify predictors for visual recovery. Additionally, a deep learning model for automated segmentation and volumetric measurement of optic chiasm was developed with nnU-Net architecture and evaluated in a multicenter data set covering 1026 pituitary adenoma patients from four institutions.

RESULTS

Larger preoperative chiasmal volume was significantly associated with better visual outcomes ( P =0.001). Multivariate logistic regression suggested it could be taken as the independent predictor for visual recovery (odds ratio=2.838, P <0.001). The auto-segmentation model represented good performances and generalizability in internal (Dice=0.813) and three independent external test sets (Dice=0.786, 0.818, and 0.808, respectively). Moreover, the model achieved accurate volumetric evaluation of the optic chiasm with an intraclass correlation coefficient of more than 0.83 in both internal and external test sets.

CONCLUSION

The preoperative volume of the optic chiasm could be utilized as the prognostic predictor for visual recovery of pituitary adenoma patients after surgery. Moreover, the proposed deep learning-based model allowed for automated segmentation and volumetric measurement of the optic chiasm on routine MRI.

Transient Visual Obscurations Without Papilloedema as the Heralding Symptom of Chiasmal Compression

Transient visual obscurations (TVOs) represent brief ischaemic events of the optic nerve. These most commonly occur in the setting of raised intracranial pressure or more localised aetiologies within the orbit that result in decreased perfusion pressure. Transient vision loss has rarely been associated with pituitary tumours or optic chiasm compression, but details are lacking. We describe classic TVOs that completely resolved following resection of a pituitary macroadenoma causing chiasmal compression with a relatively normal eye examination. Clinicians should consider neuro-imaging in patients with TVOs and a normal evaluation.

SD-OCT parameters and visual field defect in chiasmal compression and the diagnostic value of neural network model

PURPOSE

To evaluate the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) measurements using spectral domain optical coherence tomography (SD-OCT) in patients with chiasmal compression and analyze the diagnostic value of a neural network model.

METHODS

Forty-seven patients with chiasmal compressive disorder were recruited and divided into two groups depending on the visual field defect (perimetric; group 1 and preperimetric; group 2). Fifty-seven normal subjects were also recruited (group 3). Peripapillary RNFL and macular GCIPL were analyzed in each group. A multilayer perceptron was trained using a training dataset and derived a neural network model. The diagnostic performances were compared using the area under the receiver operating curve (AUROC) between each parameters and neural network model.

RESULTS

All macular GCIPL parameters, except inferotemporal GCIPL thickness, were thinner in group 1 than in group 2 and group 3, with barely any difference between group 2 and group 3 parameter values. The diagnostic power of the neural network model, minimum GCIPL, and inferonasal GCIPL were superior when compared with other parameters; the diagnostic values of these three parameters are not significantly different in discriminating the patients and normal control. However, the neural network exhibited the best diagnostic power in distinguishing group 2 and group 3.

CONCLUSION

Macular GCIPL was reduced in chiasmal compression patients with visual field defect which was not evident in the preperimetric state. Neural network model showed superior diagnostic value in discriminating the preperimetric patients from normal control. The results suggest that neural networks may be helpful in the early diagnosis of chiasmal compression.

Optical coherence tomography analysis of inner and outer retinal layers in eyes with chiasmal compression caused by suprasellar tumours

PURPOSE

To compare postoperative macular thickness measurements of inner and outer retinal layers in eyes of patients with chiasmal compression with or without visual field (VF) recovery and healthy controls using optical coherence tomography (OCT).

METHODS

Macular spectral-domain OCT has been used for the auto-segmentation of images obtained from 100 eyes affected with chiasmal compression compared with 100 healthy controls enrolled in this study. We have divided eyes with chiasmal compression into two groups: group 1 characterized by VF recovery after tumour excision and group 2 showing partial or no recovery of VF. The thickness of the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor layer (PRL), inner retinal layer (IRL) and outer retinal layer (ORL) was segmented. The correlation between macular RNFL (mRNFL) and functional parameters has been analysed.

RESULTS

Both groups 1 and 2 showed significant thinning of RNFL, GCL, IPL and IRL in all quadrants. However, no significant changes have been detected in PRL and ORL of patients in either group compared with healthy controls. A significant thickening was detected in INL and ONL of group 2 compared with healthy controls and group 1. Postoperative mRNFL thickness is significantly correlated with VF defects and visual acuity except temporal quadrant.

CONCLUSIONS

Eyes with chiasmal compression showed thinning of the inner retinal layers with thickening of the INL and ONL in patients with partial to no recovery of VF. The changes in retinal microstructures are well-correlated with functional recovery. Further studies are needed to reveal the clinical implications of these findings in patients with chiasmal compression.

