Search

Background: The presence of malignant cells in bone biopsies is considered gold standard to verify occurrence of cancer, whereas a negative bone biopsy can represent a false negative, with a risk of increasing patient morbidity and mortality and creating misleading conclusions in cancer research. However, a paucity of literature documents the validity of negative bone biopsy as an exclusion criterion for the presence of skeletal malignancies.Purpose: To investigate the validity of a negative bone biopsy in bone lesions suspicious of malignancy.Material and Method: A retrospective cohort of 215 consecutive targeted non-malignant skeletal biopsies from 207 patients (43% women, 57% men, median age 64, and range 94) representing suspicious focal bone lesions, collected from January 1, 2011, to July 31, 2013, was followed over a 2-year period to examine any additional biopsy, imaging, and clinical follow-up information to categorize the original biopsy as truly benign, malignant, or equivocal. Standard deviations and 95% confidence intervals were calculated.Results: 210 of 215 biopsies (98%; 95% CI 0.94-0.99) showed to be truly benign 2 years after initial biopsy. Two biopsies were false negatives (1%; 95% CI 0.001-0.03), and three were equivocal (lack of imaging description).Conclusion: Our study documents negative bone biopsy as a valid criterion for the absence of bone metastasis. Since only 28% had a confirmed diagnosis of prior cancer and not all patients received adequately sensitive imaging, our results might not be applicable to all cancer patients with suspicious bone lesions.

The aim of this systematic review is to provide an overview of the use of Four-Dimensional Magnetic Resonance Imaging of vector blood flow (4D Flow MRI) in the abdominal veins. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in MEDLINE, Cochrane Library, EMBASE, and Web of Science. Quality assessment of the included studies was performed using the QUADAS-2 tool. The initial search yielded 781 studies and 21 studies were included. All studies successfully applied 4D Flow MRI in abdominal veins. Four-Dimensional Flow MRI was capable of discerning between healthy subjects and patients with cirrhosis and/or portal hypertension. The visual quality and inter-observer agreement of 4D Flow MRI were rated as excellent and good to excellent, respectively, and the studies utilized several different MRI data sampling strategies. By applying spiral sampling with compressed sensing to 4D Flow MRI, the blood flow of several abdominal veins could be imaged simultaneously in 18–25 s, without a significant loss of visual quality. Four-Dimensional Flow MRI might be a useful alternative to Doppler sonography for the diagnosis of cirrhosis and portal hypertension. Further clinical studies need to establish consensus regarding MRI sampling strategies in patients and healthy subjects.

Tracking plays an important role in super-resolution (SR) ultrasound imaging, as it improves the quality and sharpness of the final SR images. Moreover, tracking enables quantification of clinically important parameters, such as blood flow velocity. However, the tracking performance degrades in the presence of complex particle patterns and localization uncertainty due to noise and motion. This work presents and discusses multiple approaches for tracking evaluation and compares a nearest-neighbor (NN) with a Kalman tracker through simulations and an in vivo experiment. It is shown that in the presence of a localization uncertainty with a standard deviation (SD) of ?/5, the bias and SD of the velocity estimates reach -1.04 ± 0.9 mm/s and -0.12 ± 0.72 mm/s in the NN and Kalman tracker, respectively (relative to the peak velocity of 10 mm/s). The precision of individual track positions is estimated for an in vivo experiment as 37.95 ± 21.37 µm and 23.9 ± 11.82 µm for the NN and Kalman trackers, respectively. The results indicate that the Kalman tracker achieves a better velocity estimation and reduces localization uncertainty.

