Supine oblique views of the cervical spine: A poor proxy for the lateral view

To determine whether supine 45° oblique radiographs of the cervical spine can accurately detect and quantify anteroposterior intervertebral plane displacements, an observer performance study was performed. A normally aligned dry cervicothoracic vertebral specimen and the same specimen with varying degrees of subluxation at one or more levels were radiographed in anteroposterior, lateral, and 45° oblique projections, in a simulated supine position. Twenty-five sets of radiographs were obtained, of which three were normal. In the remaining 22 sets, there were 43 intervertebral segments with an abnormal anteroposterior displacement. Since each intervertebral level (C2-T1) was individually evaluated, the study sample consisted of 150 intervertebral segments. Blinded to experimental conditions, six observers evaluated every intervertebral level on each lateral and oblique image in isolation. The data for each projection were compared using alternative free-response operator characteristic and free-response forced-error methodologies. Significant differences in diagnostic accuracy were detected between the horizontal lateral and the supine oblique views to detect malalignment. Although supine oblique views detected many subluxations, they produced numerous false-negative and false-positive results. The findings of this study suggest that supine oblique views may be a useful part of the standard evaluation of the acutely injured cervical spine; however, they may not reliably portray clinically important anteroposterior displacements.     

Destructive spondyloarthropathy of the cervical spine in long-term hemodialyzed patients: a five-year clinical radiological prospective study

Objective: To describe the radiographic features and progression of cervical spine destructive spondyloarthropathy (DSA) in hemodialyzed patients, and to evaluate the relationship between this disease and patient characteristics, biochemical values, and hemodialysis duration. Design and patients: Standard radiographs, and lateral flexion and extension views of the cervical spine, were performed annually for 5 years in 31 hemodialyzed patients who were divided into three groups at the commencement of the study: those showing (I) DSA, (II) vertebral rim erosions (VRE) without DSA, and (III) absence of DSA and VRE. Magnetic resonance (MR) imaging and computed tomography (CT) were performed in seven and two patients respectively. The imaging features were evaluated for the presence and progression of spondyloarthropathy and correlated with clinical and biochemical variables. Statistical analysis was performed using one-way analysis of variance. Results: The duration of hemodialysis appeared to be the main predictive factor (P=0.0003) for DSA, which was found in six patients (19%). DSA was found to correlate with higher levels of beta2-microglobulin (P<0.00001), parathyroid hormone (P<0.05), and alkaline phosphatase (P<0.05). Clinical symptoms were minimal. In two patients, MR imaging revealed changes mimicking spondylodiscitis. In another patient, CT of the craniocervical junction showed bone resorption due to a pseudotumor, and basilar invagination. Conclusions: DSA of the cervical spine is often clinically silent. Pathogenesis of DSA may be multifactorial but its progression is most influenced by the duration of hemodialysis. On MR imaging, DSA may mimic spondylodiscitis. Received: 23 January 2001 Revision requested: 27 February 2001 Revision received: 15 March 2001 Accepted: 18 April 2001     

Moving back: The radiation dose received from lumbar spine quantitative fluoroscopy compared to lumbar spine radiographs with suggestions for dose reduction

PurposeQuantitative fluoroscopy is an emerging technology for assessing continuous inter-vertebral motion in the lumbar spine, but information on radiation dose is not yet available. The purposes of this study were to compare the radiation dose from quantitative fluoroscopy of the lumbar spine with lumbar spine radiographs, and identify opportunities for dose reduction in quantitative fluoroscopy.MethodsInternationally reported dose area product (DAP) and effective dose data for lumbar spine radiographs were compared with the same for quantitative fluoroscopy and with data from a local hospital for functional radiographs (weight bearing AP, lateral, and/or flexion and extension) (n = 27). The effects of procedure time, age, weight, height and body mass index on the fluoroscopy dose were determined by multiple linear regression using SPSS v19 software (IBM Corp., Armonck, NY, USA).Results and conclusionThe effective dose (and therefore the estimated risk) for quantitative fluoroscopy is 0.561 mSv which is lower than in most published data for lumbar spine radiography.The dose area product (DAP) for sagittal (flexion + extension) quantitative fluoroscopy is 3.94 Gy cm² which is lower than local data for two view (flexion and extension) functional radiographs (4.25 Gy cm²), and combined coronal and sagittal dose from quantitative fluoroscopy (6.13 Gy cm²) is lower than for four view functional radiography (7.34 Gy cm²).Conversely DAP for coronal and sagittal quantitative fluoroscopy combined (6.13 Gy cm²) is higher than that published for both lumbar AP or lateral radiographs, with the exception of Nordic countries combined data.Weight, procedure time and age were independently positively associated with total dose, and height (after adjusting for weight) was negatively associated, thus as height increased, the DAP decreased.     

