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Invasive mold disease (IMD) is an important cause of morbidity and mortality in immunocompromised patients. The finding of a “halo sign” (an area of ground-glass attenuation surrounding a nodule) on high-resolution computed tomography (HRCT) has been considered suggestive of this infection but not diagnostic. However, angioinvasion — a characteristic of IMD — can be detected by computed tomographic pulmonary angiography (CTPA) as blood-vessel interruption at the border of a focal lesion.
In a recent single-center study, researchers in Italy explored the diagnostic usefulness of CTPA in 36 immunocompromised patients with clinically suspected IMD and positive HRCT findings. Among these patients, 5 (14%) had proven, 7 (19%) had probable, and 24 (67%) had possible IMD at final diagnosis, based on European Organization for Research and Treatment of Cancer/Mycosis Study Group criteria.
CTPA showed an interruption of the arterial vessels, consistent with angioinvasive fungal disease, in all 5 patients with proven IMD (100%), as well as in 5 of 7 with probable IMD (71%) and 9 of 24 with possible IMD (37.5%). Among the 16 patients with positive CTPA findings, 12 had a halo sign on HRCT and 4 did not (P=0.001).
Stanzani M et al. Computed tomographic pulmonary angiography for diagnosis of invasive mold diseases in patients with hematological malignancies. Clin Infect Dis 2012 Mar 1; 54:610.
Herbrecht R and Roedlich M-N. Earlier diagnosis of angioinvasive pulmonary mold disease: Is computed tomography pulmonary angiography a new step? Clin Infect Dis 2012 Mar 1; 54:617.
Comment
These data suggest that CTPA, available in most medical centers, may be a useful tool for diagnosing IMD in high-risk patients with suspicious but nonspecific findings on HRCT. Editorialists and the authors note potential complications of the procedure, including acute kidney injury and other adverse events related to use of contrast media, as well as increased exposure to radiation.