The impact of contracts on outsourcing computed tomography examinations from a Swedish public university hospital to a private radiology unit.

INTRODUCTION: After years of outsourcing without detailed contracts from one of Sweden's largest university hospitals to external radiology units, the hospital started to use a specific contract for outsourcing computed tomography (CT) examinations. The purpose of this study was to compare the cost-effectiveness of two outsourcing approaches, where examinations were performed either with a detailed, specific contract (with-contract) or without (no-contract), between a hospital radiology department and private external units. METHODS: This retrospective study included a group of electively outsourced CT-examinations (n = 132) and a control group of in-house CT-examinations (n = 132), selected from the three different types of CT-examinations referred from the Departments of Oncology and Hematology. These examinations were randomly selected from four different groups over two time periods of one year each, one being outsourcing without a contract (no-contract, during 2013), one time period with a specific contract (with-contract, during 2014) and two control groups of examinations performed in-house within both these time periods. We compared outsourced examinations (both no-contract and with-contract groups) and in-house examinations. The comparison of these groups include five parameters; management-time, patient waiting-time, the quality of the examinations, - image interpretations and costs. RESULTS: During 2013, management-time for CT-examinations was longer in the outsourced group (no-contract) than in the in-house group, with a statistical significance (P = 0.002). Fewer examinations performed in-house and in the with-contract group needed re-interpretation than in the no-contract group. CT-examinations in the with-contract group were associated with shorter overall management-time, patient waiting time and lower costs compared to the no-contract group. CONCLUSION: Using a contract with detailed specifications for outsourcing CT-examinations may be an effective way of reducing patient waiting time. Outsourcing based on a well-founded contract can be cost-effective, compared with outsourcing without a detailed plan for the services required.

Retention of Gadolinium-Based Contrast Agents in Multiple Sclerosis: Retrospective Analysis of an 18-Year Longitudinal Study.

BACKGROUND AND PURPOSE: Gadolinium-based contrast agents have been associated with lasting high T1-weighted signal intensity in the dentate nucleus and globus pallidus, with histopathologically confirmed gadolinium retention. We aimed to longitudinally investigate the relationship of multiple gadolinium-based contrast agent administrations to the Signal Intensity Index in the dentate nucleus and globus pallidus and any associations with cognitive function in multiple sclerosis. MATERIALS AND METHODS: The Signal Intensity Index in the dentate nucleus and globus pallidus was retrospectively evaluated on T1-weighted MR imaging in an 18-year longitudinal cohort study of 23 patients with MS receiving multiple gadolinium-based contrast agent administrations and 23 healthy age- and sex-matched controls. Participants also underwent comprehensive neuropsychological testing. RESULTS: Patients with MS had a higher Signal Intensity Index in the dentate nucleus (P < .001), but not in the globus pallidus (P = .19), compared with non-gadolinium-based contrast agent-exposed healthy controls by an unpaired t test. Increasing numbers of gadolinium-based contrast agent administrations were associated with an increased Signal Intensity Index in the dentate nucleus (ß = 0.45, P < .001) and globus pallidus (ß = 0.60, P < .001). This association remained stable with corrections for the age, disease duration, and physical disability for both the dentate nucleus (ß = 0.43, P = .001) and globus pallidus (ß = 0.58, P < .001). An increased Signal Intensity Index in the dentate nucleus among patients with MS was associated with lower verbal fluency scores, which remained significant after correction for several aspects of disease severity (ß = -0.40 P = .013). CONCLUSIONS: Our data corroborate previous reports of lasting gadolinium retention in brain tissues. An increased Signal Intensity Index in the dentate nucleus and globus pallidus was associated with lower verbal fluency, which does not prove causality but encourages further studies on cognition and gadolinium-based contrast agent administration.

Incidence of Radiologically Isolated Syndrome: A Population-Based Study.

