Denervated muscles due to lumbar radiculopathy, peroneal axonal neuropathy and hypoglossal neuropathy were studied with magnetic resonance imaging (MRI). Denervated muscle was clearly distinguished from normal muscle by its higher intensity signal. Comparison of the resulting signal intensity of the muscle using various imaging parameters suggests an alteration in water macromolecular binding. These preliminary findings indicate that MRI may be useful in the noninvasive in vivo diagnosis and study of the effects of denervation on muscle.
Six patients receiving anticoagulant medication who had laboratory evidence of impaired hemostasis as manifested by laboratory parameters exceeding the therapeutic range developed intracranial hemorrhages. None of these patients had a history of preceding trauma. None of the 6 anticoagulated had CNS symptoms prior to initiation of anticoagulant medication. Within the intracranial hemorrhage there was a fluid-blood interface in these 6 patients; this finding was seen only in hemorrhages in anticoagulated patients. In 3 cases the fluid-blood interface changed to a homogeneous hyperdense lesion when adequate hemostasis was achieved. In one case there were multiple hemorrhages and in the other there was a solitary intracerebral hemorrhage.
A case of acute rupture of a right middle cerebral bifurcation aneurysm with extravasation of blood into a distant arachnoid cyst is reported.
CT has demonstrated its usefulness in the evaluation of the known solitary pulmonic nodule, however its application to the solitary nonpulmonic nodule has not been emphasized. Three cases illustrate the applicability of CT in localization of a nodule. The importance of obtaining bone windows in these cases is stressed. When comparison plain films and routine techniques are unsatisfactory, CT is valuable in providing a noninvasive means of diagnosis and patient reassurance.
Misinterpretation of CT scans in the skull base can result from artifacts due to abrupt density variations of anatomical structure. In this report a wide dorsum sella with low attenuation medullary cavity was initially mistaken on axial scans for an enhancing suprasellar mass. The correct diagnosis was made with follow-up scans based upon thinner cuts, slice angulation negative to the baseline, and reconstructed coronal and sagittal images,
The interesting case of the left oculomotor nerve paralysis with right hemiparesis following minor head trauma was reported in this paper. Computerized tomography showed clearly the intracranial lesions suggesting the oculomotor nerve avulsion.
Twenty-six cases of porencephalic cysts were analyzed. The cysts were multiple in 26.9% and were associated with subarachnoid cysts in 11.5%. The main presentations were seizures, cerebral palsy and mental retardation. The unifocal cysts were mainly in the frontoparietal region, suggesting a congenital aetiology. Multiple cysts were noted in the basal ganglia region. A case of multiloculated cysts, of unknown aetiology, is noted. The aetiology of multifocal porencephaly and a diagnostic method of differentiating congenital from acquired porencephaly are discussed.
A case of chordoma involving the thoracic spine (T12) is reported. The plain film findings included lytic obstruction and partial collapse of a single vertebral body. Noncontrast CT and CT following Metrizamide myelography revealed vertebral body destruction with paravertebral and intraspinal soft tissue masses. Unusual findings in the case included a photon deficient area on nuclear medicine corresponding to the lesion and normal vascularity on spinal angiography. We know of no previous report describing chordoma as a “cold” defect on bone scanning.
The use of a nasogastric tube to empty the stomach contents prevents compression of the splenic parenchyma and allows clear visualization of the anterior medial border of the spleen and perisplenic area. Unsuspected superficial lacerations or a contained hematoma by the splenic capsule may become apparent only following this procedure. A representative case is reported. Routine application of this simple procedure aids avoiding occasional pitfalls and helps in early diagnosis of splenic injury at the time of a CT study.
The CT findings in a patient with tuberous sclerosis are described with special emphasis upon the differential diagnosis. The presence of multiple bilateral subependymal nodular nonenhancing hyperdense calcified lesions is relatively characteristic of tuberous sclerosis when combined with the appropriate clinical findings. In some cases, cerebral cortical heterotopias are visualized as hypodense nonenhancing subependymal lesions. The finding of a subependymal giant cell astrocytoma is sometimes seen in patients with tuberous sclerosis, and the finding of a subependymal hyperdense enhancing lesion is consistent with this diagnosis.
Residual iophendylate in the spinal subarachnoid space may closely resemble certain spinal canal tumors on MR imaging of the spine. A knowledge of the appearance on MR imaging scans of iophendylate is essential to differentiate it from spinal tumors.
