Differential Diagnosis of Bright Lesions on Diffusion-weighted MR Images Fahad albadr MD

Acute Infarction Acute ischemic lesions are characterized by high signal intensity on DW images and low ADC values WHAY?

interruption of cerebral blood flow results in rapid (withine minutes) breakdown of energy metabolism and ion exchange pumps

a massive shift of water from the extracellular into the in tracellular compartment (cytotoxic edema)

Acute infarction within the 1st hour

Acute infarction within the first 6 hours after stroke

ADC ADC Values (x 10-3 mm2/sec) of Ischemic Lesions during Different Time Intervals

Most studies report high sensitivity and specificity for DW images and ADC maps in the diagnosis of acute stroke

Venous Stroke

The diffusion findings in human cerebral venous infarction remain controversial

Early stage of cerebral abscess

Tumors: Glioma The signal intensity of gliomas on DW images is variable a subtle hyperintensity is a common nonspecific finding Can the ADC Values Differentiate between Different Grades of Gliomas? Can the DW Images and/or ADC Maps Differentiate between Glioma and Peritumoral Edema?

Glioblastoma multiforme.

Metastasis -the signal intensity of nonnecrotic components of metastases on DW images is variable (generally iso- or hypointense; occasionally hyperintense). -The necrotic components of metastases show a marked signal suppression on DW MR images and increased ADC value

Differential Diagnosis of Ring-enhancing Cerebral Masses The central hypointensity on the DW image and the hyperintensity on the ADC map support the diagnosis of necrotic metastasis.

the signal intensity of nonnecrotic components of metastases on DW images is variable (generally iso- or hypointense, occasionally hyperintense). The necrotic components of metastases show a marked signal suppression on DW images and increased ADC values (may be related to increased free water).

Cerebral metastasis with increased signal intensity on DW images

Tumor cellularity is probably a major determinant of signal intensity of solid components of cerebral metastases on DW images and on ADC values

Meningioma The signal intensity of meningiomas on DW images is variable Most benign meningiomas are isointense on DW images Only 23%of benign meningiomas (three of 13) were slightly hyperintense in the study of Filippi et

Can the DW images and ADC values differentiate between malignant and benign meningiomas?

Lymphoma The enhancing components of lymphomas are generally hyperintense on DW images

Cerebral lymphoma with hyperintense and hypointense components on DW images

Epidermoid cyst

Arachnoid cyst plus meningioma

Abscess

Encephalitis

Hemorrhage