An aberrant thymus is not uncommon; it is usually located in the subcutaneous tissue and attaches to deeper structures, but it rarely occurs within the dermis (dermal thymus). We report on an 8-month-old male infant with a dermal thymus. He was born with a skin tumor on the right side of the neck, located just over the sternocleidomastoid muscle. The tumor was soft, dark red, and elevated. It measured 10 by 21 mm in diameter. The surface was erosive and partially covered with crust. The infant also had a unilateral cleft lip and a deformity of the bilateral auricles. Because of recurrent episodes of infection, the tumor was resected and histologically diagnosed as a dermal thymus.

Choristoma↗

PubMedDate not supplied

Computed tomography of monkey brain tumors.

Thirty-five Japanese monkeys were inoculated intracerebrally with chick embryo fibroblasts that were producing Schmidt-Ruppin strain of Rous sarcoma virus. Tumors were induced in 54.3% (19/35). Computed tomography detected tumors in 10 symptomatic animals with an average latency of 32.6 (15-43) days. At autopsy, the brains were sectioned into 5 mm slices, coplanar to the CT image. Various CT features of high- and low-density area correlated well with the histopathological findings, such as tumor, hemorrhage, necrosis, and peritumoral edema. Contrast-enhanced CT detected 10 tumors greater than 4 mm in diameter, and there was +/- 2 mm potential error in determining tumor size. Follow-up CT revealed growth of tumors in four animals and stabilization of tumor in two animals. Large brain size, 90-110 g in adult monkeys, and availability of induced tumors offer an excellent brain tumor model for CT studies.

Animals↗

PubMedDate not supplied

Dysembryoplastic neuroepithelial tumors: MR findings.

OBJECTIVE: We report MR findings in three patients with dysembryoplastic neuroepithelial tumor (DNT), which is a recently described benign tumor in childhood or young adolescents. MATERIALS AND METHODS: The MR studies of three patients with surgically proven DNT were reviewed. All cases presented with partial complex seizures. Axial and coronal T1- and T2-weighted MR imaging of the head was performed using a 1.5 T MR unit. T1-weighted imaging after Gd-DTPA was also performed. RESULTS: The tumors were located mainly in the cortical to subcortical area with very little perifocal mass effects on MR imaging. They were essentially hypointense on T1-weighted imaging and hyperintense well-demarcated mass on T2-weighted imaging and retained a thick gyrus-like configuration within the lesions. None of them exhibited contrast enhancement after administration of Gd-DTPA. CONCLUSION: Differentiation of DNT from gangliogliomas or other low grade gliomas is possible using these MR features and is important because DNT does not recur after epilepsy surgery, therefore postoperative radiation and chemotherapy are not needed.

Adult↗

PubMedDate not supplied

Three-dimensional computed tomographic angiography of pulmonary vessels.

OBJECTIVE: To assess the image quality of multiple threshold display (MTD) as a new technique for generating three-dimensional (3D) pulmonary computed tomographic (CT) angiographic images. METHODS: We used MTD, a type of shaded surface display (SSD) offering the selection of multiple thresholds and transparencies, to reconstruct 3D-CT angiograms from enhanced helical CT data sets in 33 patients with lung disease. In MTD, eight thresholds of CT values are selected, and transparency is assigned to each. The selected voxels, ranging from -600 to 1,000 Hounsfield Units, were divided into eight classes, and transparency ranging from 0 to 100% was assigned to each. The CT scanner employed was a Toshiba Xvigor. MTD and SSD images were generated by using an Xtension with a Sun SPARC station 20, and they were compared by two radiologists. RESULTS: The image quality of MTD images was superior to that of SSD images (p < 0.01), because the MTD images demonstrated clearly both the major and small vessels. CONCLUSION: MTD is a useful technique for 3D pulmonary CT angiography.

Female↗

PubMedDate not supplied

Three-dimensional display of the bronchi using helical CT.

