Radiographs Pelvis

Repeated exposure to excessive concentrations of hydrogen fluoride over a period of years may result in an increased radiographic density of bone and eventually may cause crippling fluorosis (osteosclerosis due to deposition of fluoride in bone)/ The early signs of increased bone density from fluoride deposition are most apparent in the lumbar spine and pelvis and can be detected by X ray. 

Radiographic imaging studies evaluate the extent of disease involvement. A chest x-ray should be performed to rule out the presence of metastatic spread to the lungs. A CT scan of the abdomen and pelvis is often performed to evaluate hepatic and retroperitoneal involvement and occult abdominal and pelvic disease, and to determine the depth of tumor penetration into the bowel wall and/or invasion to adjacent organs. Detection of lymph node involvement with either smdy is limited by the difficulty of distinguishing inflammatory or reactive lymph nodes from those infiltrated with tumor. Because CT scans may not adequately detect peritoneal seeding, small distant lymph node metastasis, or liver metastasis in colon cancer, an occasional patient may... 

Sahdev A, Jones J, Shepherd JH, Reznek RH (2005) MR imaging appearances of the female pelvis after trachelec-tomy. Radiographics 25 41-52... 

Foshager MC, Walsh JW (1994) CT anatomy of the female pelvis a second look. RadioGraphics 14 51-66... 

Umeoka S, Koyama T, Togashi K et al (2004) Vascular dilatation in the pelvis identification with CT and MR imaging. Radiographics 24 193-208... 

Pereira JM, Sirlin CB, Pinto P et al (2005) CT and MR imaging of extrahepatic fatty masses of the abdomen and pelvis techniques, diagnosis, differential diagnosis and pitfalls. Radiographics 25 69-85... 

In the acute situation, the speed of a CT examination and the ease with which it can be obtained, mean CT is the imaging modality of choice in cases of polytrauma. In some institutions, radiographs of the chest and pelvis are no longer obtained, if it is known the patient is due in CT (Chapman et al. 2005 Salamipour et al. 2005). 

The AP radiograph should be closely reviewed for signs of pelvic ring discontinuity by identifying various anatomical lines, the absence of which implies ring disruption or a fracture. These lines are the ischio-ilial line, ilio-pectineal line, and the anterior and posterior acetabular walls. The ilio-ischial line is formed by the posterior structures of the pelvis and the ilio-pectineal by the anterior acetabular structures (Ersoy et al. 1995) (Fig. 12.3). 

This is usually the result of forces transmitted through the axial skeleton from an impact into the head and shoulders through to the lower limbs. There may be symphyseal diastasis, anterior arch fractures or posterior disruption of the sacroiliac joints with cephalic displacement. Vertical injuries are often severe with disruption of all the ligaments plus associated pelvic instability. Radiographs demonstrate ipsilateral or contralateral pubic rami fractures, with disruption of the sacroiliac joint. The major differentiating feature from compression injuries is the cephalic displacement of the pelvis on the side of the impact (Fig. 12.14). 

The anterior column corresponds to the ili-opectineal line on an AP radiograph and the posterior column the ilioischial line. Judet views allow more detailed examination of the acetabular columns, although these have largely been super-ceded by CT examination. The internal (obturator) oblique view is taken with the pelvis rotated anteriorly by 45° and shows the iliopectineal line and posterior wall of the acetabulum, but again CT is more useful and allows multiplanar reconstructions. 

The primary imaging assessment of the paediatric hip typically involves an AP radiograph of the pelvis. If it is the first presentation then lateral views are indicated. Initial trauma films should be taken without gonad protection, as this may obscure fractures. If the child is being followed up and the pathology is... 

Fig. 13.4a,b. AP and frog lateral radiographs of the pelvis in a child with slipped capital femoral epiphysis... 

Fig. 13.5. a AP radiograph of the pelvis of a 14-year-old boy with left slipped capital femoral epiphysis, b The features of the normal right hip are emphasised on the same radiograph. A line drawn along the femoral neck intersects the epiphysis (Klein s line), and a dense triangle of bone is seen where the metaphysis of the hip overlies the acetabulum. These features are not seen on the abnormal left side, c The frog leg lateral radiograph of the same patient clearly shows the left slipped epiphysis... 

An example of a radiograph from a short-term implanted PTFE low friction arthroplasty is shown in Figure 4.4. This radiograph shows the initial orientation of the PTFE cup with respect to the pelvis. Initially, the femoral head is centered in the acetabular cup. 

Wear of conventional UHMWPE has historically been recognized as the primary culprit responsible for inflammatory bone loss and late revision of hip replacements. Researchers have estimated that for each day of patient activity, around 100 million microscopic UHMWPE wear particles are released into the tissues surrounding the hip joint [19]. This particulate wear debris can initiate a cascade of adverse tissue response leading to osteolysis (bone death) and ultimately aseptic loosening of the components [20-23]. The radiograph in Figure 5.3 (provided courtesy of Av Edidin, PhD, Drexel University) shows an example of an osteolytic lesion in the pelvis located superior to the historical, gamma-sterilized acetabular component... 

Based on a review of the literature, Dumbleton et al. [24] suggest that radiographic wear rates of less than 0.05 mm/y are below an osteolysis threshold below which patients are not expected to be at risk of developing osteolysis. Osteolysis, in turn, may be associated with the need for revision, depending upon the location (i.e., in the pelvis or femur) and rate of progression. As noted by Hozack et al. [25] ... 

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