What are different of MRI findings in malignant spinal lesion
and spinal infection in King Chulalongkorn Memorial Hospital?
By:
Wichet Piyawong, MD.*
Advisor:
Asst. Prof. Sukalaya Lerdlum, MD, MSc.*
Co-advisor: Ekapol Sethsakol, MD.*
*Department of Radiology
Faculty of Medicine, Chulalongkorn University
Bangkok, Thailand
Abstract:
PURPOSE: The aim of this study was to describe MRI findings to differentiate
between malignant spinal lesion and spinal infection.
MATERAILS AND METHODS: We retrospectively reviewed MRI of the spine
that pathological records or medical recorded matching with malignant spinal
lesion and spinal infection from January 2002 to December 2005 in King
Chulalongkorn Memorial Hospital. Thirty five patients, 13 of spinal infection
and 22 of malignant spinal tumor were included. Spinal MRI of the patients
proven to be post operation were excluded.
RESULTS: The finding on MR imaging of 13 patients with spinal infection and
22 patients with malignant spinal tumor were compared. Spinal infections
involved one to 5 vertebrae, usually 2 vertebrae (10/13, 77%) but malignant
spinal tumor involved one to 7 vertebrae, usually more than 2 vertebrae (14/22,
64%). The posterior elements were involved in 16/22 (73%) patients with
malignancy and about 8/13 (62%) patients with infection. The intervertebral
discs were involved in 12/13 (92%) with infection but none with malignancy.
The endplates were involved about 12/13 (92%) and 1/22 (4%) in spinal
infection and malignant spinal tumor, respectively. The signal intensity of the
both infectious and malignant lesions were increased to a variable degree on
T2-weighted images. None of all patients with spondylitis present with low
signal intensity on T2-weighted images. The patients with a low signal intensity
and intermediate signal intensity on T2-weighted images were seen in
anaplastic plasmacytoma and HIV with leiomyosarcoma, respectively.
CONCLUSION: Spinal infections usually reveal vertebral endplate involvement
located adjacent to the intervertebral disc with loss of vertebral endplate
definition and usually involvement of contiguous vertebrae. Both malignant
tumor and infectious involvement of bone marrow revealed decreased signal
intensity on T1-weighted images and increased signal intensity on T2weighted images. Malignant spinal tumor was differentiated from osteomyelitis
by lack of disc involvement with tumor cells. The disc outline in osteomyelitis
was usually irregular and disc intensity was increased on T2-weighted images.
There is vertebral body and together with posterior element involvement with
infection disease that must differentiated with spinal tumor. The suggested
clue that can help differentiate between malignant spinal lesion and spinal
infection are associated findings such as the endplate and disc involvements
that mostly found in spinal infection.
Keywords: spinal infection, malignant spinal tumor, Magnetic Resonance
Image (MRI).