MR imaging of suspected acute spinal instability

Twenty-two patients with suspected acute vertebral instability were imaged within 48 h of injury using a 0.5 Tesla magnet. In all patients plain radiographs, T1 weighted gradient echo (GE) and STIR sequences were performed. Two radiologists blindly evaluated the magnetic resonance imaging (MRI) scans defining injuries with bony or soft tissue disruption of both columns as unstable. Indirect signs of instability such as soft tissue haemorrhage were recorded and correlated where possible with operative findings. Sixteen patients were radiologically unstable on MRI, five more than on plain films alone. Instability was confirmed operatively in 10 patients. The six other patients with unstable injuries were treated conservatively. Two of these patients had evidence of increased deformity before fracture union. The radiologically stable patients were treated as such and at 6-month review showed no evidence of progressive instability. The presence of soft tissue haemorrhage in the interspinous gap was not associated with ligament rupture unless actual discontinuity was demonstrated at that level. We conclude that using MRI acutely, most unstable spinal injuries can be rapidly and accurately evaluated without the need for further imaging.

MRI of idiopathic orbital inflammatory syndrome using fat saturation and Gd-DTPA

Idiopathic orbital inflammatory syndrome encompasses a group of inflammatory conditions for which no systemic or local cause can be found, and is commonly referred to as orbital pseudotumour. On conventional MRI sequences subtle areas of inflammation or enhancing tissue can easily be masked by the high signal intensity of orbital fat and involvement of the fat itself may not be appreciated. We describe the MRI features of three patients with idiopathic orbital inflammation using frequency-selective fat saturation and Gd-DTPA.

Corticosteroid prophylaxis for patients with increased risk of adverse reactions to intravascular contrast agents: a survey of current practice in the UK

There is no definite experimental evidence that prophylactic corticosteroids reduce the frequency or severity of adverse effects from low-osmolar contrast agents in patients at increased risk of reaction. There is no consensus in terms of how prophylaxis should be conducted. We have studied current radiologists' practice in the UK by sending postal questionnaires to 212 radiologists randomly selected from a list of current consultants who are Fellows of the Royal College of Radiologists. One hundred and seventy (80.2%) of the 212 questionnaires were completed. The majority of radiologists routinely use non-ionic low osmolar contrast media for intravenous administration, only 30 (17.6%) routinely using conventional ionic agents and six (3.5%) ionic low osmolar agents. All 170 use low osmolar contrast media for those patients perceived to be at increased risk of adverse reactions. Seventy-six radiologists (44.7%) never use steroid cover. There is no consistent practice amongst the 94 consultants (55.3%) who do use steroid cover. The indications for prophylaxis vary, as do the corticosteroid used and the dose regime employed. The total dose used varied from the equivalent of 7.5 mg to 400 mg of prednisolone, and the duration of prophylaxis varied from a single dose to a 4 day course. One hundred and forty-two radiologists (83.5%) would welcome nationally agreed guidelines for the use of steroid cover. The great variation in the use of steroid cover in the UK reflects the lack of clear evidence of its benefit in combination with low osmolar contrast media.

Hereditary anemias in Hawaii. 1987

The differential diagnosis of microcytic anemias in Hawaii presents special problems because of the hereditary anemias prevalent in its large Asian subpopulations. Both the alpha- and beta-thalassemias are important because of morbidity and mortality. Heterozygous carriers for either type mimic iron deficiency, which may lead to inappropriate work-up or treatment. The thalassemias and hemoglobin (Hb) variants are all benign in heterozygotes, but if a couple are both heterozygous for the same or for incompatible variants, their children have 25% risk of inheriting a serious anemia. These can be prevented by detecting the heterozygotes, and by offering genetic counseling and fetal testing to couples at risk of having severely affected children. Early detection is also possible by the screening of newborns. Fetal diagnosis, or early detection and treatment, can greatly reduce the consequences of these anemias. Screening and prevention will cost far less than the cost of care for affected patients.

Primary structure of the human renin gene

The gene encoding human renin has been isolated on two overlapping clones from a bacteriophage lambda library of human DNA. The entire gene spans about 12,000 bp and contains 10 exons separated by 9 intervening sequences. The gene structure is similar to that of human pepsinogen in terms of overall size, homology in the coding regions, position of introns, and sizes of the exons, suggesting that the two genes are evolutionarily related. However, a novel exon coding for only three amino acids was detected that is not present in the pepsinogen gene and whose amino acids are also not found in mouse renin. Although the nucleotide sequence of the 5'-flanking DNA differs from that of the pepsinogen gene, in both cases this region contains a structure of almost perfect dyad symmetry which immediately precedes the TATA box and may have functional importance. Furthermore, sequences resembling the putative consensus sequence for glucocorticoid regulation of gene expression are located approximately 200 and 300 bp upstream from the gene. The overall structural anatomy suggests that the human renin gene evolved by mechanisms that include a duplication of exon segments, particularly those containing the codons for the catalytically important aspartate residues, together with the insertion of other exon and flanking DNA structures. An analysis of human chromosomal DNA demonstrates that there is only one gene with high homology to human renin.