Perfusion MR neuroimaging in patients undergoing balloon test occlusion of the internal carotid artery.

BACKGROUND AND PURPOSE: We sought to investigate whether the combination of conventional, diffusion-weighted, and perfusion-weighted MR imaging increases the diagnostic accuracy of balloon test occlusion of the internal carotid artery. We describe perfusion anomalies and patterns of enhancement seen in areas of altered brain perfusion during MR-monitored temporary balloon occlusion of the internal carotid artery. METHODS: Nine patients underwent balloon occlusion testing under standard angiographic conditions with continuous clinical and EEG monitoring. One patient who failed the test by clinical criteria underwent an external carotid to internal carotid bypass operation, followed by a repeat balloon test occlusion, thereby bringing the total number of procedures to 10. Patients were further imaged at 1.5 T with perfusion- and diffusion-weighted imaging as well as with conventional noncontrast and contrast-enhanced turbo fluid-attenuated inversion recovery (FLAIR) and T1-weighted sequences. RESULTS: Seven of 10 patients who tolerated unilateral carotid test occlusion without adverse clinical neurologic or EEG changes exhibited delayed first-pass transit of contrast material through the affected cerebral hemisphere, indicative of altered perfusion without significant concurrent cerebral blood flow or blood volume changes. Four of these patients and both symptomatic patients showed pial or subarachnoid contrast staining in areas of altered perfusion without abnormalities on diffusion-weighted images. CONCLUSION: Our findings indicate that MR perfusion-weighted imaging is safe and easily accomplished in a high-field-strength magnet and that contrast-enhanced turboFLAIR imaging may provide clinically useful MR imaging evidence of abnormal cerebral blood flow and subclinical ischemia.

Real-time, cine magnetic resonance imaging for evaluation of the pediatric airway.

BACKGROUND: Standard magnetic resonance imaging (MRI) and computed tomographic (CT) modalities are limited in their ability to image dynamic organs. New real-time, dynamic, cine magnetic resonance imaging (CMRI) techniques have the potential to image moving structures. OBJECTIVE: We therefore investigated the feasibility of using CMRI techniques to dynamically image the human airway, to assess laryngeal and tracheal patency and function. METHODS: A cohort of 10 pediatric patients, 10 adult patients, and 10 normal volunteers underwent routine static MRI, as well as CMRI using a Siemens 1.5 T Vision system (Siemens, Erlangen, Germany). Patients also underwent endoscopic evaluation. Cine axial, coronal, and sagittal sequences of the larynx and trachea were obtained during quiet respiration, as well as during a variety of provocative maneuvers. RESULTS: CMRI readily demonstrated normal vocal cord mobility and tracheal stability in normal volunteers. Abnormal vocal mobility was easily appreciated using the CMRI imaging system. Similarly, dynamic effects of tracheomalacia were clearly demonstrated using CMRI. Dynamic extrinsic tracheal compression resulting from mass lesions or anomalous vasculature was also visualized using CMRI. CONCLUSIONS: Cine MRI of the airway has the potential to provide novel data regarding laryngeal and tracheal patency and function. This evolving modality may serve as a valuable adjunct to static MR and CT imaging, as well as endoscopy, in the assessment of the airway.

A new role for magnetic resonance imaging in the diagnosis of laryngeal relapsing polychondritis.

BACKGROUND: Relapsing polychondritis involving the upper airway is a rare cause of airflow obstruction and hoarseness. The diagnosis of relapsing polychondritis depends on clinical signs, characteristic findings on cartilage biopsy, and response to treatment. Delays in diagnosis and treatment can increase the morbidity and mortality of the disease. METHODS: We present a case report of primary laryngeal relapsing polychondritis. RESULTS: Serologic testing, direct laryngoscopy, and endoscopic biopsy could not establish the diagnosis of relapsing polychondritis. Magnetic resonance imaging (MRI) examination demonstrated findings consistent with the histopathological diagnosis obtained on open biopsy. Follow-up MRI after treatment showed resolution of the initial findings. CONCLUSION: This case demonstrates the usefulness of MRI in the diagnosis and management of relapsing polychondritis involving the upper airway.

