Utility of optical coherence tomography in the evaluation of sellar and parasellar mass lesions

Recent advances in the use of optical coherence tomography in neuro-ophthalmology: A review

Optical coherence tomography (OCT) is an in vivo imaging modality that provides non-invasive, high resolution and fast cross-sectional images of the optic nerve head, retina and choroid. OCT angiography (OCTA) is an emerging tool. It is a non-invasive, dye-free imaging approach of visualising the microvasculature of the retina and choroid by employing motion contrast imaging for blood flow detection and is gradually receiving attention for its potential roles in various neuro-ophthalmic and retinal conditions. We will review the clinical utility of the OCT in the management of various common neuro-ophthalmic and neurological disorders. We also review some of the OCTA research findings in these conditions. Finally, we will discuss the limitations of OCT as well as introduce other emerging technologies.

Retinal nerve fiber layer thickness and its correlation with visual symptoms and radiological features in pituitary macroadenoma

Objective

The aim of the study was to evaluate the association of the thickness of retinal nerve fiber layer (RNFL) with (i) visual symptoms and (ii) suprasellar extension defined by magnetic resonance imaging (MRI) in patients with pituitary macroadenoma.

Materials and Methods

RNFL thickness of 50 consecutive patients operated for pituitary macroadenoma between July 2019 and April 2021 were compared with standard visual examination findings and MRI measurements such as optic chiasm height, distance between the optic chiasm and adenoma, suprasellar extension, and chiasmal lift.

Results

The study group included 100 eyes of 50 patients operated for pituitary adenomas with suprasellar extension. RNFL thinning predominantly involved the nasal (84.26 ± 16.43 μm) and temporal quadrants (70.72 ± 14.80 μm) and correlated well with the visual field deficit (P < 0.001). Patients with moderate-to-severe deficit in visual acuity had a mean RNFL thickness <85 μm and patients with severe disc pallor had extremely thin RNFLs (<70 μm). Suprasellar extension defined as Wilsons Grade C, D, and E and Fujimotos Grades 3 and 4 were significantly associated with thin RNFLs <85 μm (P < 0.01). Chiasmal lift more than 1 cm and tumor chiasm distance of <0.5 mm were associated with thin RNFL (P < 0.002).

Conclusion

RNFL thinning correlates directly with the severity of visual deficits in patients with pituitary adenoma. Wilsons Grade D and E, Fujimoto Grade 3 and 4, chiasmal lift more than 1 cm, and chiasm tumor distance <0.5 mm are strong predictors of RNFL thinning and poor vision. Pituitary macro adenoma and other suprasellar tumors need to be excluded in patients with preserved vision but having obvious RNFL thinning.

The presenting visual symptoms of optic chiasmal disease

Recognising optic chiasmal disease early is important in order to avoid irreversible visual loss and the potential risk of mortality for patients. Yet, there is frequently a delay in the initial diagnosis. Whilst the signs of optic chiasmal disease, particularly the perimetric findings, are well documented in the recent literature, the symptoms have been less well reported. Whilst some patients with optic chiasmal disease will be asymptomatic, many will complain of visual symptoms including symptomatic field defects, problems with central vision, difficulty with near tasks, binocular visual disturbances, colour vision disturbances, photophobia, phosphenes, glare, and rarely, oscillopsia and visual hallucinations. Others may have headache or the severe and sudden visual symptoms associated with pituitary apoplexy. The visual symptoms may be vague or non-specific, even when there are significant bitemporal visual field defects. We aim in this review to describe the presenting visual symptoms of optic chiasmal disease, and to illustrate these with selected qualitative descriptions from the literature. Our hope is that this will aid clinicians in eliciting a careful history of the sometimes subtle symptoms that may be present.

Predictive value of retinal nerve fibre layer thickness for postoperative visual improvement in patients with pituitary macroadenoma

Objective

To determine the usefulness of retinal nerve fibre layer (RNFL) thickness and a reliable cut-off value that can predict postoperative visual function improvement in patients with pituitary macroadenoma.

