Crohn's disease Activity: Abdominal Computed Tomography Histopathology Correlation.

PURPOSE: Crohn's disease is a type of inflammatory bowel disease affecting estimated 4 million people worldwide. Therapy stratification of Crohn's disease (CD) is mainly based on the inflammatory activity being assessed by endoscopic biopsy and clinical criteria. Cross-sectional imaging allows for the assessment of structural characteristics of the entire gastrointestinal tract including small bowel loops and may provide potential non-invasive image-based biomarkers for the inflammatory activity of CD. The aim of this study was to explore the predictive value of Computed Tomography-based morphologic patterns for inflammatory activity in CD. MATERIAL AND METHODS: 42 patients diagnosed with CD were included in a retrospective study (13 male, 29 female, median age 32 years). Abdominal CT imaging was carried out on symptomatic patients at a single institution 0-10 days prior to endoscopic biopsy or surgery using a protocol optimized for the characterization of structural bowel alterations. Image data were initially reviewed independently by three radiologists and discrepancies were settled in consensus with a focus on mesenteric fat stranding and combing, mesenteric adenopathy, mesenteric abscess, intraperitoneal free fluid, fistula, skip lesions, highest wall thickness and the localization of the affected bowel. The extent of inflammatory activity in the bowel wall was determined subsequently by histological analysis. RESULTS: All intestinal and extraintestinal CT findings except the mesenteric comb sign showed a tendency towards higher extent or prevalence in patients with high histological inflammatory activity score, especially median bowel wall thickness (6.0 mm vs. 3.5 mm), mesenteric abscesses (32% vs. 0%) and mesenteric adenopathy (94% vs. 45%). Spearman rank order correlation coefficient indicated a significant correlation of bowel wall thickness (r = 0.40, p < 0.05), mesenteric adenopathy (r = 0.54, p < 0.05), mesenteric abscess (r = 0.33, p < 0.05) and mesenteric fat stranding (r = 0.33, p < 0.05) with the histological inflammatory activity score. CONCLUSION: CT-based biomarkers including wall thickness, mesenteric fat stranding, mesenteric lymphadenopathy and mesenteric abscess positively correlated with the histological inflammatory activity score and therefore provided additional information for therapy stratification in symptomatic patients with CD, particularly as most of these biomarkers are hidden from endoscopy.

MR imaging features for improved diagnosis of hepatocellular carcinoma in the non-cirrhotic liver: Multi-center evaluation.

PURPOSE: To determine MR-imaging features for the differentiation between hepatocellular carcinoma (HCC) and benign hepatocellular tumors in the non-cirrhotic liver. MATERIAL AND METHODS: 107 consecutive patients without liver cirrhosis (46 male; 45 ± 14 years) who underwent liver resection due to suspicion of HCC were included in this multi-center study. The following imaging features were assessed: lesion diameter and demarcation, satellite-lesions, central-scar, capsule, fat-content, hemorrhage, vein-infiltration and signal-intensity (SI) on native T1-, T2- and dynamic-enhanced T1-weighted images (center versus periphery). In addition, contrast-media (CM) uptake in the liver specific phase was analyzed in a sub-group of 42 patients. RESULTS: Significant differences between HCC (n=55) and benign lesions (n=52) were shown for native T1-, T2- and dynamic-enhanced T1-SI, fat-content, and satellite-lesions (all, P<.05). Independent predictors for HCC were T1-hypointensity (odds-ratio, 4.81), T2-hypo-/hyperintensity (5.07), lack of central tumor-enhancement (3.36), and satellite-lesions (5.78; all P<0.05). Sensitivity and specificity of HCC was 91% and 75% respectively for two out-of four independent predictors, whereas specificity reached 98% for all four predictors. Sub-analysis, showed significant differences in liver specific CM uptake between HCC (n=18) and benign lesions (n=24; P<0.001) and revealed lack of liver specific CM uptake (odds-ratio, 2.7) as additional independent feature for diagnosis of HCC. CONCLUSION: Independent MRI features indicating HCC are T1-hypointensity, T2-hypo- or hyperintensity, lack of central tumor-enhancement, presence of satellite-lesions and lack of liver specific CM-uptake. These features may have the potential to improve the diagnosis of HCC in the non-cirrhotic liver.

Quantitative in vivo analysis of small bowel motility using MRI examinations in mice--proof of concept study.

