The laterally tilted dens: a sign of subtle odontoid fracture on plain radiography

Type III (low) odontoid fractures may be subtle on initial plain film radiographic examination. We describe a sign on the routine open-mouth view, the laterally tilted dens, which has not been previously stressed in the radiologic literature, and is an important diagnostic sign of type III fractures of the odontoid process of the axis. In a series of 82 nontraumatized patients, no odontoid angle of less than 87 degrees (3 degrees from perpendicular) was observed. In a series of type III odontoid fractures, tilting of the dens in excess of 5 degrees was present in eight (67%) of 12 cases. This may be the only readily apparent finding on the initial cervical spine series. Of eight type III odontoid fractures in which an abnormal odontoid angle was identified, it was the only definite abnormality that could be recognized prospectively in two cases (25%) and that supported very subtle findings in two other cases (25%).     

Displaced osteochondral fracture of the lateral femoral condyle associated with an acute anterior cruciate ligament avulsion fracture: a corollary of "the lateral femoral notch sign"

Anterior cruciate ligament (ACL) rupture is usually accompanied by bone contusions resulting from impact of tibia on femur. The injury sometimes becomes manifest as a depression on the lateral femoral condyle giving rise to "lateral femoral notch" sign. The authors describe a rare case of impaction of the tibia and femur resulting in an osteochondral fracture rather than the usual bone contusion, which frequently occurs with ACL rupture. Open reduction and internal fixation of both the ACL avulsion fracture and the osteochondral fracture from the lateral femoral condyle were done, and the patient had a good outcome at 1-year follow-up. Level of evidence V.     

Hypoplastic posterior arch of C-1 in children with Down syndrome: a double jeopardy.

Radiographs of 38 children with Down syndrome (aged 2-3 years) were retrospectively evaluated for hypoplasia of the posterior arch of the C-1 vertebra. The anteroposterior dimensions of the posterior arch of C-1 were measured and compared with those of an age- and sex-matched control group. The posterior arches of C-2 to C-5 were similarly evaluated. Radiographs demonstrated hypoplasia of the posterior arch of C-1 in 26%. This anomaly of C-1 was an isolated event; sagittal diameters of C-2 to C-5 were within normal limits compared with those of the control group and published standards. Because of the known, potentially devastating atlantoaxial dislocation in Down syndrome, the increased prevalence of a second C-1 anomaly causing preexistent narrowing of the vertebral canal is of clinical concern. A hypoplastic posterior arch of C-1 may amplify the risk of spinal cord damage following atlantoaxial subluxation, as the subsequently smaller vertebral canal has less room for dorsal movement of the odontoid process. This potential "double jeopardy" of C-1 vertebral abnormalities should be recognized and assessed on cervical spine screening radiographs in children with Down syndrome.     

The calcaneal nutrient foramen: A useful sign in the differentiation of true from simulated cysts

Visualization of the nutrient foramen of the calcaneus is a useful differential sign which indicates that the area of triangular radiolucency, seen in the mid-portion of the calcaneus, represents a normal variant (simulated cyst), rather than a true solitary cyst of the calcaneus.     

Bilateral anterior glenohumeral dislocation and coracoid processes fracture after seizure: acute MRI findings of this rare association

We report a rare case of bilateral anterior shoulder dislocation associated with coracoid processes fracture after a seizure episode in a 37-year-old woman. This combination of findings is rare, especially by the presence of bilateral coracoid processes fracture. Possible mechanisms related are direct trauma of humeral heads over the coracoid processes or sudden pull of biceps short head attachment site during uncontrolled contractures. Few reports published similar combination of injuries, and to our knowledge, this is the first to demonstrate its acute features by magnetic resonance imaging. A review of the literature is also presented.     

Posteromedial tibial plateau injury including avulsion fracture of the semimembranous tendon insertion site: ancillary sign of anterior cruciate ligament tear at MR imaging.

