Introduction Obstruction of the lacrimal drainage represents a common ophthalmologic issue. The blockage may interest any level of the lacrimal drainage pathway, and it is important to find the site of obstruction to plan the most appropriate treatment. In this study, findings from magnetic resonance (MR) dacryocystography were compared with findings from endoscopic and surgical procedures to evaluate the accuracy of MR dacryocystography in localizing the site of nasolacrimal duct obstruction. Methods We enrolled twenty-one patients with clinical suspicion of nasolacrimal duct obstruction who underwent dacryoendoscopy and surgery. MR dacryocystography was performed with a heavily T2-weighted fast spin echo sequence in the coronal planes. Before the MRI was performed, a sterile 0.9% NaCl solution was administered into both conjunctival sacs. For each examination, two independent readers (with 8 and 10 years of experience in head and neck imaging) evaluated both heavily 3D space T2-weighted and STIR sequences. Results Stenosis/obstruction of nasolacrimal duct or lacrimal sac was diagnosed in all 21 patients who underwent MRI dacryocystography. In particular, the site of the obstruction was classified as lacrimal sac in 12 (57%) patients, nasolacrimal duct in 6 (29%) patients, and canaliculi in 3 (14%) patients by both readers. By comparison with the evidence resulting from the endoscopy, there were differences between MRI dacryocystography and dacryoendoscopy in the evaluation of the obstruction’s site in three patients, with an overall accuracy of 85.7%. Conclusion MR dacryocystography allows a non-invasive evaluation of the lacrimal drainage pathway, valid for the planning of the most appropriate treatment.

Seasonal fluctuations of sedimentary Total OrganicCarbon (TOC) and Total ~eldahl Nitrogen (TKN) were investigated in two earthen ponds of a brackishwater extensive fish farm. One was subjected to periodic sediment "ploughing" (hydrocultivation), a practice performed by fishfarmers to oxidise sediments and fertilise the water column. Nutrients and chlorophyll-a were monitored for controlling the impact of hydrocultivation on water overlying treated sedimen ts.The considered variables revealed a dystrophic event occurring in summer, when a dense biomass of macro algae (7-10 kg m· 2 ) died because of a rise in temperature (30'C and over). From July to August a large amount of labile organic matter settled to sediments increasing TOC and TKN from 600 gC ffi"2 and 38.5 gN m· 2 to 1500-1800 gC m· 2 and 50-68 gN m· 2 , respectively. A phytoplankton bloom occurred, increasing living organic matter in the water column, as pointed out by high values of total-N, total-P and chlorophyll-a. Low levels of dissolved oxygen recorded in August attest to the danger represented by high macroalgae biomasses for the considered ecosystem, mainly because of the high oxygen demand induced by rapid decomposition of macroalgae tissues.In mid-October TOC dropped to 870-890 gC m· 2 , and TKN to 42-43 gN m-2 . In the two ponds no important difference in variable trends has been pointed out, despite the periodic "ploughing" interventions, probably because hydrocultivation cannot affect dystrophic environments with such a heavy organic matter recycle.