Frank J. P. Beeres

Early magnetic resonance imaging compared with bone scintigraphy in suspected scaphoid fractures

We evaluated 100 consecutive patients with a suspected scaphoid fracture but without evidence of a fracture on plain radiographs using MRI within 24 hours of injury, and bone scintigraphy three to five days after injury. The reference standard for a true radiologically-occult scaphoid fracture was either a diagnosis of fracture on both MRI and bone scintigraphy, or, in the case of discrepancy, clinical and/or radiological evidence of a fracture. MRI revealed 16 scaphoid and 24 other fractures. Bone scintigraphy showed 28 scaphoid and 40 other fractures. According to the reference standard there were 20 scaphoid fractures. MRI was falsely negative for scaphoid fracture in four patients and bone scintigraphy falsely positive in eight. MRI had a sensitivity of 80% and a specificity of 100%. Bone scintigraphy had a sensitivity of 100% and a specificity of 90%. This study did not confirm that early, short-sequence MRI was superior to bone scintigraphy for the diagnosis of a suspected scaphoid fracture. Bone scintigraphy remains a highly sensitive and reasonably specific investigation for the diagnosis of an occult scaphoid fracture.

Current methods of diagnosis and treatment of scaphoid fractures

Fractures of the scaphoid bone mainly occur in young adults and constitute 2-7% of all fractures. The specific blood supply in combination with the demanding functional requirements can easily lead to disturbed fracture healing. Displaced scaphoid fractures are seen on radiographs. The diagnostic strategy of suspected scaphoid fractures, however, is surrounded by controversy. Bone scintigraphy, magnetic resonance imaging and computed tomography have their shortcomings. Early treatment leads to a better outcome. Scaphoid fractures can be treated conservatively and operatively. Proximal scaphoid fractures and displaced scaphoid fractures have a worse outcome and might be better off with an open or closed reduction and internal fixation. The incidence of scaphoid non-unions has been reported to be between 5 and 15%. Non-unions are mostly treated operatively by restoring the anatomy to avoid degenerative wrist arthritis.

Early computed tomography compared with bone scintigraphy in suspected scaphoid fractures

Purpose: This study examined whether multidetector computed tomography (CT) is superior to bone scintigraphy for diagnosis of an occult scaphoid fracture. Methods and Materials: In a study period of 22 months, 100 consecutive patients with a clinically suspected scaphoid fracture and no fracture on scaphoid radiographs, were evaluated with CT within 24 hours after injury and bone scintigraphy between 3 and 5 days after injury. The reference standard for a true (radiographic occult) scaphoid fracture was either (1) diagnosis of fracture on both CT and bone scintigraphy or (2) in case of discrepancy, clinical and/or radiographic evidence of a fracture during follow-up. Results: CT showed 10 scaphoid and 18 other fractures. Bone scintigraphy showed 21 scaphoid and 36 other fractures. According to the reference standard, there were 14 scaphoid fractures. CT had a sensitivity of 64%, specificity of 99%, accuracy of 94%, a positive predictive value of 90%, and a negative predictive value of 94%. Bone scintigraphy had a sensitivity of 93%, specificity of 91%, accuracy of 91%, a positive predictive value of 62%, and a negative predictive value of 99%. Conclusion: This study could not confirm that early CT imaging is superior to bone scintigraphy for suspected scaphoid fractures.

Clinical prediction rule for suspected scaphoid fractures: A prospective cohort study.

BACKGROUNDnThe low prevalence of true fractures amongst suspected fractures magnifies the shortcomings of the diagnostic tests used to triage suspected scaphoid fractures.nnnPURPOSEnThe objective was to develop a clinical prediction rule that would yield a subset of patients who were more likely to have a scaphoid fracture than others who lacked the subset criteria.nnnMETHODSnSeventy-eight consecutive patients diagnosed with a suspected scaphoid fracture were included. Standardised patient history, physical examination, range of motion (ROM) and strength measurements were studied. The reference standard for a true fracture was based on the results of magnetic resonance imaging, bone scintigraphy, follow-up radiographs and examination.nnnRESULTSnAnalysis revealed three significant independent predictors: extension <50%, supination strength ≤ 10% and the presence of a previous fracture.nnnCONCLUSIONnClinical prediction rules have the potential to increase the prevalence of true fractures amongst patients with suspected scaphoid fractures, which can increase the diagnostic performance characteristics of radiological diagnostic tests used for triage.