BACKGROUND AND PURPOSE: Incidental MR imaging findings resembling MS in asymptomatic individuals, fulfilling the Okuda criteria, are termed "radiologically isolated syndrome." Those with radiologically isolated syndrome are at high risk of their condition converting to MS. The epidemiology of radiologically isolated syndrome remains largely unknown, and there are no population-based studies, to our knowledge. Our aim was to study the population-based incidence of radiologically isolated syndrome in a high-incidence region for MS and to evaluate the effect on radiologically isolated syndrome incidence when revising the original radiologically isolated syndrome criteria by using the latest radiologic classification for dissemination in space. MATERIALS AND METHODS: All 2272 brain MR imaging scans in 1907 persons obtained during 2013 in the Swedish county of Västmanland, with a population of 259,000 inhabitants, were blindly evaluated by a senior radiologist and a senior neuroradiologist. The Okuda criteria for radiologically isolated syndrome were applied by using both the Barkhof and Swanton classifications for dissemination in space. Assessments of clinical data were performed by a radiology resident and a senior neurologist. RESULTS: The cumulative incidence of radiologically isolated syndrome was 2 patients (0.1%), equaling an incidence rate of 0.8 cases per 100,000 person-years, in a region with an incidence rate of MS of 10.2 cases per 100,000 person-years. There was no difference in the radiologically isolated syndrome incidence rate when applying a modified version of the Okuda criteria by using the newer Swanton classification for dissemination in space. CONCLUSIONS: Radiologically isolated syndrome is uncommon in a high-incidence region for MS. Adapting the Okuda criteria to use the dissemination in space-Swanton classification may be feasible. Future studies on radiologically isolated syndrome may benefit from a collaborative approach to ensure adequate numbers of participants.

Clinical Feasibility of Synthetic MRI in Multiple Sclerosis: A Diagnostic and Volumetric Validation Study.

BACKGROUND AND PURPOSE: Quantitative MR imaging techniques are gaining interest as methods of reducing acquisition times while additionally providing robust measurements. This study aimed to implement a synthetic MR imaging method on a new scanner type and to compare its diagnostic accuracy and volumetry with conventional MR imaging in patients with MS and controls. MATERIALS AND METHODS: Twenty patients with MS and 20 healthy controls were enrolled after ethics approval and written informed consent. Synthetic MR imaging was implemented on a Siemens 3T scanner. Comparable conventional and synthetic proton-density-, T1-, and T2-weighted, and FLAIR images were acquired. Diagnostic accuracy, lesion detection, and artifacts were assessed by blinded neuroradiologic evaluation, and contrast-to-noise ratios, by manual tracing. Volumetry was performed with synthetic MR imaging, FreeSurfer, FMRIB Software Library, and Statistical Parametric Mapping. Repeatability was quantified by using the coefficient of variance. RESULTS: Synthetic proton-density-, T1-, and T2-weighted images were of sufficient or good quality and were acquired in 7% less time than with conventional MR imaging. Synthetic FLAIR images were degraded by artifacts. Lesion counts and volumes were higher in synthetic MR imaging due to differences in the contrast of dirty-appearing WM but did not affect the radiologic diagnostic classification or lesion topography (P = .50-.77). Synthetic MR imaging provided segmentations with the shortest processing time (16 seconds) and the lowest repeatability error for brain volume (0.14%), intracranial volume (0.12%), brain parenchymal fraction (0.14%), and GM fraction (0.56%). CONCLUSIONS: Synthetic MR imaging can be an alternative to conventional MR imaging for generating diagnostic proton-density-, T1-, and T2-weighted images in patients with MS and controls while additionally delivering fast and robust volumetric measurements suitable for MS studies.

Evaluation of a new system for chest tomosynthesis: aspects of image quality of different protocols determined using an anthropomorphic phantom.

OBJECTIVE: To compare the image quality obtained with the different protocols in a new chest digital tomosynthesis (DTS) system. METHODS: A chest phantom was imaged with chest X-ray equipment with DTS. 10 protocols were used, and for each protocol, nine acquisitions were performed. Four observers visually rated the quality of the reconstructed section images according to pre-defined quality criteria in four different classes. The data were analysed with visual grading characteristics (VGC) analysis, using the vendor-recommended protocol [12-s acquisition time, source-to-image distance (SID) 180 cm] as reference, and the area under the VGC curve (AUCVGC) was determined for each protocol and class of criteria. RESULTS: Protocols with a smaller swing angle resulted in a lower image quality for the classes of criteria "disturbance" and "homogeneity in nodule" but a higher image quality for the class "structure". The class "demarcation" showed little dependency on the swing angle. All protocols but one (6.3 s, SID 130 cm) obtained an AUCVGC significantly <0.5 (indicating lower quality than reference) for at least one class of criteria. CONCLUSION: The study indicates that the DTS protocol with 6.3 s yields image quality similar to that obtained with the vendor-recommended protocol (12 s) but with the clinically important advantage for patients with respiratory impairment of a shorter acquisition time. ADVANCES IN KNOWLEDGE: The study demonstrates that the image quality may be strongly affected by the choice of protocol and that the vendor-recommended protocol may not be optimal.

