Category Archives: Principles of Assessment and Evaluation

Collateral Ligament Injuries

The collateral ligaments are best visualized by coronal MR images (Fig. 6-27). The medial collateral ligament appears as a narrow low–signal-intensity band extending from the medial epicondyle of the femur to an attachment on the anteromedial aspect of the tibia 5 to 6 cm below the joint line. It is overlaid at its tibial attachment […]

Lumbar Disc Herniation

The correlation of lumbar disc herniation with a patient’s complaints of low back pain or sciatica is not always clearly established. It has been estimated that as many as 20% of patients with radiologic findings of disc herniation are asymptomatic (67). Furthermore, when disc herniation occurs in symptomatic patients, other findings are often present that […]

Epidural Hematoma

Epidural hematoma is caused by tears of the middle meningeal artery or vein, or of a dural venous sinus. The blood accumulates in the interval between the inner table of the calvarium and the dura by gradually stripping the dura from its bony attachment. CT visualizes the epidural hematoma as a well-localized biconvex radiodense mass […]

Cruciate Ligament Injuries

The cruciate ligaments are best visualized by sagittal or oblique sagittal MR images that display the full length of the ligaments (Fig. 6-24A). On straight sagittal images, the slender nature of the anterior cruciate ligament and its oblique course cause a volume-averaging effect that averages fat signal intensity about the ligaments with the normal low […]

Cervical Spinal Stenosis and Foraminal Stenosis

Cervical spinal stenosis can be congenital or acquired. In the less common congenital stenosis, a small spinal canal is produced by short pedicles and thick laminae (62). It commonly remains asymptomatic until degenerative changes are superimposed on the congenital stenosis later in life. Acquired stenosis can be produced by a host of hyper- trophic degenerative […]

Subarachnoid and Intraventricular Hemorrhage

Subarachnoid and intraventricular hemorrhage can be spontaneous, as in the case of a bleeding aneurysm or arteriovenous malformation, or secondary to trauma. CT is the imaging modality of choice for evaluating these types of hemorrhages because it detects the hemorrhage from its onset as a hyperdensity. However, subarachnoid hemorrhage is not as radiodense as epidural […]

Cervical Disc Herniation

Disc herniation is typically preceded by degenerative changes in the mucopolysaccharides of the nucleus pulposus, which produce fibrillation of the collagen (60). This eventually causes dehydration and loss of disc volume. As a result, the nucleus pulposus no longer serves as a normal load-dispersing mechanism, and excessive stress is borne by the annulus fibrosus. This […]

Meniscal Injuries of the Knee

All parts of both menisci are well visualized by MRI. Sagittal MR images provide good views of the anterior and posterior horns and a fair view of the body of both menisci. In more central sections, both horns of the menisci appear as wedge- shaped signal voids contrasted on their superior and inferior surfaces by […]

Hemorrhagic Stroke Imaging

A stroke is considered truly hemorrhagic if blood is found within the first 24 hours after initial symptoms. When blood is noted after this time, it is usually hemorrhagic transformation of an ischemic stroke, which is due to reperfusion injury. Hypertension is the most common cause of intraparenchymal hemorrhage, which can also be caused by […]

Degenerative Disc Disease

The intervertebral disc space is a cartilaginous joint with a central nucleus pulposus surrounded by an annulus fibrosus. Degenerative change in the nucleus pulposus is termed inter-vertebral osteochondrosis (Fig. 6-49A,B). Early signs of disc disease may include loss of fluid signal within the nucleus pulposus (dehydration), which results in decreased signal within the central portion […]