The influence of MR field strength on the detection of focal liver lesions with superparamagnetic iron oxide.

The purpose of this study was to compare the value of low- vs high-field MR systems in the detection of focal liver lesions after IV administration of iron oxide particles. A prospective study was undertaken which included 20 patients with focal liver lesions on CT or US, or strong clinical suspicion of focal liver disease. Iron oxide particles were administered in an IV drip infusion over 30 min. Magnetic resonance imaging was subsequently performed on a 0.2 and a 1.5-T system. Both examinations were performed in one session. Turbo spin-echo T2-weighted sequences were used for further analysis (at 0.2 T: TR 4050 ms, TE 96 ms; 1.5 T: TR 3000 ms, TE 103 ms). After randomisation, images were analysed by two blinded readers. The evaluation included lesion counts, determination of lesion conspicuity and overall image quality (both graded on a scale 1-5). Quantitative analysis was performed on 29 lesions. Lesion-to-liver signal intensity and contrast-to-noise ratios (CNRs) were calculated. The total lesion count (cumulative counts for two observers) was 59 on the high-field system and 63 on the low-field system. Statistical analysis showed no significant difference. On both systems median value for lesion conspicuity was 3. No statistically significant difference was found. Global image quality was rated higher on the high-field system: 3 vs 2 for the low-field system (p = 0.0017). Quantitative analysis showed no significant difference for lesion-to-liver signal intensity ratios or CNRs. Although subjective image quality is significantly better on the high-field system, this does not result in better lesion detection or better lesion conspicuity. No significant difference in objective quantitative parameters was found in our series.

Distribution and incidence of degenerative spine changes in patients with a lumbo-sacral transitional vertebra.

The purpose of this prospective study was to determine the overall incidence and distribution of lumbo-sacral degenerative changes (i.e. disc protrusion or extrusion, facet degeneration, disc degeneration, nerve root canal stenosis and spinal stenosis) in patients with and without a lumbo-sacral transitional vertebra (LSTV). The study population consisted of 350 sequential patients with low back pain and/or sciatica, referred for medical imaging. In all cases CT scans of the lumbo-sacral region were obtained. In 53 subjects (15%) and LSTV was found. There was no difference in overall incidence of degenerative spine changes between the two groups. We did find, however, a different distribution pattern of degenerative changes between patients with and those without an LSTV. Disc protrusion and/or extrusion occurred more often at the level suprajacent to the LSTV than at the same level in patients without LSTV (45.3% vs 30.3%). This was also the case for disc degeneration (52.8% vs 28%), facet degeneration (60.4% vs 42.6%) and nerve root canal stenosis (52.8% vs 27.9%). For spinal canal stenosis there was no statistically significant difference between the two categories. In conclusion, our findings indicate that an LSTV does not in itself constitute a risk factor for degenerative spine changes, but when degeneration occurs, it is more likely to be found at the disc level above the LSTV.

Catamenial pneumothorax caused by thoracic endometriosis.

A 28-year-old woman presented with monthly returning thoracic pain and cough. Catamenial pneumothorax was diagnosed. Thoracoscopy showed multiple nodules on the diaphragm, parietal pleura and lung itself, which proved to be thoracic endometriosis. Thoracoscopy is a useful procedure for diagnosis and treatment of this rare condition.