Gregorys Test

Giufeng, Ajay, Joey, and Paul sit around enjoying cup of coffee with some cookies as their day draws to an end. Suddenly Hannah turns around the corner: "You have got to have a look at this," she smiles at them. "Segner is just now taking Gregory apart for good. Greg is all excited and tense." "We should go listen, perhaps we can learn a thing or two," suggests Joey. "Oh, for heaven's sake, why don't you leave them alone. Gregory probably wouldn't appreciate a crowd right now," says Giufeng. "Now, there is a good reason!" Paul grins, and moves to the door together with Joey. "Let's move, mates!"

"This could have gone all wrong and it still may, Gregory," shouts Segner as our students turn the corner. Gregory crouches on the procedure table, his scrubs clinging to his chest like a wet mop. Segner ignores the interns' arrival and continues his yelling sermon with swollen neck veins. "If you do an elective intervention you cannot brief the patient on the table, dammit! When and where must this happen? And then you did not check the clotting! Just how stupid can one be! Which parameters do you need to know and what are the minimum or maximum levels? And then you had someone inexperienced compress the puncture site—Gregory, you must have had a blackout! Don't tell me about a long intervention! Let me tell you what a long intervention is. You'd better pray that inguinal hematoma does not get larger or get infected. The guys in intensive care will laugh their heads off. Listen, Greg, this is my outfit and this is radiology, not cardiology. You'd better get your act together before you touch another catheter in this department." Segner storms out the door. Gregory takes a deep breath and remains silent—of course he knows that Segner is right. Giufeng pushes the others out of the room "Get lost now, all of you!" she says and returns into the dark room closing the door behind her. Gregory was pretty careless. Giufeng knows why: he learned today that one of his articles has been accepted for publication in Radiology. He was absolutely out of it. The hype did not do him any good. Can you help Gregory with the answers to Segner's questions?

Clinical Test

Imaging of skeleton and soft tissues is the cradle of radiology. Here the technology had the greatest therapeutic impact in the early decades. Even today seasoned radiologists are faced with major challenges in this field and must prove their mastery. They share this interest with a sizable number of clinical specialists from other fields with whom—in their own and the patient's best interest—they must be competent partners. Decades of experience, a strong interest in the science behind imaging phenomena, a substantial library—the most voluminous book on the subject fills about 5000 pages in small print—and an inexhaustible passion for the great interesting case make up a real "bone radiologist." It is thus nothing to turn into overnight. Students and young colleagues need to constantly search for and learn the key findings to improve their skill in this field. A sound knowledge of the proper clinical indications for the available imaging modalities is a good start (Table 8.1).

Table 8.1 Suggestions for diagnostic modalities in musculoskeletal imaging1

Clinical problem

Modality

Comment

Bone pain

XR

Gross assessment of symptomatic areas.

NM

Bone scan indicated if symptoms persist and plain XRs are negative. Shows number of lesions.

MRI

Appropriate if symptoms persist and conventional XR and NM fail to diagnose disease.

Suspected primary bone tumor

XR

May help to characterize the lesion; sufficient in many cases; should be carried out when bone pain does not resolve. If XR is suggestive of primary bone tumor, referral to a specialized center is advised.

MRI MRI

Useful for further characterization and necessary for local staging; should be performed before any biopsy.

Can show bony detail better at some sites (e.g., spine) and helps analyze internal matrix in some tumors (e.g., osteoid osteoma); easily demonstrates calcification/ossification. Chest CT if CXR is negative to assess pulmonary metastases for many primary malignant lesions. CT-guided biopsy should be carried out in specialized bone tumor centers.

Initial modality of choice, can be normal for first 2-3 weeks.

NM

Two- or three-phase skeletal scintigram is more sensitive than XR but nonspecific. Labeled white cell scintigraphy may distinguish infection from other lesions.

MRI

Accurately demonstrates infection, especially in the spine.

CT

Used to identify bony sequestrum.

Known primary tumor/suspected MRI Primary modality of choice. More sensitive and specific than NM, especially skeletal metastases for marrow-based lesions and in the axial skeleton. May underestimate number of peripheral lesions.

