The volume of tumor mass and visual field defect in patients with pituitary macroadenoma

A retrospective cohort study assessing geometrical parameters related to visual deterioration in pituitary macroadenoma

PURPOSE

We aim to identify specific parameters that will allow identification of those patients at greater risk of vision loss, specifically variables such as geometry, volume and size of the pituitary tumour.

METHODOLOGY

Volume measurements were made with both manual (using the formula width × height × length × 0.5) and video size, sub-voxel interpolation using Brainlab software. The shape of the tumour was divided into four categories, ovoid, dumbbell, pyramidal and other. Chiasmal compression was divided into central and lateral compression and the chiasm location was classified based on pre/post and normal fixed chiasm in relation to the tuberculum sella. We used a visual impairment score ranging from (0-100), which was then further subdivided in to four grades: Grade I - 0-25 (mild); Grade II - 26-50 (moderate); Grade III - 51-75 (severe); Grade IV - 76-100 (subtotal or complete).

RESULTS

Univariate analysis of variables related to vision loss found tumour volume, suprasellar growth and lateral chiasmal compression related to pre-operative vision loss. On multivariate regression analysis tumour volume and lateral chiasmal compression remained significant (p < 0.008). In relation to post-operative vision, univariate analysis indicated that variables such as giant macroadenoma, pre-operative visual impairment score and suprasellar growth were significant. Multivariate analysis showed pre-operative visual impairment and suprasellar growth as the only statistically significant variables.

CONCLUSION

Our ROC analysis suggests tumours with suprasellar extension 16 mm (sensitivity 85 %, specificity 67 %) in sagittal plane are more likely to result in moderate to severe grade vision loss (VIS grade ≥ 2).

Prognostic Factors for Invasiveness and Recurrence of Pituitary Adenomas: A Series of 94 Patients

(1) Background: The aim of the current study is to evaluate the immunohistochemical expression of Ki-67, CD-56, Cyclin-D1 and E-Cadherin in the tissues samples of pituitary adenomas (PAs) and its association with PAs clinical manifestation tumor size, invasiveness and the risk of recurrence. (2) Materials and Methods: Ninety-four patients who underwent endoscope transsphenoidal excision of PAs were included in our study. The immunohistochemical expression of the Cyclin-D1, CD-56, E-Cadherin and Ki-67 markers was analyzed in paraffin-embedded tissue samples. (3) Results: The expression of Cyclin-D1 and Ki-67 index levels was positively correlated with the size (p < 0.001, r = 0.56 and p < 0.001, r = 0.43, respectively), the recurrence (p < 0.001, r = 0.46 and p = 0.007 r = 0.3, respectively), the extrasellar extension (p < 0.001, r = 0.48 and p < 0.001, r = 0.4, respectively) and the cavernous sinus invasion of (p < 0.001, r = 0.39 and p < 0.001, r = 0.3, respectively). No correlation was found between CD-56 and E-Cadherin expression with the size, the invasiveness and the recurrence of PAs. (4) Conclusion: Cyclin-D1 and Ki-67 are promising immunohistochemical markers in predicting the invasive behavior and recurrence of PAs in contrast to E-Cadherin and CD-56 which did not seem to be associated with PAs behavior post-surgery. However, larger studies are required in order to establish their role in the routine evaluation of PAs.

Postoperative complications after endoscope-assisted transsphenoidal surgery for pituitary adenomas: a case series, systematic review, and meta-analysis of the literature

PURPOSE

Endoscope-assisted transsphenoidal surgery over the last few years has led to more radical excision of pituitary adenomas (PAs) with a low complication rate. Systematic registration of complications by experienced surgical teams could help to improve this technique while ameliorating the patients' quality of life.

MATERIALS AND METHODS

One hundred ten endoscopic procedures were performed in 94 patients with PAs (37 functional) by the same neurosurgical team of a tertiary center during the period 2014-2019. Post-surgical complications were analyzed and compared with data published during the last 5 years in the PubMed and Cochrane databases by performing a systematic review and meta-analysis of the literature.

RESULTS

The overall complication rate in our series was 23.4%. Diabetes insipidus (DI) and intraoperative cerebrospinal fluid (CSF) leakage were the commonest complications (12.8%), followed by postoperative hypopituitarism (9.2%) and hematoma (8.5%) during the follow-up of 2.15 ± 1.4 years. Syndrome of inappropriate antidiuretic hormone secretion, meningitis, deep vein thrombosis, and hyposmia were rare (< 3%). Postoperative hypopituitarism was significantly associated with incidence of hematoma. No statistically significant association was found between PAs Hardy and Knosp scale grading or between patients' characteristics with the occurrence of postoperative complications. Our meta-analysis including nine studies found no significant differences comparing the complications of endoscopic versus microscopic surgery.

CONCLUSION

The endoscopic approach is safe when performed by experienced surgical teams. CSF leakage and DI were the commonest complications in our series; however, confirmation by larger studies is required. Meta-analysis showed no statistically significant differences in complication rates comparing endoscopic versus microscopic surgery.

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.

Junctional Scotoma and Patterns of Visual Field Defects Produced by Lesions Involving the Optic Chiasm

BACKGROUND

Lesions of the optic chiasm (OC) typically produce bitemporal hemianopia (BTH) on visual field (VF) testing, whereas lesions located at the nasal optic nerve-chiasmal (ON-OC) junction have been proposed to produce junctional scotoma (JXS), a central defect in the ipsilateral eye with temporal field loss in the contralateral eye. In this study, we investigated whether the pattern of VF loss in patients with chiasmal compression predicted the appearance of the causative lesion on neuroimaging and described the clinical presentation of these patients with different types of VF defect.

METHODS

Retrospective chart review of patients seen in tertiary neuro-ophthalmology practice over 6 consecutive years with lesions abutting or displacing the OC was performed. Lesion size and location relative to the OC on neuroimaging was determined and correlated with VF defects as well as optical coherence tomography (OCT) of the peripapillary retinal nerve fiber layer and macular ganglion cell complex (GCC).