Methods and Analysis

This was a prospective observational study. Preoperative optical coherence tomography of the RNFL was performed in patients with pituitary macroadenoma. Postoperative visual function changes (acuity and visual fields) were identified using predefined criteria. Receiver operating characteristic curves were constructed for RNFL values to define the ideal cut-off value that predicted improvement. Other variables including preoperative visual acuity, mean deviation, visual field index and tumour volume were also analysed.

Results

Twenty-nine eligible subjects (58 eyes) were recruited. The mean (±SD) age was 43.9 (±12.85) years and 65.5% were male. The mean (±SE) follow-up duration was 20.8 (±6.42) months. RNFL thickness was significantly thinner in eyes with visual dysfunction and optic disc pallor. Better preoperative logarithmic minimum angle of resolution (logMAR) visual acuity, higher RNFL thickness and smaller tumour volume were associated with postoperative visual field improvement on univariate analysis; however, only mean RNFL thickness had significant association on multivariate analysis. None of the preoperative variables showed significant association with improvement in visual acuity. The best cut-off of mean RNFL thickness for visual field improvement was estimated at 81 μm with 73.1% sensitivity and 62.5% specificity.

Conclusion

Preoperative RNFL thickness can be an objective predictor of visual field outcomes in patients undergoing surgery for pituitary macroadenomas, with moderate sensitivity and specificity. It is, however, not a good predictor of visual acuity outcome.

The use of optical coherence tomography angiography in patients with chiasmal compression (literature review)

Optical coherence tomography (OCT) is currently the leading method for the observation and evaluation of microstructural changes in the retina in vivo. In recent years, OCT has been used in clinical practice to monitor the progression of compressive optic neuropathy in patients with chiasmal-sellar region neoplasms. The results obtained in the course of the studies opened up new opportunities for studying the pathogenesis of the development of compressive optic neuropathy in patients of this group. The advent of OCT-angiography (OCTA), developed on the basis of OCT, made it possible to study changes in the blood flow of the radial peripapillary capillary network, superficial and deep capillary plexuses, which opens up many opportunities for further research into the pathogenesis of visual impairment in this group of patients, prognosis of the development of the disease, and selection optimal terms of treatment. The literature review presents and analyzes the currently available results of the use of OCTA in patients with chiasmal compression.

Structural and functional differentiation between compressive and glaucomatous optic neuropathy

Clinical diagnoses of slow, progressive, painless visual losses with various degrees of visual field (VF) losses and disc atrophy are often confused between suprasellar compressive optic neuropathy (CON) and open-angle glaucomatous optic neuropathy (GON). We plotted the thickness of the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) against the mean deviation (MD) of the VF of 34 eyes of CON at diagnosis, 30 eyes of CON after therapy, 29 eyes of GON, and 60 eyes of healthy controls in a cross-sectional investigation. At diagnosis, a disproportionally early pattern of structural thinning compared with the corresponding VF losses was unique to CON. GON- and CON-specific thinning parameters were generally useful in differentiating GON and CON from moderate to severe MD losses, but early MD losses (0 to - 6 dB) overlapped with GON in a CON-stage specific manner. GON-specific thinning parameters, RNFL in the inferior sector, and inferior to temporal macular GCIPL ratio showed overlap with posttreatment CON in the early MD losses with AUCs of 0.916 (95% CI 0.860-0.971; P < 0.001) and 0.890 (95% CI 0.811-0.968; P < 0.001), respectively. In comparison, CON-specific thinning parameters, superonasal, and inferonasal GCIPL showed overlap with CON at diagnosis for early MD losses. Overall, the nasal-to-temporal macular GCIPL ratio showed good discrimination between CON and GON throughout the MD range, with an AUC of 0.923 (95% CI 0.870-0.976; P < 0.001). Comparing GON with all stages of CON, the cut-point of 0.95 showed the lower nasal-to-temporal GCIPL ratio had a sensitivity of 72% and specificity of 90% for CON. However, the cut-point of 1.10 showed the superior-to-inferior GCIPL ratio had a sensitivity of 60% and specificity of 98% for GON.

