Imaging Findings in Aspergillosis: From Head to Toe

Aspergillosis is a mycotic infection induced by airborne fungi that are ubiquitous. Inhalation of Aspergillus conidia results in transmission through the respiratory tract. The clinical presentation is dependent on organism and host specifics, with immunodeficiency, allergies, and preexisting pulmonary disease constituting the most important risk factors. In recent decades, the incidence of fungal infections has increased dramatically, due in part to the increased number of transplants and the pervasive use of chemotherapy and immunosuppressive drugs. The spectrum of clinical manifestations can range from an asymptomatic or mild infection to a swiftly progressive, life-threatening illness. Additionally, invasive infections can migrate to extrapulmonary sites, causing infections in distant organs. Recognition and familiarity with the various radiological findings in the appropriate clinical context are essential for patient management and the prompt initiation of life-saving treatment. We discuss the radiological characteristics of chronic and invasive pulmonary aspergillosis, as well as some of the typically unexpected extrapulmonary manifestations of disseminated disease.

MR Imaging of Atraumatic Muscle Disorders

Atraumatic disorders of skeletal muscles include congenital variants; inherited myopathies; acquired inflammatory, infectious, or ischemic disorders; neoplastic diseases; and conditions leading to muscle atrophy. These have overlapping appearances at magnetic resonance (MR) imaging and are challenging for the radiologist to differentiate. The authors organize muscle disorders into four MR imaging patterns: (a) abnormal anatomy with normal signal intensity, (b) edema/inflammation, (c) mass, and (d) atrophy, highlighting each of their key clinical and imaging findings. Anatomic muscle variants, while common, do not produce signal intensity alterations and therefore are easily overlooked. Muscle edema is the most common pattern but is nonspecific, with a broad differential diagnosis. Autoimmune, paraneoplastic, and drug-induced myositis tend to be symmetric, whereas infection, radiation-induced injury, and myonecrosis are focal asymmetric processes. Architectural distortion in the setting of muscle edema suggests one of these latter processes. Intramuscular masses include primary neoplasms, metastases, and several benign masslike lesions that simulate malignancy. Some lesions, such as lipomas, low-flow vascular malformations, fibromatoses, and subacute hematomas, are distinctive, but many intramuscular masses ultimately require a biopsy for definitive diagnosis. Atrophy is the irreversible end result of any muscle disease of sufficient severity and is the dominant finding in disorders such as the muscular dystrophies, denervation myopathy, and sarcopenia. This imaging-based classification, in correlation with clinical and laboratory data, will aid the radiologist in interpreting MR imaging findings in patients with atraumatic muscle disorders. ^©RSNA, 2018.

Comparison of MRI and PET-CT in detecting the loco-regional recurrence of soft tissue sarcomas during surveillance

OBJECTIVE

To investigate the diagnostic performance of MRI and PET-CT for the detection of loco-regional recurrences after soft tissue sarcoma (STS) excision.

MATERIALS AND METHODS

From Dec 2003 to Aug 2014, 394 patients with STSs, who were included in the electronic patient registry for initial or repeated surgery at our hospital, were retrospectively reviewed. We identified 152 patients who underwent regular postoperative follow-ups with both MRI and PET-CT, obtained within a 3 month period of each other. We analyzed differences in the performance of MRI and PET-CT for the diagnosis of loco-regional recurrences using McNemar's test. The receiver-operating characteristic curves and calculations of the area under the curve were used.

RESULTS

Twenty patients were found to have a loco-regional recurrence after tumor excision. For MRI and PET-CT, the sensitivities were 90.0 and 95.0 %, and the specificities 97.7 and 95.5 %, respectively, with positive predictive values of 85.7 and 76.0 % and negative predictive values of 98.5 and 99.2 %, respectively. No significant difference was detected between the sensitivities of MRI and PET-CT (p = 0.125). The area under the receiver-operating characteristic curve for PET-CT (0.952) was not significantly greater than that for MRI (0.939; p = 0.6).

CONCLUSION

MRI of the area of interest is recommended for evaluation of tumor recurrence after surgical excision of STS. PET-CT was shown to be effective for detection of STS recurrence, and comparable to MRI. However, if PET-CT or MRI findings are inconclusive, the other modality may be helpful in differentiating tumor recurrence from post-therapeutic tissue change.

Muscle involvement in two Behçet cases: magnetic resonance imaging and histology findings

Behçet's disease (BD) is a systemic vasculitis with a classic trio of symptoms of oral aphthous ulcers, genital ulcers, and ocular lesions that present in a relapsing fashion. Despite these most frequently encountered symptoms of the disease, other systems such as vascular, gastrointestinal, and neurological involvements can also occur. Muscular involvement is rare, and there are only a few cases in the literature, which were reported mainly in a pediatric population. In this two-adult case report, muscular involvement of BD with an emphasis on magnetic resonance imaging and histology findings will be presented.