Assessing radiographically occult upper extremity fractures with dedicated extremity MRI

Purpose: To examine the utility of low-field, dedicated extremity MRI for assessing acute upper extremity trauma in patients with radiographs that are negative for fracture. Secondly, to determine which sequences are most useful when screening for fractures. Methods: Forty-four of 46 patients with acute upper extremity trauma and initial radiographs negative for fracture were imaged with a 0.2-T MRI system. Findings were verified with follow-up clinical assessment and plain radiography. Results: In 21 patients, dedicated extremity MRI demonstrated 26 ultimately proven occult fractures, none of which were seen on the initial conventional radiographs. True fractures demonstrated marrow edema and a linear fracture line on low-field MRI. One bone contusion showed edema with no fracture line and was misdiagnosed as a fracture. Low-field MRI correctly identified 23 remaining patients with no fracture. Sensitivity and specificity for fracture in the 44 patients successfully imaged were 100 % and 96 %, respectively. Additionally, 21 soft-tissue injuries were found incidentally by MRI. However, these may not merely be incidental findings of an acute nature, but may very well be chronic, and therefore merit no specific treatment. T1-weighted gradient-echo and short-tau inversion recovery sequences demonstrated the fracture line and marrow edema to best advantage, and were thus the most useful sequences to assess fractures on low-field MRI. Conclusion: Extremity MRI is highly sensitive and specific for radiographically occult fractures of the upper extremity and can also identify associated soft-tissue injuries. In our study, the management was altered in 45 % of the patients following MRI. When adequate sequences are used this modality can direct appropriate therapy while obviating the added expense and morbidity of unnecessary immobilization and follow-up imaging of patients without fracture.     

The role of MRI in the assessment of scaphoid fracture healing: a pilot study

Twenty-two patients with fracture of the scaphoid treated by cast immobilisation underwent clinical examination, radiography and MR scanning 6 weeks after injury. On clinical and plain radiographic criteria alone, 12 patients were considered sufficiently healed to warrant mobilisation. The remaining 10 patients were considered unhealed and were immobilised for a further period. A musculoskeletal radiologist, blinded to the clinical diagnosis, reviewed the MRI scans. Of the 10 patients considered unhealed, 5 had the MR appearances of a united fracture, based on normal marrow signal across the fracture line on T1-weighted images. Of the 12 patients deemed to have united, union could be confirmed by MRI criteria in only 5, but all 12 were healed at 1 year. The results suggest that MRI can provide additional information in this group of patients. It can confirm bony union in a high proportion of patients deemed clinically non-united. Its use in this context will allow a more rapid mobilisation and return to normal function. The significance of persistent MR signal abnormalities in patients who have clinical and radiographic signs of healing merits further study. Received: 13 March 2000, Revised: 12 May 2000, Accepted: 15 May 2000     

Can chest and abdominal trauma CT eliminate the need for plain films of the spine? – Experience with 329 multiple trauma patients

Purpose: To compare the accuracy of spine plain films with chest and abdominal trauma CT in detection of spine fractures. Methods: The study prospectively enrolled 329 multiple trauma patients. Of these, 38 patients had both chest CT for trauma and thoracic spine plain films, and 87 patients had both abdominal CT for trauma and lumbar spine plain films. Results: Of the fractures visible at either chest trauma CT or thoracic spine plain film examination, all were diagnosed on CT and 62 % on plain films. Of fractures visible at either abdominal trauma CT or lumbar spine plain films, 94 % were diagnosed on CT and 67 % on plain films. The one false negative CT involved an articular process fracture, which was visible but not mentioned, in a patient with a sacral fracture. Conclusion: Evaluation of the digital scout images and bone windows when a patient has chest and abdominal trauma CT appears to be as accurate as thoracic and lumbar spine plain films in the evaluation of spinal trauma.     

Imaging of the congenitally absent cervical pedicle: avoidance of misdiagnosis in a setting of trauma

An enlarged neuroforamen may be due to a congenitally absent cervical pedicle. We report a case initially misdiagnosed as a cervical fracture. CT and MRI are recommended for correct diagnosis and prevention of unwarranted treatment.     