Small bowel motility analyses using magnetic resonance imaging (MRI) could reduce current invasive techniques in animal studies and comply with the 'three Rs' rule for human animal experimentation. Thus we investigated the feasibility of in vivo small bowel motility analyses in mice using dynamic MRI acquisitions. All experimental procedures were approved by the institutional animal care committee. Six C57BL/6 mice underwent MRI without additional preparation after isoflurane anaesthetization in the prone position on a 4.7 T small animal imager equipped with a linear polarized hydrogen birdcage whole-body mouse coil. Motility was assessed using a true fast imaging in a steady precession sequence in the coronal orientation (acquisition time per slice 512 ms, in-plane resolution 234 × 234 µm, matrix size 128 × 128, slice thickness 1 mm) over 30 s corresponding to 60 acquisitions. Motility was manually assessed measuring the small bowel diameter change over time. The resulting motility curves were analysed for the following parameters: contraction frequency per minute (cpm), maximal contraction amplitude (maximum to minimum [mm]), luminal diameter (mm) and luminal occlusion rate. Small bowel motility quantification was found to be possible in all animals with a mean small bowel contraction frequency of 10.67 cpm (SD ± 3.84), a mean amplitude of the contractions of 1.33 mm (SD ± 0.43) and a mean luminal diameter of 1.37 mm (SD ± 0.42). The mean luminal occlusion rate was 1.044 (SD ± 0.45%/100). The mean duration needed for a single motility assessment was 185 s (SD ± 54.02). Thus our study demonstrated the feasibility of an easy and time-sparing functional assessment for in vivo small bowel motility analyses in mice. This could improve the development of small animal models of intestinal diseases and provide a method similar to clinical MR examinations that is in concordance with the 'three Rs' for humane animal experimentation.

Software-assisted quantitative analysis of small bowel motility compared to manual measurements.

AIM: To validate a newly developed software prototype that automatically analyses small bowel motility by comparing it directly with manual measurement. MATERIAL AND METHODS: Forty-five patients with clinical indication for small bowel magnetic resonance imaging (MRI) were retrospectively included in this institutional review board-approved study. MRI was performed using a 1.5 T system following a standard MR-enterography protocol. Small bowel motility parameters (contractions-per-minute, luminal diameter, amplitude) were measured three times each in identical segments using the manual and the semiautomatic software-assisted method. The methods were compared for agreement, repeatability, and time needed for each measurement. All parameters were compared between the methods. RESULTS: A total of 91 small-bowel segments were analysed. No significant intra-individual difference (p > 0.05) was found for peristaltic frequencies between the methods (mean: 4.14/min manual; 4.22/min software-assisted). Amplitudes (5.14 mm; 5.57 mm) and mean lumen diameters (17.39 mm; 14.68) differed due to systematic differences in the definition of the bowel wall. Mean duration of single measurement was significantly (p < 0.01) shorter with the software (6.25 min; 1.30 min). The scattering of repeated measurements was significantly (p < 0.05) lower using the software. CONCLUSION: The software-assisted method accomplished highly reliable, fast and accurate measurement of small bowel motility. Measurement precision and duration differed significantly between the two methods in favour of the software-assisted technique.

Gadoxetate uptake as a possible marker of hepatocyte damage after liver resection-preliminary data.

AIM: To determine the feasibility of evaluating surgically induced hepatocyte damage using gadoxetate disodium (Gd-EOB-DTPA) as a marker for viable hepatocytes at magnetic resonance imaging (MRI) after liver resection. MATERIAL AND METHODS: Fifteen patients were prospectively enrolled in this institutional review board-approved study prior to elective liver resection after informed consent. Three Tesla MRI was performed 3-7 days after surgery. Three-dimensional (3D) T1-weighted (W) volumetric interpolated breath-hold gradient echo (VIBE) sequences covering the liver were acquired before and 20 min after Gd-EOB-DTPA administration. The signal-to-noise ratio (SNR) was used to compare the uptake of Gd-EOB-DTPA in healthy liver tissue and in liver tissue adjacent to the resection border applying paired Student's t-test. Correlations with potential influencing factors (blood loss, duration of intervention, age, pre-existing liver diseases, postoperative change of resection surface) were calculated using Pearson's correlation coefficient. RESULTS: Before Gd-EOB-DTPA administration the SNR did not differ significantly (p = 0.052) between healthy liver tissue adjacent to untouched liver borders [59.55 ± 25.46 (SD)] and the liver tissue compartment close to the resection surface (63.31 ± 27.24). During the hepatocyte-specific phase, the surgical site showed a significantly (p = 0.04) lower SNR (69.44 ± 24.23) compared to the healthy site (78.45 ± 27.71). Dynamic analyses revealed a significantly lower increase (p = 0.008) in signal intensity in the healthy tissue compared to the resection border compartment. CONCLUSION: EOB-DTPA-enhanced MRI may have the potential to be an effective non-invasive tool for detecting hepatocyte damage after liver resection.

