Observer variation in MRI for suspected scaphoid fractures

The aim of this study was to evaluate prospectively the observer variation in the detection of pathology on MRI for suspected acute scaphoid fracture. 79 consecutive MR scans were included to calculate the inter-observer variation. All patients were suspected of having a scaphoid fracture but had no fracture on radiographs. 38 randomly chosen MR scans were used to calculate the intra-observer variation. Four observers, with varying levels of expertise, blinded scored three items: (i) scaphoid fracture, (ii) localization of a scaphoid fracture, and (iii) another fracture. The observer variation was analysed using the kappa statistic. The inter-observer variation for a scaphoid fracture showed substantial agreement. For the localization of a scaphoid fracture and another fracture, there was a moderate and substantial agreement, respectively. The intra-observer variation for a scaphoid fracture had an almost perfect agreement. For the localization of a scaphoid fracture and another fracture, there was an almost perfect and substantial agreement, respectively. In conclusion, the observer variation in MRI of suspected scaphoid fractures was low. The influence of expertise with MRI in daily practice should be taken into consideration. Observers with little experience of MRI will identify all scaphoid fractures but are likely to over-diagnose injuries. Based on these results, it is recommended that all scans are reviewed by an experienced radiologist.     

Reliability of bone scintigraphy for suspected scaphoid fractures

PURPOSE: To examine the observer variation for bone scintigraphy in the detection of occult scaphoid fractures in daily practice, using only the early bone scanning images. METHODS: One hundred bone scans of patients with a suspected scaphoid fracture but negative initial radiographs were prospectively included to calculate the inter- and intraobserver variation. Three nuclear medicine physicians independently evaluated all bone scans at 2 different points in time with a 3-month interval. The observers filled out a blinded scoring sheet for each patient. They scored if a scaphoid fracture was present or not. In addition, they scored the presence or absence of another fracture. The inter- and intraobserver variation was analyzed using the kappa statistic. RESULTS: The interobserver variation showed substantial agreement for a scaphoid fracture and almost perfect agreement for another fracture. The intraobserver variation showed almost perfect agreement for both a scaphoid fracture and another fracture. CONCLUSIONS: In the present study, early static images of bone scintigraphy for suspected scaphoid fractures showed very little inter- and intraobserver variation. In addition, expertise does not seem to have a negative influence on the results. This enhances the possibility of using bone scintigraphy in daily practice.     

Comparison of conventional radiography and MDCT in suspected scaphoid fractures

AIM: To determine the diagnostic accuracy and radiation dose of conventional radiography and multidetector computed tomography(MDCT) in suspected scaphoid fractures.METHODS: One hundred twenty-four consecutive patients were enrolled in our study who had suffered from a wrist trauma and showed typical clinical symptoms suspicious of an acute scaphoid fracture. All patients had initially undergone conventional radiography. Subsequent MDCT was performed within 10 d because of persisting clinical symptoms. Using the MDCT data as the reference standard, a fourfold table was used to classify the test results. The effective dose and impaired energy were assessed in order to compare the radiation burden of the two techniques. The Wilcoxon test was performed to compare the two diagnostic modalities.RESULTS: Conventional radiography showed 34 acute fractures of the scaphoid in 124 patients(42.2%). Subsequent MDCT revealed a total of 42 scaphoid fractures. The sensitivity of conventional radiography for scaphoid fracture detection was 42.8% and its specificity was 80% resulting in an overall accuracy of 59.6%. Conventional radiography was significantly inferior to MDCT(P < 0.01) concerning scaphoidfracture detection. The mean effective dose of MDCT was 0.1 m Sv compared to 0.002 m Sv of conventional radiography.CONCLUSION: Conventional radiography is insufficient for accurate scaphoid fracture detection. Regarding the almost negligible effective dose, MDCT should serve as the first imaging modality in wrist trauma.     

