Heung Cheol Kim

Feasibility of Intravenous Flat Panel Detector CT Angiography for Intracranial Arterial Stenosis

BACKGROUND AND PURPOSE: IV FDCT angiography is an emerging technology for the detection of intracranial vascular disease. This study was conducted to determine the feasibility of IV FDCT in estimating major atherosclerotic intracranial arterial stenosis with DSA as the reference. MATERIALS AND METHODS: DSA and IV FDCT were performed simultaneously in patients with transient ischemic attack or acute cerebral infarction. The degree and length of stenosis were measured. The stenotic vessels were categorized into 4 groups by the grade of stenosis: normal (<30%), mild (30%–49%), moderate (50%–69%), or severe (>70%). The vessels of the normal group were excluded from analysis to reduce spectrum bias. Measurement of vessels was recorded by using an electric ruler by a qualified endovascular neurosurgeon and a neuroradiologist. RESULTS: Eight hundred forty-two vessel segments in 69 patients were calculated. Mild (n = 56), moderate (n = 47) and severe stenosis (n = 46) groups were analyzed. IV FDCT had a sensitivity of 97.6%, specificity of 96.9%, and negative predictive value of 96.9% for detecting ≥50% stenosis and respective values of 91.9%, 98.2%, and 97.4% for depicting ≥70% stenosis. The difference of stenotic length between the 2 tests was not significant as an increase in the severity of stenosis (Spearman rank correlation test; r = −0.12, P = .13). CONCLUSIONS: IV FDCT can be a feasible alternative as a noninvasive method for evaluating stenosis of the major intracranial arteries.

Incidental thyroid lesions identified by ultrasound in patients with non-thyroidal head and neck cancer

Background Thyroid cancer is one of the common head and neck malignancies and may be found incidentally with other head and neck cancers. Purpose To evaluate the prevalence and risk of malignancy in incidental thyroid lesions identified by ultrasound (US) in patients with head and neck cancer. Material and Methods We retrospectively reviewed medical records of all patients with head and neck cancer other than of thyroid origin between January 2004 and December 2011. A total of 690 patients (537 men and 153 women; mean age, 58.9u2009±u200912.9 years) underwent US of the neck for the evaluation of cervical lymph node status (including thyroid gland). We evaluated the prevalence of patients with incidental thyroid lesions identified by US and the risk of malignancy in these patients. Results Of the 690 patients with head and neck cancer, 234 (33.9%) had incidental thyroid lesions on US. Based on US findings, 61 patients underwent fine-needle aspiration, with 39 eventually undergoing thyroidectomy. Among these thyroid lesions, 24 incidental thyroid lesions of 22 patients were histologically proven to be malignant (23 papillary and 1 follicular carcinomas). The risk of malignancy was 9.4% on a patient-by-patient basis. Conclusion Screening of the thyroid gland should be included in the preoperative US examination for cervical lymph node metastases in patients with non-thyroidal head and neck cancer.

Small atypical cervical nodes detected on sonography in patients with squamous cell carcinoma of the head and neck: probability of metastasis.

Objective. The purpose of this study was to assess the probability of metastasis of small atypical cervical lymph nodes detected on sonography in patients with squamous cell carcinoma (SCC) of the head and neck. Methods..We reviewed, retrospectively and blindly, sonographic findings of 148 patients (118 men and 30 women; mean age, 58.2 years) who underwent curative neck dissection. Each lymph node was classified by using a 4‐point scale: 1, definitely benign; 2, indeterminate (small [short‐axis diameter <10 mm for levels I and II and <7 mm for levels III–VI] atypical node); 3, definitely metastatic; and 4, large (>3‐cm) metastatic. Lymph nodes were considered atypical if they met at least 1 of the following criteria: a long‐ to short‐axis diameter ratio of less than 2.0, absence of a normal echogenic hilum, and heterogeneous echogenicity of the cortex. These results were verified, on a level‐by‐level basis, with histopathologic findings. Results. Small atypical nodes were found on sonography in 63 cervical levels of 48 patients, of which 18 (28.6%) were proved to have metastatic nodes. The probability of metastasis was significantly higher with than without a large (>3‐cm) ipsilateral metastatic node (0.50 versus 0.20; P = .038) and marginally higher with than without an ipsilateral metastatic node (0.41 versus 0.16; P = .061) but not significantly associated with the T stage of the primary tumor (P = .238) or the presence of an ipsilateral tumor (P = .904). Conclusions. Metastasis was encountered in about 30% of small atypical cervical nodes on sonography in patients with SCC of the head and neck. Our results indicate that small atypical nodes must be interpreted with consideration of metastatic nodes in the ipsilateral neck.

