Wen-Hsien Chen

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.

Postirradiated carotid blowout syndrome in patients with nasopharyngeal carcinoma: A case–control study

Carotid blowout syndrome is one of the most devastating complications of nasopharyngeal carcinoma (NPC) therapy.

Olfactory bulb volume in Taiwanese patients with posttraumatic anosmia.

Background Olfactory bulb (OB) volume has been shown to be an indicator of olfactory function. However, few studies have been done in Asia to investigate the influence of different disorders on OB volume. Methods Data from patients with posttraumatic anosmia were collected in our department. Their olfactory thresholds were assessed by the phenyl ethyl alcohol threshold test. They were treated with a course of high-dose steroid, and followed up for at least 3 months without any olfactory improvement. Magnetic resonance imaging was subsequently used to measure patients’ OB volumes. Subjects who self-reported their olfactory function was normal were also included in the control group for comparison. Results Fifty-four patients with posttraumatic anosmia and 30 subjects who self-reported their olfactory function was normal were enrolled in this study. The mean right OB volume was 45.2 mm3, and the mean left OB volume was 46.3 mm3 in patients with posttraumatic anosmia. The mean right OB volume was 59.7 mm3, and the mean left OB volume was 66.0 mm3 in control subjects. The OB volumes were significantly lower in patients with posttraumatic anosmia. Conclusion OB volumes were significantly lower in Taiwanese patients with posttraumatic anosmia.

Assessment with magnetic resonance imaging and spectroscopy in lhermitte-duclos disease

Lhermitte-Duclos disease (LDD) is a rare benign lesion of uncertain pathogenesis characterized by distortion of the normal cerebellar laminar cytoarchitecture. We report a 22-year-old man admitted for injury sustained in a traffic accident with the incidental finding of a cerebellar mass. Magnetic resonance imaging (MRI) revealed a mass lesion within the right cerebellar hemisphere. The final diagnosis of LDD was made by obtaining a surgical specimen and identifying the characteristic appearance of the lesion by MRI study. The images showed the typical striated pattern of hyperintensity on T2-weighted images and corresponding hypointensity on T1-weighted images, as well as the typical absence of enhancement following gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) administration. In addition, no disturbance of water diffusion on diffusion-weighted MRI, and associations of decreases in the N-acetylaspartate/creatine (NAA/Cr) and NAA/Choline (Cho) ratios with near normal values of Cho/Cr, as well as an obvious lactate peak gave supplemental information for diagnosis.

Magnetic Resonance Angiography in the Diagnosis of Cerebral Arteriovenous Malformation and Dural Arteriovenous Fistulas: Comparison of Time-Resolved Magnetic Resonance Angiography and Three Dimensional Time-of-Flight Magnetic Resonance Angiography

Background Traditional digital subtraction angiography (DSA) is currently the gold standard diagnostic method for the diagnosis and evaluation of cerebral arteriovenous malformation (AVM) and dural arteriovenous fistulas (dAVF). Objectives The aim of this study was to analyze different less invasive magnetic resonance angiography (MRA) images, time-resolved MRA (TR-MRA) and three-dimensional time-of-flight MRA (3D TOF MRA) to identify their diagnostic accuracy and to determine which approach is most similar to DSA. Patients and Methods A total of 41 patients with AVM and dAVF at their initial evaluation or follow-up after treatment were recruited in this study. We applied time-resolved angiography using keyhole (4D-TRAK) MRA to perform TR-MRA and 3D TOF MRA examinations simultaneously followed by DSA, which was considered as a standard reference. Two experienced neuroradiologists reviewed the images to compare the diagnostic accuracy, arterial feeder and venous drainage between these two MRA images. Inter-observer agreement for different MRA images was assessed by Kappa coefficient and the differences of diagnostic accuracy between MRA images were evaluated by the Wilcoxon rank sum test. Results Almost all vascular lesions (92.68%) were correctly diagnosed using 4D-TRAK MRA. However, 3D TOF MRA only diagnosed 26 patients (63.41%) accurately. There were statistically significant differences regarding lesion diagnostic accuracy (P = 0.008) and venous drainage identification (P < 0.0001) between 4D-TRAK MRA and 3D TOF MRA. The results indicate that 4D-TRAK MRA is superior to 3D TOF MRA in the assessment of lesions. Conclusion Compared with 3D TOF MRA, 4D-TRAK MRA proved to be a more reliable screening modality and follow-up method for the diagnosis of cerebral AVM and dAVF.

Time-Resolved Magnetic Resonance Angiography in the Evaluation of Intracranial Vascular Lesions and Tumors: A Pictorial Essay of Our Experience

Time-resolved magnetic resonance angiography (TR MRA) is a promising less invasive technique for the diagnosis of intracranial vascular lesions and hypervascular tumors. Similar to 4-dimensional computed tomographic angiography obtaining high frame rate images, TR MRA utilizes acceleration techniques to acquire sequential arterial and venous phase images for identifying, localizing, and classifying vascular lesions. Because of the good agreement with digital subtraction angiography for grading brain arteriovenous malformations with the Spetzler–Martin classification and the good sensitivity for visualizing arteriovenous fistulas, studies have suggested that TR MRA could serve as a screening or routine follow-up tool for diagnosing intracranial vascular disorders. In this pictorial essay, we report on the use of TR MRA at 3.0 T to diagnose intracranial vascular lesions and hypervascular tumors, employing DSA as the reference technique.

Usefulness of Multidetector Row CT for Comprehensive Preoperative Evaluation of Neck Arteriovenous Malformation: Insight From a Patient With Angiography and Surgery Comparison

Abstract Neck arteriovenous malformation (AVM) is an uncommon high flow vascular lesion. In the past, because of limitations in magnetic resonance imaging and sonography, invasive angiography was usually necessary for diagnosis and surgical planning. Here, we present a 33-year-old woman with neck AVM. Multidetector row computed tomography (MDCT) provided comprehensive preoperative information, including the anatomic location, feeding artery and draining veins of the lesion. This report demonstrates that MDCT has evolved into a mature technology that can be an alternative tool and probably a new paradigm in the diagnosis of and surgical planning for AVMs.

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.