Acute knee trauma: role of ultrasound

The purpose of this study was to determine the diagnostic accuracy of high spatial resolution ultrasonography (US) in the detection of lipohemarthrosis of the knee and to evaluate this sign as criteria of intra-articular fracture. Forty-eight patients with clinical suspicion of knee fracture were prospectively examined by conventional radiography, sonography examination and computed tomography (CT) within 48 h after trauma in order to depict direct (fracture line) and indirect (lipohemarthrosis) signs of intra-articular fracture. Lipohemarthrosis was defined as a multi-layered collection in the subquadricipital recess. CT was considered as the gold standard for both direct and indirect fracture criteria. CT imaging showed direct signs of intra-articular fracture in 31 patients (65%). Among these patients, 30 (97%) had a lipohemarthrosis. Conventional radiographs showed intra-articular fracture in 26 patients (54%). Among these, 18 (69%) had a lipohemarthrosis. Sonographic examinations could not depict any direct sign of intra-articular fracture but showed a lipohemarthrosis in 29 (93%) of patients with proven fracture via CT. This allowed the depiction of four out of five occult knee fractures. The sensitivity, specificity, positive predictive value, negative predictive value of sonography for the diagnosis of lipohemarthrosis was 97, 100, 100 and 94%, respectively, compared with 55, 100, 100 and 55% with conventional radiographs. Using lipohemarthrosis as criterion of fracture, the sensitivity, specificity, positive predictive value and negative predictive value of sonography for early detection of intra-articular knee fractures was 94, 94, 97 and 89%, respectively, compared with 84, 88, 93 and 75% with conventional radiographs. We concluded that, by showing lipohemarthrosis in the subquadricipital recess, high-resolution sonography is a reliable and accurate technique for the evaluation of intra-articular knee fractures.     

Scaphoid and pronator fat stripes are unreliable soft tissue signs in the detection of radiographically occult fractures

AIM: To determine the clinical value of scaphoid and pronator fat stripes in identifying occult underlying scaphoid and distal radius fractures, respectively. MATERIALS AND METHODS: In our department, all patients with clinically suspected scaphoid fractures and normal scaphoid series of radiographs undergo magnetic resonance imaging (MRI) of the wrist. We selected 50 cases with unequivocal MRI evidence of scaphoid fracture, 50 cases with distal radius fracture and 50 cases with no MRI evidence of bony injury. All 150 initial plain radiographs were examined retrospectively in random order without knowledge of the MRI findings and the scaphoid and pronator fat stripes scrutinized. RESULTS: The scaphoid fat stripe was abnormal in only 25 cases (50%) with confirmed scaphoid fracture on MRI. The pronator fat stripe was abnormal in 13 cases (26%) with confirmed distal radius fracture. In the 50 cases with no MRI evidence of bony injury, the scaphoid fat stripe and pronator fat stripe were abnormal in 25 (50%) and 15 (30%) cases, respectively. The sensitivity and specificity for an abnormal scaphoid fat stripe was 50%. The sensitivity and specificity for an abnormal pronator fat stripe was 26 and 70%, respectively. CONCLUSION: Scaphoid and pronator fat stripes are poor predictors of the presence or absence of underlying occult fractures.     

Nondisplaced fractures of the greater tuberosity of the humerus: sonographic detection.

In this retrospective study, the sonographic appearance of fracture of the greater tuberosity of the humerus was evaluated in 17 men and 14 women aged 20-69 years with acute, semiacute, or remote shoulder trauma in whom results of rotator cuff sonography had suggested the diagnosis of such a fracture. Clinical data, radiologic reports, sonograms, and initial plain radiographs of the shoulder were analyzed; clinical follow-up information was assessed in 22 patients. Sonography showed discontinuity and irregularity of the humeral cortex in all patients. In 25 patients (81%), displaced fracture fragments could be seen. Sonographic findings were suggestive of, but not specific for, fracture. Cortical abnormalities of the humerus were identified without modification of standard scanning protocols. A humeral fracture was confirmed with radiography in 24 patients; in 10 of them, the fracture had been missed initially on plain radiographs. It is concluded that, in evaluation of soft tissues in shoulder trauma, sonography may define rotator cuff abnormalities and occasionally help in detection of occult humeral fractures.     

Scaphoid fractures: evaluation with high-spatial-resolution US initial results.

