CT and MR Features of the Intracranial Schwannomas

PURPOSE: To evaluate CT and MR findings of the intracranial schwannomas arising from variable cranial nerves. MATERIALS AND METHODS: The authors retrospectively analyzed CT (n=21) and MR(n=15) findings of 24 cases in 23 patients(M : 7, F : 16) who had suffered from surgically-proven intracranial schwannomas over the previous fiveyears. RESULTS: Schwannomas arose from the acoustic nerve(n=18), the trigeminal nerve(n=2), the glossopha-ryngeal-vagal-accessory nerve complex (n=2), and the olfactory nerve(n=1). Intracranial schwannomas were welldefined, lobulated and inhomogeneously or homogeneously enhancing masses on CT and MR, and were located along the course of the specific cranial nerve. Acoustic schwannomas involved both the internal auditory canal(IAC) and the cerebellopontine angle(CPA) in 14 cases, the IAC in three, and the CPA in two. Two trigeminal schwannomas involved both middle and posterior cranial fossa and were in the shape of a dumbbell. One of the two schwannomas that invelved lower cranial nerve complex(9-11th) was located in the medullary cistern and jugular foramen ; the other was located in the central posterior cranial fossa. A case of olfactory schwannoma was located in the right cribriform plate. The precontrast CT scan showed low density in 13 cases(62%), isodensity in seven(33%) and highdensity in one(5%). On postcontrast CT scan, enhancement was seen in 20 cases(95%). Of the 15 cases with MR, 12had low signal intensity on T1 weighted image and 14 had high signal intensity on T2 weighted image. MR imaging after Gd-DTPA infusion showed enhancement in 14 cases. Enhancement was inhomogeneous in 14 cases on CT and in 13 on MR. Of 24 cases, intratumoral necrosis was seen in 19, ring enhancement in five and severe cystic change inone. Other findings were intratumoral calcification(21%), hemorrhage(8%), pressure bony erosion(70.8%), midline shift(58%), peritumoral edema(29%) and hydrocephalus(33%). On MR, there was in all 15 cases a peritumoral lowsignal intensity rim on T1- and T2-weighted images and on a T1 weighted image following gadolium infusion. A caseof olfactory groove schwannoma was associated with neurofibromatosis type I and a case of bilateral acoustic schwannoma with neurofibromatosis II. CONCLUSION: Schwannomas can be easily diagnosed when a well defined, lobulated and inhomogeneously enhancing mass with intratumoral necrosis, cystic change, calcification orhemorrhage is seen along the course of a cranial nerve. Peritumoral low signal intensity rim on MR may be helpful in differentiating intracranial schwannomas from other tumors.

MRI Findings of Vermian Medulloblastoma

PURPOSE: To find characteristic MRI features of vermian medulloblastoma. MATERIALS AND METHODS: MRI studiesand medical records were retrospectively reviewed for 12 patients with surgically proven midline medulloblastoma. The assessment concerned appearance of the mass in relation to surrounding structures ; MR signal intensity ; the enhancement pattern ; the mass's location and size ; presence of a cystic/necrotic area, calcification, or vascular void ; extension through the foramen Luschka ; degree of hydrocephalus ; and presence of tonsillarherniation. RESULTS: The midline medulloblastoma commonly showed roundish moon-surface appearance, especially onthe axial T2-weighted images. All tumors showed heterogeneous signal intensities mainly due to intratumoralcystic/necrotic or hemorrhagic changes. The tumors were commonly located at mid- and/or inferior vermis. Occasionally the tumors extended through the foramen Luschka, and caused obstructive hydrocephalus of moderate tosevere degree. Post-con-trast study showed heterogeneous, dense contrast enhancement in the majority of patients. CONCLUSION: The MR finding of the moon-surface appearance formed by both the mass and the intratumoralcystic/necrotic change as seen on axial T2-weighted images could be helpful in the diagnosis of vermianmedulloblastoma.

