Optimum imaging of chronic pancreatitis

Quantitative Edge Analysis of Pancreatic Margins in Patients with Chronic Pancreatitis: A Correlation with Exocrine Function

BACKGROUND

Many efforts have been made to improve accuracy and sensitivity in diagnosing chronic pancreatitis (CP), obtaining quantitative assessments related to functional data. Our purpose was to correlate a computer-assisted analysis of pancreatic morphology, focusing on glandular margins, with exocrine function-measured by fecal elastase values-in chronic pancreatitis patients.

METHODS

We retrospectively reviewed chronic pancreatitis patients who underwent fecal elastase assessment and abdominal MRI in our institute within 1 year. We identified 123 patients divided into three groups based on the fecal elastase value: group A with fecal elastase > 200 μg/g; group B with fecal elastase between 100 and 200 μg/g; and group C with fecal elastase < 100 μg/g. Computer-assisted quantitative edge analysis of pancreatic margins was made on non-contrast-enhanced water-only Dixon T1-weighted images, obtaining the pancreatic margin score (PMS). PMS values were compared across groups using a Kruskal-Wallis test and the correlation between PMS and fecal elastase values was tested with the Spearman's test.

RESULTS

A significant difference in PMS was observed between the three groups (p < 0.0001), with a significant correlation between PMS and elastase values (r = 0.6080).

CONCLUSIONS

Quantitative edge analysis may stratify chronic pancreatitis patients according to the degree of exocrine insufficiency, potentially contributing to the morphological and functional staging of this pathology.

Deployable ultrasound applicators for endoluminal delivery of volumetric hyperthermia

PURPOSE

To investigate the design of an endoluminal deployable ultrasound applicator for delivering volumetric hyperthermia to deep tissue sites as a possible adjunct to radiation and chemotherapy.

METHOD

This study considers an ultrasound applicator consisting of two tubular transducers situated at the end of a catheter assembly, encased within a distensible conical shaped balloon-based reflector that redirects acoustic energy distally into the tissue. The applicator assembly can be inserted endoluminally or laparoscopically in a compact form and expanded after delivery to the target site. Comprehensive acoustic and biothermal simulations and parametric studies were employed in generalized 3D and patient-specific pancreatic head and body tumor models to characterize the acoustic performance and evaluate heating capabilities of the applicator by investigating the device at a range of operating frequencies, tissue acoustic and thermal properties, transducer configurations, power modulation, applicator positioning, and by analyzing the resultant 40, 41, and 43 °C isothermal volumes and penetration depth of the heating volume. Intensity distributions and volumetric temperature contours were calculated to define moderate hyperthermia boundaries.

RESULTS

Parametric studies demonstrated the frequency selection to control volume and depth of therapeutic heating from 62 to 22 cm³ and 4 to 2.6 cm as frequency ranges from 1 MHz to 4.7 MHz, respectively. Width of the heating profile tracks closely with the aperture. Water cooling within the reflector balloon was effective in controlling temperature to 37 °C maximum within the luminal wall. Patient-specific studies indicated that applicators with extended OD in the range of 3.6-6.2 cm with 0.5-1 cm long and 1 cm OD transducers can heat volumes of 1.1-7 cm³, 3-26 cm³, and 3.3-37.4 cm³ of pancreatic body and head tumors above 43, 41, and 40 °C, respectively.

CONCLUSION

In silico studies demonstrated the feasibility of combining endoluminal ultrasound with an integrated expandable balloon reflector for delivering volumetric hyperthermia in regions adjacent to body lumens and cavities.

Diagnosis of hilar cholangiocarcinoma using intravoxel incoherent motion diffusion-weighted magnetic resonance imaging

OBJECTIVE

To investigate the value of intravoxel incoherent motion diffusion-weighed magnetic resonance imaging (IVIM-DWI) in discriminating the pathological grades of hilar cholangiocarcinoma (HC).

PATIENTS AND METHODS

Thirty-seven HC patients were enrolled and received routine and advanced DWI scanning with multiple b-values. IVIM-DWI images were obtained using echo-planar imaging sequence.

RESULTS

The consistency of the maximum cross-sectional area ROI measuring method was higher than that of the repeated sampling ROI measuring method. ADC_slow values were closely correlated with the pathological grades of HC. The degrees of biliary dilatation and MELD scores had no influence on the negative correlation between ADC_slow values and the pathological degrees of HC patients.

CONCLUSIONS

ADC_slow values could be applied in indicating the pathological grades of HC, which was independent on the extent of biliary dilatation.