Lars Edenbrandt

Lund University, Lund, Skåne, Sweden

Are you Lars Edenbrandt?

Claim your profile

Publications (155)285.69 Total impact

  • European Urology Supplements 11/2014; · 3.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Assessment of image analysis methods and computer software used in 99mTc-MAG3 dynamic renography is important to ensure reliable study results and ultimately the best possible care for patients. In this work, we present a national multicentre study of the quantification accuracy in 99mTc-MAG3 renography, utilizing virtual dynamic scintigraphic data obtained by Monte Carlo-simulated scintillation camera imaging of digital phantoms with time-varying activity distributions. Three digital phantom studies were distributed to the participating departments, and quantitative evaluation was performed with standard clinical software according to local routines. The differential renal function (DRF) and time to maximum renal activity (Tmax) were reported by 21 of the 28 Swedish departments performing 99mTc-MAG3 studies as of 2012. The reported DRF estimates showed a significantly lower precision for the phantom with impaired renal uptake than for the phantom with normal uptake. The Tmax estimates showed a similar trend, but the difference was only significant for the right kidney. There was a significant bias in the measured DRF for all phantoms caused by different positions of the left and right kidney in the anterior–posterior direction. In conclusion, this study shows that virtual scintigraphic studies are applicable for quality assurance and that there is a considerable uncertainty associated with standard quantitative parameters in dynamic 99mTc-MAG3 renography, especially for patients with impaired renal function.
    Clinical Physiology and Functional Imaging 10/2014; · 1.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A bone scan is a common method for monitoring bone metastases in patients with advanced prostatecancer. The Bone Scan Index (BSI) measures the tumor burden on the skeleton, expressed as apercentage of the total skeletal mass. Previous studies have shown that BSI is associated withsurvival of prostate cancer patients. The objective in this study was to investigate to what extentregional BSI measurements, as obtained by an automated method, can improve the survival analysisfor advanced prostate cancer.
    BMC Medical Imaging 07/2014; 14(1):24. · 1.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to investigate the diagnostic ability of a completely automated computer-assisted diagnosis (CAD) system to detect metastases in bone scans by two patterns: one was per region, and the other was per patient. This study included 406 patients with suspected metastatic bone tumors who underwent whole-body bone scans that were analyzed by the automated CAD system. The patients were divided into four groups: a group with prostatic cancer (N = 71), breast cancer (N = 109), males with other cancers (N = 153), and females with other cancers (N = 73). We investigated the bone scan index and artificial neural network (ANN), which are parameters that can be used to classify bone scans to determine whether there are metastases. The sensitivities, specificities, positive predictive value (PPV), negative predictive value (NPV), and accuracies for the four groups were compared. Receiver operating characteristic (ROC) analyses of region-based ANN were performed to compare the diagnostic performance of the automated CAD system. There were no significant differences in the sensitivity, specificity, or NPV between the four groups. The PPVs of the group with prostatic cancer (51.0 %) were significantly higher than those of the other groups (P < 0.01). The accuracy of the group with prostatic cancer (81.5 %) was significantly higher than that of the group with breast cancer (68.6 %) and the females with other cancers (65.9 %) (P < 0.01). For the evaluation of the ROC analysis of region-based ANN, the highest Az values for the groups with prostatic cancer, breast cancer, males with other cancers, and females with other cancers were 0.82 (ANN = 0.4, 0.5, 0.6, 0.7, and 0.8), 0.83 (ANN = 0.7), 0.81 (ANN = 0.5), and 0.81 (ANN = 0.6), respectively. The special CAD system "BONENAVI" trained with a Japanese database appears to have significant potential in assisting physicians in their clinical routine. However, an improved CAD system depending on the primary lesion of the cancer is required to decrease the proportion of false-positive findings.
