Intravoxel Incoherent Motion MR Imaging in the Head and Neck: Correlation with Dynamic Contrast-Enhanced MR Imaging and Diffusion-Weighted Imaging

OBJECTIVE: To investigate the correlation between perfusion- and diffusion-related parameters from intravoxel incoherent motion (IVIM) and those from dynamic contrast-enhanced MR imaging (DCE-MRI) and diffusion-weighted imaging in tumors and normal muscles of the head and neck. MATERIALS AND METHODS: We retrospectively enrolled 20 consecutive patients with head and neck tumors with MR imaging performed using a 3T MR scanner. Tissue diffusivity (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) were derived from bi-exponential fitting of IVIM data obtained with 14 different b-values in three orthogonal directions. We investigated the correlation between D, f, and D* and model-free parameters from the DCE-MRI (wash-in, Tmax, Emax, initial AUC60, whole AUC) and the apparent diffusion coefficient (ADC) value in the tumor and normal masseter muscle using a whole volume-of-interest approach. Pearson's correlation test was used for statistical analysis. RESULTS: No correlation was found between f or D* and any of the parameters from the DCE-MRI in all patients or in patients with squamous cell carcinoma (p > 0.05). The ADC was significantly correlated with D values in the tumors (p 0.05, respectively). CONCLUSION: Intravoxel incoherent motion shows no significant correlation with model-free perfusion parameters derived from the DCE-MRI but is feasible for the analysis of diffusivity in both tumors and normal muscles of the head and neck.

Superior Cervical Sympathetic Ganglion: Normal Imaging Appearance on 3T-MRI

OBJECTIVE: To identify superior cervical sympathetic ganglion (SCSG) and describe their characteristic MR appearance using 3T-MRI. MATERIALS AND METHODS: In this prospective study, we recruited 53 consecutive patients without history of head and neck irradiation. Using anatomic location based on literature review, both sides of the neck were evaluated to identify SCSGs in consensus. SCSGs were divided into definite (medial to internal carotid artery [ICA] and lateral to longus capitis muscle [LCM]) and probable SCSGs based on relative location to ICA and LCM. Two readers evaluated signal characteristics including intraganglionic hypointensity of all SCSGs and relative location of probable SCSGs. Interrater and intrarater agreements were quantified using unweighted kappa. RESULTS: Ninety-one neck sites in 53 patients were evaluated after exclusion of 15 neck sites with pathology. Definite SCSGs were identified at 66 (73%) sites, and probable SCSGs were found in 25 (27%). Probable SCSGs were located anterior to LCM in 16 (18%), lateral to ICA in 6 (7%), and posterior to ICA in 3 (3%). Intraganglionic hypointensity was identified in 82 (90%) on contrast-enhanced fat-suppressed T1-weighted images. There was no statistical difference in the relative location between definite and probable SCSGs of the right and left sides with intragnalionic hypointensity on difference pulse sequences. Interrater and intrarater agreements on the location and intraganglionic hypointensity were excellent (κ-value, 0.749-1.000). CONCLUSION: 3T-MRI identified definite SCSGs at 73% of neck sites and varied location of the remaining SCSGs. Intraganglionic hypointensity was a characteristic feature of SCSGs.

Neurogenic muscle hypertrophy: a case report

Muscular hypertrophy is caused mainly due to myopathic disorder. But, it is also rarely produced by neurogenic disorder. A 74-year-old woman complained of right calf pain with hypertrophy for several years. Recent lumbar spine magnetic resonance imaging (MRI) showed central and lateral canal narrowing at the L4-L5 intervertebral space. Lower extremity MRI revealed fatty change of right medial head of the gastrocnemius and soleus, causing right calf hypertrophy. Electrodiagnostic examinations including electromyography and nerve conduction velocity testing demonstrated 5(th) lumbar and 1(st) sacral polyradiculopathy. Integrating all the results, the diagnosis was neurogenic muscle hypertrophy. Neurogenic muscle hypertrophy is very rare, but we recommend that clinicians consider this problem when a patient complains of lower limb hypertrophy and pain.

Bilateral Inferior Petrosal Sinus Sampling by Unilateral Femoral Venous Approach / 신경중재치료의학

PURPOSE: Bilateral inferior petrosal sinus sampling (IPSS) is a direct method of distinguishing between pituitary and ectopic ACTH secretion. We present unilateral femoral route technique avoiding bilateral femoral venous puncture using two 4F catheters into both sides of IPSS in these obese patients. MATERIALS AND METHODS: Unilateral femoral puncture using 9F guiding catheter allowed two 4F catheters which can be introduced in each side of inferior petrosal sinus. To reduce bleeding in the gap between 2 catheters at the diaphragm of the 9F femoral sheath, we introduced a short guidewire provided along with femoral sheath. After removing the 9F sheath after procedure, we applied manual compression as usual. We evaluated any technical difficulty and other complications including the presence of hematoma at the puncture site 1 day and 30 days later. RESULTS: Bilateral IPSS by using two 4F catheters in both inferior petrosal sinuses was possible via unilateral femoral route via 9F sheath. There was no technical difficulty introducing 4F catheters into each IPS of both sides. After removing 9F femoral sheath, there was no other complication and no hematoma at the puncture site at 1 day and 30 days later. CONCLUSION: Unilateral femoral venous approach with a 9-French sheath can be used in IPSS. This technique allowed to pass two 4F catheters for IPSS at both sides and could avoid unnecessary bilateral femoral puncture in these obese patients without any hematoma formation after the procedure.

