The diagnostic value of three detection techniques of ultrasound in the active stage of Crohn's disease.

OBJECTIVE: The widespread availability of Ultrasound machines and their relatively low cost and functionality make them an attractive tool to use during the treatment of ongoing Crohn's Disease (CD). This study aims at exploring the value of conventional, power Doppler and contrast-enhanced ultrasound during the active stages of CD. PATIENTS AND METHODS: 24 patients in the active stages of Crohn's disease were enrolled in the study. The full, medial and lateral intestinal wall thicknesses and the thickness ratio of medial to lateral intestinal wall of the segmental lesions were measured by conventional ultrasound. The diseased intestinal wall was also examined by power Doppler ultrasound to assign Limberg classification types: 3 cases were Limberg II, 9 cases were Limberg III and 12 cases were Limberg IV type. Importantly, the full and medial thicknesses of the intestinal walls with different Limberg types were compared, and statistically significant differences were found (p<0.05). Finally, images of the diseased segments were taken by contrast-enhanced ultrasound, and the contrast agent bolus arrival, the inflow and the peak enhancement times were calculated in order to be able to distinguish intestinal wall thickness differences according to different Limberg types. RESULTS: Cases with Limberg types III and IV mostly showed total intestinal enhancement, while Limberg II type cases showed mostly medial intestinal enhancement. When comparing the inflow and peak times of contrast-enhanced ultrasound of patients with different Limberg types, the differences found were statistically significant (p<0.05). CONCLUSIONS: This study confirms incrassation of the intestinal wall being the main ultrasonic appearance of active CD. Both power and contrast-enhanced ultrasound are effective tools in the management of active CD: while power ultrasound can be used to carry out Limberg typing, contrast-enhanced ultrasound can analyze and diagnose incrassation segments of the intestinal wall with different disease stages.

Reversible, nanometer-scale conductance transitions in an organic complex

Reversible conductance transitions are demonstrated on the molecular scale in a complex of 3-nitrobenzal malononitrile and 1, 4-phenylenediamine, by application of local electric field pulses. Both macroscopic and local current-voltage (I/V) measurements show similar electrical bistability behavior. The mechanism of the electrical bistability is discussed.