Oblique Axial Planes Research Articles

95% prevalence of abnormality on hip MRI in elite academy level rugby union: A clinical and imaging study of hip disorders.

To identify the prevalence of hip disorders in elite level academy rugby union players using clinical and radiological investigation comparing findings to active controls. Cross-sectional, controlled study. Participants were assessed clinically using validated questionnaire (HAGOS) and physical testing procedures. Active ROM of all hip movements were measured using a goniometer and hip-specific clinical tests including the FABER and the Thomas test examined functional hip motion. Physical tests were compared to age, gender and activity matched controls. The rugby-playing participants underwent dedicated non-arthrographic 3T MRI imaging of the hip in axial oblique, sagittal and coronal planes to assess anatomical abnormality. The rugby cohort had significantly reduced ROM of internal/external rotation, extension and FABER scores compared to the controls. Symptoms were reported by 65% of rugby players (HAGOS symptom score <89.3) versus 15% in controls. There was a 95% prevalence of abnormality on MRI (19 of 20 players); 80% of the elite rugby players had labral pathology, 55% had a cam deformity (45% left sided 30% right-sided) and 25% had either unilateral or bilateral chondral wear. The prevalence of abnormality on MRI of the hip is high in rugby players at 95% of study participants. The percentage reporting symptoms was lower at 65% of the cohort although this was significantly higher than (non-rugby) matched controls at 15% of participants. Rugby players demonstrated significantly reduced ROM of the hip compared to controls. Further prospective research is required to investigate the long term sequelae of these findings.

Radiological Assessment of Femoroacetabular Impingement Morphology Using Computed Tomography in an Asymptomatic Young Population

Background:: Femoroacetabular impingement (FAI) is one cause of hip pain, and is an under-recognized cause of early osteoarthritis, especially in young and active people. The prevalence of FAI in adults is approximately 10 – 15% and depending on the clinical and radiographic findings, two types of impingement (which are often present in combination) can be distinguished: the cam type and the pincer type. Most patients (86%) have a combination of both forms of impingement. Objectives:: The aim of our study was to evaluate the prevalence and gender differences in the radiological parameters associated with cam and pincer FAI morphologies in an asymptomatic young population, using computed tomography (CT). Patients and Methods:: A retrospective study was performed on 200 individuals (400 hip joints), ranging from 15 - 40 years of age, who were seen in our hospital between July of 2013 and April of 2014 for nonspecific abdominal pain. Multiplanar reformatted CT images of these patients were assessed for the existence of radiological abnormalities, and six measurements (acetabular version angle, acetabular index, lateral center-edge angle, alpha angle in the oblique axial plane, alpha angle in the radial [one o’clock position] plane, and femoral head neck offset) were made relating to the FAI. Results:: The data showed that 69.2% of the women’s joints and 60.5% of the men’s joints had at least one abnormal parameter associated with the FAI. Of the joints, 34.25% had two or more abnormal parameters, and in 38 (19%) of the patients, these abnormalities were bilateral. Unlike previous studies, we found that only 15% of the joints had mixed FAI morphologies. Conclusion:: The prevalence of radiological parameters associated with FAI is high, even in an asymptomatic young population. This high frequency of features may suggest that the threshold values have been set too low in the current literature, or that these findings may reflect anatomical variation rather than true pathological abnormalities.

Elasticity of the Coracohumeral Ligament in Patients with Adhesive Capsulitis of the Shoulder.