    Annals of Nuclear Medicine 02/2014; · 1.41 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The European Society of Cardiology recommends that patients with >10% area of ischemia should receive revascularization. We investigated inter-observer variability for the extent of ischemic defects reported by different physicians and by different software tools, and if inter-observer variability was reduced when the physicians were provided with a computerized suggestion of the defects. Twenty-five myocardial perfusion single photon emission computed tomography (SPECT) patients who were regarded as ischemic according to the final report were included. Eleven physicians in nuclear medicine delineated the extent of the ischemic defects. After at least two weeks, they delineated the defects again, and were this time provided a suggestion of the defect delineation by EXINI HeartTM (EXINI). Summed difference scores and ischemic extent values were obtained from four software programs. The median extent values obtained from the 11 physicians varied between 8% and 34%, and between 9% and 16% for the software programs. For all 25 patients, mean extent obtained from EXINI was 17.0% (+/- standard deviation (SD) 14.6%). Mean extent for physicians was 22.6% (+/- 15.6%) for the first delineation and 19.1% (+/- 14.9%) for the evaluation where they were provided computerized suggestion. Intra-class correlation (ICC) increased from 0.56 (95% confidence interval (CI) 0.41-0.72) to 0.81 (95% CI 0.71-0.90) between the first and the second delineation, and SD between physicians were 7.8 (first) and 5.9 (second delineation). There was large variability in the estimated ischemic defect size obtained both from different physicians and from different software packages. When the physicians were provided with a suggested delineation, the inter-observer variability decreased significantly.
    BMC Medical Imaging 01/2014; 14(1):5. · 1.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this myocardial perfusion imaging (MPI) study was to compare the diagnostic performance of two computer-aided diagnosis (CAD) systems, EXINI Heart(TM) (EXINI), and PERFEX(TM) (PERFEX) Emory Cardiac Toolbox (ECT), and the summed stress score (SSS) values from both software packages. We studied 1,052 consecutive patients who underwent 2-day stress/rest (99m)Tc-sestamibi MPI studies. The reference standard classifications for the MPI studies were obtained from three experienced physicians who separately classified all cases regarding the presence or absence of ischemia and/or infarction. Automatic processing was carried out using EXINI and PERFEX to obtain CAD results and SSS values based on the 17-segment model. The three experts' classifications showed ischemia in 257 patients and abnormal studies, i.e., either ischemia or infarction or both, in 318 patients. Accuracy was significantly higher in EXINI than in PERFEX, regarding both the detection of ischemia (87.4 vs 77.6%; P < 0.0001) and the detection of abnormal studies (91.6 vs 67.9%; P < 0.0001). EXINI's CAD system showed a higher specificity than its SSS values (86.8 vs 73.6%; P < 0.0001) at the same level of sensitivity. EXINI demonstrated greater diagnostic accuracy for detection of ischemia and abnormal studies than did PERFEX. EXINI CAD also outperformed its SSS analysis.
    Journal of Nuclear Cardiology 01/2014; · 2.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction Drug development and clinical decision making for patients with metastatic prostate cancer (PC) have been hindered by a lack of quantitative methods of assessing changes in bony disease burden that are associated with overall survival (OS). Bone scan index (BSI), a quantitative imaging biomarker of bone tumor burden, is prognostic in men with metastatic PC. We evaluated an automated method for BSI calculation for the association between BSI over time with clinical outcomes in a randomized double-blind trial of tasquinimod (TASQ) in men with metastatic castration-resistant PC (mCRPC). Methods Bone scans collected during central review from the TASQ trial were analyzed retrospectively using EXINIboneBSI, an automated software package for BSI calculation. Associations between BSI and other prognostic biomarkers, progression-free survival, OS, and treatment were evaluated over time. Results Of 201 men (57 TASQ and 28 placebo), 85 contributed scans at baseline and week 12 of sufficient quality. Baseline BSI correlated with prostate-specific antigen and alkaline phosphatase levels and was associated with OS in univariate (hazard ratio [HR] = 1.42, P = 0.013) and multivariate (HR = 1.64, P<0.001) analyses. BSI worsening at 12 weeks was prognostic for progression-free survival (HR = 2.14 per BSI doubling, P<0.001) and OS (HR = 1.58, P = 0.033) in multivariate analyses including baseline BSI and TASQ treatment. TASQ delayed BSI progression. Conclusions BSI and BSI changes over time were independently associated with OS in men with mCRPC. A delay in objective radiographic bone scan progression with TASQ is suggested; prospective evaluation of BSI progression and response criteria in phase 3 trials of men with mCRPC is warranted.