CT and MRI Findings of Malignant Meningiomas: Comparison with Benign Meningiomas

PURPOSE: The purpose is to evaluate the CT or MRI findings to help in the differentiation between benign and malignant meningiomas. MATERIAL AND METHODS: The CT and MRI findings of 8 patients with surgically proven malignant meningioma were reviewed. Four cases of 8 malignant meningiomas and 18 cases of 27 benign lesions were studied with a 1.5T or 0.5T MRI. Radiologic analysis was focused on the heterogeneity of tumor, grade of peritumoral edema, presence of cystic degeneration and calcification, tumoral enhancement pattern, dural enhancement, and tumoral border. RESULT: Histologic types of malignant meningioma were meningotheliomatous (n=4), papillary(n=1), fibroblastic(n=l), angioblastic(n=l), and sarcomatous(n=l). Tumoral Heterogeneity was seen in 8 of 8 malignant lesions(100%) and 8 of 27 benign ones(30%). (p<0.01) Marked peritumoral edema was seen in 8 of 8 malignant lesions(100%) and 2 of 27 benign ones. (7.3%)(p<0.01) Most of malignant lesions(6 of 8 cases, 75%) showed ill defined border. Calcification was not present in malignant lesions in contrast with benign ones (14 of 27 cases, 52%). (p<0.05) No statistical significance was noted in cystic degeneration, dural tail like enhancement or tumoral enhancement pattern between malignant and benign meningiomas. MRI signal intensity of malignant meningiomas was homogeneously or heterogeneously hypointense on T1WI, heterogeneously isointense or hypointense on T2WI and heterogeneous or mixed on Gd-DTPA enhancement study. CONCLUSION: The CT or MRI findings such as heterogeneity, ill defined tumoral border, marked peritumoral edema, and absence of calcification may suggest the possibility of malignancy in meningioma.

CT Findings of Spontaneous Subarachnoid Hemorrhage of Unknown Cause

PURPOSE: Spontaneous subarachnoid hemorrhage(S-SAH) is a relatively rare disease with good clinical course and prognosis. The purpose of this study is to evaluate the cisternal blood distribution on CT in patient with S-SAH. MATERIALS AND METHODS: Out of 406 patients with subarachnoid hemorrhage on brain CT scan, 11 patients confirmed to be S-SAH by angiography and clinical follow-up were examined. We analysed the CT findings of these 11 cases retrospectively. RESULTS: Five patients had only perimesencephalic distribution of hemorrhage:the prepontine, the interped- uncular, and the suprasellar cisterns were involved in 4 cases each, the basal sylvian cistern in 3 cases, and the ambient cistern in 2 cases. The quadrigeminal and a portion of the lateral sylvians were also involved in 1 case each. Six patients revealed cisternal hemorrhage extending beyond the perimesencephalic cistern into the ventricles, cortical sulci, and lateral sylvian fissure. Intraventricular hemorrhage was noted in 3 cases of these 6 patients. CONCLUSION: Our study suggests that uncomplicated clinical course and normal anglographic finding are more important than CT distribution of cisternal hemorrhage in diagnosing S-SAH.

Impact of clinical history on film interpretation

We performed a study to determine whether clinical history gives a positive or negative influence on X-ray film interpretation. One hundred and nine patient's radiograms, consisting of 55 normal and 54 abnormal cases (136 abnormalities), were interpreted twice by three pairs of residents in radiology and a pair of qualified radiologists, without clinical history first and with clinical history next. The interpreters recorded diagnosis and confidence level of normal or abnormal findings on a six-point scale. Analysis of receiver operating characteristic (ROC) curves showed that knowledge of clinical history improved diagnostic accuracy. Residents, especially beginners, should be advised to obtain clinical history whenever they read radiograms.

CT and MR findings of neuronal migration anomalies

No abstract available.

Estimation of the arterial fraction of total hepatic flow from radionuclide angiogram using 99mTc-DISIDA / 대한핵의학회잡지

No abstract available.

