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The current clinical practice consists of visually inspecting and evaluating cine-angiograms of the interested region, which is largely operator-dependent. We present here an automatic method for segmenting the vessel tree and compute a quantitative measure, in terms of fractal dimension (FD), of the vascular complexity. The proposed workflow consists of <jats:italic>three<\/jats:italic> main steps: (<jats:italic>i<\/jats:italic>) conversion of the cine-angiographies to single static images with a broader field of view, (<jats:italic>ii<\/jats:italic>) automatic segmentation of the vascular trees, and (<jats:italic>iii<\/jats:italic>) calculation and assessment of FD as complexity index. In particular, this work defines (1) a method to reduce the inter-observer variability in judging vascular complexity in cine-angiography images from patients affected by peripheral artery occlusive disease (PAOD), and (2) the use of Fractal Dimension as a metric of shape complexity of vascular tree. The inter-class correlation coefficient (<jats:italic>ICC<\/jats:italic>) is computed as inter-observer agreement metric and to account for possible systematic error, that depends on the experience of the raters. The automatic segmentation of vascular tree achieved an Area Under the Curve mean value of <jats:inline-formula><jats:alternatives><jats:tex-math>$$0.77~\\pm ~0.07$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                  <mml:mrow>\n                    <mml:mn>0.77<\/mml:mn>\n                    <mml:mspace\/>\n                    <mml:mo>\u00b1<\/mml:mo>\n                    <mml:mspace\/>\n                    <mml:mn>0.07<\/mml:mn>\n                  <\/mml:mrow>\n                <\/mml:math><\/jats:alternatives><\/jats:inline-formula>, with a min-max range of <jats:inline-formula><jats:alternatives><jats:tex-math>$$0.57-0.87$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                  <mml:mrow>\n                    <mml:mn>0.57<\/mml:mn>\n                    <mml:mo>-<\/mml:mo>\n                    <mml:mn>0.87<\/mml:mn>\n                  <\/mml:mrow>\n                <\/mml:math><\/jats:alternatives><\/jats:inline-formula>. Absolute operator agreement was higher over the segmented image (<jats:inline-formula><jats:alternatives><jats:tex-math>$$ICC=0.96$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                  <mml:mrow>\n                    <mml:mi>I<\/mml:mi>\n                    <mml:mi>C<\/mml:mi>\n                    <mml:mi>C<\/mml:mi>\n                    <mml:mo>=<\/mml:mo>\n                    <mml:mn>0.96<\/mml:mn>\n                  <\/mml:mrow>\n                <\/mml:math><\/jats:alternatives><\/jats:inline-formula>) compared to the video (<jats:inline-formula><jats:alternatives><jats:tex-math>$$ICC=0.76$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                  <mml:mrow>\n                    <mml:mi>I<\/mml:mi>\n                    <mml:mi>C<\/mml:mi>\n                    <mml:mi>C<\/mml:mi>\n                    <mml:mo>=<\/mml:mo>\n                    <mml:mn>0.76<\/mml:mn>\n                  <\/mml:mrow>\n                <\/mml:math><\/jats:alternatives><\/jats:inline-formula>) and the a broader field of view image (<jats:inline-formula><jats:alternatives><jats:tex-math>$$ICC=0.92$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                  <mml:mrow>\n                    <mml:mi>I<\/mml:mi>\n                    <mml:mi>C<\/mml:mi>\n                    <mml:mi>C<\/mml:mi>\n                    <mml:mo>=<\/mml:mo>\n                    <mml:mn>0.92<\/mml:mn>\n                  <\/mml:mrow>\n                <\/mml:math><\/jats:alternatives><\/jats:inline-formula>). Fractal Dimension computed on both manual segmented images (ground truths) and automatically showed a good correlation with the clinical score (0.85 and 0.75, respectively). Experimental analyses suggest that extracting the vascular tree from cine-angiography can substantially improve the reliability of visual assessment of vascular complexity in PAOD. Results also reveal the effectiveness of FD in evaluating complex vascular tree structures.<\/jats:p>","DOI":"10.1007\/s00521-022-07642-2","type":"journal-article","created":{"date-parts":[[2022,8,10]],"date-time":"2022-08-10T17:02:38Z","timestamp":1660150958000},"page":"22015-22022","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Assessing vascular complexity of PAOD patients by deep learning-based segmentation and fractal dimension"],"prefix":"10.1007","volume":"34","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0832-0151","authenticated-orcid":false,"given":"Pierangela","family":"Bruno","sequence":"first","affiliation":[]},{"given":"Maria Francesca","family":"Spadea","sequence":"additional","affiliation":[]},{"given":"Salvatore","family":"Scaramuzzino","sequence":"additional","affiliation":[]},{"given":"Salvatore","family":"De Rosa","sequence":"additional","affiliation":[]},{"given":"Ciro","family":"Indolfi","sequence":"additional","affiliation":[]},{"given":"Giuseppe","family":"Gargiulo","sequence":"additional","affiliation":[]},{"given":"Giuseppe","family":"Giugliano","sequence":"additional","affiliation":[]},{"given":"Giovanni","family":"Esposito","sequence":"additional","affiliation":[]},{"given":"Francesco","family":"Calimeri","sequence":"additional","affiliation":[]},{"given":"Paolo","family":"Zaffino","sequence":"additional","affiliation":[]}],"member":"297","published-online":{"date-parts":[[2022,8,10]]},"reference":[{"issue":"8","key":"7642_CR1","doi-asserted-by":"publisher","first-page":"153","DOI":"10.1161\/CIR.0000000000001052","volume":"145","author":"CW Tsao","year":"2022","unstructured":"Tsao CW, Aday AW, Almarzooq ZI, Alonso A, Beaton AZ, Bittencourt MS, Boehme AK, Buxton AE, Carson AP, Commodore-Mensah Y et al (2022) Heart disease and stroke statistics-2022 update: a report from the american heart association. 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