Predictors of mortality in alpha1-antitrypsin deficiency

BACKGROUND

Lung density measurements by computed tomography have previously been found to be a more sensitive indicator of disease progression in emphysema of alpha(1)-antitrypsin deficiency than lung function measurements. The aim of this study was to investigate the predictive potential of several parameters, including CT scanning, for mortality in patients with severe alpha(1)-antitrypsin deficiency.

METHODS

Over a 5 year period, 256 patients with alpha(1)-antitrypsin deficiency (PiZ phenotype) were assessed, of whom 254 underwent lung function testing and 197 had thoracic CT scans. Lung function, CT scans, health status (St George's Respiratory Questionnaire, SGRQ), and other clinical data of survivors and non-survivors were compared and these parameters were applied to survival analyses.

RESULTS

There were 22 deaths in this patient cohort, 10 of which were classified as "respiratory" deaths. Baseline lung function parameters (forced expiratory volume in 1 second (FEV(1)), carbon monoxide transfer coefficient (KCO)), and CT scores were significantly lower in the non-survivors than in the survivors. 170 of the 256 patients had complete data for entry into multiple regression analyses (Cox proportional hazards model). In the univariate analysis, upper zone expiratory scan had the best association with all cause (p = 0.001) and respiratory mortality (p<0.001), whereas FEV(1) (p = 0.158 all cause, 0.015 respiratory) and KCO (p = 0.002 all cause, 0.012 respiratory) had poorer associations with mortality. Only age gave further independent predictive information regarding all cause or respiratory mortality when the CT scan was entered into the survival analyses.

CONCLUSIONS

CT scanning predicts respiratory and all cause mortality in alpha(1)-antitrypsin deficiency and appears to be superior to lung function parameters, especially FEV(1).

Developmental abnormalities of the great vessels of the thorax and their embryological basis

Congenital abnormalities of the thoracic vascular system are commonly encountered in radiological practice. A pictorial review of these abnormalities using a variety of imaging modalities is presented and their embryological basis described. A knowledge of their embryological derivation helps the understanding of these abnormalities.

Longitudinal changes in physiological, radiological, and health status measurements in alpha(1)-antitrypsin deficiency and factors associated with decline

The FEV(1) declines rapidly in alpha(1)-antitrypsin deficiency (alpha(1)-ATD) but less is known about other measures of disease severity and the factors, other than smoking, that are associated with progression of emphysema. The natural history of alpha(1)-ATD was studied prospectively in 43 patients with the PiZ phenotype and emphysema at a single center over 2 yr. The mean +/- SE change in FEV(1) was -67 +/- 14 ml/yr, accompanied by a reduction in transfer factor (mean change in diffusing capacity of the lung for CO [DL(CO)] -1.07 +/- 0.21 ml/min/mm Hg/yr; p < 0.001) and lung density in the upper zones as assessed by quantitative high-resolution computed tomography (HRCT) (mean change in voxel index 2.8 +/- 0.6%/yr; p < 0.001). The decline in FEV(1) related to baseline FEV(1) (r = -0.56, p < 0.001), bronchodilator reversibility (r = 0.52, p < 0.001), and (for patients with FEV(1) > 35% predicted) exacerbation frequency (r = -0.38, p = 0.02). There was also a decline in the St. George's Respiratory Questionnaire (SGRQ) Activity score (mean change -4.3 +/- 1.2 units/yr, p < 0.001) that correlated with FEV(1) decline (r = 0.45, p = 0.002). Progression of emphysema in alpha(1)-ATD is dependent on baseline physiology and exacerbation frequency and may be detected by several different measurements of which HRCT density mask analysis and DL(CO) appear most sensitive.