    Urologic Oncology: Seminars and Original Investigations. 01/2014;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Bone Scan Index (BSI) is a quantitative measurement of tumour burden in the skeleton calculated from bone scan images. When analysed at the time of diagnosis, it has been shown to provide prognostic information on survival in men with metastatic prostate cancer (PCa). In this study, we evaluated the prognostic value of BSI during androgen deprivation therapy (ADT).
    EJNMMI research. 01/2014; 4:58.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Artificial neural network (ANN)-based bone scan index (BSI), a marker of the amount of bone metastasis, has been shown to enhance diagnostic accuracy and reproducibility but is potentially affected by training databases. The aims of this study were to revise the software using a large number of Japanese databases and to validate its diagnostic accuracy compared with the original Swedish training database. The BSI was calculated with EXINIbone (EB; EXINI Diagnostics) using the Swedish training database (n = 789). The software using Japanese training databases from a single institution (BONENAVI version 1, BN1, n = 904) and the revised version from nine institutions (version 2, BN2, n = 1,532) were compared. The diagnostic accuracy was validated with another 503 multi-center bone scans including patients with prostate (n = 207), breast (n = 166), and other cancer types. The ANN value (probability of abnormality) and BSI were calculated. Receiver operating characteristic (ROC) and net reclassification improvement (NRI) analyses were performed. The ROC analysis based on the ANN value showed significant improvement from EB to BN1 and BN2. In men (n = 296), the area under the curve (AUC) was 0.877 for EB, 0.912 for BN1 (p = not significant (ns) vs. EB) and 0.934 for BN2 (p = 0.007 vs. EB). In women (n = 207), the AUC was 0.831 for EB, 0.910 for BN1 (p = 0.016 vs. EB), and 0.932 for BN2 (p < 0.0001 vs. EB). The optimum sensitivity and specificity based on BN2 was 90% and 84% for men and 93% and 85% for women. In patients with prostate cancer, the AUC was equally high with EB, BN1, and BN2 (0.939, 0.949, and 0.957, p = ns). In patients with breast cancer, the AUC was improved from EB (0.847) to BN1 (0.910, p = ns) and BN2 (0.924, p = 0.039). The NRI using ANN between EB and BN1 was 17.7% (p = 0.0042), and that between EB and BN2 was 29.6% (p < 0.0001). With respect to BSI, the NRI analysis showed downward reclassification with total NRI of 31.9% (p < 0.0001). In the software for calculating BSI, the multi-institutional database significantly improved identification of bone metastasis compared with the original database, indicating the importance of a sufficient number of training databases including various types of cancers.
    EJNMMI research. 12/2013; 3(1):83.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The objective of this study was firstly to develop and evaluate an automated method for the detection of new lesions and changes in bone scan index (BSI) in serial bone scans and secondly to evaluate the prognostic value of the method in a group of patients receiving chemotherapy. The automated method for detection of new lesions was evaluated in a group of 266 patients using the classifications by three experienced bone scan readers as a gold standard. The prognostic value of the method was assessed in a group of 31 metastatic hormone-refractory prostate cancer patients who were receiving docetaxel. Cox proportional hazards were used to investigate the association between percentage change in BSI, number of new lesions and overall survival. Kaplan-Meier estimates of the survival function were used to indicate a significant difference between patients with an increase/decrease in BSI or those with two or more new lesions or less than two new lesions. The automated method detected progression defined as two or more new lesions with a sensitivity of 93% and a specificity of 87%. In the treatment group, both BSI changes and the number of new metastases were significantly associated with survival. Two-year survival for patients with increasing and decreasing BSI from baseline to follow-up scans were 18% and 57% (p = 0.03), respectively. Two-year survival for patients fulfilling and not fulfilling the criterion of two or more new lesions was 35% and 38% (n.s.), respectively. An automated method can be used to calculate the number of new lesions and changes in BSI in serial bone scans. These imaging biomarkers contained prognostic information in a small group of patients with prostate cancer receiving chemotherapy.
    EJNMMI research. 08/2013; 3(1):64.