PURPOSE: To evaluate the diagnostic accuracy of high-spatial-resolution ultrasonography (US) in the diagnosis of scaphoid fractures. MATERIALS AND METHODS: In 72 hours after acute wrist trauma, 15 consecutive patients were examined for possible scaphoid fractures clinically and with conventional radiographs, including scaphoid views. Thereafter, high-spatial-resolution US was performed by two experienced radiologists blinded to the results of the previously performed investigations. High-spatial-resolution US of the scaphoid bones was performed from the palmar, lateral, and dorsal directions in the longitudinal and transverse planes. US findings indicative of a scaphoid fracture were cortical discontinuity and/or periosteal elevation. Finally, magnetic resonance (MR) images (short inversion time inversion-recovery, T1- and T2*-weighted) (ie, the standard) of the affected wrist were obtained and evaluated for a possible scaphoid fracture by two radiologists in consensus. RESULTS: Nine of 15 patients had scaphoid fractures. Seven (78%) of nine patients had positive findings at high-spatial-resolution US and five (56%) had such findings at conventional radiography (ie, four occult scaphoid fractures), with an accuracy of 87% and 73%, respectively. Two (50%) of four radiographically occult scaphoid fractures were depicted with high-spatial-resolution US. Sonographic findings of scaphoid fractures were either cortical discontinuity (n = 4), periosteal elevation (n = 2), or a combination of these two findings (n = 1). CONCLUSION: High-spatial-resolution US is a reliable diagnostic tool for the evaluation of occult scaphoid fractures and should be considered an adequate alternative diagnostic tool prior to computed tomography or MR imaging.     

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.     

Can follow-up radiography for acute scaphoid fracture still be considered a valid investigation?

AIM: To determine whether follow-up radiography is a valid diagnostic investigation in patients with suspected acute scaphoid fractures and normal initial radiographs. MATERIALS AND METHODS: Fifty sets of radiographs (initial and follow-up) were independently assessed by four expert observers for the presence or absence of a scaphoid fracture. Magnetic resonance imaging (MRI), performed in all cases, was used as the gold standard to determine the sensitivity, specificity, positive and negative predictive values of the observers' assessment of the follow-up radiograph. In addition, the reliability among observers of the follow-up radiograph was determined by reliability variance analysis. RESULTS: Of the 50 sets of radiographs, 35 patients had a scaphoid fracture and 15 were normal, as established from MRI report. For individual observer's assessment of the follow-up radiograph, sensitivities of 11, 9, 43 and 49%; specificities of 93, 93, 87 and 80%; positive predictive values of 80, 75, 88 and 85%; and negative predictive values of 31, 30, 39 and 40%. A reliability coefficient of more than 60% is needed for a diagnostic test to be considered reliable. Overall, the inter-observer reliability coefficient was 33%, with pair-wise inter-observer coefficients ranging from 18-53%. CONCLUSION: With poor sensitivity, poor negative predictive value and poor reliability, follow-up radiography cannot be considered a valid diagnostic examination for the detection of scaphoid fracture in patients with normal initial radiographs.     

Diagnostic value of cone beam computed tomography (CBCT) in occult scaphoid and wrist fractures

ObjectiveEvaluate the diagnostic value of cone beam computed tomography (CBCT) for scaphoid and wrist fractures that are missed on standard radiographs.Materials and methodsBetween September 2014 and October 2015, we prospectively enrolled 49 patients with a clinically suspected scaphoid fracture following an acute injury but had normal radiographs. Each patients underwent radiographs, CBCT and (magnetic resonance imaging) MRI within 7 days of the initial injury event. Both exam were evaluated independently by two radiologists.ResultsFor scaphoid cortical fractures CBCT sensitivity is 100% (95% CI: 75%–100%), specificity 97% (95% CI: 83%–100%). CBCT diagnosed all 24 corticals wrist fractures, corresponding to a sensitivity of 100% (95% CI: 83%–100%), specificity of 95% (95% CI: 75%–100%). Kappa agreement rate between the two radiologists was K = 0.95 (95% CI: 0.85–1) for scaphoid fractures and K = 0.87 (95% CI: 0.73–1) for wrist fractures.ConclusionsCBCT is superior to radiographs for diagnosing occult cortical fractures. Because of its low radiation dose, we believe that CBCT can be used in current practice as a replacement or supplement to radiographs to detect these fractures and optimize the cost-effectiveness ratio by limiting the number of needless immobilizations.     