High-resolution computed tomography scanning in alpha1-antitrypsin deficiency: relationship to lung function and health status

The development of computed tomography (CT) has enabled emphysema to be assessed noninvasively. Objective quantification of lung density correlates well with lung function in patients with chronic obstructive pulmonary disease and has been shown to be a sensitive tool for monitoring disease progression. In order to determine the clinical impact of changes seen on high-resolution computed tomography (HRCT), the relationship between the objective quantification of emphysema on HRCT, lung function and health status in 111 patients with alpha1-antitrypsin deficiency was examined (PiZ). The degree of HRCT scan abnormality correlated well (p<0.001 for all comparisons) with forced expiratory volume in one second (r = -0.60- -0.75), specific airway conductance (r = -0.67-0.76), residual volume/total lung capacity (r = 0.46-0.58) and transfer factor of the lung for carbon monoxide (r = -0.64- -0.81). In addition, the CT scans correlated (p<0.001) with health status as assessed by the St. George's Respiratory Questionnaire (SGRQ total: r = -0.38-0.50) and the Short-Form health survey (e.g. physical functioning: r = -0.39-0.54). In summary, other workers have shown high-resolution computed tomography to be a sensitive indicator of disease progression. This study confirms the relationship between high-resolution computed tomography and lung physiology, and suggests the relationship is even stronger in patients with predominantly lower zone pan-lobular emphysema than in usual chronic obstructive pulmonary disease. High-resolution computed tomography also relates to patients disability and impairment as defined by health status questionnaires and, therefore, should be considered as an alternative outcome measure particularly in alpha1-antitrypsin deficiency.

Exercise capacity predicts health status in alpha(1)-antitrypsin deficiency

Resting lung function is only weakly related to health status in chronic obstructive pulmonary disease, reflecting the multifactorial causes of impairment and the heterogeneous nature of the condition. The current study examined whether density mask analysis of high-resolution computed tomography (HRCT) or exercise capacity were better surrogates for health status in a well-defined, homogeneous group of patients with alpha(1)-antitrypsin deficiency (PiZ). Twenty-nine patients with predominantly lower zone emphysema on HRCT were studied. Exercise was assessed by incremental treadmill (V O(2) peak) and shuttle walking tests (ISWT) and health status by the St. George's Respiratory Questionnaire (SGRQ) and SF-36. Although lower zone expiratory HRCT was related to exercise capacity (rho = -0.64 and -0.63 for V O(2) peak and ISWT, respectively, p < 0.001), multiple regression analysis suggested that FEV(1) was a marginally better predictor (rho = -0.64 and -0.65, p < 0.001). HRCT also related significantly to health status (rho = -0.37 for SGRQ activity, p < 0.05), although again FEV(1) showed a stronger relationship (rho = -0.43, p = 0.01). However, exercise capacity was the best predictor of health status with the ISWT accounting for up to 55% of the variability seen in SGRQ total and up to 53% of the SF-36 domain scores (physical functioning). Although both HRCT and lung function relate to health status, exercise capacity is the best predictor of patients disability in these patients with predominantly lower zone emphysema.

Photoactivity tests of TiO2-based inorganic sunscreens. Part 1: Non-aqueous dispersions

A new method of measuring photoactivity of a major group of inorganic sunscreens (coated titanium dioxide) is presented based on the photobleaching of the radical 1,1-diphenyl-2-picrylhydrazyl.

Physiological and radiological characterisation of patients diagnosed with chronic obstructive pulmonary disease in primary care

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is common although often poorly characterised, particularly in primary care. However, application of guidelines to the management of such patients needs a clear understanding of the phenotype. In particular, the British guidelines for the management of COPD recommend that the diagnosis is based on appropriate symptoms and evidence of airflow obstruction as determined by a forced expiratory volume in one second (FEV(1)) of <80% of the predicted value and an FEV(1)/VC ratio of <70%.

METHODS

A study was undertaken of 110 patients aged 40-80 years who had presented to their general practitioner with an acute exacerbation of COPD. The episode was treated at home and, when patients had recovered to the stable state (two months later), they were characterised by full lung function tests and a high resolution computed tomographic (HRCT) scan of the chest.