PURPOSE: To evaluate posteromedial tibial plateau injuries of or about the semimembranous tendon insertion site and their association with anterior cruciate ligament (ACL) tears on magnetic resonance (MR) images. MATERIALS AND METHODS: A retrospective study of MR images and conventional radiographs was performed in 10 patients with posteromedial tibial plateau injuries, including avulsion fractures of the semimembranous tendon insertion site. Associated abnormalities were analyzed, including ACL tears, medial meniscal tears, and other lateral femorotibial compartment injuries. Findings from the clinical history and physical examination were correlated with radiographic and MR imaging findings. Nine patients had arthroscopically or surgically documented ACL tears. RESULTS: All 10 patients had ACL tears at MR imaging. Five patients had posteromedial tibial plateau fractures: Four had avulsion fractures of the tendon insertion site, and one had a fracture lateral to the site. Five patients had posteromedial tibial plateau bruises: Two had bruises at the tendon insertion site. Five patients had tears of the posterior horn of the medial meniscus. Two patients had posterior meniscocapsular separations. Three patients showed evidence of the O'Donoghue triad. Six patients had bruises of the lateral tibial plateau and of the lateral femoral condyle. CONCLUSION: There appears to be an association between posteromedial tibial plateau injuries and ACL tears. Posteromedial tibial plateau injuries may be predictive of ACL status.     

Intracranial vascular abnormalities: value of MR phase imaging to distinguish thrombus from flowing blood

The interpretation of conventional spin-echo and gradient-echo MR images of intracranial vascular lesions can be complex and ambiguous owing to variable effects on image intensity caused by flowing blood or thrombus. MR phase images, obtained simultaneously with conventional-magnitude images, are useful for evaluating proton motion (i.e., blood flow), and therefore can simplify the diagnosis of the presence or absence of thrombosis within a vascular structure or lesion. Fourteen patients with a variety of intracranial vascular abnormalities (aneurysms, superior sagittal sinus thrombosis, neoplasms adjacent to venous sinuses, and vascular malformations) were evaluated with conventional MR and phase imaging for the presence of blood flow. The phase images correlated with angiography in all cases. Phase imaging was not necessarily better than conventional spin-echo imaging in all cases, but it simplified the evaluation of thrombus vs blood flow in many. In three of five aneurysms, the phase images were diagnostic for evaluating lumen patency whereas the conventional images were ambiguous. Phase imaging was advantageous for detecting tumor invasion of the venous sinus when venous blood was enhanced by gadopentetate dimeglumine. A laminar flow phantom experiment determined the lower limits of sensitivity of phase imaging to be 0.5 cm/sec in the slice-select and 2.5 cm/sec in the read gradient directions. Phase imaging is a simple, reliable technique that can distinguish thrombosis from flowing blood within intracranial lesions. It is easily performed and adds no additional time to the MR examination.     

肝脏磁化传递对比MRI:无法区分健康的肝脏和肝硬化

目的使用磁化传递脉冲频率偏离波谱评估磁化传递对比MRI区分健康的肝脏和肝硬化的能力。材料与方法符合HIPAA法案的前瞻性研究已获机构审查委员会批准,并获得所有参与者的书面知情同意书,使用蛋白浓度在     

Dementing disorders: volumetric measurement of cerebrospinal fluid to distinguish normal from pathologic findings -- feasibility study

The authors describe a magnetic resonance (MR) imaging technique to quantify the severity and distribution of cerebral atrophy by using automated volumetric analysis of the distribution of cerebrospinal fluid. The MR imaging technique demonstrated high diagnostic sensitivity and specificity in a group of healthy subjects and patients with dementing diseases. The authors conclude that this approach provides valuable clinical information that is complementary to information acquired with standard diagnostic practices.     

