Imaging of a Painful

Unlock Your Hip Flexors

Unlock Your Hip Flexors

Get Instant Access

Arthur H. Newberg and Joel S. Newman

The imaging workup of the patient with hip pain should begin with plain or routine radiographs of the pelvis and hips. Certainly, by obtaining an anteroposterior view of the pelvis, as well as a lateral radiograph (true lateral, frog lateral, or Lowenstein view) one can readily compare the right and left hips, and therefore a built-in comparison is available for the radiologist and orthopedist. The diagnosis in many cases is obvious; if the patient has had recent trauma, then one evaluates the alignment of the bones. The acetabular lines should be carefully scrutinized. The addition of oblique views of the affected hip may be necessary to evaluate the anterior and posterior columns of the acetabulum. If an acetabular fracture is identified, a CT scan is suggested to assess the position of the fracture fragments and to exclude intra-articular loose bodies. The CT is often vital for operative planning. If the trauma is repetitive and a stress or fatigue fracture is being considered, radiographs must be supplemented with either a radionuclide bone scan and/or MRI. In this chapter the authors will describe the imaging characteristics of several common atraumatic and traumatic lesions, as well as discuss the more advanced techniques of MRI and MR arthrography when assessing for more localized hip joint abnormalities.

Fracture

The diagnosis of an occult hip fracture can be elusive. Often the initial radiographs are normal, especially in the elderly os-teoporotic patient. In the athlete with a suspected stress fracture, it is best to choose MRI as the first advanced imaging test. MRI can be performed rapidly, is cost effective, and is sensitive and specific for the diagnosis of occult fracture. The new high-field-strength magnets operating at 1.5 Tesla are more comfortable for the patient. The bore of the magnet is now shorter, allowing for better patient acceptance.

It has been estimated that by the year 2040, 22% of the population of the United States will be over 65 years of age, which will result in an estimated half million hip fractures per year. Establishing the diagnosis of a nondisplaced, plain filmnegative, occult hip fracture in an elderly patient can be a prolonged and costly process involving hospital admission, bed rest, and a radionuclide bone scan. Early detection of a hip fracture has increasingly important medical, economic, and legal implications in our changing health care environment.1 In the past, radionuclide imaging was the first advanced imaging technique utilized. Performed properly, scintigraphy is both sensitive and specific in the diagnosis of hip fracture.2 However, it is now clear that MRI can and should be the initial imaging modality following routine hip and pelvis radiographs, due to its high specificity and the additional clinically important information which MRI can provide. (Figure 3.1)

MRI with limited T1 weighted coronal images is 100% accurate in detecting occult hip fractures.3 Scintigraphy is sensitive but is often nonspecific and may be negative immediately after the injury or fall, especially in the elderly. When MR imaging and clinical outcome were used as the standard of reference, the prospective accuracy of MR imaging in the diagnosis of the presence or absence of hip fracture was 100%.4 A limited MRI is one way to evaluate the affected hip, however, we continue to perform a complete study in these patients because there is a high prevalence of occult pelvic fractures and soft tissue injuries identified when large-field-of-view, T1 weighted coronal sequences are combined with T2 weighted or STIR sequences. (Figure 3.2) In one study, 80% of patients referred for MRI because of suspected radiographically occult fracture had some bone or soft tissue abnormality detected with MRI.5

Hip Bone Scan Fracture

Figure 3.1. (A) Radionuclide bone scan in a 64-year-old female with right hip pain demonstrates increased uptake of the radiotracer in the intertrochanteric region of the right hip (arrow). (B) Coronal T1W1 image of the hip demonstrates a linear area of low signal extending vertically from the femoral neck laterally to the subtrochanteric area medially (arrowheads). This patient has an occult hip fracture.

Figure 3.2. (A) Coronal T1W1 of the right hip in a patient with severe pain and negative radiographs following a fall at work. There is a wavy, low-signal-intensity line indicating an occult hip fracture (arrow). (B) A coronal STIR image just posterior to the hip demonstrates high signal in the soft tissues, representing edema and hemorrhage into the posterior thigh muscles.

Figure 3.2. (A) Coronal T1W1 of the right hip in a patient with severe pain and negative radiographs following a fall at work. There is a wavy, low-signal-intensity line indicating an occult hip fracture (arrow). (B) A coronal STIR image just posterior to the hip demonstrates high signal in the soft tissues, representing edema and hemorrhage into the posterior thigh muscles.

Pictures Representing Pain Stress Fracture Hip

Stress Fracture

Stress or fatigue fracture of the femoral neck in a young patient represents abnormal stress applied to normal bone. These stresses, none of which is individually capable of producing a fracture, lead to mechanical failure over time. Stress fracture of the femoral neck tends to remain asymptomatic until advanced.

Two types of femoral neck stress fracture have been described on the basis of their precipitating strain patterns. The "compressive" variety occurs along the lower medial border, displays a sclerotic appearance on plain films, and tends not to displace.6 "Distraction" fractures along the superior portion of the femoral neck are typically radiolucent and are prone to become displaced due to tensile forces that act to pull the fracture margins apart.