To evaluate the elasticity of the coracohumeral ligament (CHL) in healthy individuals and patients with clinical findings suggestive of unilaterally involved adhesive capsulitis of the shoulder (ACS). The institutional review board approved this single-institution prospective study, which was performed between November 15, 2012, and July 8, 2014. Informed consent was obtained from all subjects. Measurement of CHL thickness was performed in the axial oblique plane under shoulder maximal external rotation. Shear-wave elastography (SWE) was used to evaluate elasticity of the CHL in healthy individuals (11 men, 19 women aged 22-62 years) and those with clinical findings suggestive of ACS (nine men, 11 women aged 41-70 years). SWE was performed in the shoulder-neutral position and under maximal external rotation. The Wilcoxon signed-rank test was performed to compare the thickness and elastic modulus of the CHL between bilateral shoulders. In all subjects, the CHL elastic modulus was larger under maximal external rotation than in the neutral position (P < .001 for all). For healthy subjects, there was no significant difference in the CHL elastic modulus between the dominant and nondominant shoulders. For patients presumed to have ACS, the CHL thickness was significantly greater in the symptomatic shoulder than in the unaffected shoulder (P < .001). The CHL elastic modulus of the symptomatic shoulder (median, 234.8 kPa; interquartile range [IQR], 174.4-256.7 kPa) was significantly greater than that of the unaffected shoulder (median, 203.3 kPa; IQR, 144.1-242.7 kPa) in the shoulder-neutral position (P = .004) but not under maximal external rotation (P = .123). When bilateral shoulders were maintained at the same angle of external rotation, the CHL elastic modulus was greater in the symptomatic shoulder than in the unaffected shoulder (P = .005). In patients with clinical findings suggestive of ACS, SWE showed that the CHL is stiffer in the symptomatic shoulder than in the unaffected shoulder.

Radiological Investigation of the Variance of Ossicular Position in Microtic Ears

OBJECTIVE: To radiologically investigate the malformations in microtic ears so as to provide assistance for canaloplasty of the external auditory meatus and tympanoplasty operation. MATERIALS and METHODS: High-resolution computed tomography (HRCT) data of 48 patients with unilateral congenital microtia and aural atresia were studied. Multi-planar reconstruction (MPR) was performed to investigate the anatomic anomaly. The oblique axial and coronal planes were evaluated, on which the tympanic bone remnant was shown and the ossicular mass appeared with the largest size. The angles between the oblique axial/coronal planes and standard axial/coronal planes were measured and named α and β. The thickness of the atresia plate was measured on the oblique planes. The measurements in the microtic ears were compared with data from the normal side and 40 ears in 20 control individuals without ear malformations as well. RESULTS: In most of the microtia patients, the α angle in the affected side (19.78°±7.42°) was larger than the α angle in the normal side (15.30°±4.60°), while the β angle in the affected side (16.77°±13.43°) was smaller than the β angle in the normal side (27.46°±6.87°). The thickness of the atresia plate was less than the thickness of the cribriform area in the normal side. A significant correlation was found between the Marx classification and the thickness of the atresia plate. CONLUSION: HRCT evaluation using MPR is an important complement for the Jahrsdoerfer scoring system. The investigation is of great realistic significance. Preoperative measures for individual patients can provide guidance for canaloplasty and tympanoplasty operation.

An analysis of the diagnostic measurements for assessing cam-type femoroacetabular impingement using computed tomography

Background: Femoroacetabular impingement can lead to early osteoarthritis. Diagnosis is primarily radiographic relying on the alpha angle and the anterior offset ratio. There is no clear consensus on how to best diagnose impingement. Methods: This is a retrospective analysis using the alpha angle and anterior offset ratio in the oblique axial and radial planes of 81 preoperative CT scans of patients who underwent hip resurfacing. Results: There were no differences in average alpha angles between image planes. CT was validated for use of these measurements, and the anterior offset ratio was described for the first time in the radial plane using reformatted CT images. Conclusions: More precise methods may be needed to screen for femoracetabular impingent that address issues of sensitivity and variability.