Modified carpal box technique in the diagnosis of suspected scaphoid fractures

PURPOSE: To establish and test the clinical efficacy of a new diagnostic algorithm with the extensive utilization of modified carpal box radiography (mX-CB) in the detection of scaphoid fractures. MATERIAL AND METHODS: Initial and early follow-up radiographic evaluation of 146 suspected scaphoid fractures were carried out by mX-CB. Patients with unconfirmed diagnosis were referred to CT. Patients were followed for 1 year after injury. Sensitivity, specificity and interobserver agreement of reading mX-CB images were determined statistically. RESULTS: No non-union or avascular necrosis was seen at 1 year after the injury. 90% of the fractures were diagnosed by mX-CB, only 6.8% of the patients needed referral to CT. Sensitivity of mX-CB at initial presentation was 81.6%. Interobserver agreement was very high among evaluators of mX-CB images. CONCLUSION: Extensive utilization of mX-CB as primary and early follow-up investigation resulted in high initial diagnostic accuracy and low referral rate to a more expensive diagnostic modality.     

Magnetic resonance imaging of suspected scaphoid fractures using a low field dedicated extremity MR system

AIM: To determine whether magnetic resonance imaging (MRI) using a dedicated extremity system could be utilized for the routine assessment of patients with a clinically suspected scaphoid fracture, and to determine the most cost-effective timing of MRI for these patients. MATERIALS AND METHODS: MRI of the wrist using a 0.2T extremity MR system was performed in two groups of patients. Fifty-six patients were examined within 4 days of injury and 53 with persistent symptoms at 10 days to 6 weeks following injury. A scaphoid series of radiographs was negative in both groups. RESULTS: The early MR group had seven scaphoid, six radial and four other fractures. Management was altered in 89%. The late MR group had 14 scaphoid, nine radial and three other fractures. Management was altered in 69%. A cost model showed that overall costs are less with early rather than late scanning. CONCLUSION: MRI of the wrist when scaphoid fracture is suspected can be undertaken in all patients with negative radiographs and could be performed in most departments with an MRI machine. There are significant patient benefits and overall costs would change little from conventional practice.     

Diagnostic accuracy of multidetector computed tomography for patients with suspected scaphoid fractures and negative radiographic examinations

Purpose  

The aim of this prospective study was to evaluate the diagnostic accuracy of multidetector computed tomography (MDCT) in detecting occult scaphoid fractures.     

Technique for diagnosis of scaphoid fractures

Fracture of the scaphoid bone accounts for 60 percent of all carpal injuries. Early diagnosis of a scaphoid fracture is extremely important. Missing the fracture may lead to disability due to potential avascular necrosis or non-union of the fragments. The presence of a scaphoid fracture may be determined with greater certainty by using a multiple angle scaphoid series detailed by the author.     

Cost effectiveness of adding magnetic resonance imaging to the usual management of suspected scaphoid fractures

Objective: To determine the cost effectiveness of a magnetic resonance imaging scan (MRI) within 5 days of injury compared with the usual management of occult scaphoid fracture.     

The efficacy of plain films vs MRI in the detection of scaphoid fractures

An investigation was carried out to determine whether or not professionals perceived plain film radiography to be the ‘gold-standard’ in the detection of scaphoid fractures. Literature highlighted that plain film radiography was an unreliable method for detecting such fractures and that magnetic resonance imaging (MRI) should now be regarded as the new ‘gold-standard’.Using a quantitative method, a total of 100 postal questionnaires were sent out to radiologists in 20 different imaging departments throughout the United Kingdom (UK) asking them their opinion on this controversial subject. In addition, the investigation looked into the use of MRI within each department in trying to determine whether or not it was surpassing plain film radiography as an established practice for detecting scaphoid fractures.Of the 100 questionnaires that were sent out, a total of 45 were returned from a total of 13 different departments.The results of this investigation conclude that plain film radiography is still used as a primary imaging modality to detect scaphoid fractures in all departments. There was much support for the use of plain film radiography with the modality being praised time and time again for its ease, 24-h availability, low cost and reproducibility.MRI was acknowledged as being superior in its capability to detect scaphoid fractures in comparison to plain films; its current use, however, is limited owing to high costs, lack of availability and long waiting lists. It would appear from this study that MRI is regarded as a useful modality in cases whereby plain film radiography fails to detect the presence or absence of a fracture in clinically positive patients, with great future potential.     

Inter-reader agreement of the ESUR score for prostate MRI using in-bore MRI-guided biopsies as the reference standard

Objectives

The recent European Society of Urogenital Radiology (ESUR) guidelines for evaluation and reporting of prostate multiparametric magnetic resonance imaging (mp-MRI) include the Prostate Imaging Reporting and Data System (PI-RADS). The aim of this study was to investigate the inter-reader agreement of this scoring system.

