CASE 982 Published on 20.03.2001

Teaching Case

Section

Neuroradiology

Case Type

Clinical Cases

Authors

R.N.Sener, S.Dzelzite, A.Migals, U.Raits, A.A.Veinbergs

Patient

53 years, male

Categories

No Area of Interest ; Imaging Technique MR, MR-Functional imaging ;

No Procedure ; No Special Focus ;

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Clinical History

Increased intracranial pressure

Differential Diagnosis List

Metastatic adenocarcinoma

Imaging Findings

Presented with signs and symptoms increased intracranial pressure. On MRI, T1 and T2-weighted images, T1-weighted images after contrast medium, and echo-planar diffusion images were acquired.

Discussion

The most common primary tumors to metastasize to brain include lung, breast, malignant melanoma, genitourinary, and gastrointestinal tumors, and the posterior fossa is a common site. On diffusion MRI most solid tumors are isointense to brain parenchyma on true diffusion (b=1000 sec/mm2) images, and reveal high signal on apparent diffusion coefficient (ADC) maps, reflecting increased motion of water molecules. On the other hand, tumors with relatively high nuclear to cytoplasmic ratios (like meningiomas) tend to be hyperintense on true diffusion (b=1000 sec/mm2) images. They have low signal, and low ADC values on the ADC maps, consistent with relative restriction of movement of water molecules. This was true for the current patient with metastatic lung tumor.

References

[1] Okamoto K, Ito J, Ishikawa K, Sakai K, Tokiguchi S.
Diffusion-weighted echo-planar MR imaging in differential diagnosis of brain tumors and tumor-like conditions.
Eur Radiol. 2000;10(8):1342-50. (PMID: 10939505)

[2] Filippi CG, Edgar MA, Ulug AM, Prowda JC, Heier LA, Zimmerman RD. Appearance of meningiomas on diffusion-weighted images: correlating diffusion constants with histopathologic findings. AJNR Am J Neuroradiol. 2001;22(1): 65-72. (PMID: 11158890)

[3] Sugahara T, Korogi Y, Kochi M, Ikushima I, Shigematu Y, Hirai T, Okuda T, Liang L, Ge Y, Komohara Y, Ushio Y, Takahashi M. Usefulness of diffusion-weighted MRI with echo-planar technique in the evaluation of cellularity in gliomas.
J Magn Reson Imaging. 1999 Jan;9(1):53-60. (PMID: 10030650)

[4] Sener RN. Diffusion MRI: apparent diffusion coefficient (ADC) values in the normal brain, and a classification of brain disorders based on ADC values. Comput Med Imaging Graph (2001, in press).

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