Background: Provoked gluteal claudication is a known risk after endovascular aortic repair (EVAR). Lowered gluteal muscle oxygenation (SgmO2) may be demonstrated by near-infrared spectroscopy (NIRS).Purpose: To evaluate NIRS-determined SgmO2 in EVAR patients.Material and Methods: NIRS-determined SgmO2 was used in an observational study design (n = 17). From the ambulatory setting, seven EVAR patients were included with reported gluteal claudication from medical records. In 10 patients scheduled for EVAR, SgmO2 was measured before and after the procedure. NIRS sensors were applied bilaterally on the gluteal region. Treadmill walking (12% incline, 2.4 km/h) was introduced to stress gluteal muscles.Results: A reduced SgmO2 with regional side difference (P < 0.05) was noted in all 10 patients following EVAR and four reported gluteal claudication. In patients with gluteal claudication (n = 7), treadmill decreased SgmO2. The time to recover the SgmO2 was prolonged for tissue exposed to occluded hypogastric artery (median = 512 s, range = 73-1207 s vs. median = 137, range = 0-643 s; P = 0.046).Conclusions: EVAR affects gluteal muscle oxygenation. NIRS could be used to assess whether gluteal claudication is related to lowered SgmO2.

BACKGROUND: Early detection of breast cancer (BC) is crucial in lowering the mortality.PURPOSE: To present an overview of studies concerning computer-aided detection (CAD) in screening mammography for early detection of BC and compare diagnostic accuracy and recall rates (RR) of single reading (SR) with SR + CAD and double reading (DR) with SR + CAD.MATERIAL AND METHODS: PRISMA guidelines were used as a review protocol. Articles on clinical trials concerning CAD for detection of BC in a screening population were included. The literature search resulted in 1522 records. A total of 1491 records were excluded by abstract and 18 were excluded by full text reading. A total of 13 articles were included.RESULTS: All but two studies from the SR vs. SR + CAD group showed an increased sensitivity and/or cancer detection rate (CDR) when adding CAD. The DR vs. SR + CAD group showed no significant differences in sensitivity and CDR. Adding CAD to SR increased the RR and decreased the specificity in all but one study. For the DR vs. SR + CAD group only one study reported a significant difference in RR.CONCLUSION: All but two studies showed an increase in RR, sensitivity and CDR when adding CAD to SR. Compared to DR no statistically significant differences in sensitivity or CDR were reported. Additional studies based on organized population-based screening programs, with longer follow-up time, high-volume readers, and digital mammography are needed to evaluate the efficacy of CAD.

BACKGROUND: This study aimed to develop a test with validity evidence for abdominal diagnostic ultrasound with a pass/fail-standard to facilitate mastery learning.METHOD: The simulator had 150 real-life patient abdominal scans of which 15 cases with 44 findings were selected, representing level 1 from The European Federation of Societies for Ultrasound in Medicine and Biology. Four groups of experience levels were constructed: Novices (medical students), trainees (first-year radiology residents), intermediates (third- to fourth-year radiology residents) and advanced (physicians with ultrasound fellowship). Participants were tested in a standardized setup and scored by two blinded reviewers prior to an item analysis.RESULTS: The item analysis excluded 14 diagnoses. Both internal consistency (Cronbach's alpha 0.96) and inter-rater reliability (0.99) were good and there were statistically significant differences (p < 0.001) between all four groups, except the intermediate and advanced groups (p = 1.0). There was a statistically significant correlation between experience and test scores (Pearson's r = 0.82, p < 0.001). The pass/fail-standard failed all novices (no false positives) and passed all advanced (no false negatives). All intermediate participants and six out of 14 trainees passed.CONCLUSION: We developed a test for diagnostic abdominal ultrasound with solid validity evidence and a pass/fail-standard without any false-positive or false-negative scores.KEY POINTS: • Ultrasound training can benefit from competency-based education based on reliable tests. • This simulation-based test can differentiate between competency levels of ultrasound examiners. • This test is suitable for competency-based education, e.g. mastery learning. • We provide a pass/fail standard without false-negative or false-positive scores.