CT, computed tomography; DXA, dual-energy x-ray-absorptiometry; MRI, magnetic resonance imaging; NM, nuclear medicine; US, ultrasound; XR, radiography.

Table 8.1 Suggestions for diagnostic modalities in musculoskeletal imaging1 (Continued)

Clinical problem

Modality

Comment

XR

Only for specific focal symptomatic areas; correlation with positive NM (exclusion of degenerative disease) and to determine stability.

NM

Sensitive test but correlative imaging is needed to increase specificity. Useful for overall assessment for skeletal metastases as long as the tumor causes sufficient local bone turnover to become detectable.

Suspected myeloma

XR skeletal survey

For staging and identifying lesions that may benefit from radiotherapy. Survey of limited value for follow-up and to assess response to therapy.

MRI

Very sensitive, even when limited to spine, pelvis, and proximal femora. Particularly useful in nonsecretory myeloma or in the presence of diffuse osteopenia. Can be used for tumor mass assessment and follow-up under therapy.

NM

Insensitive test in myeloma.

Osteomalacia

XR

To establish cause of local pain or equivocal lesion on NM.

NM

Skeletal scintigraphy can show increased activity and some local complications such as pseudofractures. Bone densitometry may be needed.

Metabolic bone disease

XR

May be helpful to differentiate new from old vertebral fractures or to identify different causes of pain. Correlation with NM will be required.

NM

Skeletal scintigraphy may be useful for differentiating causes of hypercalcemia (metastases, hyperparathyroidism) and of raised alkaline phosphatase (Paget disease).

DXA

DXA or quantitative CT quantifies bone mineral content.

Arthropathy, presentation

XR affected joint

May be helpful to determine cause, although erosions are a relatively late feature.

XR hands/ feet

In patients with suspected rheumatoid arthritis, XR of feet may show erosions even when symptomatic hands appear normal.

US or NM or MRI

All accurately show acute synovitis. NM can show distribution. MRI can assess articular cartilage and early erosions.

Arthropathy, follow-up

XR

Needed by rheumatologists to assist management decisions.

Hallux valgus

XR

For assessment before surgery.

Spinal problems

Pain, suspected osteoporotic collapse

XR

Lateral views will demonstrate compression fractures. NM or bone densitometry (DXA or quantitative CT) provide objective measurements of bone mineral content; can also be used for metabolic bone disease.

MRI

More useful in distinguishing between recent and old fractures and can help exclude pathological fractures. Excellent modality to assess for extraosseous soft tissue mass in pathological fractures.

Cervical spine

Neck pain, arm pain, suspected degenerative change

XR

Neck pain generally improves or resolves with conservative treatment. Degenerative changes begin in early middle age and are often unrelated to symptoms.

CT, computed tomography; DXA, dual-energy x-ray-absorptiometry; MRI, magnetic resonance imaging; NM, nuclear medicine; US, ultrasound; XR, radiography.

Suggestions for diagnostic modalities in musculoskeletal imaging

Table 8.1 Suggestions for diagnostic modalities in musculoskeletal imaging1 (Continued)

Clinical problem

Modality

Comment

MRI Consider MR and specialist referral when pain affects lifestyle or when there are neurological signs. Myelography (with CT) may occasionally be required to provide further delineation or when MRI is unavailable or impossible to obtain.

Thoracic spine

Pain without trauma: suspected degenerative change

XR

Degenerative changes are invariable from middle age onward. Imaging is rarely useful in the absence of neurological signs or pointers to metastases or infection. Consider more urgent referral in elderly patients with sudden pain to show osteoporotic collapse or other forms of bone destruction. Consider NM for possible metastatic lesions.

MRI

May be indicated if local pain persists or is difficult to manage or if there are long tract signs.

Lumbar spine

Chronic back pain with no pointers to infection or neoplasm

XR

Degenerative changes are common and nonspecific. Main value in younger patients (e.g., less than 20 years), spondylolisthesis, ankylosing spondylitis, etc., or in older patients >55. In cases where management is difficult, negative findings may be helpful.

MRI

First-choice method when symptoms persist or are severe or where management is difficult. Imaging findings are to be interpreted with caution because abnormalities are frequent and not necessarily related to clinical signs. Negative findings may be helpful.

