No abstract

Primary bone lymphoma is an uncommon malignancy that accounts for less than 5% of all primary bone tumors. The radiographic appearances of primary bone lymphoma are variable, and, because the lesion can appear near normal on plain radiographs, a second modality such as bone scintigraphy or magnetic resonance (MR) imaging should be used. Despite this variability, the presence of a solitary, permeative, metadiaphyseal lesion with a layered periosteal reaction on plain radiographs and a soft-tissue mass on MR images, especially in a patient older than 30 years, is highly suggestive of lymphoma. The case for a diagnosis of primary bone lymphoma is further strengthened if the soft-tissue mass and marrow changes are associated with surprisingly little cortical destruction. Primary bone lymphoma has a better prognosis than many other malignant bone tumors; therefore, early identification allows for appropriate treatment. MR imaging not only permits early identification but also depicts the extent of soft-tissue involvement and can be used to assess the outcome of treatment.

Meningiomas are the most common dural tumour. They are regularly being seen as an incidental finding on brain imaging and treated conservatively. However, there are many other dural masses which mimic their appearances, including primary neoplastic processes, metastases, granulomatous diseases and infection. While some of these are rare, others such as metastases and tuberculosis arise relatively frequently in practice. Although not pathognomonic, key features which increase the probability of a lesion being a meningioma include intralesional calcifications, skull hyperostosis, local dural enhancement and increased perfusion. It is important to have an awareness of these entities as well as their main imaging findings, as they have a wide range of prognoses and differing management strategies. This review outlines several of the most important mimics along with their imaging findings on both standard and advanced techniques with key features which may be used to help differentiate them from meningiomas.

Cerebral microbleeds have emerged as an important new imaging marker of cerebral small vessel disease. With the development of MRI techniques that are exquisitely sensitive to paramagnetic blood products, such as T2*-weighted gradient-recalled echo and susceptibility-weighted sequences, microbleeds have been detected in ever-increasing numbers of patients in stroke and cognitive clinics, as well as in healthy older people and in a variety of other rarer diseases and syndromes. Detection of cerebral microbleeds has clinical implications with respect to the diagnosis of the underlying small vessel disease, the safety of antithrombotic use, and the risk of symptomatic intracerebral haemorrhage, cognitive impairment and dementia. This article provides a guide to the detection and clinical relevance of cerebral microbleeds in different conditions based on a comprehensive review of the literature and own findings in research and clinical practice.

A relatively small (approximately 100 kDa) Gd(3+)-based contrast agent, which gives positive contrast on MR images, can be used to detect tumor cell death in vivo, and future derivatives of it may be used to assess early tumor responses to treatment.