  • Source
    Lars Edenbrandt, Mattias Ohlsson, Elin Trägårdh
    [Show abstract] [Hide abstract]
    ABSTRACT: Stress myocardial perfusion scintigraphy (MPS) is widely regarded as a useful imaging modality for diagnosing patients with suspected ischemic heart disease. Current European guidelines recommend stress study to be performed first since rest study can be omitted if stress study is interpreted as normal. Thus, a rest study should only be performed in patients with equivocal or abnormal studies. The aim of the present study was to investigate the prognosis of a normal stress-only MPS compared to a normal stress-rest MPS in a retrospective manner and also with regard to normal/abnormal left ventricular function data. All 4,820 patients who underwent 99mTc MPS at Skane University Hospital in Malmo, Sweden, in 2004 to 2007, for suspected or management of known ischemic heart disease were considered. The physician in clinical charge of the investigation decided whether a rest study was necessary or not. Based on the final report according to clinical routine, only patients with a normal perfusion study (no infarction or inducible ischemia) were included. The endpoints were non-fatal acute coronary syndrome or death from ischemic cardiac origin. A total of 3,426 patients with a normal perfusion study were included. Of these, 2,215 patients had a stress-only study and 1,211 patients had both stress and rest studies. Mean follow-up was 6.2 years. The lowest event rate was found in the normal stress-only group (0.56% for normal stress-only patients vs. 1.42% for normal stress-rest patients; p < 0.0001). When dividing patients according to sex and stress type, the best prognosis was also found in the normal stress-only group (p < 0.0001 for all comparisons). Regarding left ventricular function data, we did not find any significant difference in event rate between normal vs. abnormal ejection fraction (EF), normal vs. abnormal end-diastolic volume (EDV) or normal EF, and EDV vs. abnormal EF or EDV for either the normal stress-only patients or the normal stress-rest patients. Patients with a normal stress-only study had an excellent prognosis over a mean follow-up time of 6 years. Thus, omitting the rest study if the stress study is normal is a safe procedure.
    EJNMMI research. 07/2013; 3(1):58.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The need for age-adjusted and/or sex-adjusted reference values in dopamine transporter (DAT) and dopamine D2 receptor (D2R) imaging with single-photon emission computed tomography (SPECT) in a longitudinal study of parkinsonian diseases was investigated. We used two different image evaluation tools with a cross-sectional and longitudinal statistical approach. Baseline DAT and/or D2R SPECT were performed in 51 healthy controls (HC), age-matched to patients in an ongoing prospective study on idiopathic parkinsonism. Twenty-four HC were re-examined after 3 years and 21 HC were examined again after 5 years. SPECT was performed with I-FP-Cit and I-IBZM on a two-headed hybrid gamma camera. Regions of interest and volumes of interest (VOIs) were used for image evaluation. A cross-sectional and longitudinal statistical analysis was carried out. Fewer sex-based differences and less age dependency were seen in DAT SPECT uptake ratios compared with D2R SPECT uptake ratios and when comparing uptake ratios obtained with regions of interest against those with VOIs. In the cross-sectional analysis, a significant age-dependent decline was seen in women in both DAT and D2R uptakes with the VOI method but not in men with either evaluation method. In the longitudinal dataset, both a slight decline and increase over time were seen in DAT uptake; however, a general pattern of decrease was seen in both men and women in D2R uptake. The choice of the image evaluation method can influence the pattern of sex-based and age-related differences. The results speak for the use of age-stratified reference values for women, in particular when using a VOI method.
    Nuclear Medicine Communications 07/2013; · 1.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE: In patients with a small heart, defined as an end-systolic volume (ESV) of ≤20 mL calculated using the Quantitative Gated SPECT (QGS) program, underestimation of ESV and overestimation of ejection fraction (EF) using gated myocardial perfusion imaging are considered errors caused by inappropriate delineation of the left ventricle (LV). The aim of this study was to develop a new method for delineation of the LV and to evaluate it in studies using a digital phantom, normal subjects and patients. METHODS: The active shape-based method for LV delineation, EXINI heart (ExH), was adjusted to more accurately process small hearts. In small hearts, due to the partial volume effect and the short distance to the opposite ventricular wall, the endocardial and the epicardial surfaces are shifted in the epicardial direction depending on the midventricular volume. The adjusted method was evaluated using digital XCAT phantoms with Monte Carlo simulation (8 virtual patients), a Japanese multicentre normal database (69 patients) and consecutive Japanese patients (116 patients). The LV volumes, EF and diastolic parameters derived from ExH and QGS were compared. RESULTS: The digital phantom studies showed a mean ESV of 87 % ± 9 % of the true volume calculated using ExH and 22 % ± 18 % calculated using QGS. In the normal database, QGS gave higher EFs in women than in men (71.4 ± 6.0 % vs. 67.2 ± 6.0 %, p = 0.0058), but ExH gave comparable EFs (70.7 ± 4.9 % and 71.4 ± 5 % in men and women, respectively, p = ns). QGS gave higher EFs in subjects with a small heart than in those with a normal-sized heart (74.5 ± 5.1 % vs. 66.1 ± 4.9 %), but ExH gave comparable values (70.0 ± 5.9 % vs. 71.6 ± 4.2 %, respectively, p = ns). In consecutive patients, the average EFs with QGS in patients with ESV >20 mL, 11-20 mL and ≤10 mL were 57.9 %, 71.9 % and 83.2 %, but with ExH the differences among these groups were smaller (65.2 %, 67.8 % and 71.5 %, respectively). CONCLUSION: The volume-dependent edge correction algorithm was able to effectively reduce the effects on ESV and EF of a small heart. The uniform normal values might be applicable to both men and women and to both small and normal-sized hearts.