Optimisation of patient dose for the horizontal beam technique in lateral lumbar spine radiographic examinations

In the emergency department, patients undergoing lateral lumbar spine radiography examinations are positioned either lying on their side on an X-ray table with the X-ray beam vertical or lying supine on a trolley with the X-ray beam horizontal. The measured dose–area product (DAP) values were found to differ significantly, typically 1.3 Gy cm² for those patients examined on the X-ray table and 2.7 Gy cm² for those on a trolley. This work investigates the reason for higher DAP values with the horizontal beam technique. The UK’s current recommended national diagnostic reference level (NDRL) for the lateral lumbar spine is 2.5 Gy cm². The measurements of body diameter on volunteers showed that rotating the patients from their side to their back resulted in an increase in tissue thickness of between 2 cm and 9 cm for the lumbar region. X-ray absorption increases exponentially with increasing tissue thickness. An increase of 5 cm in body diameter for a lateral lumbar spine at 93 kV will increase the DAP by more than two-fold. Mathematical modelling and measurements with polymethyl methacrylate provided data to predict the tube potential increase necessary to reduce the DAP. For the horizontal beam technique, the tube potential was increased from 93 kV to 102 kV and the average DAP reduced to 2.3 Gy cm². Radiographic technique should be understood when auditing the dose. Tube potential must be increased to optimise the horizontal beam technique. The 2.5-Gy cm² NDRL relates predominantly to the more common vertical beam technique. Separate local diagnostic reference levels for horizontal and vertical beam techniques are recommended.It is a requirement under the Ionising Radiation (Medical Exposure) Regulations 2000 [IR(ME)R] [1] that hospitals in the UK monitor the dose levels for groups of standard-sized patients undergoing common radiographic examinations. A dose–area product (DAP) meter attached to the X-ray unit provides a quick and easy method to routinely monitor the dose. Guidance on the measurement of the patient dose [2,3] states that data should be collected for a minimum of 10 adult patients with a weight range of between 50 kg and 90 kg. The mean value of the dose from the sample should then be compared against a locally defined diagnostic reference level (DRL) [4]. Where local DRLs still have to be established, it is a common practice to adopt national diagnostic reference levels (NDRLs). The NDRLs are generally taken from the data published by the Health Protection Agency—Radiation Protection Division. Its national database contains dose data submitted from many hospitals across the UK, and summary reports are published every 5 years [5]. It is a requirement of IR(ME)R that, when the mean values of measured doses exceed the DRL, the cause is investigated and corrective action is taken appropriately.     

Evidence against the use of lumbar spine radiography for low back pain

AIM: To review abnormalities reported on plain radiographic examination of the lumbar spine in patients referred with low back pain by general practitioners. Additionally, we evaluated and stratified the prevalence of these abnormalities by age. Finally, the diagnostic impact of lumbar spine radiography for the diagnosis of degenerative change, fracture, infection and possible tumour, was modelled. MATERIALS AND METHODS: A retrospective review of 2007 radiographic reports of patients referred with low back pain for lumbar spine radiography to a large radiology department was performed. The reports were classified into different diagnostic groups and subsequently stratified according to age. The potential diagnostic impact of lumbar spine radiography was modelled by using the prevalence of conditions studied as pre-test probabilities of disease. RESULTS: The prevalence of reported lumbar spine degeneration increased with age to 71% in patients aged 65-74 years. The overall prevalence of fracture, possible infection, possible tumour was low in our study population: 4, 0.8 and 0.7%, respectively. Fracture and possible infection showed no association with age. Possible tumour was only reported in patients older than 55 years of age. CONCLUSION: Although the prevalence of degenerative changes was high in older patients, the therapeutic consequences of diagnosing this abnormality are minor. The prevalence of possible serious conditions was very low in all age categories, which implies radiation exposure in many patients with no significant lesions.     

