Discrepant sulfur colloid and radioparticle liver uptake in superior vena cava obstruction: case report.

The presence of collateral venous channels connecting the upper extremity veins and portal vein via the paraumbilical veins is considered the probable explanation for the observed scintigraphic hepatic "hot spot". This is seen in [99mTc]sulfur colloid liver imaging and perfusion lung imaging with 99mTc radiolabeled particles injected into an antecubital vein in the presence of superior vena caval (SVC) obstruction. The typical distribution is one of focal uptake centrally, anteriorly, and inferiorly. An unusual pattern is described in this report and mechanisms proposed for the "diffuse homogeneous" hepatic uptake also observed in a patient with SVC obstruction undergoing a perfusion lung scan.

Cerebral microvascular injury in experimental drug abuse.

An experimental drug abuse research project is reported, in which monkeys and rats were placed on various I.V. amphetamine (Desoxyn) and I.V. barbiturate (Seconal) regimes. The monkeys were studied by serial cerebral angiography. At the end of the study all animals were sacrificed for histological examination. I.V. methamphetamine produced relatively severe cerebral vascular injury and brain damage in most animals. At least part of the damage seemed to be the result of direct vascular injury, arterial and venous. The misuse of Seconal and Ritalin also appeared to be hazardous, but these studies are incomplete, and the degree of hazard has not been fully evaluated.

Computed tomography in acute posterior fossa infarcts.

Thirty-one cases of acute posterior fossa infarcts are reported. CT evidence of obliterated posterior fossa cisterns and hydrocephalus indicates a grave prognosis due to brainstem compression. Progressive obliteration of posterior fossa cisterns may be used as an indicator for surgical decompression. Patients with intact posterior fossa cisterns had good recoveries without surgical treatment. CT can be used to diagnose the very early phase of an acute posterior fossa infarct and has prognostic value in predicting the outcome.

Computed tomography of carotid-cavernous fistula.

Fourteen patients with angiographically-proven carotid-cavernous fistulas were evaluated by computed tomography (CT). Unilateral or bilateral exophthalmos was noted in 12 patients. Slight blurring of the margin of the globe was present in two, presumably due to pulsations of the globe or conjunctival edema. Superior ophthalmic veins were prominent in 12 patients and were often larger on the side of the fistula. Irregularity or absence of contrast enhancement of the superior ophthalmic vein may indicate partial or complete thrombosis. Focal bulging or diffuse distention of the cavernous sinus was noted in nine patients. Enlargement of the extraocular muscles was observed in seven with swelling of the eyelids and edema of the conjunctiva in eight patients. The pattern of venous drainage, type of fistula, and time intervals between trauma, commencement of fistula, and CT scan may affect the CT manifestations of carotid-cavernous fistulas.

The contrast-enhanced CT scan in the diagnosis of isodense subdural hematoma.

The authors review 29 cases of surgically-proven isodense subdural hematomas examined by non-contrast and contrast-enhanced computerized tomography scans. Three types of isodense collections were noted: homogeneous isodense collections, mixed-density collections, and gravitational layering within subdural collections. Contrast enhancement within the cerebral cortex, cortical vessels, and subdural membranes led to the correct diagnosis in each case. Contrast-enhanced scans are essential for the evaluation of isodense subdural hematomas.

Sarcoidosis of the parotid gland.

The clinical and radiological features of parotid-gland sarcoidosis in 22 patients are presented. This occurred in association with systemic disease as painless, diffuse and nonnodular parotid swelling. Conventional sialography usually demonstrated normal proximal ducts, a few fragile distal ducts and non-specific parenchymal nodules. Computed tomography, with or without simultaneous sialography, defined and characterised such nodules and demonstrated normal periparotid anatomy. Sialography contributes little additional information to thorough clinical examination in non-nodular or multinodular glands. However, solitary nodules appear to be better investigated by sialography, CT and CT-guided aspiration, thereby allowing diagnosis and direct medical therapy and avoiding surgery. Ultrasonography and nuclear scintigraphy were of little value in this study.

Scintigraphy in evaluation of the hypoplastic right hepatic lobe: a rare variant.

A rare variant of right hepatic lobe hypoplasia associated with high gallbladder position in the right upper abdomen is described. Pain is frequent and may be due to cholelithiasis. It is important to recognize this variant because an associated hypertrophic left hepatic lobe can clinically masquerade as an abdominal mass. Radionuclide studies and abdominal computerized tomography are useful in defining the hypertrophied left hepatic lobe and ectopic gallbladder. The duodenum and hepatic flexure are positioned high due to space left by the hypoplastic right lobe.