MR Spectroscopy and Perfusion MR Imaging Findings of Intracranial Foreign Body Granuloma: a Case Report

We report a case of intracranial foreign body granuloma that showed features of a high grade tumor on magnetic resonance (MR) imaging. However, the relative cerebral blood volume was not increased in the enhancing mass on perfusion MRI and the choline/creatine ratio only slightly increased on MR spectroscopy. The results suggest that the lesion is benign in nature. Perfusion MRI and MR spectroscopy may be helpful to differentiate a foreign body granuloma from a neoplastic condition.

Percutaneous Transluminal Angioplasty for Brain Ischemia due to Takayasu's Arteritis / 신경중재치료의학

PURPOSE: To report the follow-up results of percutaneous transluminal angioplasty (PTA) of supra-aortic arteries in patients presenting with neurological manifestations caused by Takayasu's arteritis. MATERIALS AND METHODS: PTA was performed in four consecutive patients (women, age range 33-38 years) with Takayasu's arteritis (TA) with neurological manifestations (i.e., stroke, visual disturbance, and dizziness) caused by stenoocclusive lesions of supra-aortic arteries. RESULTS: PTA was attempted on 5 lesions: VA (n=3), subcalvain artery (n=1), and brachiocephalic artery (n=1). PTA was performed successfully in all patients. The neurological manifestations of the patients were improved after angioplasty. There was no immediate procedure-related complication or neurologic deficits and no restenosis on follow-up angiography in three patients. All patients were neurologically stable without occurrence of further neurological deficit during follow-up periods (9 months - 7 years). CONCLUSION: PTA of supra-aortic arteries in TA is safe and effective and provides good symptomatic relief in some patients with symptomatic multifocal stenoocclusive lesions of arch arteries.

A Case of Imploding Antrum (Silent Sinus) Syndrome after Orbital Decompression

PURPOSE: Imploding antrum (silent sinus) syndrome has clinical features of enophthalmos and hypoglobus after a downward collapse of inferior orbital wall with an ipsilateral volume decrease of maxillary sinus. We present a case of imploding antrum syndrome after an orbital decompression surgery. CASE SUMMARY: A 26-year-old female underwent inferomedial wall orbital decompression surgery through a caruncular approach to reduce exophthalmos. At 14 months after surgery, her right eye showed 2 mm of enophthalmos and orbital CT scan revealed both maxillary sinusitis. At 28 months after surgery, 3 mm of enophthalmos and hypoglobus of the right were observed, and an orbital CT scan was taken. Orbital CT scan showed a downward collapse of inferior orbital wall, a volume decrease and inward bowing of the maxillary sinus, and a maxillary opacification on the right side, which are typical findings of imploding antrum (silent sinus) syndrome. CONCLUSIONS: Imploding antrum (silent sinus) syndrome after orbital decompression surgery is a rare complication. Considering that any prolapsed orbital fat after orbital decompression surgery could result in imploding antrum syndrome with hypoventilation of a maxillary sinus, care should be taken to keep the maxillo-ethmoidal interface (bony strut) intact, which helps maintain maxillary aeration.

Comparison of Hydrogel and Silicone Hydrogel Bandage Contact Lens after LASEK

PURPOSE: To compare the effectiveness between wearing a conventional hydrogel vifilcon A bandage contact lens (BCL) and a silicone hydrogel lotrafilcon A BCL after laser-assisted subepithelial keratomileusis (LASEK). METHODS: LASEK was performed on 38 eyes of 19 patients. Each patient was fitted with a silicone hydrogel lotrafilcon A lens in one eye and a conventional hydrogel vifilcon A lens in the other eye. The patient was masked on the type of lens in each eye. General preference between the two types of lenses, subjective symptoms (pain, photophobia, tearing, dryness, and foreign body sensation; graded as 0 to 4), and the area of non-viable corneal epithelium were assessed in each eye at one and four days after surgery. RESULTS: Patients reported preferring the lotrafilcon A lens to vifilcon A at 1 (79%) and 4 (74%) days after LASEK. The mean symptom scores of tearing and foreign body sensation at 1 day after surgery (P=0.012 and P=0.034, respectively) and foreign body sensation at 4 days after surgery (P=0.027) were significantly lower in the lotrafilcon A group. The mean area of the non-viable corneal epithelium was smaller in the lotrafilcon A lens group at 1 day and 4 days after surgery, although not statistically significant. CONCLUSIONS: Patients better tolerated the silicone hydrogel lotrafilcon A BCL compared with the conventional hydrogel vifilcon A BCL. The mean symptom scores were significantly lower in the lotrafilcon A group at both 1 and 4 days after LASEK.