Differentiation between active and chronic Crohn's disease using MRI small-bowel motility examinations - initial experience.

AIM: To evaluate the influence of locally active Crohn's disease on systemic small-bowel motility in patients with chronic Crohn's disease compared to healthy individuals. MATERIAL AND METHODS: Fifteen healthy individuals (11 men, four women; mean age 37 years) and 20 patients with histopathologically proven active (n = 15; 10 women, 5 men; mean age 45 years) or chronic (n = 5; four women, one man; mean age 48 years) Crohn's disease were included in this institutional review board-approved, retrospective study. Magnetic resonance imaging (MRI; 1.5 T) was performed after standardized preparation. Two-dimensional (2D) cine sequences for motility acquisition were performed in apnoea (27 s). Motility assessment was performed using dedicated software in three randomly chosen areas of the small-bowel outside known Crohn's disease-affected hotspots. The main quantitative characteristics (frequency, amplitude, occlusion rate) were compared using Student's t-test and one-way analysis of variance (ANOVA). RESULTS: Three randomly chosen segments were analysed in each participant. Patients with active Crohn's disease had significantly (p < 0.05) reduced contraction frequencies (active Crohn's disease: 2.86/min; chronic: 4.14/min; healthy: 4.53/min) and luminal occlusion rates (active: 0.43; chronic: 0.70; healthy: 0.73) compared to healthy individuals and patients with chronic Crohn's disease. Contraction amplitudes were significantly reduced during active Crohn's disease (6.71 mm) compared to healthy participants (10.14 mm), but this only reached borderline significance in comparison to chronic Crohn's disease (8.87 mm). Mean bowel lumen diameter was significantly (p = 0.04) higher in patients with active Crohn's disease (16.91 mm) compared to healthy participants (14.79 mm) but not in comparison to patients with chronic Crohn's disease (13.68). CONCLUSION: The findings of the present study suggest that local inflammatory activity of small-bowel segments in patients with active Crohn's disease alters small-bowel motility in distant, non-affected segments. The motility patterns revealed reduced contraction-wave frequencies, amplitudes, and decreased luminal occlusion rates. Thus evaluation of these characteristics potentially helps to differentiate between chronic and active Crohn's disease.

MR imaging in Crohn's disease: correlation of MR motility measurement with histopathology in the terminal ileum.

BACKGROUND: The objective of the study was to correlate MR-detectable motility alterations of the terminal ileum with biopsy-documented active and chronic changes in Crohn's disease. METHODS: This IRB approved retrospective analysis of 43 patients included magnetic resonance enterography (MRE) and terminal ileum biopsies (<2 weeks apart). Motility was measured at the terminal ileum using coronal 2D trueFISP pulse sequences (1.5T MRI,TR 83.8,TE1.89) and dedicated motility assessment software. Motility grading (hypermotility, normal, hypomotility, complete arrest) was agreed by two experienced readers. Motility was compared and correlated with histopathology using two-tailed Kruskal-Wallis test and paired Spearman Rank-Order Correlation tests. KEY RESULTS: Motility abnormalities were present in 27/43 patients: nine hypomotility and 18 complete arrest. Active disease was diagnosed on 15 biopsies: eight moderate and seven severe inflammatory activity. Chronic changes were diagnosed on 17 biopsies: 13 moderate and four severe cases. In four patients with normal motility alterations on histopathology were diagnosed. Histopathology correlated with presence (P = 0.0056 for hypomotility and P = 0.0119 for complete arrest) and grade (P < 0.0001; P = 0.0004) of motility alterations. A significant difference in the motility was observed in patients with active or chronic CD compared with patients without disease (P < 0.001; P = 0.0024). CONCLUSIONS & INFERENCES: MR-detectable motility changes of the terminal ileum correlate with histopathological findings both in active and chronic CD. Motility changes may indicate the presence pathology, but do not allow differentiation of active and chronic disease.