MR imaging facilitates the early diagnosis of stress fracture. MR is extremely sensitive in the detection of pathophysiologic changes associated with stress injuries. Com-

pressive, medial side femoral neck fracture in these athletes often presents with bone marrow edema best shown on T2, STIR, or frequency-selective, fat-suppressed sequences. (Figure 3.3) The increased water content of the associated medullary edema or hemorrhage results in high signal intensity against the dark background of suppressed fat, such that these sequences should maximize sensitivity.

Often a low-signal fracture line will be seen in the midst of the edema. (Figure 3.4) In a compliant patient, a stress fracture of the medial or compressive side of the femoral neck can often be treated conservatively. In one study of 10 patients with femoral neck stress fracture, the bone edema seen with STIR imaging resolved in 90% of the patients within 6 months. Therefore, if high signal is seen on STIR images more than 6 months following an injury, such abnormal signal intensity is likely to represent a new injury.7 Edema resolution by MR imaging may represent an initial stage of healing, and full healing may require resolution of clinical symptoms as well.

Imaging Articulatio Femoris
Figure 3.3. (A) A 21-year-old female athlete presented with right hip pain and negative radiographs. A coronal T1W1 demonstrates an ill-defined area of low signal intensity in the right femoral neck.

Figure 3.3. (B) Coronal STIR image demonstrates bone marrow edema of the right femoral neck. In addition, along the medial femoral neck, a low signal line represents a compression side femoral neck stress fracture (arrow). (C) A follow-up radiograph demonstrates characteristic findings of a stress fracture. There is ill-defined sclerosis of the medial femoral neck (arrow).

Figure 3.3. (B) Coronal STIR image demonstrates bone marrow edema of the right femoral neck. In addition, along the medial femoral neck, a low signal line represents a compression side femoral neck stress fracture (arrow). (C) A follow-up radiograph demonstrates characteristic findings of a stress fracture. There is ill-defined sclerosis of the medial femoral neck (arrow).

Healed Femoral Head Stress Fracture Femoral Arthritis

Figure 3.4. A 32-year-old woman complained of hip pain related to vigorous daily aerobics. The upper image from an MR arthrogram of the right hip is normal. The lower image demonstrates an unsuspected stress fracture of the femoral neck (arrow).

Femoral Neck Stress Fracture Mri

Figure 3.4. A 32-year-old woman complained of hip pain related to vigorous daily aerobics. The upper image from an MR arthrogram of the right hip is normal. The lower image demonstrates an unsuspected stress fracture of the femoral neck (arrow).

Dysplasia of Hips

Hip dysplasia (DDH) refers to a developmental anomaly of the hip regardless of its etiology. The femoral head, acetabulum, or both may be dysplastic. Hip dysplasia in adults can result from multiple causes, including neuromuscular diseases, cerebral palsy, slipped capital femoral epiphysis, Legg-Calve-Perthes disease, injury, and epiphyseal dysplasia.8 The presence of hip dysplasia can result in hip pain and premature osteoarthritis. DDH is divided into three types based on the severity of the disease: Type I — hyperlaxity of the joint;

Type II — subluxable head; and Type III — dislocated hip (Figure 3.5). Subtle cases of DDH are being recognized more commonly (Figure 3.6). It is important to evaluate the slope of the acetabulum, as well as the amount of femoral head that appears uncovered by the acetabulum, and it is valuable to measure the CE angle of Wiberg. This angle is formed by measuring an angle off the vertical from the center of the femoral head to the lateral margin of the acetabulum. A normal CE angle measures greater than 25 degrees. Twenty to 25 degrees is borderline, and less than 20 degrees is diagnostic of acetabular dysplasia.8

Spinal Muscular Atrophy Hip Dislocation
Figure 3.5. Anteroposterior radiograph of the pelvis demonstrating longstanding bilateral congenital hip dislocation. Both hips have dislocated proximal to the true acetabulum and are posterior to the iliac wings.
Subtle Acetabular Dysplasia
Figure 3.6. Anteroposterior radiograph of the pelvis demonstrates subtle findings of bilateral DDH. The femoral heads are not completely covered by the acetabulum, and the CE angle measures 20 degrees.