Development of a mathematical model of the cervical spinal canal and its use in detecting early pathologic changes

Summary Detection of subtle osseous changes on plain film roentgenograms of the cervical spine is essential in expediting the evaluation of suspected intraspinal tumors. It is our experience that the earliest osseous changes in such cases involve thinning or erosion of the adjacent pedicles and/or lamina and a subsequent increase in the oblique diameter of the cervical spinal canal. A statistical model is established which accurately describes the normal cervical vertebral column in terms of its spinal canal size (sagittal and oblique diameters) as well as pedicle and lamina thickness. Data was obtained from a series of 86 normal exams. Six surgically proven cases of cervical intraspinal tumors were analyzed using this model. Variations from expected normal values reveal statistically significant osseous changes involving thinning of the lamina and increased oblique diameter of the spinal canal, while the sagittal diameter of the canal remains normal. Because of these findings we feel that oblique cervical spine films should be included in the initial evaluation of neural canal tumors.     

Complications related to osteopenia in the thoracic spine on admission chest radiographs of substance abuse detoxification patients

Objective. To assess the prevalence of complications related to osteopenia in the thoracic spine (anterior wedging and fish vertebrae) of patients admitted for substance abuse detoxification. Design and patients. We retrospectively identified 150 sequential patients admitted to our drug and alcohol detoxification ward in whom posteroanterior and lateral admission chest radiographs and clinical charts were available for review. There were 116 men and 34 women with a mean age of 37 years (range 19–67 years). Thirty-eight patients were admitted for drug detoxification, 37 for alcohol detoxification, and 75 for drug and alcohol detoxification. These patients were compared with 66 age- and sex-matched controls from our hospital’s employee health service. Two radiologists reviewed all chest radiographs for the presence of anterior wedging and fish vertebrae in the thoracic spine and other nonspinal fractures. Serum calcium and inorganic phosphorus levels were recorded for the substance abuse detoxification patients. Results. Forty-nine percent (n=73) of detoxification patients had complications of osteopenia in the thoracic spine including: anterior wedging (n=47), fish vertebrae (n=21), or both (n=5). Twenty-four percent (n=36) of patients had an elevated serum inorganic phosphorus level and one patient had an elevated serum calcium level. Patients with anterior wedging or fish vertebrae included: 45% (n=45) of patients below age 40 years, 35% (n=12) of women, 41% (n=15) of drug detoxification patients, 58% (n=22) of alcohol detoxification patients, 48% (n=36) of drug and alcohol detoxification patients, and 47% (n=17) of patients with elevated serum inorganic phosphorus (P=NS). Six percent (n=9) of our study population had nonspinal fractures on their chest radiographs. Twenty-one percent (n=14) of controls had complications of osteopenia in the thoracic spine (all anterior wedging). This prevalence differed significantly (P<0.05, chi-squared) from the study population. Conclusion. Osteopenia-related anterior wedging and fish vertebrae in the thoracic spine are common findings on chest radiographs of patients hospitalized for substance abuse detoxification. Serum inorganic phosphorus and calcium levels did not correlate with the presence of anterior wedging or fish vertebrae.     

A baseline study of entrance dose and image quality for lumbar spine radiography in Calabar, Nigeria

PurposeTo obtain baseline data for implementing optimisation protocols in Nigeria, a study of the patient entrance surface doses (ESDs) and image quality for lumbar radiography in the two major hospitals in Calabar, Nigeria has been carried out.MethodA total of 74 patients cutting across the two hospitals were monitored during lumbar X-ray examination for entrance surface doses (ESDs) using Lithium Fluoride Thermoluminescent dosimeters (LiF-TLDs). Image quality of ensuing radiographs was studied by three experienced Radiologists using the European Commission (EC) criteria for lumbar radiography.ResultsMean patient entrance dose for the studied population was about 10.5 mGy (AP) and 23.1 mGy for the lateral projection. Third quartile ESD values suggest that up to 75% of the exposed population in lumbar radiography may be receiving doses above the EC reference level. Image quality scores against a reference image were marginally above average. There was no correlation between dose and image quality per radiograph. Results confirm the need for optimisation of procedure in the area.ConclusionProcedural changes are suggested in order to lower the patient doses and improve on the image quality of radiographs. These results are to be used as a reference for future review after the optimisation protocol is put in place.     