Retinal Microvascular Alterations Detected by Optical Coherence Tomography Angiography in Nonfunctioning Pituitary Adenomas

Purpose

Visual impairment assessment plays a significant role in diagnosis and clinical decisions in nonfunctioning pituitary adenoma (NFPA). Retinal microvascular alterations may potentially reflect the visual impairment. The purpose of this study was to evaluate fundus microvascular alterations in patients with NFPA.

Methods

Comparisons of visual field, retinal structure, and microcirculation were conducted between patients with NFPA and age- and sex-matched healthy controls. Multivariate regression modeling was used to assess the relationship between symptom duration, sellar mass size, and fundus vessel density (VD) of patients. Receiver operating characteristic (ROC) curves were depicted to determine the diagnostic performance of significant parameters to discriminate eyes with NFPA from healthy eyes.

Results

Forty eyes of patients and 40 eyes of healthy individuals were enrolled. Compared to healthy controls, patients with NFPA had a larger foveal avascular zone area and thinner ganglion cell complex thickness. The VDs of patients presented an obvious decrease in radial peripapillary capillary (RPC) and an increase in the deep capillary plexus segment of the perifoveal area. The peripapillary VDs of patients were significantly related to sellar mass size. The area under the ROC curve of VD in the RPC segment of the temporo-inferior sector was the largest (0.801; 95% confidence interval, 0.70–0.90; P < 0.001).

Conclusions

The fundus of patients with NFPA demonstrated significant and characteristic microvascular impairments. The VDs were also significantly associated with sellar mass size.

Translational Relevance

Retinal microvascular alterations detected by optical coherence tomography angiography are characteristic and related to sellar mass size, which may provide information that facilitates the diagnosis of NFPA.

How do intracranial tumors associated with visual pathways affect quadrant and sectoral based optical coherence tomography measurements: The effect of intracranial tumors on RNFL and GC-IPL thickness

AIM

To investigate the quantitative sectoral and regional changes of retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL) thickness in different types of intracranial tumors associated with visual pathways.

METHODS

This comparative retrospective study included 58 eyes of 30 patients with intracranial tumors and the data of 62 eyes of 31 healthy subjects. The RNFL and GCIPL thicknesses were analyzed using spectral-domain optical coherence tomography (OCT). The tumors were classified into ones that affect pre-geniculate and post-geniculate pathway.

RESULTS

The mean RNFL thickness in temporal quadrant was significantly thinner in eyes with intracranial tumors affecting the pre-geniculate optic pathway compared to controls (p = 0.04). In contrast, the mean superior quadrant RNFL thickness was significantly thicker in eyes with brain tumors associated with post-geniculate optic pathway (p = 0.01). The mean GC-IPL thicknesses of the inner ring superotemporal, superonasal, inferotemporal and inferionasal sectors and outer ring superonasal and inferonasal sectors were significantly thinner in eyes with intracranial tumors affecting the pre-geniculate optic pathway compared to control eyes (p = 0.02, p = 0.001, p = 0.02, p = 0.003, p = 0.008 and p = 0.03 respectively).

CONCLUSION

The results of this study showed that significant changes can be seen in the different RNFL quadrants and GC-IPL sectors in eyes with intracranial tumors affecting pre-geniculate or post-geniculate optic pathway. OCT is a very useful imaging technique to quantify these structural changes which take place during the neurodegeneration process of visual pathways in intracranial tumors.

Recent advances and future directions on the use of optical coherence tomography in neuro-ophthalmology

Optical coherence tomography (OCT) is a noninvasive imaging technique used to qualitatively and quantitatively analyze various layers of the retina. OCT of the retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) is particularly useful in neuro-ophthalmology for the evaluation of patients with optic neuropathies and retrochiasmal visual pathway disorders. OCT allows for an objective quantification of edema and atrophy of the RNFL and GCIPL, which may be evident before obvious clinical signs and visual dysfunction develop. Enhanced depth imaging OCT allows for visualization of deep structures of the optic nerve and has emerged as the gold standard for the detection of optic disc drusen. In the evaluation of compressive optic neuropathies, OCT RNFL and GCIPL thicknesses have been established as the most important visual prognostic factor. There is increasing evidence that inclusion of OCT as part of the diagnostic criteria for multiple sclerosis (MS) increases its sensitivity. Moreover, OCT of the RNFL and GCIPL may be helpful in the early detection and monitoring the treatment of conditions such as MS and Alzheimer's disease. OCT is an important aspect of the neuro-ophthalmologic assessment and its use is likely to increase moving forward.

