Sung Tae Kim

Intraventricular meningiomas: radiological findings and clinical features in 12 patients

PURPOSEnTo characterize the computed tomography (CT) and magnetic resonance (MR) imaging findings and clinical features of intraventricular (IV) meningiomas.nnnMATERIALS AND METHODSnCT (n=8) and MR (n=12) images and medical records of 12 patients (five men and seven women; mean age, 36 years; range, 14-68 years) with pathologically proven IV meningiomas were retrospectively reviewed. Particular attention was put on the size and shape of the mass; internal architecture such as necrosis or calcification within the tumor; peritumoral edema; associated hydrocephalus and clinical features such as symptoms, treatment, and prognosis.nnnRESULTSnThere were five of benign, three of atypical, and four of malignant subtype. All lesions were located in the lateral ventricle ranging in maximum diameters from 4.0 to 7.3 cm (mean, 5.4 cm). All tumors had lobulated shape. Five (71%, 5/7) of the atypical and malignant IV meningiomas, but just two (40%, 2/5) benign IV meningiomas, had irregular lobulation. The tumors were isointense (n=7) or hypointense (n=5) to gray matter on T1-weighted images, whereas isointense (n=9) or hyperintense (n=3) on T2-weighted images. On gadolinium-enhanced T1-weighted images, homogeneous enhancement was seen in five lesions, and heterogeneous enhancement was seen in seven lesions, Most patients (n=10) had associated localized hydrocephalus due to ventricular entrapment. Intratumoral necrosis was seen in two cases (17%, 2/12), all of these were malignant subtype. In two cases of atypical and malignant subtypes, recurrences were found during the follow-up period after surgical resection.nnnCONCLUSIONnMore than half (n=7, 58%) of the IV meningiomas were of atypical (n=3) or malignant (n=4) subtype. IV meningiomas tend to have a lobulated shape, especially irregular lobulation, and intratumoral necrosis was frequently seen in the atypical or malignant subtypes.

Analysis of the layering pattern of the apparent diffusion coefficient (ADC) for differentiation of radiation necrosis from tumour progression

ObjectivesTo evaluate the added value of diffusion-weighted imaging (DWI) to perfusion-weighted imaging (PWI) for differentiating tumour progression from radiation necrosis.MethodsSixteen consecutive patients who underwent removal of a metastatic brain tumour that increased in size after stereotactic radiosurgery were retrospectively reviewed. The layering of the ADC was categorised into three patterns. ADC values were measured on each layer, and the maximum rCBV was measured. rCBV and the layering pattern of the ADC of radiation necrosis and tumour progression were compared.ResultsNine cases of radiation necrosis and seven cases of tumour progression were pathologically confirmed. Radiation necrosis (88.9xa0% vs. 14.3xa0%) showed a three-layer pattern of ADC with a middle layer of minimum ADC more frequently. If rCBV larger than 2.6 was used to differentiate radiation necrosis and tumour progression, the sensitivity was 100xa0% but specificity was 56xa0%. If the lesions with the three-layer pattern of ADC with moderately increased rCBV (2.6–4.1) were excluded from tumour progression, the sensitivity and specificity increased to 100xa0%.ConclusionsThe three-layer pattern of ADC shows high specificity in diagnosing radiation necrosis; therefore, combined analysis of the ADC pattern with rCBV may have added value in the correct differentiation of tumour progression from radiation necrosis.Key Points•MRI follow-up often reveals increasing size of enhancing lesions after stereotactic radiosurgery•Inflammation around tumour necrosis increases regional cerebral blood volume (rCBV), mimicking progression•A three-layer apparent diffusion coefficient (ADC) pattern on diffusion-weighted MRI suggests radiation necrosis.•The combined use of rCBV and DW MRI enables accurate differentiation.

