Hao-Chun Hung

Nasal NK/T-cell Lymphoma: Computed Tomography and Magnetic Resonance Imaging Findings

Background: Primary nasal natural killer (NK)/T‐cell lymphoma is the most common cellular subtype seen in nasal lym‐phomas. It is rare in the Western population but occurs more frequently in Asia, South America, and Mexico. The purpose of this study was to describe the computed tomography (CT) and magnetic resonance (MR) imaging findings of primary nasal NK/T‐cell lymphoma. Methods: During the period between January 1990 and June 2006, the CT (n=24) and MR (n = 6) images of 24 patients with biopsy‐proved nasal NK/T‐cell lymphoma were reviewed retrospectively. Both CT and MR images were evaluated for site and extent of disease and for pattern of involvement of adjacent areas. Results: The most common symptoms at presentation were nasal obstruction, nasal discharge, and epistaxis. There was involvement of the unilateral nasal cavity in 16, bilateral nasal cavity including nasal septum in 5 and nasal choana in 3. Sites of extension outside the nasal cavity included tumor extension into paranasal sinuses (n = 15), nasopharynx (n = 5), nasal labial fold (n = 3), oropharynx (n=2), infratemporal fossa (n = 2), other subcutaneous soft tissue of the face (n = 2) and anterior cranial fossa base (n = 1). Bony destruction was demonstrated in 18 cases, involving the sinus bony wall (n = 15), nasal turbinate (n = 10), lamina papyracea (n = 6), orbital floor (n = 3), and hard palate (n = 2). Regional lymphadenopathy was also detected in 3 patients with nasal NK/T‐cell lymphoma. Conclusion: The CT and MR appearances of nasal NK/T‐cell lymphoma are nonspecific, and the diagnosis requires histologic confirmation. However, the differential diagnosis of nasal NK/T‐cell lymphoma should be included if the images present soft tissue of the nasal cavity with bony erosion or destruction; involvement of the orbital cavity, nasopharynx and infratemporal fossa; and subcutaneous or nasolabial fold soft tissue infiltration, especially in Asian populations.

Intraspinal Extradural Ganglion Cyst of the Cervical Spine

Intraspinal ganglion cyst is an uncommon lesion, which occurs most frequently in the lower lumbar region; occurrence in the cervical region is extremely rare. We report a case of ganglion cyst in the cervical region and describe its clinical pathological and radiological findings. A 59-year-old man presented with sudden lower limbs weakness and numbness below the nipple level. Magnetic resonance imaging revealed an intraspinal extradural lobulated cystic lesion at the level of C6-7 in contact with the left facet joint and posterior erosion of the spinal process at C7. The spinal cord was severely compressed by this lesion which was hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging and short T1 inversion recovery. The cyst wall was strongly enhanced after contrast injection. Intraoperatively, the mass was found to arise from the capsule of the C6-7 facet joint. The excised cyst contained jelly-like fluid. The patients neurologic symptoms had fully recovered 20 days after the operation. The histopathologic analysis was consistent with ganglion cyst. Ganglion cyst of the cervical region is extremely rare, but must be considered in the differential diagnosis of intraspinal extradural compressive syndromes.

Cerebral sinovenous thrombosis. Neuroimaging diagnosis and clinical management.

Cerebral sinovenous thrombosis (CSVT) is an uncommon disorder that affects the dural venous sinus and cerebral vein. In our study, thirty-four patients were examined. Pre and/or post contrast-enhanced CT was done in 28 patients. MRI studies were done in 24 patients. 2-D TOF MR venography (MRV) and contrast-enhanced MRV (CEMRV) were done in 19 cases. Digital subtraction angiography (DSA) was done in 18 patients. Sixteen patients received systemic intravenous heparinization, and 12 received endovascular thrombolytic treatment with urokinase combined with anticoagulant therapy. Neuroimages of CSVT can be acquired by direct visualization of the thrombus within the dural sinus or by parenchymal changes secondary to venous occlusion. As there are some pitfalls to MRI in the diagnosis of CSVT, the combination of MRI and MRV is now the gold standard in the diagnosis of CSVT. Usually, accuracy can be improved by applying 2-D TOF MRV and CE MRV. Furthermore, the source image of MRV is critical in differentiating between normal sinus variations and diseased ones. DSA is the best tool for demonstrating dynamic intracranial circulation in CSVT and mostly is used for endovascular treatment. Systemic intravenous anticoagulant therapy with heparin is accepted as a first line treatment. Except for clinical manifestations after systemic heparinization, abnormal MR findings of parenchymal change can be used to determine when to initiate thrombolytic treatment. Endovascular therapy can be finished at the ante-grade flow within the dural sinus and continuous anticoagulation is sufficient to facilitate clinical improvement. Clinical suspicion and excellent neuroimaging are crucial in making the diagnosis of CSVT. Proper management with anticoagulants and/or endovascular thrombolytic therapy is mandatory in preventing propagation of the thrombosis and improving the clinical outcome.

