Radiographic evaluation and assessment of paragangliomas.

Radiographic imaging plays an important role in the diagnosis and treatment of paragangliomas. Diagnosis and treatment should be performed as a team effort, with all the involved disciplines working together to provide the best possible individualized work-up and treatment plan for the patient.

Traumatic musculotendinous injuries of the knee: diagnosis with MR imaging.

Magnetic resonance (MR) imaging is the imaging modality of choice for evaluation of acute traumatic musculotendinous injuries of the knee. Three discrete categories of acute injuries to the musculotendinous unit can be defined: muscle contusion, myotendinous strain, and tendon avulsion. Among the quadriceps muscles, the rectus femoris is the most susceptible to injury at the myotendinous junction due to its superficial location, predominance of type II fibers, eccentric muscle action, and extension across two joints. Among the muscles of the pes anserinus, the sartorius is the most susceptible to strain injury due to its superficial location and biarticular course. The classic fusiform configuration of the semimembranosus along with a propensity for eccentric actions also make it prone to strain injury. MR imaging findings associated with rupture of the iliotibial tract include discontinuity and edema, which are best noted on coronal images. The same mechanism of injury that tears the arcuate ligament from its fibular insertion can also result in avulsion injury of the biceps femoris. The gastrocnemius muscle is prone to strain injury due to its action across two joints and its superficial location. Injuries of the muscle belly and myotendinous junction of the popliteus are far more common than tendinous injuries.

Reduction of aneurysm clip artifacts on CT angiograms: a technical note.

We describe a head tilt technique for use with CT angiography that reduces beam-hardening artifacts in patients with aneurysm clips. This simple maneuver directs the artifacts away from pertinent anatomy, thus increasing the chances for diagnostic accuracy. No significant changes in the CT angiographic protocol are required, and the maneuver can easily be combined with other artifact-minimizing strategies.

Basilar artery migraine and reversible imaging abnormalities.

We report a case of a basilar artery migraine in a 17-year-old boy with transient CT and MR abnormalities after each of two migraine episodes. A repeat MR study 6 months after the last event showed complete resolution of the lesion. Transient abnormalities on brain images similar to those shown in our case have been reported in patients with migraine and other neurologic conditions and are most likely related to cerebral vasogenic edema.

Posterior cerebral artery infarction associated with carotid dissection.

UNLABELLED: Posterior circulation stroke may rarely be associated with occlusive disease in the anterior circulation, such as in the context of a direct (fetal) origin of the posterior cerebral artery (PCA) from the internal carotid artery (ICA), or in the presence of a persistent trigeminal artery. Carotid dissection is an increasingly recognized cause of anterior circulation ischemia. It is possible that in the setting of certain cerebral hemodynamics, embolism from carotid dissection could cause PCA infarction via a patent posterior communicating artery. CASE DESCRIPTION: We report the MR and MR angiography findings of cerebral dynamics whereby a patient presents with posterior circulation symptoms from anterior circulation pathology: left ICA dissection with subsequent left PCA territory infarction. CONCLUSIONS: Cerebral hemodynamics may allow PCA infarction from carotid disease even in the absence of a fetal PCA origin. This report also broadens the spectrum of stroke associated with carotid dissection.

Cerebral venography: comparison of CT and MR projection venography.

OBJECTIVE: The purpose of the study was to show equivalence or superiority of CT venography compared with the existing test of choice--MR venography--in the evaluation of dural sinus thrombosis and in the identification of cerebral veins and dural sinuses. MATERIALS AND METHODS: Twenty-four patients underwent both CT and MR venography of the intracranial venous circulation. Seventeen patients were examined for suspected dural sinus thrombosis. Four patients underwent projection venography to assess tumor invasion of a major dural sinus. The remaining three patients were examined for cavernous sinus thrombosis, arteriovenous malformation, and an elevated jugular bulb. Without knowledge of the patients' case histories, two radiologists evaluated each CT venogram and MR venogram. The radiologists then arrived at a consensus regarding the absence or presence of dural sinus thrombosis. Later, the radiologists conducted a second interpretation with knowledge of the patients' clinical histories during which time MR and CT venograms were compared with regard to the advantages and disadvantages of each imaging technique. In addition, the venograms were assessed for the presence of 12 different venous structure. Projection venograms were displayed using a maximum-intensity-projection (MIP) algorithm, and the individual source images were also evaluated. The CT venograms were also displayed using shell-MIP and integral display algorithms. RESULTS: Using MR venography, the two radiologists diagnosed dural sinus thrombosis in eight of the 17 patients with suspected dural sinus thrombosis. In these eight patients, the diagnosis was also made with CT venography. The diagnosis was confirmed by follow-up CT in four patients and by follow-up MR imaging in two patients. The MIP algorithm did not allow direct visualization of thrombus by either the CT or the MR imaging technique; however, the CT integral display algorithm enabled direct visualization of thrombus on the three-dimensional projection venograms. The systematic comparison of imaging techniques showed that CT venography reliably reveals all cerebral veins and sinuses when they are seen with MR venography. In addition, CT venography more frequently visualizes sinuses or smaller cerebral veins with low flow as compared with MR venography. CONCLUSION: Cerebral CT venography is superior to MR venography in the identification of cerebral veins and dural sinuses and is at least equivalent in the diagnosis of dural sinus thrombosis. CT venography is a viable alternative to MR venography in the examination of patients with suspected dural sinus thrombosis.

Radiologic assessment of trauma and foreign bodies of the eye and orbit.

The detection and definition of orbital trauma is a frequent clinical problem. Therefore, the radiologic assessment is crucial. This article discusses the radiologic techniques and types of injuries that occur to the orbit.

Normal anatomy of the skull base.

CT and MR imaging increasingly are being used for the evaluation of the skull base. New innovative techniques have revolutionized radiologic understanding of normal skull base anatomy. Thus, normal anatomic relationships with radiographic correlation are vital for accurate pathologic assessment.