Abstract
Aim To assess the feasibility of dynamic contrast-enhanced perfusion-MRI in characterization of active small-bowel inflammation and chronic mural fibrosis in patients with Crohnʼs disease (CD). Methods We analyzed a total of 37 (11 women; 23–69 years) patients with known biopsy proven CD, who underwent MR-enterography (MRE) study, performed on a 1.5 T MRI system (Achieva, Philips), using a phased array sense body multicoil, after oral administration of 1.5–2 L of PEG solution. MRE protocol included T1 weighted, SSh T2, sBTFE, and gadolinium-enhanced THRIVE sequences acquired on coronal and axial planes. A dedicated workstation was used to generate perfusion color maps, on which we drown ROI on normal bowel and on pathological segment, thus obtaining related perfusion parameters: relative arterial, venous, and late enhancement (RAE, RVE, and RLE), maximum enhancement (ME), and time to peak (TTP). Results Quantitative perfusion analysis showed a good correlation with local degree of Crohn's inflammation activity. Twenty-nine out of 37 patients showed active inflammatory disease (reference standard of active disease: wall bowel thickness and layered enhancement) with following perfusion parameters: REA (%) = 116.1, RVE (%) = 125.3, RLE (%) = 127.1, ME (%) = 1054.7, TTP (sec) = 157. The same parameters calculated in patients with mural fibrosis were as follows: RAE (%): median = 56.4; RVE (%): 81.2; RLE (%): 85.4; ME (%):809.6; TTP (sec): 203.4. A significant difference (p < 0.001) between inflamed and fibrotic bowel wall vascularity, regarding all perfusion parameters evaluated, was found, with higher values in active CD localizations. Conclusion Vascular assessment of perfusion kinetics of bowel wall by dynamic contrast perfusion-MR analysis may represent a complementary diagnostic tool that enables a quantitative evaluation of local inflammation activity in CD patients.
Highlights
In management of Crohn’s disease (CD) patients, to assess the extent, severity and grade of activity is crucial for guiding therapeutic strategies.symptoms related to acute in ammation can bene t from anti-in ammatory drugs, while brosis, which is an irreversible result of chronic in ammation correlated with collagen deposition, causes a xed luminal narrowing, is unresponsive to medical treatment, and requires mechanical intervention such as balloon dilation or stricturoplasty, or surgical resection [1, 2]
Vascular biology has demonstrated the important relationship between neoangiogenesis and CD activity stages: it has been observed that acute inflammation is strictly correlated with an increase of vascular perfusion, while the advanced chronic stage is related to deposition of fibrotic tissue due to a decrease of vascularization, resulting in a reduction of tissue perfusion [5, 6]
E assessment of tissue perfusion, which is strictly related to neoangiogenesis, can be evaluated in vivo, thanks to dynamic contrast-enhanced MR (DCE-MR), that provides quantitative and semiquantitative measurements of tissues blood flow, by the acquisition of series of T1-weighted images before, during and after contrast material injection. is technique allows the evaluation of enhancement as a function of time and, to calculate several quantitative parameters related to functional tissues’ perfusion aspects
Summary
In management of Crohn’s disease (CD) patients, to assess the extent, severity and grade of activity is crucial for guiding therapeutic strategies.symptoms related to acute in ammation can bene t from anti-in ammatory drugs (such as corticosteroids, aminosalicylate, and immunomodulatory drugs), while brosis, which is an irreversible result of chronic in ammation correlated with collagen deposition, causes a xed luminal narrowing, is unresponsive to medical treatment, and requires mechanical intervention such as balloon dilation or stricturoplasty, or surgical resection [1, 2]. Contrast Media & Molecular Imaging is invasive and cannot evaluate the deeper bowel layers where collagen deposition may occur; video capsule does not provide histological sampling and is contraindicated in patients with suspected obstruction; CDAI (Crohn’s disease activity index) includes subjective parameters such as pain, it is complex and time demanding, and serum markers do not completely correlate with disease activity [2, 4]. E assessment of tissue perfusion, which is strictly related to neoangiogenesis, can be evaluated in vivo, thanks to dynamic contrast-enhanced MR (DCE-MR), that provides quantitative and semiquantitative measurements of tissues blood flow, by the acquisition of series of T1-weighted images before, during and after contrast material injection. E assessment of tissue perfusion, which is strictly related to neoangiogenesis, can be evaluated in vivo, thanks to dynamic contrast-enhanced MR (DCE-MR), that provides quantitative and semiquantitative measurements of tissues blood flow, by the acquisition of series of T1-weighted images before, during and after contrast material injection. is technique allows the evaluation of enhancement as a function of time and, to calculate several quantitative parameters related to functional tissues’ perfusion aspects.
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