Bone Marrow Edema Syndromes

Another unusual but very important cause of hip pain in the adult is the transient bone marrow edema (BME) pattern recognized by MR imaging.9 In many cases, this represents transient osteoporosis of the hip, an unusual but distinct syndrome characterized by self-limited pain and radiographically evident osteoporosis of the affected hip that can be distinguished from other causes of the BME pattern on the basis of clinical findings and radiographically evident focal osteopenia developing within eight weeks after the acute onset of hip pain.10 (Figure 3.7) The term transient BME syndrome can be used to describe a patient in whom a reversible bone marrow edema pattern is seen on MR images. This pattern of bone marrow edema manifests on MR images as low signal on T1 sequences. The area of abnormal signal often involves the entire femoral head, neck, and may even extend into the sub trochanteric region.11 Frequency-selective, fat-suppressed, T2 weighted sequences or STIR sequences will show very high signal in the affected areas. (Figure 3.8) Often a joint effusion accompanies this condition. Initially described in pregnant women, this entity is more common in middle aged men. Laboratory tests are normal, there is effusion of the affected hip and osteopenia of the femoral head and neck, and the ra-dionuclide bone scan shows increased uptake in the involved hip. (Figure 3.7) This entity can resolve in several months and may affect the contralateral hip at a future time. Bone marrow edema may also be seen in osteonecrosis of the femoral head. Unlike those with other causes of bone marrow edema, these patients usually have one of the well-known risk factors, such as exogenous steroid use, alcohol consumption, systemic lupus erythematosus, sickle cell anemia, or Gaucher's disease. (Figure 3.9)

Osteopenia Femoral Neck

Figure 3.7. (A) A 41-year-old man presented with acute onset of severe left hip pain. There is osteoporosis of the left femoral head and neck. (B) A radionuclide bone scan demonstrates increased uptake of the left femoral head and neck (arrow) consistent with transient osteoporosis of the hip. An MR (not shown) confirmed the diagnosis.

Figure 3.7. (A) A 41-year-old man presented with acute onset of severe left hip pain. There is osteoporosis of the left femoral head and neck. (B) A radionuclide bone scan demonstrates increased uptake of the left femoral head and neck (arrow) consistent with transient osteoporosis of the hip. An MR (not shown) confirmed the diagnosis.

Transient Osteoporosis Hip Images
Figure 3.8. (A) A 41-year-old man presented with severe right hip pain. Coronal T1W1 of the hips demonstrates diminished signal in the right femoral head and neck. (B) Coronal STIR image demonstrates dramatically increased signal in the right femoral head and neck consistent with bone marrow edema.
Positive Bony Crescent Sign Femoral Neck
Figure 3.8. (C) A follow-up coronal STIR image, 4 months later, demonstrates return of normal marrow signal in the right hip. The patient had a diagnosis of transient regional osteoporosis.
Photos Osteoporosis Left Neck

Figure 3.9. On the left, a T1W1 coronal image demonstrates low signal intensity of the femoral head. On the right, a fat-suppressed, proton density weighted coronal image demonstrates bone marrow edema of the femoral neck. There is a subchondral fracture, the crescent sign (arrows) along the superomedial femoral head. Note the joint effusion.

Figure 3.9. On the left, a T1W1 coronal image demonstrates low signal intensity of the femoral head. On the right, a fat-suppressed, proton density weighted coronal image demonstrates bone marrow edema of the femoral neck. There is a subchondral fracture, the crescent sign (arrows) along the superomedial femoral head. Note the joint effusion.

Isolated Monarticular Disease Processes

Routine hip radiographs will often be sufficient to explain a patient's symptoms. For example, soft tissue calcifications around the hip due to hydroxyapatite deposition disease suggest the diagnosis of calcific tendinitis or bursitis. (Figure 3.10)

If there is rapidly progressive narrowing of the hip joint and the symptoms are acute and severe, one must consider the diagnosis of septic arthritis. (Figure 3.11) The prompt and correct diagnosis of septic hip is essential, and the films must be evaluated carefully for evidence of joint space narrowing, osteoporosis, and loss of subchondral bone in the roof of the acetabulum, a very important sign of hip joint sepsis. (Figure 3.12) In the elderly, hip pain, limp, and deformity may be the result of Paget's disease. (Figure 3.13)

Paget Disease Femoral Head
Figure 3.10. Anteroposterior radiograph of the right hip shows linear amorphous soft tissue calcification of the joint superior to the greater trochanter within the gluteus medius tendon, characteristic of calcific tendinitis due to hydroxyapatite deposition (arrow).
Paget Disease Head
Figure 3.11. In this patient with septic arthritis, there is marked osteopenia of the right hip, loss of joint space, and loss of the well-defined subchondral bony rim of the superior acetabulum.
Septic Arthritis Hip Imaging
Figure 3.12. Radiographs of the left hip over a 5-week period demonstrating progressive joint space narrowing and loss of the normal bony subchondral dense line ("sorceil") of the superior acetabulum. This finding is suggestive of septic arthritis.
Superior Femoral Head

Figure 3.13. (A) Anteroposterior radiograph of the pelvis demonstrates Paget's disease involving the right hemipelvis. There is bony sclerosis, cortical thickening, and expansion of the bone. (B) Whole body scan demonstrates an area of intense radionuclide uptake involving a large portion of the right hemipelvis (arrow). This large contiguous area of uptake is suggestive of Paget's Disease. B

Pelvic Area Bursa

Other Localized Processes

The iliopsoas bursa is the largest normally occurring bursa in the body, and is present in 98% of adults. It generally measures 3-7 cm in length and 2-4 cm in width. When this bursa enlarges, it may enter the false pelvis via the retroperitoneum. Communication with the hip joint is demonstrated in approximately 15% of normal adults and 30-40% of patients with hip disease.12 The ilipsoas bursa may fill during a hip arthrogram, especially in patients with arthritis or total hip arthroplasty. Occasionally, an iliopsoas bursa is identified on a CT scan performed for another reason. (Figure 3.14) The less experienced image interpreter can confuse iliopsoas bursa enlargement with lymphadenopathy. In patients who develop iliopsoas bursitis, there is pain in the hip region with anterior radiation to the knee. There is point tenderness inferior to the inguinal ligament and 2 cm lateral to the femoral artery, and often a palpable mass is present.

