What is the role of MRI in the diagnosis of pulmonary Kaposi sarcoma (KS)?

Updated: Mar 13, 2019
  • Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR; Chief Editor: Eugene C Lin, MD  more...
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Answer

There is little evidence that MRI is as useful as other methods in diagnosing pulmonary KS. Although MRI is an excellent modality for detection of thoracic wall involvement, it is not useful in intrathoracic lesions apart from, perhaps, imaging large-vessel involvement.

In a study by Khalil et al of a series of 10 patients with AIDS-related KS, T1-weighted spin-echo images showed focally increased signal intensity in the pulmonary parenchyma. [15] Enhancement was observed in parenchymal lesions and along the bronchovascular bundles after the intravenous administration of a gadolinium-based contrast agent. The second echo of T2-weighted spin-echo images resulted in markedly reduced signal intensity in affected areas. The findings were not observed in a control group of patients with AIDS-related Pneumocystis jiroveci pneumonia (PCP). The signal intensity of KS lesions has been postulated to be related to the angiomatous and fibrous components of the tumor.

Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see Medscape and Nephrogenic Systemic Fibrosis.


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