Crohn's disease: small bowel motility impairment correlates with inflammatory-related markers C-reactive protein and calprotectin.

BACKGROUND: To evaluate the correlation between the levels of C-reactive protein (CRP), calprotectin, and small bowel motility in patients with Crohn's disease assessed with MRI. METHODS: This prospective institutional review board approved study included magnetic resonance imaging enterography (MRE) and analyses of inflammatory markers in blood (C-reactive protein) and feces (calprotectin). For cine MRE, a coronal 2D-T2w sequence was used on a 1.5 T MRI system. Small bowel motility was analyzed in 13 patients using dedicated magnetic resonance MR-motility assessment software (Motasso). Contraction frequency, amplitude, amplitude diameter ratio, and luminal diameter were determined as well as the blood levels of CRP (mg L(-1) ) and fecal levels of calprotectin (ug g(-1) ). Statistics were calculated using Pearson's correlation coefficient. KEY RESULTS: A significant inverse linear correlation was found between the contraction frequency and both the level of CRP (r = -0.701, P = 0.008) and calprotectin (r = -0.805, P = 0.001). Dilatation of small bowel diameter significantly correlated with calprotectin levels (r = 0.857, P =< 0.001) but not with CRP (r = 0.447, P = 0.126). The absolute amplitude of the contractions did not correlate neither with the level of CRP (r = -0.527, P = 0.064) nor with calprotectin (r = -0.612, P = 0.026). The ratio describing the contraction amplitude relatively to the individual luminal diameter significantly correlated with calprotectin (r = 0.736, P = 0.004) and with CRP (r = 0.577, P = 0.039). CONCLUSIONS & INFERENCES: Alterations of small bowel motility during CD flares significantly correlate with the level of calprotectin and CRP indicating that they represent inflammatory activity.

Non-invasive distension of the small bowel for magnetic-resonance imaging.

Magnetic resonance enteroclysis is a promising technique that allows assessment of the small bowel but needs invasive nasoduodenal intubation. We propose a non-invasive distension method for magnetic-resonance imaging (MRI) in which ispaghula, dissolved in an aqueous solution with meglumine gadoterate taken orally over 4 h forms a viscous hydrogel within the intestinal lumen. MRI results from ten volunteers showed good luminal distension, constant signal homogeneity, optimum demarcation of the bowel content from surrounding tissues, and a low rate of artefacts. Our method permits non-invasive high quality MRI of the small bowel.

Equilibrium-phase MR angiography of the aortoiliac and renal arteries using a blood pool contrast agent.

OBJECTIVE: The purpose of this study was to determine the diagnostic usefulness of a new blood pool contrast agent, NC100150, for assessing the aortoiliac and renal arteries. SUBJECTS AND METHODS: Twenty patients with hemodynamically significant stenosis (> or =50% of luminal diameter) of the iliac or renal arteries or an aortic aneurysm documented by digital subtraction angiography underwent MR angiography at 1.5 T after administration of NC100150. Three-dimensional MR angiographic data sets were collected ill the equilibrium phase. In a prospective analysis, each vascular segment (16 segments per arterial tree) was evaluated. RESULTS: All patients tolerated the NC100150 administration well. Mean contrast-to-noise ratios of the vascular data collected in the equilibrium phase of NC100150 was 3.3+/-15.9. Compared with digital subtraction angiography, the sensitivity and specificity of MR angiography for the renal arteries were 82% and 98%, respectively; for the common iliac arteries, 86% and 97%, respectively; for the external iliac arteries, 80% and 100%, respectively; and for the internal iliac arteries, 71% and 977, respectively. All 83 aneurysmal changes revealed by digital subtraction angiograpy of the aortoiliac arteries were well displayed on the MR angiographic data sets. CONCLUSION: Equilibrium-phase NC 00150-enhanced three-dimensional MR angiography shows high specificity when evaluating the abdominal and pelvic vascular systems, but the attendant venous overlap can limit the assessment of stenosis in renal and pelvic arterial segments.

Temperature mapping of magnetic resonance-guided laser interstitial thermal therapy (LITT) in lymphangiomas of the head and neck.