Methods

One hundred and sixty-four lesions in 67 consecutive patients with elevated prostate-specific antigen and previously negative trans-rectal ultrasound (TRUS)-guided biopsy were scored retrospectively by three blinded readers using PI-RADS. Mp-MRI was performed at 3 T using T2-weighted, diffusion-weighted and dynamic contrast-enhanced imagings (T2WI, DWI, DCE-MRI). Histology of all lesions was obtained by in-bore MRI-guided biopsy. Cohen’s kappa statistics were calculated for all readers.

Results

Inter-reader agreement for all lesions was good to moderate (T2WI, κ?=?0.55; DWI, κ?=?0.64; DCE-MRI, κ?=?0.65). For tumour lesions it was good (T2WI, κ?=?0.66; DWI, κ?=?0.80; DCE-MRI, κ?=?0.63) and for benign lesions moderate to good (T2WI, κ?=?0.46; DWI, κ?=?0.52; DCE-MRI, κ?=?0.67). Using an overall PI-RADS score with a threshold of ≥10, we achieved a sensitivity of 85.7 %, and negative predictive value of 90.1 % for biopsied lesions.

Conclusion

PI-RADS score shows good to moderate inter-reader agreement and enables standardised evaluation of prostate mp-MRI, with high sensitivity and negative predictive value.

Key Points

? The European Society of Urogenital Radiology recently published guidelines for prostate MRI. ? We have evaluated inter-reader agreement of ESUR scoring for multiparametric prostate MRI. ? PI-RADS shows good to moderate inter-reader agreement and is clinically applicable. ? PI-RADS achieves in our series high sensitivity and negative predictive value for biopsied lesions. ? PI-RADS can be used as standardised scoring system in prostate cancer detection.     

Diagnostic performance of ultrasound in patients with suspected brachial plexus lesions in adults: a multicenter retrospective study with MRI, surgical findings and clinical follow-up as reference standard

Purpose

To evaluate brachial plexus ultrasound (US) performance in a large multicenter study.

Materials and methods

The research was approved by the Institutional Review Boards, and all patients gave written informed consent. A multicenter retrospective trial including three centers was performed between March, 2006 and April, 2011. A total of 204 patients who received a brachial plexus ultrasound requested by the referring physician were enrolled: magnetic resonance imaging, surgical findings and clinical follow-up of at least 12 months were used as the reference standard. Sensitivity, specificity with 95 % confidence intervals (CIs), positive predictive value (PPV), pre-test-probability (the prevalence), negative predictive value (NPV), pre- and post- test odds (OR), likelihood ratio for positive results (LH+), likelihood ratio for negative results (LH-), accuracy and post-test probability (post-P) were reported on a per-patient basis.

Results

The overall sensitivity and specificity with 95 % CIs were: 0.76 (0.75–0.97); 0.96 (0.77–0.89). Overall PPV, pre-test probability, NPV, pre-OR, post-OR, LH+, LH-, Accuracy and post-P were: 0.93/0.43/0.84/0.75/0.75/13.4/17.6/0.25/0.88/0.93, respectively.

Conclusions

The specificity of brachial plexus US in patients suspected of having a brachial plexus lesion is very high.     

US for detecting renal calculi with nonenhanced CT as a reference standard.

PURPOSE: To determine the sensitivity and specificity of ultrasonography (US) for detecting parenchymal and renal pelvis calculi and to establish the accuracy of US for determining the size and number of calculi. MATERIALS AND METHODS: A total of 123 US and computed tomographic (CT) examinations were compared retrospectively for the presence of renal calculi. The sensitivity of US was determined for individual calculi and at least one calculus per examination. Retrospective findings were compared with the original US interpretation. The sizes of calculi in longest axis were compared on US and CT images, and the US detection of calculi in the left and right kidneys was compared. The use of US for detecting the full extent of calculus burden was evaluated in patients with multiple calculi. RESULTS: US depicted 24 of 101 calculi identified at CT, yielding a sensitivity of 24% and a specificity of 90%. There was no substantial difference for the detection of calculi in the right and left kidneys. The sensitivity of US for any calculi in a patient was 44%, equal to that of the original US interpretation. US enabled identification of 39% of patients with multiple calculi and demonstrated all calculi in 17% of these patients. The mean size of calculi detected with US was 7.1 mm +/- 1.2 (95% CI); 73% of calculi not visualized at US were less than 3.0 mm in size. Calculus size based on US and CT measurements was concordant in 79% of cases and differed by a mean of 1.5 mm +/- 0.7. CONCLUSION: US is of limited value for detecting renal calculi.     