RESULTS

Fifty-three patients were enrolled. VFs demonstrated JXS (n = 18), BTH (n = 14), monocular VF defect (n = 4), and no VF defect (n = 17); 64.7% of cases with normal VFs had radiologic OC compression. Lesion volume was highest in the JXS group, and these patients also had the poorest presenting visual acuity. All patients with JXS showed involvement of the ON-OC junction; however, not all cases showed compression of the OC from the nasal direction (15 of 18), and 17 of 18 also showed compression of one or both prechiasmatic ONs. Compression of the ON-OC junction was also seen in 79% of BTH, 100% of monocular VF defect, and 59% of no VF defect cases. Fifty percent of patients with normal VFs already had thinning of the GCC on OCT. GCC thinning was most pronounced nasally in the BTH group, but diffuse bilateral thinning was found in 38% of cases compared with 60% of JXS. VFs improved in 6 of 6 patients with BTH but only in 5 of 8 JXS cases after treatment.

CONCLUSIONS

JXS is more often seen with larger lesions and when there is compression of both the prechiasmatic ON and ON-OC junction. These patients have worse presenting visual acuity and poorer outcomes. Not all patients with radiologic compression had VF defects, although 50% of patients with normal VFs had evidence of compression on the macular GCC analysis, emphasizing the importance of macular OCT in the evaluation of patients with lesions involving the OC.

Predictive value of OCT and MRI for postoperative visual recovery in patients with chiasmal compressive lesions

PURPOSE

We aimed to investigate the predictive value of retinal thickness measured by optical coherence tomography (OCT) and mass biometrics measured using magnetic resonance image (MRI) for visual recovery after surgery for removal of a mass compressing the optic chiasm.

METHODS

Consecutive patients who showed typical temporal visual field defect (VFD) with respect to the vertical meridian due to a chiasmal compressive mass and who underwent mass removal surgery were recruited. Ophthalmic examination was performed preoperatively and postoperatively. Retinal thickness was measured by the Cirrus OCT. The height and size of the mass and suprasellar extension (SSE) in both the sagittal and coronal planes were evaluated. Patients were divided into two groups based on the improvement in VFD (mean deviation [MD] change ≥ 5 dB: group R; others: group NR) and clinical characteristics were compared.

RESULTS

Fifteen patients were included in the study. Eight (53.3%) patients were allocated into group R and others (7 patients, 46.7%) into group NR. Age, sex, initial visual acuity, initial MD was not different between the two groups. The retinal thicknesses were not different while tumor height, volume, and both sagittal and coronal SSE were significantly different between the two groups. (p = 0.029, 0.014, <0.001, and <0.001, respectively) All MRI parameters showed significant predictive value for the degree of MD recovery.

CONCLUSION

MRI showed better predictive value than OCT in predicting postoperative VFD recovery in patients with temporal VFDs due to chiasmal compressive disorder.

The Radiologic Characteristics and Retinal Thickness Are Correlated With Visual Field Defect in Patients With a Pituitary Mass

BACKGROUND

Investigation of visual field defects (VFDs) is important to decide the treatment and to predict the prognosis in patients with a pituitary mass. The aim of this study was to evaluate the correlation among 2 diagnostic modalities-MRI and optical coherence tomography (OCT)-and VFDs.

METHODS

Consecutive patients who showed the presence of a pituitary mass on MRI and in whom ophthalmic examinations were performed were recruited. Height and volume of the mass, sagittal and coronal displacement of optic chiasm, and the direction of mass expansion were measured. Patients were divided into 2 groups according to the presence (VFD group) or absence of VFDs (no VFDs group [NVFD]). The correlation among MRI parameters, OCT parameters, and VFDs were examined, and the diagnostic values of MRI and OCT and the combined value of the 2 modalities were analyzed.

RESULTS

Forty-one patients were included. The greatest coefficients of determination were observed between the sagittal displacement and pattern standard deviation (PSD) (R2 = 0.3661, P < 0.001) and between the inferonasal ganglion cell-inner plexiform layer (GCIPL) and PSD (R2 = 0.4079, P < 0.001). The height and the size of the mass in the VFD group were significantly greater as 57% and 148%, respectively, and the VFD group had more severe chiasmal displacement both in the sagittal (165%) and in the coronal (178%) plane (large effect in all). All macular GCIPLs were thinner in the NVFD group (range 9%-26%, large effect), whereas only temporal (25%) and average (11%) values were among peripapillary retinal nerve fiber layers.

CONCLUSIONS

The highest correlations with the degree of the VFD were seen in the sagittal displacement of optic chiasm and the inferonasal GCIPL, and these parameters were correlated concurrently. Both modalities showed a good diagnostic value for discriminating VFDs.

Mouth-nose masks impair the visual field of healthy eyes

Background

Mouth-nose masks have been requested to prevent the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The aim of the present study was to investigate, if wearing a mouth-nose mask impairs the visual field function in normals.

Methods

Thirty eyes of 30 subjects were recruited for the present study. White-on-white perimetry (OCTOPUS 900; 90°) was done and sensitivity was analysed in 14 defined test points (P1-P14, inferior visual field) under 3 different test conditions while the subjects were wearing a mouth-nose mask: (I) 1.5 cm under the lower eyelid, nose clip not used (position_{1.5cm_no_clip}); (II) 1.5 cm under the lower eyelid, nose clip correctly positioned (position_{1.5cm_with_clip}); (III) 0.5 cm under the lower eyelid, nose clip correctly positioned (position_{0.5cm_with_clip}). All data were compared to sensitivity without wearing a mouth-nose mask (reference). Mean Δ was calculated, being the difference between the results of each test condition and reference, respectively.

Results

Sensitivity was significantly different between position_{1.5cm_no_clip} and reference at 10 test points (p<0.05). Sensitivity at test point P7 was significantly different between position_{1.5cm_with_clip} and position_{0.5cm_with_clip} compared to reference (p<0.001), respectively. Mean Δ increased while wearing a mask at P7: position_{1.5cm_with_clip} (-8.3 dB ± 7.3 dB) < position_{0.5cm_with_clip} (-11.3 dB ± 9.5 dB) < position_{1.5cm_no_clip} (-20.1 dB ± 7.6 dB).

Conclusion

Visual field function was observed to be significantly impaired in the inferior-nasal sector while persons were wearing a mouth-nose mask, especially when the nose clip was not correctly used.

Quantitative visual pathway abnormalities predict visual field defects in patients with pituitary adenomas: a diffusion spectrum imaging study

OBJECTIVES

This study was to investigate clinical applicability of diffusion spectrum imaging (DSI) for quantitative detection of visual pathway abnormalities to predict the degree of visual field defects (VFD) in patients with pituitary adenomas.

