Legionnaires' disease caused by Legionella longbeachae: Clinical features and outcomes of 107 cases from an endemic area.

BACKGROUND AND OBJECTIVE: Legionella longbeachae is a predominant cause of Legionnaires' disease in some parts of the world, particularly in Australasia. Clinical reports of L. longbeachae infection are limited to case reports or small case series, and culture-confirmed cases. METHODS: We reviewed the clinical characteristics and outcomes of L. longbeachae pneumonia in a large case series from Christchurch, New Zealand during a 4-year period when both PCR and cultures were used as routine diagnostic tools for Legionnaires' disease. Cases of Legionella pneumophila pneumonia were reviewed for comparison. RESULTS: A total of 107 cases of L. longbeachae infection were identified by PCR and/or culture. The median age was 65 years (range 25-90 years), 63% were male, and most became unwell during spring or summer. Presenting clinical features were similar to those reported for community-acquired pneumonia, with headache, myalgia and diarrhoea being common. Elevated C-reactive protein, hyponatraemia and abnormal liver function tests were also common. History of productive cough, involvement of both lungs, and high bacterial load were independently associated with culture of Legionella from lower respiratory samples. One quarter required intensive care unit admission, and 5% died. Among patients given antimicrobial therapy before admission, those given agents without anti-Legionella activity were more likely to be admitted to the intensive care unit. Limited comparisons were made with the 19 L. pneumophila cases over the same time period. CONCLUSION: Characteristics of L. longbeachae pneumonia are broadly similar to those reported for community-acquired pneumonia from a variety of other populations, except for the spring/summer seasonality.

Measuring and managing radiologist workload: application of lean and constraint theories and production planning principles to planning radiology services in a major tertiary hospital.

INTRODUCTION: We describe how techniques traditionally used in the manufacturing industry (lean management, the theory of constraints and production planning) can be applied to planning radiology services to reduce the impact of constraints such as limited radiologist hours, and to subsequently reduce delays in accessing imaging and in report turnaround. METHODS: Targets for imaging and reporting were set aligned with clinical needs. Capacity was quantified for each modality and for radiologists and recorded in activity lists. Demand was quantified and forecasting commenced based on historical referral rates. To try and mitigate the impact of radiologists as a constraint, lean management processes were applied to radiologist workflows. A production planning process was implemented. RESULTS: Outpatient waiting times to access imaging steadily decreased. Report turnaround times improved with the percentage of overnight/on-call reports completed by a 1030 target time increased from approximately 30% to 80 to 90%. The percentage of emergency and inpatient reports completed within one hour increased from approximately 15% to approximately 50% with 80 to 90% available within 4 hours. The number of unreported cases on the radiologist work-list at the end of the working day reduced. The average weekly accuracy for demand forecasts for emergency and inpatient CT, MRI and plain film imaging was 91%, 83% and 92% respectively. For outpatient CT, MRI and plain film imaging the accuracy was 60%, 55% and 77% respectively. Reliable routine weekly and medium to longer term service planning is now possible. CONCLUSIONS: Tools from industry can be successfully applied to diagnostic imaging services to improve performance. They allow an accurate understanding of the demands on a service, capacity, and can reliably predict the impact of changes in demand or capacity on service delivery.

Measuring and managing radiologist workload: a method for quantifying radiologist activities and calculating the full-time equivalents required to operate a service.

INTRODUCTION: Accurate and transparent measurement and monitoring of radiologist workload is highly desirable for management of daily workflow in a radiology department, and for informing decisions on department staffing needs. It offers the potential for benchmarking between departments and assessing future national workforce and training requirements. We describe a technique for quantifying, with minimum subjectivity, all the work carried out by radiologists in a tertiary department. METHODS: Six broad categories of clinical activities contributing to radiologist workload were identified: reporting, procedures, trainee supervision, clinical conferences and teaching, informal case discussions, and administration related to referral forms. Time required for reporting was measured using data from the radiology information system. Other activities were measured by observation and timing by observers, and based on these results and extensive consultation, the time requirements and frequency of each activity was agreed on. An activity list was created to record this information and to calculate the total clinical hours required to meet the demand for radiologist services. RESULTS: Diagnostic reporting accounted for approximately 35% of radiologist clinical time; procedures, 23%; trainee supervision, 15%; conferences and tutorials, 14%; informal case discussions, 10%; and referral-related administration, 3%. The derived data have been proven reliable for workload planning over the past 3 years. CONCLUSIONS: A transparent and robust method of measuring radiologists' workload has been developed, with subjective assessments kept to a minimum. The technique has value for daily workload and longer term planning. It could be adapted for widespread use.