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.     

Early MRI in the management of clinical scaphoid fracture

The incidence of MRI detected scaphoid and other wrist fractures was determined in a clinical setting in patients with suspicion of scaphoid injury and negative initial radiographs. The influence on subsequent patient management was examined. Patients attending Accident and Emergency over a 25 month period with suspected scaphoid fracture and normal scaphoid series plain films were referred for wrist MRI. Scans comprising T(1) weighted spin echo and short tau inversion recovery (STIR) coronal sequences were performed in a dedicated extremity low field MRI scanner within 14 days of injury. Subsequent effects on patient management were ascertained by clinician completed questionnaire. 195 patients were scanned. There were 37 scaphoid fractures (19%), 28 distal radius fractures (14%), 9 fractures of other carpal bones (5%) and 119 studies with no fracture. The management of 180 patients (92%) was altered as a result of the MRI scan. Occult fractures are present in almost two fifths of patients with suspected scaphoid fracture and normal initial plain films. Half of these are scaphoid fractures. MRI allows an early definitive diagnosis to be made, changing patient management in over 90% of cases and should be regarded as the gold standard investigation in this population.     

Occult scaphoid fractures: comparison of multidetector CT and MR imaging--initial experience

PURPOSE: To compare the diagnostic performance of multidetector computed tomography (CT) and magnetic resonance (MR) imaging in patients clinically suspected of having a scaphoid fracture and who had normal initial radiographs, with radiographs obtained 6 weeks after trauma as the reference standard. MATERIALS AND METHODS: The ethics committee approved the study, and all patients gave written informed consent. Twenty-nine patients (17 male, 12 female; age range, 17-62 years; mean age, 34 years +/- 13) underwent multidetector CT and MR imaging within 6 days after trauma. CT data were obtained with 0.5-mm collimation. For image review, 0.7-mm-thick multiplanar reformations were performed in transverse, coronal, and sagittal planes relative to the wrist. The 1.0-T MR examination consisted of coronal and transverse short inversion time inversion-recovery, coronal and transverse T1-weighted spin-echo, and coronal volume-rendered T2-weighted gradient-echo sequences. Two radiologists analyzed the CT and MR images. A binomial test was used to evaluate the significance of the differences between MR imaging and CT in detection of scaphoid fractures and cortical involvement (P < .05). RESULTS: The 6-week follow-up radiographs depicted a scaphoid fracture in 11 (38%) patients. Eight patients had a cortical fracture, while three patients had only a bandlike lucency within the trabecular portion of the scaphoid. MR imaging depicted all 11 fractures but only three [corrected] cortical fractures. Multidetector CT depicted all eight cortical fractures but failed to depict trabecular fractures. No false-positive fractures were seen on MR or CT images. Differences between MR imaging and CT were not significant for the detection of scaphoid fractures (P = .25) but were significant for cortical involvement (P = .03). CONCLUSION: Multidetector CT is highly accurate in depicting occult cortical scaphoid fractures but appears inferior to MR imaging in depicting solely trabecular injury. MR imaging is inferior to multidetector CT in depicting cortical involvement.     

MRI as a reference standard for suspected scaphoid fractures

Objectives

Some 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.

Methods

In 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.

Results

To 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).

Conclusions

The 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.The American College of Radiologists recommends MRI for diagnosis of true fractures among suspected scaphoid fractures [1]. A number of published studies cite sensitivities and specificities approaching 99% [2-9], but other studies have reported a lower sensitivity (80%) and substantial interobserver variation (κ=0.67) for diagnosis of a scaphoid fracture [2,8]. It has been difficult to agree upon a reliable reference standard for true fractures among suspected scaphoid fractures, and these studies often use only repeated radiographs 6 weeks after trauma as reference standard. However, it is also known that not all occult scaphoid fractures become apparent on repeated radiographs.It is not clear how to distinguish true fracture from other changes in bone signal that are detected with MRI. We propose that MRI of the wrists of healthy volunteers with no history of wrist or hand injury represents a reliable reference standard for the absence of an acute fracture of the scaphoid waist. By evaluating MRI scans of healthy volunteers, we may learn more about the diagnostic performance characteristics of MRI for suspected scaphoid fracture. A set of MRI scans with a reliable reference standard would also provide useful information about the reproducibility of the interpretation of MRI for suspected scaphoid fracture.The primary study question was to investigate the occurrence of false-positive diagnosis of an acute scaphoid fracture on MRI using a reliable reference standard (healthy volunteers). Secondarily we also investigated the interobserver variation of diagnosis of scaphoid fracture on MRI in healthy volunteers.     

