Masafumi Kanoto

The efficacy of color mapped fusion images in the diagnosis and treatment of cholesteatoma using transcanal endoscopic ear surgery.

Objective To assess the efficacy of color mapped fusion images (CMFIs) in preoperatively evaluating the anatomic location of cholesteatomas and determining whether a patient is indicated for transcanal endoscopic ear surgery. Study Design Prospective case study. Setting A single university hospital. Patients Ninety-two patients scheduled for middle ear cholesteatoma surgery. Intervention Imaging analysis was first performed using echo planar diffusion-weighted imaging (EPI) for the first patient group with mixed results. Imaging analysis was then performed using 1-mm thin-slice non-EPI combined with magnetic resonance cisternography in a second group. The resulting image was then processed using color mapping to create a CMFI that enhanced cholesteatoma visualization. A second non-EPI was also performed on the third group, incorporating a T1-weighted image (T1WI) to reduce false-positives. Main Outcome Measure(s) Preoperative findings from EPI, non-EPI/CMFIs, and non-EPI/T1WI-enhanced CMFIs were compared with intraoperative findings. The positive predictive value and negative predictive value were also evaluated for each group. Results Both the positive predictive value and negative predictive value obtained from the CMFIs were high in all areas of the middle ear, and CMFI facilitated accurate detection of the anatomic location of cholesteatomas of 3 mm or larger. The incidence of false-positives was further reduced in the final 18 patients by performing T1WI to distinguish between cholesteatomas and cholesterin granulomas. Conclusion CMFI combined with T1WI is a reliable diagnostic modality for evaluating the anatomic location of cholesteatomas 3 mm or larger and determining whether transcanal endoscopic ear surgery is indicated for treatment in such cases.

Visualization of the Trochlear Nerve in the Cistern with Use of High-Resolution Turbo Spin-Echo Multisection Motion-Sensitized Driven Equilibrium

BACKGROUND AND PURPOSE: The trochlear nerve is so thin that it is rarely observed with MR imaging. Therefore, we used high-resolution MSDE to reliably visualize the cisternal segments of the trochlear nerve. MATERIALS AND METHODS: Participants were 10 healthy young adults (mean age, 24 years), and 20 trochlear nerves were examined. HR-MRC, BS-MRC, and HR-MSDE were performed. A neuroradiologist judged the visibility of the trochlear nerves as 1 of 4 grades (“Excellent,” “Good,” “Fair,” and “Not”) in each MR imaging sequence. The findings were then statistically analyzed with the χ2 test. RESULTS: Of all 20 trochlear nerves, 6 with HR-MRC, 13 with BS-MRC, and 18 with HR-MSDE were judged as “Excellent.” CSF flow-related artifacts and vessels in the cistern and cerebellar tentorium in HR-MRC tended to prevent the neuroradiologists from identifying the trochlear nerve. Vessels in the cistern and cerebellar tentorium in BS-MRC also tended to prevent the neuroradiologists from identifying the trochlear nerve. Compared with other sequences, HR-MSDE visualized the trochlear nerve more often. The χ2 test revealed statistically significant differences among the 3 MR imaging sequences (P < .01). The scan time of HR-MSDE was approximately 1.5–2.2 times longer than that of the other sequences. CONCLUSIONS: HR-MSDE is able to clearly visualize the trochlear nerve and has the same or better ability to delineate the trochlear nerve compared with other MR imaging sequences, though its long scan time does not yet yield practical use.

Radiological Image Features of the Atypical Teratoid/Rhabdoid Tumor in Adults: A Systematic Review

PurposeAtypical teratoid/rhabdoid tumor (AT/RT) occurs in children less than 3 years old, and has a very poor prognosis. AT/RT seldom occurs in adult. We have experienced four cases of AT/RT at our institute. The purpose of this study is to evaluate the radiological image findings of adult-onset AT/RT and to conduct a systematic review.MethodsImage findings of four AT/RTs in our institute were retrospectively evaluated by an experienced neuroradiologist. If the images were unavailable, image findings were evaluated from the former image interpretation report. We assembled papers of adult-onset AT/RT (n = 38) and evaluated the image findings.ResultsAT/RT occurs in a variety of sites (spinal region, pineal region, suprasellar region, jugular foramen, and so on). High density on computed tomography (CT) was seen in 10 of 11 cases; mixed intensity in T2-weighted image was seen in 13 of 18 cases; and high intensity on diffusion-weighted image (DWI) was seen in 3 of 3 cases. Contrast enhancement was observed in all cases in which images were available.ConclusionsWe have experienced four adult-onset AT/RT cases at our institute and have evaluated image findings through systematic review. The image findings of high density on CT, high intensity on DWI, with low apparent diffusion coefficient, and a heterogenous component should lead to an inclusion of AT/RT in the differential diagnosis of a tumor; these findings may be able to suggest AT/RT; however, they cannot make the diagnosis.