The incidence and prognostic significance of radiological abnormalities in soft tissue injuries to the cervical spine

The radiographs and initial clinical findings of 73 patients who had sustained trauma to the cervical spine without bony injury in vehicle collisions were reviewed. The patients were also re-examined clinically two years after the injury. Forty eight (65.8%) had abnormal radiographs at presentation — prevertebral soft tissue swelling in 15 (20.6%), degenerative changes in 15 (20.6%), and an angular deformity between two adjacent vertebral bodies in 27 (37.0%). Prevertebral soft tissue swelling was found to have no significance with respect to clinical outcome and showed no association with the presence of an angular deformity. Degenerative changes are associated with a poor prognosis. The presence of an angular deformity was found to carry a good prognosis in this group of patients. The exact mode of injury is not associated with any specific radiographic appearance except that roll overs and side collisions are more likely to cause angulation in the cervical spine.     

正常胎儿标本颈、胸、腰段脊柱发育的MRI研究

目的探讨正常胎儿标本颈、胸、腰段脊柱和椎体体积随孕周生长变化规律。方法利用3.0 T MR扫描仪对55具17~42孕周胎儿尸体标本行全脊柱三维T2WI序列扫描,其中孕妇自发性流产获得标本20具,母体因严重疾病引产获得标本35具,胎儿标本均来源于山东大学医学院断层影像解剖学研究中心。标本经CT扫描均未发现脊柱异常。采用OsiriX软件(www.osirix-viewer.com),在重建横断面图像上沿椎体边缘逐层勾画椎体轮廓,获得脊柱颈、胸、腰段脊柱体积,将其除以各段椎体个数,获得椎体单位体积。逐一测量腰椎5个椎体体积。将颈、胸、腰段脊柱体积和腰椎椎体体积与孕周作回归分析,并分析各段脊柱增长规律。结果(1)胎儿颈、胸、腰段脊柱体积与孕周增长呈线性相关关系,线性回归方程分别为:颈段脊柱体积(mm3)=-1260.937+81.235×孕周(R2=0.974,P<0.05);胸段脊柱体积(mm3)=-5933.521+347.503×孕周(R2=0.972,P<0.05);腰段脊柱体积(mm3)=-5130.912+294.473×孕周(R2=0.976,P<0.05)。(2)胎儿脊柱生长速度:胸段>腰段>颈段;同一孕周阶段内,脊柱体积:胸段>腰段>颈段;椎体单体积增长速度及增长倍数:腰椎>胸椎>颈椎。(3)腰1~腰5椎体体积增长与孕周亦呈线性相关关系。结论孕中晚期胎儿标本颈、胸、腰段脊柱椎体体积的增长与胎龄呈良好的相关性,且不同节段生长速度不一。     

Relationship of elongated anterior tubercle to incomplete segmentation in the cervical spine

 Purpose. To describe the elongated anterior tubercle of cervical vertebrae, its association with incomplete segmentation, and its analogy to sacralization of the lower lumbar vertebrae. Materials and methods. Cases with elongated anterior tubercles of the cervical vertebrae detected on plain radiography were collected during routine practice and their features analyzed on plain radiography and MR imaging. Five patients, aged 19–40 years, with the anomaly seen on plain radiography were included in this study. MR imaging was undertaken in one patient. Results. Hypertrophy of the anterior tubercle was associated with incomplete segmentation in three of the five patients. Oblique views were adequate to demonstrate its nature. Conclusions. The association of an elongated tubercle and incomplete segmentation is similar to partial sacralization at the lumbosacral junction. Clinically it is important that these anomalies are not mistaken for pathologic findings.     

On the creation of a segmentation library for digitized cervical and lumbar spine radiographs

In this paper, we address the issue of computer-assisted indexing in one specific case, i.e., for the 17,000 digitized images of the spine acquired during the National Health and Nutrition Examination Survey (NHANES). The crucial step in this process is to accurately segment the cervical and lumbar spine in the radiographic images. To that end, we have implemented a unique segmentation system that consists of a suite of spine-customized automatic and semi-automatic statistical shape segmentation algorithms. Using the aforementioned system, we have developed experiments to optimally generate a library of spine segmentations, which currently include 2000 cervical and 2000 lumbar spines. This work is expected to contribute toward the creation of a biomedical Content-Based Image Retrieval system that will allow retrieval of vertebral shapes by using query by image example or query by shape example.     

