CNS complications of hematopoietic stem cell transplantation.

OBJECTIVE: With the worldwide increase in the use of hematopoietic stem cell transplantation (HSCT), a high level of diligence is required for radiologists to understand HSCT-related complications in the CNS. This article describes the clinical background of HSCT and complications that occur in a time-dependent manner through the course of HSCT and addresses pivotal issues in diagnostic imaging. CONCLUSION: Acknowledging the realm of imaging manifestations and the underlying mechanism of HSCT will enhance diagnostic accuracy and optimize treatment decisions.

A case of hypopituitarism due to inflammatory myofibroblastic tumor of the sella turnica.

An 18-year-old man with 4-year history of central diabetes insipidus and partial pituitary dysfunction was admitted to our hospital because of headache and nasal discharge. Magnetic resonance imaging (MRI) revealed abnormal mass in the sella turnica invading into the cavernous sinus and sinus maxillaries along with thickened tentorium cerebelli. Histopathology of the mass in the sinus maxillaries revealed spindle-shaped cells arranged in a fascicular pattern with varied myxoid and collagenized regions with various inflammatory cells. Immunostaining revealed the spindle-shaped cells were positive for smooth muscle actin. These features were identical to those of inflammatory myofibroblastic tumor (IMT). He was diagnosed with IMT in the sella turnica and other regions. Corticosteroid therapy improved clinical symptoms and follow-up MRI revealed amelioration of the thickened tentorium cerebelli. However, the other lesions were unchanged and pituitary dysfunction did not improve. Although rare, IMT should be considered in the differential diagnosis of a sellar mass. Early treatment with corticosteroid therapy may reduce the risk of disease progression.

MRI tight posterior fossa sign for prenatal diagnosis of Chiari type II malformation.

INTRODUCTION: Chiari type II malformation (CMII) is one of three hindbrain malformations that display hydrocephalus. We have observed that cerebrospinal fluid (CSF) signal in the posterior fossa, which is always apparent on normal fetal MR images, is not visible in a fetus with CMII. We use the term 'tight posterior fossa' for this MR imaging finding, and evaluate the diagnostic value of this finding on fetal MR images. METHODS: Included in the study were 21 fetuses which underwent brain MR imaging at 1.5 T using two-dimensional balanced turbo-field-echo (2-D balanced-TFE) in the axial and sagittal planes. Postnatal diagnoses were CMII (n=5), CNS abnormalities other than CMII (n=8), and no abnormality (n=8). A tight posterior fossa was defined as an absent or slit-like water signal space around the hindbrain in the posterior fossa on both sagittal and axial MR images. RESULTS: All CMII fetuses displayed a tight posterior fossa on MR images. Hydrocephalus was visualized in all CMII fetuses and myelomeningocele in four fetuses, but hindbrain herniation was visualized only in two of five fetuses. The CSF signal surrounding the hindbrain was clearly visible in all the other 16 fetuses, including five with hydrocephalus not associated with CMII, although it was slightly narrower in a fetus with a cloverleaf skull than in the normal fetuses. CONCLUSION: Tight posterior fossa in the presence of hydrocephalus is a useful and characteristic finding of CMII on fetal MRI.

Magnetic resonance imaging for diagnosis of congenital anosmia.

Magnetic Resonance Imaging (MRI) was performed on 9 patients who lacked a sense of smell since birth. Seven of them, including two patients with Kallmann syndrome, exhibited abnormality of the olfactory bulb, olfactory tract, olfactory sulcus, or rectus gyrus, with some variation among patients in type and degree of abnormality. The other two patients exhibited normal olfactory pathway morphology, and for them the possibility of acquired sensorineural anosmia could not be ruled out. MRI is useful for determining whether patients with congenital anosmia have olfactory pathway anomalies. Many patients with congenital anosmia and hypoplasty or aplasty of the olfactory pathway nevertheless had no gonadal or endocrinological disorders.