Iliopsoas Bursitis Mri
Figure 3.14. An iliopsoas bursa is demonstrated (arrow) anterior to the left hip joint. The mass is lower in attenuation than the surrounding soft tissue structures.

Osteoid Osteoma

In young adults, osteoid osteoma of the hip can cause pain and is difficult to diagnose because intra-articular osteoid osteomas may not evoke bony sclerosis or periosteal reaction. In the appendicular skeleton, these benign tumors are usually cortical, but intracapsular osteoid osteomas are either medullary or periosteal. (Figure 3.15) In one series, 5% of these tumors were intracapsular, and the hip is one of the most common intra-articular sites. Intracapsular lesions are often difficult to identify radiographically, and the clinical picture is confusing. These lesions are associated with nonspecific symptoms, and physical examination may reveal a joint effusion synovitis, the latter histologically characterized as lym-

phofollicular. Limitation of joint motion, stiffness, weakness, flexion deformity, atrophy, contracture, and epiphyseal overgrowth have also been reported in cases of intracapsular os-teoid osteoma. The two most common radiographic findings are juxta-articular osteoporosis and widening of the medial joint space.

Thin-section CT is the best imaging technique for the identification and localization of the nidus of an osteoid os-teoma.13 CT is more accurate than MR imaging in the detection of the nidus. MR may be misleading due to the marked bone marrow edema or soft tissue mass which may accompany this lesion.14,15 (Figure 3.16) In this setting, an osteoid osteoma could be falsely mistaken for a more aggressive pathologic process.

Osteoid Osteoma Femoral Head Mri

Figure 3.15. (A) Anteroposterior radiograph of the right hip in a 14-year-old boy demonstrates an ovoid radiolucency in the medial aspect of the right femoral neck (arrow). (B) Thin-section axial CT image demonstrates an osteoid osteoma of the posteromedial right femoral neck. There is some mineralization in the center of the radiolucent nidus (arrow).

Figure 3.15. (A) Anteroposterior radiograph of the right hip in a 14-year-old boy demonstrates an ovoid radiolucency in the medial aspect of the right femoral neck (arrow). (B) Thin-section axial CT image demonstrates an osteoid osteoma of the posteromedial right femoral neck. There is some mineralization in the center of the radiolucent nidus (arrow).

Figure 3.16. (A) Coronal STIR MR image demonstrates bone marrow edema of the proximal left femur (arrow), as well as soft tissue reaction. MR did not demonstrate the nidus in this 14-year-old boy. (B) Axial CT image demonstrates the classic appearance of an osteoid osteoma. The radiolucent nidus is surrounded by minimal reactive sclerosis (arrow).

Femur Marrow

CT Hi Speed Adv SY3#HSA1 . THE B

Ex:3337 1

Se:4 RETRO OM 151.0

THE BOSTON IM

CT Hi Speed Adv SY3#HSA1 . THE B

Ex:3337 1

Se:4 RETRO OM 151.0

THE BOSTON IM

L ,

4

R

-

t v iro

. arge

3. 0mm

Tilt 0.0

1.0 s 03:

01:05

PM

:500 L •

too

Pigmented Villonodular Synovitis

Pigmented Villonodular Synovitis

Pigmented villonodular synovitis (PVNS) is a localized monarticular neoplastic process characterized by a proliferation of synovial fibroblasts and histiocytes. It usually presents in adults between the ages of 20 and 50. There is often pain, swelling, and a limp, and the hip is the second most common site affected after the knee. The lesion is characterized by either a focal nodular or diffuse pattern characterized by mult-inucleate giant cells with pigmentation due to intra- and extracellular hemosiderin deposition. The lesion is highly vascular and may invade both sides of the joint, causing well-defined erosions with sclerotic margins in both the femur and acetabulum. (Figure 3.17)

The addition of MRI has improved the diagnostic accuracy, preoperative assessment, and postoperative follow-up in these patients. MRI of the hip in these patient demonstrates characteristic foci of low signal intensity on T1 and T2 imaging sequences related to the hemosiderin deposition. These patients are treated with synovectomy. However, in the hip there may be recurrence in up to half the patients.