Intrathecal granuloma complicating chronic spinal infusion of morphine. Report of three cases.

Intrathecal morphine delivered by implanted pumps has been used in the treatment of pain caused by terminal cancer. Some authors supports its use in benign pain as well. The authors present three cases in which chronic infiltration of intraspinal narcotic medication was complicated by the formation of a granulomatous mass that became large enough to exert mass effect and induce neurological dysfunction.

Middle cerebral artery dissection: a clinicopathologic study.

We present a case report of a 17-year-old young man who developed fatal dissection of the middle cerebral artery after what appeared to be trivial trauma. The dissection was not evident on cerebral arteriogram but was identified at autopsy. Arterial dissection should be considered in the differential diagnosis of supraclinoid occlusion of the internal carotid artery seen by cerebral angiography.

Radiologic diagnosis and staging of head and neck squamous cell carcinoma.

The predominant extracranial head and neck cancer in adults is squamous cell carcinoma. The purpose of this article is to discuss the radiographic evaluation of these patients with computed tomography (CT) or magnetic resonance (MR) imaging prior to therapeutic intervention. Specific focus is given to the efficacy of CT and MR imaging, as an adjunct to clinical staging, for evaluation of the primary tumor, and metastatic adenopathy. MR imaging, because of its improved soft tissue contrast and multiplanar capability, is probably superior to CT for evaluation of the primary tumor in patients with squamous cell carcinoma. CT, however, remains the gold standard for identifying metastatic adenopathy and in most institutions remains the study of choice for evaluating this patient population.

Diagnostic imaging of the brain stem.

The small size of the brain stem, its location between the petrous pyramids, and the density of neuroanatomic structures in its substance make imaging of the brain stem one of the most challenging aspects of diagnostic neuroradiology. The relative value of CT, MRI, and angiography in the diagnosis of various brain stem lesions is reviewed. The contributions that can be made by more advanced diagnostic and functional imaging techniques are presented.

Pulsatile tinnitus and the vascular tympanic membrane: CT, MR, and angiographic findings.

The radiologic studies of 107 patients with pulsatile tinnitus or a vascular retrotympanic mass were retrospectively reviewed. Of the 100 patients with pulsatile tinnitus, 25 had objective tinnitus. A vascular tympanic membrane was present in 37 cases (35%). Normal vascular variants were present in 23 patients (21%). Twenty-seven patients (25%) had acquired vascular lesions. Temporal bone tumors were found in 33 patients (31%). No abnormality was identified in 21 cases (20%). To ensure optimal radiologic examination, it is imperative to know the nature of the tinnitus (objective vs subjective) and the appearance of the tympanic membrane. All patients with subjective pulsatile tinnitus or a vascular retrotympanic mass should undergo high-resolution computed tomography of the temporal bone as the initial imaging study. Angiography is recommended for patients with objective tinnitus and a normal tympanic membrane. The role of MR imaging, even with the addition of gradient-echo techniques, remains limited and secondary.

The radiologic evaluation of pulsatile tinnitus and the vascular tympanic membrane.

PT may be the only symptom signalling a need for imaging the temporal bone region. Since a wide variety of processes may be responsible for this symptom, the goal of the radiologist should be to ensure a complete, cost-effective work-up. This evaluation is best directed by the type of tinnitus, objective v subjective, and the presence or absence of a vascular retrotympanic mass. HRCT is the initial examination of choice in the majority of instances. Normal vascular variants can be confidently differentiated from paragangliomas with this study. While angiography continues to play an important role in the initial evaluation of a select group of these patients, the role of MR should be adjunctive.

Systemic absorption of gallbladder sclerosing agents in the rabbit. A preliminary study.

The absorbed levels of ethanol or tetracycline, used as gallbladder sclerosing agents, were measured in the systemic blood circulation of 16 rabbits. The maximal systemic level of ethanol was 46 mg/dl and of tetracycline was 4.6 micrograms/ml after 30 minutes of gallbladder exposure. Comparable serum levels would be considered nontoxic in humans. As a gallbladder sclerosing agent, tetracycline (50 mg/cc) was slightly more effective than 95% ethanol exposed for either 15 or 30 minutes.