Diagnosis and treatment of scaphoid fractures

The scaphoid bone in the wrist is the most frequently fractured carpal bone. This Directed Reading discusses types of scaphoid fractures, issues of special concern (eg, the risk of avascular necrosis and delayed union or non-union), steps involved in bone fracture healing and various imaging modalities used for scaphoid fracture diagnosis. Types of fracture management such as casting and surgical intervention are examined. Factors that can negatively influence bone healing, such as certain disease processes and tobacco use, are also investigated. This article is a Directed Reading. Your access to Directed Reading quizzes for continuing education credit is determined by your area of interest. For access to other quizzes, go to www.asrt.org/store.     

MRI screening for silicone breast implant rupture: accuracy,inter- and intraobserver variability using explantation results as reference standard

Objectives

The recall of Poly Implant Prothèse (PIP) silicone breast implants in 2010 resulted in large numbers of asymptomatic women with implants who underwent magnetic resonance imaging (MRI) screening. This study’s aim was to assess the accuracy and interobserver variability of MRI screening in the detection of rupture and extracapsular silicone leakage.

Methods

A prospective study included 107 women with 214 PIP implants who underwent explantation preceded by MRI. In 2013, two radiologists blinded for previous MRI findings or outcome at surgery, independently re-evaluated all MRI examinations. A structured protocol described the MRI findings. The ex vivo findings served as reference standard.

Results

In 208 of the 214 explanted prostheses, radiologists agreed independently about the condition of the implants. In five of the six cases they disagreed (2.6 %), but subsequently reached consensus. A sensitivity of 93 %, specificity of 93 %, positive predictive value of 77 % and negative predictive value of 98 % was found. The interobserver agreement was excellent (kappa value of 0.92).

Conclusions

MRI has a high accuracy in diagnosing rupture in silicone breast implants. Considering the high kappa value of interobserver agreement, MRI appears to be a consistent diagnostic test. A simple, uniform classification, may improve communication between radiologist and plastic surgeon.

Key points

? MRI has a high accuracy in diagnosing rupture in silicone breast implants. ? MRI appears to be a consistent diagnostic test with excellent interobserver agreement. ? A simple, uniform classification system, improves communication between radiologist and plastic surgeon. ? The interobserver agreement on implant rupture is higher than on extracapsular leakage.     

CT of the wrist in suspected scaphoid fracture.

Bone scan and sagittal projection CT of the scaphoid was performed in 10 patients with clinically suspected scaphoid fractures. The primary and follow-up plain radiographs were negative or equivocal for fracture. CT examination demonstrated scaphoid fracture in 7 patients and normal findings in 3. It is concluded that CT of the scaphoid can replace bone scan to diagnose or rule out fracture in institutions where nuclear medicine facilities are not available.     

Computer-assisted three-dimensional reconstruction of the corticospinal system as a reference for CT and MRI

We present a three-dimensional (3D) anatomical computer-graphics model of the corticospinal system acquired from equidistant serial anatomical slices of six intracranially-fixed human brains. This model is part of a neuroanatomical reference system (NeuRef) which enables 3D visualization of the brain and shows the relationship of its components such as anatomical structures, functional fibre tracts and arteries. Sections through the models can be matched with corresponding CT or MR images. This allows the probable localisation of corticospinal fibres on CT or MRI. Received: 4 June 1997 Accepted: 27 February 1998     

Comparison of 1-h with 3-h planar 99mTc-pyrophosphate scintigraphy in patients with suspected transthyretin cardiac amyloidosis using SPECT as a reference standard

Annals of Nuclear Medicine - The purpose of this study was to examine the diagnostic value of planar 99mTc-pyrophosphate (PYP) imaging at 1 and 3&nbsp;h after tracer administration in patients...