Almost all CT scans are now "spiral" CTs.
It refers to a technique where the gantry keeps spinning as the patient moves through the tube (ie the source and the detectors move in a spiral relative to the pt).
High resolution vs low resolution is a separate issue.
I always get a chuckle out of the people requesting a "spiral" CT, as if they're asking for something special. Quit calling it that. Besides, helical is the more common term.
The high resolution CT cracks me up almost as much as the spiral thing. It's like people think "well, if normal resolution is good, then high resolution must be even better." Nope. HRCT and normal chest CTs are reconstructed from the same raw data; it's just that HRCTs are formatted and filtered differently in order to evaluate for interstitial lung disease. Often times, prone imaging is done for HRCT as well. Eighty-five % of the time when someone asks for a HRCT, they just need a regular chest CT.
And yes, for a PE you order a CTPA as soon as you become suspicious.
A CXR rarely helps the diagnosis, so there is no reason to order one first (although it often happens prior to suspicion for PE).
Disagree, although I admit this is common practice. Very few patients, even ones with acute PEs, are so unstable that they can't at least get a portable. Besides, if they're so unstable that you can't get a CXR, then they've got no business in the CT scanner.
Also - as I posted earlier - the CXR isn't to make the diagnosis, but to exclude other problems. That
should be relevant because the presentation of PE is so nonspecific that a lobar pneumonia, pneumothorax, or other explanation for their symptoms found on CXR
should put a halt to the CT.
if you are suspicious for a PE and they are hemodynamically stable. do cxr first, then vq scan if ckd, otherwise go to cta after cxr.
If unstable call intensivist, start lovenox 1mg/kg and get consent for tpa. I don't think imaging is needed as it is a clinical diagnosis if you have the clinical supicion and EKG changes. though they may be having an MI. So get stat troponin and ekg. But even that isn't as helpful because they could be having NSTEMI and troponin elevation is common in right heart strain due to PE also. So would a CTA be appropriate? Start lovenox, rush to scanner, call intensivist. treat with tpa.
PE's are tricky diagnosis.
Relatively new guidelines say that perfusion imaging is now first-line (well, after CXR) in young females with few-to-zero risk factors. It's significantly less dose to the breasts. This only works if you use DTPA for ventilation. If you use xenon, then dose and turn-around time go up, in which case you're better off getting the CT. Of course, nobody pays attention to the guidelines, so everyone gets a CT anyway.