Fulminant Cerebral Infarction of Anterior and Posterior Cerebral Circulation after Ascending Type of Facial Necrotizing Fasciitis

Necrotizing fasciitis is a soft tissue infection that is characterized by extensive necrosis of the subcutaneous fat, neurovascular structures, and fascia. Cerebral infarction after facial necrotizing fasciitis has been rarely reported. A 61-year-old woman with diabetes was admitted with painful swelling of her right cheek. One day later, she was stuporous and quadriplegic. A computed tomographic scan of her face revealed right facial infection in the periorbital soft tissue, parotid, buccal muscle, and maxillary sinusitis. A computed tomographic scan of the brain revealed cerebral infarction in the right hemisphere, left frontal area, and both cerebellum. Four days later, she died from cerebral edema and septic shock. Involvement of the cerebral vasculature, such as the carotid or vertebral artery by necrotizing fasciitis, can cause cerebral infarction. Facial necrotizing fasciitis should be treated early with surgical treatment and the appropriate antibiotic therapy.

Intravenous flat-detector computed tomography angiography for high-grade carotid stenosis.

Aim The significant feature of intravenous flat-detector computed tomography (IV FDCT) angiography is its role in neurointerventional setting without patient transfer. However, few studies have addressed the accuracy of IV FDCT in estimating carotid stenosis and length. This study examined the reliability of IV FDCT in the diagnosis of high-grade carotid stenosis and stenosis length with digital subtraction angiography (DSA) as the reference. Methods Intravenous flat-detector CT and DSA were conducted simultaneously for 33 patients with 42 stenosed carotid arteries who were suspected of having symptomatic high-grade stenosis by carotid duplex ultrasound, magnetic resonance angiography, or CT angiography. The degree of stenosis and length discrepancy between 2 tests were recorded by 2 readers. Results The intraobserver and interobserver agreements were excellent for measuring high-grade carotid stenosis (&kgr; = 0.87 and 0.82). Intravenous flat-detector CT had a sensitivity of 96.3%, specificity of 93.3%, and negative predictive value of 93.3% for detecting high-grade stenosis (≥70%) compared with DSA. Bland-Altman plots demonstrated excellent correlation of the degree of stenosis IV FDCT with DSA. Length discrepancy (IV FDCT − DSA, in millimeters) did not differ significantly according to degree of stenosis (Spearman rank test; r = 0.18, P = 0.26). Conclusions Intravenous flat-detector CT can be a feasible and time-saving test for evaluating high-grade carotid stenosis and stenosis length.

Re-endovascular recanalization for acute middle cerebral artery reocclusion after surgical embolectomy

A 62-year-old woman with atrial fibrillation underwent burr hole trephination for a chronic subdural hematoma. Two days later the patient suddenly presented with motor dysphasia and slightly decreased motor power. Time of flight MR angiography revealed distal M1 occlusion without diffusion restriction. Stent-assisted mechanical thrombectomy was attempted but failed. Post-procedure MRI illustrated a small area of diffusion restriction within the peri-insular and parietal areas. Immediate surgical embolectomy was performed but reocclusion of M1 was documented in the postoperative angiography. Stent-assisted revascularization with a Solitaire stent was conducted and immediate restoration of blood flow was observed. The patients motor weakness and motor dysphasia recovered fully. Re-endovascular intervention can be beneficial in selected patients for acute middle cerebral artery reocclusion after surgical embolectomy when endovascular thrombectomy fails.