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DOI: 10.1055/s-0042-1759485
Hypodense Sign in Lungs on CT in Immunocompromised Patient
We read with interest the article entitled “Imaging Approach to Pulmonary Infections in the Immunocompromised Patient” by Grover et al.[1] We would like to add a “hypodense sign” (HyS) to the list of radiological findings described by the authors. The HyS was described by Horger et al as[2] the presence of a central area of hypodensity seen on narrow window settings (width: 110–140 Hounsfield Units [HU]; level: 15–40 HU). This sign can be seen in consolidation or nodule and can be appreciated on unenhanced scans, computed tomography pulmonary angiography (CTPA), and contrast-enhanced scans. This sign has been reported to be associated with invasive pulmonary aspergillosis, mucormycosis, and fusariosis.[3] [4] The hypodense nodule sign has been described in the context of immunocompromised patients. The underlying pathogenesis is infarction secondary to angioinvasion by fungal elements.[3] [4] This sign may be a precursor for forming a cavity.[2] [5] Some studies have described the importance of hypodense sign in diagnosing invasive mold disease ([Table 1]). Hence, it is a helpful sign in arriving at the diagnosis of invasive mold disease with a sensitivity of 23% on high-resolution CT (HRCT) and 64% on CTPA, and a specificity of 100% on HRCT and 98% on CTPA.[3] This sign can help to differentiate between bacterial and fungal diseases in immunocompromised individuals.[2] [3] This sign has also been described in some bacterial infections, particularly in tuberculosis, i.e., a cavity filled with central mucous within or in case of a pulmonary abscess; however, leukocytes play a vital role in abscess formation, and immunocompromised individuals usually have neutropenia.[3] [6] Hence, we would like to add the hypodense sign as a useful diagnostic sign in CTs of immunocompromised individuals.
Study |
Sample size |
Type of scan |
Patient population |
---|---|---|---|
Horger et al[2] |
43 |
Unenhanced scan |
Neutropenic patients |
Sassi et al[3] |
127 |
HRCT and contrast-enhanced CT |
Hematological Malignancies |
Qin et al[5] |
25 |
CT chest with intravenous contrast and without intravenous contrast |
Liver transplant patients |
Stanzani et al[6] |
44 |
Unenhanced scan and CTPA |
Hematological malignancies |
Schulze et al[7] |
17 |
Noncontrast CT and volume perfusion CT |
Hematological malignancies |
#
Conflict of Interest
None declared.
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References
- 1 Grover SB, Grover H, Antil N, Patra S, Sen MK, Nair D. Imaging approach to pulmonary infections in the immunocompromised patient. Indian J Radiol Imaging 2022; 32 (01) 81-112
- 2 Horger M, Einsele H, Schumacher U. et al. Invasive pulmonary aspergillosis: frequency and meaning of the “hypodense sign” on unenhanced CT. Br J Radiol 2005; 78 (932) 697-703
- 3 Sassi C, Stanzani M, Lewis RE. et al. The utility of contrast-enhanced hypodense sign for the diagnosis of pulmonary invasive mould disease in patients with haematological malignancies. Br J Radiol 2018; 91 (1083): 20170220
- 4 Alexander BD, Lamoth F, Heussel CP. et al. Guidance on imaging for invasive pulmonary aspergillosis and mucormycosis: from the imaging working group for the revision and update of the Consensus Definitions of Fungal Disease from the EORTC/MSGERC. Clin Infect Dis 2021; 72 (Suppl 2): S79-S88
- 5 Qin J, Meng X, Fang Y. et al. Computed tomography and clinical features of invasive pulmonary aspergillosis in liver transplant recipients. J Thorac Imaging 2012; 27 (02) 107-112
- 6 Stanzani M, Sassi C, Lewis RE. et al. High resolution computed tomography angiography improves the radiographic diagnosis of invasive mold disease in patients with hematological malignancies. Clin Infect Dis 2015; 60 (11) 1603-1610
- 7 Schulze M, Vogel W, Spira D, Sauter A, Hetzel J, Horger M. Reduced perfusion in pulmonary infiltrates of high-risk hematologic patients is a possible discriminator of pulmonary angioinvasive mycosis: a pilot volume perfusion computed tomography (VPCT) study. Acad Radiol 2012; 19 (07) 842-850
Address for correspondence
Publication History
Article published online:
20 December 2022
© 2022. Indian Radiological Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)
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References
- 1 Grover SB, Grover H, Antil N, Patra S, Sen MK, Nair D. Imaging approach to pulmonary infections in the immunocompromised patient. Indian J Radiol Imaging 2022; 32 (01) 81-112
- 2 Horger M, Einsele H, Schumacher U. et al. Invasive pulmonary aspergillosis: frequency and meaning of the “hypodense sign” on unenhanced CT. Br J Radiol 2005; 78 (932) 697-703
- 3 Sassi C, Stanzani M, Lewis RE. et al. The utility of contrast-enhanced hypodense sign for the diagnosis of pulmonary invasive mould disease in patients with haematological malignancies. Br J Radiol 2018; 91 (1083): 20170220
- 4 Alexander BD, Lamoth F, Heussel CP. et al. Guidance on imaging for invasive pulmonary aspergillosis and mucormycosis: from the imaging working group for the revision and update of the Consensus Definitions of Fungal Disease from the EORTC/MSGERC. Clin Infect Dis 2021; 72 (Suppl 2): S79-S88
- 5 Qin J, Meng X, Fang Y. et al. Computed tomography and clinical features of invasive pulmonary aspergillosis in liver transplant recipients. J Thorac Imaging 2012; 27 (02) 107-112
- 6 Stanzani M, Sassi C, Lewis RE. et al. High resolution computed tomography angiography improves the radiographic diagnosis of invasive mold disease in patients with hematological malignancies. Clin Infect Dis 2015; 60 (11) 1603-1610
- 7 Schulze M, Vogel W, Spira D, Sauter A, Hetzel J, Horger M. Reduced perfusion in pulmonary infiltrates of high-risk hematologic patients is a possible discriminator of pulmonary angioinvasive mycosis: a pilot volume perfusion computed tomography (VPCT) study. Acad Radiol 2012; 19 (07) 842-850