A case of schizencephaly with heterotopic gray matter that was only manifested a seizure attack / 신경정신의학

No abstract available.

A case of schizencephaly with heterotopic gray matter that was only manifested a seizure attack / 신경정신의학

No abstract available.

A Case of Multiple Leiomyomas of the Esophagus / 대한소화기내시경학회지

Benign tumors of the esophagus occur rarely as compared with the incidence of carcinomas. Among the benign tumors of the esophagus such as leiomyoma, lipoma, hemangioma, papilioma. polyp, cystetc. leiomyoma is the most common, although less than 10 percents of leiomyomas of the gastrointestinal tract are found in the esophagus. Most of leiomyomas of the esophagus present as solitary lesions but multiple tumors occur in about 4 percents of cases. Leiomyomas of the esophagus are diagnosed by thorough clinical evaluation, esophagogram and upper gastrofiberscopic examination but histological confirmation requires surgical or necropsy specimens. Occasionally gastrofiberscopic polypectomized specimens are used. We report one case of multiple leiomyomas of the esophagus located in between 25 cm and 40 cm distance from the incisor in a 38-year-old man who complained of vague substernal discomfort for about 10 years. Gastrofiberscopic polypectomized specimen was used for preoperative histological confirmation. The pathologic examination of the specimen showed leiomyoma of the esophagus.

A new roentgenographic method of liver size estimation on simple abdomen

It is essential to estimate the liver size in the diagnosis of liver disease. Many approaches have beenattempted in the evaluation of liver size such as measurement of length, area and volume. Among these, area andvolume measurements are accurate but complicated. So various linear measurements including Pfahler's method havebeen commonly used. But to our knowledge, there was no report about linear diameter of liver in Korean adualts. Asingeneral, larger patients are likely to have larger liver than smaller ones, it seems to be more ideal toevaluate the liver size using relative ratio rather than absolute linear diameters. The main objectives of ourinvestigation were to determine the various diameters of normal and enlarged liver and the criteria ofhepatomegaly in Korean adults using absolute and relative ments. Our cases consisted of 95 clinically normalsubjects and 51 patients suffering from liver disease and diagnosed to have hepatomegaly on abdominal palpationand simple abdomen in the Dept. of Radiology, St, Mary Hospital during the period of 6 months since Jan. 1981. Wemeasured the liver size using 3 linear diameters. And as the reference measurement, the distance from the rightmargin of the liver to the left margin of spleen was also measured. We called this “abdominal transversediameter”(ATD). The results were as follows; 1. The diameters of liver were 13.4±1.6cm, 18.4±2.4cm, 19.2±2.6cmin normal group and 18.8±3.1cm, 23.5±3.0cm, 24.2±3.2cm in hepatomegaly group using midline verticaldiameter(MIVD), maximum vertical diameter (MAVD) and diagonal diameter(DD), respectively. The difference betweentwo groups were statistically very significant in every method(p<0.01). 2. The 99% tolerance limits of liverdiameters were 13.0-13.8cm, 17.8-19.0cm, 18.5-19.9cm in normal and DD, respectively. The midpoints between theupper limit of normal group and the lower limit spectively. These points are warranted to suggest criterias ofhepatomegaly. 3. There were statistical significant difference in the ratio of each diameter to ATD between normaland hepatomegaly group (p<0.01). We called this“hepato-abdominal ratio”. The “hepato-abdominal in hepatomegalygroup using MIVD, MAVD and DD, respectively. 4. The 99% tolerance limits of “hepato-abdominal ratio” were0.43-0.45, 0.59-0.63, 0.62-0.64 in normal group and 0.60-0.62, 0.75-0.77, 0.77-0.79 in hepatomegaly group usingMAVD, MAVD and DD, respectively. The midpoints between the upper limit of normal group and the lower limit ofhepatomegaly group were 0.52, 0.69, 0.70 using MIVD, MAVD and DD, respectively. These points are alsowarranted tosuggest criterias of hepatomegaly.