METHODS

Sixty-five patients with pituitary adenomas and 33 healthy controls underwent conventional MRI and DSI scanning that allowed high-angular-resolution fiber tracking. Optic chiasmal compression and VFD were confirmed in all patients via radiological and neuro-ophthalmological examinations. Quantitative assessments of chiasmal lift, VFD, and DSI parameters from the optic nerve, optic tract, and optic radiation were performed. Group comparisons and correlation analyses were conducted in patients and controls. Using the 5-fold cross-validation method, the support vector machine classifiers were constructed to predict the degree of visual defects.

RESULTS

The mean values of quantitative anisotropy and generalized fractional anisotropy in optic nerve and optic tract showed significant differences between patients and controls (p < 0.05). These parameters were also significantly correlated with the chiasmal lift distance and degree of visual defects (p < 0.05). All patients were divided into mild (n = 42) and severe (n = 23) VFD groups, using the mean deviation value of -8 dB as the threshold. The classifiers achieved an accuracy of 0.83, sensitivity of 0.78, and specificity of 0.86 to discriminate patients with mild and severe visual defects.

CONCLUSIONS

Using high-angular-resolution fiber tracking, DSI may provide quantitative information to detect visual pathway abnormalities and be a potential diagnostic tool for determining the degree of visual field defects in pituitary adenomas.

KEY POINTS

• Abnormal QA and GFA values of optic nerve and optic tract in adenoma patients • Close relationship between DSI parameters and VFD degree in adenoma patients • The classifiers achieved an accuracy of 0.83, sensitivity of 0.78, and specificity of 0.86 to discriminate patients with mild and severe VFD.

Ocular symptoms as the initial clinical manifestations in patients with extraocular tumors

Background

Due to the variety of clinical presentation, some tumors may be concealed and easily misdiagnosed, leading to delays in management. We report a series of patients who initially presented to an Ophthalmic Clinic with ocular symptoms and were subsequently diagnosed with extraocular tumors.

Methods

Patients who presented to the ophthalmic outpatient clinic at the Joint Shantou International Eye Center with ocular symptoms between April 2013 and December 2019 and were subsequently diagnosed with intracranial or systemic tumors were reviewed retrospectively. Clinical data, including ocular symptoms and signs, ophthalmic and systemic imaging examinations, and the results of tumor biopsies were collected and analyzed.

Results

Twenty-three patients were included in this study, of which 16 were female (69.6%) and 7 were male (30.4%). Chief complaints at the first visit included visual loss (n=20), proptosis (n=2), and diplopia (n=1). Ocular examination revealed disc pallor (n=8) and swelling (n=3), choroidal mass with or without chorioretinal detachment (n=5), and proptosis (n=2). Visual field (VF) examination was performed in 11 patients of which hemianopia (n=4) and non-specific field loss (n=7) were noted. Brain CT or MRI, together with histopathological findings from surgical biopsies confirmed the diagnosis of the intracranial tumors in 18 cases, including pituitary adenoma (n=7), meningioma (n=2), oligodendroglioma (n=1), sellar tumor (n=1), suprachiasmatic arteriovenous aneurysm (n=1), orbital glioma (n=1), multiple intracranial tumors (n=1), and sphenoid ossifying fibroma (n=1). Nasopharyngeal carcinoma (NPC) (n=3) was diagnosed with brain MRI and nasal endoscopy. Five patients were confirmed as choroidal metastasis secondary to lung cancer (n=3), hepatoma (n=1), and breast cancer (n=1).

Conclusions

Patients with extraocular tumors may present initially to an ophthalmologist with ocular symptoms. It is important to identify and appropriately manage these patients to avoid unnecessary delays in future treatment.

The Chiasmal Compression Index: An Integrative Assessment Tool for Visual Disturbances in Patients with Pituitary Macroadenomas

OBJECTIVE

Visual status is routinely evaluated by neuro-ophthalmologic examination and computerized visual field (VF) tests in patients with chiasmal compression secondary to pituitary macroadenoma. Currently, no relevant data exists to accurately quantify the extent of optic apparatus compromise to further guide clinical decision-making. We aimed to assess for a possible quantitative correlation between optic chiasm geometric properties on magnetic resonance imaging (MRI) and VF deficits.

METHODS

Visual assessments and concurrent MRI scans were retrospectively reviewed from patients treated for pituitary macroadenoma in a single medical institution. Chiasm width, chiasm minimal and maximal height, and chiasm angle were measured on MRI coronal plane images by 3 independent reviewers (for the sake of variability analysis). VF numerical summary parameters were also retrieved.

RESULTS

A total of 30 patients were included in the final analysis. Average VF index was 70% (±30), and averaged mean deviation was 10.0 db (±9). Chiasm angle and width (which together represents the bending and stretching of the chiasm by the upward directed compression; both of which demonstrated high inter- and intraobserver agreement) showed strong correlation with VF loss. Chiasmal compression index derived from those parameters showed even stronger correlation.

CONCLUSIONS

The strong correlation demonstrated by our results of this relatively simple radiologic measurement with VF status, despite the relatively small cohort, calls for further investigation in this promising direction, and may facilitate with basic assessment and clinical decision-making for patients with equivocal neuro-ophthalmologic evaluation, as well as with poor compliance.

Assessment of inner retina layers thickness values in eyes with pituitary tumours before visual field defects occur

BACKGROUND

The purpose of this study was to evaluate macula, retinal nerve layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL) and macular nerve fibre layer (mNFL) thickness in patients with pituitary tumours who has normal visual field (VF).

METHODS

Thirty-five eyes of 35 patients with pituitary tumours with normal VF and 41 eyes of 41-healthy subjects were underwent a complete ophthalmic examination. The spectral domain- optical coherence tomography (OCT) was used to measure macular and optic disc parameters. Layer-by-layer segmentation was done automatically by using the new software. Data analyses were performed by using SPSS for Windows, version 22.0.

RESULTS

Average of total macula thickness inner temporal (p: 0.006), outer temporal (p < 0.001), inner nasal (p: 0.03), outer nasal (<0.001) were significantly lower in pituitary tumour group than normal group. Average of RNFL (p:0.009), temporal (p: 0.001), superiotemporal (p:0.004) and inferiotemporal (p: 0.01) were significantly lower in pituitary tumour group than normal group. Average of central GCL (p: 0.01) and central NFL (p: 0.03) were significantly lower in pituitary tumour group than normal group. There was no statistically significant difference between the two groups in IPL averages.