SWI or T2*: which MRI sequence to use in the detection of cerebral microbleeds? The Karolinska Imaging Dementia Study.

BACKGROUND AND PURPOSE: Cerebral microbleeds are thought to have potentially important clinical implications in dementia and stroke. However, the use of both T2* and SWI MR imaging sequences for microbleed detection has complicated the cross-comparison of study results. We aimed to determine the impact of microbleed sequences on microbleed detection and associated clinical parameters. MATERIALS AND METHODS: Patients from our memory clinic (n = 246; 53% female; mean age, 62) prospectively underwent 3T MR imaging, with conventional thick-section T2*, thick-section SWI, and conventional thin-section SWI. Microbleeds were assessed separately on thick-section SWI, thin-section SWI, and T2* by 3 raters, with varying neuroradiologic experience. Clinical and radiologic parameters from the dementia investigation were analyzed in association with the number of microbleeds in negative binomial regression analyses. RESULTS: Prevalence and number of microbleeds were higher on thick-/thin-section SWI (20/21%) compared with T2*(17%). There was no difference in microbleed prevalence/number between thick- and thin-section SWI. Interrater agreement was excellent for all raters and sequences. Univariate comparisons of clinical parameters between patients with and without microbleeds yielded no difference across sequences. In the regression analysis, only minor differences in clinical associations with the number of microbleeds were noted across sequences. CONCLUSIONS: Due to the increased detection of microbleeds, we recommend SWI as the sequence of choice in microbleed detection. Microbleeds and their association with clinical parameters are robust to the effects of varying MR imaging sequences, suggesting that comparison of results across studies is possible, despite differing microbleed sequences.

Cerebral microbleeds: different prevalence, topography, and risk factors depending on dementia diagnosis­the Karolinska Imaging Dementia Study.

BACKGROUND AND PURPOSE: Cerebral microbleeds are thought to represent cerebral amyloid angiopathy when in lobar regions of the brain and hypertensive arteriopathy when in deep and infratentorial locations. By studying cerebral microbleeds, their topography, and risk factors, we aimed to gain an insight into the vascular and amyloid pathology of dementia diagnoses and increase the understanding of cerebral microbleeds in dementia. MATERIALS AND METHODS: We analyzed 1504 patients (53% women; mean age, 63 ± 10 years; 10 different dementia diagnoses) in this study. All patients underwent MR imaging as part of the dementia investigation, and all their clinical parameters were recorded. RESULTS: Among the 1504 patients with dementia, 22% had cerebral microbleeds. Cerebral microbleed topography was predominantly lobar (P = .01) and occipital (P = .007) in Alzheimer disease. Patients with cerebral microbleeds were significantly older (P < .001), were more frequently male (P < .001), had lower cognitive scores (P = .006), and more often had hypertension (P < .001). Risk factors for cerebral microbleeds varied depending on the dementia diagnosis. Odds ratios for having cerebral microbleeds increased with the number of risk factors (hypertension, hyperlipidemia, diabetes, male sex, and age 65 and older) in the whole patient group and increased differently in the separate dementia diagnoses. CONCLUSIONS: Prevalence, topography, and risk factors of cerebral microbleeds vary depending on the dementia diagnosis and reflect the inherent pathology of different dementia diagnoses. Because cerebral microbleeds are seen as possible predictors of intracerebral hemorrhage, their increasing prevalence with an increasing number of risk factors, as shown in our study, may require taking the number of risk factors into account when deciding on anticoagulant therapy in dementia.

Medial temporal lobe is vulnerable to vascular risk factors in men: a population-based study.