Ultrasound-guided fine-needle aspiration cytology (US-FNAC) is used to evaluate the involvement of lymph nodes in various malignant diseases. Its value in detecting sentinel lymph node (SN) metastasis preoperatively in melanoma patients is controversial and is the subject of this study. In this prospective validation study, 91 consecutive patients with melanoma clinical stage I (n=64) and II (n=27) were examined with US-FNAC before SN biopsy from 2012 to 2014 at a tertiary center. All patients underwent lymphoscintigraphy before the US-FNAC. Lymph nodes that showed any of the Berlin morphologic criteria on ultrasonography were examined using FNAC. The median Breslow thickness of the melanomas was 1.22 mm (range: 0.47-11.5 mm). Twenty-two percent of the patients had metastases in their SNs, 90% of which were smaller than 2 mm in largest diameter. The percentages of metastases with a size more than 1 mm were 50 and 29%, respectively, in the true-positive and false-negative US groups. The sensitivity, specificity, positive predictive value, and negative predictive value for overall US examination were 30, 81, 24, and 83%, respectively. None of the FNACs contained conclusive malignant cells. The specificity of the FNAC was 76%. Our results show that US-FNAC was not a useful diagnostic tool in our setting as it did not add significantly to the staging and management of patients with mainly thin cutaneous melanomas, perhaps because of the often small size of the SN metastases. It may be useful in the early diagnosis of lymph node metastases in a subgroup of melanoma patients with larger metastases.

To obtain accurate blood flow velocity estimates it is important to remove the clutter signal originating from tissue. Conventionally, the clutter signal has been separated from the blood signal based on the difference of their spectral frequencies. However, this approach is not enough for obtaining vector flow measurements, since the spectra overlaps at high beam-to-flow angles. In this work a distinct approach is proposed, where the energy of the velocity spectrum is used to differentiate among the two signals. The energy based method is applied by limiting the amplitude of the velocity spectrum function to a predetermined threshold. The effect of the clutter filtering is evaluated on a plane wave (PW) scan sequence in combination with transverse oscillation (TO) and directional beamforming (DB) for velocity estimation. The performance of the filter is assessed by comparison of the velocity estimates of the proposed filter against a conventional moving average clutter filter. The effect of tissue motion is investigated using a Field II simulation of a straight vessel with moving wall, while the direct effect of the filter on the velocity estimates is evaluated on a CFD model of a carotid bifurcation with a fixed vessel wall. The results show that the proposed filter outperformed the moving average during moving vessel wall conditions, where standard deviations from the velocity magnitudes and angles were kept consistently below 6% and 6° compared to 63% and 48° on the moving average filter. The results on the CFD showed that on non-moving conditions the velocity estimates had minor statistical differences with errors on the magnitude of -7.95±10.1% and angles of 0.15±6.65° for the proposed filter compared to -5.83±9.08% and -0.12±4.48°.

The aim of this systematic review is to provide an overview of the use of Dynamic Contrast-enhanced Computed Tomography (DCE-CT) in patients with pancreatic cancer. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in PubMed, Cochrane Library, EMBASE, and Web of Science databases to identify all relevant publications. The QUADAS-2 tool was implemented to assess the risk of bias and applicability concerns of each included study. The initial literature search yielded 483 publications. Thirteen articles were included. Articles were categorized into three groups: nine articles concerning primary diagnosis or staging, one article about tumor response to treatment, and three articles regarding scan techniques. In exocrine pancreatic tumors, measurements of blood flow in eight studies and blood volume in seven studies were significantly lower in tumor tissue, compared with measurements in pancreatic tissue outside of tumor, or normal pancreatic tissue in control groups of healthy volunteers. The studies were heterogeneous in the number of patients enrolled and scan protocols. Perfusion parameters measured and analyzed by DCE-CT might be useful in the investigation of characteristic vascular patterns of exocrine pancreatic tumors. Further clinical studies are desired for investigating the potential of DCE-CT in pancreatic tumors.

The aim of this study was to provide an overview of the literature available on dynamic contrast-enhanced computed tomography (DCE-CT) as a tool to evaluate treatment response in patients with lung cancer. This systematic review was compiled according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only original research articles concerning treatment response in patients with lung cancer assessed with DCE-CT were included. To assess the validity of each study we implemented Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). The initial search yielded 651 publications, and 16 articles were included in this study. The articles were divided into groups of treatment. In studies where patients were treated with systemic chemotherapy with or without anti-angiogenic drugs, four out of the seven studies found a significant decrease in permeability after treatment. Four out of five studies that measured blood flow post anti-angiogenic treatments found that blood flow was significantly decreased. DCE-CT may be a useful tool in assessing treatment response in patients with lung cancer. It seems that particularly permeability and blood flow are important perfusion values for predicting treatment outcome. However, the heterogeneity in scan protocols, scan parameters, and time between scans makes it difficult to compare the included studies.

