1. Evaluation of experimentally induced early hepatic alveolar echinococcosis in rats with MRI-DWI
Zeng Hongchun，Liu Wenya*
Imaging center, The First affiliated hospital,
Xinjiang medical university, Urumqi, China
Innovation for the Management of Echinococcosis Symposium, Besançon, March 27, 2014

2. Background Early diagnosis Dynamic follow-up
Hepatic Alveolar Echinococcosis (HAE) is a potentially fatal parasitic inflection like malignant disease
Early
diagnosis
The disease remains thus underdiagnosed
It’s like an infectious cancer, so early diagnosis would be vital
Dynamic
follow-up
Chemotherapy with benzimidazoles have increasiongly been used in treatment of AE

3. Imaging method for HAE Us Computed tomography（CT)
Magnetic Resonance Imaging(MRI)
PET-CT
SPECT
Now

4. Technology comparison
PET
SPECT CT MR
Information
Functional
Anatomical
Both
Anatomical Detail
Poor
Good
Excellent
Soft Tissue Differentiation
- - -
Ionizing Radiation
Yes No
Spatial Resolution (clinical)
3-8 mm
8-15 mm
1 mm
Activity of HAE
Poor*

5. Background Staging diagnosis Activity Early MR-DWI
A promising technique for characterizing HAE
Staging
diagnosis
Early
Activity
With recent developments in gradient technol- ogy, multichannel coils, echo-planar sequences, and parallel imaging techniques, diffusion- weighted imaging has become a promising technique for characterizing lesions. Diffusion- weighted imaging exploits the microscopic ran- dom mobility of water protons to measure the diffusion of fluid in tissue (34,37–39).Tissue regions with restricted water diffusion (eg, malig- nant lesions) are displayed as regions of high signal intensity. Signal intensity at diffusion-weighted imaging can be quantified by calculating the apparent diffusion coefficient (ADC), a valuable indicator for the diagnosis and characterization of focal hepatic lesions (34,40,41).The movement of water molecules in malignant tumors, unlike that in alveolar echinococcosis lesions, is restricted because of increased cellularity and reduced ex- tracellular space (42). Alveolar echinococcosis lesions can be reliably identified on diffusion- weighted images obtained with b values of 0, 50, 400, and 800 sec/mm2 and qualitatively assessed on ADC maps. Typically, the lesions appear hypointense on T1-weighted and T2-weighted images, as well as on diffusion-weighted images，obtained with a b value of 800 sec/mm2, which results in a subjectively higher ADC in the lesion than in liver parenchyma (Fig 12). Restricted dif- fusion due to a superinfection (ie, an abscess) may be observed in the necrotic central part of par- ticularly large alveolar echinococcosis lesions.The general lack of diffusion restriction in alveolar echinococcosis lesions is an important finding that helps differentiate them from malignancies that have similar clinical features and imaging findings, including invasion and metastases. Ta- ble 1 summarizes characteristic imaging features that are helpful for diagnosing hepatic alveolar echinococcosis.
Mecit K, et al. RSNA 2012, 2053.

6. ? Diagnosis –Anatomic and Metabolic Imaging of DWI
Application of DWI for HAE
Early diagnose
Differentiation
Follow up
exploit

7. Purpose
To find the best scanning parameter in early detection of HAE infected rats with MR-DWI
Characterizing the features of HAE of rat with MRI-DWI
To verify the value of MRI-DWI in detecting early HAE of rat
Ethics committee approval of a study

8. Material & Methods
The experimentally induced HAE in 40 rats were studied after testified by US
MR-DWI scans(GE 3. 0 T Signa Eexcite)
Routing T1WI and T2WI
DWI obtained with b values of 300~800sec/mm2 with internal 100 sec/mm2
ADC measuring
ROI were placed on the marginal zone, center area of the lesion as well as nearby liver perenchyma,
Avoiding calcification, vessels and bile duct
Follow up: early(9 weeks), middle(28 weeks), late(50weeks)
Pathological exam of removed liver
：ROI were placed on the marginal zone, solid component area of the lesion as well as nearby liver perenchyma

9. Material & Methods Anesthesia and injection MR Scan with wrist coil
Under oper surgery looking
Anesthesia and injection
MR Scan with wrist coil
(GE 3.0T Signa HDx System)

10. (Intermediate and advanced stage)
Results
The detection rate of MR for HAE in rats
HAE
(Early stage)
(Intermediate and advanced stage)
MR-T2WI
82.5% (33/40)
100%(40/40)
MR-DWI(b=500)
MR-DWI(b=700)
77.5%（31/40）
97.5%（39/40）

11. Results MRI-T1\T2 findings of different stage of HAE in rats
Early stage(9 weeks)

12. Results MRI-T1\T2 findings of different stage of HAE in rats
Middle stage (28 weeks)

13. Results MRI-T1\T2 findings of different stage of HAE in rats
Later stage (50 weeks)

14. Results MRI-DWI of different stage of HAE in rats
b value of 500 sec/mm2

15. Results
Macropathology of different stage of HAE in rats

16. Results
Pathological changes of different stage of HAE in rats

17. Normal liver parenchyma
Results
Comparison of ADC value between the marginal zone, center area of the lesion and normal liver parenchyma
Early stage
Middle stage
Later stage
Marginal zone ++ +
Center area
Normal liver parenchyma

18. Results ADC value vs Pathologic features Margin zone
The lower signal surrounding the lesion is the inflammatory belt in early stage, which was rich in micro-blood vessels and fibrotic tissue, as well as inflammatory cells
Fibrosis
ADC value
Areas of low signal intensity of DWI correspond to fibrotic or collagenous components.
DWI
Margin zone
Pathology

19. Results Dynamic presentation of MR imaging of HAE in rats Early stage
Middle stage
Later stage
T1WI
low signal
T2WI
Uniformity high signal
heterogeneous signal intensity
DWI
high signal
Marginal zone:ring lower signal ，lunar halo sign
Marginal zone:
Slightly high signal
High signal
(areas of low and high signal intensity reflect the

20. Summary MR-DWI can be used in rat model of HAE
MRI-DWI can demonstrate the characteristic features of early HAE in animal atudy
ADC value can reflect the fibrosis degree of HAE in rats

21. Thank you for your attention!

22. Author and correspondence address
Zeng Hongchun
TEL: +86–991–