Diagnosing cerebral vasculitis using MR intracranial vessel wall imaging at 7.0 tesla

The cerebral vasculitides are a heterogeneous group of diseases. Early
diagnostic discrimination between the cerebral vasculitides and other vessel
wall diseases (vasculopathies) is, however, essential since they can have
devastating consequences, often in relatively young patients, if not promptly
and adequately treated.

After exclusion of non-inflammatory or cardiac embolic causes of stroke by
extracranial and intracranial vessel assessment and cardiac investigations, an
accurate diagnosis remains challenging due to limited sensitivity and
specificity of different diagnostic modalities like Magnetic Resonance Imaging
(MRI), Cerebrospinal Fluid (CSF) examination, angiography, and brain biopsy1, 2
for the diagnosis of cerebral vasculitis.

A diagnostic test with excellent properties for visualising the intracranial
vessel wall could help making a correct and early diagnosis of cerebral
vasculitis. Therefore, in the current study, we will develop a non-invasive
method for the detection of cerebral vasculitis. Based upon the intracranial
vessel wall sequence, developed by the 7T group and used in an on-going study
(IVI study), a 7.0 tesla MR protocol will be developed and optimized for the
visualization of the intracranial arterial wall in patients suspected of
cerebral vasculitis. With our protocol we will be able to visualize both normal
intracranial vessel wall as well as vessel wall abnormalities. Together with
the IVI-study and the PIVI-study, in which the intracranial causes of ischemic
stroke of the anterior and posterior circulation, respectively, will be
assessed, this study will provide better insight in the underlying pathological
vessel wall changes in a large group of neurological patients.

The main research question is to compare the diagnostic accuracy of 7T MRI for
cerebral vasculitis, with the standard diagnostic practice (SDP). The true
nature of the disease will be assessed for all patients at the end of the study
by re-evaluation of the patients, assessing either response to treatment or
recurrent symptoms (Reference standard, RS). The goal of the study is to
compare both the sensitivities and specificities of the two diagnostic tests.

This study is designed as a single-center prospective case-control study.
Intracranial vessel wall imaging will be performed with a 7T MRI scanner in
patients suspected of cerebral vasculitis and healthy controls, combined with
standard clinical imaging of the brain.

Baseline characteristics of all patients and healthy controls will be collected
during inclusion into our study. The first 7T MRI exams in patients will be
acquired during the symptomatic phase and before start of treatment for
vasculitis (if applicable); the second 7T MRI exams will be performed after 6
months. Both the neurologist and radiologist (blinded for clinical status) will
give a diagnoses to every individual patient based upon the standard clinical
work-up or the 7T scan, respectively. This will be done at baseline and after 6
months. The 6 months scan and clinical work-up will allow them to assess the
true nature of the disease and compare the sensitivity and specificity of the
7T MRI to that of the standard clinical work-up. The change in aspect of (one
of) the artery (arteries) of the cerebral circulation after 6 months will allow
a detailed assessment of the underlying cause of the disease, as well as
possible changes due to received treatment (if applicable). The healthy
controls will receive only one 7T MRI exam. Blood samples of all patients will
be taken (if not already done for clinical purposes) to verify the absence of
renal dysfunction. Healthy volunteers will be asked for known renal impairment.
All patients will have their regular clinical work-up and treatment,
independent of this study or its results.

We aim at a yearly inclusion of 15-20 patients suspected of all forms of
cerebral vasculitis. With this inclusion rate, 40 patients will be included in
3 years. An additional 40 healthy volunteers will be included during the three
years of inclusion.

During the MRI, patients are exposed to strong magnetic fields and radio waves.
In normal clinical practice, MRI is very often used. There are no harmful
effects on the human body determined. In some cases, people experience flashes
of light, tingling and transient dizziness. These are always during the scan
and disappear immediately after scanning. Implanted medical devices might
become disturbed by the magnetic field. People with medical implants are
therefore not considered for the study.

The gadolinium contrast agent is widely used for MR imaging exams in the
clinical setting, and as such it is administered to thousands of patients every
year in our hospital. In some cases, an allergic reaction may occur. This
creates itching and nausea with possible red bumps on the skin. Almost always,
these symptoms disappear after the examination. It is seldom that medical
treatment is necessary. At all times, there will be a doctor present as the
contrast agent is administered. Patients with a known allergy to the contrast
agent gadolinium can not participate in this study.

If patients have renal problems, they can not participate in this study. During
their hospitalization some blood is usually taken by which we can determine
whether they have kidney problems. If this is not the case, a blood sample
will be taken, before the first MRI scan, for this study.