Nuclear medicine incident reporting in Australia: control charts and notification rates inform quality improvement.

BACKGROUND: Australia has a statutory incident reporting system for radiopharmaceutical maladministrations, but additional research into registry data is required for the purpose of quality improvement in nuclear medicine. AIMS: We (i) used control charts to identify factors contributing to special cause variation (indicating higher than expected rates) in maladministrations and (ii) evaluated the impact of heterogeneous notification criteria and extent of underreporting among jurisdictions and individual facilities, respectively. METHODS: Anonymised summaries of Australian Radiation Incident Register reports permitted calculation of national monthly maladministration notification rates for 2007-2012 and preparation of control charts. Multivariate logistic regression assessed the association of population, insurance and regulatory characteristics with maladministration notifications in each Australian State and Territory. Maladministration notification rates from two facilities with familiarity of notification processes and commitment to radiation protection were compared with those elsewhere. RESULTS: Special cause variation occurred in only 3 months, but contributed to 21% of all incidents (42 of 197 patients), mainly because of 'clusters' of maladministrations (n = 24) arising from errors in bulk radiopharmaceutical dispensing. Maladministration notification rates varied significantly between jurisdictions (0 to 12.2 maladministrations per 100 000 procedures (P < 0.05)) and individual facilities (31.7 vs 5.8 per 100 000; χ(2) = 40; 1 degree of freedom, P < 0.001). CONCLUSIONS: Unexpected increases in maladministration notifications predominantly relate to incident 'clusters' affecting multiple patients. The bulk preparation of radiopharmaceuticals is a vulnerable process and merits additional safeguards. Maladministration notification rates in Australia are heterogeneous. Adopting uniform maladministration notification criteria among States and Territories and methods to overcome underreporting are warranted.

Low prevalence of significant carotid artery disease on ultrasound in patients proceeding to coronary artery bypass surgery.

BACKGROUND: Cardiothoracic surgery is associated with an increased risk of perioperative stroke. Preoperative carotid ultrasonography can identify significant stenosis, but there is debate about the value of screening. The aims of this study were to (i) determine the prevalence of significant carotid artery disease in screened patients undergoing cardiothoracic surgery and (ii) correlate their ultrasonographic findings with perioperative strokes. METHODS: Retrospective analysis of 166 patients (118 men, 48 women) who underwent a preoperative carotid ultrasound and coronary artery bypass graft surgery (CABG) from 2004 to 2007. Perioperative strokes were recorded and compared with ultrasonographic and clinical data. A separate cohort of 1423 patients (1064 men, 359 women) who underwent CABG over the same period was also evaluated. RESULTS: Only 11 screened patients (6.6%) had significant (>70%) carotid artery disease and two of these underwent simultaneous carotid endarterectomy. There were five perioperative strokes in screened patients, four of which occurred in individuals with <50% disease. Compared with the non-screened cohort, ultrasound screened patients were older and more likely to have a prior stroke or transient ischaemic attack, hypertension, hypercholesterolaemia, peripheral vascular disease and/or renal impairment than non-screened patients. There was no significant difference in perioperative strokes compared with non-screened patients (3% vs 1.2% respectively, P= NS). CONCLUSION: There is a low prevalence of significant carotid artery disease in ultrasound screened patients. The risk of perioperative strokes in screened patients is low and not significantly different from non-screened patients.

Primary sclerosing cholangitis: correlation of hepatobiliary scintigraphy with clinical and laboratory status.

The aim of this study was to determine whether hepatobiliary scintigraphy using (99m)technetium based di-isopropryl-imino-diacetic acid correlated to clinical or laboratory status of patients with primary sclerosing cholangitis (PSC). We carried out a retrospective case-control study involving 15 patients with proven PSC. Fifty-seven hepatobiliary scintigraphic studies were reviewed by consensus of two experienced observers using a semiquantitative scheme to score liver size and degree of radiopharmaceutical uptake, intrahepatic or extrahepatic biliary stasis, segmental liver clearance half-times and gall bladder visualization. The results were compared with age; disease duration; weight loss; serum bilirubin, alkaline phosphatase and albumin levels; antipyrine clearance; number of biliary stents and episodes of cholangitis and history of transplantation. Sixteen age-matched and sex-matched individuals with PSC, who did not undergo hepatobiliary scans, were selected for comparison. Among the scintigraphic variables, right lateral and superior liver clearance half-time values showed a significant linear correlation with disease duration and serum alkaline phosphatase levels (P < 0.05) but not with other clinical or biochemical indices. Other scintigraphic variables showed no correlation. An abnormal, hepatobiliary scan liver clearance half-time in patients with PSC correlates to disease duration and increased serum alkaline phosphatase levels, and this variable may be used to identify some subjects with more advanced disease.

