With the development of various imaging equipments and technologies,the manifestation capability of disease raised, and the application fields extended.Imaging examinations including CT and MRI should play a more marked role in the diagnosis and definition of treatment plans in ophthalmic diseases.(Ophthalmol CHN,2007,16:289-290)

Functional imaging is a newly arisen interdisciplinary subject compared with the routine radiology displaying anatomy and morphology of lesions. It can exhibit the function-changed information, such as blood flow and metabolism of organs and tissues as visual images or data to provide organizational functions and metabolic information, which makes early diagnosis, more accurate orientation, qualitative definition, and also the prognosis judgment. The ophthalmologists should pay more attention to the functional imaging applications in the field of neuro-ophthalmology.

With the rapid development of modem medical imaging technology,imaging examination especially CT and MRI plays an increasingly important role in the quantitative analysis of ophthalmic diseases,including the measurement of orbital volume with CT, the morphological changes of extraocular muscles in different eye positions,changes of oxygen pressure of the retina and the breakdown of blood-retinal barrier,the quantitative analysis of fiber bundles of visual pathway and so on.In this paper,a brief review was made about the application of imaging measurement with CT and MRI in ophthalmic diseases.

The function of the retina is sensitive to oxygen tension, and any changes in oxygen perfusion associated with retinal vessel diseases, such as diabetic retinopathy could affect inner retinal oxygen responses (ΔPO_2). However, the application of currently available techniques in measurements of the retinal oxygenation is limited. Recently, with the development of MRI, it is possible to detect ΔPO_2 noninvasively, and the effects are satisfactory. The application of MR based measurements of ΔPO_2 following the shift from breathing room air were reviewed in this article.

Objective To measure the size and area of the vestibule of normal inner ear to provide basic data for further study of the vestibule-related diseases.Methods Two hundred forty patients (480 ears) who underwent temporal bone 64 slices CT scans were enrolled in this study from April 2011 to July 2012.These patients were divided into 4 groups,including Child group (＜ 18 years),Youth group (18-44 years),Adult group (45-59 years),and Elder group (≥ 60 years).The size and area of the vestibules were measured on the multiplanar reformatted images in post-processing workstation.Results There were no statistically significant differences in the size and area of vestibules in sides,genders and among the different groups (P ＞ 0.05),while there were statistically significant differences of those in different positions (P ＜ 0.05).Conclusion The measurements in different planes were as follow:1) In axial plane,the length of vestibule and its 95％ confidence interval were (5.89 ± 0.34),5.22-6.56 mm,respectively; the width (2.47 ± 0.36),1.76-3.18 mm; the area(13.97 ± 1.71) 10.62-17.32 mm2 2) in coronal plane,the length of vestibule and its 95％ confidence interval were (5.10 ± 0.32),4.47-5.73 mm,respectively; the width (2.42 ± 0.21),2.01-2.83 mm; the area (11.30 ± 1.33),8.69-13.91 mm2 ;3)in sagittal plane,the length of vestibule and its 95 ％ confidence interval were(5.27 ± 0.33),(4..62-5.92) mm,respectively; the width (3.72 ± O.35),(3.03--4.41) mm; the area (13.77 ± 1.55),(10.73-16.81)mm2.The volume CT combined with post-processing technology can accurately measure the size and area of the vestibules.The data can provide quantitative basis for diagnosis of the vestibule-related diseases.

Objective To investigate 16-slice spiral CT findings of bony canals of the internal auditory canal ( IAC ) fundus withmultiplanar reformation (MPR) and provide evidence for dignosis of lesions in the IAC fundus and surgery.Methods CT scan of thetemporal bone was performed in 30 volunteers. Bony canals of the IAC fundus were measured in images acquired with MPR.Results The mean?SD measurements (in mm) of the anteroposterior diameter and superoinferior diameter of fundus of the IAC was (4.07?0.97) mm and (3.24?0.88) mm respectively. The mean?SD measurements (in mm) of the length and width of bony canal for the labyrinthinesegment of the facial nerve was (3.04?0.52) mm and (0.96?0.31) mm, respectively. The mean?SD measurements (in mm) of the length and width of bony canal of the superior vestibular nerve was (2.52?0.48) mm and (0.83?0.30) mm respectively. The mean?SD measurements (in mm) of the length and width of bony canal of the cochlear nerve was (0.89?0.19) mm and (2.05?0.39) mm respectively. The mean?SD measurements ( in mm ) of the length and width of bony canal of the inferior vertibular nerve was ( 1.07?0.23 ) mm and (0.73?0.21) mm respectively. The mean?SD measurements ( in mm ) of the length and width of singular canal was (3.56?0.68) mm and (0.56?0.11) mm respectively . Conclusion MPR with 16-slice spiral CT can demonstrate the shape and measurements of the IAC fundus,which would contribute in dignosis of lesions in the IAC fundus and surgery.