Functional Prognostic value of optical coherence tomography in optic chiasmal decompression: A preliminary study

PURPOSE

To assess the predictive value for functional recovery of Ganglion Cell Complex Layer (GCC) and Retinal Nerve Fiber Layer (RNFL) measurements obtained by Optical Coherence Tomography (OCT) in patients undergoing chiasmal decompression and to define potential OCT thresholds for visual recovery.

METHODS

We measured preoperative GCC and RNFL thickness in patients with a sellar and/or perisellar tumor compressing the optic chiasm. Visual recovery was defined as recovery of mean deviation (MD) and pattern standard deviation (PSD) using Humphrey visual field testing after 12 successful decompressions (24 eyes). Receiver operating characteristic curve (ROC) analysis was used to identify the best thresholds.

RESULTS

Robust global and focal OCT thresholds were found. Superior GCC≥63μm had the best functional prognostic value (AUC=1) for visual improvement. Mean GCC ≥ 67μm and mean RNFL≥75μm also had excellent predictive values (AUC>0.9).

CONCLUSION

In this preliminary study, significant preoperative OCT thresholds for early visual recovery after chiasmal decompression were identified, mainly regarding GCC measurements. Further studies on larger cohorts with closely scheduled follow-up could refine our results.

Optical coherence tomography significance in managing complex neurofibromatosis 2-related papilledema: Report of a case

This case describes the strong utility of optical coherence tomography in multidisciplinary management of a complex case of type 2 neurofibromatosis.

Multidisciplinary protocol of preoperative and surgical management of patients with pituitary tumors candidates to pituitary surgery

The optimal planning of preoperative diagnosis, management and treatment of pituitary tumors (PT) candidates to pituitary surgery (PS) requires a multidisciplinary approach involving a team of endocrinologists, neurosurgeons, ENT, neuro-ophthalmologists and neuroradiologists with experience in pituitary diseases. Such teams improve surgical results, minimize complications and facilitate their correct treatment if occurring, and optimize the hormonal, ophthalmological and radiological preoperative and follow-up evaluation. We have developed a clinical practice protocol for patients with PT who are candidates to PS based on the most recent national and international guidelines and the relevant literature regarding PT published in the last years. The protocol has been elaborated by a multidisciplinary team of a Spanish Pituitary Tumor Center of Excellence (PTCE) that includes at least one neurosurgeon, ENT, neuroradiologist, neuro-ophthalmologist, endocrine pathologist and endocrinologist specialized in pituitary diseases. We elaborated this guideline with the aim of sharing our experience with other centers involved in the perioperative and surgical management of PT thereby facilitating the management of patients undergoing PS.

Clinical efficacy of optical coherence tomography in sellar mass lesions: a meta-analysis

PURPOSE

Although optical coherence tomography (OCT) of the eyes has been studied to detect and monitor sellar masses, there is no recommendation for selecting the most effective measurement of OCT in clinical practice. Thus, we conducted a meta-analysis to examine the efficacy of OCT in sellar mass lesions.

METHODS

We conducted a literature search in PubMed and EMBASE through April 26, 2020. The primary outcomes were the thickness of the peripapillary retinal nerve fiber layer (pRNFL) and the macular ganglion cell complex (mGCC). The secondary outcomes included the thickness of the macular ganglion cell and inner plexiform layer (mGCIPL) and macular thickness. Random-effects models were used in all meta-analyses. Additionally, we conducted meta-regressions and subgroup analyses.

RESULTS

We included 22 studies, involving 1347 eyes of patients and 1198 eyes of controls. When compared with the control group, the reductions in pRNFL, mGCC and macular thickness in the patient group were significantly different, whereas significant thinning of the mGCIPL was restricted to the nasal hemiretina. Furthermore, we found that before visual field (VF) defects occurred, significant thinning of the pRNFL and mGCC thickness could be detected by OCT. The change in OCT parameters also showed different patterns in different types of pituitary adenomas.