BACKGROUND AND PURPOSE: Vascular risk factors (VRFs) are known to cause cerebral microvascular disease, but evidence supporting an effect of VRFs on regional brain atrophy is mixed. We investigate whether an aggregation of VRFs is associated with volume of hippocampus and entorhinal cortex in elderly people living in the community. METHODS: This cross-sectional study consists of 523 participants (age ≥60 years, 59.3% women) of the SNAC-K Study in central Stockholm, Sweden, who were free of clinical stroke and cognitive impairment. We collected data on VRFs through interviews, clinical examination and inpatient register system. Hippocampal and entorhinal cortex volume was manually measured on magnetic resonance images. Data were analysed with general linear regression models controlling for demographics and total intracranial volume. RESULTS: In men, high total cholesterol and diabetes were significantly or marginally associated with smaller hippocampus and entorhinal cortex; when current smoking, binge alcohol drinking, high cholesterol and diabetes were aggregated, an increasing number of VRFs were significantly associated with decreasing volume of hippocampus and entorhinal cortex (P for linear trend <0.01). In women, none of individual VRFs or their aggregation was significantly associated with the volume of these brain regions, except former smoking that was significantly associated with a larger volume of these regions. CONCLUSIONS: Aggregation of VRFs is associated with reduced hippocampal and entorhinal cortex volume in apparently healthy elderly men, but not in women. This implies that in men, the medial temporal lobe is vulnerable to cardiovascular risk factors.

Quantitative assessment of 99mTc-depreotide uptake in patients with non-small-cell lung cancer: immunohistochemical correlations.

BACKGROUND: Somatostatin receptor (SSTR) scintigraphy with (99m)Tc-depreotide is used for differential diagnosis of solitary pulmonary nodules. The method is based on SSTR expression in cancer tissue. PURPOSE: To estimate the expression of SSTRs in non-small-cell lung cancer (NSCLC) in vitro, and to determine the correlation between (99m)Tc-depreotide uptake in vivo and different tumor characteristics determined in vitro, such as tumor grade, and presence of SSTR2, MIB-1, and p53. MATERIAL AND METHODS: A total of 127 patients with lung lesions detected on computed tomography (CT) were investigated with SSTR scintigraphy after injection of 740 MBq (99m)Tc-depreotide. This study includes 19 patients with NSCLC with histologically proven diagnosis. The quantitative evaluation of (99m)Tc-depreotide was performed using region-of-interest analysis and includes tumor counts/cm(3), background counts/cm(3), and the ratio between tumor and background counts. RESULTS: 99mTc-depreotide uptake was found in all NSCLC tumors, which expressed SSTR2 defined in vitro by immunochemical methods. SSTR2 expression was negatively correlated to the degree of the tumor's differentiation (P<0.05). 99mTc-depreotide uptake in tumor cells did not correlate with tumor grade, or SSTR2, MIB-1, or p53 expression. CONCLUSION: There is an expression of SSTRs in NSCLC. The degree of tumor differentiation correlates negatively with SSTR2 measured in vitro and positively with MIB-1 expression in tumor tissue. No correlation was found between (99m)Tc-depreotide uptake and possible prognostic factors such as MIB-1 and p53 expression in tumor cells in NSCLC. Lastly, no correlation was found between (99m)Tc-depreotide uptake and tumor grade or SSTR2 expression.

One-dimensional-ratio measures of atrophy progression in multiple sclerosis as evaluated by longitudinal magnetic resonance imaging.

BACKGROUND: For decades, normalized one-dimensional (1D) measures have been used in the evaluation of brain atrophy. In multiple sclerosis (MS), the use of normalized linear measures over longitudinal follow-up remains insufficiently documented. PURPOSE: To evaluate the association between different regional atrophy measures and disability in MS patients over four decades in a longitudinal cross-sectional study. MATERIAL AND METHODS: 37 consecutively selected MS patients were included. At baseline, patients had a range of disease duration (1-33 years) and age (24-65 years). Each patient was followed by magnetic resonance imaging (MRI) for a mean of 9.25 years (range 7.3-10 years). Four 1D measures were applied at three time points on axial 5-mm T1-weighted images. Three clinical MS subgroups were represented: relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), and primary progressive MS (PPMS). RESULTS: There were significant changes in all 1D ratios during follow-up. The Evans ratio (ER) and the bifrontal ratio (BFR) were associated with the development of disability. Changes of ER and BFR reflected more aggressive disease progression, as expressed by MS severity score (MSSS). CONCLUSION: All four normalized ratios showed uniform atrophy progression, suggesting a consistent rate of atrophy over long-term disease duration independent of MS course. Disability status correlated with 1D measures, suggesting that serial evaluation of Evans and bifrontal ratios might contribute to the radiological evaluation of MS patients.

Bolus compared with continuous infusion of microbubble contrast agent using real-time contrast harmonic imaging ultrasound in breast tumors.