Radiography of the carpal scaphoid. Experimental evaluation of "the carpal box" and first clinical results.

RATIONALE AND OBJECTIVES. The authors describe a new device ("the carpal box") for the radiographic detection of occult scaphoid fracture. METHODS. Fractures in the scaphoid of five cadaver specimens were mechanically produced. Subsequent examinations included conventional scaphoid radiography, multi-angle radiography, and radiography using the new device. The anatomic analysis of the specimens served as the standard for comparison. A pilot study was performed in six consecutive patients with suspected scaphoid fracture. RESULTS. Neither scaphoid radiography nor multi-angle radiography could confirm a fracture in two specimens, whereas all fractures were recognized on the carpal box radiographs. All scaphoid fractures were visualized by carpal box radiography, whereas scaphoid radiography was equivocal in one patient and negative in the other. CONCLUSIONS. Carpal box radiography may have additional value in the diagnosis of occult scaphoid fracture. This may lead to a reduction in costs and inconvenience for patients with clinically suspected scaphoid fracture and negative scaphoid radiography.     

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.     

The role of MR imaging in scaphoid disorders

The scaphoid bone of the wrist is one of the most commonly fractured bones in the body. Due to its importance in the biomechanics and functionality of the wrist, it is important to depict and characterize the type of injury. Plain radiographs and scintigraphy may fail to disclose the type and severity of the injury. In patients with normal initial plain radiographs, MR imaging can discriminate occult fractures from bone bruises and may also demonstrate ligamentous disruption. MR imaging can also discriminate the proximal pole viability versus avascular necrosis secondary to previous fracture, which is important for treatment planning. Treatment of non-united fractures with vascularized grafts can be evaluated with contrast-enhanced MR imaging. Idiopathic osteonecrosis or Preiser’s disease was originally described after trauma. The non-traumatic disorders of the scaphoid include post-traumatic osteoarthritis, inflammatory bone marrow edema in patients with rheumatoid arthritis, and osteomyelitis. MR imaging is helpful in all the above disorders to demonstrate early bone marrow edema, cartilage degeneration and associated subchondral marrow changes. The most commonly found tumors in the scaphoid are usually benign and include enchondroma, osteoblastoma and osteoid osteoma. MR imaging is not mandatory for the initial diagnosis, which should be based on plain X-ray findings.     

Occult and clinically suspected testicular tumor. Assessment using real-time sonography

The diagnostic value of real-time-sonography was evaluated in 62 patients with suspected and occult testicular tumors. In 28 patients intratesticular tumors were identified on real-time-sonograms. In addition 7 clinically occult tumors were diagnosed by real-time-sonography. It was not possible to differentiate between orchitis and tumors on sonograms (3 cases). There was correlation only between the morphologic appearance of tumors on sonograms and the corresponding histology. Using high frequency transducers sonography proved to be an useful diagnostic modality to identify or to rule out occult intratesticular tumors.     

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.     

Sonographic findings in infants with macrocrania

This study compares the sonographic and CT findings in a group of infants with macrocrania and correlates those findings with neurologic outcome to determine the diagnostic accuracy and prognostic value of sonography. Sonographic findings in 255 infants with macrocrania are described. Of the 195 term infants examined, 130 had normal sonograms, 11 (5.6%) had significant abnormalities, and 54 had increased intra- and/or extraaxial fluid spaces. Of the 60 former preterm infants, 33 had normal sonograms, four (6.7%) had significant abnormalities, and 23 had increased fluid spaces or small resolving germinal matrix hemorrhages. The patients with significant abnormalities usually had head circumferences greater than the 95th percentile and had neurologic abnormalities. There was good correlation between sonography and CT in 30 of the 36 patients evaluated by both. In six there was mild discrepancy in the volume of the extraaxial fluid. No significant abnormality was missed by sonography. CT did not contribute any additional information. Neurologic follow-up was available for 202 patients. Nineteen percent of the term infants and 24% of the former preterm infants were abnormal on neurologic follow-up. Most patients with normal sonograms were normal on follow-up. Twelve of the term and four of the preterm infants with normal sonograms were developmentally delayed on follow-up. Increased CSF in the ventricles and/or extraaxial spaces was a common abnormality, but it usually is associated with a normal neurologic outcome and represents "benign macrocrania." We conclude that an infant with an enlarged or enlarging head should have a neurologic examination and head circumference measurement. If the patient has a head circumference greater than the 95th percentile, particularly if there are abnormal neurologic findings, further evaluation is indicated. Sonography is the initial procedure recommended since it accurately evaluates ventricular size, extraaxial fluid, and congenital malformations. If sonography is normal or shows mildly increased fluid spaces, then follow-up head circumference measurement and clinical evaluation will probably suffice. CT is indicated if there is a significant abnormality on sonography that requires further clarification.     

