Thoracic Imaging 2003 - Society of Thoracic Radiology
Thoracic Imaging 2003 - Society of Thoracic Radiology
Thoracic Imaging 2003 - Society of Thoracic Radiology
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MONDAY<br />
118<br />
AJRCCM Prospective CTA Validation, 2002<br />
Fortunately, there are some well-constructed and logical<br />
studies that confirm the clinical role <strong>of</strong> CTA- even single slice<br />
CTA- and document the accuracy <strong>of</strong> a negative CTA during follow-up<br />
intervals. Lorut et al. reported results in a prospective<br />
(n=247) cohort <strong>of</strong> patients suspected <strong>of</strong> PE and studied with<br />
CTA, V/Q, and d-dimer levels all within 24 hours [18]. Gold<br />
standars for diagnosis included:<br />
Positive PE: CTA positive or DVT US positive (US was performed<br />
only if the if CTA was negative or inconclusive and the<br />
VQ was nondiagnostic)<br />
Negative PE: CTA negative and one <strong>of</strong> other stated criteria met<br />
The prevalence PE in the cohort was 42%; CT diagnosed<br />
73% <strong>of</strong> these cases; US 23%; VQ 4% (VQ diagnoses were only<br />
in patients who did not undergo CT, US diagnosed DVT, not<br />
PE). The mortality rates in patients with (treated) and without<br />
(not treated) PE were comparable; recurrent PE /DVT rate was<br />
1-2% in each group. The authors conclude that CTA positive<br />
diagnoses are reliable, negative CTA results were never overturned<br />
unless by leg ultrasound showing DVT, and that the VQ<br />
is superfluous.<br />
Outcomes After Negative CTA: European Journal <strong>of</strong><br />
<strong>Radiology</strong>, 2001<br />
Several outcomes studies are also now available documenting<br />
negligible PE or DVT rates in patients 3-6 months after negative<br />
CTA. Gottsater et al. reported 3-month outcomes in 305<br />
patients studied with CTA for possible PE; 61 (20%) had a CTA<br />
diagnosis <strong>of</strong> PE, and 215 <strong>of</strong> the negative CTA group were followed<br />
and not treated. Three (1.4%) <strong>of</strong> these patients developed<br />
DVT or PE; 2 had underlying advanced malignancy and one had<br />
COPD [19]. The authors conclude that patient outcomes after<br />
negative CTA are no different than outcomes reported after normal<br />
VQ or conventional angiography.<br />
Outcomes After Negative CTA in High risk Patients, 2001<br />
Ost et al. studied 103 patients who had intermediate or low<br />
probability VQ scans and a high clinical suspicion for PE with<br />
CTA: 22 were positive, 71 negative, and 10 indeterminate. Only<br />
3 <strong>of</strong> the 71 patients with negative CTA had a PE in a 6 month<br />
follow-up period [20]. Thus, even in these symptomatic patients<br />
with non-normal scintigraphy, negative CTA appears to be safe.<br />
This has been our clinical experience as well.<br />
CONCLUSIONS<br />
• CTA has all the desired attributes <strong>of</strong> a test for PE/DVT<br />
• Multi-channel CTA is an angiogram- but better<br />
• The accuracy, particularly <strong>of</strong> multi-channel CTA, exceeds<br />
100% for PE<br />
• Multi-channel CTA is the best test for subsegmental (and<br />
smaller) clot<br />
• CTA allows rapid estimate <strong>of</strong> clot age and extent<br />
• CTA facilitates other diagnoses in the chest and allows leg<br />
vein assessment<br />
• Perfusion analysis and color volumetric images possible in<br />
the near future<br />
• Not all CTA is the same: beware simplistic accuracy quotes<br />
and meta-analyses<br />
• Be suspect <strong>of</strong> the literature: especially if no radiologist is involved<br />
• New research directions: redo all aspects <strong>of</strong> PE from physiology<br />
to treatment<br />
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