BACKGROUND: Contrast-enhanced ultrasound (CEUS) has gained interest because of its ability to gather vascular information in various organs. There is still a matter of debate concerning its value in breast lesions. The method of choice on how to administer the contrast agent varies depending on the organ to be studied. Infusion of microbubbles is used in echocardiography, while bolus administration is the preferred technique for abdominal organs. PURPOSE: To compare-in equal doses-bolus versus continuous infusion of microbubbles, using real-time contrast harmonic imaging in breast tumors. MATERIAL AND METHODS: A total of 29 female patients (mean age 54 years) with either clear malignant or benign findings in the breast or axilla were included. Contrast harmonic imaging (CHI US) was performed with a Philips iU22 using an L9-3 MHz linear probe, especially designed for this purpose. A low mechanical index (0.06-0.07) was used to avoid massive destruction of the microbubbles. A dose of 2.4 ml of Sono Vue was first infused intravenously over 1 min with an infusion pump. After 10 min, the same dose was injected as a bolus over 2 s, followed by a flush of 10 ml of saline solution. Contrast uptakes by the tumors were recorded 2 min from the moment of injection, with both methods for each patient. RESULTS: Bolus administration of contrast agent provided a sharply demarcated enhancement and wash-out pattern for all lesions. The continuous infusion of the same contrast agent failed to show any wash-in/wash-out or time-to-peak/peak intensity phenomena in all cases. CONCLUSION: CEUS using real-time harmonic imaging in order to evaluate breast tumors should be performed with bolus administration of contrast agent in order to achieve better intensity/time curve outcomes.

Medial temporal lobe atrophy increases the specificity of cerebrospinal fluid biomarkers in Alzheimer disease with minor cerebrovascular changes.

BACKGROUND: Although cerebrospinal fluid (CSF) biomarkers and medial temporal lobe atrophy (MTA) contribute to the diagnosis of Alzheimer disease (AD), they may not be specific. Relatively little is known about how they correlate with each other. PURPOSE: To identify the validity of the radiological linear measurements of brain atrophy in AD diagnosis by examining the correlation with CSF biomarkers and by examining if specificity could be improved in classification of AD from controls, when the linear measurements are combined with the CSF biomarkers. MATERIAL AND METHODS: 59 controls (20 male/39 female, age 73+/-8 years), 162 pure AD patients (49/113, 74+/-7 years), and 86 AD patients with minor cerebrovascular changes (CVC) (31/55, 77+/-5 years), aged between 52 and 94 years, were recruited from the Malmo Alzheimer Study. AD patients were subgrouped into "pure AD" and "AD + CVC" in order to clarify the possible influence of CVC on atrophy or CSF biomarkers in AD patients. Abeta42, T-tau, and P-tau in CSF were examined. Computed tomography (CT) linear measurements were performed, which included temporal horn ratio and suprasellar cistern ratio that reflect MTA. RESULTS: Compared with the 14 significant correlations between the CT measurements and three CSF biomarkers in the pure AD group, there was only one significant correlation in the AD + CVC group and one in the control group. In particular, P-tau correlates with temporal horn ratio only in pure AD. When the CT measurements were added with CSF biomarkers as independent variables in discriminant analysis, the percentage of correct classification of AD + CVC from controls increased from 79.5% (only CSF biomarkers) to 84.6% (combined CT measurements with CSF biomarkers). However, little was changed in the pure AD group. CONCLUSION: P-tau correlates with the linear CT measure of MTA only in pure AD without CVC. Combined with the measure of MTA, the specificity of CSF biomarkers can be increased, but only in AD + CVC. The linear measurements of MTA are of value in AD diagnosis.

Rate of ventricular enlargement in multiple sclerosis: a nine-year magnetic resonance imaging follow-up study.

BACKGROUND: In multiple sclerosis (MS), brain atrophy assessed by linear measurements of ventricular widths has been reported to be well correlated with three-dimensional (3D) measurements. Therefore, serial linear measurements with no need for advanced 3D evaluation may be proven to be robust markers of irreversible, destructive changes. PURPOSE: To evaluate the rate of supratentorial ventricular enlargement representing four decades of disease span. MATERIAL AND METHODS: 37 MS patients with disease duration at baseline ranging from 1 to 33 years were included. The mean time of the individual magnetic resonance imaging (MRI) follow-up was 9.25 years (range 7.3-10 years). Enlargement rate of the third and lateral ventricles was studied over time by applying three linear measurements on axial 5-mm T1-weighted MRI images. RESULTS: Progression of supratentorial ventricular widths during 9 years' follow-up was found. The mean annual width increase of the third ventricle was 0.20 mm (P<0.001, 95% confidence interval [CI] 0.15-0.25), for the frontal horn width 0.32 mm (P<0.001, 95% CI 0.23-0.40), and increase of the intercaudate distance was 0.26 mm (P<0.001, 95% CI 0.19-0.33). The association between these three measurements and disability status persisted at the time of follow-up. CONCLUSION: We found uniform ventricular enlargement progression during four decades of disease span, suggesting unchanging total brain atrophy progression over time.