T2-SPACE MRI for the ocular motor nerves in the brainstem of normal controls

To study the detail functional anatomy of ocular motor nerves in the brainstem by high-resolution magnetic resonance imaging (MRI). Sixty eight normal subjects with high resolution MRI were recruited in our study. The ocular motor nerves at the brainstem were performed using 3-dimensional, T(2)-weighted Turbo-Spin-Echo sequence with high sampling efficiency sequence (3D T(2)-SPACE), Parameters: TR = 1000 ms, TE = 134 ms, averages = 2, thickness = 0.8 mm, FOV = 225 mm×225 mm, matrix = 384×384, total scanning time is 4 min 2 s. Nerves in the brainstem were observed in oblique axial, oblique sagittal and coronal planes acquired with multi-planar reformation (MPR). The diameters of oculomotor nerves (CN3) and abducens (CN6) in the brainstem were measured in 68 normal subjects on MR images by 2 neuro-radiologists. All of 136 CN3 and CN6 of the cisternal segment were well demonstrable in 68 normal subjects (100%). Trochlear nerves (CN4) were depicted 87%. The diameters of CN3 and CN6 in the cistern were 2.2 mm, 1.3 mm, had no linear correlation with age. There were no significant difference between the results of the 2 radiologist (F = 2.557, 1.329, P = 0.085, 0.271). T(2)-SPACE sequence combined with MPR could precisely show the ocular motor nerves, as well as the relationship with adjacent structures in the cistern. The exact data measurement can provide more accurate anatomical basis for some special forms of neuropathic strabismus.

Shared Morphology of Slipped Capital Femoral Epiphysis and Femoroacetabular Impingement in Early-onset Arthritis

A subclinical form of slipped capital femoral epiphysis (SCFE) can lead to subtle morphologic abnormalities, such as cam-type femoroacetabular impingement (FAI). Femoroacetabular impingement is a mechanical hip abnormality that typically affects young populations and leads to hip pain and premature osteoarthritis. Imaging is critical to diagnosis, whether by radiograph, magnetic resonance imaging, or computed tomography. The authors investigated the use of imaging to detect characteristics of subclinical SCFE and cam-type FAI in patients undergoing hip resurfacing. They retrospectively assessed computed tomography scans of 81 hips from 75 patients. Measurements were taken of the proximal femur and included the alpha angle, head-neck tilt, and anterior offset taken in both the conventional oblique axial plane and the radial plane. The cohort consisted of 68 men and 13 women with an average age of 52 years. Ninety percent of hips on the oblique axial view and 95% of hips on the radial view were found to have pathologically increased alpha angles. Negative correlations were found between the alpha angle and head-neck tilt and positive correlations between head-neck tilt and anterior offset ratio. Sixty percent and 68% of hips in the oblique axial and radial planes, respectively, were abnormal for the alpha angle, head-neck tilt, and anterior offset ratio, strongly suggesting SCFE morphology. This study's results show similarity in morphology between cam-type FAI and SCFE, known precursors to osteoarthritis, in an early arthritic patient population.

Predictive factors of diagnostic accuracy of CT-guided transthoracic fine-needle aspiration for solid noncalcified, subsolid and mixed pulmonary nodules

The aim of this study was to analyse factors predicting the diagnostic accuracy of computed tomography (CT)-guided transthoracic fine-needle aspiration (TTFNA) for solid noncalcified, subsolid and mixed pulmonary nodules, with particular attention to those responsible for false negative results with a view to suggesting a method for their correction. From January 2007 to March 2010, we retrospectively reviewed the CT images of 198 patients of both sexes (124 males and 74 females; mean age, 70 years; range age, 44-90) used for the guidance of TTFNA of pulmonary nodules. Aspects considered were: lesion size and density, distance from the pleura, and lesion site. Multiplanar reformatted images (MPR) were retrospectively obtained in the sagittal and axial oblique planes relative to needle orientation. The overall diagnostic accuracy of TTFNA CT-guided biopsy was 86% for nodules between 0.7 and 3 cm, 83.3% for those between 0.7 and 1.5 cm, and 92% for those between 2 and 3 cm. Accuracy was 95.1% for solid pulmonary nodules, 84.6% for mixed nodules, and 66.6% for subsolid nodules. The diagnostic accuracy of CT-guided TTFNA in relation to the distance between the nodule and the pleural plane was 95.6% for lesions adhering to the pleura and 83.5% for central ones. The diagnostic accuracy was 84.2% for the pulmonary upper lobe nodules, 85.3% for the lower lobe and 90.9% for those in the lingula and middle lobe. In 75% of false negative and inadequate/insufficient cases the needle was found to lie outside the lesion, after reconstruction of the needle path by MPR. The positive predictive factors of CT-guided TTFNA are related to the nodule size, density and distance from the pleural plane. The most common negative predictive factor of CT-guided TTFNA is the wrong position of the needle tip, as observed in the sagittal and axial oblique sections of the MPR reconstructions. The diagnostic accuracy of CT-guided TTFNA can therefore be improved by using the MPR technique to plan the needle path during the FNA procedure.

