Ville V. Haapamaki

Lisfranc Fracture-dislocation in Patients with Multiple Trauma: Diagnosis with Multidetector Computed Tomography

Background: We assessed acute phase multidetector computed tomography (MDCT) findings of Lisfranc fracture-dislocations in patients with multiple trauma referred to a Level I trauma center over a 29-month period. Methods: Two hundred and eighty two patients (208 male and 74 female) between the ages of 13 and 89 (mean 42) years had, at the request of emergency room physicians, MDCT of the foot and ankle after acute injury. Results: A total of 21 Lisfranc fracture-dislocations were found in 19 (7%) patients. Two main injury mechanisms were established: falling from high places in 10 injuries (48%) and traffic accidents in five (24%). Primary radiographs were available in 17 (81%) feet, and four (24%) had false negative radiographic results when compared to MDCT. In all Lisfranc fracture-dislocations MDCT showed the joint anatomy and the extent of dislocation better than primary radiographs, and in six (46%) of 13 true positive primary radiographs, MDCT revealed additional occult fractures in the Lisfranc joint. Multidetector CT revealed additional occult fractures in other parts of the foot and ankle in six (35%) of 17 feet. Conclusions: Standard radiography remains a primary diagnostic modality in acute foot and ankle trauma. Multidetector CT with high-quality multiplanar reconstruction (MPR) is recommended as a complementary examination in high-energy injury in patients with multiple trauma or in patients in whom radiographic images are equivocal. This may reveal Lisfranc fracture-dislocations, show the extent of the fracture-dislocation, and reveal occult fractures in other parts of the foot and ankle.

MR imaging of fatigue stress injuries to bones: intra- and interobserver agreement

The aim of this study was to determine the validity of MR imaging (MRI) in the assessment of stress-related injuries to bone.MR images of 50 military recruits (8 females and 42 males; 18-27 (mean 20) years of age) were retrospectively evaluated twice for stress injuries to bone by 4 radiologists (2 musculoskeletal radiologists, 2 radiology residents). Coronal T1-weighed (T1W) and STIR images, as well as axial and coronal T2-weighted (T2W) fat-suppressed images were taken using a 1.0T scanner. Rates for sensitivity, specificity, and accuracy of MRI of the stress-related injuries were calculated. Intraobserver and interobserver agreement was determined with kappa statistics. Rates for MRI sensitivity were 27-96%, for specificity 65-100%, and for diagnostic accuracy 58-97%. Lowest rates were seen when reading T1W images and highest when reading STIR images. Readers showed moderate to excellent intraobserver agreement (kappa 0.75-0.95). Interobserver agreement was fair to excellent (kappa 0.41-0.91), and the lowest values were seen in the interpretation of T1W images. Normal findings could be differentiated from various grades of stress injury to bone.MRI is a valid means of revealing the presence of stress injuries to bone and their staging. Observer agreement is good to excellent when using T2W images and STIR images, while T1W images are of lesser value.

Wrist injuries; diagnosis with multidetector CT

The aim of the study was to assess acute-phase multidetector CT (MDCT) findings in wrist injuries. We retrieved all emergency room MDCT requests processed in the period from August 2000 to May 2003. All patients with a wrist injury who underwent MDCT initially were included. Imaging studies were evaluated in relation to injury mechanism, fracture location, and fracture type. A total of 6422 MDCT examinations were performed during this 34-month period, and 38 patients (24 male, 14 female, age range 21–73 years, mean age 40 years) met the inclusion criteria. MDCT revealed 56 fractures and 7 dislocations in 29 patients. In 9 patients (24%) MDCT findings were normal. Eleven patients (29%) underwent surgical procedures. The main injury mechanism was a fall (58%). In 33 cases the primary radiograph was available. Compared to primary radiographs, MDCT revealed 9 occult fractures, mainly in small carpal bones. In 14 cases a suspected fracture (of the scaphoid in 7 cases) was ruled out by MDCT. Due to high-quality two-dimensional reformatting, MDCT examinations were not dependent on the wrist’s position in the CT gantry. In the comparison with radiography, MDCT detected occult fractures and ruled out suspected fractures, both mainly in the small carpal bones. High-quality two-dimensional reformats gave significant information about the fracture anatomy. MDCT provides fast and valuable information in assessing complex wrist fractures or when the primary radiograph is equivocal.

Multidetector Computed Tomography in Acute Joint Fractures

Conventional radiography plays an essential diagnostic role in the primary evaluation of acute joint trauma. In complex fractures, however, computed tomography (CT) is an imaging modality often used second to radiography. As a result of technical breakthroughs in the field, multidetector CT (MDCT) allows faster imaging and better temporal, spatial, and contrast resolution compared with conventional single-slice spiral CT. MDCT with multiplanar reformation is helpful in disclosing fracture patterns, particularly in complex joint fractures, where they reveal occult fractures and show the exact number of fracture components and their degree of displacement.

