Image Size Influences Visual Search and Perception of Hemorrhages When Reading Cranial CT: An Eye-Tracking Study.

OBJECTIVE: The aim of this study was to explore reader gaze, performance, and preference during interpretation of cranial computed tomography (cCT) in stack mode at two different sizes. BACKGROUND: Digital display of medical images allows for the manipulation of many imaging factors, like image size, by the radiologists, yet it is often not known what display parameters better suit human perception. METHOD: Twenty-one radiologists provided informed consent to be eye tracked while reading 20 cCT cases. Half of these cases were presented at a size of 14 × 14 cm (512 × 512 pixels), half at 28 × 28 cm (1,024 × 1,024 pixels). Visual search, performance, and preference for the two image sizes were assessed. RESULTS: When reading small images, significantly fewer, but longer, fixations were observed, and these fixations covered significantly more slices. Time to first fixation of true positive findings was faster in small images, but dwell time on true findings was longer. Readers made more false positive decisions in small images, but no overall difference in either jackknife alternative free-response receiver operating characteristic or reading time was found. CONCLUSION: Overall performance is not affected by image size. However, small-stack-mode cCT images may better support the use of motion perception and acquiring an overview, whereas large-stack-mode cCT images seem better suited for detailed analyses. APPLICATION: Subjective and eye-tracking data suggest that image size influences how images are searched and that different search strategies might be beneficial under different circumstances.

Low-grade (WHO II) and anaplastic (WHO III) gliomas: differences in morphology and MRI signal intensities.

OBJECTIVE: To evaluate the diagnostic potential of a multi-factor analysis of morphometric parameters and signal characteristics of brain tumours and peritumoural areas for distinguishing WHO-grade II and III gliomas at magnetic resonance imaging (MRI). METHODS: MR examinations of 108 patients with histologically proven World Health Organization (WHO) grade II and III gliomas were included. Morphological criteria and MR signal characteristics were evaluated. The data were subjected to a multifactorial logistic regression analysis to differentiate between grade II and grade III gliomas. The discriminatory power was assessed by receiver operating characteristic (ROC). RESULTS: Logistic regression analysis showed that WHO grade II and III can be distinguished based on contrast enhancement, cortical involvement, margin of the enhancing lesion and maximum diameter (width and length) of the peritumoural area (the so-called tumour infiltration zone). With the final model of logistic regression analysis and with the cut-off value ≥ 0.377, WHO grade III glioma is predicted with a sensitivity of 71.0 % and a specificity of 80.4 %. CONCLUSION: Measurement of maximum diameter of peritumoural area, contrast enhancement as well as cortical involvement and the margin of the contrast-enhancing lesion can be used easily in clinical routine to adequately distinguish WHO grade II from grade III gliomas. KEY POINTS: • MRI offers new information concerning WHO-grade II and III gliomas. • The differentiation between such tumour grades is important for therapeutic decisions. • We assessed differences in enhancement, cortical involvement, margins and peritumoural appearances. • WHO grade III gliomas can be predicted with reasonable sensitivity and specificity.

The FRISK (Fracture Risk)-A New Tool to Indicate the Probability of Fractures.

Increasing patient inflow into the emergency department makes it necessary to optimize triage management. The scope of this work was to determine simple factors that could detect fractures in patients without the need for specialized personnel. Between 2014 and 2015, 798 patients were admitted to an orthopedic emergency department and prospectively included in the study. The patients received a questionnaire before contacting the doctor. Objective and subjective data were evaluated to determine fracture risk for the upper and lower extremities. The highest risk for fractures in one region was the hip (73.21%; n = 56), followed by the wrist (60.32%; n = 63) and the femoral shaft (4 of 7, 57.14%; n = 7). The regions with the lowest risk were the knee (8.41%; n = 107), the ankle (18.29%; n = 164), and the forearm shaft (30.00%; n = 10). Age was a predictor for fracture: patients older than 59 years had a risk greater than 59.26%, and patients older than 90 years had a risk greater than 83.33%. The functional questions could exclude fractures. Three factors seem to be able to predict fracture risk: the injured region, the patient's age, and a functional question. They can be used for a probatory heuristic that needs to be proven in a prospective way.