Methods to diagnose acute anterior cruciate ligament rupture: a meta-analysis of instrumented knee laxity tests

Purpose

The aims of this meta-analysis were to determine the sensitivity and specificity of the KT 1000 Arthrometer, Stryker Knee Laxity Tester and Genucom Knee Analysis System for ACL rupture. It was hypothesized that the KT 1000 test is the most sensitive and specific. Secondly, it was hypothesized that the sensitivity and specificity of the KT 1000 arthrometer increase when the amount of Newton force is increased.

Methods

An electronic database search was performed using MEDLINE and EMBASE. All cross-sectional and cohort studies comparing one or more instrumented examination tests for diagnosing acute complete ACL rupture in living human subjects to an accepted reference standard such as arthroscopy, arthrotomy and MRI were included.

Results

The sensitivity of the KT 1000 Arthrometer with 69 N was 0.54. With 89 N, the sensitivity was 0.78 and the specificity 0.92, and with maximum manual force, the sensitivity was 0.93 and the specificity 0.93. For the Stryker Knee Laxity Tester, the sensitivity was 0.82 and the specificity 0.90. And for the Genucom Knee Analysis System, the sensitivity was 0.74 and the specificity 0.82.

Conclusion

The KT Arthrometer performed with maximum manual force has the highest sensitivity, specificity, accuracy and positive predictive value for diagnosing ACL rupture.

Level of evidence

Meta-analysis, Level I.     

大脑前动脉A1段发育不良与前交通动脉瘤的关系分析

【摘要】 目的 探讨大脑前脑动脉A1段先天性发育不良对前交通动脉（ACoA）动脉瘤形成和破裂风险的影响。方法 回顾性分析2005年1月至2015年12月接受脑血管造影的253例ACoA动脉瘤患者临床资料。单因素和多因素logistic回归模型用于分析患者年龄、性别、A1段发育不良和动脉瘤大小等风险因素,预测ACoA动脉瘤破裂可能相关因素。结果 253例患者共确诊253枚ACoA动脉瘤,其中218枚（86.2%）动脉瘤破裂,35枚（13.8%）未破裂。69.6%（176/253）动脉瘤最大径＜5 mm,其中146枚（83.0%）破裂。所有患者中141例（55.7%）表现出A1段发育不良,其中右侧106例（41.9%）,左侧仅35例（13.8%）。单因素分析显示破裂与未破裂动脉瘤患者A1段发育不良患病率比较,A1段发育不良与患者年龄和动脉瘤大小比较,差异均无统计学意义（P＞0.05）;多因素logistic回归分析显示,动脉瘤大小（OR=3.483,95%CI=1.233～9.837,P=0.018）和患者年龄（＜65岁）（OR=0.150,95%CI=0.068～0.330,P＜0.001）是ACoA动脉瘤破裂的独立预测因素。结论 ACoA动脉瘤破裂风险较高,且通常在形态较小（＜5 mm）时也易破裂。大脑前动脉A1段发育不良可能是ACoA动脉瘤形成的潜在危险因素,但它与动脉瘤大小和破裂风险无关。ACoA动脉瘤破裂的最强独立危险因素是年龄（＜65岁）和动脉瘤大小两个因素。     

Computer-aided diagnosis to distinguish benign from malignant solitary pulmonary nodules on radiographs: ROC analysis of radiologists' performance--initial experience

PURPOSE: To evaluate radiologists' performance for determining a distinction between benign and malignant pulmonary nodules on chest radiographs without and with use of a computer-aided diagnosis scheme. MATERIALS AND METHODS: Fifty-three chest radiographs that depicted 31 primary lung cancers and 22 benign nodules were used. The likelihood measure of malignancy for each nodule was determined by using an automated computerized scheme. Sixteen radiologists (nine attending radiologists and seven radiology residents) participated in an observer study in which cases were interpreted first without and then with use of the scheme. The radiologists' performance was evaluated with receiver operating characteristic analysis. RESULTS: The mean area under the best-fit binormal receiver operating characteristic curve plotted in the unit square (Az) values of radiologists who interpreted images without and with the scheme were 0.743 and 0.817, respectively. The performance of radiologists was improved significantly when the scheme was used (P =.002). However, the performance (Az = 0.889) of the computer alone exceeded these results by a substantial margin. The average change in radiologists' confidence level for interpretation without and with the scheme was highly correlated (r = 0.845) with the likelihood measure of malignancy, which was presented as computer output. CONCLUSION: This scheme for computer-aided diagnosis has the potential to improve the accuracy of radiologists' performance in the classification of benign and malignant solitary pulmonary nodules.     