CONCLUSIONS

Pituitary tumour patients with normal VF had reduced nasal and temporal section of the total macula, temporal RNFL, central mGCL and mNFL thicknesses, reflecting the corresponding to the anatomical substrate of the underlying pathology of chiasmal compression. This indicates that the presence of retinal thinning may be a sign of early detection of anterior visual pathway injury before VF loss becomes apparent.

Human visual skills for brain-computer interface use: a tutorial

Background and objectives: Many brain-computer interfaces (BCIs) for people with severe disabilities present stimuli in the visual modality with little consideration of the visual skills required for successful use. The primary objective of this tutorial is to present researchers and clinical professionals with basic information about the visual skills needed for functional use of visual BCIs, and to offer modifications that would render BCI technology more accessible for persons with vision impairments.Methods: First, we provide a background on BCIs that rely on a visual interface. We then describe the visual skills required for BCI technologies that are used for augmentative and alternative communication (AAC), as well as common eye conditions or impairments that can impact the user's performance. We summarize screening tools that can be administered by the non-eye care professional in a research or clinical setting, as well as the role of the eye care professional. Finally, we explore potential BCI design modifications to compensate for identified functional impairments. Information was generated from literature review and the clinical experience of vision experts.Results and conclusions: This in-depth description culminates in foundational information about visual skills and functional visual impairments that affect the design and use of visual interfaces for BCI technologies. The visual interface is a critical component of successful BCI systems. We can determine a BCI system for potential users with visual impairments and design BCI visual interfaces based on sound anatomical and physiological visual clinical science.Implications for RehabilitationAs brain-computer interfaces (BCIs) become possible access methods for people with severe motor impairments, it is critical that clinicians have a basic knowledge of the visual skills necessary for use of visual BCI interfaces.Rehabilitation providers must have a knowledge of objectively gathering information regarding a potential BCI user's functional visual skills.Rehabilitation providers must understand how to modify BCI visual interfaces for the potential user with visual impairments.Rehabilitation scientists should understand the visual demands of BCIs as they develop and evaluate these new access methods.

Quantitative assessment of secondary white matter injury in the visual pathway by pituitary adenomas: a multimodal study at 7-Tesla MRI

OBJECTIVE

The objective of this study was to investigate microstructural damage caused by pituitary macroadenomas by performing probabilistic tractography of the optic tracts and radiations using 7-T diffusion-weighted MRI (DWI). These imaging findings were correlated with neuro-ophthalmological results to assess the utility of ultra-high-field MRI for objective evaluation of damage to the anterior and posterior visual pathways.

METHODS

Probabilistic tractography employing 7-T DWI was used to reconstruct the optic tracts and radiations in 18 patients with adenomas and in 16 healthy volunteers. Optic chiasm compression was found in 66.7% of the patients and visual defects in 61.1%. Diffusion indices were calculated along the projections and correlated with tumor volumes and results from neuro-ophthalmological examinations. Primary visual cortical thicknesses were also assessed.

RESULTS

Fractional anisotropy was reduced by 21.9% in the optic tracts (p < 0.001) and 17.7% in the optic radiations (p < 0.001) in patients with adenomas. Patients showed an 8.5% increase in mean diffusivity of optic radiations compared with healthy controls (p < 0.001). Primary visual cortical thickness was reduced in adenoma patients. Diffusion indices of the visual pathway showed significant correlations with neuro-ophthalmological examination findings.

CONCLUSIONS

Imaging-based quantification of secondary neuronal damage from adenomas strongly correlated with neuro-ophthalmological findings. Diffusion characteristics enabled by ultra-high-field DWI may allow preoperative characterization of visual pathway damage in patients with chiasmatic compression and may inform prognosis for vision recoverability.

Using sellar region tumor's size as a predictor of psychophysical and electrophysiological perimetric visual losses: a logistic regression approach

BACKGROUND

Sellar region tumor growth represents an important cause of visual loss due to mechanical compression of the optic nerve apparatus. Many investigations have used non-invasive tools to evaluate the visual field consequences of this damage, and good associations have been reported between psychophysical and electrophysiological perimetries. Few reports have considered the tumor size as a predictor of visual field loss.

AIMS

In the present study, we evaluated the association between the visual perimetry measured by Humphrey visual field analyzer and multifocal visual evoked cortical potential (mfVECP) and the tumor size.

METHODS

Our sample was composed of 14 patients diagnosed with sellar tumors by magnetic resonance imaging. We accounted the number of sectors with negative visual responses for both methods. A simple logistic regression analysis was used to evaluate the association between the tumor dimensions and the visual field features RESULTS: Three patients had preserved visual fields, three patients showed hemianopic defects, and eight patients had generalized visual field losses at both evaluations. We observed that the three maximum diameters of the tumor and total tumor volume had different predictive abilities regarding the extent of visual field loss when using psychophysical and mfVECP data. The maximum craniocaudal diameter of the tumor was the better predictor of the psychophysical measurements, whereas for the mfVECP results, all tumor dimensions and volumes had similar values that predict visual field losses.

CONCLUSION

Tumor size as a predictor of visual loss has potential to assist in the clinical intervention and to prevent the irreversible visual impairment caused by tumors of the sellar region.

Measuring degeneration of the lateral geniculate nuclei from pituitary adenoma compression detected by 7T ultra-high field MRI: a method for predicting vision recovery following surgical decompression of the optic chiasm

OBJECTIVE

Predicting vision recovery following surgical decompression of the optic chiasm in pituitary adenoma patients remains a clinical challenge, as there is significant variability in postoperative visual function that remains unreliably explained by current prognostic factors. Available literature inadequately characterizes alterations in adenoma patients involving the lateral geniculate nucleus (LGN). This study examined the association of LGN degeneration with chiasmatic compression as well as with the retinal nerve fiber layer (RNFL), pattern standard deviation (PSD), mean deviation (MD), and postoperative vision recovery. PSD is the degree of difference between the measured visual field pattern and the normal pattern ("hill") of vision, and MD is the average of the difference from the age-adjusted normal value.

METHODS

A prospective study of 27 pituitary adenoma patients and 27 matched healthy controls was conducted. Participants were scanned on a 7T ultra-high field MRI scanner, and 3 independent readers measured the LGN at its maximum cross-sectional area on coronal T1-weighted MPRAGE imaging. Readers were blinded to diagnosis and to each other's measurements. Neuro-ophthalmological data, including RNFL thickness, MD, and PSD, were acquired for 12 patients, and postoperative visual function data were collected on patients who underwent surgical chiasmal decompression. LGN areas were compared using two-tailed t-tests.