Contrast medium dose-to-GFR ratio: a measure of systemic exposure to predict contrast-induced nephropathy after percutaneous coronary intervention.

BACKGROUND: The contrast medium (CM) dose-to-eGFR (estimated glomerular filtration rate) ratio has recently been advocated to express systemic exposure to CM in assessing the risk of contrast medium-induced nephropathy (CIN). PURPOSE: To evaluate how CIN risk might vary with decreasing eGFR at fixed CM-dose/eGFR ratios and other CIN risk factors, and to find a relatively safe CM-dose/eGFR ratio. MATERIAL AND METHODS: 391 patients underwent primary coronary angioplasty for ST-segment elevation acute myocardial infarction. CM dose (grams iodine; g I), eGFR (ml/min), and preprocedural CIN risk factors were entered into a multiple logistic regression model. From the established statistical model, the probability of CIN (>or=44.2 micromol/l serum creatinine rise or oliguria/anuria) was calculated at various eGFR levels based on g-I/eGFR ratios of 1:2, 1:1, 2:1, and 3:1. RESULTS: At a g-I/eGFR ratio <1 the risk of CIN was 3%, while it was 25% at a g-I/eGFR ratio >or=1. Independent predictors of CIN were CM dose, eGFR, left ventricular ejection fraction (LVEF) and cardiogenic shock (ROC area =0.87). An estimated CIN risk of 10% would for example occur at a g-I/eGFR ratio of 1.5:1 in patients with 50% LVEF without shock. At a 1:2, 1:1, 2:1, and 3:1 g-I/eGFR ratio with 50% LVEF without shock, the CIN risk was about 2, 6, 18, and 30%, respectively, over a wide range of eGFR values (30-90 ml/min). At a 1:1 g-I/eGFR ratio with 50% LVEF+shock, 25% LVEF without shock, or 25% LVEF+shock, the CIN risk was 20, 55, and 80%, respectively. CONCLUSION: Relating CM dose to eGFR appears to be an attractive pharmacotoxic model to assess CIN risk. At fixed CM-dose/eGFR ratios, CIN risk increased marginally with decreasing eGFR. Limiting the CM dose in g I numerically to the eGFR value in ml/min or less may be relatively safe with regard to CIN, unless multiple risk factors are present.

Role of scintigraphy with technetium-99m depreotide in the diagnosis and management of patients with suspected lung cancer.

BACKGROUND: In Sweden, there are over 3000 new lung cancer cases every year. There are still numerous patients with undetermined lesions after routine diagnostic evaluation by clinical examination, chest radiography, computed tomography (CT) of the thorax, and bronchoscopy. An appropriate method for further diagnostic workup is therefore needed. PURPOSE: To evaluate the diagnostic value of the somatostatin analogue depreotide in patients with suspected lung cancer, and to determine in which clinical settings it would be beneficial to use 99mTc-depreotide scintigraphy. MATERIAL AND METHODS: We included 99 consecutive patients referred to our hospital with suspected lung cancer. A clinical examination, bronchoscopy, chest radiography, CT of the thorax and upper abdomen, and scintigraphy were done. Scintigraphy was performed after injection of 740 MBq (99m)Tc depreotide with tomographical imaging of the thorax and whole-body scanning. The diagnostic outcome of the scintigrams was compared to CT, using morphology or clinical outcome as the endpoint. RESULTS: 99mTc-depreotide uptake was found in 62 out of 66 malignancies, including 57 of 58 primary lung cancer cases. Two cases of lung metastasis (one from a colon cancer and one from an adenoid cystic carcinoma originating in the palate) and one rib chondrosarcoma did not show depreotide uptake. There were 33 patients with benign lesions, of whom 16 displayed false-positive 99mTc-depreotide uptake, whereof 11 were pneumonias. Tc-99m-depreotide uptake was absent in 17 patients with benign lesions, including all 10 hamartomas. The sensitivity in detecting malignancy was 94%, and in detecting lung cancer 98%. The specificity was calculated based on two sets of data. When all cases were used, the specificity was 52%. If the 12 pneumonias are excluded, the specificity was 77%. CONCLUSION: 99mTc-depreotide scintigraphy has a high sensitivity in detecting lung cancer. The method is useful in decision-making with respect to surgery.

