The Change of Retinal Nerve Fiber Layer Thickness after Posterior Chamber Phakic Intraocular Lens Implantation

PURPOSE: In the present study we evaluated the changes of measured retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) after phakic intraocular lens (implantable collamer lens, ICL) implantation and analyzed the factors correlated with the changes of measured RNFL thickness. METHODS: Forty eyes of 40 patients (Group A: 20 patients using spectral domain OCT and Group B: 20 patients using time domain OCT) who underwent ICL implantation were included in this study. RNFL thickness was measured 1 week before surgery and 1 month postoperatively using OCT. The changes of measured RNFL thickness and the correlation between patients' data were analyzed. RESULTS: The postoperative measured RNFL thickness of the average, inferior, temporal, and superior quadrants were increased compared to preoperative measured RNFL thickness in Group A. Group B had similar results in the average, inferior, and superior quadrants (p 0.05). CONCLUSIONS: The measured RNFL thickness after ICL implantation may increase compared to the preoperative value. Caution should be taken when interpreting the RNFL thickness values measured by OCT in patients with myopia who undergo ICL implantation.

The Change of Retinal Nerve Fiber Layer Thickness after Posterior Chamber Phakic Intraocular Lens Implantation

PURPOSE: In the present study we evaluated the changes of measured retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) after phakic intraocular lens (implantable collamer lens, ICL) implantation and analyzed the factors correlated with the changes of measured RNFL thickness. METHODS: Forty eyes of 40 patients (Group A: 20 patients using spectral domain OCT and Group B: 20 patients using time domain OCT) who underwent ICL implantation were included in this study. RNFL thickness was measured 1 week before surgery and 1 month postoperatively using OCT. The changes of measured RNFL thickness and the correlation between patients' data were analyzed. RESULTS: The postoperative measured RNFL thickness of the average, inferior, temporal, and superior quadrants were increased compared to preoperative measured RNFL thickness in Group A. Group B had similar results in the average, inferior, and superior quadrants (p 0.05). CONCLUSIONS: The measured RNFL thickness after ICL implantation may increase compared to the preoperative value. Caution should be taken when interpreting the RNFL thickness values measured by OCT in patients with myopia who undergo ICL implantation.

Usefulness of Rotational Angiography in the Assessment of Cerebral Aneurysm and Arteriovenous Malformation

PURPOSE: To evaluate the role of rotational angiography in the diagnosis, characterization, and postoperativeassessment of aneurysm, and in the analysis of arteriovenous malformation(AVM). MATERIALS AND METHODS: Between May1995 and February 1997, 31 patients who had undergone DSA and rotational angiography were retrospectivelyevaluated. Rotational angiographic and lateral DSA images were compared by two radiologists, and in 22 patientswith aneurysmal clipping, location, visibility of the aneurysmal neck, vascular branch anatomy, and projection andshape of the aneurysm were evaluated. The presence or absence of residual aneurysmal neck was evaluated in eightpostoperative patients, and the anatomy of feeder artery and intranidal aneurysm were evaluated in five AVMpatients. RESULT: Twenty-seven aneurysms were found in 22 of 26 patients in whom DSA had indicated thispossibility. Rotational angiography was superior to conventional DSA in the assessment of neck(67%), vascularbranch anatomy(41%), and projection(22%), location(19%), and shape(15%) of the aneurysm. Rotational angiographyhelped confirm the absence of aneurysm at 11 sites, and was also superior to conventional DSA for confirming theabscence of residual neck in four of eight postoperative patients, and to evaluate feeder artery in four of fiveAVM patients. CONCLUSION: Rotational angiography is better than conventional DSA for the evaluation of aneurysmand AVM.

Contrast-Enhanced Turbo Spin-Echo(TSE) T1-weighted Imaging: Improved Contrast of Enhancing Lesions

PURPOSE: The purpose of this study was to evaluate the effect of contrast improvement of enhancing brain lesions by inherent magnetization transfer effect in turbo spin-echo (TSE) T1-weighted MR imaging. MATERIALS AND METHODS: Twenty-six enhancing lesions of 19 patients were included in this study. Using a 1.0T superconductive MR unit, contrast-enhanced SE T1-weighted images (TR=600 msec, TE=12 msec, NEX=2, acquisition time=4 min 27sec) and contrast-enhanced TSE T1-weighted images (TR=600 msec, TE=12 msec, NEX=2, acquisition time=1min 44sec) were obtained. Signal intensities at enhancing lesions and adjacent white matter were measured in the same regions of both images. Signal-to-noise ratio (SNR) of enhancing lesions and adjacent white matter, and contrast-to-noise ratio (CNR) and lesion-to-background contrast (LBC) of enhancing lesions were calculated and statistically analysed using the paired t-test. RESULTS: On contrast-enhanced TSE T1-weighted images, SNR of enhancing lesions and adjacent white matter decreased by 18%(p<0.01) and 32% (p<0.01), respectively, compared to contrast-enhanced SET1-weighted images. CNR and LBC of enhancing lesions increased by 16% (p<0.05) and 66% (p<0.01), respectively. CONCLUSION: Due to the proposed inherent magnetization transfer effects in TSE imaging, contrast-enhanced T1-weighted TSE images demonstrated a statistically significant improvement in CNR and LBC, compared to conventional contrast-enhanced T1-weighted SE images, and scan time was much shorter.