Salivary duct carcinomas: clinical and CT and MR imaging features in 20 patients

IntroductionSalivary duct carcinoma (SDC) is an uncommon high grade adenocarcinoma of the salivary gland with a grave prognosis. The aim of this study was to investigate the clinical and CT and MR imaging features of SDC.MethodsWe retrospectively evaluated the clinical and CT and MR imaging findings in 20 patients (14 men and six women; mean age, 59xa0years) with histologically proved SDC. We also tried to correlate clinicoradiological tumor staging with pathologic tumor staging in 17 patients who underwent surgery.ResultsThe tumor originated in the parotid gland (nu2009=u200911; 55%), the submandibular gland (nu2009=u20097; 35%) and the buccal space along the distal Stensens duct (nu2009=u20092; 10%). Locoregional recurrence occurred in 41% and distant metastasis in 47%. Fifty-eight percent died of the disease with a mean survival period of 32xa0months after diagnosis. On CT and MR images, SDC was mostly seen as an ill-defined (85%) and infiltrative (60%) mass with frequent calcification (50%) and necrosis (80%). Although various signal intensities were seen on MR images, six of nine tumors contained the areas of marked hypointensity on T2-weighted images. Clinicoradiological tumor staging correlated well with pathologic tumor staging in 82% of the patients.ConclusionIll-defined, infiltrative mass with calcification on CT scans and the areas of marked hypointensity on T2-weighted MR images may be useful radiologic features to suggest the diagnosis of SDC. CT and MR imaging are useful for staging of SDC.

18F-FDG PET/CT findings of sinonasal inverted papilloma with or without coexistent malignancy : comparison with MR imaging findings in eight patients

IntroductionSinonasal inverted papilloma (IP) is known for high rate of associated malignancy. The purpose of this study was to identify 18F-FDG PET/CT findings of sinonasal IPs. We also tried to compare the PET/CT findings with the MR imaging findings.MethodsWe retrospectively reviewed PET/CT and MR images of eight patients with sinonasal IP with (nu2009=u20096) or without (nu2009=u20092) coexistent squamous cell carcinoma (SCC). Particular attention was paid to correlate the PET/CT findings with the MR imaging findings in terms of area distribution of standard uptake values (SUVs) and a convoluted cerebriform pattern (CCP).ResultsIn two benign IPs, the maximum SUVs measured 8.2 and 7.8, respectively (mean, 8.0). In both tumors, MR images demonstrated a diffuse CCP. In six IPs with coexistent SCC, the maximum SUVs ranged from 13.3 to 31.9 (meanu2009±u2009SD, 20.2u2009±u20096.6). In these tumors, MR images demonstrated a diffuse CCP in two, a partial CCP in three, and no CCP in one. A wide discrepancy was noted between MR imaging and PET/CT in terms of area distribution of a CCP and SUVs.ConclusionIn sinonasal lesions with MR imaging features of IP, 18F-FDG PET/CT demonstrating avid FDG uptake does not necessarily imply the presence of coexistent malignancy. In our small series, although IPs containing foci of SCC had consistently higher SUVs than IPs without SCC, the limited literature on this subject suggests that PET cannot be used reliably to make the distinction.

Signal intensity change of the labyrinth in patients with surgically confirmed or radiologically diagnosed vestibular schwannoma on isotropic 3D fluid-attenuated inversion recovery MR imaging at 3 T

ObjectiveThe purpose of this study was to evaluate the signal intensity (SI) change of the labyrinth in patients with vestibular schwannoma on isotropic 3D fluid-attenuated inversion recovery (FLAIR) imaging at 3xa0T.MethodsThirty-four patients with surgically confirmed or radiologically diagnosed vestibular schwannoma were included in this study. Retrospectively, we visually and quantitatively compared the SIs of the cochlea and vestibule on the affected side with those on the unaffected side. We also investigated whether there was correlation between the SI ratios (SIRs) of the labyrinth and the audiometric findings.ResultsOn 3D FLAIR images, the SI of the cochlea and vestibule on the affected side was significantly increased in 97% (33/34) and 91% (31/34), respectively. While the SI of the cochlea was diffusely increased, that of the vestibule was only partially increased. Quantitative study also revealed statistically significantly higher SIRs of the cochlea (0.99u2009±u20090.29) and vestibule (0.73u2009±u20090.31) on the affected side, compared with the cochlea (0.47u2009±u20090.20) and vestibule (0.19u2009±u20090.10) on the unaffected side. There was no significant correlation of the SIRs of the labyrinth with the degree of hearing loss.ConclusionIn patients with vestibular schwannoma, isotropic 3D FLAIR imaging is a useful method for the evaluation of the SI changes of the labyrinth.

