U. Blum et al., INVASIVE PULMONARY ASPERGILLOSIS - MRI, CT, AND PLAIN RADIOGRAPHIC FINDINGS AND THEIR CONTRIBUTION FOR EARLY DIAGNOSIS, Chest, 106(4), 1994, pp. 1156-1161
prospective study was conducted in 38 patients with nodular lesions on
plain chest radiographs and the clinical suspicion of invasive pulmon
ary aspergillosis (IPA) to assess the diagnostic accuracy of magnetic
resonance imaging (MRI) and computed tomography (CT). For early diagno
sis of IPA (clinical signs and symptoms <10 days), CT scans with demon
stration of the halo sign had a high sensitivity (16/22) and specifici
ty (8/8). Magnetic resonance imaging performed at the same time reveal
ed a relatively higher sensitivity (22/22), but a very poor specificit
y (0/8). Gadolinium-diethylene-triamine-pentaacetic acid (Gd-DTPA) enh
anced images did not improve specificity. In the later course of infec
tion (clinical signs and symptoms >10 days), MRIs showed typical nodul
ar target-like lesions with Gd-DTPA enhancement of the rim area that w
as not seen in the early course of the disease or in patients with Pse
udomonas or staphylococcal infection. In conclusion, MRI findings are
not as characteristic as the CT halo sign in diagnosing IPA in the ear
ly course of the disease, but the MRI target sign with Gd-DTPA enhance
ment of the rim area and the ''reverse target'' on T-2-weighted images
are strongly suggestive of IPA at a later stage of the disease.