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Biomedical subjects

A R Wright

Publications and source records attributed to A R Wright.

8 recordsLinked to original sources

Fat-suppression magnetic resonance imaging in the preoperative localization of parathyroid adenomas.

Prospective localization of parathyroid adenomas was attempted in 16 patients with hyperparathyroidism prior to surgery. All patients had magnetic resonance imaging (MRI) using T1-weighted spin-echo (SE) sequences and a fat-suppression sequence, the short-tau inversion recovery (STIR) sequence. Correlation with the results of surgery yielded an overall sensitivity of 71% and a specificity of 94%. Performance was good in patients with previous surgery and with ectopic tumours. We believe that fat-suppression MRI is a valuable technique in the preoperative localization of parathyroid adenomas in patients with hyperparathyroidism.

Adenoma

MR pelvimetry--a practical alternative.

Pelvimetry remains a useful technique as part of the assessment of the term breech pregnancy where vaginal delivery is planned. MR pelvimetry is accurate, well tolerated and shows soft-tissue structures as well as bone. It avoids the potentially carcinogenic effects of ionising radiation and is thought to be completely safe for mother and fetus. A technique of MR pelvimetry is described which uses gradient-echo sequences. This quick, practical method makes minimal inroads into valuable scanning time, and may therefore be considered a potentially cost-effective alternative to conventional pelvimetry.

Adolescent

Effects of exercise on left ventricular diastolic performance in trained athletes.

Dynamically trained athletes develop increased left ventricular (LV) wall mass. To determine whether this increased wall mass impaired characteristics of LV diastolic filling, serial Doppler echocardiograms were obtained from 10 trained athletes (mean age 21 years) at rest, during supine graded bicycle exercise and during recovery at heart rates of 80, 120 and 140 beats/min, respectively. Similar studies were obtained in 10 age-matched control subjects. Studies at rest showed significant increases in athletes in LV end-diastolic dimension and indexed LV wall mass. Differences in peak filling rates and in normalized peak lengthening rates between athletes and control subjects were seen at heart rates of 140 beats/min during exercise and recovery. Differences in Doppler-derived variables between athletes and control subjects were seen in total time-velocity integral, early peak filling velocity and E/A ratio. In athletes, time-velocity integral was increased during recovery at heart rates of 120 beats/min and 80 beats/min, early peak filling velocity was increased during exercise at 120 beats/min and during recovery at 120 beats/min and 80 beats/min, and E/A ratio was higher at all heart rates during both exercise and recovery. Although no significant differences were found in LV diastolic filling indexes at rest, a significant enhancement was found in these parameters in dynamically trained athletes during exercise, particularly at higher levels of dynamic exercise.

Adult

A comparative study of left ventricular structure and function in elite athletes.

Adaptations to left ventricular (LV) structure and function appear to be dependent on the type, intensity and duration of exercise training. We therefore studied two clearly defined groups of elite athletes, by M-mode and Doppler echocardiography, with a group of inactive individuals as controls. All groups were age matched. Group 1 comprised ten elite endurance athletes with maximal oxygen consumption (VO2 max) of 74.7 +/- 1.43 (mean +/- SEM). Group 2 consisted of ten elite weightlifters with VO2 max 45.3 +/- 2.00. Group 3 comprised of ten inactive individuals with VO2 max 44.5 +/- 2.13. Left ventricular end diastolic dimension was significantly higher in group 1 (5.72 +/- 0.07) than in groups 2 or 3 (5.29 +/- 0.09 and 5.19 +/- 0.09 respectively, p less than 0.001). Left ventricular mass index was significantly higher in groups 1 and 2 (156.4 +/- 5.97 and 138.6 +/- 7.27 respectively) than in group 3 (104.1 +/- 3.16 p less than 0.001). Percentage fractional shortening was used as an index of systolic function and no significant difference was found between groups. Doppler E:A ratio was taken as an index of diastolic function and was found to be significantly elevated in group 1 at rest (3.37 +/- 0.24) compared with 2.38 +/- 0.16 and 1.99 +/- 0.10 in groups 2 and 3 respectively (p less than 0.003). On exercise, the E:A ratio in group 1 was significantly higher than in group 3 (1.95 +/- 0.14 and 1.23 +/- 0.05 respectively p less than 0.001), and tended to be higher than group 2 (1.68 +/- 0.15 p = ns). These data show that both modes of intense training produce left ventricular hypertrophy. Diastolic function is not impaired in the athletes and may be augmented in the endurance athletes.

Adolescent

Computed tomography in the preoperative assessment of Poland's syndrome.

Four cases of Poland's syndrome were investigated with thoracic computed tomography (CT) to determine the precise extent of the upper limb girdle abnormalities. CT confirmed in all cases the absence of the sternocostal head of pectoralis major and clearly showed associated abnormalities of pectoralis minor, serratus anterior and latissimus dorsi as well as bony structures. In view of the importance of latissimus dorsi in reconstructive surgery, we believe that a limited thoracic CT scan provides useful information in patients with Poland's syndrome requesting anterior axillary reconstruction and breast mound formation.

Adolescent

MR and CT in the assessment of Poland syndrome.

Seven cases of Poland syndrome were investigated with CT and/or MR to assess the extent of the muscle abnormalities of the shoulder girdle. In all cases the absence of the sternocostal head of the pectoralis major was clearly shown, as were any associated abnormalities of the pectoralis minor, serratus anterior, and latissimus dorsi. The latissimus dorsi muscle has an important role in reconstructive surgery and can be difficult to assess clinically. Cross-sectional imaging with CT or MR will give useful information in patients with Poland syndrome requesting anterior axillary reconstruction and breast mound formation.

Adolescent