    European Journal of Nuclear Medicine 04/2013; · 4.53 Impact Factor
  • Source
    Elin Trägårdh, Sven Valind, Lars Edenbrandt
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: The American Society of Nuclear Cardiology and the Society of Nuclear Medicine conclude that incorporation of attenuation corrected (AC) images in myocardial perfusion scintigraphy (MPS) will improve diagnostic accuracy. The aim was to investigate the value of adding AC stress-only images for the decision whether a rest study is necessary or not. METHODS: 1,261 patients admitted to 99mTc MPS were studied. The stress studies were interpreted by two physicians who judged each study as "no rest study necessary" or "rest study necessary", by evaluating NC stress-only and NC + AC stress-only images. When there was disagreement between the two physicians, a third physician evaluated the studies. Thus, agreement between 2 out of 3 physicians was evaluated. RESULTS: The physicians assessed 214 more NC + AC images than NC images as "no rest study necessary" (17% of the study population). The number of no-rest-study-required was significantly higher for NC + AC studies compared to NC studies (859 vs 645 cases (p < 0.0001). In the final report according to clinical routine, ischemia or infarction was reported in 23 patients, assessed as "no rest study necessary" (22 NC + AC cases; 8 NC cases), (no statistically significant difference). In 11 of these, the final report stated "suspected/possible ischemia or infarction in a small area". CONCLUSIONS: Adding AC stress-only images to NC stress-only images reduce the number of unnecessary rest studies substantially.
    BMC Medical Imaging 04/2013; 13(1):14. · 1.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Technetium-labeled agents, which are most often used for assessing myocardial perfusion in myocardial perfusion scintigraphy (MPS), are cleared by the liver and excreted by the biliary system. Spillover from extra-cardiac activity into the myocardium, especially the inferior wall, might conceal defects and lower the diagnostic accuracy of the study. The objective was to determine rules of thumb for when reacquisition is useful due to high extra-cardiac uptake, i.e., when interpretation of the studies was affected by poor image quality. METHODS: Patients admitted to MPS at any of the three study sites, who also underwent a reacquisition due to high extra-cardiac uptake were included. Image quality was assessed by ten technologists on a scale ranging from 1 to 5. Interpretations regarding the presence/absence of ischemia/infarction, including the certainty of the diagnosis, were made by three physicians. RESULTS: There was a statistically significant increase in image quality between the first and the repeated acquisition (1,256 cases of increased quality at the repeated study (66%), 134 cases of decreased quality at the repeated study (7%), 510 cases of unchanged quality (27%) P < 0.0001). The number of equivocal studies, interpreted by physicians, decreased when evaluating the repeated studies compared to the first studies for all physicians, both for the interpretations of ischemia and for infarction. Receiver operating characteristic analyses revealed that for both endpoints (ischemia, infarction) and all physicians, the optimal cutoff point for performing a reacquisition was between quality categories 2 and 3. CONCLUSION: This study indicates that repeat acquisition is useful when (1) the intensity of the extra-cardiac uptake is equal to or higher than the cardiac uptake when there is no separation between the extra-cardiac uptake and the inferior cardiac wall and (2) when the intensity of the extra-cardiac uptake is higher than the cardiac uptake when there is a separation between the extra-cardiac uptake and the inferior wall of less than one cardiac wall.