Neuroimaging in seizure patients associated with nonketotic hyperglycemia.

Nonketotic hyperglycemia (NKH) is a clinical syndrome consisting of hyperglycemia, hyperosmolality and intracellular dehydration but not ketoacidosis. This prospective study evaluated the clinical and magnetic resonance imaging abnormalities in six patients with NKH complicated with simple or complex partial seizures. Subcortical T2 hypointensity rather than hyperintensity together with contrast enhancement was a characteristic feature of seizures associated with NKH. Restricted diffusion on DWI and decreased NAA and/or Choline on MRS studies were also noted.

Angioplasty as the First-Line Therapeutic Option for Venous Hypertension with Outlet Obstruction of Dural Sinus

We describe a nonconventional endovascular approach to the treatment of pseudotumor cerebri with venous outlet stricture or obstruction. In three patients presenting with acute visual loss, angiograms showed sinus occlusion and stasis of contrast material, with an increased pressure gradient in the venous system. We used venous sinus angioplasty as the first therapeutic option. This treatment was effective, and symptoms and signs of all three patients subsided quickly. In our initial and limited experience, sinus balloon angioplasty appeared to be a good first-line treatment for patients with pseudotumor cerebri, sinus outlet obstruction and acute vision loss. We prefer to use sinus stent placement as a second-line option when initial attempts are unsuccessful, especially in pediatric and young-adult patients, as illustrated in our cases.

Transcutaneous puncture of the superior ophthalmic vein for embolization of dural carotid-ophthalmic fistula.

Carotid-ophthalmic fistula is a rare disease, which can be treated by transvenous endovascular embolization. Here, we report a unique case with draining vein thrombosed, making a transvenous approach impossible. An old but valuable technique, direct transcutaneous puncture of the superior ophthalmic vein, was used to save the patients right eye. The old technique, direct puncture of the superior ophthalmic vein, retains its irreplaceable usefulness in this special situation. Thus, interventional neuroradiologists should equip themselves with this essential technique.

CT and MR Angiography for Pre-Embolization Evaluation in Direct Carotid Cavernous Sinus Fistula

1283 location of the fistula shunt between the carotid artery and cavernous sinus was determined with the source images of CTA and MRA. These findings were then correlated to DSA and were used as guides to embolization. For CTA, helical CT scanners (Picker PQ 2000, PQ5000 and PQ 6000) were used. The scanning parameters were collimation 1 mm, pitch 0.5 and index 1 mm. The scan time, matrix, and FOV were 1 s/rev, 512 x 512 and 20 x 20 cm respectively.We scanned about 8 cm thickness above the C2 vertebra to cover the circle of Willis. The dynamic study was performed with one 20-gauge sheath needle inserted in the anterior cubital vein. About 95 cc contrast media was injected with flow rate of 3 cc/s by power injector. The delay time before scanning was 12 seconds to allow the contrast media to reach the intracranial arteries. 3D TOF MRA was performed at GE 1.5-T Signa MR scanner with the following parameters: 36/ minimal/1, 25 degree flip angle, 32to 40-mm slab thickness, 32 partitions, 24-cm filed of view, and 352 x 256 matrix. The actual thickness of the partitions was 1,2 mm. The cavernous sinus was located at the center of the volume slab. Introduction