MRI as a reference standard for suspected scaphoid fractures

OBJECTIVESnSome have suggested that MRI might be the best reference standard for a true fracture among patients with suspected scaphoid fractures. The primary aim of this study was to determine the rate of false-positive diagnosis of an acute scaphoid fracture in a cohort of healthy volunteers.nnnMETHODSnIn a prospective study, 33 healthy volunteers were recruited and both wrists of each were scanned, except for 2 volunteers for whom only one wrist was scanned. To simulate the usual clinical context the 64 scans of healthy volunteers were mixed with 60 MRI scans of clinically suspected scaphoid fractures but normal scaphoid radiographs. These 124 MRI scans were blinded and randomly ordered. Five radiologists evaluated the MRI scans independently for the presence or absence of a scaphoid fracture and other injuries according to a standard protocol.nnnRESULTSnTo answer the primary question, only the diagnoses from the 64 scans of healthy volunteers were used. The radiologists diagnosed a total of 13 scaphoid fractures; therefore, specificity for diagnosis of scaphoid fracture was 96% (95% confidence interval: range 94-98%). The 5 observers had a moderate interobserver agreement regarding diagnosis of scaphoid fracture in healthy volunteers (multirater κ=0.44; p<0.001).nnnCONCLUSIONSnThe specificity of MRI for scaphoid fractures is high (96%), but false-positives do occur. Radiologists have only moderate agreement when interpreting MRI scans from healthy volunteers. MRI is not an adequate reference standard for true fractures among patients with suspected scaphoid fractures.

Non-operative treatment of non-displaced scaphoid fractures may be preferred.

AIMnTo evaluate the outcome of non-displaced scaphoid fractures treated with 6 weeks of cast immobilisation, and to establish whether the benefits of non-operative treatment might outweigh those of early operation.nnnMETHODSnA retrospective study analysed 89 consecutive cases of scaphoid fracture treated at our institution between 2004 and 2007. Diagnosis and treatment methods and complication rates were evaluated.nnnRESULTSnAmong 71 non-displaced scaphoid fractures, >80% showed clinical consolidation after 6 weeks of cast immobilisation, and the remaining cases after 8-12 weeks. Two cases needed a longer period of cast immobilisation.nnnCONCLUSIONnA restricted period of cast immobilisation is usually adequate for the treatment of non-displaced scaphoid fractures.

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 &kgr; 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 MRI, CT and bone scintigraphy for suspected scaphoid fractures

PurposeThe best diagnostic modality for confirmation of the diagnosis of a scaphoid fracture that is not visible on the initial radiograph (occult scaphoid fracture) is still subject of debate. The aim of this study was to compare the accuracy of magnetic resonance imaging (MRI), computed tomography (CT) and bone scintigraphy (BS) for the diagnosis of these occult scaphoid fractures.Patients and methodsIn a study period of 12xa0months, 33 consecutive patients with a clinically suspected scaphoid fracture without a fracture on the scaphoid radiographs were evaluated with MRI, CT and BS. In case of a discrepancy between the diagnostic modalities, the final diagnosis was based on standardised follow-up with clinical examination and a repeated radiograph.ResultsThree of the 33 patients had a scaphoid fracture. MRI missed one scaphoid fracture and did not over-diagnose. CT missed two scaphoid fractures and did not over-diagnose. BS missed no scaphoid fractures and over-diagnosed one scaphoid fracture in a patient with a fracture of the trapezium.ConclusionThis study shows that neither MRI, nor CT and BS are 100xa0% accurate in diagnosing occult scaphoid fractures. MRI and CT miss fractures, and BS tends to over-diagnose. The specific advantages and limitations of each diagnostic modality should be familiar to the treating physicians and taken into consideration during the diagnostic process.

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.

Initial experience of SPECT/CT in the diagnosis of occult scaphoid fracture

Background *Equal contributors. Planar bone scintigraphy (PBS) is often advocated for diagnosing occult scaphoid fractures. PBS is a sensitive diagnostic modality, but lacks specificity, which may result in over-diagnosis. Purpose To examine, in a pilot study, the potential additional value of single photon emission computed tomography (SPECT) combined with low dose computed tomography (CT) for the diagnosis of an occult scaphoid fracture. Material and Methods Ten patients that underwent combined PBS and SPECT/CT for a clinically suspected scaphoid fracture, where radiographs could not detect a fracture, were included in this pilot study. The PBS and SPECT/CT results were independently and separately evaluated by a nuclear physician for scaphoid fractures and other injuries. Results PBS was positive for a scaphoid fracture in four patients and diagnosed three other fractures. SPECT/CT showed five scaphoid fractures and one other fracture. SPECT/CT – PBS had discrepant results in three patients. In two patients PBS diagnosed a trapezoid fracture where SPECT/CT showed a scaphoid fracture. The other patient was diagnosed with a scaphoid fracture on PBS, whereas SPECT/CT showed bone bruise of other carpal bones. Conclusion SPECT/CT has the potential to be more accurate than PBS as it uses anatomical information of the CT to discriminate between the scaphoid, other carpal bones, and bone bruises. Larger studies with an independent reference standard are needed for confirmation of these preliminary data.