Contrast-enhanced MRI of intrasellar arachnoid cysts: relationship between the pituitary gland and cyst

We recently encountered two large intrasellar arachnoid cysts extending to the suprasellar region. The intensity of the cyst contents was identical to that of the cerebrospinal fluid on both T1- and T2-weighted MRI. On contrast-enhanced MRI, the pituitary gland was compressed posteroinferiorly and flattened in the sella turcica. In this report of rare intrasellar arachnoid cysts the discussion is focused on dislocation of the pituitary gland.     

Long-term MR follow-up of cerebral lesions in neuro-Behçet's disease

To study the long-term evolution of cerebral lesions in neuro-Behçet's disease, MRI was carried out on 12 patients, with follow-up from 1.5 to 6 years (mean 3.5 years). On the first MRI, 66 lesions in all were found; each patient had 1–10 lesions (mean 5.5). There were 30 (46 %) lesions in the brain stem, 18 (27 %) in the basal ganglia region and 18 (27 %) in the periventricular white matter. Of these 22 (33 %) were small, 31 (47 %) medium-size and 13 (20 %) large lesions. On the last MRI, 60 lesions were found; each patient had 1–10 lesions (mean 5). At this time 31 lesions (52 %) were in the brain stem, 13 (22 %) in the basal ganglia region and 16 (26 %) in the periventricular white matter. There were 41 (68 %) small, 13 (22 %) medium-size and 6 (10 %) large lesions. About 40 % of the lesions disappeared, 35 % reduced in size and 25 % remained unchanged. No lesion had enlarged. Of the 60 final lesions 20 (34 %) were not observed on the first study. Small new lesions were found in 5 of 12 patients (42 %), and were asymptomatic. Medium-size or large new lesions were found in 2 patients (17 %) who had stopped steroid treatment and had a neurological relapse. Enlargement of the ventricular system or worsening of initial cerebral atrophy was observed in 9 of 12 patients. Appearance of small lesions and worsening of cerebral atrophy on long-term follow-up suggest the possibility of subclinical progression of cerebral vasculitis and should be considered in the prognosis of neuro-Behçet's disease.     

Deep cerebral invasion by basal cell carcinoma of the scalp

We report recurrent basal cell carcinoma of the scalp with deep cerebral invasion in an 82-year-old man. Plain films and CT showed extensive, full thickness, skull destruction at the vertex. Gadolinium-enhanced MRI revealed neoplastic invasion of the meninges and left cerebral hemisphere, down to the lateral ventricle. We postulate that tumour extended into the brain along perivascular spaces of transcerebral vessels. This hypothesis is supported by the cleft-like contrast enhancement on MRI.     

Vascular patterns in reactive and malignant lymphadenopathy

A total of 130 superficial lymph nodes were evaluated using color Doppler flow imaging (CDFI) in order to differentiate benign from malignant lympadenopathy. The patterns of intranodal flow signals detected at standardized conditions by CDFI were classified using eight self-defined criteria and were correlated with the histopathological or clinical diagnosis. Nonparametric discriminant analysis showed that four vascular patterns were suspicious of malignancy: (a) avascular areas, (b) displacement of intranodal vessels, (c) accessory peripheral vessels and (d) aberrant course of central vessels. Of the neoplastic lymph nodes (n = 73), 96 % showed at least one pathological vascular pattern. Malignancy could be excluded in 95 % of 57 reactive lymph nodes using these four criteria. Most reactive lymph nodes in contrast demonstrated a vascular hilus and/or vessels running at the long axis of the lymph node with branches to the cortex. There was a diagnostic accuracy of 41–82 % in the additionally evaluated sonomorphological (size, shape, echogenicity) and Doppler (increased Pourcelot's or pulsatility indices) criteria. The definitive interpretation of the promising results of this retrospective study requires confirmation of examiner independency as well as prospective evaluation. Correspondence to: A. Tschammler     

Reye's syndrome with cortical laminar necrosis: MRI

Serial MRI findings are described in two patients with Reye's syndrome, demonstrating diffuse cortical and white matter changes. In the acute stage, T2-weighted images showed subtle but definite laminar high signal and contrast-enhanced T1-weighted images laminar enhancement, along the entire cerebral cortexbilateraly. In the chronic stage, unenhanced T1-weighted images showed diffuse cortical laminar high signal. These characteristic MRI features seemed very similar to those of laminar cortical necrosis in hypoxic brain damage. MRI also displayed delayed white matter changes with cerebral atrophy.     