The role of the reversed oblique radiograph in trauma of the foot and ankle

The objective of this study was to demonstrate the statistical significance of a reversed oblique radiograph of the foot in patients with ankle or foot trauma. In 100 consecutive patients a reversed oblique radiograph of the foot was taken in addition to the conventional plain films. Ten of 29 fractures were not visualised on the conventional films of foot and ankle and could only be diagnosed on the reversed oblique film. In 7 of these 10 cases an avulsion fracture at the anterolateral aspect of the calcaneus was present. This additional reversed oblique film of the foot seems to be of considerable importance, especially when an anterolateral avulsion fracture of the calcaneus is clinically suspected. Received: 1 December 1998; Revision received: 9 June 1999; Accepted: 14 July 1999     

Magnetic resonance imaging: a cost-effective alternative to bone scintigraphy in the evaluation of patients with suspected hip fractures

Objective. To evaluate the cost-effectiveness of magnetic resonance imaging (MRI) compared with radionuclide bone scan in the evaluation of patients with clinically suspected hip fractures. Design. The medical records of all patients who had been seen in the emergency room over a 4-year period with a clinically suspected hip fracture, negative or equivocal plain films, and either a subsequent bone scan or MRI examination were retrospectively reviewed. The time to diagnosis, admission rate, and time to surgery were determined. A two-sample t-test was used to assess the statistical significance of the results. A theoretical cost analysis was performed using current charges to estimate all expenses. Patients. Forty patients (11 male, 29 female; age 28–99 years) satisfied our inclusion criteria. Results and conclusions. Twenty-one patients had bone scans (six with fractures), and 19 had MRI (four with fractures). The time to diagnosis was 2.24±1.30 days for bone scanning and 0.368±0.597 days for MRI (P<0.0001). Twenty patients in the bone scan group were admitted compared with 13 in the MRI group. The time to surgery was at least 1 day longer in patients undergoing bone scanning. Bone scanning resulted in higher patient costs compared with MRI because of the delay in diagnosis. In the evaluation of patients with suspected hip fractures, early MRI is more cost-effective than delayed bone scanning. Further prospective studies comparing the cost-effectiveness of early MRI with early bone scanning are needed.     

Cost analysis of different protocols for imaging a patient with acute flank pain

The aim of this study was to analyse the costs of different diagnostic approaches to patients with acute flank pain. Four different diagnostic approaches were considered: (a) spiral CT without contrast medium (CM); (b) plain film, ultrasonography (US) and intravenous urography (IVU) – the latter procedure is used in our department in cases still unsolved following the former investigations (28 % in our experience); (c) plain film, US and spiral CT without CM (as an alternative to IVU in 28 % of cases); and (d) IVU. The cost of each procedure in a university hospital was calculated, following analysis of the differential costs of each investigation (equipment, depreciation and maintenance costs, related materials and services, radiologists, radiographers, nurses) and their common costs (auxiliary personnel and indirect internal costs). Finally, we calculated the full cost of each procedure and applied it to the different diagnostic approaches. The full cost of each approach was: (a) spiral CT without CM = 74 Euro; (b) plain film, US and IVU (28 %) = 66.89 Euro; (c) plain film, US and spiral CT without CM (28 %) = 64.93 Euro; (d) IVU = 80.90 Euro. Intravenous urography alone or in unsolved cases is not to be considered because it provides higher costs and worse diagnostic results, whereas X-ray dose to patient is almost equal between IVU and spiral CT. Spiral CT integrated to plain film and US in unsolved cases could be preferred because of lower cost and dose to patient, though reaching a diagnostic conclusion may take longer than an immediate spiral CT. Received: 29 February 2000; Revised: 22 May 2000; Accepted: 23 May 2000     

Acetabular insufficiency fractures

Isolated acetabular insufficiency fractures are relatively uncommon occurrences that are difficult to diagnose if not suspected. Patients may present with variable signs and symptoms including emergent, incapacitating hip pain. Plain radiography is typically negative. Early diagnosis is important because most patients respond well to conservative therapy. This report describes three cases of isolated insufficiency fractures of the acetabulum diagnosed by magnetic resonance imaging (MRI).     

A longitudinal insufficiency fracture of the tibia in association with a healed chronic osteomyelitis

Longitudinal stress fracture of the tibia often present with an atypical clinical presentation which can be mistaken for osseous tumor or osteomyelitis. We present a case of longitudinal stress fracture of the tibia which occurred in a patient with healed chronic osteomyelitis of the tibia. Magnetic resonance imaging failed to make the correct diagnosis. Accurate diagnosis was only obtained by helical CT which showed the longitudinal fracture line. Magnetic resonance imaging showed only non-specific signs of bone marrow edema, suggesting recurrence of osteomyelitis. Magnetic resonance imaging can be misleading in the absence of direct visualization of the fracture line. Received: 30 September 1999; Revised: 26 April 2000; Accepted: 2 May 2000     

Occult and secondary injuries missed by plain radiography of the cervical spine in blunt trauma patients

