Saturday, May 23, 2009

Mineralizing microangiopathy

Lateral radiograph of 14 year old boy who underwent radiotherapy and chemotherapy for right frontal glioma shows linear tram tack calcification in the frontal region.

CT scan of the same patient showed caorse gyral patternn calcification in the roght frontal region with white matter edema in bilateral frontal lobes.

Mineralizing microangiopathy, a distinctive histopathologic process involving the microvasculature of the central nervous system (CNS), is usually seen following combined radiation and chemotherapy for the treatment of CNS neoplasms in childhood. It represents dystrophic calcification within the brain substance, predominantly involves the basal ganglia and subcortical white matter and is well shown by CT. CT typically demonstrates calcification within the basal ganglia and subcortical white matter. MRI, although less sensitive than CT to calcification, The areas of calcification may give paradoxically increased signal on T1-weighted MRI due to a surface-relaxation mechanism, and decreased signal on T2-weighted images. This should be differentiated from Sturge weber syndrome by the clinical presentation and other imaging findings.

Sunday, May 3, 2009

Periapical cyst (radicular cyst)

Fig a: OPG of 14 year old male with h/o caries tooth shows subtle oval lytic lesion at the apex of root of second molar tooth.
Fig b: Coronal reformatted image shows well defined cystic lesion at the apex of tooth (arrow) and is better demonstrated by the 3D volume rendering image in fig c (arrow). The features are consistant with periapical cyst.

The periapical (radicular) cyst is the most common odontogenic cyst and results from inflammation secondary to caries or other entities. The peak prevalence of this asymptomatic cyst occurs between the fourth and sixth decades of life. Typically, infection spreads to the apex (root) of the tooth, leading to secondary apical periodontitis, granuloma, or abscess and, finally, cyst formation. The cyst appears as a round or pear-shaped, well-defined radiolucent lesion with sclerotic borders. Most periapical cysts are less than 1 cm in diameter. It is important to note that radiology cannot always help distinguish a granuloma from a cyst.

Saturday, May 2, 2009


Ameloblastoma arises from the enamel-forming cells of the odontogenic epithelium that have failed to regress during embryonic development. The tumor most commonly occurs in the posterior mandible, typically in the third molar region, with associated follicular cysts or impacted teeth. The slow growth of the tumor can lead to significant expansion of the mandible. Patients typically present in the third to fifth decades of life with a slow-growing, painless mass. The expansile, radiolucent tumor can be unilocular or multilocular, with a characteristic "soap bubble–like" appearance. CT findings include cystic areas of low attenuation with scattered isoattenuating regions, representative of soft-tissue components. The lesion can also erode through the cortex with extension into the surrounding oral mucosa. In addition, erosion of the roots of adjacent teeth is unique to ameloblastoma and indicates the aggressive behavior of the tumor. However, only histopathologic findings can help determine benignity and the absence of carcinomatous change.

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