Usefulness of computed tomography linear measurements in diagnosing Alzheimer's disease.

BACKGROUND: Medial temporal lobe atrophy (MTA) is an early sign of Alzheimer's disease (AD). The current method of choice for measuring MTA is volumetric measurement based on 3D magnetic resonance imaging (MRI), but this complicated method has not been implemented clinically. PURPOSE: To investigate whether simple computed tomography (CT) linear measurements of the brain could be of value in AD workup. MATERIAL AND METHODS: Fifty-nine healthy control subjects and 248 AD subjects were recruited. They were evaluated using a comprehensive clinical workup. A series of linear CT measurements were obtained from brain CT. RESULTS: In discriminant analysis, the temporal horn ratio and the suprasellar cistern ratio were the atrophy factors that contributed most significantly to the diagnoses. Combined with other clinical factors (apolipoprotein E4 genotype), a correct AD classification of 90.2% was achieved. CONCLUSION: CT linear measurements could be of value in the workup of AD patients, considering the inexpensiveness and availability of CT as well as the simplicity of linear measurements.

Parameters obtained by hepatobiliary scintigraphy have significant correlation with biochemical factors early after liver transplantation.

BACKGROUND: Early postoperative hepatobiliary scintigraphy after liver transplantation is performed worldwide, but data on its significance for graft function are currently limited. PURPOSE: To examine the correlation between the result of early postoperative hepatobiliary scintigraphy and pre- and postoperative biochemical parameters in liver transplantation (LTx) patients. MATERIAL AND METHODS: Six parameters of hepatobiliary scintigraphy using (99m)Tc mebrofenin were statistically analyzed in 108 LTx patients: 1) half-life of the activity of elimination of mebrofenin from the blood; 2) total clearance of mebrofenin from the blood due to all possible routes; 3) half-life of the activity due to liver uptake; 4) clearance of mebrofenin from the blood due to liver uptake; 5) time to maximal uptake in the liver; and 6) the hepatic extraction fraction (HEF) and biochemical data. Analysis between patients with preoperative normal liver function, familial amyloid polyneuropathy (FAP), and end-stage liver disease (non-FAP) was also performed. RESULTS: Univariate and multivariate analysis revealed that total bilirubin postoperative day 3 correlated with all three scintigraphic parameters, and peak aspartate aminotransferase and alanine aminotransferase correlated with HEF. The analysis between patients with FAP and non-FAP revealed no significant difference of scintigraphic data between the two groups. CONCLUSION: A significant correlation between early postoperative scintigraphic results and biochemical parameters was demonstrated.

Standard orientation of the pelvis: validation on a model and ten patients.

PURPOSE: To validate an image post-processing method for re-orienting the pelvis in CT volumes to a standardized orientation in a model and in 10 patients. MATERIAL AND METHODS: Twenty-four CT volumes of a pelvic model and 10 pairs of postoperative total hip arthroplasty (THA) patient CT scans were rotated to a defined pelvic standard orientation and the rotation was recorded. For precision, a test-retest procedure was used. For accuracy, three exactly represented coordinate points were used. For clinical application, the standard orientation was used for calculating the direction of acetabular cup migration from a previous model study. RESULTS: Precision of pelvic standard orientation, calculated as maximal directional error, was better than 1 degrees in the model study and better than 1.5 degrees in the patient study. Accuracy, expressed as angle between ideal and measured coordinate axes, was 0.1 degrees for x, y, z axes. No measurable systematic errors were found. When applied to acetabular cup migration in the model, standardization of pelvic orientation had no significant effect on the measurements. CONCLUSION: Reorienting the pelvis during image post-processing was shown to be accurate. It enables measurements relative to the pelvis and minimizes the dependency of patient positioning.

Adjunctive diagnostic value of targeted electrical impedance imaging to conventional methods in the evaluation of breast lesions.