Old Hip Fracture Radiographics

Figure 3.17. (A) Anteroposterior radiograph of the right hip in a 34-year-old man with right hip pain. There is a lytic, destructive lesion of the right acetabulum (arrows) with preservation of the joint space. This patient has pigmented villonodular synovitis. (B) Axial CT image demonstrates a well-defined, lytic, benign-appearing lesion of the acetabulum (arrow).

Figure 3.17. (A) Anteroposterior radiograph of the right hip in a 34-year-old man with right hip pain. There is a lytic, destructive lesion of the right acetabulum (arrows) with preservation of the joint space. This patient has pigmented villonodular synovitis. (B) Axial CT image demonstrates a well-defined, lytic, benign-appearing lesion of the acetabulum (arrow).

Synovial Osteochondromatosis

This benign entity manifests as multiple small osteocartilaginous loose bodies in the hip joint. Usually these calcific densities are all of the same approximate size being either small and punctate, or pea-sized. Any patient with more than five or six loose bodies in the hip joint should be considered for having synovial osteochondromatosis. This condition repre sents a metaplasia of the synovial lining. Despite the benign nature of this condition, the myriad ossific densities within the joint capsule can cause damage to the articular surfaces if left untreated. The sheer number of these loose bodies may cause bone erosion while still preserving the joint space and the bone density of the hip. (Figure 3.18) There have been several sporadic case reports of degeneration into chondrosarcoma.

Mri Brain Arthritis
A
Synovial Osteochondromatosis Hip

Figure 3.18. (A) Anteroposterior radiograph of the hip in a 20-year-old patient with synovial osteochondromatosis. There are multiple, small osteochondral bodies in the hip joint. (B) Axial CT image demonstrates numerous intra-articular osteochondral densities. There is smooth, extrinsic erosion of the B femoral neck.

Figure 3.18. (A) Anteroposterior radiograph of the hip in a 20-year-old patient with synovial osteochondromatosis. There are multiple, small osteochondral bodies in the hip joint. (B) Axial CT image demonstrates numerous intra-articular osteochondral densities. There is smooth, extrinsic erosion of the B femoral neck.

MR Arthrography

Tears of the acetabular labrum may cause a patient disabling mechanical symptoms limiting the daily activities of individuals or the competitive participation in athletes. A labral tear may be a starting point for degenerative disease. The importance of early diagnosis and treatment of these labral abnormalities may prevent the onset of osteoarthritis and may also provide significant relief for those patients with debilitating hip pain.16 Unfortunately, tears remain an elusive clinical diagnosis. Symptoms are often vague and nonspecific. The history and findings may suggest such other etiologies as os-teoarthritis, synovitis, juxta-articular soft tissue abnormalities, osteonecrosis, or stress fracture.

Conventional MRI is limited in evaluating the labrum due to the variability in labral size and shape. Its evaluation is severely limited in most cases by the collapsed joint capsule against the acetabular rim and by the difficulty in distinguishing tears from pseudotears.17 Magnetic resonance arthrography should be reserved for the preoperative assessment of patients with chronic hip symptoms and negative results from conventional imaging studies. This procedure converts MRI from a noninvasive examination to an invasive procedure requiring an injection into the hip under fluoroscopic guidance. The principle of the procedure relies upon capsular distension, thereby outlining the labrum with contrast and filling any tears that may be present. The acetabular labrum creates a fibrocartilaginous rim that effectively deepens the hip socket and increases the surface area of the hip articulation. (Figure 3.19) The ac-etabular labrum is usually triangular but can be rounded or flattened along its free margin.17 Normal recesses occur at the junction between the labrum and the articular cartilage. It can be difficult to differentiate a labral sulcus from a true labral tear. The iliofemoral ligament is a normal structure that is one of the major hip stabilizers originating from the anterosuperior acetabular rim and then coursing inferolat-erally in the anterior hip capsule to insert onto the in-tertrochanteric ridge.

A labral tear may lead to the formation of a labral or extra-articular cyst allowing communication with the joint, and such cysts may fill with contrast after an intra-articular injection. Patients with acetabular dysplasia commonly develop labral disorders and present with symptoms that collectively are known as the acetabular rim syndrome. These patients often have recurrent episodes of groin pain. Hip dys-plasia patients are susceptible to the development of labral tears because the femoral head translocates superolaterally and impinges on the acetabular rim.17 (Figure 3.20) The articular cartilage is more difficult to evaluate in the hip than in other arthrographically studied joints, because it is difficult to get maximum capsular distension of the hip. Without the use of traction, the opposing femoral head and acetabu-lum are in tight apposition. In patients with labral tears, cartilage lesions are common and first develop adjacent to the torn labral fragment.17

Figure 3.19. Coronal T1W1 with fat suppression post intra-articular gadolinium demonstrates a normal superior acetabular labrum (arrow) and il-iofemoral ligament (white arrow).

Hip Arthrography Ddh

Figure 3.20. (A) Fluoroscopic image of a patient with DDH. There is contrast material and gadolinium in the hip joint. Note the shallow acetabulum and diminished CE angle. (B) Coronal T1 fat-suppressed image demonstrates developmental dysplasia of the hip. The femoral head is uncovered by the acetabulum.