Measuring the Effect of Pars Plana Vitrectomy on Vitreous Oxygenation Using Magnetic Resonance Imaging

To study the effect of pars plana vitrectomy (PPV) on vitreous oxygenation (pO2) using magnetic resonance imaging (MRI). Patients due to undergo PPV for either macular hole or epiretinal membrane were recruited. MRI scanning was performed 1 week before and at least 3 months after PPV. MRI T1 mapping was performed using an inversion recovery-true fast imaging with steady-state precession (TrueFISP) sequence at several inversion times, from a single slice positioned through the center of both eyes in the axial oblique plane. Additional phantom data were measured in porcine vitreous, to define the relationships between T1 relaxation times and balanced salt solution (BSS), to simulate human vitreous and aqueous, respectively, for a suitable pO2 range (5-70 mm Hg). Pre-PPV pO2 was also measured intraoperatively using a polarographic oxygen probe. Eleven participants (age range 59-84) were recruited; two declined the post-PPV scan. Corrected T1 times indicated that the mean (±SD) pO2 increased significantly following PPV, from 13.2 ± 5.8 to 34.5 ± 8.0 mm Hg (P < 0.001). In the nonsurgical (control) eye, pO2 did not change significantly from the first to second MRI scan (13.7 ± 7.8 vs. 16.3 ± 8.7 mm Hg, P = 0.239). Mean pO2 measured intraoperatively was 7.2 ± 0.6 mm Hg (n = 10). These results confirm that vitrectomy substantially increases vitreous pO2. MRI is a noninvasive technique that can be used to study vitreous oxygenation in both vitrectomized and nonvitrectomized eyes.

Cam and Pincer Femoroacetabular Impingement: CT Findings of Features Resembling Femoroacetabular Impingement in a Young Population Without Symptoms

The purpose of this study was to use CT to determine the presence of radiologic parameters associated with cam and pincer femoroacetabular impingement (FAI) in a young population without symptoms. A retrospective review of 50 patients (age range, 20-40 years) with no current or previous hip disorder who underwent CT of the abdomen and pelvis was conducted. Multiplanar images were reformatted with a soft-tissue and bone algorithm and assessed for the presence of parameters associated with FAI; alpha angle greater than 55°, femoral head-neck offset less than 8 mm, angle of acetabular version less than 15°, lateral center edge angle greater than 40°, acetabular index less than 0°, pistol-grip deformity, acetabular crossover, and prominent posterior wall signs. At least one abnormal parameter was present in 66% of joints, and two or more abnormal parameters were present in 29% of joints. In seven patients the findings were bilateral. Parameters of mixed morphologic characteristics (cam and pincer) were found in 22% of joints. In side-by-side comparison, high alpha angles were seen in 36 joints measured in the radial plane compared with only three joints measured in the axial oblique plane. The CT finding of FAI-like features was made with high frequency in a young symptom-free population. Cutoff values for defining morphologic abnormalities associated with FAI may have been set too low in the current literature. Alpha angle measurements in the radial plane may be a more accurate quantitative assessment of asphericity of the femoral head-neck junction than are measurements in the axial oblique plane.

