Mo Leach

Validation of Non-rigid Registration of Contrast-Enhanced MR Mammography Using Finite Element Methods

This paper presents a validation study for non-rigid registration of 3D contrast enhanced magnetic resonance mammography images. We compare the performance of two non-rigid registration algorithms based on single- and multilevel free-form deformations using B-splines and normalized mutual information. To assess the registration performance, we employ a biomechanical deformation simulator of patient motion likely to occur in vivo.

Intravascular B-cell lymphoma.

A 74-yr-old man presented with fatigue, weight loss, fever, night sweats and unsteady gait. Full blood count showed Hb 146 g/dL, white cell count 11.70 9 10/L, neutrophils of 7.87 9 10/L, platelets 100 9 10/L. Serum lactate dehydrogenase (LDH) and ferritin were elevated at 778 U/L (NR <260) and 1775 ng/mL (NR 20-200), respectively. An infective or inflammatory aetiology was suspected but not confirmed. Brain imaging with MRI showed features of small vessel disease, and CSF examination was normal. CT scan of chest, abdomen and pelvis showed no significant lymphadenopathy or hepatosplenomegaly. A bone marrow biopsy was undertaken but the patient showed progressive clinical deterioration and died within 24 h. The marrow aspirate revealed an infiltrate of highly abnormal large pleomorphic lymphoid cells, sometimes seen in clusters. The nuclei were irregularly shaped with flower-like forms with multiple distinct nucleoli and basophilic vacuolated cytoplasm (Fig. 1). Haemophagocytosis was also a feature. The H+E-stained trephine biopsy was remarkable in showing these large cells to be confined to the blood vessels and marrow sinuses (Fig. 2), which are further outlined on the reticulin stain (Fig. 3). Immunocytochemistry showed them to express CD20 (Fig. 4) confirming a diagnosis of intravascular B-cell lymphoma (IVL). Intravascular (or angiotropic) lymphoma is a rare but aggressive subtype of diffuse large B-cell lymphoma with a median age of presentation of 70 yr (1). Clinical presentation is heterogeneous but most patients develop fever, night sweats and weight loss. Lymphadenopathy and hepatosplenomegaly are uncommon so lymphoma may not be considered in the differential, and diagnoses are often made late.