RESULTS

There was a wide range of impairment of FEV(1) which was in the normal range (>/=80%) in 30%, mildly impaired (60-79%) in 18%, moderately impaired (40-59%) in 33%, and severely impaired (<40%) in 19% of patients. A reduced FEV(1)/VC ratio was present in all patients with an FEV(1) of <80% predicted but also in 41% of those with an FEV(1) of >/=80% predicted. Only 5% of patients had a substantial bronchodilator response suggesting a diagnosis of asthma. Emphysema was present in 51% of patients and confined to the upper lobes in most (73% of these patients). HRCT evidence of bronchiectasis was noted in 29% of patients and was predominantly tubular; most (81%) were current or ex-smokers. A solitary pulmonary nodule was seen on 9% of scans and unsuspected lung malignancy was diagnosed in two patients.

CONCLUSIONS

This study confirms that COPD in primary care is a heterogeneous condition. Some patients do not fulfil the proposed diagnostic criteria with FEV(1) of >/=80% predicted but they may nevertheless have airflow obstruction. Bronchiectasis is common in this group of patients, as is unsuspected malignancy. These findings should be considered when developing recommendations for the investigation and management of COPD in the community.

Prediction of thoracic aortic aneurysm expansion: validation of formulae describing growth

BACKGROUND

The expansion rate of thoracic aortic aneurysms may be an important and clinically relevant index of the risk of rupture. The aims of this study were to assess the validity of three published exponential equations that predict expansion rate in a separate sample population, and to calculate an expansion rate formula for this cohort of patients.

METHODS

We studied 88 consecutive patients undergoing serial computed tomographic or magnetic resonance imaging scanning to monitor thoracic aortic aneurysm progression. In interval scans of at least 6 months, we measured minimum coronal aortic diameter at seven set levels and maximal diameter, yielding 780 segment-intervals.

RESULTS

The linear expansion rate (mean 2.6 mm/year) increased with incremental aortic diameter (aortic diameter < 40 mm: 2.0; 40-49 mm: 2.3; 50-59 mm: 3.6; > or = 60 mm: 5.6 mm/year; p < 0.01). Regression analysis showed close correlation between predicted and sample data, but there were significant differences between observed and expected measurements. The Yale formula underestimated growth by 0.8 mm, while Mt. Sinai and Osaka formulae overestimated actual change by 1.5 and 0.2 mm, respectively. The expansion rate derived from our population was: last diameter = initial diameter x e(0.00367 x time) (r = 0.617).

CONCLUSIONS

Although formulae derived from one thoracic aortic aneurysm sample population may not extrapolate exactly to others, there is close concordance of results for patient populations in three different continents.

Multiplanar reformatting and three-dimensional reconstruction: for pre-operative assessment of the thoracic aorta by computed tomography

INTRODUCTION

Conventional CT demonstrates pathology of the thoracic aorta. This study aimed to evaluate the additional contributions to surgical planning of multiplanar reformatting, maximum intensity projections and three-dimensional (3-D) reconstruction.

DESIGN

Retrospective. SUBJECT AND METHODOLOGY: Fifty-three patients with newly diagnosed pathology of the thoracic aorta were scanned over a 15-month period; 25 scans were spiral acquisitions. Scans were acquired during and following rapid injection of 100 ml of intravenous iopromide. The reconstructed data was displayed as axial images, oblique or other multiplanar reformats and shaded surface display 3-D reconstructions. Two radiologists and two surgeons reviewed the images. The axial images were assessed initially, subsequently the reformats and 3-D reconstructed views were examined looking particularly for additional information that might add to the surgical management.

RESULTS

Pathologies encountered were aortic dissection (21 patients, including two with Marfan's syndrome), saccular aneurysms (eight), fusiform aneurysms (16), aortic root and ascending aortic dilatation (seven) and coarctation (one). The relationship of aneurysms and dissections to major vessels are better shown with 3-D reconstruction or oblique reformats. Morphology of saccular aneurysms, particularly the neck, is well shown with 3-D reconstruction. Coarctation was best demonstrated by oblique reformats. There was little additional information from 3-D reconstruction or reformats in assessment of type A dissection. Improved spatial orientation by visualization in varying projections was helpful for surgical planning in certain cases of type B dissection, fusiform aneurysms and aortic root and ascending aortic root dilatation. Spiral acquisitions have the advantage of speed and hence a greater anatomical coverage for a single breath-hold.

