Biomedical Engineering Reference
In-Depth Information
sufficiently promising to warrant further investigation specifically looking at
the differences between estrogen receptor positive (ER + ) and estrogen receptor
negative (ER − ) breast tumours and between invasive and in situ components.
Hence, spectroscopy could be employed to diagnose and type breast cancers.
brain Tumours and Other brain Disorders
Astrocytomas are the most common gliomas, accounting for about half of
all primary brain and spinal cord tumours. Astrocytomas develop from star-
shaped glial cells called astrocytes, part of the supportive tissue of the brain.
They may occur in many parts of the brain, but most commonly in the cere-
brum. They occur less commonly in the spinal cord. People of all ages can
develop astrocytomas, but they are more prevalent in adults, particularly
middle-aged men. In children, most are low-grade tumours, while in adults
most are high-grade tumours. the World Health Organization (WHO) has
established a four-tiered histologic grading guideline for astrocytomas that
assigns a grade from 1 to 4, with 1 being the least aggressive and 4 being
the most aggressive, also known as glioblastoma multiforme (GBM). A com-
puted tomography (CT) or magnetic resonance imaging (MRI) scan is neces-
sary to characterise the extent of these tumours (size, location, consistency).
However, these techniques will not distinguish astrocytomas from lesions
due to other causes and a neurosurgical biopsy is required for confirmation
of diagnosis, which is not always feasible.
Studies have shown that proton MR spectroscopy readily distinguishes nor-
mal brain tissues from astrocytomas [5-7]. Some investigators have proposed
that the presence of lactate correlates with a higher degree of malignancy and
that it is commonly observed in glioblastoma multiforme [8,9]. Proton MR
spectroscopy may also be used to distinguish infection from a tumour [10].
However, proton MR spectroscopy may not be able to distinguish between
different histologic grades of malignancy in astrocytomas [11]. Vibrational
spectroscopy may provide additional information by differentiating between
the histologic grades of astrocytomas, and hence could be more precise in
diagnosis. Vibrational spectroscopy, like proton MR spectroscopy, may also
play a role in monitoring the response of astrocytomas to treatment [8].
As with proton MR spectroscopy, vibrational spectroscopy may also be
useful in the diagnosis of difficult cases of meningiomas as lactate and ala-
nine may be elevated in some meningiomas, which can be detected with this
technique [12]. Meningiomas are tumours that grow from the meninges, the
layers of tissue covering the brain and spinal cord.
alzheimer's Disease
Biochemically, Alzheimer's disease is characterised by decreased cortical
acetylcholine caused by a loss of cholinergic cells that are critical for nor-
mal memory and cognition. The clinical manifestations of the disease may
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