Soft-tissue sarcoma: MR imaging vs sonography for detection of local recurrence after surgery.

To determine the value of MR and sonography in detecting local recurrences of soft-tissue sarcomas after surgery, 26 MR and sonographic studies performed in 21 patients were reviewed retrospectively. Recurrences were confirmed histologically in 12 (46%) of 26 studies. The MR images and sonograms were obtained within 1 month of each other. The findings were classified as recurrence, no recurrence, or indeterminate. Sonography was instrumental in guiding fine-needle aspiration biopsy of impalpable lesions. In two cases, the findings on sonography were indeterminate. In both of these cases, the sonograms had been obtained soon after surgery (at 2 and 4 months). The sensitivity and specificity in the detection of local recurrences were 83% and 93%, respectively, for MR and 100% and 79%, respectively, for sonography. These differences were not statistically significant. We conclude that MR and sonography appear to be equally useful in the detection of local recurrences of soft-tissue sarcomas, sonography can be used for routine follow-up and in guiding needle biopsies, sonography may be more difficult to interpret than MR during the early postoperative period, and MR should be used if sonography is inconclusive.     

Mature teratoma of the retroperitoneum: radiologic, pathologic, and clinical correlation

The authors retrospectively evaluated radiologic, clinical, and pathologic findings in 23 cases of mature teratoma arising within peri- or pararenal spaces. Radiologic studies--including abdominal radiographs (21 cases), excretory urograms (12 cases), sonograms (17 cases), and computed tomographic (CT) scans (18 cases)--were evaluated for tumor location, mass effect, calcification, fat, tumor invasion, echo pattern, and tissue characteristics. Most patients were female (3.4:1), younger than 6 months (50%), and asymptomatic. Abdominal radiography demonstrated a mass in 95%, calcium in 92%, and fat in 60% of cases in which CT revealed these components. Similarly, sonography showed uncomplicated fluid in 76% and calcium in 50% of cases. Fat was not reliably distinguished from other soft-tissue components on sonograms. The most characteristic radiologic findings of mature teratoma of the retroperitoneum are a complex mass containing a well-circumscribed fluid component of variable volume, adipose tissue and/or sebum in the form of a fat-fluid level, and calcification in either a congealed or linear strand pattern. These findings are better demonstrated by CT than by sonography.     

The distinction between femoral artery pseudoaneurysms and other causes of groin masses: value of duplex Doppler sonography

With the increasing use of percutaneous transfemoral coronary angioplasty in conjunction with thrombolytic as well as anticoagulant therapy, the sonographic evaluation of groin masses, with particular emphasis on differentiating pseudoaneurysms from hematomas and other abnormalities, has become more common. Seventy-three sonograms of the groin in 60 patients (65 different groins) were reviewed retrospectively to determine the accuracy of duplex Doppler sonography in distinguishing femoral artery pseudoaneurysm (a surgical condition) from other causes of groin masses (e.g., hematomas) that are generally treated conservatively. Nineteen cases of pseudoaneurysm, 19 cases of hematoma, and 27 other conditions were studied. Of the 73 sonograms performed, 53 included duplex Doppler studies; one Doppler study was false-negative and two were possibly false-positive. The sensitivity, specificity, and accuracy of duplex Doppler sonography in the detection of femoral artery pseudoaneurysm was 95 +/- 5.8%, 94 +/- 6.4%, and 94 +/- 6.4%, respectively (95% confidence limit). We conclude that duplex Doppler sonography is of value in the differential diagnosis of groin masses.