Diagnosing fractures: pain intensity and subjective functional impairment are unreliable markers for initial assessment of possible extremity fractures.

OBJECTIVES: The triage of trauma patients is based on patient-given information. The aim of the study was the accuracy of pain intensity, subjective functional impairment, trauma history, and clinical examination in identifying patients with fractures. METHODS: We prospectively asked 436 patients with an extremity trauma whether they believed they had a fracture. Pain intensity and subjective functional impairment were also assessed. The physicians were also asked, based on trauma history and clinical examination. RESULTS: The sensitivity and specificity of patient opinion and of the functional questions for fracture detection were low. The combination of history and clinical examination delivered the best results. There was only a slight difference in pain intensity between patients with and those without fractures. CONCLUSION: Fracture diagnosis based only on patient opinion or subjective functional impairment can be misleading. Pain intensity needs further investigation for its role in fracture detection.

Does preference influence performance when reading different sizes of cranial computed tomography?

Radiology practice is based on the implicit assumption that the preference for a particular presentation mode goes hand in hand with superior performance. The present experiment tests this assumption in what pertains to image size. Forty-three radiologists were asked to identify intracranial hemorrhages on 20 cranial computed tomography scans in two image sizes, [Formula: see text] and [Formula: see text]. They were asked to indicate which size they preferred and subsequently rated each size on a continuous scale in terms of how much they liked them. The results show no correlation between the jackknife free-response receiver operating characteristic figure of merit and preference rated on a continuous scale (large image: [Formula: see text], [Formula: see text]; small images: [Formula: see text], [Formula: see text]). Similarly, there was no significant correlation between the time a radiologist took to read a case and preference rated on the continuous scale (large image: [Formula: see text], [Formula: see text]; small images: [Formula: see text], [Formula: see text]). When dividing radiologists into two groups according to their size preference, there was no significant difference in performance between groups with regard to either large or small images. The results suggest that the preference for an image size and performance with regard to it are not related.

Quantitative imaging of the tissue contrast agent [Gd(DTPA)]²â» in articular cartilage by laser ablation inductively coupled plasma mass spectrometry.

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is an emerging analytical technique in the generation of quantitative images of MR contrast agent distribution in thin tissue sections of articular cartilage. An analytical protocol is described that includes sample preparation by cryo-cutting of tissue sections, mass spectrometric measurements by LA-ICP-MS and quantification of gadolinium images by one-point calibration, standard addition method (employing matrix-matched laboratory standards) and isotope dilution analysis using highly enriched stable Gd-155 isotope (abundance 92 vs 14.8% in the [Gd(DTPA)]²â» contrast agent). The tissue contrast agent concentrations of [Gd(DTPA)]²â» in cartilage measured in this work are in agreement with findings obtained by magnetic resonance imaging and other analytical methodologies. The LA-ICP-MS imaging data also confirm the observation that the spatial distribution of [Gd(DTPA)]²â» in the near-equilibrium state is highly inhomogeneous across cartilage thickness with the highest concentration measured in superficial cartilage and a strong decrease toward the subchondral bone. In the present work, it is shown for the first time that LA-ICP-MS can be applied to validate the results from quantitative gadolinium-enhanced MRI technique of articular cartilage.

CT guided bone biopsy using a battery powered intraosseous device.