Influence of medicolegal factors in the use of cervical spine and head computed tomographic examinations in an emergency setting

Estimates suggest that defensive medicine, including radiologic studies, costs Americans more than $21 billion annually. As a result of our prior evaluation of 13,228 emergency department patients, we already knew that cervical spine and head computed tomographic examinations were the third and fourth most commonly ordered studies in our emergency department. The emergency medicine, obstetrics/gynecology, surgery, and internal medicine physicians at The Ohio State University agreed to cooperate in a study to determine the factors that influence the decision to order these examinations. Overall, 26 (28%) of the physicians surveyed had personal experience in a medical malpractice lawsuit. Attending physicians in all groups were more concerned about potential medicolegal consequences, compared to residents and fellows (P=0.055) when ordering cervical spine examinations. This coincides with the finding that attending physicians were more likely to have been sued (P<0.001). Emergency medicine physicians were more likely to order one of these examinations if the patient had demanded or requested it (P<0.001) and were more likely to weight physical examination findings more heavily (P=0.007) when compared to other physician groups. Finally, all physician groups combined suggested that approximately 33% of all cervical spine and 39% of all head computed tomographic examinations could be avoided if there were no worries about medicolegal consequences.     

Epidural fat interposition between dura mater and spinous process: a new sign for the diagnosis of spondylolysis on MR imaging of the lumbar spine

The purpose of this study was to assess the diagnostic value of epidural fat interposition between the dura mater and spinous process of L5 as an indirect sign of spondylolysis on mid-sagittal MR imaging of the lumbar spine. Mid-sagittal T1-weighted MR images of the lumbar spine of 85 patients with spondylolysis and 93 patients without pars interarticularis fractures were randomized and evaluated by a masked reader. After a training sample of five cases, the reader was asked to note the presence or absence of epidural fat interposition between the dura mater and spinous process of L5 on the randomized images. The epidural fat interposition between the dura mater and spinous process of L5 was noted in 67 out of the 85 patients with spondylolysis (78.8%) and three of the patients without pars interarticularis fracture (3.2%). The difference was statistically significant (P<0.01). This sign has a specificity of 96.7%, sensitivity of 78.8%, positive predictive value of 95.7%, negative predictive value of 83.3% and accuracy of 88.2% for diagnosis of spondylolysis. Epidural fat interposition between the dura mater and spinous process may be a helpful sign for the diagnosis of spondylolysis on mid-sagittal MR imaging of the lumbar spine.     

CT for trauma to the base of the skull and spine in children

Summary Five patients have been selected to demonstrate the diagnostic accuracy of CT in cases of traumatic damage to the base of the skull and spine in infants and children. CT is superior to any other diagnostic radiological technique as bone and soft tissues are usually equally well demonstrated during one visit to the Radiology Department. Thus, CT is considered to be the primary investigative procedure of choice to evaluate trauma of the base of the skull and spine in infants and children.     

Observer agreement in the reporting of knee and lumbar spine magnetic resonance (MR) imaging examinations: Selectively trained MR radiographers and consultant radiologists compared with an index radiologist

Purpose

To assess agreement between trained radiographers and consultant radiologists compared with an index radiologist when reporting on magnetic resonance imaging (MRI) examinations of the knee and lumbar spine and to examine the subsequent effect of discordant reports on patient management and outcome.

Methods

At York Hospital two MR radiographers, two consultant radiologists and an index radiologist reported on a prospective, random sample of 326 MRI examinations. The radiographers reported in clinical practice conditions and the radiologists during clinical practice. An independent consultant radiologist compared these reports with the index radiologist report for agreement. Orthopaedic surgeons then assessed whether the discordance between reports was clinically important.