Objective To describe CT and MRI imaging findings of retinal hamartomas with tuberous sclerosis and evaluate their clinical value.Design Retrospective case series.Participants 7 patients of tuberous sclerosis complex(TSC) who have ocular lesions found with CT and MRI examination.Methods 7 patients with tuberous sclerosis were diagnosed by clinical data and head CT.The size,morphology,density and enhancing situation of the retinal lesions were observed with CT and MRI,as while as with direct or indirect fundoscopy.Main Outcome Measures CT and MRI features of ocular lesions.Results 7 cases displayed intracranial calcification and/or non-calcified tubercles,situating in subendyma(7 cases,accounting for 100%) by head CT.Orbital CT and MRI showed 4 cases (57.1%) of flat retinal hamartomas 3 cases(42.9%) of retinal lobular and nodular hamartomas,2 cases(28.6%) scattered calcification patches in hamartoma,and 2 cases(28.6%) of nanophthalmos.The lesions displayed unenhancement on contrast-enhanced MR images in 7 cases(100%).There was 1 case(14.3%) of progressive retinal astrocytic hamartoma.Conclusion The examination of CT and MRI may find the bigger retinal hamartomas,which can play a very important role at the diagnosis with the help of whole brain examination. For progressive retinal astrocytic hamartoma,systemic evaluation with CT and MRI can provide evidence for choosing appropriate thera- pies.

Objective To investigate the value of CT and MRI in diagnosing nasopharyngeal angiofibromas.Methods 18 cases of nasopharyngeal angiofibromas were retrospectively analyzed including the location, density ,signal intensity, extension of tumors and changes of surrounding bones.Results 16 cases located in the area around sphenopalatine foramen. 6 cases exhibited homogeneous density on CT scans(6/11 cases) and 12 cases displayed inhomogeneous signal intensity on MR scans(12/14 cases). All the Fourteen MRI examinations revealed vice signal by vessels, inhomogeneous enhancement and extensive invasion along the foramina or fissures.Conclusion MRI not only determines the location and traces out the extension of nasopharyngeal angiofibroma more exactly, but also displayes its diagnostic signal fashion. Namely MRI has greater value in diagnosing this tumor than CT.

Objective To observe the morphological features of the incisive canal in normal anatomy and abnormalities with multi-slice spiral CT (MSCT). Methods MSCT findings of 108 normal subjects and 65 patients with abnormalities involving incisive canal were retrospectively analyzed. Results The normal incisive canal were classified into 3 types according to the morphology of the nasal opening:two openings, short bony crest and one opening (37.04%, 33.33% and 29.63%, respectively), as well as cylinder, Y-shaped and pyramidal (59.26%, 37.04% and 3.70%) in coronal images, and cylinder, pyramidal and fusiform (84.26%, 14.81% and 0.93%) in sagittal images. The maximum diameter of the nasal and palatal opening was (4.67±1.31) mm and (3.51±0.88) mm (P<0.05). The length of the incisive canal was (10.71±1.95) mm, (11.51±1.97) mm in male and (9.91±1.58) mm in female respectively, and gender difference was found (P<0.05). The angle between the posterior wall and the hard palate was (118.51±9.44)°. The upper and lower length from the anterior wall of the incisive canal to the cortical palate was (9.29±1.26) mm and (7.12±1.21) mm, respectively (P<0.05). The manifestations of abnormalities involving incisive canal including enlargement (47.69%), narrowing (46.15%), shortening (3.08%) and interruption (3.08%) were observed. Conclusion The morphology of the incisive canal can be clearly delineated with MSCT and post processing techniques. It is extremely valuable for avoiding potential complications during surgical procedures such as implant placement and helpful to the diagnosis and treatment of abnormalities involving maxillary incisive canal.

Objective To investigate diagnostic value of CTA for traumatic pseudoaneurysms (TPA) in the cavernous segment of the internal carotid artery (ICA) when they rupture into the sphenoid sinus. Methods CTA of 7 patients with TPA in the cavernous segments of ICA verified by DSA were retrospectively analyzed. All the patients were performed CTA scanning. The post-processing techniques included VR,MIP,MPR, and CPR. Results All the CTA images of 7 patients showed irregular mass in the sphenoid sinus with obviously enhancement in the same phase to ICA, which communicating with ICA in wide base. The peripheral area of the mass showed no enhancement. The size varied from 3 mm × 2 mm × 1 mm to 33 mm × 30 mm × 27 mm. The adjacent lateral wall of sphenoid sinus showed fractures in all cases. TPA located at anterior-knee segments of cavernous ICA in 6 cases, and cavernous free segment in 1 case. All the disruptions were found at medial or anterior medial wall of ICA. Conclusions Cranial CTA is the effective non-invasive method for diagnosing TPA in the cavernous segment of ICA when they rupture into sphenoid sinus. Combined using of VR, MIP, MPR, and CPR can delineate the location and size of the sphenoid wall fracture and the ICA rupture, which help to clarify the anatomical relationship between them.