Background: Plain radiography does not visualize every cervical spine injury sustained by blunt trauma victims. The purpose of this study was to examine the prevalence and types of injuries missed by plain radiographs of the cervical spine and determine how frequently such radiography fails to detect any cervical spine injury. Methods: Images from all radiographic studies performed on blunt trauma victims presenting to 21 participating institutions were reviewed to compile an exhaustive list of all CSIs sustained by each individual. These injuries were then compared with the injuries detected by plain radiography alone. Patients were classified as having a “sentinel” injury if one or more of their injuries were visible on plain radiographs. Patients were classified as having a radiographically “occult” injury if none of their injuries were visible on plain radiographs. The number and types of injuries missed on plain radiographs were then separately tabulated for the sentinel and occult injury groups. Results: Plain radiographs were completed in 570 of 818 victims of acute cervical spine injury and revealed 702 of 1,056 injuries. Plain films failed to detect 98 occult injuries present in 60 patients (10.5 %), and failed to detect 256 secondary injuries in 510 patients (89.5 %) who had a sentinel injury identified. Plain radiographs failed to reveal 79 of 136 (58.1 %) lateral mass injuries and 67 of 105 (63.8 %) lamina injuries, making these the most frequent sites of missed injury. Conclusions: Plain radiographs frequently fail to reveal injuries to the cervical spine, particularly those involving the lamina and lateral mass. The majority of the missed injuries represent secondary injuries in patients with a sentinel injury identified on these films. However, plain films fail to detect any injury in a minority of injured patients.     

Prevalence and clinical significance of misinterpretations of plain radiographs by orthopedic residents in a minor trauma emergency room

Purpose: (1) To determine the accuracy of interpretation of plain radiographs by orthopedic residents in a minor trauma emergency room, (2) to evaluate the clinical significance of misinterpretations for patient management, and (3) to evaluate the necessity of routine plain film review by a radiologist and an efficient patient recall system. Materials and methods: Our retrospective study evaluated discrepancies in plain film reading between orthopedic residents and radiologists. A total of 2283 radiographic examinations were evaluated for discrepancies. The medical records and X-rays in misinterpreted cases were assessed by a musculoskeletal radiologist and a staff orthopedist. The misinterpretations were categorized based on their clinical significance and influence on medical care. Misinterpretations which required immediate change in treatment or mandated further work-up were considered to have high clinical significance. Results: Forty-six (2 %) of the 2283 interpretations were defined as misinterpretations. Of the 46 cases, 27 (59 %) were missed fractures, 5 (11 %) were missed tumors, and 7 (15 %) were false positive readings of normal films. Twenty-one (46 %) of the misinterpretations had significant consequences. Forty-one percent of missed fractures had a high clinical significance, whereas only 14 % of false positive readings had a high clinical significance. Conclusion: The accuracy of plain film interpretation by orthopedic residents in the minor trauma setting is high (98 %). Nevertheless, 46 % of the misinterpretations have significant clinical consequences. This indicates that all emergency trauma films should be reviewed by an experienced radiologist, and an expedient method of informing the orthopedic department of any discrepancies in reading is recommended.     

Cervical spine injury in the very elderly

Background: Elderly patients are known to be at increased risk of cervical spine injuries. This propensity for injury becomes more important as the population of mobile elderly individuals increases. The present study seeks to examine the incidence and spectrum of spine injury among patients aged 80 years or greater, and to examine the efficacy of a decision rule for obtaining cervical spine radiography in this extreme age group. The decision rule would determine whether imaging could be avoided in patients who have none of the following: (1) posterior midline cervical spine tenderness; (2) focal neurological deficit; (3) abnormal level of alertness; (4) evidence of intoxication; or (5) clinically apparent distracting painful injury. Methods: All blunt trauma victims presenting to participating emergency departments underwent clinical evaluation prior to radiographic imaging. The elements of the decision rule were assessed and documented in each patient prior to radiographic imaging. The presence or absence of cervical spine injury was subsequently based on the final interpretation of all radiographic studies supplemented by a review of neurosurgical and risk management logs from each participating hospital. Data on all patients aged 80 years or greater were sequestered from the main database for separate analysis. Results: The study enrolled 34,069 individuals, including 818 patients (2.4 %) with cervical spine injuries. This population contained 1,070 patients (3.1 % of all cases) aged 80 or greater, 50 of whom (4.7 %) sustained cervical spine injuries. Injuries to the craniocervical junction (particularly C2 and the odontoid) accounted for 47.3 % of the injuries in the elderly, but only 28.6 % of injuries in younger patients. Older fracture victims were also likely to have more injuries (2.54 injuries/patient) than their younger counter parts (1.78 injuries/patient). The decision rule correctly identified all very elderly cervical spine injury victims [sensitivity 100.0 %; confidence interval (CI) 92.9–100.0 %], and designated 132 patients as “low-risk,” yielding a negative predictive value of 100.0 % (CI 97.3–100.0 %). Conclusions: The very elderly are at increased risked of cervical spine injury, particularly injury to the craniocervical junction. They also tend to have more extensive injuries than younger patients. Despite the increased risk of injury, the decision rule performed well in the very elderly, and allowed correct identification of all cervical spine injury victims.     