Measuring and managing radiologist workload: measuring radiologist reporting times using data from a Radiology Information System.

INTRODUCTION: Historically, there has been no objective method of measuring the time required for radiologists to produce reports during normal work. We have created a technique for semi-automated measurement of radiologist reporting time, and through it produced a robust set of absolute time requirements and relative value units for consultant reporting of diagnostic examinations in our hospital. METHODS: A large sample of reporting times, recorded automatically by the Radiology Information System (COMRAD, Software Innovations, Christchurch, New Zealand) along with the description of each examination being reported, was placed in a database. Analysis was confined to diagnostic reporting by consultant radiologists. A spreadsheet was produced, listing the total number and the frequency of reporting times of each distinct examination. Outliers with exceptionally long report times (more than 10 min for plain radiography, 30 min for ultrasound, or 60 min for CT or MRI with some exceptions) were culled; this removed 9.5% of the total. Complex CTs requiring separate workstation time were assigned times by consensus. The median time for the remainder of each sample was the assigned absolute reporting time in minutes and seconds. Relative value units were calculated using the reporting time for a single view department chest X-ray of 1 min 38 s including verifying a report made using speech recognition software. RESULTS: A schedule of absolute and relative values, based on over 179 000 reports, forms Table 2 of this paper. CONCLUSIONS: The technique provides a schedule of reporting times with reduced subjective input, which is more robust than existing systems for measuring reporting time.

Lung cancer screening using multi-slice thin-section computed tomography and autofluorescence bronchoscopy.

BACKGROUND: Thoracic computed tomography (CT) for lung cancer screening is sensitive for the detection of early peripheral lung cancer but is not sensitive for detecting central preinvasive and microinvasive cancer. Our hypothesis is that the use of a two-step strategy, using a sputum biomarker, may increase the detection rate of lung cancer by identifying individuals at highest risk. METHODS: We completed a pilot study of 561 volunteer current or former smokers 50 years of age or older, with a smoking history of more than or equal to 30 pack years. All subjects received induced sputum examination and low-dose thoracic CT scan and were offered autofluorescence bronchoscopy. RESULTS: CT detected 2408 pulmonary nodules, 80% of which were less than or equal to 4 mm in diameter. During 2-year follow-up, 95% of these nodules were stable or resolved, with only 4% showing growth at any time. A total of 28 cancers were detected in 22 subjects: 21 by CT scan and seven by autofluorescence bronchoscopy. Overall, 0.9% nodules were malignant, but growth on more than or equal to two CT scans increased the malignancy rate to 75%. The mean diameter of malignant nodules on detection was 12.8 mm (range, 3 to 36.4 mm). However, 18% of malignant nodules were less than or equal to 4 mm in diameter when first seen. CONCLUSIONS: Multi-detector row CT scanners found multiple small nodules in most subjects screened, but most were stable over the 2-year follow-up. Persistent interval growth increases the probability of malignancy from less than 1% to 75%. One quarter of detected cancers were CT occult and only seen with autofluorescence bronchoscopy. Prescreening using a sputum biomarker improved the detection rate of lung cancer from 3 to 5%.

Reduced radiation dose helical chest CT: effect on reader evaluation of structures and lung findings.

PURPOSE: To assess, by using computer simulation, the effect of the use of reduced computed tomographic (CT) tube current on reader evaluation of structures and lung findings on images obtained at clinically indicated chest CT examinations. MATERIALS AND METHODS: The noise level in the raw scan data of 150 clinically indicated conventional tube current (200-320-mA) chest CT examinations was modified to simulate tube current reduction to 100 and to 40 mA. A total of 450 image sets were thus available. Four radiologists blinded to the tube current used assessed the image sets in random order for 14 structures and lung findings and ranked subjective image quality by using a five-point scale (1 = nondiagnostic, 2 = inferior, 3 = adequate, 4 = good, 5 = excellent). After a 3-week interval, the 150 conventional tube current image sets were rescored so that intraobserver agreement could be assessed. The McNemar statistic was used to determine whether there were more scoring disagreements between interpretations of the conventional and those of the reduced tube current scans or between the two interpretations of the conventional tube current scans. RESULTS: When overall agreement for 14 structures and lung findings was pooled over four observers, significantly more disagreements (P <.05) were seen when scores were compared between conventional and reduced tube current scans than when scores were compared between repeated interpretations of the conventional tube current scans. There was a significant decrease (P <.05) in the subjective image quality of reduced tube current scans compared with the subjective image quality of conventional tube current scans. CONCLUSION: These data indicate that reduced tube current does affect reader evaluation of structures and lung findings and reduces a reader's subjective assessment of image quality.