PURPOSE: To determine the diagnostic accuracy of targeted electrical impedance imaging in characterizing breast lesions, and to evaluate whether lesion size, depth and histopathology affect the diagnosis. MATERIAL AND METHODS: A total of 137 women with 145 lesions (79 malignant and 66 benign) found by palpation or mammography were prospectively enrolled in this study. The patients were examined by means of clinical breast examination, mammography, ultrasonography, and electrical impedance imaging with TransScan TS2000. A level of suspicion (LOS) post-processing algorithm (v2.67) was used for TS2000 lesion assessment. Imaging findings were correlated with cytologic (n=54) and histologic diagnoses (n=91). Patients with benign lesions were followed up for a mean of 36 months. RESULTS: TS2000 showed a high sensitivity (86%) which did not differ significantly from that of mammography (87%) and ultrasonography (US) (75%). The specificity of TS2000 (49%) was significantly lower compared to mammography (97%, P<0.0001) and US (100%, P<0.0001). The additive use of TS2000 to mammography and US yielded no significant increase in sensitivity (97%), but the decrease in specificity was significant (46%, P<0.0001). Diagnostic effectiveness of TS2000 (Az=0.68), as measured by the area under the ROC curve, was significantly lower than for mammography (Az=0.93, P<0.0001) and for US (Az=0.91, P<0.0001). When using TS2000 in addition to mammography and US (Az=0.86), a significant impairment was found (P=0.0003). CONCLUSION: The role of targeted electrical impedance imaging as an adjunct to mammography and ultrasonography in the diagnosis of breast lesions is not justified by the result of this study.

Contrast-medium-Induced nephropathy correlated to the ratio between dose in gram iodine and estimated GFR in ml/min.

PURPOSE: To suggest a more precise tool when assessing the risk of contrast-medium-induced nephropathy (CIN), i.e. the ratio between contrast medium (CM) dose expressed in grams of iodine (g-I) and estimated glomerular filtration rate in ml/min (eGFR; based on equations using serum-creatinine (s-Cr), weight, height, age, and/or sex), here named I-dose/GFR ratio. MATERIAL AND METHODS: A Medline search of published CIN investigations reporting mean eGFR and mean dose of low-osmolality CM (LOCM) identified 10 randomized controlled prophylactic and 2 cohort coronary investigations, and 3 randomized and 1 cohort computed tomographic (CT) investigation. From the randomized trials, data were collected only from the placebo or control arms, unless there was no significant difference between the control and test groups. The mean I-dose/GFR ratio of each study was correlated with the mean frequency of CIN-1 (s-Cr rise> or =44.2 micromol/l or > or =20-25%) and CIN-2 (oliguria or requiring dialysis). A maximum dose according to an I-dose/GFR ratio= 1 in patients with s-Cr ranging from 100 to 300 micromol/l was compared with that of CIGARROA'S formula and with a "European consensus" threshold published by the European Society of Urogenital Radiology, both using s-Cr alone to predict renal function. McCullough's formula was used to assess the risk of CIN requiring dialysis at an I-dose/GFR ratio= 1 with LOCM. RESULTS: The coronary investigations revealed a linear correlation with a correlation coefficient between the I-dose/GFR ratio and the frequency of CIN-1 and CIN-2 of 0.91 (P<0.001) and 0.84 (P=0.001), respectively. At a mean I-dose/GFR ratio= 1, the regression line indicated a 10%) risk of CIN-1 and a 1% risk of CIN-2. At a mean I-dose/ GFR ratio=3, the risk of CIN-1 and CIN-2 increased to about 50% and 15%, respectively. Pooled weighted data from the CT investigations revealed a 12% risk of CIN-1 at a mean I-dose/GFR ratio = 1.1 and no cases of CIN-2. The maximum CM dose according to an I-dose/GFR ratio= 1 was about 30-50% of that of both Cigarroa's formula and the "European consensus" in elderly low-weight individuals, while it was similar for middle-aged individuals weighing about 90 kg. McCullough's formula suggests that there will be an exponentially increasing risk of CIN requiring dialysis, but at an I-dose/GFR ratio= 1 and using LOCM it will not exceed 1% until GFR decreases below 30 ml/min in diabetics and below 20 ml/min in non-diabetics. CONCLUSION: Using the I-dose/GFR ratio may be a more expedient way of improving risk assessment of CIN than today's common practice of estimating CM dose from volume alone and renal function from s-Cr alone. Prospective studies based on individual patient data are encouraged to define the risk of CIN at various I-dose/GFR ratios and correlated to type of CM, examination, risk factors, etc.