BACKGROUND AND OBJECTIVE: Lymphangiomas of the tongue and neck are uncommon benign congenital lymphatic tumors. These vascular lesions are difficult to treat, frequently recur, and can cause patients significant morbidity. Treatment may also be complicated by adjacent vital anatomic structures. Magnetic resonance (MR)-controlled laser-induced interstitial thermotherapy (LITT) has been proven to be a noninvasive safe treatment. Real-time monitoring of tissue temperature with thermosensitive sequences allows controlled coagulation necrosis. STUDY DESIGN/MATERIALS AND METHODS: LITT was performed in a lymphangioma specimen ex vivo. In four patients (eight procedures) with lymphangiomas of the tongue and neck, MR-guided LITT was performed with a percutaneous approach in a multiapplicator technique. The laser system consisted of a titanium catheter and a protective catheter. The dome of the fiber end had a diameter of 1.4 mm with an active length of 20 mm. Temperature sensitive sequences were used in a 0.5 T open-configured MR scanner with the proton frequency shift technique to map the spatial and temporal distribution of Nd:YAG laser effects (7 Watts, 30 pulses per second, 10 minutes/location). Postoperative MR follow-up was performed at 1 week and at 3 months. In three patients, partial resection of the tumor was performed 6 months after LITT. RESULTS: In three patients, MR clearly showed a diminished tumor volume. All four patients reported subjective amelioration and in three patients former functional problems, such as speech and swallowing were improved. MR thermometry allowed accurate demarcation of changes by heat and distinction of affected tumor volume (3.0 cm +/- 0.3 cm). The histology of the patients 6 months after LITT showed laser-induced fibrosis of former lymphatic tissue. CONCLUSION: The results suggest that LITT can be performed safely with tissue preserving of vital structures and can be effective in the treatment of deep tumors, such as lymphangiomas. However, given the nature of the lesion, the potential for recurrence exists no matter what modality is chosen.

Three-dimensional contrast-enhanced MRI using an intravascular contrast agent for detection of traumatic intra-abdominal hemorrhage and abdominal parenchymal injuries: an experimental study.

The aim of this study was to compare the performance of 3D MRI in conjunction with an intravascular contrast agent to spiral contrast-enhanced CT, regarding the detection of abdominal parenchymal injuries as well as peritoneal hemorrhage in an animal model. Liver and kidney injuries were created surgically in six female pigs under general anesthesia. All pigs underwent contrast-enhanced spiral CT and 3D MR imaging following administration of an intravascular contrast agent (NC100150 Injection). Two readers rated their confidence independently on MR and CT data sets using a five-point scale for the presence of organ injury and hemoperitoneum. Autopsy findings served as standard of reference. Sensitivity and specificity for MR in detecting hepatic and renal injuries as well as hemoperitoneum was 100%. Computed tomography was less accurate with sensitivity and specificity values of 90 and 94%, respectively. Receiver operating characteristics (ROC) analysis revealed a higher confidence when interpretation was based on MR images. In an animal model 3D MR imaging in conjunction with an intravascular contrast agent proved highly accurate in detecting and localizing parenchymal injuries to the upper abdomen as well as in detecting intraperitoneal blood collections.

MRI of the small and large bowel.

Driven by the improvements in gradient technology, breathhold T1- and T2-weighted imaging of the abdominal structures has become possible. These techniques allow exploitation of the advantages inherent to the MR imaging experiment: unsurpassed soft tissue contrast and multiplanar imaging capabilities. Magnetic resonance imaging of the small and large bowel has thus moved from a hypothetical possibility to a practical reality. This manuscript describes some of the underlying fast imaging techniques for display of the small and large bowel. Furthermore, it discusses the plethora of available oral and rectal contrast agents. Finally, clinical indications for MR of the small and large bowel as well as the rectum are described in light of the available literature. Advantages and disadvantages relative to computed tomography and other imaging techniques are discussed.

Sequential fast 3D MRI following oral ingestion of Gd-DOTA: A new means to assess intestinal transit time.

A magnetic resonance image (MRI)-based method to determine the colonic transit time is described. It is based on the oral ingestion of a single dose of 4 ml Gd-DOTA following an overnight fast and the subsequent acquisition of fast three-dimensional (3D) gradient-echo sequences under apnea conditions. The technique was successfully evaluated in three healthy volunteers. Transit of the contrast agent through the small and large intestines was easily followed. Thus, MRI-based colonic transit time determinations are feasible.

Faecal tagging to avoid colonic cleansing before MRI colonography.

Colonic cleansing is unpleasant and has low acceptance by patients. We show the feasibility of faecal tagging, which obviates the need for colonic cleansing, in conjunction with internal magnetic resonance imaging colonography.