MR Arthrography Technique

In order to avoid excessive synovial resorption of fluid, the MRI study should begin no later than 30-45 minutes following completion of the injection. Some investigators advocate instilling approximately 0.3 cc of epinephrine (1:1000) into the fluid mixture in order to slow resorption. We generally find this unnecessary. MRI arthrography may be performed with dilute gadolinium solution in sterile saline, or with saline alone. In general, gadolinium MRI is preferable by virtue of the fact that the injected fluid is bright on T1 weighted images, allowing differentiation from noncommunicating cysts, bursae, and other preexisting extra-articular fluid collections.

With the patient in the supine position on the fluoroscopy table, the hip joint is localized. The hip is maintained in neutral position, the puncture site is selected, the overlying skin is marked and cleansed with an iodine solution, and sterile drapes applied. Superficial and deep local anesthetic (1% Li-docaine mixed with sodium bicarbonate) is infiltrated along the expected needle course. The anterior joint capsule extends down to the trochanteric ridge. In order to avoid the femoral vessels, the capsule is punctured overlying the outer half of the femoral neck. In many cases, a needle course directly perpendicular to the skin is possible. With some patients, particularly if obese, an oblique approach from a more laterally positioned skin entry site is necessary.

A 9 cm, 20 gauge spinal needle is advanced down to the cortical surface of the femoral neck, and intracapsular location is confirmed with the injection of 2 cc of iodinated, non-ionic contrast material. Approximately 8 cc of a very dilute solution of gadolinium in nonbacteriostatic sterile saline (1:150-1:200) is then instilled into the hip joint. The procedure is performed under direct fluoroscopic control in order to assure that there is no inadvertent extracapsular injection. A spot radiograph is obtained at the completion of the procedure, documenting intracapsular contrast material. The patient is then transferred to the MRI scanner. In order to optimize detail, a small phased-array coil is placed directly over the symptomatic hip. Imaging is performed in the coronal, sagittal, oblique sagittal, and axial planes. The oblique sagittal plane is of particular value in evaluating the anterior ac-etabular labrum. This sequence is obtained in an axis roughly parallel to the superior labrum and lateral femoral neck. (Figure 3.21) On fat-saturated, T1-weighted images, the gadolinium solution will be intensely bright while the adjacent soft tissue signal will be suppressed. This heightens the con-spicuity of labral tears. Extracapsular fluid collections, including noncommunicating bursitis as well as soft tissue and bone marrow edema, muscle injury, etc will not be visible on the T1 weighted, fat-suppressed images. Therefore, at least one proton density or T2 weighted sequence is necessary in order to identify bone and extracapsular soft tissue pathology.

Imaging Planes Mri Arthrogram Hip
Figure 3.21. This scout view of the hip demonstrates the image plane for the oblique sagittal sequence. Imaging along this plane best shows the acetabular labrum.

On MR arthrography, labral tears manifest as an abnormal, linear extension of high-signal-intensity gadolinium solution into the labrum, labral blunting, or detachment of the labrum from the underlying bone. (Figures 3.22 and 3.23) Paralabral cysts may accompany labral tears. The normal labrum has a uniform, very low signal intensity, appearing black on MRI. (Figure 3.24) With labral degeneration, there is abnormal intermediate (gray) signal within the labrum, but labral contours are preserved, and there is no imbibing of gadolinium into the substance of the labrum. (Figure 3.25) Normal hyaline cartilage manifests intermediate to bright signal on MRI, although typically less intense than that of gadolinium solution. The articular cartilage should be carefully evaluated on all imaging planes. The gadolinium solution will outline the articular margins, defining any cartilage defects. (Figure 3.26) Other features of osteoarthritis, such as subchondral cysts, will also be depicted. Osteochondral bodies are represented by low-signal-intensity filling defects within the gadolinium solution. (Figures 3.27 and 3.28)

The ultimate value of MRI arthrography will depend on the success and accuracy of hip arthroscopy and its use as a treatment modality to alleviate the patient's signs and symptoms. Presumably, early detection and treatment of labral abnormalities might also delay the onset of osteoarthritis. Although many patients with acetabular labral tears, chondral flaps, or loose bodies experience improvement following arthroscopic treatment, the long-term benefits of this treatment modality have not yet been proven.

Figure 3.22. Sagittal T1 weighted, fat-suppressed image from a gadolinium MR arthrogram demonstrates a large tear of the anterior labrum. (arrow) In addition, there are degenerative changes of the hip joint.

Evaluating Mri Arthrogram

Figure 3.22. Sagittal T1 weighted, fat-suppressed image from a gadolinium MR arthrogram demonstrates a large tear of the anterior labrum. (arrow) In addition, there are degenerative changes of the hip joint.

