INTRODUCTION The size, location and depth of the region of interest (ROI) can influence the perfusion variables determined by use of contrast-enhanced ultrasonography (CEUS). The aims of this study is to evaluate this in the kidney and the spleen of conscious dogs. METHODS It is a retrospective study. The dogs included in the study had no kidneys disease for the evaluation of the renal perfusion and no splenic lesions for the evaluation of the splenic perfusion. 25 client-owned adult (1.5 to 2 years old) Labrador Retrievers (15 males and 10 females; mean ± SD body weight, 25.7 ± 5.6 kg), for the evaluation of the kidney, and 15 client-owned adult (5.5 years old mean), of several breeds (2 Bracco Italiano, 8 Cross- breed, 3 Dachshunds, 1 Hound, 1 Pitbull, 8 males and 7 females; mean ± SD body weight, 18.62 ± 5.736 kg), met the inclusion criteria. Each dog received two bolus injections of sulphur hexafluoride (SONOVUE ®, 8μl/mL, Bracco, Milano, Italia) (at dose 0,04ml/kg) during CEUS. For the renal analysis, three small oval ROIs (area of each ROI, 0.11cm2) located in a row with a distance of one mm between adjacent ROIs, and one large oval ROI (area, 1cm2) that encompassed the three smaller ROIs were manually drawn in the renal cortex. The ROIs were located at a depth of 1.5 to 2.0cm from the skin in the near field of the renal cortex. One additional ROI (0.11cm2) was located in the medulla. For the splenic analysis, three square ROIs (area of each 0.05cm2) were located in a row and spaced 1mm apart, with adjacent ROIs at three different depths (9 ROIs in total). Three medium rectangular ROIs (area, 0.3cm2) to encompass the 3 smaller ROIs of each row, 5 and a single, larger, square ROI (area, 1cm2) that encompassed all the previous ROIs were manually drawn in the splenic parenchyma. Software analysis (QONTRAST, AMID-Bracco, Milano, Italia) of time-intensity curves within each ROI in both organs was used to identify peak enhancement, time to peak enhancement, regional blood flow, and mean transit time. RESULTS The location and size of the ROIs did not cause significant differences in the mean values of the renal perfusion variables. In the spleen, the deeper ROIs showed significantly lower values than the superficial ROIs. No differences were found concerning the size. CONCLUSIONS Results of this study indicate that the size of ROI during CEUS evaluation does not cause a significant difference in the assessment of renal or splenic perfusion. In the spleen, ROIs placed superficially and medially generated significantly higher values than deeper ROI measurements; therefore, placement of ROI superficially and medially is advised for assessment of splenic perfusion.
|Titolo:||Effetti delle dimensioni e della localizzazione delle ROI (REGION OF INTEREST) durante lo studio CEUS (CONTRAST ENHANCED ULTRASONOGRAPHY) nella valutazione dei parametri di perfusione vascolare renale e splenica nel cane|
|Data di pubblicazione:||11-nov-2019|
|Appare nelle tipologie:||Tesi di dottorato|