RESULTS

The average LGN cross-sectional area of adenoma patients was significantly smaller than that of controls (13.8 vs 19.2 mm2, p < 0.0001). The average LGN cross-sectional area correlated with MD (r = 0.67, p = 0.04), PSD (r = -0.62, p = 0.02), and RNFL thickness (r = 0.75, p = 0.02). The LGN cross-sectional area in adenoma patients with chiasm compression was 26.6% smaller than in patients without compression (p = 0.009). The average tumor volume was 7902.7 mm3. Patients with preoperative vision impairment showed 29.4% smaller LGN cross-sectional areas than patients without deficits (p = 0.003). Patients who experienced improved postoperative vision had LGN cross-sectional areas that were 40.8% larger than those of patients without postoperative improvement (p = 0.007).

CONCLUSIONS

The authors demonstrate novel in vivo evidence of LGN volume loss in pituitary adenoma patients and correlate imaging results with neuro-ophthalmology findings and postoperative vision recovery. Morphometric changes to the LGN may reflect anterograde transsynaptic degeneration. These findings indicate that LGN degeneration may be a marker of optic apparatus injury from chiasm compression, and measurement of LGN volume loss may be useful in predicting vision recovery following adenoma resection.

The Predictive Role of Intraoperative Visual Evoked Potentials in Visual Improvement After Endoscopic Pituitary Tumor Resection in Large and Complex Tumors: Description and Validation of a Method

BACKGROUND

With the advent of extensive endoscopic approaches for pituitary tumors, there has also been an increase in surgery for larger and more complex tumors. Intraoperative manipulation during endoscopic resection of sellar tumors poses potential risk in postoperative visual function in this tumor population. This study proposes a method of accurate intraoperative monitoring of visual evoked potentials (VEPs) and its role in predicting visual function outcomes.

METHODS

Intraoperative VEPs were monitored for 42 resections from a single surgical team, with average tumor size of 2.84 cm. Changes in VEP amplitude and latency in excess of 50% were considered significant. Preoperative and postoperative visual information was obtained from ophthalmology and hospital records, along with patient demographics, comorbidities, and tumor characteristics.

RESULTS

Patients were stratified as experiencing deteriorations in VEPs that did not restore to baseline (n = 4), deteriorations in VEPs that did restore to baseline (n = 6), no change in VEPs (n = 31), and improvement in VEPs (n = 1). Correlation between VEP changes and postoperative visual fields was measured through univariate ordered logistic regression. Improved intraoperative VEP measurements were associated with odds ratio (OR) of visual field improvement of 3.15 (95% confidence interval, 1.15-8.59). Specifically, changes in VEP amplitude were positively associated with visual field improvement with OR of 4.35 (OR, 1.29-14.7). No association was observed between VEPs and other patient or tumor characteristics.

CONCLUSION

Changes in VEP amplitude during endoscopic sellar tumor resection correlate with postoperative visual function. Intraoperative VEP monitoring can serve an important role in preventing postoperative visual field loss.

Visual Outcome of Patients with Pituitary Adenomas Following Surgery and Its Contributory Factors at a Tertiary Hospital in Ghana

Background

Craniotomy and transphenoidal microsurgery are surgical options for treatment of pituitary adenoma at Korle Bu Teaching Hospital(KBTH). Despite major advances and reported success rates of transphenoidal resection globally, paucity of local data regarding visual outcome of either procedure exists. We evaluated the visual outcome of patient with pituitary adenoma following surgery in a tertiary hospital in Ghana.

Methods

This is a prospective study of 18 of 45 consecutive new patients with pituitary adenoma seen from November 2010 to July 2013 at Korle-Bu Teaching Hospital(KBTH), Accra, Ghana. Sixteen (88.9%) of the 18 had surgery by transphenoidal route and 2(11.1%) by craniotomy. All patients had macroadenoma (tumour size >1cm) and histological confirmation of diagnosis. Pre-operative and post-operative visual acuity and its relationship to tumour size and duration of symptoms before diagnosis were evaluated.

Results

Data on 18 patients aged 33–60 years, mean (SD) 45.9±8.5, was analysed. Eleven (61.1%) were females. Visual blur, 15(83.3%), and headache,13(72.2%), were predominant presenting complaints. Common neuro-ophthalmic signs included unilateral or bilateral optic atrophy, 17(94.4%), Relative Afferent Pupillary Defect (RAPD) in 8(44.4%) and impaired colour vision in 32 of 36(88.9%) eyes. Preoperatively, 8(22.2%) and 13(36.1%) of 36 eyes were visually impaired or blind respectively. Postoperatively, 6(16.7%) eyes were visually impaired and 17(47.2%) eyes blind. Blindness was associated with late presentation (p<0.005) and larger tumour width (p<0.036).

Conclusions

More than a third of eyes of patients with pituitary adenoma were blind before and after surgery. Blindness was associated with late presentation and larger tumours. Transphenoidal surgery may be beneficial following early diagnosis to avoid irreversible blindness/visual impairment.

Compressive Lesions of the Optic Chiasm: Subjective Symptoms and Visual Field Diagnostic Criteria

We investigated the diagnostic ability of a new criterion (simple temporal depression) for compressive lesions of the optic chiasm. The subjects were 124 eyes with compressive lesions of the optic chiasm. The controls were 84 eyes. The Humphrey (Carl Zeiss) visual field test was used for visual field testing. The simple temporal depression index was calculated as the ratio of the sums of the thresholds for one line on the nasal side and temporal side of the vertical meridian. The result of new index was 87% sensitivity and 99% specificity. This result suggested that our new criterion will assist the diagnosis in the future.

Factors Affecting Visual Field Outcome Post-Surgery in Sellar Region Tumors: Retrospective Study

Background

Despite the broad category of differentials for sellar region, most of them present with similar clinical signs and symptoms. Headache and visual disturbance are among the frequently seen as presenting symptom. Visual field (VF) assessment is one of the crucial component of neuroophtalmologic assessment and mean deviation (MD) value from automated perimetry allows quantification of the visual field defect. We formulated a study to look into the factors that affect the visual field outcome after surgery.

