CT Scan with Contrast

I am scheduled to have a CT scan with contrast to check the blood flow in my head. I experienced a quick onset of a headache that lasted about 20 minutes 4 weeks ago. I have been having some pressure headaches since then, but I also have a sinus infection.   However, sometimes I have a sharp pain that only lasts a matter of seconds or minutes. The pain is in different places of my head. Pain is not to severe and advil helps when needed.  In addition, I have tingling sensations in my head. I had an MRI w/o contrast 1 1/2 years ago due to tingling/numbness in my hands and feet.  The MRI came back clear.....still have the tingling and don't know why.  

History.....I am a 48 year old woman with ventricular tachycardia and am on Bystolic to lower my heart rate (blood pressure has always been  good), have asthma and take singulair, asmanex, and ventolin.  I am concerned with the contrast because of side effects.....one being that it can cause a rapid heart beat which would not be good for me.  Also, my mother has kidney disease.  I've talked to my doctor, but she states I need to make the decision.  My insurance denied the approval, which I was told my doctor will have to speak to the doctor for the insurance company to possibly get approved.  This has all made  me second guess the decision to have the CT scan with contrast.

My question......based on the information I've given you, am I at high risk of having a blood flow problem or aneursym? Should I have the CT scan with contrast?

Thanks for the advice.

[Abhijeet Ghosh]

Dear Friend,
Many thanks for the post.
All i know that, if there is a 0.1 percent chance of aneurysm, then we should not wait for the scan.
Regarding the contract, the nephrologist will be able to guide us better , as whether it's safe or not.
Hence i will not comment, let the nephrologist guide us.
We need to wait till that.

Please discuss, as what do you feel.
Will guide you from there.
Regards