The purpose of this study was to evaluate the clinical usefulness of three-dimensional (3D) images of the bronchi obtained using helical CT. Thirteen patients with lung cancer, one with tracheal diverticulum, and one with bronchial amyloidosis were examined. The CT scanner employed was the Toshiba Xforce. The helical CT scan cycle consisted of 20 continuous rotations, each requiring 1.5 sec, for a total scanning time of 30 sec. Scans were obtained using a 5-mm X-ray beam width, a 5-mm/1.5 sec couchtop sliding speed, and a 2-mm reconstruction interval. 3D images were reconstructed using a CEMAX VIPstation. The optimal lower and upper threshold CT values for 3D images of the bronchi were -650 and -100 HU, respectively, and 3D images clearly depicted endobronchial lesions. Cartilage crescents were also demonstrated, but longitudinal and circular mucosal folds could not be visualized. In conclusion, 3D images of the bronchi acquired using helical CT were useful in evaluating endobronchial lesions.

Adult↗

PubMedDate not supplied

Three-dimensional display of pulmonary nodules using helical CT.

To evaluate the clinical usefulness of three-dimensional (3D) images of pulmonary nodules acquired using helical CT, 3D reconstructions were performed in 32 patients using a CEMAX VIPstation. The CT scanner employed was the Toshiba Xforce. Helical CT data were acquired using up to 20 continuous 1.5-sec rotations with an X-ray beam width of 5 mm and a couchtop movement speed of 5 mm/1.5 sec. Axial images were reconstructed at a section interval of 2 mm. The optimal lower and upper threshold CT values for 3D images were as follows: 1) solid pulmonary nodule (-700--400/-100 HU), 2) tumor invading pleura or chest wall (-700--400/-200 HU), 3) pulmonary nodule with cavity (-700--400/50 HU), 4) small pulmonary nodule (< 10 mm) (-750--650/-100 HU), and 5) arteriovenous malformation (180/500 HU). In all cases, it was possible not only to demonstrate abnormal findings three-dimensionally but also to grasp anatomical relationships among the pulmonary nodule, bronchi, vessels, and chest wall.

Adult↗

PubMedDate not supplied

MR imaging of idiopathic trigeminal neuralgia: correlation with non-surgical therapy.

Magnetic resonance (MR) findings in patients with idiopathic trigeminal neuralgia were evaluated and correlated with the effectiveness of non-surgical treatments. Thirty-four patients with idiopathic trigeminal neuralgia (ITN) were examined using T1- and T2-weighted spin-echo (SE) pulse sequence techniques to evaluate their trigeminal root-entry zones and the vessels contacted prior to non-surgical treatment (retrogasserian glycerol injection, peripheral nerve block, or only oral analgesics). Vascular contact at the proximal portion of the preganglionic segment (PGS) of the trigeminal nerve and deformity of the PGS on the affected side were observed in 97% and 47% of the patients, respectively. Non-surgical treatments were curative in 12 (67%) but failed in two (11%) of the 18 patients without deformed PGS. However, among 16 patients with deformed PGS, they were curative in only six (37.5%) and failed in four (25%). Results of this study suggest that MR imaging could be useful in the clinical assessment of trigeminal neuralgia prior to instituting non-surgical treatment.

Administration, Oral↗

PubMedDate not supplied

Plain CT findings of brain death confirmed by hollow skull sign in brain perfusion SPECT.

Computed tomographic (CT) findings of 13 patients manifesting brain death were reviewed. This diagnosis was confirmed by the so-called "hollow skull" pattern observed in brain perfusion single photon emission computed tomography (SPECT), which was performed between 4 hours before and 3 days after the CT scans, and by subsequent corporal death. The brain perfusion SPECT was performed with the intravenous administration of technetium (Tc)-99m-hexamethylpropyleneamine oxime (HMPAO) or iodine (I)-123-N-isopropyl-p-iodoamphetamine (IMP). CT scans showed diffuse cerebral edema and the loss of gray-white matter differentiation in all the cases, and transtentorial herniation in 12 patients. These CT findings were considered predictive of brain death.

Adolescent↗