Results

Overall observer agreement with the index radiologist was comparable between observers and ranged from 54% to 58%; for the knee it was 46–57% and for the lumbar spine was 56–66%. There was a very small observed difference of 0.6% (95% CI −11.9 to 13.0) in mean agreement between the radiographers and radiologists (P = 0.860). For the knee, lumbar spine and overall, radiographers’ discordant reports, when compared with the index radiologist, were less likely to have a clinically important effect on patient outcome than the radiologists’ discordant reports. Less than 10% of observer's reports were sufficiently discordant with the index radiologist's reports to be clinically important.

Conclusion

Carefully selected MR radiographers with postgraduate education and training reported in clinical practice conditions on specific MRI examinations of the knee and lumbar spine to a level of agreement comparable with non-musculoskeletal consultant radiologists.     

Effect of a full and empty bladder on radiation dose to the uterus, ovaries and bladder from lumbar spine CT and X-ray examinations

This is a quantitative study of the effect of a full and empty bladder on the position of the uterus, ovaries and bladder relative to the lumbar spine. Data are used to estimate the difference in radiation dose to these organs from performing a lumbar spine CT investigation or a lateral lumbar spine radiograph with a full bladder compared with an empty bladder. 12 women of child-bearing age underwent pelvic magnetic resonance scans with full and empty bladders. The positions of the uterus, ovaries and bladder were matched with the radiation dose distribution that would have occurred either side of the inferior boundary of the CT scan volume and the lateral lumbar spine radiograph. These radiation dose profiles were measured on phantoms using a combination of ionization chambers and thermoluminescent dosemeters. When the bladder was emptied, the mean position of the endometrial cavity fundal tip moved from 4.1 cm to 6.1 cm inferior to the centre of the L5/S1 disc space, and from 0.87 cm to 1.12 cm anterior to the centre of the L5/S1 disc space. This movement on micturation would have reduced the mean dose to the uterine internal fundal tip during a pelvic CT scan from 6.8 mGy to 3.9 mGy, which represents a mean reduction of 43% (range 12-67%). The mean dose from a lateral lumbar spine examination would have been reduced from 197 microGy to 126 microGy. The change in ovary position results in the mean ovary dose being reduced by 48% for the lumbar spine CT scan and by 43%) for a lateral lumbar spine radiograph. When the bladder was emptied, the average position of the bladder wall moved from 7.2 cm to 10.3 cm inferior to the L5/S1 disc space. This change in bladder position reduces the mean dose to the wall of a full bladder from 5.7 mGy for a CT scan and 114 microGy for a lumbar spine radiograph to 2.2 mGy and 42 microGy, respectively, for an empty bladder.     

CT后处理技术引导的豌豆骨X线摄影体位设计

目的:探讨CT图像后处理技术在豌豆骨X线摄影特殊体位设计中的应用.方法:选择30例既往的腕部CT检查病例,对其CT影像进行后处理重建,在腕部MIP影像中,分别测出A、B两名医师和高级放射技师C观察豌豆骨侧位的最佳投影角度,并进行统计学处理.结果:A、B、C3组数据具有较好的一致性,最佳的豌豆骨侧位X线摄影投射角度为腕关节侧位外旋(24.43±3.44)°,经验证具有较好的临床应用效果.结论:CT图像后处理技术可用于普通X线摄影技术的体位设计中,使其更进一步完善.     

The value of ultrasonic examination of the lumbar spine in infants with specific reference to cutaneous markers of occult spinal dysraphism

AIM: To present part of the rationale behind the recent update to the M12 guideline in The Royal College of Radiologists' publication "Making the best use of a department of clinical radiology", 4th edition 1998, which stated that ultrasound was useful in screening for dysraphism in infants with cutaneous markers such as sacral dimple or hairy patch. MATERIALS AND METHODS: Over a 10-year period a total of 223 infant lumbar spines were scanned, for various clinical indications. Forty of these patients had already had abnormalities detected antenatally by foetal ultrasonography. One hundred and eight-three patients had abnormalities detected on postnatal clinical examination; most of these had various cutaneous markers, some had other congenital abnormalities. RESULTS: There were a total of 29 patients with dysraphism; 24 were detected antenatally and five postnatally. Of the five, two had two or more cutaneous markers and three had anorectal anomalies. All 86 of the patients with simple sacral dimples, pits or sinuses were normal. CONCLUSION: As an isolated abnormality, simple dimples or pits are not useful markers of spinal dysraphism. The authors suggest a new imaging protocol, resulting in improved diagnostic efficiency.