Multidetector computed tomography diagnosis of adult elbow fractures

Purpose: To assess acute phase multidetector computed tomography (MDCT) findings in elbow traumas. Material and Methods: Fifty‐six patients (32 M, 24 F, age 16 to 88 years, mean 44 years) underwent MDCT of the elbow due to an acute trauma during a time period of 34 months. Results: A total of 65 fractures and 3 main fracture types were established: 16 (25%) ulnar coronoid process fractures, 13 (20%) radial head fractures, and 12 (18%) humeral supracondylar fractures. Three main injury mechanisms were falling (38 (68%) patients), falling from high places (6 (11%) patients), and traffic accidents (5 (9%) patients). In 6 (11%) patients, MDCT revealed 13 occult fractures in the elbow joint compared to primary radiography. In four (7%) patients a displaced fracture fragment was detected in primary radiography, but the origin of the fragment was unclear. In all four cases, MDCT revealed the origin of the fragment. Conclusion: Radiography remains the primary imaging modality in elbow trauma, but in complex fracture patterns, where the extent of the fractures and the position or origin of dislocated fragments is not clear by radiography, the MDCT is a recommended complementary examination.

Multidetector computed tomography in acute knee injuries: assessment of cruciate ligaments with magnetic resonance imaging correlation.

Purpose: To evaluate whether non-contrast multidetector computed tomography (MDCT) for suspected acute knee fractures can also be used to evaluate cruciate ligament pathology. Material and Methods: A total of 42 patients (17–65 years) underwent four-section MDCT. The images were independently evaluated at clinical workstations by four radiologists. They assessed the integrity (normal or torn) and the best slice direction (axial, sagittal, or coronal) for visualization of the cruciate ligaments. Magnetic resonance imaging (MRI), performed within 4 weeks (mean 6 days) in relation to MDCT, was considered the gold standard. Results: Ligament integrity at MDCT: the mean interobserver proportion of agreement for a normal anterior cruciate ligament (ACL) was 0.73, for a torn ACL 0.41, for a normal posterior cruciate ligament (PCL) 0.96, and for a torn PCL 0.54. Interobserver variation for ACL was significant (P = 0.0136–0.0260), but insignificant for PCL (P = 0.3389–0.7212). Intra-observer variation was insignificant. Visualization was best in the axial and sagittal direction for ACL and PCL, respectively. At MRI, 29 normal, one partially, and 12 completely torn ACLs, and 37 normal, four partially and one completely torn PCL were found. Conclusion: MDCT can detect an intact ACL and PCL with good specificity, accuracy, and negative predictive value. The assessment of torn ligaments is unreliable.

CT of facial fracture fixation: an experimental study of artefact reducing methods

OBJECTIVES This study aimed to determine the optimal post-operative CT imaging method that enables best visualization of facial bony structures in the vicinity of osteosynthesis material. METHODS Conducted at Töölö Hospital (Helsinki, Finland), this study relied on scanning a phantom with CBCT, 64-slice CT and high-definition multislice CT with dual-energy scan (providing monochromatic images of 70-, 100-, 120- and 140-keV energy levels) and iterative reconstruction (IR) methods. Two radiologists assessed the image quality, and the assessments were analyzed. In addition, a physicist performed a semi-quantitative analysis of the metal-induced artefacts. RESULTS The three subjects most easily assessed were the loose screw and both the bone structure and the fracture further away from the screw and the plate. Soft tissues adjacent to the screw and the plate remained more difficult for assessment. Both image interpreters agreed that the artefacts disturbed their assessments under dual energy. Metal artefacts disturbed the least under multislice CT with IR [adaptive statistical iterative reconstruction (ASiR) and VEO]. Neither interpreter found metal suppression helpful in CBCT. CONCLUSIONS CBCT with or without a metal artefact reduction algorithm was not optimal for post-operative facial imaging compared with multislice CT with IR. Multislice CT with ASiR filtering offered good image quality performance with fast image volume reconstruction, representing the current sweet spot in post-operative maxillofacial imaging.

Radiocarpal Injuries: Cone Beam Computed Tomography Arthrography, Magnetic Resonance Arthrography, and Arthroscopic Correlation among 21 Patients

Background and Aims: Patients with acute or chronic wrist pain often undergo wrist arthroscopy for evaluation of chondral and ligamentous abnormalities. The purpose of this study was to compare findings of wrist arthroscopy with cone beam computed tomography arthrography and magnetic resonance arthrography. Materials and Methods: Altogether, 21 patients with wrist pain underwent cone beam computed tomography arthrography, magnetic resonance arthrography, and wrist arthroscopy. Chondral surfaces of the scaphoid, lunate, and radius facing the scaphoid and lunate were evaluated. The scapholunate ligament, the lunotriquetral ligament, and the triangular fibrocartilage complex were classified as either intact or torn. Sensitivity, specificity, positive and negative predictive values, and accuracy with 95% confidence intervals were assessed. Results: For chondral lesions (n = 10), cone beam computed tomography arthrograms showed slightly higher specificity than magnetic resonance arthrography. The sensitivity of cone beam computed tomography arthrography was also better for these lesions, except for those on the chondral surface of the lunate. For triangular fibrocartilage complex injuries (n = 9), cone beam computed tomography arthrography showed a better specificity and sensitivity than magnetic resonance arthrography. For ligamentous injuries (n = 6), cone beam computed tomography arthrograms were more sensitive, but less specific than magnetic resonance arthrography images. However, the number of lesions was very small and the 95% confidence intervals are overlapping. Conclusion: Cone beam computed tomography is an emerging imaging modality that offers several advantages over computed tomography and magnetic resonance imaging. Its usefulness particularly in ligamentous injuries should be further explored in a larger study. Cone beam computed tomography arthrography seems to offer similar sensitivity, specificity, and accuracy compared to magnetic resonance arthrography and therefore serves as a valuable option in evaluating patients with wrist pain.