Chest radiographs and computed tomographic (CT) findings in 42 patients with pathology of the middle or posterior mediastinum, confirmed by thoracotomy, were examined retrospectively. The possibility of using contrast-enhanced CT to distinguish between cysts and solid tumors on the one hand and benign and malignant tumors on the other was assessed. All the expansions were detectable on chest radiographs. It was only by using CT, however, that the extent of the tumors could be established. Simple cysts could be identified because of their water density even without administration of contrast medium. Bronchogenic cysts simulated solid tumors but showed no contrast enhancement. Other benign tumors showed both intense homogeneous and heterogeneous contrast enhancement, as did malignant tumors. Contrast enhancement was therefore not helpful in distinguishing these benign tumors from malignant ones. Thus only infiltration to adjacent organs was found indicative of malignancy; contrast medium administration was found helpful in this respect. The use of contrast medium is thus justified in studying expansions in the middle and/or posterior mediastinum.
In the setting of a questionable pulmonary nodule demonstrated by conventional radiographs, the place of CT in the diagnostic algorithm is not well established. We reviewed our experience in 50 consecutive patients referred to CT for a “possible pulmonary nodule.” From the chest radiographs we noted nodule location, maximum dimension, presence on one or both views, and presence on a previous radiograph (> 1 year old), and nodules were categorized as “likely” or “unlikely” to be real parenchymal lesions based on radiographic appearance. Of a total of 56 questionable nodules, CT demonstrated no abnormality in 21 cases, parenchymal nodules in 16, scarring, atelectasis, or infiltrate in 11, and normal structural variants in 8. True pulmonary nodules were statistically significantly more frequently categorized as “likely” lesions than normal variants or no disease, but this was not of a magnitude to be clinically useful. Based on analysis of various radiographic features of equivocal nodules and their subsequent outcomes, we suggest a radiologic approach to the equivocal pulmonary nodule.
Difficulties in the diagnosis of cerebral thrombosis are due to the nonspecificity of symptoms and signs and the infrequent occurrence on computed tomography (CT) of direct signs of cerebral sinus thrombosis, i.e. the empty delta sign and cord sign. We present two patients, a 24/12-year-old girl with nephrotic syndrome, coma, papilledema, and hyperdensity along the sagittal sinus on CT; and a 34-year-old man with headaches, episodic visual loss, papilledema and a normal CT following posterior fossa craniotomy. On MRI, there was increased signal in sagittal and straight sinuses in the first patient, and in the lateral sinus in the second patient. The increased signal from clot, and the absence of signal from flowing blood, make MRI the procedure of choice for the initial diagnosis of cerebral sinus thrombosis.
Epidermoid and dermoid tumors are uncommon lesions and within the spinal cord are rare. Magnetic resonance imaging has proved sensitive to their detection in the intracranial cavity but the pattern of signal intensities on T1 and T2 weighted images has not been uniform. Utilizing a 0.6 T superconductive magnet an intrarnedullary cervical dermoid tumor was examined. The correlation between CT demonstrated regions of fat density and the MRI appearance of comparable regions of high intensity signal on T1 weighted images has only rarely been demonstrated in such tumors that have no histologic evidence of adipose tissue. MRI provided all of the information needed pre-operatively.
A retrospective study was done of the MRI and CT scans of 267 consecutive patients sent for an evaluation of one or more seizures. 21% (57/267) of the MRI scans were abnormal. The CT scan was normal in 28% of these MRI documented abnormal cases. In an additional 10% of these cases, MRI was more specific than CT scan. CT was more specific in cases of calcification and abscess (7%). There was one case specific than CT scan. CT was more specific in cases of calcification and abscess (7%). There was one case of undetermined pathology in which CT was abnormal despite a normal MRI. The predominant abnormalities found on MRI included tumor, infarction and vascular malformation. MRI is more sensitive than CT in noting central nervous system pathology and lesions of potential therapeutic significance in patients with seizures.
Seven cases of surgically proven intraspinal synovial cysts are reported. Computed tomographic (CT) scans demonstrated a series of low-density masses adjacent to the facet joints; in three cases, a dense rim indicated a calcified wall on the cyst; in one, the wall was partially calcified; and in three the mass appeared to be filled with gas. In all of these cases, there was severe degenerative facet disease at the same level as the synovial cyst. In six patients, the cysts were unilateral, while one was bilateral; seven cysts were located at the level of L4–L5, and one at L3-L4. We conclude from this study that the intraspinal synovial cyst can be identified reliably by the CT scan.
We discuss the clinical and CT features of certain metabolic brain disorders which cause specific CT abnormalities. These disorders may be divided into those which affect the gray matter, white matter or a combination of both gray and white matter regions. In metabolic disorders which affect the gray matter, there is ventricular enlargement with basal cistern and cortical sulcal space enlargement. In metabolic disorders which affect the white matter, there are symmetrical hypodensities seen throughout the white matter region.
The diagnosis of herniation of the left ventricle through a pericardial window was made using MRI. This is a rare type of herniation because it presented 6 years after a pericardial window was made for pericarditis. Herniation of the heart through congenital, traumatic and post surgical pericardial defects are discussed.