    EJNMMI research. 03/2013; 3(1):20.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: The objective of this study was to explore the prognostic value of the Bone Scan Index (BSI) obtained at the time of diagnosis in a group of high-risk prostate cancer patients receiving primary hormonal therapy. METHODS: This was a retrospective study based on 130 consecutive prostate cancer patients at high risk, based on clinical stage (T2c/T3/T4), Gleason score (8 to 10) and prostate-specific antigen (PSA) (>20 ng/mL), who had undergone whole-body bone scans <3 months after diagnosis and who received primary hormonal therapy. BSI was calculated using an automated method. Cox proportional-hazards regression models were used to investigate the association between clinical stage, Gleason score, PSA, BSI and survival. Discrimination between prognostic models was assessed using the concordance index (C-index). RESULTS: In a multivariate analysis, Gleason score (p = 0.01) and BSI (p < 0.001) were associated with survival, but clinical stage (p = 0.29) and PSA (p = 0.57) were not prognostic. The C-index increased from 0.66 to 0.71 when adding BSI to a model including clinical stage, Gleason score and PSA. The 5-year probability of survival was 55% for patients without metastases, 42% for patients with BSI < 1, 31% for patients with BSI = 1 to 5, and 0% for patients with BSI > 5. CONCLUSIONS: BSI can be used as a complement to PSA to risk-stratify high-risk prostate cancer patients at the time of diagnosis. This imaging biomarker, reflecting the extent of metastatic disease, can be of value both in clinical trials and in patient management when deciding on treatment.
    EJNMMI research. 02/2013; 3(1):9.
  • Elin Trägårdh, Karl Sjöstrand, Lars Edenbrandt
    [Show abstract] [Hide abstract]
    ABSTRACT: Commercial normal stress databases in myocardial perfusion scintigraphy (MPS) commonly consist of 30-40 individuals. The aim of the study was to determine how many subjects are needed. Four normal stress databases were developed using patients who underwent 99mTc MPS: non-corrected images (NC) for male, NC for female, attenuation-corrected images (AC) for male and AC for female subjects. 126 male and 205 female subjects were included. The normal database was created by alternatingly computing the mean of all normal subjects and normalizing the subjects with respect to this mean, until convergence. Coefficients of variation (CV) were created for increasing number of included patients in the four different normal stress databases. Normal stress databases with < 35 subjects had a high CV. Mean CV -2 standard deviations (SD) decreased with 28% between two and five included subjects, 71% between two and 35 subjects and 83% between two and 100 included subjects for NC man. We conclude that the commonly used 30-40 individuals for making a normal stress database might not be enough due to the high CV. We propose that normal stress databases should consist of more than 30-40 individuals, preferably more than 50 individuals, both for NC and AC studies.
    Clinical Physiology and Functional Imaging 11/2012; 32(6):455-62. · 1.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In myocardial perfusion scintigraphy (MPS), typically a stress and a rest study is performed. If the stress study is considered normal, there is no need for a subsequent rest study. The aim of the study was to determine whether nuclear medicine technologists are able to assess the necessity of a rest study. Gated MPS using a 2-day 99mTc protocol for 121 consecutive patients were studied. Visual interpretation by 3 physicians was used as gold standard for determining the need for a rest study based on the stress images. All nuclear medicine technologists performing MPS had to review 82 training cases of stress MPS images with comments regarding the need for rest studies, and thereafter a test consisting of 20 stress MPS images. After passing this test, the nuclear medicine technologists in charge of a stress MPS study assessed whether a rest study was needed or not or if he/she was uncertain and wanted to consult a physician. After that, the physician in charge interpreted the images and decided whether a rest study was required or not. The nuclear medicine technologists and the physicians in clinical routine agreed in 103 of the 107 cases (96%) for which the technologists felt certain regarding the need for a rest study. In the remaining 14 cases the technologists were uncertain, i.e. wanted to consult a physician. The agreement between the technologists and the physicians in clinical routine was very good, resulting in a kappa value of 0.92. There was no statistically significant difference in the evaluations made by technicians and physicians (P = 0.617). The nuclear medicine technologists were able to accurately determine whether a rest study was necessary. There was very good agreement between nuclear medicine technologists and physicians in the assessment of the need for a rest study. If the technologists can make this decision, the effectiveness of the nuclear medicine department will improve.