Usefulness of the dynamic gadolinium-enhanced magnetic resonance imaging with simultaneous acquisition of coronal and sagittal planes for detection of pituitary microadenomas

AbstractObjectiveDoes dynamic gadolinium-enhanced imaging with simultaneous acquisition of coronal and sagittal planes improve diagnostic accuracy of pituitary microadenomas compared with coronal images alone?MethodsFifty-six patients underwent 3-T sella MRI including dynamic simultaneous acquisition of coronal and sagittal planes after gadolinium injection. According to conspicuity, lesions were divided into four scores (0, no; 1, possible; 2, probable; 3, definite delayed enhancing lesion). Additional information on supplementary sagittal images compared with coronal ones was evaluated with a 4-point score (0, no; 1, possible; 2, probable; 3, definite additional information). Accuracy of tumour detection was calculated.ResultsAverage scores for lesion detection of a combination of two planes, coronal, and sagittal images were 2.59, 2.32, and 2.18. 6/10 lesions negative on coronal images were detected on sagittal ones. Accuracy of a combination of two planes, of coronal and of sagittal images was 92.86%, 82.14% and 75%. Six patients had probable or definite additional information on supplementary sagittal images compared with coronal ones alone (10.71%).ConclusionDynamic MRI with combined coronal and sagittal planes was more accurate for detection of pituitary microadenomas than routinely used coronal images. Simultaneous dynamic enhanced acquisition can make study time fast and costs low.Key Points• We present a new dynamic MRI technique for evaluating pituitary microadenomasn • This technique provides simultaneous acquisition of contrast enhanced coronal and sagittal images.• This technique makes the diagnosis more accurate and reduces the examination time.• Such MR imaging only requires one single bolus of contrast agent.

Cervicofacial tissue infarction in patients with acute invasive fungal sinusitis: prevalence and characteristic MR imaging findings

IntroductionTissue infarction is known as one of the characteristic features of invasive fungal sinusitis (IFS). The purpose of this study was to investigate the prevalence and characteristic MR imaging findings of cervicofacial tissue infarction (CFTI) associated with acute IFS.MethodsWe retrospectively reviewed MR images in 23 patients with histologically or microbiologically proven acute IFS. CFTI was defined as an area of lack of enhancement in and around the sinonasal tract on contrast-enhanced T1-weighted images. We divided CFTI into two groups, i.e., intrasinonasal and extrasinonasal. Particular attention was paid to the location of extrasinonasal CFTI and the signal intensity of CFTI on T1- and T2-weighted images. The presence of bone destruction on CT scans was also recorded.ResultsCFTI was found in 17 (74xa0%) of 23 patients. All of these 17 patients had intrasinonasal CFTI, and 13 patients also had extrasinonasal CFTI. All 13 patients with extrasinonasal CFTI died of disease directly related to IFS. Various locations were involved in the 13 patients with extrasinonasal CFTI, including the orbit (nu2009=u20098), infratemporal fossa (nu2009=u20097), intracranial cavity (nu2009=u20093), and oral cavity and/or facial soft tissue (nu2009=u20094). Various signal intensities were noted at the area of CFTI on T1- and T2-weighted images. Bone destruction was found on CT scans in only 3 of 17 patients with CFTI.ConclusionCFTI with preservation of the bony wall of the involved sinonasal tract may be a characteristic MR imaging finding of acute IFS. The mortality is very high once the lesion extends beyond the sinonasal tract.