Pneumonia can cause 111indium octreotide uptake.

An 18-year-old woman underwent an (111)In octreotide scan for evaluation of a possible insulinoma. This showed mildly increased radiopharmaceutical uptake involving the right lung base. The patient reported a productive cough for 5 days before the octreotide scan. A chest radiograph was taken, which showed increased airspace opacification in the right lower lobe, corresponding to the uptake seen on the octreotide scan. After a course of oral antibiotics, the patient's chest symptoms improved and the radiograph opacification resolved, confirming the diagnosis of community-acquired pneumonia. This case stresses the need to correlate scan results with the patient's presentation and symptoms to avoid false-positive data.

Improved tolerance to missing data in myocardial perfusion SPET using OSEM reconstruction.

When projection data are incomplete for various technical reasons, artefacts may occur in the reconstructed images. This study examines whether an iterative reconstruction method, the ordered subsets implementation of the EM algorithm (OSEM), can improve reconstruction and minimise the artefacts compared to filtered back-projection (FBP). We varied the number and location of projections removed to investigate when significant artefacts occur, and whether diagnosis is affected. Phantom studies were analysed with sequential orthogonal pairs of projection angles removed (as would typically occur when either data loss or severe motion is detected during acquisition with a right-angled, dual-head cardiac single-photon emission tomography system) and reconstructed with both FBP and OSEM. Twelve normal myocardial perfusion studies were also assessed to study the effect of missing projections on clinical diagnosis. Differences between reconstructions with intact versus missing data were measured. Also, reconstructed images were clinically assessed and scored on a five-point scale based on whether the artefacts would alter clinical interpretation. Although both reconstruction methods showed artefacts, the absolute differences between reconstructed phantom data with intact and missing projection sets were significantly greater (P<0.005) for FBP than for OSEM for all numbers of missing projections. The clinical data showed similar differences between FBP and OSEM reconstructions. The three observers noted superiority of OSEM compared to FBP, with reduced incidence of clinically significant artefacts. However, neither reconstruction method could tolerate six or more missing pairs from 32 projections. There was no significant dependence on the angular location of missing projections. In the absence of any attempt to correct for missing projections, OSEM reduced the influence of artefacts compared to FBP.

Secondary screening for osteoporosis in patients admitted with minimal-trauma fracture to a major teaching hospital.

AIMS: The aim of the present study was to determine: (i) the prevalence of the investigation and treatment of osteoporosis in patients admitted to hospital with a minimal-trauma fracture, (ii) the prevalence of osteoporosis using bone mineral density assessment by dual X-ray absorptiometry (DEXA) in such patients and (iii) a clinical pathway for the management of osteoporosis in such patients. METHODS: A cross-sectional study was undertaken involving all patients admitted with a fracture to Westmead Hospital, Sydney, Australia, between January 1999 and June 2000 (n = 327). Of these, 264 were excluded because of: (i) the fracture following significant trauma (n = 83), (ii) unavailability of medical records for review (n = 38), (iii) nursing home status (n = 37), (iv) previous malignancy (n = 18), (v) deceased (n = 11), (vi) recent osteoporosis screening and/or treatment (n = 18), (vii) refusal to participate (n = 37), (viii) uncontactable (n = 16) and (ix) inadequate English (n = 6). The remaining 63 patients underwent DEXA assessment and the following laboratory investigations: (i) liver function tests, (ii) urea, (iii) electrolytes, (iv) calcium, (v) phosphate, (vi) full blood count, (v) 25-hydroxyvitamin D level and (vi) thyroid-function tests. In men, levels of serum free testosterone, luteinizing hormone, follicle-stimulating hormone and prolactin were also obtained. RESULTS: Of the 63 study participants, 87% of the 47 women were either osteoporotic (T <-2.5) or osteopenic (-2.5

Dual phase 99m-technetium Sestamibi imaging with single photon emission computed tomography in primary hyperparathyroidism: influence on surgery.