Delineation of malignant glioma by turbo spin echo multislice motion-sensitized driven-equilibrium (TSE-MSDE) with gadolinium-based contrast media: A case report

T1-weighted images by turbo spin echo multislice motion-sensitized driven-equilibrium with gadolinium-based contrast media clearly delineated the brainstem invasion of a malignant glioma in an 80-year-old woman compared with other magnetic resonance imaging sequences.

Brain stem and cerebellar atrophy in chronic progressive neuro-Behçet's disease

PURPOSE Chronic progressive neuro-Behçets disease (CPNBD) resembles multiple sclerosis (MS) on patient background and image findings, and therefore is difficult to diagnose. The purpose is to identify the characteristic magnetic resonance imaging (MRI) findings of CPNBD and to clarify the differences between the MRI findings of CPNBD and those of MS. MATERIALS AND METHODS The subjects consist of a CPNBD group (n=4; 1 male and 3 females; mean age, 51 y.o.), a MS group (n=19; 3 males and 16 females; mean age, 45 y.o.) and a normal control group (n=23; 10 males and 13 females; mean age, 45 y.o.). Brain stem atrophy, cerebellar atrophy, and leukoencephalopathy were retrospectively evaluated in each subjects. In middle sagittal brain MR images, the prepontine distance was measured as an indirect index of brain stem and cerebellar atrophy and the pontine and mesencephalic distance was measured as a direct index of brain stem atrophy. These indexes were statistically analyzed. RESULTS Brain stem atrophy, cerebellar atrophy, and leukoencephalopathy were seen in all CPNBD cases. Prepontine distance was significantly different between the CPNBD group and the MS group (p<0.05), and between the CPNBD group and the normal control group (p<0.001). Pontine and mesencephalic distance were significantly different between the CPNBD group and the MS group (p<0.001, p<0.01 respectively), and between the CPNBD group and the normal control group (p<0.001). CONCLUSIONS Chronic progressive neuro-Behçets disease should be considered in patients with brain stem and cerebellar atrophy in addition to leukoencephalopathy similar to that seen in multiple sclerosis.

Focal deformity of the cranial nerves observed on multislice motion-sensitized driven equilibrium (MSDE) in patients with neurovascular compression.

Objective Our purpose is to demonstrate the deformity of the cranial nerves by arterial compression using a novel technique, multislice motion-sensitized driven equilibrium (MSDE). Methods Subjects were 10 patients with neurovascular compression (5 patients with trigeminal neuralgia and 5 patients with hemifacial spasm). We observed the existence and extent of deformity of nerves by MSDE. Afterward, we compared operative findings with preoperative imaging findings and evaluated the validity of the latter. Results All compressing, blood vessels could be correctly identified through preoperative evaluation. Of all patients, 7 showed deformity of the cranial nerves, which was consistent with operative findings except in one case. In postoperative evaluation, patients’ neurological symptoms improved and the deformity disappeared. Three patients did not show deformity on preoperative MSDE images. In these patients, neural compression was also not observed during the operation. Conclusions The deformity of cranial nerves in patients with neurovascular compression was clearly shown using MSDE. Abbreviation CT - computed tomography IVH - intraventricular hemorrhage ICH - intracerebral hemorrhage DICOM - Digital Imaging and Communications in Medicine DSI - dice statistical index CLEAR-IVH - Clot Lysis Evaluating Accelerated Resolution of Intraventricular Hemorrhage Trial GT_Vol - ground truth volume Seg_Vol - segmented volume min - minimum max - maximum

MR Imaging of Uterine Epithelioid Trophoblastic Tumor: A Case Report.

Epithelioid trophoblastic tumor (ETT) is a rare gestational trophoblastic neoplasm of chorionic-type intermediate trophoblasts, and it is most frequently located in the lower uterine segment and endocervix. Due to the epithelial-growth pattern with geographic necrosis exhibited by the neoplastic cells, ETT is commonly confused, both clinically and pathologically, with squamous cell carcinoma. Although there have been no previous reports of ETT focusing on computed tomography (CT) or magnetic resonance imaging (MRI) findings, we report a case of uterine ETT with special attention to the MRI findings referring to the pathological findings and MR images of previous reports. A 42-year-old Japanese woman (gravid 1, para 1) presented with uterus enlargement during screening, and complained of recent-onset lower abdominal pain. The MRI showed a solid tumor throughout the entire myometrium of the lower uterine segment, with the hemorrhagic cystic portion extending to the posterior subserosal space. Following hysterectomy, the final pathological diagnosis was ETT. An ETT is essentially a solid tumor composed of intermediate trophoblasts that exhibit an epithelial-like growth pattern and contain geographic necrosis with calcification. In our case, MRI revealed a non-specific-intensity solid tumor in the lower uterine segment with massive necrosis and hemorrhage extending to the subserosa. While it is difficult to distinguish between ETT and uterine carcinomas, recognition of certain tumor shapes and necrosis could enable more accurate diagnosis before treatment.