Torn Labrum Healthy Labrum Mri
Figure 3.23. Oblique sagittal T1W1 with fat suppression demonstrates a torn anterior labrum (arrow). Note a normal posterior labrum (arrowhead).
Enlarged Iliopsoas Bursa
Figure 3.24. Axial T1W1 with fat suppression post instillation of gadolinium demonstrates normal anterior and posterior labrum (curved arrows). The contrast material enters a communicating iliopsoas bursa (straight arrow).
Small Femoral Head Osteophytes

Figure 3.25. Coronal fat-suppressed T1W1 post intra-articular gadolinium administration demonstrates an enlarged, swollen, degenerated superior labrum (arrow) characterized by abnormal signal and morphology of the labrum. Gadolinium has been imbibed into the labral substance.

Acetabular Labral Thickening

Figure 3.26. Coronal fat-suppressed image from a MR arthrogram demonstrates loss of femoral head and acetabulum articular cartilage (arrows). A small osteophyte is seen on the superolateral femoral head.

Detached Osteophyte Hip

Figure 3.27. (A) Anteroposterior radiograph of the left hip demonstrates a loose body (arrow), as well as early degenerative change of the femoral head. (B) Axial T1 weighted, fat-suppressed image with gadolinium in the left hip joint demonstrates a loose body (arrow) in the posterior aspect of the joint. Several other loose bodies were identified on other images.

Small Femoral Head Osteophytes Synovial Osteochondromatosis Left Hip

Figure 3.28. Coronal fat-suppressed T1W1 post gadolinium demonstrates a distended left hip joint capsule with multiple filling defects (arrows) in a patient with synovial osteochondromatosis.

Mri Arthrogram Hip Joint

Figure 3.28. Coronal fat-suppressed T1W1 post gadolinium demonstrates a distended left hip joint capsule with multiple filling defects (arrows) in a patient with synovial osteochondromatosis.

References

1. May D, et al. MR imaging of occult traumatic fracture and muscular injuries of the hip and pelvis in elderly patients. AJR 1996; 166:1075-1078.

2. Holder LE, Schwarz C, Wernicke PG, Michael RH. Radionuclide imaging in the early detection of fractures of the proximal femur. Radiology 1990;174:509-515.

3. Quinn S, McCarthy J. Prospective evaluation of patients with suspected hip fracture and indeterminate radiographs: Use of T1 weighted MR images. Radiology 1993;187:469-471.

4. Deutsch A, Mink L, et al. Occult fractures of the proximal femur: MR imaging. Radiology 1989;170:113-116.

5. Bogost G, et al. MR imaging in evaluation of suspected hip fracture: Frequency of unsuspected bone and ST injury. Radiology 1975;197:263-267.

6. Anderson MW, Greenspan A. Stress fractures. Radiology, 1996; 199:1-12.

7. Slocum K, et al. Resolution of abnormal MR signal intensity in patients with stress fractures of the femoral neck. AJR 1997;168: 1295-1299.

8. Delaunay S, et al. Radiographic measurements of dysplastic adult hips. Skel Rad 1997;26:75-81.

9. Hayes CW, Conway WF, Daniel WW. MR imaging of bone marrow edema pattern: Transient osteoporosis, transient bone marrow edema syndrome or osteonecrosis. Radiographics 1993;13:1001-1011.

10. Wilson A, et al. Transient osteoporosis: Transient bone marrow edema? Radiology 1988;167:757-760.

11. Bloehm J. Transient osteoporosis of the hip: MR imaging. Radiology 1988;167:753-755.

12. Sartoris DJ, Danzig L, Gilula L. Greenway G, Resnick D. Synovial cysts of the hip joint and iliopsoas bursitis: A spectrum of imaging abnormalities. Skel Rad 1985;14:85-94.

13. Assoun J, et al. Osteoid osteoma: MR imaging versus CT. Radiology 1994;191:217-223.

14. Woods ER, et al. Reactive soft tissue mass associated with os-teoid osteoma: Correlation of MR imaging versus CT. Radiology 1993;186:221-225.

15. Biebuyck JC, Katz L, McCaukley T. Soft tissue edema in os-teoid osteoma. Skel Rad 1993;22:37-41.

16. Haims A, Katz LD, Busconi B. MR Arthrography of the hip. Rad Clin N Am 1998;36:691-702.

17. Palmer WE. MR Arthrography of the hip. Sem Musculoskel Radiol 1998;2:349-361.

This page intentionally left blank

Was this article helpful?

0 0
Treating Rheumatoid Arthritis With Herbs Spices Roots

Treating Rheumatoid Arthritis With Herbs Spices Roots

Did You Know That Herbs and Spices Have Been Used to Treat Rheumatoid Arthritis Successfully for Thousands of Years Do you suffer with rheumatoid arthritis Would you like to know which herbs and spices naturally reduce inflammation and pain 'Treating Rheumatoid Arthritis with Herbs, Spices and Roots' is a short report which shows you where to start.