Methods

All patients with sellar region tumor who has underwent surgery in Queen Elizabeth Hospital from July 2010 to July 2016 were retrospectively analysed through hospital notes. VF assessment via Humphrey visual assessment for these patient pre and post-surgery were reviewed for MD value.

Results

Eighty four patients were recruited and out of them, 151 eyes were taken into analysis after excluding eyes with missing data. Mean age of patients were 45.4 years with 70.2% of them were male. Visual disturbance is the commonest presenting symptom with mean duration of symptom prior to surgery is 9.7 months. Majority of them were pituitary adenomas (75%) followed by sellar meningioma (19%), craniopharyngioma (4.8%), and rathke cleft cyst (1.2%). 70.9% of patients showed improvement in VF based on MD outcome. Mean MD for pre surgery and post-surgery were -14.0 dB and -12.4 dB, respectively. Univariate analysis reveals younger age, female sex, shorter duration of symptom, pituitary adenoma, transsphenoidal approach, and transcranial approach favours improvement in VF. Multivariate analysis shows only shorter symptom duration, transphenoidal approach, and transcranial approach are significant for favourable VF outcome when other factors adjusted.

Conclusion

Symptom duration and surgical approach were independent factors that affects the visual field after surgery in patients with sellar region tumors.

Clinical characteristics and ophthalmologic findings of pituitary adenoma in Korean patients

PURPOSE

To investigate the clinical characteristics of and ophthalmic findings in Korean patients diagnosed with a pituitary adenoma.

METHODS

The medical records of 534 patients diagnosed with a pituitary adenoma at Kyung Hee University Hospital between January 2007 and December 2016 were retrospectively reviewed.

RESULTS

Mean patient age was 47.9 ± 16.2 years. The most common symptoms at the time of presentation were headache (26.2%) and visual disturbance (12.4%). The referral rate to the ophthalmology department was 18.44% and patients most often presented to the neurosurgery department. Optic chiasm compression was identified in 23.4% of patients (54.4% of patients referred to ophthalmology, 15.0% of patients not referred to ophthalmology). Normal visual field (57%) was the most common visual field feature followed by bitemporal hemianopsia (17.8%). Optic chiasmal compression without visual field defects was found in 36.1% of patients. Tumor volume was positively correlated with visual field pattern standard deviation (PSD, p = 0.020) and best-corrected logMAR visual acuity (p = 0.000) and negatively associated with tumor volume and visual field mean deviation (MD, p = 0.000). Best-corrected visual acuity (p = 0.000), MD (p = 0.001), and PSD (p = 0.028) significantly improved after surgery.

CONCLUSIONS

Pituitary adenoma patients do not always have ocular symptoms at their first presentation, even when optic chiasm compression and visual field deficits are present. Therefore, collaboration with an ophthalmologist is important when evaluating pituitary adenoma patients.

The Utility of Magnetic Resonance Imaging in Assessing Patients With Pituitary Tumors Compressing the Anterior Visual Pathway

BACKGROUND

Pituitary tumors are one of the most common types of intracranial neoplasms, and can cause progressive visual loss. An ongoing challenge in the management of patients with pituitary tumors is the cost, availability, and reliability of current magnetic resonance imaging (MRI) techniques to capture clinically significant incremental tumor growth. The purpose of this study was to evaluate the various MRI-based structural analyses and to explore the relationship between measures of structure and function in the afferent visual pathway of patients with pituitary tumors.

METHODS

We performed a critical review of literature on MRI-based structural analyses of pituitary adenomas using PubMed, Embase, Cochrane Library, and Google Scholar. In addition, preoperative structural characteristics of the optic apparatus, optic nerve compression, and optic chiasm elevation identified as important in the literature review, were examined in 18 of our patients from October 2010 to January 2014.

RESULTS

In our review of literature, a total of 443 citations were obtained from our search strategy and review of bibliographies. Eight of these studies met inclusion/exclusion criteria and were retrieved for critical review. Of the 8 included studies, only 2 studies examined the relationship between MRI-based structural measurements and postoperative visual recovery. In our small case-series, MRI analysis of chiasm elevation, severity of optic nerve compression, chiasm position, height of chiasm, tumor height, and tumor volume failed to differentiate patients with postoperative visual dysfunction vs those with visual recovery (P > 0.05).

CONCLUSIONS

Although MRI-based structural analysis is an important and useful tool for managing patients with pituitary tumors, there are limited objective measures shown to be predictive of postoperative visual recovery.

Quantitative Analysis of the Displacement of the Anterior Visual Pathway by Pituitary Lesions and the Associated Visual Field Loss

Purpose

To evaluate quantitatively the relationship between the displacement of anterior visual pathway structures by pituitary tumors and visual field damage with the goal of improving diagnosis and management.

Methods

Subjects had pituitary macroadenomas and both magnetic resonance imaging (MRI) and static perimetry. Neuroradiologists measured the displacement of anterior visual pathway structures and right–left tumor asymmetry. To quantify the degree and laterality of visual field loss, we used algorithms from the neurologic hemifield test to analyze each right–left pair of visual fields with respect to temporal asymmetry, the proportion of loss that was temporal, total asymmetry, and total damage. We compared these metrics with the displacement of anterior visual pathway structures and tumor asymmetry.

Results

Of 114 subjects, 64 (56%) were male and the median age was 57 years (range, 14–88). The summation of vision loss in both eyes and the proportion of temporal loss were statistically significantly related to the maximum displacement of the anterior visual pathway (both P < 0.001 for fit of linear regression). The relationship between the asymmetry of visual field loss in the two eyes and the subjective assignment of tumor asymmetry on MRI did not achieve statistical significance (P = 0.06 by analysis of variance).

Conclusions

Displacement of the anterior visual pathway by pituitary tumors is associated with both the total amount of visual field loss and the proportion of temporal visual field loss. Although there was right–left asymmetry of vision loss in some subjects, it was not related to the subjective assessment of tumor asymmetry.

Factors Affecting the Visual Outcome of Pituitary Adenoma Patients Treated with Endoscopic Transsphenoidal Surgery

OBJECTIVE

To evaluate visual acuity (VA) and visual fields (VF) quantitatively before and after endoscopic transsphenoidal surgery (ETS), with special attention to prognostic factors such as the pituitary adenoma (PA) suprasellar extension (SSE), volume and the patients' age.

METHODS

Medical records of 47 patients with PA undergoing ETS were evaluated. VA, VF, preoperative visual impairment score (VISpre) and postoperative visual impairment score (VISpost) were determined. The PA SSE, volume, chiasmal contact, and their correlation with visual function were assessed preoperatively and postoperatively.