Back pain with possible serious features such as:

■ Sphincter or gait disturbance

■ Saddle anesthesia

■ Severe or progressive motor loss

■ Widespread neurological deficit

■ Previous carcinoma

■ Systemic illness

■ Intravenous drug abuse

■ Structural deformity

■ Nonmechanical pain

MRI

Together with urgent specialist referral, MRI is usually the best modality. Imaging should not delay specialist referral. NM is also widely used for possible bone destruction, and in cases of chronic pain or where infection is suspected.

XR

"Normal" plain XR may be falsely reassuring but XR should be done to exclude spondylolisthesis or spondylolysis.

Acute back pain:

suspected disk herniation; sciatica with no adverse features

XR

Acute back pain usually due to conditions that cannot be diagnosed on plain XR (osteoporotic collapse and spondylolisthesis are the exception). "Normal" plain XRs may be falsely reassuring.

MR or CT

Imaging disk herniation requires MRI or CT: MR is generally preferred. Correlation of clinical and imaging findings is important as a significant number of disk herniations are asymptomatic. Either MR or CT is needed before intervention (e.g., epidural injection). MRI is better than CT for postoperative problems.

CT, computed tomography; DXA, dual-energy x-ray-absorptiometry; MRI, magnetic resonance imaging; NM, nuclear medicine; US, ultrasound; XR, radiography.

Table 8.1 Suggestions for diagnostic modalities in musculoskeletal imaging1 (Continued)

Clinical problem

Modality

Comment

Shoulder problems

Painful shoulder

XR

Not indicated initially. Degenerative changes in the acromioclavicular joints and rotator cuff are common.

Shoulder impingement

MRI

Although impingement is a clinical diagnosis, imaging is indicated when surgery is being considered and precise delineation of anatomy is required. Degenerative changes are also common in the asymptomatic population.

US

Subacromial and acromioclavicular joint impingement are dynamic processes that can be assessed by US.

Shoulder instability

CT/MRI arthrography

Glenoid labrum and joint space are well delineated by both techniques. Some gradient echo MR techniques can show the labrum well without arthrography. Arthrography (with or without CT), US, and MRI may all be used in the diagnosis.

Rotator cuff tear

Arthrography, US, or MRI

MRI provides the best global assessment and has highest accuracy when combined with arthrography.

Knee problems

Knee pain: without locking or restriction in movement

XR

Symptoms frequently arise from internal derangement of ligamentous or cartilaginous structures and these will not be demonstrated on XR. Osteoarthritic changes are common. XRs needed when considering surgery.

Knee pain: with locking, restricted movement or effusion (loose body)

XR

To identify radiopaque loose bodies.

Knee pain: arthroscopy being considered

MRI

Can assist the management decision whether to proceed with arthroscopy. Even in those patients with definite clinical abnormalities, warranting intervention, surgeons find preoperative MRI helpful in identifying unsuspected lesions.

Pelvic and hip problems

Sacroiliac (SI) joint lesion

XR

May help in investigation of seronegative arthropathy. SI joints is usually adequately demonstrated on A-P lumbar spine or pelvis.

MRI, NM, CT

MR or CTor perhaps NM when plain XRs are equivocal; earlier detection with MRI, particularly after contrast. MRI is advantageous in children and adolescents.

Hip pain: full or limited movement

XR

Symptoms often transient. Only if symptoms and signs persist or history is complex (e.g., chance of avascular necrosis) or if hip replacement might be considered.

MR

Useful to demonstrate inflammation. MR arthrography to evaluate acetabular labral tears.

Hip pain: suspected avascular necrosis

XR

Abnormal in established disease.

MR

Most sensitive in the detection of early avascular necrosis and will demonstrate extent.

Painful prosthesis

XR

To detect loosening.

NM

Normal skeletal scintigraphy excludes most late complications. Labeled white cell scintigraphy can help distinguish loosening from infection.

CT, computed tomography; DXA, dual-energy x-ray-absorptiometry; MRI, magnetic resonance imaging; NM, nuclear medicine; US, ultrasound; XR, radiography.

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