Get My Free Ebook


Responses

  • BERTHA
    What is the linear soft tissue calcification at the right trochanter?
    7 years ago
  • Aaron
    What its the bright white mean in an arthrogram?
    7 years ago
  • edward
    What are soft tissue masses on hips?
    7 years ago
  • martha
    What does small area of fluid signal in the left anterior femoral head neck mean?
    7 years ago
  • sarah
    What will a MRI of the hip and upper thigh show?
    7 years ago
  • finley
    What does vertebral arteries abnormal signal intensity on a mr of the neckmean?
    5 years ago
  • michael müller
    What is subchondral bone blunting?
    5 years ago
  • niamh
    What does degenerative type blunting on hip mri mean?
    4 years ago
  • Sean
    What is an ill defuned lesion in thr right superior acetabulum?
    4 years ago
  • Rina
    What does a cyst of anterior aspect of the right femoral head mean?
    4 years ago
  • Janice
    What does Increased radiotracer uptake in the region of the left hip Bone scan mean?
    4 years ago
  • brooklyn
    What does 1.5 cm calcific density adjacent to the superolateral acetabulum mean.?
    4 years ago
  • Maija
    What does signal abnormality of femoral head and neck mean?
    4 years ago
  • Ciro
    What does uptake in femur area mean in?
    4 years ago
  • marko
    Does abnormal activities on femoral head, neck and intertrochanteric means bone tumor ?
    4 years ago
  • Rosa
    Can longstanding hip arthritis cause calcification in surroundig muscles and tendons?
    4 years ago
  • ULRIKE
    Does the bursa on a t1 mr arthrogram gadolinium show dark or bright?
    3 years ago
  • GENET
    Is calcifaction painful on femoral head?
    3 years ago
  • Pamphila
    Where is the medial aspect of femoral neck?
    3 years ago
  • Ferdinand
    What are tiny erosions in left femoral neck?
    3 years ago
  • tanja
    What does degenerative type uptake from a bone scan mean?
    3 years ago
  • anke
    What is femoral head bone density?
    3 years ago
  • juan
    What does photopenia involving femoral head mean?
    3 years ago
  • Ennio Siciliani
    Is bone marrow edema painful?
    2 years ago
  • Demsas
    What does "the bilateral femoral heads are overlying the bilateral acetabulum" mean?
    2 years ago
  • aino
    How femoral neck could have small bony?
    2 years ago
  • Marcel
    Can bone mineralization indicate a stress fracture in femur?
    2 years ago
  • BALDASSARRE
    What is edema in the hip femoral head?
    2 years ago
  • Athos
    What is marginated ossific density of the superolateral acetabulum?
    2 years ago
  • Christine Eberhart
    What is subtle marrow signal abnormality in acetabulum?
    2 years ago
  • KERSTIN
    What does sclerotic lesions and femoral heads consistant wih avn mean?
    2 years ago
  • KACI
    What is attentuation and blunting on mri?
    2 years ago
  • David Hahn
    What does total loss of superolateral aspect of the hip mean?
    2 years ago
  • cora
    What is a curvilinear nodule along the femoral head mean?
    2 years ago
  • bethany
    What does marrow edema in the left acetabulum mean?
    2 years ago
  • Nibs
    What is meant by arthritic growths in the femur?
    1 year ago
  • Saba
    What does moderate osteophytes in the femoral and acetabulum mean?
    1 year ago
  • ANNA SCHWARTZ
    What is ovoid density in femoral neck?
    1 year ago
  • cohen forbes
    What causes benign cyst at femoral head?
    1 year ago
  • pertti
    What is the lateral aspect of the femoral head?
    12 months ago
  • Concordia
    What does prominence of the lateral femoral heard margin mean?
    11 months ago
  • efrem
    What is bossing at the superolateral aspect of the femoral head?
    10 months ago
  • lemlem
    What is joint space widths are preserved mean?
    9 months ago
  • berylla
    What does it mean when you have t2 intensity in the femoral head in my hip?
    8 months ago
  • saba
    What is diffuse signal alteration involving the left femoral head?
    8 months ago
  • MAXINE GONZALES
    What is a lobular lesion within left fermiral pelvic hesd/neck?
    7 months ago
  • Ermes
    What does flattening of the femur mean?
    6 months ago
  • GILDA LORENZO
    What does this mean calcification lateral to acetabulum?
    6 months ago
  • Jona
    What is sclerosis of the femoral head?
    6 months ago
  • jaden
    What is the white color around the hip joint labrum on mri?
    4 months ago
  • Ali
    What is foci in a hip MRI?
    4 months ago
  • Hugo
    What does Bone scan demonstrated evidence of increased signal noted around the femoral prosthesis?
    3 months ago
  • Violet
    What is flattening of the superior left femoral head and superior acetabulum?
    3 months ago
  • amethyst
    What codition increases calcification around femoral neck?
    2 months ago
  • Debra
    What does it mean if there is a linear signal in the subchondral fibular head?
    2 months ago
  • tom kauppinen
    What will a femoral mri show?
    25 days ago
  • Luisella
    What is subcortical high signal on posterosuperior femoral head?
    4 days ago

Post a comment