Patellar maltracking is prevalent among patellofemoral pain subjects with patella alta: An upright, weightbearing MRI study

The purpose of this study is to determine if patellar maltracking is more prevalent among patellofemoral (PF) pain subjects with patella alta compared to subjects with normal patella height. We imaged 37 PF pain and 15 pain free subjects in an open-configuration magnetic resonance imaging scanner while they stood in a weightbearing posture. We measured patella height using the Caton-Deschamps, Blackburne-Peel, Insall-Salvati, Modified Insall-Salvati, and Patellotrochlear indices, and classified the subjects into patella alta and normal patella height groups. We measured patella tilt and bisect offset from oblique-axial plane images, and classified the subjects into maltracking and normal tracking groups. Patellar maltracking was more prevalent among PF pain subjects with patella alta compared to PF pain subjects with normal patella height (two-tailed Fisher's exact test, p<0.050). Using the Caton-Deschamps index, 67% (8/12) of PF pain subjects with patella alta were maltrackers, whereas only 16% (4/25) of PF pain subjects with normal patella height were maltrackers. Patellofemoral pain subjects classified as maltrackers displayed a greater patella height compared to the pain free and PF pain subjects classified as normal trackers (two-tailed unpaired t-tests with Bonferroni correction, p<0.017). This study adds to our understanding of PF pain in two ways-(1) we demonstrate that patellar maltracking is more prevalent in PF pain subjects with patella alta compared to subjects with normal patella height; and (2) we show greater patella height in PF pain subjects compared to pain free subjects using four indices commonly used in clinics.

OP02.05: Disparities in first trimester screening in the US

Objectives: Mid-sagittal plane for examination of the posterior brain is part of the routine 11–13 weeks scan, but the oblique axial plane is not. Our objective was to asses the feasibility of including visualization of the oblique axial plane in combination with midsagittal plane for examination of the posterior fossa as part of the routine 11–13 week scan. Methods: Transvaginal followed by a transabdominal 2D and 3D ultrasound scan were performed in 100 consecutive well dated 11–13 weeks normal fetuses. A protocol including habitual landmarks of the head for mid-sagittal and axial planes was considered. Also a more oblique axial plane to evaluated posterior fossa, the acute angle observed in the transition between cerebral peduncles and the thalami and specific distances was included. Results: In the mid-sagittal plane, the two echogenic horizontal lines, representing the posterior border of the brainstem and the choroid plexus of the fourth ventricle and the specific distances, were obtained in 72% of cases. In the axial plane, shape of the skull and butterfly like choroid plexus were seen in all cases. Oblique axial plane at the level of the diencephalon and midbrain was easily obtained, and the acute angle of the peduncles and thalamis were observed in 96%. Anteroposterior diameters of the cisterna magna and fourth ventricle, and the distance between the aqueduct of Sylvius and the occipital bone were seen in 94% of the cases. Intraand interobserver repeatability showed no differences. Conclusions: Oblique axial plane for examination of the posterior fossa is easy and fast, and should be considered in combination with the mid-sagittal plane part of a routine 11–13 week scan. However, more studies should be done to confirm its utility to detection of fetuses with spina bifida.

Capsular Ligaments of the Hip: Anatomic, Histologic, and Positional Study in Cadaveric Specimens with MR Arthrography

To demonstrate the anatomy of the capsular ligaments of the hip by using magnetic resonance (MR) arthrography. Institutional policies were followed regarding cadaver use. MR arthrographic images of 10 fresh human cadaveric hips were obtained by using a positioning device to arrange the hip joint in different controlled positions. MR appearances of the capsular structures were noted and correlated with those seen on anatomic slices and dissections. Two readers working in consensus graded the visibility of these structures. Tissue samples were collected for histologic analysis. An MR positional study was performed to evaluate the length of these capsular ligaments and the subjective classification of their appearance as either taut or lax in extension, flexion, abduction, adduction, and internal and external rotation. The hip capsule inserts proximally and continuously to the acetabular rim periosteum. Distally, it has a firm anterior insertion at the femoral intertrochanteric line and no posterior osseous insertion. The inferior band of the iliofemoral ligament was best evaluated in the sagittal, axial, and axial oblique planes, and it serves a restrictive function in extension; the superior band of the iliofemoral ligament was best evaluated in the coronal and axial oblique planes, and it serves a restrictive function in external rotation; the ischiofemoral ligament was best evaluated in the axial and axial oblique planes, and it serves a restrictive role in internal rotation; the pubofemoral ligament was best evaluated in the sagittal plane, and it serves a restrictive function in abduction; and the zona orbicularis could be evaluated equally well in any imaging plane. MR arthrography enables visualization of the capsular ligaments of the hip.