PURPOSE: To evaluate the feasibility of a battery powered intraosseous device to perform CT-fluoroscopy guided bone biopsy. METHODS: Retrospective analysis of 12 patients in whom bone specimen were acquired from different locations under CT-fluoroscopy guidance using the OnControl bone marrow biopsy system (OBM, Vidacare, Shavano Park, TX, USA). Data of the 12 were compared to a historic cohort in whom the specimen were acquired using the classic Jamshidi Needle, as reference needle using manual force for biopsy. RESULTS: Technical success was reached in 11 of 12 cases, indicated by central localisation of the needle within the target lesion. All specimen sampled were sufficient for histopathological workup. Compared to the historical cohort the time needed for biopsy decreased significantly from 13 ± 6 to 6 ± 4 min (P = 0.0001). Due to the shortened intervention time the radiation dose (CTDI) during CT-fluoroscopy was lowered significantly from 169 ± 87 to 111 ± 54 mGy × cm (P = 0.0001). Interventional radiologists were confident with the performance of the needle especially when using in sclerotic or osteoblastic lesions. CONCLUSION: The OBM is an attractive support for CT-fluoroscopy guided bone biopsy which is safe tool and compared to the classical approach using the Jamshidi needle leading to significantly reduced intervention time and radiation exposure.

Arthroscopic single-row modified mason-allen repair versus double-row suture bridge reconstruction for supraspinatus tendon tears: a matched-pair analysis.

BACKGROUND: Arthroscopic double-row fixation of supraspinatus tendon tears compared with single-row techniques is still a matter of debate. HYPOTHESIS: Arthroscopic double-row rotator cuff repair using the suture bridge technique provides better clinical results and lower retear rates than does single-row repair using a modified Mason-Allen stitch technique. STUDY DESIGN: Cohort study; Level of evidence 3. METHODS: Forty patients underwent either an arthroscopic single-row modified Mason-Allen stitch (SR) (n = 20; mean age ± SD, 61.5 ± 7.4 y) or a modified suture bridge double-row repair (DR) (n = 20; age, 61.2 ± 7.5 y). The anteroposterior extension was classified as Bateman I in 10% and Bateman II in 90% of patients in the SR group and as Bateman II in 80% and Bateman III in 20% of patients in the DR group. Patients were matched for sex and age. The subjective shoulder value (SSV), Constant-Murley score (CS), and Western Ontario Rotator Cuff Index (WORC) were used for clinical follow-up. Furthermore, MRI scans were conducted for analysis of tendon integrity, muscle atrophy, and fatty infiltration via semiquantitative signal intensity analysis. In addition, re-defect patterns were evaluated. RESULTS: The mean follow-up time in the SR group was 16.8 ± 4.6 months. The mean SSV was 91.0% ± 8.8%, mean CS was 82.2 ± 8.1 (contralateral side, 88.8 ± 5.3), and mean WORC score was 96.5% ± 3.2%. The mean follow-up time in the DR group was 23.4 ± 2.9 months, with patients achieving scores of 92.9% ± 9.6% for the SSV, 77.0 ± 8.6 for the CS (contralateral side, 76.7 ± 17.1), and 90.7% ± 12.6% for the WORC (P > .05). No significant differences were detected in the clinical outcome between groups. Tendon integrity was as follows. Type 1, none in either group; type 2, 4 SR and 5 DR; type 3, 9 SR and 10 DR; type 4, 3 SR and 3 DR; and type 5, 3 SR and 2 DR. The failure rate was 31.6% (n = 6) in the SR group and 25% (n = 5) in the DR group (P > .05). No significant differences were obtained for muscular atrophy or fatty degeneration (SR group, 0.94 ± 0.16; DR group, 1.15 ± 0.5) (P > .05). Re-defects revealed lateral cuff failure in 83.3% of SR patients in contrast to patients treated with DR techniques. The re-defect pattern was medial cuff failure in 80% of the patients. CONCLUSION: The clinical results after modified Mason-Allen single-row versus double-mattress suture bridge technique did not demonstrate significant differences in a matched patient cohort. Concerning the failure mode, single- and double-row techniques seem to demonstrate different re-defect patterns.