Browsing by Author "Pitura, Reinis"

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    Comparison between diffusion-weighted sequences with selective and non-selective fat suppression in the evaluation of Crohn's disease activity : are they equally useful?
    (2020-05-27) Apine, Ilze; Pitura, Reinis; Franckevica, Ivanda; Pokrotnieks, Juris; Krūmiņa, Gaida; Department of Radiology; Department of Pathology; Department of Internal Diseases
    Background: We compared the efficiency of two MRI diffusion weighted imaging (DWI) techniques: DWI with SPIR (DWI SPIR) and DWI with STIR (DWI STIR), to estimate their eligibility for quantitative assessment of Crohn's disease activity in children and adults. Methods: In inflamed terminal ileum segments ( n = 32 in adults, n = 46 in children), Magnetic Resonance Index of Activity (MaRIA) was calculated, ADC values of both DWI techniques were measured, and the corresponding Clermont scores calculated. ADC values of both DWI techniques were compared between both and within each patient group, assessing their mutual correlation. Correlations between MaRIA and the corresponding ADC values, and Clermont scores based on both DWI techniques were estimated. Results: No correlation between ADC of DWI SPIR and DWI STIR was observed (rho = 0.27, p = 0.13 in adults, rho = 0.20, p = 0.17 in children). The correlation between MaRIA and Clermont scores was strong in both techniques-in SPIR, rho = 0.93; p < 0.0005 in adults, rho = 0.98, p < 0.0005 in children, and, in STIR, rho = 0.89; p < 0.0005 in adults, rho = 0.95, p < 0.0005 in children. The correlation between ADC and MaRIA was moderate negative for DWI STIR (rho = 0.93, p < 0.0005 in adults, rho = 0.95, p < 0.0005 in children), but, in DWI STIR, no correlation between ADC and MaRIA score was observed in adults (rho = -0.001, p = 0.99), whereas children presented low negative correlation (rho = -0.374, p = 0.01). Conclusions: DWI STIR is not suitable for quantitative assessment of Crohn's disease activity both in children and adult patients.
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    The Influence of Bowel Preparation on ADC Measurements: Comparison between Conventional DWI and DWIBS Sequences
    (2019-07) Apine, Ilze; Baduna, Monta; Pitura, Reinis; Pokrotnieks, Juris; Krumina, Gaida; Department of Radiology; Rīga Stradiņš University; Department of Internal Diseases
    Background and objectives: The aim of the study was to assess whether there were di ff erences between apparent di ff usion coe ffi cient (ADC) values of di ff usion-weighted imaging (DWI) and di ff usion-weighted imaging with background body signal suppression (DWIBS) sequences in non-prepared and prepared bowels before and after preparation with an enteric hyperosmolar agent, to assess whether ADC measurements have the potential to avoid bowel preparation and whether ADC-DWIBS has advantages over ADC-DWI. Materials and Methods: 106 adult patients without evidence of inflammatory bowel disease (IBD) underwent magnetic resonance (MR) enterography before and after bowel preparation. ADC-DWI and ADC-DWIBS values were measured in the intestinal and colonic walls demonstrating high signal intensity (SI) at DWI tracking images of b = 800 s /mm2 before and after preparation. Results: There were significant di ff erence (p < 0.0001) in both ADC-DWI and ADC-DWIBS results between non-prepared and prepared jejunum for DWI being 1.09 x 10 3 mm2 /s and 1.76 x 10 3 mm2 /s, respectively, and for DWIBS being 0.91 x 10 3 mm2 /s and 1.75 x 10 3 mm2 /s, respectively. Both ADC-DWI and DWIBS also showed significant di ff erence between non-prepared and prepared colon (p < 0.0001), with DWI values 1.41 x 10 3 mm2 /s and 2.13 x 10 3 mm2 /s, and DWIBS-1.01 x 10 3mm2 /s and 2.04 x 10 3mm2 /s, respectively. Nosignificant di ff erence between ADC-DWI and ADC-DWIBS was found in prepared jejunum (p = 0.84) and prepared colon (p = 0.58), whereas a significant di ff erence was found in non-prepared jejunum and non-prepared colon (p = 0.0001 in both samples). Conclusions: ADC between DWI and DWIBS does not di ff er in prepared bowel walls but demonstrates a di ff erence in non-prepared bowel. ADC in non-prepared bowel is lower than in prepared bowel and possible overlap with the ADC range of IBD is possible in non-prepared bowel. ADC-DWIBS has no advantage over ADC-DWI in regard to IBD assessment.
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    Repeatability of magnetic resonance measurements used for estimating Crohn's disease activity
    (2020-04-01) Apine, Ilze; Pirksta, Ieva; Pitura, Reinis; Pokrotnieks, Juris; Puķīte, Ieva; Krūmiņa, Gaida; Department of Radiology; Department of Internal Diseases
    The MR activity indices used for quantification and follow-up of Crohn's disease are composed of a number of subjectively determinable components with equivocal repeatability. The purpose of this article was to assess the repeatability of measurements used for quantitative estimation of Crohn's disease activity in the terminal ileum. In five adults (23-57 y.o.) and 12 children (10-17 y.o.) with active terminal ileitis, the inflamed bowel was divided into 3 cm segments (n = 32 in adults, n = 46 in children), and measurements for the calculation of MaRIA and Clermont scores were performed. Parameters included apparent diffusion coefficients (ADC) for diffusion-weighted imaging (DWI) sequences with selective and non-selective fat suppression, wall signal enhancement before (WSI-preGd) and after (WSI-preGd) gadolinium enhancement, bowel thickness, and presence of ulcers. The measurements were standardised (accurate site-to-site comparison, exact ROI size, where applicable) and repeated by the same researcher after two months. Intra-observer agreement for ADC, WSI-preGd and WSI-postGd, bowel thickness was assessed with a paired t-test, and the significant difference in presence/absence of ulcers was assessed by the Pearson 2 test. Absolute difference was not found between the 1st and 2nd measurements of ADC, WSI-preGd, WSI-postGd and wall thickness. There was systematic difference in the presence of bowel ulcers. In standardised conditions the repeatability of ADC, WSI-preGd and WSI-postGd is high. Efforts must be made to precisely define the size and appearance of ulcers that may be included in the index calculation.