Impact of Image Analysis Methodology on Diagnostic and Surgical Classification of Patients With Thoracic Aortic Aneurysms

For patients with thoracic aortic aneurysms (TAA), aortic size on imaging is widely used to guide clinical decision making. This study examined the impact of methodological variance on aortic quantification. We studied enrollees in the National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions. Aortic size on computed tomography was quantified by 2 linear methods; cross-sectional dimensions in axial (AX) and double oblique (DO) plane. Calculated area was compared to planimetry. Established cutoffs (area/height>10 cm2/m, diameter≥5 cm) for prophylactic TAA repair were used to compare surgical eligibility by each method. Fifty subjects were studied. Aortic size differed between AX and DO at all locations (p≤0.001), with magnitude greatest at the sinotubular junction (4.8±1.1 vs 4.0±1.0 cm, p<0.001). The difference between AX and DO correlated with aortic angular displacement (r=0.37, p<0.01), which was threefold larger at the sinotubular junction (37±12 degrees) than the ascending aorta (12±5 degrees; p<0.001). At all locations, aortic area calculated using DO yielded smaller differences with planimetry than AX (p<0.05). DO and planimetry yielded equal prevalence (24%) of subjects eligible for prophylactic TAA repair based on area-height cutoff, whereas AX prevalence was higher (44%; p=0.006). Using a linear cutoff, AX yielded over a twofold greater prevalence of surgically eligible subjects (56%) than did DO (24%; p<0.001). Established linear methods for aortic measurement yield different results that impact surgical eligibility. DO yielded improved agreement with planimetry and differed with AX in proportion to aortic geometric obliquity. Findings support DO measurements for imaging evaluation of subjects with TAA.

Oblique axial MR imaging of the normal anterior cruciate ligament bundles

The anterior cruciate ligament (ACL) is composed of the anteromedial and posterolateral bundles [1, 2]. Although these two bundles are closely aligned anatomically, they do have distinct biomechanical functions with the anteromedial bundle stabilizing the knee in flexion and the posterolateral bundle stabilizing the knee in extension [1–5]. Most ACL tears are complete with the tear extending across both bundles. Partial tears of the ACL are less frequently encountered and may involve both bundles to a similar degree or one bundle predominantly. Although complete ACL tears do not have the capacity to heal, a limited blood supply to the ACL via the medial geniculate artery does allow healing of partial tears [6, 7]. Correct assessment regarding the presence, severity, and location of partial tears is relevant since delayed recognition of a partial tear can result in progression to complete tear [6]. Also, if only one bundle is predominantly torn, isolated single bundle reconstruction rather than full ACL graft reconstruction may be undertaken [8, 9]. Early evaluation of partial ACL tears could possibly improve clinical and surgical management [10]. A prerequisite to diagnosing ACL bundle injury on MR imaging is clear delineation of both bundles and awareness of their normal appearance. Orthogonal planes can delineate the normal ACL bundle structure in only 42% of knees [11]. In this study, we describe a new oblique axial plane for imaging the normal ACL bundles on MR imaging; evaluate how well the normal ACL bundles can be evaluated on this plane compared to the standard sagittal, coronal, and axial planes [12–15]; and describe the normal MR appearances.

