Feng-Chi Chang

Primary Cough Headache is Associated with Posterior Fossa Crowdedness: A Morphometric MRI Study

The aetiology of primary cough headache (PCH) is obscure. The aim of this study was to investigate the magnetic resonance (MR) morphometric characteristics of the posterior cranial fossa (PCF) in patients with PCH. Eighteen consecutive patients with PCH (14M/4F, mean age 75.1 + 6.0 years) and 18 sex- and age-matched control subjects were recruited for study. Based on the midline sagittal MR images, parameters indicating posterior fossa crowdedness were measured. Compared with controls, patients with PCH had a similar size of hindbrain tissue area but a significantly smaller PCF area, resulting in a higher mean hindbrain/PCF ratio (0.78 + 0.04 vs. 0.73 + 0.06, P = 0.005). In addition, these patients also had a lower position of the cerebellar tonsillar tip, a shorter clivus length and shorter distances from the clivus to the mid-pons and from the basion to the medulla than the control group. Patients with PCH were associated with a more crowded PCF, which might be a contributing factor for the pathogenesis of this headache syndrome.

Salvage surgery for recurrent nasopharyngeal carcinoma.

Objective To evaluate the efficacy of salvage surgery in the treatment of recurrent nasopharyngeal carcinoma (NPC) at the primary site.

The current role of 1.5T non-contrast 3D time-of-flight magnetic resonance angiography to detect intracranial steno-occlusive disease

BACKGROUND/PURPOSEnThis study was performed to evaluate the role of non-contrast 3D time-of-flight (TOF) magnetic resonance angiography (MRA) to detect and quantify intracranial steno-occlusive disease.nnnMETHODSnBetween April 2004 and January 2006, 45 patients with both 1.5T TOF MRA and digital subtraction angiography (DSA) performed within a 30-day interval were included. We evaluated the following intracranial arterial segments: petrous internal carotid artery (ICA), cavernous ICA, supraclinoid ICA, M1 of middle cerebral artery, A1 of anterior cerebral artery, P1 of posterior cerebral artery, basilar artery, and distal vertebral artery. In total, 675 arterial segments were evaluated and categorized as negative, moderate-1 (3049% stenosis), moderate-2 (5069%), severe (7099% stenosis, including gap sign on MRA), and occlusion.nnnRESULTSnThe sensitivity and specificity of TOF MRA for > 29% stenosis and > 49% stenosis were 94%, 96% and 95%, 96%, respectively; while sensitivity and specificity for occlusion lesions were both 100%. However, 44 segments (37% of diseased segments) were overestimated by MRA, including 20 false-positive stenoses (which occurred in 10 [22%] patients) and 24 overestimated stenosis degree. The gap sign as severe stenosis only showed about 21% sensitivity and 41% specificity. Seven lesions were underestimated by MRA: three arterial segments were out of the field of MRA examination, and four were moderate-1stenosis on DSA.nnnCONCLUSIONnTOF MRA has high sensitivity and specificity in detecting all categories of stenosis degree and occlusion. However, it tends to overestimate lesions. Therefore, MRA can be considered as a screening study. Confirmation with other studies is recommended in doubtful cases.

Toward the Era of a One-Stop Imaging Service Using an Angiography Suite for Neurovascular Disorders

Transportation of patients requiring multiple diagnostic and imaging-guided therapeutic modalities is unavoidable in current radiological practice. This clinical scenario causes time delays and increased risk in the management of stroke and other neurovascular emergencies. Since the emergence of flat-detector technology in imaging practice in recent decades, studies have proven that flat-detector X-ray angiography in conjunction with contrast medium injection and specialized reconstruction algorithms can provide not only high-quality and high-resolution CT-like images but also functional information. This improvement in imaging technology allows quantitative assessment of intracranial hemodynamics and, subsequently in the same imaging session, provides treatment guidance for patients with neurovascular disorders by using only a flat-detector angiographic suite—a so-called one-stop quantitative imaging service (OSIS). In this paper, we review the recent developments in the field of flat-detector imaging and share our experience of applying this technology in neurovascular disorders such as acute ischemic stroke, cerebral aneurysm, and stenoocclusive carotid diseases.

Radiation acute carotid blowout syndromes of the ascending pharyngeal and internal carotid arteries in nasopharyngeal carcinoma

Acute carotid blowout syndrome (CBS) was defined as free rupture of the carotid artery associating with catastrophic hemorrhage. Most radiation acute CBSs in nasopharyngeal carcinoma (NPC) are found in petrous segment of the internal carotid artery (ICA) because of high-dose radiation in this area associated with nearby osteonecrosis. The occurrence of acute CBSs in the small branch of the external carotid artery and cervical ICA following radiotherapy in NPC patient is very rare. We present a rare case of NPC with radiation acute CBSs in the ascending pharyngeal and cervical ICA in a 3-month interval that were successfully managed by endovascular embolization.