Asbestosis and idiopathic pulmonary fibrosis: comparison of thin-section CT features.

PURPOSE: To identify differences, if any, in thin-section computed tomographic (CT) features between asbestosis and idiopathic pulmonary fibrosis (IPF) and to test the findings in a subset of histopathologically proved cases of usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP). MATERIALS AND METHODS: Consecutive patients with a diagnosis of IPF (n = 212) or asbestosis (n = 74) were included. The relationships derived from the initial comparison were tested in a separate group of biopsy-proved UIP (n = 30) and NSIP (n = 23) cases. Two observers independently scored thin-section CT images for extent, distribution, and coarseness of fibrosis; proportion of ground-glass opacification; severity of traction bronchiectasis; and extent of emphysema. RESULTS: After controlling for extent of fibrosis, patients with asbestosis had coarser fibrosis than those with IPF (odds ratio, 1.52; 95% CI: 1.25, 1.84; P <.001). Compared with the biopsy-proved cases, the asbestosis cases involved coarser fibrosis (after controlling for disease extent) than the NSIP cases (odds ratio, 2.48; 95% CI: 1.49, 4.11; P <.001) but fibrosis similar to that in the UIP cases. A basal and subpleural distribution of disease was usual in all subgroups but significantly more prevalent (P, <.01 to.001) with asbestosis than with UIP or NSIP. CONCLUSION: The thin-section CT pattern of asbestosis closely resembles that of biopsy-proved UIP and differs markedly from that of biopsy-proved NSIP.

Computed tomography of acute pulmonary embolism.

Pulmonary embolism (PE) is a common condition in which diagnostic and therapeutic delays contribute to substantial morbidity and mortality. Advances in spiral computed tomography (CT) scanner technology over the past 10 years have been paralleled by progressive improvement in the ability to identify and accurately evaluate the pulmonary arteries for acute PE using CT pulmonary angiography (CTPA). Preliminary studies indicate multi-detector CT (MDCT) scanners offer improved accuracy for distal segmental and subsegmental PE. The ability to directly visualize emboli using CTPA has led to its widespread implementation. Published studies using optimal techniques have found sensitivity and specificity of approximately 90%. Clinical signs and symptoms are nonspecific. Only 20% to 30% of those patients evaluated for acute PE are found to harbor emboli. Previous imaging algorithms offered limited diagnostic value for the remaining 70% to 80% of patients who proved not to have PE. It has been shown that spiral CT identifies an alternate diagnosis in approximately 70% of these patients, which, along with its rapid and widespread availability, largely accounts for its popularity with referring clinicians. It is noted that meta-analysis studies of the existing data regarding spiral CT in acute PE have shown deficiencies in study designs, indicating that further research is required. However, at this time, spiral CT is being widely employed in the diagnostic work-up of patients with suspected acute PE. This review will discuss the use of spiral CT for acute PE, including scan acquisition parameters, radiation dose, diagnostic findings, interpretive pitfalls and the role of leg vein studies.

Staging of non-small cell lung cancer: imaging of intrathoracic disease.

This article reviews the contribution of diagnostic imaging to the intrathoracic staging of non-small cell lung cancer. The principle features of the current staging system are discussed along with the relative roles of the various imaging modalities in the evaluation of the primary tumour and metastatic disease. The emerging role of positron emission tomography with fluorodeoxyglucose (FDG-PET) as a clinically useful, potentially cost effective, complementary imaging technique is also reviewed.

The use of visual search for knowledge gathering in image decision support.

This paper presents a new method of knowledge gathering for decision support in image understanding based on information extracted from the dynamics of saccadic eye movements. The framework involves the construction of a generic image feature extraction library, from which the feature extractors that are most relevant to the visual assessment by domain experts are determined automatically through factor analysis. The dynamics of the visual search are analyzed by using the Markov model for providing training information to novices on how and where to look for image features. The validity of the framework has been evaluated in a clinical scenario whereby the pulmonary vascular distribution on Computed Tomography images was assessed by experienced radiologists as a potential indicator of heart failure. The performance of the system has been demonstrated by training four novices to follow the visual assessment behavior of two experienced observers. In all cases, the accuracy of the students improved from near random decision making (33%) to accuracies ranging from 50% to 68%.