Prevalence of exclusively and concomitant pelvic fractures at magnetic resonance imaging of suspect and occult hip fractures

Pelvic fractures may occur together with hip fractures as a result of low energy trauma. It is unclear whether they do require special attention. There are conflicting results in the literature about the prevalence of both concomitant hip and pelvic fractures as well as exclusive pelvic fractures. It has been reported that hip fractures and obturator ring fractures are mutually exclusive. To retrospectively analyze the prevalence of exclusively pelvic as well as concomitant hip and pelvic fractures in patients examined with MRI after low-energy trauma in elderly. During 9 years, 316 elderly patients had been examined with MRI for suspected or occult hip fracture after a fall. A fracture was diagnosed when MRI showed focal signal abnormalities in the subcortical bone marrow, with or without disruption of adjacent cortices. One observer reviewed all studies. A second observer verified all studies with hip fractures. Follow-up was available for all but two patients that died prior to hip surgery. The prevalence of concomitant pelvic and femoral neck or trochanteric fractures was statistically compared using chi-squared test for categorical variables. Hip fractures were found in 161 (51 %) patients of which 29 (9 %) had concomitant pelvic fractures. There were exclusively pelvic fractures in 82 (26 %) patients of which 65 (79 %) were on the traumatized side only. In 73 patients, there were no fractures. Occult or suspected hip fractures are not infrequently associated with pelvic fractures. Exclusively pelvic fractures are not uncommon.     

MRI of breast tumors

Breast MRI is increasingly used as an adjunct to conventional imaging modalities, particularly in diagnostic problem cases, but also for pre-operative staging. It is an extremely sensitive technique, with relatively limited specificity. To avoid both, false-positive, but particularly false-negative diagnoses, it is imperative to be familiar with the varying MRI appearance of benign and malignant breast tumors. This review serves to give an overview of the different criteria that can be used for differential diagnostic purposes. Moreover, practical guidelines are given to help with the adequate management of enhancing lesions.     

Cervical spine injury: accuracy of helical CT used as a screening technique

Objective: The study objective was to determine the sensitivity and specificity of a helical CT technique to screen for cervical spine injury in a high-risk trauma population. Materials and methods: The helical CT reports for a consecutive series of 601 high-risk adult blunt trauma victims were reviewed. Findings were confirmed using an independent reference standard, which consisted of additional cervical spine imaging (CT, MRI, or radiography), operative findings, autopsy results or clinical outcome. Results: Sensitivity and specificity of helical CT for injury were 77/81 (95 %; 95 % confidence limits: 90–100 %) and 484/520 (93 %; 95 % confidence limits 91–95 %) respectively. Four false negative cases were comprised of three missed ligamentous injuries and one missed fracture. False positive cases (n = 36) were mostly attributed to possible facet fracture (n = 6), possible ligamentous injury (n = 8) or technically inadequate scan (n = 6).The overall accuracy of the helical CT protocol for cervical spine injury in this population was 561/601 (93 %; 95 % confidence limits 91–95 %). Conclusion: Helical CT has high accuracy for cervical spine injury. We believe that helical CT should be the preferred imaging strategy in high-risk blunt trauma patients.     