Three-Dimensional Contrast-Enhanced Magnetic Resonance Angiography of Carotid Artery after Stenting

Purpose. This study presents 3‐dimensional, contrast‐enhanced, magnetic resonance (MR) angiographic appearances of the carotid artery after stenting. Methods. The authors reviewed contrast‐enhanced MR angiograms of 18 carotid arteries in 13 patients. These arteries were not stenotic or occluded in the stented segment, as shown on carotid angio‐grams (11 patients) or carotid Doppler images (2 patients) obtained later. Results. Five patients had 1 stent in each of their bilateral carotid arteries. One patient with 1 stent in 1 artery underwent the examination twice with different MR coils. Different artifact patterns were found in 19 carotid‐stent examinations. Type 1a involved short segments of false narrowing or false focal occlusion at both ends of the stent (n = 12); the carotid artery in the stented segment between the ends was normal. Types 2a and 2b occurred along the stented segment of the artery between the 2 ends of the stent. Type 2a was milder, with segmental faint signal intensity or luminal stenosis in the entire length of the stented segment (n = 5). Type 2b was total loss of luminal signal intensity over the whole length of the stented segment (n = 2). Last, type 1b was a band of hyperintensity at the ends of type 2a or 2b artifacts. Types 1a and 1b were due to susceptibility effect, and types 2a and 2b were from radio‐frequency shielding effect. Both of these effects were identified in MR angiogram of nitinol stents and stainless steel stents. Conclusion. Awareness of these artifacts is essential to prevent misdiagnosis.

In-room assessment of cerebral blood volume for guidance during intra-arterial thrombolytic therapy.

In acute ischemic stroke, the ability to estimate the penumbra and infarction core ratio helps to triage those who will potentially benefit from thrombolytic therapies. Flat-panel post-contrast DynaCT imaging can provide both vasculature and parenchymal blood volume within the angio room to monitor hemodynamic changes during the endovascular procedures. We report on an 80-year-old woman who suffered from an acute occlusion of the right distal cervical internal carotid artery. She was transferred to the angio room where in-room post-contrast flat-panel DynaCT imaging (syngo Neuro PBV IR) was performed to access the ischemic tissue, followed by successful mechanical thrombolytic therapy.

Transarterial Embolization of Traumatic Carotid-cavernous Fistulae by Gugliemi Detachable Coils: A Seven-year Experience

We report our experience with transarterial embolization of traumatic carotid-cavernous fistulae (TCCFs) by using Gugliemi detachable coil (GDC). From 2000 to 2007 at our institution, 11 patients with 12 TCCFs underwent transarterial GDC embolization because of failure to occlude fistulae by detachable balloon with preservation of the parent artery. The cause of the failure to occlude the fistula by detachable balloon was small fistula tract (n=9) and/or tortuous parent artery (n=3) or repeated balloon puncture by bony fragment (n=1). All TCCFs were successfully occluded by a single session transarterial GDC embolization. The average number of coils were eight (range, two-16) with an average length of 104 cm (range, 12–283 cm). No statistically significant procedure-related neurological complication or recurrent TCCF was observed in any of the patients. Transarterial GDC embolization is a useful method in the treatment of TCCFs, particularly in those TCCFs with small fistula tract or small CS.

Complications of carotid blowout syndrome in patients with head and neck cancers treated by covered stents.

The purpose of this study was to improve clinical assessment of carotid-blowout syndrome (CBS) in patients with head-and-neck cancers and with covered stents by evaluating immediate and delayed complications of reconstructive management. Eleven such patients were treated with self-expandable covered stents. We evaluated immediate and delayed complications by assessing clinical and imaging findings. Technical success and immediate hemostasis were achieved in all patients. Immediate complications were noted in four patients (36.4%), including thromboembolism in three patients and, in one patient, dissection of the carotid artery and type III endoleak by the overlapped self-expandable stent causing rebleeding. Delayed complications were noted in eight patients (72.7%), including six episodes of rebleeding in five patients, distal marginal stenosis in five patients, and delayed carotid thrombosis in three patients (one with brain abscess formation). We suggest close follow-up of the patients and aggressive re-intervention of their complications to improve outcomes.

Using Flat-Panel Perfusion Imaging to Measure Cerebral Hemodynamics: A Pilot Feasibility Study in Patients With Carotid Stenosis.

Abstract Flat-detector CT perfusion (FD-CTP) imaging has demonstrated efficacy in qualitatively accessing the penumbra in acute stroke equivalent to that of magnetic resonance perfusion (MRP). The aim of our study was to evaluate the feasibility of quantifying oligemia in the brain in patients with carotid stenosis. Ten patients with unilateral carotid stenosis of >70% were included. All MRPs and FD-CTPs were performed before stenting. Region-of-interests (ROIs) including middle cerebral artery territory at basal ganglia level on both stenotic and contralateral sides were used for quantitative analysis. Relative time to peak (rTTP) was defined as TTP of the stenotic side divided by TTP of the contralateral side, and so as relative cerebral blood volume (rCBV), relative mean transit time (rMTT), and relative cerebral blood flow (rCBF). Absolute and relative TTP, CBV, MTT, CBF between two modalities were compared. For absolute quantitative analysis, the correlation of TTP was highest (ru200a=u200a0.56), followed by CBV (ru200a=u200a0.47), MTT (ru200a=u200a0.47), and CBF (ru200a=u200a0.43); for relative quantitative analysis, rCBF was the highest (ru200a=u200a0.79), followed by rTTP (ru200a=u200a0.75) and rCBV (ru200a=u200a0.50). We confirmed that relative quantitative assessment of FD-CTP is feasible in chronic ischemic disease. Absolute quantitative measurements between MRP and FD-CTP only expressed moderate correlations. Optimization of acquisitions and algorithms is warranted to achieve better quantification.