Detectability and anatomical correlation of middle ear cholesteatoma using fused thin slice non-echo planar imaging diffusion-weighted image and magnetic resonance cisternography (FTS-nEPID)

Cholesteatomas show high intensity in diffusion-weighted imaging (DWI). We performed fused thin slice non-echo planar imaging (EPI) DWI and magnetic resonance cisternography (FTS-nEPID) for cholesteatoma patients to increase the detectability of FTS-nEPID for cholesteatoma. The subjects are 77 consecutive patients who underwent FTS-nEPID as a preoperative study (mean age: 53.3±21.8, 47 men and 30 women). Otorhinolaryngologists performed the operations. We anatomically classified the middle ear into four portions. A radiologist evaluated the images for cholesteatoma and assessed the anatomical invasive range in four portions using only FTS-nEPID. We classified large cholesteatomas that invaded more than three portions and small ones that invaded less than two portions based on the results obtained from surgery, and calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). For all cholesteatomas with an existing diagnosis, the sensitivity, specificity, PPV, and NPV were 71%, 70%, 94%, and 27%, respectively. In anatomical evaluation, the sensitivity, specificity, PPV, and NPV were 49%, 85%, 77%, and 64%, respectively. For large cholesteatomas with an existing diagnosis, the sensitivity was 86%. In anatomical evaluation, the sensitivity, specificity, PPV, and NPV were 51%, 57%, 88%, and 18%, respectively. For small cholesteatomas with an existing diagnosis, the sensitivity, specificity, PPV, and NPV were 59%, 78%, 92%, and 30%, respectively. In anatomical evaluation, the sensitivity, specificity, PPV, and NPV were 40%, 85%, 60%, and 71%, respectively. FTS-nEPID may be useful for diagnosing cholesteatomas. Further research is needed for anatomical evaluation because there were many false-negative results.

Inverse-direction scanning improves the image quality of whole carotid CT angiography with 64-MDCT.

PURPOSE The purpose of this prospective study was to clarify whether reducing the incidence of perivenous artifacts through craniocaudal scanning improves the quality of 64-multidetecter computed tomography (MDCT) angiography images of the whole carotid artery. METHODS Forty patients underwent MDCT angiography in the caudocranial (n=20) or craniocaudal (n=20) direction in 2007. All patients were injected with 75 ml of contrast media followed by a 35-ml saline chaser bolus at 4.0 ml/s in the right antecubital vein. Maximum intensity projection (MIP) images were scored according to image quality on a scale of 1-5. Bilateral arterial and venous attenuation was measured on 10 separated slices. We compared the mean image quality score of the two groups (i.e. those scanned caudocranially and those scanned craniocaudally). We analyzed the correlation between vascular attenuation and mean image quality. RESULTS Compared with the caudocranial group, the craniocaudal group had higher image quality scores (median, 3.70 vs. 3.40; 95% CI, 3.50-3.96 vs. 3.06-3.60; p<0.05), higher arterial attenuation (median, 550 HU vs. 489 HU; range, 270-686 vs. 302-574; p<0.05), and lower maximum venous attenuation (median, 436 vs. 1452 HU; range, 250-617 vs. 377-2044; p<0.01). Multiple regression analysis revealed that the most significant correlation factor with image quality was minimum arterial attenuation (R2=0.42, p<0.001) measured near the brachiocephalic artery. In the caudocranial group only, there was a negative correlation between right brachiocephalic venous attenuation and minimum arterial attenuation. CONCLUSIONS Compared with conventional caudocranial scanning, craniocaudal scanning improves the image quality of 64-MDCT angiography images of the whole carotid artery.

Correlation between hypoxic area in primary brain tumors and WHO grade: differentiation from malignancy using 18F-fluoromisonidazole positron emission tomography

Background 18F-fluoromisonidazole positron emission tomography (FMISO-PET) has been used for identification of hypoxic areas in tumors, and since hypoxia causes hypoxia-inducible factor-1 and enhancement of tumor growth, identifying the hypoxic area in the tumor tissue is important. Purpose To evaluate the usefulness of FMISO-PET in the grading of primary brain tumors. Material and Methods FMISO-PET was performed preoperatively on 41 consecutive patients with pathologically confirmed brain tumor. A neuroradiologist retrospectively measured both maximum standardized uptake value (SUVmax) and mean SUV (SUVmean) in the tumor and normal cerebellar parenchyma. Maximum tumor/normal control ratio (T/Nmax) and mean tumor/normal control ratio (T/Nmean) were calculated and analyzed. Results There was a positive correlation between World Health Organization (WHO) grade and both T/Nmax and T/Nmean (r = 0.731 and 0.713, respectively). When all cases were divided into benign (WHO grade II) and malignant groups (III and IV), there were significant differences between the two groups in both T/Nmax and T/Nmean (P < 0.001). If the cutoff value was defined as T/Nmax = 1.25 and T/Nmean = 1.23, T/Nmax had a sensitivity of 90.0% and a specificity of 90.9% while T/Nmean had a sensitivity of 93.3% and a specificity of 90.9% in differentiating the benign group from the malignant group. Conclusion Both T/Nmax and T/Nmean in FMISO-PET have a positive correlation with primary brain tumor grading, making FMISO-PET useful in diagnosing the malignancy of primary brain tumors.