Jane Marie Suh BA, Presenter: Nothing to Disclose

John Joseph Cronan MD, Abstract Co-Author: Nothing to Disclose

Utilizing multi-detector CT, there has been a marked increase in the diagnosis of PE without any change in mortality. Reports of pulmonary embolus occurring in 3-5% of the normal patients suggest we are diagnosing PE previously undetected by VQ scanning or a single-slice CT.

We reviewed the medical records of the last 50 patients diagnosed with pulmonary embolus by 16 or 64 MDCT who also had a lower extremity venous ultrasound. We plotted the location of the clot detected within the PA and noted the actual width and size of the clot. Our cohort comprised 26 F, 24 M, age range 21-90, mean 56.1 years.

In 30 patients, extensive clot was noted in the central pulmonary arteries (divisions 1-3). In 20 of these patients, DVT was also diagnosed. In 20 remaining cases diagnosed as having pulmonary emboli, we found tiny clots in the 4th through 6th generation pulmonary arteries which ranged in size from 1.5-4mm (mean 2.3mm). These clots were almost uniformly noted to have blood flowing around them and except in the most terminal branches were focal, rounded and had a “dot-like” appearance. DVT was detected in only one of these 20 patients. Four of the 50 patients had complications of anticoagulation. Two of these complications, one being death, occurred in patients with “dots” who had no lower extremity DVT on US.

Peripheral focal-filling defects within the PA, which we termed “dots,” are not clots in the traditional sense and might well represent “normal” embolic activity from the lower extremity venous valves. Small peripheral defects within the PA are not associated with detectable clot load in the lower extremities. We suggest that focal “dot-like” filling defects in the peripheral pulmonary artery in the absence of detectable clot in the lower extremities should not trigger a therapeutic regimen for PE. Although further work is needed, we suggest that “dot-like” peripheral filling defects in the PA in the absence of lower extremity DVT should not be treated.

Radiologists need to understand that all pulmonary emboli are not equal. Small peripheral emboli may not require treatment.

Suh, J, Cronan, J, Dots Are Not Clots: The Over-diagnosis and Over-treatment of PE.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6011555.html