The advantages of MRI in the detection of occult hip fractures

While the displaced hip fracture can be visualized easily by plain radiography, the non-displaced fracture may be radiographically occult and require different imaging modalities, e.g., MRI for proper visualization. The accuracy of readers and cost advantages of utilizing MRI have not been assessed. Therefore, we undertook a study of these factors. The medical records of all patients who had visited the emergency room from June 2002 until May 2003 with a clinically suspected hip fracture, negative or equivocal plain film and subsequent MRI examination were retrospectively reviewed. Two senior and two junior radiologists independently evaluated both the MR images and radiographs of all 33 patients in a blinded study. One of three possible evaluations was described for the images of each modality: absence, presence or possibility of fracture. The economic consequences of using MRI in the detection of occult hip fractures were calculated. For all four doctors participating in this study, MRI proved to be far more sensitive and specific in the detection of occult hip fractures than radiography. Using the MR images, the senior radiologists identified the occult hip fracture patients with 100% accuracy and were in complete agreement. The agreement between junior and senior radiologists was high (average =0.75). MRI also detected soft tissue injuries in 39% of the patients that could not be identified with radiography. Adoption of the new protocol using MRI saves hospitals from €242 to 627 per patient. By shortening the time to diagnosis and permitting a superior visualization of both bone and soft tissue injuries, MR imaging prevents unnecessary hospitalization and delays in definitive treatment. MR images should be assessed by senior radiologists.     

Magnetic resonance imaging of occult fractures of the proximal femur

The evaluation of the painful hip in the elderly osteoporotic patient with normal plain radiographs can be difficult. We studied 15 osteopenic patients with normal plain radiographs and suspected hip fractures with magnetic resonance (MR) imaging and found MR to be an excellent aid in detecting occult fractures. A clear fracture was seen in 10 of the 15 patients, who then underwent surgical repair based on the MR study. The remaining patients had no MR-demonstrable fracture and were successfully treated nonoperatively. Some believe that a negative bone scan in this population of patients should be repeated within 3 days prior to a definitive no fracture decision being made. Unfortunately, bone scanning lacks spatial resolution, and increased osteoblastic activity may be caused by other pathologic processes besides fracture. Two of the 15 patients had MR-demonstrated bone infarcts near the fracture. One patient also had femoral head osteonecrosis on the side of the fracture. One patient with metastatic prostatic carcinoma had a hip fracture and one patient with metastatic breast carcinoma had no fracture. Not only is MR imaging an excellent technique for delineating occult fractures, but due to its spatial resolution, associated bone disorders adjacent to fractures can be detected in most instances. From a cost perspective, rapid diagnosis and early treatment of an occult femoral fracture is advisable. A reduced hospital stay pending diagnosis and the early institution of definitive therapy also decrease the chance that a simple non-displaced fracture will displace and require more complex management with resultant increased morbidity and cost. We propose that, especially in elderly, osteopenic patients with normal plain radiographs and a high index of suspicion for hip fracture, MR can serve as the sole additional imaging study in most instances.Presented at the Annual Meeting of the American Roentgen Ray Society, San Francisco, April 1993     

A comparison of bone scintigraphy and MRI in the early diagnosis of the occult scaphoid waist fracture

Objective. To determine the accuracy of MRI in the assessment of the radiographically occult scaphoid fracture. Design. This prospective study compared the sensitivity and specificity of MRI for detection of radiographically occult scaphoid fractures with bone scintigraphy (BS), the currently accepted imaging modality of choice. Consecutive patients with clinical signs of a scaphoid injury but no evidence of fracture on plain radiographs at presentation and after 7–10 days were evaluated by MRI and BS. All images were reported in masked fashion and the sensitivities and specificities of the imaging modalities determined. All patients with a scaphoid fracture demonstrated by MRI or BS were followed for at least a year after injury. Patients. Forty-three subjects (aged 12–74 years) had both MRI and BS carried out on average 19 days from the injury date. Results and conclusions. Six patients (14%) had scaphoid waist fractures. There were other bony injuries in a further six. In 40 patients there was agreement between the BS and MRI findings. In three cases there was discrepancy between the imaging modalities; in all three MRI was found to be the more sensitive and specific. MRI could become the investigation of choice for this injury.     

The lesser curvature fold: a new plain film finding for diagnosing a paraesophageal hernia

This case report describes a new plain film X-ray finding for a paraesophageal hernia. A plain film of the chest containing a new finding for a paraesophageal hernia was later confirmed by barium study. This new finding was a horizontal fold traversing the air-filled diaphragmatic hernia sac, with the fold representing the opposed sides of the stomach's lesser curvature. Recognition of this finding can hasten the diagnosis of this potentially life-threatening type of hiatal hernia.     

Gallstone ileus: CT findings

Gallstone ileus is a rare complication of recurrent gallstone cholecystitis. The classic radiographic triad of small bowel obstruction, pneumobilia and ectopic gallstone on abdominal plain radiograph is described with CT imaging. Because of the better resolution of CT compared with abdominal radiography and its recent accession to emergency use, radiologists should be aware of CT findings of gallstone ileus. We report a case in which gallstone ileus was initially diagnosed by CT. Received: 30 July 1999; Revised: 18 October 1999; Accepted: 18 October 1999