The purposes of this study were to determine the positive and negative predictive values of 99m Technetium (99mTc) Sestamibi dual phase imaging with single photon emission computed tomography (SPECT) for parathyroid adenomata or hyperplasia and the effect of preoperative localization on duration of surgery. We reviewed 33 adults (14 men, 19 women; mean age 53 years) with newly diagnosed primary hyperparathyroidism who underwent neck exploration. The duration of surgery for this cohort was compared with a group of historical controls (n = 53) who underwent surgery without preoperative SPECT. At surgery, there were 21 adenomata (including one carcinoma), 10 patients with hyperplasia and two with no pathology detected. The positive predictive values (PPV) for adenomata and hyperplasia were 95% and 100%, respectively. The negative predictive values (NPV) for these entities were 67% and 22%, respectively. The mean weight of adenomata detected was 3.4 g (range 0.2-17 g). Mean duration of surgery was 112.6 min as compared with 113 min in the historical controls (P = not significant). We conclude that 99mTc Sestamibi dual phase imaging with SPECT has an excellent PPV for parathyroid adenomata and hyperplasia, but does not contribute to reduced duration of surgery in patients undergoing neck exploration for the first time. The NPV is low, suggesting that a negative result does not exclude an adenoma or hyperplasia.

Suspected acute pulmonary emboli: cost-effectiveness of chest helical computed tomography versus a standard diagnostic algorithm incorporating ventilation-perfusion scintigraphy.

BACKGROUND: There is a controversy regarding the investigation of patients with suspected acute pulmonary embolism (PE). AIMS: To compare the cost-effectiveness of alternative methods of diagnosing acute PE. Chest helical computed tomography (CT) alone and in combination with venous ultrasound (US) of legs and pulmonary angiography (PA) were compared to a conventional algorithm using ventilation-perfusion (V/Q) scintigraphy supplemented in selected cases by US and PA. METHODS: A decision-analytical model was constructed to model the costs and effects of the three diagnostic strategies in a hypothetical cohort of 1000 patients each. Transition probabilities were based on published data. Life years gained by each strategy were estimated from published mortality rates. Schedule fees were used to estimate costs. RESULTS: The V/Q protocol is both more expensive and more effective than CT alone resulting in 20.1 additional lives saved at a (discounted) cost of $940 per life year gained. An additional 2.5 lives can be saved if CT replaces V/Q scintigraphy in the diagnostic algorithm but at a cost of $23,905 per life year saved. CONCLUSIONS: The more effective diagnostic strategies are also more expensive. In patients with suspected PE, the incremental cost-effectiveness of the V/Q based strategy over CT alone is reasonable in comparison with other health interventions. The cost-effectiveness of the supplemented CT strategy is more questionable.

Mercaptoacetyltriglycine diuretic renography and output efficiency measurement in renal transplant patients.

Suspected urinary tract obstruction following renal transplantation presents a diagnostic dilemma. The purposes of this study were: (1) to establish a normal range of measurement of output efficiency (OE) in the renal transplant population, and (2) to assess prospectively the usefulness of OE in the setting of allograft obstruction. Twenty-two renal transplant patients with stable renal function and no evidence of hydronephrosis on serial ultrasound examination had a diuretic mercaptoacetyltriglycine scan with calculation of OE. Three renal transplant patients with confirmed graft obstruction were also studied. Standard qualitative and quantitative parameters as well as OE were calculated. The mean OE for the 22 normal renal transplant patients was 86.3%+/-3.7% (range: 77%-91%). OE values in the three obstructed patients were 59%, 68% and 75% respectively. It is concluded that OE should normally exceed 77% in renal graft recipients. OE is a promising means of diagnosing functional obstruction in these patients.

Acute renal failure in critically ill patients: evaluation of an ultrasound contrast agent.

The purpose of the present paper was to evaluate an ultrasound contrast agent (Levovist) in patients with oliguric acute renal failure (ARF) in order to assess renal vascularity, differentiate acute tubular from cortical necrosis and predict prognosis. Ten intensive care unit (ICU) patients with oliguric ARF were prospectively investigated by ultrasound including colour, power and pulsed Doppler before and after injection of Levovist. Doppler signals were graded as absent, equivocal or present from the inner and outer portions of the renal parenchyma, and these findings were correlated with clinical parameters and outcome. Only one patient had findings in keeping with acute cortical necrosis. All patients who survived had parenchymal vascularity while only three of six (50%) who died had parenchymal vascularity after Levovist. The ultrasound contrast caused no side effects and additional information was provided which improved diagnostic confidence, enabled appropriate classification of patients as having tubular or cortical necrosis and therefore added prognostic information.

An evaluation of bone mineral density in Australian women of Asian descent.

