Relationship between diabetic macular edema and choroidal layer thickness.

PURPOSE: To investigate the relationship between diabetic macular edema (DME) and the choroidal layer thickness in diabetic patients. METHODS: This is a retrospective observation study. Three hundred eighteen eyes of 159 diabetes mellitus (DM) patients and age-matched 100 eyes of 79 healthy controls were enrolled. DME was defined as over 300 µm in the central retinal subfield of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid sector. The central choroidal thickness (CCT), as well as inner and outer layers were determined based on enhanced depth imaging (EDI)-OCT. Diabetic patients with/without systemic diabetic treatments (DT) at the start of this study was defined as DT+ and DT-, respectively. The number of eyes examined was 62 and 256 eyes in DME+and DME-groups, respectively. DM patients were further subdivided into 4 groups with/without DME and DT; DME+DT+(35 eyes), DME-DT+(159 eyes), DME+DT-(27 eyes), and DME-DT-group (97 eyes). Multiple comparisons on CCT layers including control and each DM group were statistically examined. RESULTS: The total CCT layer was 254±83, 283±88, and 251±70 µm in the control, DME+, and DME-group, respectively. A total CCT layer in DME+was significantly thicker than the DME-group (P < 0.05). The outer CCT layer was 195±75, 222±83, and 193±63 µm in the control, DME+, and DME-group, respectively. The outer CCT layer in DME+ was significantly thicker than the DME-group (P < 0.05). In the subdivided groups, the total CCT layers in the control, DME+DT+, DME-DT+, DME+DT-and DME-DT-groups were 254±83, 274±88, 247±66, 290±84 and 258±75 µm, respectively. The outer CCT layers in each group were 195±75, 214±83, 189±58, 228±77, and 201±70 µm, respectively. Total CCT and the outer layer in DME+DT-was significantly thicker than the DME-DT+group (each P < 0.05). In contrast, there was no significant difference in inner layer between the groups. CONCLUSIONS: The total and outer CCT layers of diabetic eyes were significantly thickened in the DME+DT-as compared with the DME-DT+group, suggesting that CCT may be related to the pathology of DME.

Inverse-direction scanning improves the image quality of whole carotid CT angiography with 64-MDCT.

PURPOSE: The purpose of this prospective study was to clarify whether reducing the incidence of perivenous artifacts through craniocaudal scanning improves the quality of 64-multidetecter computed tomography (MDCT) angiography images of the whole carotid artery. METHODS: Forty patients underwent MDCT angiography in the caudocranial (n=20) or craniocaudal (n=20) direction in 2007. All patients were injected with 75 ml of contrast media followed by a 35-ml saline chaser bolus at 4.0 ml/s in the right antecubital vein. Maximum intensity projection (MIP) images were scored according to image quality on a scale of 1-5. Bilateral arterial and venous attenuation was measured on 10 separated slices. We compared the mean image quality score of the two groups (i.e. those scanned caudocranially and those scanned craniocaudally). We analyzed the correlation between vascular attenuation and mean image quality. RESULTS: Compared with the caudocranial group, the craniocaudal group had higher image quality scores (median, 3.70 vs. 3.40; 95% CI, 3.50-3.96 vs. 3.06-3.60; p<0.05), higher arterial attenuation (median, 550 HU vs. 489 HU; range, 270-686 vs. 302-574; p<0.05), and lower maximum venous attenuation (median, 436 vs. 1452 HU; range, 250-617 vs. 377-2044; p<0.01). Multiple regression analysis revealed that the most significant correlation factor with image quality was minimum arterial attenuation (R2=0.42, p<0.001) measured near the brachiocephalic artery. In the caudocranial group only, there was a negative correlation between right brachiocephalic venous attenuation and minimum arterial attenuation. CONCLUSIONS: Compared with conventional caudocranial scanning, craniocaudal scanning improves the image quality of 64-MDCT angiography images of the whole carotid artery.