Parafoveal and Peripapillary Perfusion Predict Visual Field Recovery in Chiasmal Compression due to Pituitary Tumors

Background: To evaluate the potential of vessel density alterations for predicting postoperative visual field (VF) improvement in chiasmal compression using optical coherence tomography angiography (OCT-A). Methods: The study investigated 57 eyes of 57 patients diagnosed with pituitary tumors and 42 eyes of 42 age and refractive error matched controls. All eyes with chiasmal compression for which preoperative optical coherence tomography (OCT) and OCT-A, and pre- and postoperative VF data were available. Preoperative vessel densities of superficial retinal capillary plexus (SRCP), deep retinal capillary plexus (DRCP), and radial peripapillary capillary (RPC) segment were utilized by OCT-A. Results: Preoperative peripapillary retinal nerve fiber layer and ganglion cell layer complex thickness and vessel densities of SRCP and RPC segments in eyes with chiasmal compression were significantly reduced compared with healthy controls (p < 0.001, p < 0.001, p = 0.007, and p = 0.020, respectively). In multivariate regression analysis, preoperative perimetric mean deviation (MD) (p = 0.002) and vessel density of SRCP (p = 0.025) were correlated significantly with postoperative perimetric MD. Spearman’s correlation analysis revealed significant correlations between preoperative MD on perimetry (r = 0.443, p = 0.001), vessel densities of SRCP (r = 0.288, p = 0.035) and RPC segment (r = 0.347, p = 0.009), and postoperative perimetric MD. Conclusions: Structural degeneration referred to as microvascular alterations measured by OCT-A and preoperative VF defects were associated with worse postoperative VF prognosis. Parafoveal and peripapillary vessel densities may serve as a sensitive, structural prognostic factors in the preoperative judgement of chiasmal compression.

Morphological and Functional Inner and Outer Retinal Layer Abnormalities in Eyes with Permanent Temporal Hemianopia from Chiasmal Compression

Purpose

The aims of this study are to compare optical coherence tomography (OCT)-measured macular retinal layers in eyes with permanent temporal hemianopia from chiasmal compression and control eyes; to compare regular and slow-flash multifocal electroretinography (mfERG) in patients and controls; and to assess the correlation between OCT, mfERG, and central visual field (SAP) data.

Methods

Forty-three eyes of 30 patients with permanent temporal hemianopia due to pituitary tumors who were previously submitted to chiasm decompression and 37 healthy eyes of 19 controls were submitted to macular spectral domain OCT, mfERG, and 10-2 SAP testing. After segmentation, the thickness of the macular retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer, and photoreceptor layer (PRL) was measured. Amplitudes and oscillatory potentials (OPs) were measured on regular and slow-flash mfERG, respectively, and expressed as the mean values per quadrant and hemifield.

Results

RNFL, GCL, and IPL thickness measurements were significantly reduced in all quadrants, whereas INL, OPL, and PRL thicknesses were significantly increased in the nasal quadrants in patients compared to those in controls. Significant correlations between OCT and 10-2 SAP measurements were positive for the RNFL, GCL, and IPL and negative for the INL, OPL, and PRL. OPs and mfERG N1 amplitudes were significantly reduced in the nasal hemiretina of patients. Significant correlations were found between OP and mfERG amplitudes for inner and outer nasal hemiretina OCT measurements, respectively.

Conclusion

Patients with permanent temporal hemianopia from previously treated chiasmal compression demonstrated significant thinning of the RNFL, GCL, IPL, and thickening of the INL, OPL, and PRL associated with reduced OP and mfERG N1 amplitudes, suggesting that axonal injury to the inner retina leads to secondary damage to the outer retina in this condition.

Predictive value of preoperative retinal nerve fiber layer thickness for postoperative visual recovery in patients with chiasmal compression

The aim of this study was to evaluate the predictive role of preoperative retinal nerve fiber layer (RNFL) thickness for postoperative visual recovery in patients with chiasmal compression through performing a meta-analysis. PubMed, EMBASE, Cochrane Library and China National Knowledge Infrastructure were searched for relevant studies. The study and patient characteristics were extracted. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to estimate the predictive value of RNFL thickness. Subgroup analyses were also performed. Four studies with 202 patients and 395 eyes were included. The pooled results showed that patients with normal RNFL thickness could achieve better visual recovery compared with those with thin RNFL with the OR of 15.61 (95% CI, 4.09-59.61). Significant heterogeneity was observed (I2 = 54.5%, P=0.086). Publication bias was not present. Normal preoperative RNFL thickness could predict better postoperative visual recovery than thin RNFL in patients with chiasmal compression.

The detection of macular analysis by SD-OCT for optic chiasmal compression neuropathy and nasotemporal overlap

PURPOSE

To assess the diagnostic performance of the macular parameters detected by spectral-domain optical coherence tomography (SD-OCT) in band atrophy (BA) eyes.

METHODS

Forty-nine BA eyes with permanent temporal hemianopia and 89 normal eyes were enrolled. Any patients who had nasal visual field loss were excluded. Each participant was imaged by three-dimensional (3D) OCT-2000, and 10 × 10 grids in the macula were automatically allocated. The thickness of the macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL)+ (GCL+inner plexiform layer [IPL]), and GCL++ (RNFL+GCL+IPL) in both nasal and temporal hemiretina was calculated and compared between the BA and normal eyes. The areas under the receiver operating characteristic curves (AUCs) in these parameters were compared between the nasal hemiretina and the temporal hemiretina.

RESULTS

All the parameters in the BA eyes were significantly thinner than those in the normal eyes. The AUCs for the mRNFL, GCL+, and GCL++ thickness in the nasal hemiretina were 0.890, 0.988, and 0.981, respectively. The parameters in the nasal hemiretina showed significantly higher AUCs than those parameters in the temporal hemiretina. In the temporal hemiretina, the damaged grids in the mRNFL were located in the arcuate areas in each hemifield.

CONCLUSIONS

The inner macular parameters in the nasal hemiretina exhibited high diagnostic abilities to detect BA. The GCL+ was more affected than mRNFL. The characteristic pattern of mRNFL and GCL+ thinning was implicated in the anatomical architecture regarding the nasotemporal overlap of the crossed and uncrossed fibers around the fovea. (www.umin.ac.jp/ctr number, UMIN000006900.).