Lateral ankle ligaments: MR arthrography with anatomic correlation in cadavers

Objective The purpose of our study was to use magnetic resonance (MR) imaging and MR arthrography to demonstrate the anatomy of the lateral ankle ligaments using standard and oblique imaging planes in cadavers. Material and methods MR imaging of ten cadaveric ankles was performed before and after intra-articular administration of contrast solution. Proton-density MR images were acquired in standard and oblique imaging planes. MR imaging was correlated with anatomic sections. Measurements using oblique imaging planes were obtained to characterize the morphology of the lateral ligaments. Results The anterior talofibular ligament (ATFL) had a variable number of bands in all specimens, separated by fat signal oriented obliquely parallel to the long axis of the ligament. The fibular attachment of ATFL was located in close proximity to the fibular attachment of the distal band of the anterior tibiofibular ligament (AITFL). The angle formed by the calcaneofibular ligament (CFL) and the fibular shaft varied with different ankle positions. Special axial oblique plane best demonstrated the CFL. The posterior talofibular ligament (PTFL) was multi-fasciculated in appearance. Dorsiflexion of the ankle joint helped elongate the PTFL and best depicted this ligament in its entirety in the axial plane. Conclusion Oblique imaging planes parallel to the long axis of the individual ligaments may improve visualization of the anatomy of the lateral ankle ligaments. The orientation of the lateral ankle ligaments is affected by the position of the talocrural and subtalar joints. Understanding the morphology of the lateral ankle ligaments can help radiologists diagnose abnormalities of these ligaments.

Isovoxel-Based Morphology of Hippocampi and Amygdalae: A Comparison of Manual and Automated Volume Measurements

This study evaluated the correlation between manual and automated morphometric measurements of hippocampi and amygdalae. Twenty-three patients with no history of seizures and normal electroencephalograms were examined with a standardized MRI protocol that included isovoxel volumetric acquisitions of the brain. Images were evaluated in axial-oblique plane to trace manually the grey matter contours of hippocampi and amygdalae obtaining their volumes. They were also processed automatically carrying out segmentation and sub segmentation aligning images (AC-PC) and standardizing them into Talairach space to obtain then comparable grey matter volumes. Tabled results were age, gender and volumes of each side from both, manual and automated measurements. Forward stepwise multiple regression analyses were carried out considering sex and age as independent and hippocampi-amygdalae as dependent variables. Linear regression analyses were then carried out considering for the total of cerebral hemispheres each manual measurement as independent and automatically obtained volumes as dependent variables. In the multiple regression analyses the following values were obtained: age-gender vs. manual measurements showed r=0.83; r(2)=0.69; adjustedr(2)=0.64; F(3,19)=14.36 while age-gender vs. automated values showed r=0.86; r(2)=0.74; adjustedr(2)=0.70; F(3,19)=18.81. Linear regression between manual and automated measurements for all hemispheres showed for hippocampus: r=0.97; r(2)=0.95; F(1,44)=896.59. For amygdala results were: r=0.94; r(2)=0.89; F(1,44)=391.11. The results of these analyses suggest that both manual and automated procedures of measurement are highly consistent. A regression between age and volumes of both hippocampus and amygdala was also noted.

The preliminary application of magnetic resonance arthrography in the diagnosis of acetabular labral tears

Objective To investigate the application value of MR rthrography (MRA) in the diagnosis of acetabular labral tears. Methods Fifteen patients with a high degree of suspected acetabular labral tears received fluoroscope-guided injection of the contrast media into the hip joint ( hip arthrography) and fat-saturated spin-echo T1-weighted images were obtained in the coronal, sagittal, oblique-axial and radial planes. Hip arthroscopy was performed on 12 of them. Results Labral tears which were diagnosed in 11 patients by hip MRA were confirmed at hip arthroscopy. One patient showed no MRA indication of labraltear, also showed normal on arthroscopy. Tear in the anterior-superior quadrant 10 cases of 12 joints( 12/13), posterior-superior quadrant 1 case of a joint (1/13). In 11 patients who underwent arthroscopy,hip MRA diagnosed 3 (3/13) joints labral tears in coronal planes, 10 (10/13) joints in sagittal planes and13 (13/13) labral tears in axial-oblique and radial planes. In 15 patients with 20 hip joints, 5 cases 6 joints(6/20) with normal acetabular sublabral sulcus were performed. Conclusions MR arthrography of hip is areliable method in the diagnosis of acetabular labral tears. Scanning method should be included fat-saturatedspin-echo T1-weighted images in sagittal and oblique-axial planes or sagittal plus radial planes. The diagnosisof tor posterior-inferior quadrant should pay attention to the existence of a normal variation. Key words: Acetabulum; Hip injuries; Magnetic resonance imaging; Arthrography

