Diffusion lesion

Fig. 3.1a,b. a The ischaemic penumbra. The perfusion (PI) lesion delineates the extent of hypoperfusion and the diffusion (DWI) lesion outlines the infarct core. The difference between the two lesions (perfusion-diffusion mismatch) represents the ischaemic penumbra, tissue at risk of progression to infarction, b Patient imaged at 3 h after onset of left hemiparesis and neglect with large PI (time to peak - TTP) lesion and smaller DWI lesion. At day 3 reperfusion has not occurred and the infarct core (diffusion lesion) has expanded greatly into the region of acute perfusion-diffusion mismatch. This is consistent with the perfusion-diffusion mismatch area representing the ischaemic penumbra... 

Much debate exists over the accuracy of the acute DWI lesion identifying the ischaemic core, that is, tissue that is irreversibly damaged. There is no doubt that diffusion lesions may be partially reversed with early reperfusion. This has been demonstrated in both animal and human stroke (Chalela et al. 2003 Kidwell et al. 2000 Li et al. 1999,2000). However, in humans these lesion reversals in most instances are only minor or partial, and are quite often not permanent. Indeed, in our thrombolytic series, less than 5% of patients had what would be considered any significant reduction in ischaemic lesion volume between the pre-treatment DWI and outcome T2-weighted... 

Fig. 4.12. Mismatch concept of diffusion lesion (smaller) and perfusion deficit (larger) in human territorial brain infarction. Acute MCA territory ischemia/oligemia with a smaller, centrally located diffusion disturbance showing the relationship between infarct core, ischemic penumbra and changes in DWI and PI. DWI, diffusion-weighted imaging PI, perfusion imaging ADC, apparent diffusion coefficient ATP, high energy phosphates MCA, middle cerebral artery...

Fig. 15.6. Computerized registration and overlay of DWI lesions on PI images, to determine the exact location of the diffusion lesion with respect to the perfusion deficit. The alignment of the time-to-peak (TTP) and DWI images demonstrates that the lesions are indeed located in the borderzone area where the extent of the perfusion deficit is most pronounced...

Time Course of Diffusion Lesion Evolution in Acute Stroke... 

OUvot, J.M., et al., Relationships between cerebral perfusion and reversibility of acute diffusion lesions in DEFUSE insights from RADAR. Stroke, 2009. 40(5) p. 1692-7. 

Cryotherapy with liquid nitrogen or carbon dioxide snow is usually efficacious in very mild infestations, but it must be performed for a fair depth beyond the site of progression apparent at the visible lesion. Good results have also been obtained using topical thiabendazole in 10% suspension or 2% in dimethyl-sulfoxide. In cases characterized by diffuse lesions, oral thiabendazole at doses of 20-50 mg/kg/day for 7-10 days may be used (Stromberg and Christie 1976). 

Skin Erythematous psoriasiform skin lesions Large diffuse lesions on limbs and trunk to the midline + +... 

Macroscopically, the liver maybe occupied by solitary mass, multiple masses or a diffuse lesion without... 

EHE usually presents as multiple peripheral hy-poechoic masses. Hyperechoic and mixed hypo-hyperechoic appearances, however, have also been described. The hyperechoic masses may have a peripheral hypoechoic rim. There is no correlation between sonographic pattern and the size of the lesions. In diffuse lesions hyperechoic foci correspond to calcification (Miller et al. 1992). 

In diffuse lesions, unenhanced CT shows large and diffuse areas of overall low attenuation. The vascularity of diffuse lesions is moderate, but delayed fill-in of contrast medium is consistent with fibrosis. 

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