RESULTS

The final cohort included 47 patients. VA improved in 54 of 76 eyes (71.0%) after ETS, and 69 of 76 eyes (90.7%) gained normal VA. Postoperative VF recovery occurred in 32 of 37 eyes (86.5%). The mean change in VIS was 12.0 (95% confidence interval [CI], 7.7-16.3) and improved in all patients with tumor-related visual impairment (n = 25). However, visual outcome was poorer when VISpre was greater than 40. When VISpre was 21-40, age linearly correlated with VIS improvement (P = 0.03); younger patients had satisfactory and older poorer visual outcome. The mean SSE in patients with VF defects (n = 20) was 16.6 mm (95% CI, 13.3-19.9). Mean SSE in patients with no VF defects (n = 23) was 6.6 mm (95% CI, 4.9-8.3; P < 0.001), and the cutoff value for visual perturbations was 9.5 mm for SSE and 8.6 mL for PA volume (P < 0.001 for both).

CONCLUSIONS

The visual outcome after ETS for PAs was excellent, and serious complications were rare. Severe preoperative visual impairment resulted in poorer postoperative visual outcomes. The SSE of the PA was the most important predictor of visual outcome after ETS.

Retina ganglion cell/inner plexiform layer and peripapillary nerve fiber layer thickness in patients with acromegaly

Increased secretion of growth hormone and insulin-like growth factor-1 in acromegaly has various effects on multiple organs. However, the ocular effects of acromegaly have yet to be investigated in detail. The aim of the present study was to compare retina ganglion cell/inner plexiform layer (GCIPL) and peripapillary nerve fiber layer thickness (pRNFL) between patients with acromegaly and healthy control subjects using spectral domain optical coherence tomography (SD-OCT). This cross-sectional, comparative study included 18 patients with acromegaly and 20 control subjects. All participants underwent SD-OCT to measure pRNFL (in the seven peripapillary areas), GCIPL (in the nine ETDRS areas), and central macular thickness (CMT). Visual field (VF) examinations were performed using a Humphrey field analyzer in acromegalic patients. Measurements were compared between patients with acromegaly and control subjects. A total of 33 eyes of 18 patients with acromegaly and 40 eyes of 20 control subjects met the inclusion criteria of the present study. The overall calculated average pRNFL thickness was significantly lower in patients with acromegaly than in control subjects (P = 0.01), with pRNFL thickness significantly lower in the temporal superior and temporal inferior quadrants. Contrary to our expectations, pRNFL thickness in the nasal quadrant was similar between acromegalic and control subjects. The mean overall pRNFL thickness and superonasal, nasal, inferonasal, and inferotemporal quadrant pRNFL thicknesses were found to correlate with the mean deviation (MD) according to Spearman's correlation. However, other quadrants were not correlated with VF sensitivity. No significant difference in CMT values was observed (P = 0.6). GCIPL thickness was significantly lower in all quadrants of the inner and outer macula, except for central and inferior outer quadrants, in the acromegaly group than that in the control group (P < 0.05). GCIPL thicknesses of the inferior inner and outer macula quadrants were found to correlate with MD, whereas no correlation was observed between other quadrants and VF sensitivity. We demonstrated that GCIPL thickness decreased in patients with acromegaly compared with that in control subjects. However, the nasal quadrant pRNFL thickness was similar in acromegaly, in contrast to our expectations. SD-OCT may have utility in the assessment of the effects of acromegaly on retinal structures.

Predictive model for recovery of visual field after surgery of pituitary adenoma

Visual field defect is a major indication for surgery of pituitary adenoma, but visual outcome after surgery is difficult to predict. We developed a nomogram that predicts postoperative restoration of visual field defects in patients with pituitary adenoma. This study was a retrospective cohort investigation of patients who were treated for pituitary adenoma between January 2009 and December 2013. We enrolled 111 eyes of 57 patients who completed one ophthalmological evaluation preoperatively and at least two evaluations within 6 months after surgery. Serial changes in visual fields and retinal nerve fiber layer (RNFL) thickness were evaluated. Multiple logistic regression analysis was performed to select prognostic variables, and a nomogram to predict restoration of visual field defects was constructed. Visual field defects continuously improved until 3 months after surgery. However, average, superior, and inferior RNFL thickness continuously decreased until 6 months after surgery. Multiple logistic regression analysis revealed that worse preoperative visual field defect (p = 0.018), high MRI compression grade (p = 0.009), and inferior RNFL thinning (p = 0.011) were significantly associated with worse visual outcome. The nomogram that predicts the visual restoration showed an area under the receiver operating characteristic curve of 0.84. In conclusion, we developed a nomogram that predicted the restoration of visual field defects after removal of pituitary adenoma. This would allow tailored counseling of individual patients by precisely predicting visual recovery after surgery.

Visual Defects in Patients With Pituitary Adenomas: The Myth of Bitemporal Hemianopsia

OBJECTIVE

The objective of this study was to test the hypothesis that bitemporal hemianopsia (BHA) is the most common visual field (VF) defect in patients with pituitary macroadenoma and to assess the degree of optic pathway compression necessary to produce visual defects.

MATERIALS AND METHODS

We reviewed the MRI findings and medical records of 119 patients with pituitary macroadenoma who had undergone formal assessment of VFs. We then evaluated the degree of optic pathway displacement caused by the pituitary macroadenoma, as observed on MR images. The classifications of optic pathway displacement included no contact, abutment but no displacement, mild displacement (< 3 mm), and moderate displacement (≥ 3 mm). Qualitative analysis classified VFs as normal or as having defects that were monocular, bitemporal, mixed (bitemporal with additional defects), homonymous, or nonspecific.

RESULTS

A total of 89 of 115 patients had an abnormal VF. Only one patient had true BHA. The most common defects were bitemporal or mixed defects (in 49 of 115 patients [42.6%]), likely because more than just the chiasm is often compressed by the pituitary macroadenoma. Classification of optic pathway displacement by the pituitary macroadenoma was as follows: 23 patients had no contact, eight had abutment but no displacement, 27 had mild displacement, and 57 had moderate displacement. In 78 of the 92 patients (84.8%) with pituitary macroadenoma that had contact with the optic pathway, contact was with the optic chiasm and the prechiasmal optic nerve. Of the 49 patients with bitemporal or mixed defects, 42 had moderate displacement of the optic pathway caused by their tumors.