Regional myocardial motion and thickening assessed at rest by ECG-gated99mTc-MIBI emission tomography and by magnetic resonance imaging

We have validated ECG-gated emission tomography using technetium-99m methoxyisobutylisonitrile for the assessment of regional ventricular function by comparing it with cine magnetic resonance imaging (MRI). Gated tomography was performed at rest in 24 patients referred for myocardial perfusion imaging [17 males and seven females with a mean age of 58 years, nine of whom had had a previous myocardial infarction (MI)]. Scores were assigned to each of nine myocardial segments for wall motion and for thickening. Cine MRI was analysed in an identical fashion. Four out of 216 (2%) segments were uninterpretable by gated tomography because of inadequate tracer uptake. In eight patients without coronary artery disease (CAD), wall motion and thickening were normal by both methods. Gated tomography showed abnormal wall motion or thickening in all patients with previous MI and in five of seven patients with CAD but no prior MI. Association between wall motion and thickening was good (r _s=0.86). Overall, there was good agreement between gated tomography and MRI for both wall motion (178/212 segments, =0.66) and wall thickening (184/212 segments, =0.69). In segments with severely reduced perfusion, however, there was poorer agreement (=0.31). Interobserver and intraobserver agreement was high ( from 0.61 to 0.78). Thus, in patients investigated for CAD, there is good overall agreement between gated tomography and MRI but the agreement is lower in segments with severe perfusion defects.     

Indium-111 octreotide scintigraphy in patients with bone tumours of the extremities

Radiolabelled somatostatin analogues are of potential value in the imaging of somatostatin receptor-positive tumours. Recently, somatostatin receptors have been demonstrated in the osteoblast precursor cells. In this preliminary study, we evaluated the uptake characteristics of indium-111 octreotide in two benign and two malignant bone tumours. Tracer accumulation was observed in all four cases, and overall lesion to background ratio (mean±SD) was 2.74±0.84 and 2.98±1.49 at 4 h and 24 h, respectively. There was no clear relationship between I¹¹¹In-octreotide accumulation and the benign or malignant nature of the tumour. In one patient, tracer uptake was inhibited by unlabelled octreotide administration. These results suggest that¹¹¹In-octreotide can be taken up by benign and malignant bone tumours. The inhibition of tumour uptake by treatment with cold octreotide supports the concept that specific uptake mechanisms are responsible for¹¹¹In-octreotide deposition by bone tumours.     

An unusual cervical chordoma: CT and MRI

We report CT and MRI findings of an unusual cervical chordoma. CT showed only minimal bony destruction with a lobulated prevertebral mass. Sagittal MRI, however, clearly demonstrated a lesion involving the body of C2 extending prevertebrally and into the spinal canal.     

Ultra-high-speed MR imaging

Conventional magnetic resonance imaging (MRI) has been shown to provide excellent morphological images of the body organs, particularly structures undergoing little physiologic motion. Nevertheless, the clinical usefulness of MRI has been hampered by long acquisition times, high cost of scanning because of limited patient throughput, and image artifacts due to patient motion. With recent technical developments, several ultrafast scanning techniques capable of acquiring images in a breath-hold now find their introduction into clinical use. The system improvements are potentially useful for a vast range of applications hitherto not accessible to MR imaging. Among these are functional brain imaging, realtime imaging of cardiac motion and perfusion, fast abdominal imaging, improved MR angiography, and potentially real-time monitoring of interventional procedures. Whereas some ultrafast techniques can be performed on conventional scanners, echo-planar imaging, the fastest currently available data acquisition strategy, requires specially designed hardware. This article provides on overview of the technical advances in the ultrafast MRI and discusses potential applications and the possible future impact on body scanning.Correspondence to: G. K. von Schulthess     

MRI of the inner ear: use of modified GRASS and fast spin-echo sequences

We report our experience with MRI of the normal and pathological inner ear with fast spin-echo and modified gradient recalled at steady state sequences. Although earlier studies on temporal bone MRI were discouraging, improvements in MR technology combined with the use of paramagnetic contrast media can make MRI a useful diagnostic tool for the assessment of inner ear pathology. Conventional spin-echo imaging seems not to be the modality of choice because of the relatively thick slices and the long acquisition times. Received: 9 March 1994 Accepted: 27 January 1995