CONCLUSIONS

Sellar mass lesions were associated with the changes in OCT measurements. The characteristic patterns of the OCT parameters may refine the diagnostic accuracy. Moreover, the alterations of OCT metrics before VF defects indicate the efficacy of OCT in early detection. Different types of pituitary adenomas may vary in OCT measurements, and their specific features warrant further research efforts.

Early vascular modifications after endoscopic endonasal pituitary surgery: The role of OCT-angiography

Purpose

The aim of the present study is to analyze the changes in retinal vessel density (VD), using Optical Coherence Tomography Angiography (OCT-A), in patients that received endoscopic endonasal approach for the removal of an intra-suprasellar pituitary adenoma compressing optic chiasm.

Methods

We evaluated the VD in Superficial Capillary Plexus (SCP), Deep Capillary Plexus (DCP), Radial Peripapillary Capillary (RPC) and the Foveal Avascular Zone (FAZ) area in a series of fourteen patients (7 males, 7 females, mean age 56 ± 13 years), as compared to healthy controls. We also detected the structural Spectral Domain (SD)-OCT parameters: Ganglion Cell Complex (GCC), Retinal Nerve Fiber Layer (RNFL), visual field parameters (Mean Deviation, Pattern Standard Deviation) and Best Corrected Visual Acuity (BCVA). These measurements were performed prior than surgery and 48 hours after.

Results

The patients showed a significant decrease in VD of the macular and papillary regions, a significant increase in FAZ area, a significant impairment in SD-OCT, VF parameters and BCVA respect to 14 eyes of 14 healthy controls (p<0.05), at pre-op evaluation. In patients group the VD in SCP, DCP and RPC increased after surgery respect to baseline but the difference turned to be out statistically significant only in RPC (p = 0.003). Also the BCVA (p = 0.040) and the Mean Deviation at visual field (p = 0.015) significantly improved after surgery. While there was a reduction in structural OCT parameters but it was statistically significant only in GCC (p = 0.039). A positive correlation was found between the preoperative VD of the RPC, Mean Deviation, BCVA and the postoperative Mean Deviation (r = 0.426 p = 0.027; r = 0.624 p = 0.001; r = 0.515 p = 0.006).

Conclusion

OCT-A allows to detect the early changes occurring within 48 hours after surgery showing that the improvement in retinal vessel density could occur before the recovery of the structural OCT parameters and can be a positive predictive factor for the functional recovery.

Chronic chiasmal compression and persistent visual field defect without detectable changes in optical coherence tomography of the macular ganglion cell complex

Purpose

Optical coherence tomography (OCT) of the retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) are important in the ophthalmological evaluation of patients with sellar masses. Changes in OCT of the RNFL and macular GCC often precede visual field changes in patients with chronic chiasmal compression. OCT of the macular GCC has been shown to have better correlation with visual function and allow for even earlier detection of compression of the anterior visual pathways. We present a case of a chronic visual field defect from a pituitary adenoma with largely normal OCT parameters and only subtle changes in OCT of the RNFL and no perceptible changes in OCT of the macular GCC.

Observations

A 32-year-old man presented with a four-month history of decreased vision in his left eye and was found to have a monocular temporal visual field defect from a pituitary adenoma. OCT of the RNFL showed only a subtle change in that the nasal quadrant was mildly reduced and the optic nerve did not follow the ISNT rule. There was no asymmetry, deviation from normal parameters or differences in the nasal and temporal sextants on OCT of the macular GCC. This remained stable after testing two months later and a worsening visual field defect. He was found to have an elevated prolactinoma and after initiation of cabergoline, his visual field defect rapidly resolved within a few days.

Conclusions and Importance

OCT RNFL and macular GCC may have parameters in the normal range in patients with chronic chiasmal compression, emphasizing the importance of both anatomical and psychophysical testing. OCT of the RNFL may show these changes earlier than OCT macular GCC and both should be performed for the pre-treatment evaluation of patients with sellar masses. Preserved RNFL and macular GCC thickness confer a good prognosis as demonstrated in this case with rapid resolution of visual changes after medical treatment.