Spindle cell lipoma of the head and neck: CT and MR imaging findings

IntroductionSpindle cell lipoma (SCL) is an uncommon benign lipomatous tumor, most commonly occurring in the posterior neck and shoulder. The purpose of this study was to investigate the CT and MR imaging features of SCL in the head and neck.MethodsCT (nu2009=u20095) and MR (nu2009=u20093) images of seven patients (five men and two women; mean age, 54xa0years) with surgically proven SCL in the head and neck were retrospectively reviewed. The location and morphologic characteristics of SCL were documented as well.ResultsSix lesions were well-defined and located in the subcutaneous fat of the posterior neck (nu2009=u20094), anterior neck (nu2009=u20091), and buccal space (nu2009=u20091). One lesion was ill-defined and located deeply in the supraclavicular fossa, infiltrating the adjacent shoulder muscles. Intratumoral fat was identified in five lesions in various amounts. Compared with the adjacent subcutaneous fat, intratumoral fat was slightly hyperattenuated on CT scans and slightly hypointense on T1-weighted MR images. In five of six lesions in which postcontrast CT and/or MR images were obtained, significant enhancement was seen in the nonadipose component of the lesion.ConclusionVarious components of the adipose and nonadipose tissues may cause difficulty differentiating between SCL and other adipocytic tumors including liposarcoma radiologically. Although nonspecific, the radiologist should know the various imaging features of SCL, because the tumor can be cured by simple excision.

Nasal polyps with metaplastic ossification: CT and MR imaging findings

IntroductionMetaplastic ossification is a rare event in nasal polyps. The purpose of this study was to review the computed tomography (CT) and magnetic resonance (MR) imaging findings of nasal polyps with metaplastic ossification.MethodsCT (nu2009=u20095) and MR (nu2009=u20093) images of five patients (four men and one woman; mean age, 59xa0years) with surgically proven nasal polyp with metaplastic ossification were retrospectively reviewed. The location and morphologic characteristics of metaplastic ossification were documented as well.ResultsAll lesions were seen as lobulated (nu2009=u20093), ovoid (nu2009=u20091), or dumbbell-shaped (nu2009=u20091) benign-looking masses with a mean size of 3.7xa0cm (range, 2.4–6.5xa0cm), located unilaterally in the posterior nasal cavity and nasopharynx (nu2009=u20092), posterior nasoethmoidal tract (nu2009=u20092), and maxillary sinus and nasal cavity (nu2009=u20091). Compared with the brain stem, the soft tissue components of all lesions demonstrated isoattenuation on precontrast CT scans, slight hypointensity on T1-weighted MR images, and hyperintensity on T2-weighted MR images. On contrast-enhanced MR images, heterogeneous enhancement with marked peripheral enhancement was seen in two and homogeneous moderate enhancement in one. All lesions contained centrally located radiodense materials on CT scans, the shape of which was multiple clustered in three, single nodular in one, and single large lobulated in one.ConclusionAlthough rare, metaplastic ossification can occur within nasal polyps. The possibility of its diagnosis may be raised when one sees a benign-looking sinonasal mass with centrally located radiodense materials on CT scans. MR imaging may be useful when mycetoma or inverted papilloma cannot be ruled out on CT scans.

Long-term results of ethanol sclerotherapy with or without adjunctive surgery for head and neck arteriovenous malformations.

IntroductionEthanol sclerotherapy has shown favorable short-term efficacy in managing head and neck arteriovenous malformation (AVM) which is well known for high recurrence rate after treatment. The purpose of this study was to report immediate treatment results and long-term follow-up results of ethanol sclerotherapy in patients with head and neck AVMs.MethodsWe performed a retrospective review of 45 patients with head and neck AVMs treated between April 1997 and December 2013 by using ethanol sclerotherapy with or without adjunctive surgery. The degree of AVM eradication was analyzed, and complications per treatment session were recorded. Long-term treatment effectiveness was assessed with clinical and imaging follow-up.ResultsIn total, 132 sclerotherapies were performed in the 45 patients, with a total angiographic eradication rate of 17.8xa0% (nu2009=u20098). Partial resolution was achieved in 34 patients, and three patients showed no response. Mean follow-up period was 56.6xa0months (range, 13–144xa0months). The long-term recurrence rate was 11.1xa0% (5/45), and all recurrences occurred more than 3xa0years after the treatment with interval disease-controlled period. The major complication rate was 3.8xa0% (5/132), and 34 minor complications (25.8xa0%) occurred.ConclusionsEthanol sclerotherapy is effective for achieving long-term durable cure of head and neck AVMs. In patients with non-curable disease, it is also effective for symptom palliation and long-term disease control. However, given recurrence after interval disease-controlled period, long-term follow-up should be required to detect recurrence in patients with any residual lesion after treatment.