Asian women have been reported to have lower bone mineral density (BMD) than Caucasians, but this could be due to body habitus rather than ethnicity. The purpose of the present study was to determine whether Australian women of Asian descent have intrinsically dissimilar BMD compared to Australian women of Caucasian origin. We compared Australian Asian (n = 36) and Caucasian (n = 304) women who were referred for bone densitometry and in whom disorders or medications known to interfere with bone metabolism were excluded. Covariables including age, postmenopausal status, years since menopause (YSM), alcohol and smoking consumption, family history, current exercise levels, height, weight, body mass index (BMI) and Asian origin were analysed by multivariate linear regression to determine the independent predictors of BMD in the spine, hip and distal radius. The BMD in the spine (R2 = 0.31), hip (R2 = 0.27) and distal radius (R2 = 0.31) were associated with YSM (all sites), postmenopausal status, weight and smoking (spine and hip), BMI (spine and wrist), family history (hip) and height (wrist). The BMD at these sites were similar for Asian and Caucasian women after adjusting for these variables. Thus, Asian-Australians have similar BMD to Caucasian-Australians after adjusting for potential confounding variables. Bone mineral density is independently related to a number of clinical and lifestyle-related factors, but not ethnicity.

Predicting clinical discordance of bone mineral density.

OBJECTIVE: To identify clinical and lifestyle factors that may predict clinical discordance of bone mineral density (BMD) in otherwise healthy perimenopausal and postmenopausal women referred for bone densitometry. MATERIAL AND METHODS: Data from 304 white women referred for bone densitometry were retrospectively reviewed in order to determine predictors of BMD status at the lumbar spine, femoral neck, and distal radius. In addition, a cross-validation study in a further independent sample of 50 patients was undertaken. Dual-energy x-ray absorptiometry of all three sites was performed, and T-scores were determined with use of standard criteria established by the World Health Organization. Covariables including age, postmenopausal status, years since menopause, use of alcohol and cigarettes, family history of osteoporosis, exercise, height, weight, and body mass index were analyzed by canonical discriminant functions. RESULTS: Seventy-six patients (25%) had normal BMD at all three sites (group A); 55 patients (18%) had osteopenia or osteoporosis at all sites (group B); and 173 patients (57%) showed regional discordance of BMD (group C). Menopausal status, years since menopause, use of alcohol and cigarettes, exercise levels, and weight allowed distinct separation of these three groups by using the plot of one canonical discriminant function against the other. When tested, this method of assignment correctly predicted the regional BMD status in 38 of 50 women (76%) in the independent sample. CONCLUSION: Thus, the combination of certain clinical and lifestyle factors may be helpful in predicting variations in the clinical classification of BMD in an ambulatory healthy perimenopausal or postmenopausal woman.

Sonographic screening for hepatocellular carcinoma in patients with chronic hepatitis or cirrhosis: an evaluation.

OBJECTIVE: The purposes of this study were to determine the incidence of hepatocellular carcinoma (HCC) in patients with chronic hepatitis or cirrhosis and to assess the cost and benefit of sonographic screening for HCC. MATERIALS AND METHODS: We reviewed 647 sonograms of 232 patients obtained over an 8-year period. One hundred fifty-two patients had at least two sonograms. One hundred fifty-four men and 78 women with a mean age of 51 years were included. Most patients (n = 207) had biopsy-proven cirrhosis. Ethnicity, age, gender, type of liver disease, and alpha-fetoprotein levels were analyzed to determine factors associated with HCC detection. The costs of sonography and other tests were calculated using the Australian government Medicare benefits schedule. RESULTS: Thirty-one patients (13%) had elevated alpha-fetoprotein levels. Liver masses were found in 25 (11%) patients. Six (2.6%) patients had HCC on biopsy (n = 3) or other tests. All cases of HCC were inoperable because of tumor multicentricity or metastases (n = 2) or both, or because of the relatively large size or poor physical condition of the patient (n = 4) or both. The only variable associated with detection of HCC was alcohol-related liver disease (p = .01). Of the six patients with HCC, one had an elevated alpha-fetoprotein level. The yearly incidence of HCC was 1.4%. Other masses shown by sonography included regenerating nodules (n = 5), hemangiomas (n = 5), focal fat sparing (n = 4), metastases (n = 2), and other lesions (n = 3). No patient underwent surgical resection, which precluded calculation of a survival benefit. The cost of our screening program was $8472 (United States dollars) per HCC. CONCLUSION. Sonographic screening is superior to alpha-fetoprotein assay for detection of HCC, but in this study, screening did not decrease mortality.

Hysterectomy with ovarian conservation: effect on bone mineral density.