CONCLUSION

BHA is exceedingly uncommon in patients with pituitary macroadenoma. However, although bitemporal and mixed defects are the most common abnormal VF findings, they were found in only 42.6% of patients. Such defects rarely occur if the tumor displaces the optic pathway less than 3 mm from baseline.

Visual findings as primary manifestations in patients with intracranial tumors

AIM

To evaluate the visual findings as primary manifestations in patients with intracranial tumors.

METHODS

The medical charts of the patients with intracranial tumors who initially admitted to the Neuro-ophthalmology and Strabismus Department with ocular complaints between August 1999 and December 2012 were reviewed retrospectively. The detailed clinical history and the findings of neuro-ophthalmologic examination were recorded. Ocular symptoms and signs, the types and locations of intracranial tumors, and the duration of symptoms before the diagnosis were evaluated.

RESULTS

The mean age of 11 women (61.1%) and 7 men (38.9%) was 42.2±11.0 (range 20-66y) at the time of intracranial tumor diagnosis. Initial symptoms were transient visual obscurations, visual loss or visual field defect in 16 cases (88.9%), and diplopia in 2 cases (11.1%). Neuro-ophthalmologic examination revealed normal optic discs in both eyes of 6 patients (33.3%), paleness, atrophy or edema of optic disc in 12 patients (66.7%), and sixth cranial nerve palsy in 2 patients (11.1%). Visual acuity ranged between normal vision and loss of light perception. Cranial imaging demonstrated craniopharyngioma (n=1), plasmacytoma (n=1), meningioma (n=6; olfactory groove and tuberculum sellae, pontocerebellar angle, anterior cranial fossa, frontal vertex, suprasellar region), and pituitary macroadenoma (n=10). The mean duration between the onset of visual disturbances and the diagnosis of intracranial tumor was 9.8±18mo (range 3d-6y).

CONCLUSION

The ophthalmologist is frequently the first physician to encounter a patient with clinical manifestations of intracranial tumors that may cause neurological and ocular complications. Neuro-ophthalmologic findings should be carefully evaluated to avoid a delay in the diagnosis of intracranial tumors.

The influence of pituitary adenoma size on vision and visual outcomes after trans-sphenoidal adenectomy: a report of 78 cases

OBJECTIVE

The aims of this study were to investigate the quantitative relationship between pituitary macroadenoma size and degree of visual impairment, and assess visual improvement after surgical resection of the tumor.

METHODS

The medical records of patients with pituitary adenoma, who had undergone trans-sphenoidal adenectomy between January 2009 and January 2011, were reviewed. Patients underwent an ocular examination and brain MRI before and after surgery. The visual impairment score (VIS) was derived by combining the scores of best-corrected visual acuity and visual field. The relationship between VIS and tumor size/tumor type/position of the optic chiasm was assessed.

RESULTS

Seventy-eight patients were included (41 male, 37 female). Thirty-two (41%) patients experienced blurred vision or visual field defect as an initial symptom. Receiver operating characteristic curve analysis showed that tumors <2.2 cm tended to cause minimal or no visual impairment. Statistical analysis showed that 1) poor preoperative vision is related to tumor size, displacement of the optic chiasm in the sagittal view on MRI and optic atrophy, and 2) poorer visual prognosis is associated with greater preoperative VIS. In multivariate analysis the only factor significantly related to VIS improvement was increasing pituitary adenoma size, which predicted decreased improvement.

CONCLUSION

Results from this study show that pituitary adenomas larger than 2 cm cause defects in vision while adenomas 2 cm or smaller do not cause significant visual impairment. Patients with a large macroadenoma or giant adenoma should undergo surgical resection as soon as possible to prevent permanent visual loss.

Visual acuity and pattern of visual field loss at presentation in pituitary adenoma

Our purpose was to analyse the demographics, prevalence and pattern of visual field defects in patients with pituitary adenoma. We prospectively recruited 103 consecutive patients (206 eyes) presenting to a neurosurgical unit with pituitary adenoma. Ophthalmological examination and standard automated perimetry (Humphrey, 24-2 threshold) was performed. Severity of visual field defects was also assessed. The mean population age was 53.9 years (standard deviation=15). Visual loss was the most common reason for presentation (39%) followed by endocrine abnormality (21%) and headache (15%). Patients with endocrine abnormality on presentation were 10.9 years younger than those presenting with visual loss (p=0.001). Bitemporal defects were the most prevalent pattern (n=22, 41%) followed by homonymous defects (n=7, 13%). Of the patients with visual field loss, 33% had unilateral visual field defects. The mean visual acuity in those with bitemporal defects was 6/7.5 with half of these patients having 6/6 vision in both eyes. In conclusion, the majority of patients with pituitary adenoma have visual acuity better than 6/7.5 despite having visual field defects. While a bitemporal pattern of visual field loss is the most common, a significant proportion of patients had unilateral and altitudinal defects. Assessment of the visual field is essential to rule out chiasmal compression.

Measurement of pancreatic volume by abdominal MRI: a validation study

Objective

To develop abdominal magnetic resonance imaging (MRI) protocol to measure pancreatic volume in humans and to validate it in large animals.

Materials and Methods

We performed abdominal MRI in eight mini-pigs using a clinical 3T MRI system. We used consecutive parallel abdominal slices, covering the entire pancreas to calculate pancreatic volume. Following MRI, animals were sacrificed, the pancreas was removed, and the volume of the pancreas was measured by water displacement. We used the same MRI protocol to measure pancreatic volume in 21 humans. To assess reproducibility of in vivo measurement we repeated MRI pancreas volume evaluation within 24 hours in additional five humans.

Results

In mini-pigs the measurements of pancreatic volume by MRI and by water displacement were almost identical (R² = 0.9867; p<0.0001). In humans the average pancreas volume was 72.7+/−4.5 ml, range from 35.0 to 105.5 ml. This result is in strong agreement with results of previous large postmortem and computed tomography (CT) studies. Repeated measurements of pancreatic volume in humans were highly reproducible. Pancreatic volume measured in vivo was negatively correlated with age, body fat mass, pancreatic TG levels, and visceral fat mass.

Conclusions

These initial results are highly encouraging and our protocol for pancreatic volume estimation in vivo may prove useful in obesity research to follow in vivo changes of pancreatic volume and structure during time course of obesity and type 2 diabetes development.