Methods to diagnose acute anterior cruciate ligament rupture: a meta-analysis of physical examinations with and without anaesthesia

Purpose

The aims of this meta-analysis were to determine the sensitivity and specificity of the Lachman, pivot shift and anterior drawer test for acute complete ACL rupture in the office setting and under anaesthesia. It was hypothesized that the Lachman test is the most sensitive and the pivot shift test the most specific. Secondly, it was hypothesized that the sensitivity and specificity of all three exams increases when the examination is performed under anaesthesia.

Methods

An electronic database search was performed using MEDLINE and EMBASE. All cross-sectional and cohort studies comparing one or more physical examination tests for diagnosing acute complete ACL rupture to an accepted reference standard such as arthroscopy, arthrotomy and MRI were included.

Results

Twenty studies were identified and included. The overall sensitivity of the Lachman test was 0.81 and the specificity 0.81; with anaesthesia, the sensitivity was 0.91 and the specificity 0.78. For the anterior drawer test, the sensitivity was 0.38 and the specificity 0.81; with anaesthesia, the sensitivity was 0.63 and the specificity 0.91. The sensitivity of the pivot shift test was 0.28 and the specificity 0.81; with anaesthesia, the sensitivity was 0.73 and the specificity 0.98.

Conclusion

In the office setting, the Lachman test has the highest sensitivity for diagnosing an acute, complete ACL rupture, while all three tests had comparable specificity. When the examination was performed under anaesthesia, the Lachman test still obtained the highest sensitivity, but the pivot shift test was the most specific.

Level of evidence

Meta-analysis of diagnostic test accuracy, Level II.     

The developing anterior skull base: CT appearance from birth to 2 years of age.

PURPOSETo describe the normal CT appearance of the developing anterior skull base in children 24 months of age and younger.METHODSA retrospective review of the CT examinations of a healthy population of 61 subjects newborn through 24 months of age was performed. Two investigators independently reviewed the examinations, making measurements and observations regarding the length of the skull base, ossification pattern, and development of the crista galli, perpendicular plate of the ethmoid bone, and fovea ethmoidalis.RESULTSAt birth, the anterior skull base is largely cartilaginous. Ossification begins in the roof of the ethmoidal labyrinth laterally and spreads toward the midline. By 6 months of age, 50% of the anterior skull base has completely ossified. This percentage steadily increases over the first 2 years of life, and by 24 months, 84% of the anterior skull base is completely ossified, with a cartilaginous gap anteriorly in the region of the foramen cecum, the residual unossified portion. Ossification of the crista galli and perpendicular plate of the ethmoid bone begins around 2 months of age, shows a steady increase in ossification to 14 months of age, then increases little to 24 months of age. The fovea ethmoidalis begins development by 6 months of age, with the anterior portion the most developed in 82% of the population.CONCLUSIONThe timing and pattern of ossification we observed differ somewhat from that reported in prior radiologic and anatomic studies, with the earliest bony bridging of the ethmoidal complex to the crista galli seen as early as 2 months of age. Development of the anterior skull base follows a predictable and orderly pattern that is important for understanding how to avoid errors in interpreting CT examinations through this region.     

左胫前动脉损伤併急性血栓形成致足背动脉逆流1例

患者 男性,11岁.因骑车不慎摔伤,当即疼痛、肿胀、活动受限,未做任何处理来我院治疗.X线检查:左胫腓骨远端骨折.经穿刺内固定术治疗后,踝部肿胀未消退,足背动脉搏动较对侧减弱.