CONCLUSION

Oblique reformats and 3-D reconstruction, although using identical data as the axial images, in specific cases were felt to aid surgical assessment of aneurysms and dissections, thus assisting pre-operative planning.

Spontaneous pneumothorax associated with expectoration of a lump of metastatic renal cancer

The case report of a patient known to have metastatic renal cancer and right main bronchus obstruction is presented. During an episode of haemoptysis, the patient expectorated a large fragment of tissue, which proved to be metastatic renal cell cancer. This event produced a right-sided hydropneumothorax with partial re-expansion of the previously collapsed right lung. A chest tube was inserted producing a full re-expansion, following which pleurodesis with tetracycline was performed. To our knowledge, this is the first ever description of spontaneous clearance of a malignant bronchial obstruction.

The impact of insecticides on beneficial arthropods in cotton agro-ecosystems in South Africa

The unique diversity of beneficial arthropods in South Africa can be regarded as an important natural resource in agro-ecosystems as it plays an important role in the natural control of insect pests. Insecticide applications reduce the ability of these beneficials to regulate cotton pests. In the absence of insecticides, average daily predation rates of 37% and 30% of bollworm eggs and larvae respectively were found in exclusion experiments. By minimizing the number of pesticide applications the combination of the direct negative effect of pesticide application on predator populations and secondary pesticide effects such as the stimulation of red spider mite populations as a result of predator suppression, can be avoided. This would open the option to fully utilize the full pest control potential of the natural enemy complex.

High resolution computed tomography (HRCT) in emphysema associated with alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin (AAT) deficiency is an inherited disorder associated with an increased prevalence of pulmonary emphysema. To date there has been no description of the appearances on CT of the emphysema associated with AAT deficiency. We have reviewed the CT scans of 17 patients with proven AAT deficiency. Eleven out of 17 were examined with HRCT. The CT features were correlated with those on chest radiography. Areas of low density corresponding to parenchymal destruction and reduced perfusion, and attenuation of the pulmonary vasculature were present in all cases. Frank bulla formation occurred in 7/17 patients and was not a major feature. A striking CT finding was bronchial wall thickening and/or dilatation in 7/17 patients with gross cystic bronchiectasis in one patient. In contrast to appearances on chest radiography the upper zones were affected in all cases (17/17) and fine section scanning was particularly valuable in demonstrating changes in these less severely affected regions. Estimation of the extent of disease correlated well with abnormal lung function tests.

Haemorrhagic cerebral metastases from malignant testicular teratoma

Cerebral metastases from malignant testicular teratoma may show complex appearances with magnetic resonance imaging (MRI), which are consistent with changes resulting from repeated haemorrhage. Haemorrhage causes enlargement and symptomatic progression of cerebral lesions, and this can occur even when extracranial disease or other cerebral lesions remain static.

Peritoneal mesothelioma: the role of computed tomography in diagnosis and follow up

Computed tomography (CT) was performed on 15 patients with proven peritoneal mesothelioma. Eight of these patients underwent follow-up CT. It was found that a discrete and measurable mass is unusual in comparison with the common occurrence of ascites and that therefore CT has little role in quantifying the disease. Ascites is usually a prominent feature. Other features (e.g. omental infiltration) were evaluated and these could be used to assess disease progression.

Theory and practice: how much contrast for myelography?

A questionnaire sent to members of the British Society of Neuroradiologists revealed that the majority of practitioners will, when necessary, inject more than 3 g of iodine during myelography with iohexol or iopamidol. The 3 g limit recommended by the contrast medium manufacturers is not based upon scientific studies involving these media, and it is the experience of British neuroradiologists that larger amounts of modern contrast agents can be used without an increase in post myelography complications. There is, therefore, a need for a controlled trial to assess the question of the most appropriate dose of contrast medium in myelography.

Pulmonary Mycobacterium kansasii infection successfully treated with a regimen containing erythromycin

We report a case in which erythromycin was used in place of rifampicin after a severe reaction to the latter in the treatment of pulmonary Mycobacterium kansasii infection.