A new tilt on pelvic radiographs: a pilot study

Richards, Paula J.; Pattison, J.; Belcher, John; DeCann, R W; Anderson, Suzanne E.; Wynn-Jones, C.

doi:10.1007/s00256-008-0481-0

Cited by 16 publications

(16 citation statements)

References 25 publications

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“…Several prior studies have reported on the difficulty and variability of predicting FAI based on AP radiographs [9,12,17,20,22] and this CT computational method might potentially reduce those errors. Using our methodology, it is possible not only to correct pelvic alignment, but also to simply define the acetabular rim.…”

Section: Discussionmentioning

confidence: 99%

“…A common radiographic finding related to focal acetabular overcoverage is referred to as the crossover sign (figure-of-eight) and exists when the lateral projection of the anterior wall crosses the posterior wall of the acetabular rim [11]. However, the degree of pelvic tilt and rotation changes the amount (or apparent existence) of crossover in patients, making it difficult to quantify on AP radiographs alone [9,12,17,20,22]. Moreover, the xray beam divergence in AP pelvis radiographs produces an overestimation of acetabular version by 4° [9].…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the xray beam divergence in AP pelvis radiographs produces an overestimation of acetabular version by 4° [9]. Furthermore, defining the anterior and posterior rims on AP radiographs can be difficult [12]. Several methods [3,17,23] have been proposed to eliminate the effect of pelvic tilt on the appearance of the crossover sign.…”

Section: Introductionmentioning

confidence: 99%

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A Quantitative Method to Assess Focal Acetabular Overcoverage Resulting From Pincer Deformity Using CT Data

Murphy

Subhawong

Chhabra

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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Background Current assessment techniques for focal acetabular overcoverage are neither consistent nor quantitatively accurate. Questions/purposes We propose: (1) a method to precisely quantify the amount of focal acetabular overcoverage in a patient's pincer deformity based on CT data; (2) to evaluate the consistency of this method; and (3) to compare the method with conventional radiographic assessments.Methods We developed a method to assess focal acetabular overcoverage using points selected from CT scans along the acetabular rim after realigning the pelvis into a neutral position. Using four resampled and segmented pelvic CT scans of cadaveric specimens with virtually induced impingement, two observers independently tested the algorithm's consistency. Our algorithm assessed the amount of focal acetabular overcoverage using CT data and projected data from reconstructed radiographs. Results (1) We successfully showed the feasibility of the software to produce consistent, quantitative measurements. (2) Testing showed the average difference between observers in aligning the pelvis was 0.42°, indicative of a consistent approach. (3) Differences between measurements on three-dimensional (3-D) CT and simulated radiographs were significant. Conclusions The proposed method represents a new avenue in consistently quantifying focal acetabular overcoverage using CT models while correcting for pelvic tilt and rotation. Our analysis confirms AP hip radiograph simulations overestimate the amount of overhanging acetabular rim in a pincer deformity. Clinical Relevance This technique has potential to improve preoperative diagnostic accuracy and enhance surgical planning for correction of a pincer deformity resulting from focal acetabular overcoverage.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Quantitative Method to Assess Focal Acetabular Overcoverage Resulting From Pincer Deformity Using CT Data

Murphy

Subhawong

Chhabra

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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“…This should measure at least 1 mm in girls and at least 3 mm in boys [ 100 ]. CT or MRI can supply more accurate measurements [ 101 ].…”

Section: Imagingmentioning

confidence: 99%

The Pelvis and Hip: Congenital and Developmental Conditions

Grissom

2014

Pediatric Orthopedic Imaging

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The chapter begins with a section on the normal development of the pelvis, acetabulum, and femoral neck, head, and epiphysis. Discussion of congenital and developmental abnormalities follows. Proximal focal femoral defi ciency is described fi rst. This is followed by a discussion of both intrauterine hip dislocation and a lengthy discussion of developmental dysplasia of the hip (DDH). Within this section, many different imaging techniques are broken down, the treatment of DDH by osteotomies is discussed, and postoperative complications as well as differential diagnosis are explained. Sections on coxa vara and acetabular protrusion follow. Femoral head dysplasia is broken down into both localized and generalized disorders: microepiphyseal dysplasia, Meyer dysplasia, osteochondritis dissecans-like femoral head dysplasia, multiple epiphyseal dysplasia, and epiphyseal dysgenesis in hypothyroidism.

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“…hip dysplasia [10], [11]. To detect and quantify congenital or acquired hip dysplasia, especially when the treatment includes surgical intervention, the anterior and posterior acetabular sector angles (AASA and PASA, respectively), center-edge angle (CE), vertical-center-anterior angle (VCA) and acetabular index of depth to width (D/W) are usually evaluated [10,[12][13][14]. The angles serve to estimate alignment of the femoral head to the acetabulum, i.e.…”

Section: Introductionmentioning

confidence: 99%

Automated measurement of anterior and posterior acetabular sector angles

et al. 2012

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In this paper, we propose a segmentation algorithm by which anatomical landmarks on the pelvis are extracted from computed tomography (CT) images. The landmarks are used to automatically define the anterior (AASA) and posterior acetabular sector angles (PASA) describing the degree of hip misalignment. The center of each femoral head is obtained by searching for the point at which most intensity gradient vectors defined at edge points intersect. The radius of each femoral head is computed by finding the sphere, positioned at the center of the femoral head, for which the normalized sum of gradient vector magnitudes on the sphere surface is maximal. The anterior and posterior corners of each acetabulum are searched for on a curve representing the acetabulum and defined by dynamic programming. The femoral head centers and anterior and posterior corners are used to calculate the AASA and PASA. The algorithm was applied to CT images of 120 normal subjects and the results were compared to ground truth values obtained by manual segmentation. The mean absolute difference (± standard deviation) between the obtained and ground truth values was 1.3 ± 0.3 mm for the femoral head centers and 2.1 ± 1.3 degrees for the acetabular angles.

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A new tilt on pelvic radiographs: a pilot study

Cited by 16 publications

References 25 publications

A Quantitative Method to Assess Focal Acetabular Overcoverage Resulting From Pincer Deformity Using CT Data

A Quantitative Method to Assess Focal Acetabular Overcoverage Resulting From Pincer Deformity Using CT Data

The Pelvis and Hip: Congenital and Developmental Conditions

Automated measurement of anterior and posterior acetabular sector angles

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