chapter 4:imaging the patellofemoral joint
OTHER IMAGING TECHNIQUES
A sensitivity rate of 92% has been reported by Derks et al (56) who used ultrasound for delineation of plica synovialis. Brussaard et al (57), however, found that 22% of patellar cartilage defects were missed using ultrasound.
Intraosseous venography (58) has been reported also to be used in patients with chondromalacia and patellofemoral arthritis, demonstrating venous engorgement of the patella in both disorders.
Single photon emission computed tomographic (SPECT) bone scintigraphy has been useful in evaluating the extent of knee osteoarthritis. This technique was found by Waisbrod and Treiman (58) and Collier et al (59) to be useful for distinguishing synovitis and articular cartilage damage in the patellofemoral joint. SPECT was also useful in detecting meniscus tears, but this function has now mostly been replaced by MRl.
Minkoff and Fein (60) have pointed out that SPECT may be uniquely helpful in some difficult diagnostic problems. They describe SPECT as "a CT scan of a bone scan."
Disler et al (61) reported the use of fat‑suppressed, three‑dimensional, spoiled gradient‑recalled acquisition in the steady state in maximizing contrast between articular cartilage and fluid, fat, or muscle. This technique may be useful to enhance articular cartilage images of the patella.
Three‑dimensional reconstructions of the patellofemoral joint may provide unique insights into patellofemoral structure in certain special cases. Fractures, dysplasias, and some malalignments may be clarified using this technique (Figure 4.33).
Optical coherence tomography offers a very detailed view of articular cartilage and, while not available except in a very few major academic facilities, this offers a new and exciting way to view articular cartilage and the cellular level. Perhaps this technology will provide insight into reasons why some patients with so little actual cartilage damage have so much pain.
Inside Chapter 4: