Magnetic resonance Imaging techniques in patients with Refractory Critical Limb ischemia

Patients with end-stage ischemic limb disease undergoing acute below knee
amputation are most often condemned to a wheel chair leading to a significant
impairment of physical fitness and quality of life. Instead of treating these
frail elderlies in a very conservative manner leading to physical
deterioration, we are now able to achieve immediate walking after amputation
with a primary osseointegration prosthesis. Although large in number, limb loss
due to refractory critical limb ischemia is always considered a
contraindication for this osseointegration procedure as the lack of
vascularization may cause (a)septic loosening of the implant. There is no
scientific evidence that refractory critical limb ischemia is a strict
contraindication for an bone anchored osseointegration prosthesis. Recently a
study was published about save and successful implantation of osseointegration
prosthesis in five below knee amputees with refractory critical limb ischemia.
The estimated chance of primary wound healing after a below knee amputation in
a patient with refractory critical limb ischemia is an important condition for
the implantation of an osseointegration prosthesis. To date an accurate
predictor for successful primary wound healing after below-knee amputation is
lacking.
In this study, we will compare three predictors for successful primary
wound healing after below-knee amputation. These predictors are measures for
lower limb tissue blood perfusion: 1. transcutaneous oxygen measurement
(tcPO2), 2. Blood Oxygenation Level-Dependent (BOLD) MRI and 3. dynamic
contrast-enhanced (DCE) MRI. The results of this explorative study will be used
for a subsequent clinical trial in which the value of tcPO2, BOLD MRI and/or
DCE MRI will be evaluated in what manner these predictors are useful to predict
primary wound healing after below knee amputation and direct implantation of an
osseointegration prosthesis in patients with refractory critical limb ischemia.

A study to explore three different diagnostic tools (predictors) (tcPO2
measurement, BOLD MRI and DCE MRI) quantifying the degree of tissue perfusion
and oxygenation at the intended amputation level in patients with refractory
critical limb ischemia. The techniques will be compared with regard to signal
to noise ratio, interobserver variability and discriminatory ability.

Explorative MR imaging study of approximately 3 months. Transcutaneous oxygen
pressure measurements are performed on all subjects. Perfusion measurements are
performed on all subjects with two different techniques: BOLD MRI and DCE MRI.

The burden for participants in this study will be between 45 and 60 minutes for
the measurements of tcPO2 and MRI imaging procedures. Despite the exclusion of
patients who cannot lie still for 15 minutes (time for each MRI sequence) in
case of rest pain, some patients may experience some discomfort related to rest
pain during cuff inflation. Patients can abort and withdraw at any time during
the MR procedure.
For the DCE-MRI an intravenous drip with contrast is used with the
following possible complications:

• Low possibility of complications due to the intravenous drip are: infection,
phlebitis and thrombophlebitis, emboli, pain, haematoma or haemorrhage,
extravasation, arterial cannulation.
• Low possibility of complications due to the contrast agent are: Headache,
nausea, vomiting, feeling unwell, dizziness, abnormal or unpleasant taste in
your mouth, feeling hot, numbness or tingly feeling, itching or rash, skin
redness, injection site reactions.