Microcirculation and perfusion with contrast enhanced ultrasound (CEUS) in Crohn's disease: First results with linear contrast harmonic imaging (CHI)

Aim: To evaluate a newly introduced high resolution linear transducer for vascularization and mural perfusion assessment using contrast harmonic imaging (CHI) with quantitative time intensity curve analysis (TIC) in patients with active Crohn's disease (CD).

Material and methods: We prospectively evaluated 14 consecutive patients (7 women, 7 males, age range 19–42 years, median 28 years) with histologically proven CD having an acute episode of the disease applying contrast enhanced MRI and high resolution ultrasound. For the ultrasound we used a newly introduced high resolution linear multi-frequency transducer (6–9 MHz, Logiq 9, GE). Ultrasound was performed by an experienced radiologist applying color coded Doppler sonography (CCDS), power Doppler (PD) and contrast enhanced CHI using the ‘true agent detection mode’. Additionally, 5 healthy volunteers were examined by ultrasound applying CCDS, PD and CHI. After the injection of 2.4 ml ultrasound contrast agent (SonoVue) the dynamic CHI cine sequences were recorded as digital raw data for 60 seconds. Therefore we were able to perform a quantitative perfusion analysis using TIC retrospectively. CCDS, PD and CHI with TIC were compared and analyzed.

Results: In all 14 patients MRI showed inflammatory changes in the terminal or pre-terminal ileum. Using PD and CCDS enlarged vessels surrounding the bowel wall were visualized in all patients. PD as well as CCDS diagnosed just in 9 of 14 patients augmented mural vessels. Having CHI with TIC increased mural contrast enhancement was diagnosed in all 14 patients. Patients with CD showed a maximum enhancement 36 s after injection with 9 dB (range 5.9–13.2 dB), while healthy volunteers reached the maximum level of 2.8 dB (range 2–3.8 dB) after 23 s (p<0.05).

Conclusion: Using high resolution linear transducer mural perfusion changes in active Crohn's disease can be appreciated applying CHI with TIC. This technique could be an effective dynamic imaging modality for diagnosis and especially follow-up examination to monitor treatment in CD.