BACKGROUND: Vascular access complications after coronary angiography (CAG) and percutaneous coronary intervention (PCI) are known to increase morbidity, prolong hospitalization and raise hospital costs. Therefore, risk factor identification and improvement of safety strategies for vascular management are important. We aimed to assess the incidence of major vascular complications related to femoral access, and to identify potential risk factors.METHODS: Over a period of six years, 23,870 index procedures (CAG) were performed in two centres, prospectively entered in the database and retrospectively analysed. Data was obtained from the Eastern Danish Heart Registry and cross-matched with data from the Danish Vascular Registry. Index procedures were defined as the first trans-femoral procedure. Demographic, procedural and mortality data, as well as information on access complications requiring surgery within 30 days were collected. Mortality data were collected for minimum 12 months.RESULTS: We identified 130 (0.54%) access complications requiring surgery; 65 pseudoaneurysms (0.28%), 46 arterial occlusions (0.19%), 15 hematomas (nine groin and six retroperitoneal hematomas) (0.06%), and 4 arterial dissections (0.02%). Risk factors for complications were left sided femoral access (OR 4.11 [2.29-7.37] p<0.001), peripheral arterial disease (PAD) (OR 2.42 [1.48-3.94] p<0.0001) and female sex (OR 2.22 [1.51-3.24] p<0.0001).CONCLUSION: Vascular complications related to femoral access in coronary diagnostic and interventional procedures are low (0.54%). Risk factors were left sided access, PAD, and female sex.

The aim of this study was prospectively to monitor the volume flow in patients with arteriovenous fistula (AVF) with the angle independent ultrasound technique Vector Flow Imaging (VFI). Volume flow values were compared with Ultrasound dilution technique (UDT). Hemodialysis patients need a well-functioning vascular access with as few complications as possible and preferred vascular access is an AVF. Dysfunction due to stenosis is a common complication, and regular monitoring of volume flow is recommended to preserve AVF patency. UDT is considered the gold standard for volume flow surveillance, but VFI has proven to be more precise, when performing single repeated instantaneous measurements. Three patients with AVF were monitored with UDT and VFI monthly for five months. A commercial ultrasound scanner with a 9 MHz linear array transducer with integrated VFI was used to obtain data. UDT values were obtained with Transonic HD03 Flow-QC Hemodialysis Monitor. Three independent measurements at each scan session were obtained with UDT and VFI each month. Average deviation of volume flow between UDT and VFI was 25.7 % (Cl: 16.7% to 34.7%) (p= 0.73). The standard deviation for all patients, calculated from the mean variance of each individual scan sessions, was 199.8 ml/min for UDT and 47.6 ml/min for VFI (p = 0.002). VFI volume flow values were not significantly different from the corresponding estimates obtained using UDT, and VFI measurements were more precise than UDT. The study indicates that VFI can be used for surveillance of volume flow.

This work presents the development and first results of in vivo transthoracic cardiac imaging using an implementation of Vector Flow Imaging (VFI) via the Transverse Oscillation (TO) method on a phased-array transducer. Optimal selection of the lateral wavelength of the transversely-oscillating receive field is described, and results from Field II simulations are presented. Measurements are made using the SARUS experimental ultrasound scanner driving an intercostal phased-array probe. The acquisition sequence was composed of interleaved frames of 68-line B-mode and 17-direction, 32-shot vector velocity flow images. A flow pump was programmed for constant flow for in vitro acquisitions at varying depths in a tissue-mimicking fluid. Additionally, mitral, aortic, and tricuspid valves of two healthy volunteers were scanned from intercostal acoustic windows. The acquired RF data were beam-formed via the TO method, and fourth-order estimators were employed for the velocity estimation. The resulting images were compared with those from conventional spectral Doppler and color flow mapping sequences. VFI is shown to be a clinically-feasible tool, which enables new flexibility for choosing acoustic windows, visualizing turbulent flow patterns, and measuring velocities.