    BMC Medical Informatics and Decision Making 09/2012; 12:97. · 1.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Automated segmentation of the skeleton is the first step for quantitative analysis and computer-aided diagnosis (CAD) of whole-body bone scans. The purpose of this study was to examine the influence of differences in skeletal atlas on the automated segmentation of skeletons in a Japanese patient group. The study was based on a bone scan CAD system that included a skeletal atlas obtained using 10 normal bone scans from European patients and 23 normal bone scans from Japanese patients. These were incorporated into the CAD system. The performance of the skeletal segmentation, based on either the European or the Japanese Atlas, was evaluated independently by three observers in a group of 50 randomly selected bone scans from Japanese patients. The skeletal segmentation was classified as correct in 41-44 of the 50 cases by the three observers using the Japanese atlas. The corresponding results were 15-18 of the 50 cases using the European atlas, and this difference was statistically significant (P<0.001). The anatomical areas most commonly classified as not correct were the skull, cervical vertebrae, and ribs. Automated segmentation of the skeleton in a Japanese patient group was more successful when the CAD system based on a Japanese atlas was used than when the corresponding system based on a European atlas was used. The results of this study indicate that it is of value to use a skeletal atlas based on normal Japanese bone scans in a CAD system for Japanese patients.
    Nuclear Medicine Communications 07/2012; 33(9):947-53. · 1.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Computer-aided diagnosis (CAD) software for bone scintigrams have recently been introduced as a clinical quality assurance tool. The purpose of this study was to compare the diagnostic accuracy of two CAD systems, one based on a European and one on a Japanese training database, in a group of bone scans from Japanese patients. The two CAD software are trained to interpret bone scans using training databases consisting of bone scans with the desired interpretation, metastatic disease or not. One software was trained using 795 bone scans from European patients and the other with 904 bone scans from Japanese patients. The two CAD softwares were evaluated using the same group of 257 Japanese patients, who underwent bone scintigraphy because of suspected metastases of malignant tumors in 2009. The final diagnostic results made by clinicians were used as gold standard. The Japanese CAD software showed a higher specificity and accuracy compared to the European CAD software [81 vs. 57 % (p < 0.05) and 82 vs. 61 % (p < 0.05), respectively]. The sensitivity was 90 % for the Japanese CAD software and 83 % for the European CAD software (n.s). The CAD software trained with a Japanese database showed significantly higher performance than the corresponding CAD software trained with a European database for the analysis of bone scans from Japanese patients. These results could at least partly be caused by the physical differences between Japanese and European patients resulting in less influence of attenuation in Japanese patients and possible different judgement of count intensities of hot spots.
    Annals of Nuclear Medicine 06/2012; 26(8):622-6. · 1.41 Impact Factor

Publication Stats

2k Citations
285.69 Total Impact Points

Institutions

  • 1988–2014
    • Lund University
      • • Department of Clinical Sciences
      • • Department of Theoretical Physics
      • • Department of Medical Radiation Physics
      • • Department of Clinical Physiology
      • • Department of Cardiology
      Lund, Skåne, Sweden
  • 2013
    • Kanazawa Medical University
      Kanazawa, Ishikawa, Japan
  • 2011–2013
    • Skåne University Hospital
      Malmö, Skåne, Sweden
  • 2005–2013
    • Sahlgrenska University Hospital
      • Department of Cardiology
      Goeteborg, Västra Götaland, Sweden
  • 2012
    • Kanazawa University
      • School of Health Sciences
      Kanazawa, Ishikawa, Japan
    • Gunma Prefectural Cancer Center
      Maebashi, Gunma Prefecture, Japan
  • 2008–2012
    • University of Gothenburg
      • Department of Molecular and Clinical Medicine
      Goeteborg, Västra Götaland, Sweden
  • 2003–2008
    • Malmö University
      Malmö, Skåne, Sweden
  • 2006
    • Helsingborgs Lasarett
      Hälsingborg, Skåne, Sweden
  • 1998
    • University of Plymouth
      Plymouth, England, United Kingdom
  • 1994
    • University of Glasgow
      Glasgow, Scotland, United Kingdom