Computed tomography of strangulated gastric hernia complicated by perforation and pneumothorax.

A case of traumatic rupture of the diaphragm with partial gastric herniation is reported. The initial radiographic presentation was left lower lobe pneumonia. Subsequent strangulation and perforation of the stomach caused pneumothorax. Serial chest radiographs, computed tomography of the chest and abdomen with oral contrast, and a high index of suspicion were instrumental to the diagnosis. Pneumothorax, though rare, must be recognized as a morbid, obstructive phase complication of traumatic diaphragmatic hernia requiring immediate surgical intervention.

Practical CT dosimetry.

The dose from computed tomography (CT) examinations is not negligible from a radiation safety standpoint. Occasionally, one encounters a case in which an unsuspected pregnant woman undergoes a CT pelvic scan, and the radiologist is required to estimate the dose to the fetus. This article addresses practical methods of CT dosimetry with a specific discussion on fetal dose estimate. Three methods are described: (1) the use of a dose chart, (2) the pencil ionization chamber method, and (3) the thermoluminescence dosimetry (TLD) method.

Radiology of the adult sella turcica.

Radiographic changes of the sella turcica or pituitary fossa reflect multiple disease processes of intracranial, cranial and systemic origin. Their value as diagnostic aids is related to the fact that the development of the fossa depends somewhat upon that of the pituitary gland, which it partially encloses. Further, many vascular and neural structures about the base of the brain lie close to the fossa. Also, it is vulnerable to increased intracranial pressure. The ease of radiographic demonstration of the sellar components from many planes and angles allows early recognition of pathologic alterations. Radiographic anatomy, both normal and abnormal, will be discussed, as well special diagnostic procedures such as computed tomography, angiography and cerebral pneumography.

Computed tomography of the calvarium: a prospective study.

Retrospective analysis of high-resolution raw scanning data was prospectively applied in the evaluation of lesions of the scalp and the calvarium over a 12-month period. The spectrum of abnormalities identified and the impact of CT on both diagnosis and management of 25 patients are presented. Metastases and traumatic lesions were excluded. CT was useful in both diagnosis and subsequent patient management.

Computed tomography of posterior fossa trauma.

A group of 1,700 cases of head trauma were reviewed to determine the incidence of posterior fossa injuries and to assess the value of computed tomography (CT) in their diagnosis and management. In 57 cases (3.3%), the most significant and primary injuries were within the posterior fossa. These included epidural hematoma (EDH), acute and chronic subdural hematoma (SDH), and parenchymal hemorrhage and contusion of the cerebellum and brainstem. The prognosis varies with the location and severity of the injury. Brainstem injuries are associated with a high mortality rate. Computed tomography proves particularly useful in the early recognition of brainstem injury. The demonstration by CT of obliteration of the cisterns surrounding the brainstem is a reliable sign of a grave prognosis in brainstem injury. Contrast enhancement is useful in demonstrating whether the dural sinuses are displaced, thus differentiating EDH from SDH. Except in the rare case of vascular injury unassociated with EDH, CT correlated with the neurological examination is an accurate method of determining the nature, location, and extent of significant posterior fossa injury. Scans of high quality are mandatory, and frequent supplementary contrast studies are recommended.

Streaming hypointensity in hemorrhagic glioblastoma multiforme. An illustrative case.

The computed tomography, the magnetic resonance and the angiographic features of a patient with the unusual findings of multicentric intraparenchymal, subependymal and intraventricular hemorrhage in association with glioblastoma multiforme are presented. The utility of MR in demonstrating an irregular, streaming pattern of hypointensity within the lesion (and thereby suggesting an underlying neoplasm) is briefly discussed.

Computed tomography of adult colonic intussusception: clinical and experimental studies.

The CT features of a case of adult ileocolic intussusception and of experimentally induced ileocolic, cecocolic, and colocolic intussusceptions are presented. Both the clinical and experimental cases demonstrated (1) "target" masses with enveloped, eccentrically located areas of low density and (2) interspersed low- and high-density stripes within the intussusception producing a "layered" or "stratified" pattern. This layered pattern of abdominal masses may be characteristic of intussusceptions regardless of location.