Development of a three-dimensional detection method of cam deformities in femoroacetabular impingement

The description of femoral head sphericity and related risk for femoroacetabularimpingement is currently limited to an angular estimate-the alpha angle-whose relevance and accuracy have been challenged. We developed a three-dimensional approach for both automated digital measurement of the alpha angle and the detection of camdeformities. Accuracy and diagnostic relevance of the alpha angle estimated by means of the oblique axial and multiple radial plane protocol were compared with the computed results. Using subject-specific statistical information of the femur head and mid-neck region, a method was developed to accurately compute the maximum alpha angle and to define aspherical eccentric areas at the femoral head-neck junction. The method was evaluated on 102 dry cadaver femur specimens. Average detection limit for bony prominences at the head-neck transition was 0.98mm. Pixel size of the investigated CT data was 0.79 mm. Mean maximum computed alpha angle of the femurs with cam-type morphology as identified by the morphological method was 67.72° (range 53.04-88.02°). Mean maximum computed alpha angle of the femurs without cam deformity was 47.65° (range 38.67-59.81°). Alpha angle estimates obtained by means of the multiple radial plane protocol correlated better (R = 0.88) and showed higher diagnostic agreement (phi = 0.77) with the 3D computational analysis compared to the oblique axial protocol (R = 0.60; phi = 0.67). The alpha angle seems to be a relevant screening tool when obtained by 3D computed analysis or when estimated according to the multiple radial plane protocol. Estimates obtained by means of the oblique axial protocol have insufficient diagnostic and measurement accuracy.

Direct Anterior Cruciate Ligament Insertion to the Femur Assessed by Histology and 3-Dimensional Volume-Rendered Computed Tomography

The purpose of this study was to histologically identify the direct and indirect insertion of the femoral anterior cruciate ligament (ACL) insertion. Furthermore, we quantitatively measured the direct femoral insertion area by use of the 3-dimensional (3D) volume-rendered (VR) computed tomography (CT) model. By use of 8 intact cadaveric knees, the lateral femoral condyle including the ACL attachment was sectioned for histologic examination in 3 oblique-axial planes parallel to the roof of the intercondylar notch and in the sagittal planes. Before sectioning, these knees had been subjected to CT to obtain 3D VR images of the femur. Once the direct insertion of the ACL was identified on each histologic section, the corresponding image was superimposed on the corresponding CT image. The direct ACL insertion, in which dense collagen fibers were connected to the bone by the fibrocartilaginous layer, was microscopically identified at the region between the posteromedial articular cartilage margin of the lateral femoral condyle and the linear bony ridge 7 to 10 mm anterior to the articular cartilage margin. Meticulous comparison of histologic analysis and the 3D VR CT model showed that the ACL direct insertion coincided with a crescent-shaped hollow just behind the linear bony ridge. The direct insertion measured 17.4 +/- 0.9 mm (mean +/- SD) in length, 8.0 +/- 0.5 mm in width, and 128.3 +/- 10.5 mm(2) in area. The direct insertion of the ACL is located in the depression between the resident's ridge and the articular cartilage margin on the lateral femoral condyle. It measured 17.4 +/- 0.9 mm in length, 8.0 +/- 0.5 mm in width, and 128.3 +/- 10.5 mm(2) in area. Delineation of the ACL femoral direct insertion by 3D VR CT could be a useful tool for planning of accurate femoral tunnel positioning in anatomic ACL reconstruction.