A cross-sectional study was undertaken in 58 consecutive women with premenopausal hysterectomy and ovarian conservation (Group 1) and 59 randomly selected women with natural menopause (Group 2) to determine the effect of hysterectomy on bone mineral density (BMD). Subjects were similar in age, height, weight, body mass index (BMI), exercise levels, family history of osteoporosis and smoking levels, but not years since hysterectomy or menopause (Group 1 = 14.9 +/- 10.8 years versus Group 2 = 9.8 +/- 8.7 years; p = 0.005), age at hysterectomy or menopause (Group 1 = 42.3 +/- 7.3 years versus Group 2 = 45.9 +/- 6.9 years; p = 0.008) or current alcohol consumption (Group 1 = 13.8% versus Group 2 = 39%; p = 0.002). Dual X-ray absorptiometry of the raw (unadjusted) lumbar spine and femoral neck BMD were similar for the 2 groups: lumbar spine = 0.947 +/- 0.179 g/cm2 (Group 1) versus 0.958 +/- 0.203 g/cm2 (Group 2) (p = 0.76) and femoral neck = 0.825 +/- 0.127 g/cm2 (Group 1) versus 0.815 +/- 0.146 g/cm2 (Group 2) (p = 0.71). Multivariate linear regression revealed that factors other than hysterectomy were associated with lumbar spine and femoral neck BMD. Thus, prior hysterectomy with ovarian conservation has no adverse effect on lumbar spine or femoral neck BMD.

Assessment of pediatric hydronephrosis using output efficiency.

UNLABELLED: Diagnosing obstruction in pediatric patients with hydronephrosis, and renal impairment is often difficult. Renal output efficiency (OE) is a parameter that may improve diagnostic accuracy by allowing normalization of washout according to renal function. The aims of this study were to define a normal range for OE in infants and children and to evaluate its diagnostic accuracy in cases with hydronephrosis. METHODS: Seventy-four children (91 hydronephrotic kidneys; median age, 4 mo; 22 girls and 52 boys) underwent 99mTc-labeled mercaptoacetyl-triglycine scintigraphy using intravenous volume expansion (15 ml/kg normal saline), furosemide diuresis and urethral catheterization, if vesicoureteric reflux was present. Images were interpreted by consensus of two or more experienced observers using visual assessment of the images, differential function and clearance half-time after furosemide (T(1/2)), as well as OE. The final diagnosis was based on surgical findings (n = 23 kidneys) or follow-up for >12 mo (n = 68). RESULTS: Final diagnosis in 22 of the 91 hydronephrotic kidneys was obstruction at the pelviureteric (n = 21) or vesicoureteric (n = 1) junction and no obstruction in the remaining 69. The overall diagnostic accuracy of OE was 89%. Using exhaustive search multivariate logistic regression analysis, only reduced OE (p < 0.001) and decreased renal uptake by visual assessment (p = 0.058) were independently predictive of obstruction (R2 = 0.726). In dilated but unobstructed kidneys, mean OE was 93% +/- 7.1%. In the normal kidneys, mean OE was 96% +/- 3.1%. CONCLUSION: OE improves the diagnostic accuracy of diuretic renography in children and neonates with hydronephrosis and suspected obstruction. Output efficiency should exceed 89% in normal kidneys and 79% in unobstructed, hydronephrotic kidneys.

Detection of appendicitis by transvaginal ultrasound: a case report.

Transvaginal ultrasound was performed in a 35-year-old woman with right iliac fossa discomfort in whom initial transabdominal images revealed no abnormality. A thickened hyperemic appendix with appendicolith was identified; subsequent surgery and pathological examination confirmed appendicitis. Transvaginal ultrasound may be valuable in women with suspected appendicitis when standard views are normal or equivocal.

FDG-PET screening for cerebral metastases in patients with suspected malignancy.

2-(18)F-Fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) is increasingly being used in the evaluation of patients with malignancy. Recently, imaging protocols have incorporated ¿whole-body' views acquired over multiple steps. However, with this strategy, brain metastases can potentially go undetected. The aim of this study was to determine whether a supplementary 10-min brain 18F-FDG scan provides additional clinically useful information. Accordingly, we reviewed the studies of 273 patients with various malignancies in whom both whole-body and brain images were performed. Whole-body and regional attenuation-corrected 18F-FDG images were obtained approximately 60 min post-injection. A separate 10-min scan of the brain was subsequently performed. All studies were performed using a standard PET scanner with the images being interpreted by consensus of at least two experienced observers. Altogether, 119 studies were reported as normal (n = 96) or showing anatomic or normal variants (n = 23). Abnormalities involving extracranial organs were identified in 149 (55%) patients. Cerebral metastases were reported in 4 (1.5%) patients, only two of which (0.7%) were unsuspected prior to the PET scan. Incidental pathology (encephalopathy, infarct) was reported but unconfirmed in two further patients (0.7%). We conclude that routine ¿screening' for cerebral metastases in patients with suspected malignancy has a low yield and may not be clinically useful.