I agree with Dr. Teo. CT scan is more informative than scintigraphy. Two weeks after the event  CT is justified also in cases where the diagnosis is not clear enough. For example if a peripheral lung carcinoma comes into consideration for the differential diagnosis. At that time there will be image dynamics in case of PE treated with anticoagulants.

Thank you both for your informed opinions. The event did not take place in the UK rather in another well equiped Western European country. It was the inconsistancy with UK guidelines and protocols which confused me and drew my attention to this particular case.

Actually, there is very little data on resolution rates of PE. The only studies I know are from the late 60's.( Tow DE, Wagner HN. Recovery of Pulmonary Arterial Blood Flow in Patients with Pulmonary Embolism. New England Journal of Medicine. 1967;276(19):1053-9. PubMed PMID: 6025661.; . Dalen JE, Banas JS, Jr., Brooks HL, Evans GL, Paraskos JA, Dexter L. Resolution rate of acute pulmonary embolism in man. N Engl J Med. 1969 May 29;280(22):1194-9. PubMed PMID: 5767460.

However, in a patient of this age ( I assume over 50) it is very unlikely that he will have resolved all his PE, so a "delayed" V/Q is likely; of be of value.

As for the CTPA /V/Q issue, there is now considerable evidence that CTPA over-diagnoses clinically significant PE.

The patient is a 55 year old female with a 2 year history of idiopathic swelling of left calf ( not completely resolved) subsequent to an accidental traumatic soft tissue  injury to right calf muscle, resulting in bilateral Lower limb oedema. DVT excluded in right leg when unilateral swelling was present and in both legs ca. 8 months prior to acute event.

If resolution rates of PE are not adequately evidenced, in your opinion would it make sense to anticoagulate the patient based on clinical presentation, lab values and new ECG findings if perfusion scintigraphy did not reveal evidence of a PE?

Thanks for the references, it will make interesting reading material.

At her age, it is unlikely that she will have resolved a PE in two weeks, so if it is normal then she probably didn't have a PE.

If she has segmental defects, she has probably had a PE at some time in the past, and it's probably worth anticoagulating her for say 3months and see if any resolution occurs.

If there is resolution, then she has had a recent PE. If nothing changes, then you don't know if you're dealing with recent or old PE (which may never resolve completely)..

D-dimer is only helpful if it's normal - there are many causes of a raised d-dimer.

There's a useful review of many issues at:

 Bajc M, Neilly JB, Miniati M, Schuemichen C, Meignan M, Jonson B. EANM guidelines for ventilation/perfusion scintigraphy : Part 2. Algorithms and clinical considerations for diagnosis of pulmonary emboli with V/P(SPECT) and MDCT. Eur J Nucl Med Mol Imaging. 2009 Sep;36(9):1528-38. PubMed PMID: 19629478.

I have to disagree with the opinion that resolution of PE does not occur in two weeks based on literature practice some 50 years ago. We should not forget the efficacy of modern anticoagulants and fibrinolytics.

Actually there is a more recent meta-analysis which shows non-resolution of 50% of patients:

 Nijkeuter M, Hovens MM, Davidson BL, Huisman MV. Resolution of thromboemboli in patients with acute pulmonary embolism: a systematic review. Chest. 2006 Jan;129(1):192-7. PubMed PMID: 16424432.

To quote from their summary : "This review shows that complete resolution of PE is not routinely achieved between 8 days and 11 months after diagnosis. More than 50% of patients with PE still have defects 6 months after diagnosis, after which resolution of thrombi appears to reach a plateau phase. Physicians should be aware of the high percentage of incomplete resolution of pulmonary emboli. Routine re-imaging after

cessation of anticoagulant therapy in patients with PE to obtain a new baseline could be considered."

Thank you Dr. Hilson for this reference. I think 50% resolution is more realistic than no resolution at all. I believe we have reached a good opinion compromise.

Thank you Edward for summining this up so nicely, and thank you to everyone for you contribution.

my research work is in women who ha

Hopefully, I have understood my dear colleague's question properly,but in any case offer the following. I believe that one should perform a scan that may be diagnostic for embolization of the chronic type and the information given should be supplemented with additional clinical history directed toward chronic embolization. However, the information provided is sufficient for the initiation of pulmonary scintigraphy with the caveat that its significance is different than it would be in the acute setting. In specific, a negative scan would not rule out an historic embolic event, but, it would rule out massive chronic inter-current embolization. On the other hand, a positive scan could rule in chronic persistent embolization or a persistent unresolved embolism, and any abnormality detected on such a scan that is not characteristic or definitive for embolism would merit better anticoagulant therapy with repeat scanning after as little as three days or possibly one or two weeks. In that latter case, if the abnormality or abnormalities seen on scanning resolve(s) or is in any way improved one has presumptive evidence of ongoing resolution of prior embolization meriting long term anticoagulation, and a workup for potential etiology.

I have arrived at this opinion following many scans in the chronic setting for patients who are sometimes undiagnosed for months, some of whom arrive for scanning with severe respiratory/circulatory compromise in whom the possibility of embolism has been an afterthought. My belief is that the logistics of these situations preclude refusing to perform a scan that may clinch a difficult diagnosis. Or, to say it another way, no harm is done by performing a scan, provided that we interpret it to be consistent with the patient history.

I agree entirely with Dr.Wesolowski

Given the above history, it seems that the patient needs further investigation to clarify the diagnosis. Anti-coagulation which should not be administered  without a clear diagnosis as it is associated with potential serious complications.

Previous perfusion scintigraphy studies showed that a significant number of patients have residual perfusion abnormality at 3 months after acute PE. Therefore if you do a Q scan few days after the initial episode you are still likely to see the perfusion change.

The problem with Q scan is that it does not differentiate persistent from new perfusion change (chronic vs acute/sub acute PE). CTPA is advantageous although it is not good for residual sub-segmental PE when the proximal PE is resolved. Perhaps best solution is a contrast enhanced CT perfusion!

Thank you Saeed,

The final diagnosis was cardiac decompensation after consultation with a cardio/resp specialist from another hospital; 8 weeks after discharge.

A scintigram was not conducted and the patient received one of the new noac's for 5 weeks prior to the final diagnosis which was then discontinued by the specialist.