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Biomedical subjects

W T Djang

Publications and source records attributed to W T Djang.

At least 37 records · Page 2Linked to original sources
PubMed1987

The three lines: origin of sonographic landmarks in the fetal head.

Antenatal sonography consistently reveals three parallel echogenic lines on high-axial scans of the fetal head. Previous descriptions of fetal intracranial anatomy assumed that the inner line originates from the interhemispheric fissure and that the outer lines originate from the lateral walls of the lateral ventricles. By studying the three lines sonographically in 25 fetuses and by injecting contrast material into the deep venous system of autopsy specimens, we showed that the outer two lines do not represent the lateral walls of the lateral ventricles, but rather appear to arise from deep intracerebral veins. This finding challenges the validity of lateral ventricular hemispheric ratios in the diagnosis of early hydrocephalus, since such calculations assume that the outer lines originate from the ventricular walls rather than from veins. The results of this study reveal that the two outer lines most likely originate from deep cerebral veins, rather than from the lateral walls of the lateral ventricles.

Adult↗
PubMed1987

Radiology of acute spinal trauma.

Radiologic diagnostic modalities utilized to evaluate acute spine trauma include plain films, tomography, computerized tomography (CT), myelography and CT-myelography, and magnetic resonance imaging. The initial evaluation is aimed at delineating the nature and extent of both boney and soft tissue injuries, with particular attention directed toward differentiating intrinsic cord damage from extrinsic spinal cord or nerve root compression that may respond to surgical intervention. The selection of the optimal radiologic diagnostic algorithm requires familiarization with the techniques and limitations of each diagnostic procedure.

Algorithms↗
PubMed1986

Treatment of trilateral retinoblastoma with vincristine and cyclophosphamide.

Current therapy for patients with trilateral retinoblastoma, consisting primarily of surgical intervention and radiotherapy, has resulted in no long-term survivors. The use of adjuvant chemotherapy has not improved this outcome. After observing a tumor response to cyclophosphamide in a patient with suprasellar retinoblastoma, we treated a subsequent patient with trilateral retinoblastoma with both vincristine and cyclophosphamide. Objective tumor regression resulted. Although the tumor ultimately progressed in both patients, these findings suggest that vincristine and cyclophosphamide are active in patients with intracranial (trilateral) retinoblastoma.

Cyclophosphamide↗
PubMed1986

Craniofacial mucormycosis: assessment with CT.

Computed tomographic (CT) scans of ten patients with rhinocerebral mucormycosis were reviewed. Early paranasal sinus involvement appeared as mucosal thickening on CT scans, usually without air/fluid levels. Recognition as mucormycosis was facilitated by knowledge of the clinical setting or by identification of invasive disease. Evidence of bone destruction on CT scans was seen in only two patients, was a late finding, and usually was absent despite deep extension of disease beyond the bony confines of the paranasal sinus. Five cases had intracranial involvement, either as fungal abscess or infarction. Intracranial mucormycosis usually involved the base of the brain and cerebellum following invasion of the infratemporal fossa or orbit. Intracerebral fungal abscess appeared as low-density masses on CT scans, with variable peripheral enhancement and little surrounding vasogenic edema. Identification of a rim of spared cortex was useful in distinguishing infection from bland infarct. Serial CT scans were also useful in assessing response to hyperbaric oxygen treatment, surgery, and chemotherapy.

Adult↗
PubMed1986

Subtle cord magnetic resonance changes in cervical myelomalacia.

After spinal cord injury cystic lesions of different types are known to develop. However, in a large group of patients radiologic examinations have not revealed abnormalities in spite of neurologic deficit symptoms. Magnetic resonance imaging in 6 such patients demonstrated subtle changes in the cervical spinal cord, confirming the diagnosis of myelomalacia.

Adult↗
PubMed1984

Computed tomography of the liver: evaluating focal defects on radionuclide liver-spleen scans.

A retrospective study was undertaken to evaluate the role of computed tomography (CT) in increasing the specificity of the abnormal radiocolloid liver-spleen scan. During a 12-month period, 124 patients with focal abnormalities on hepatic scintiscans were identified out of 523 consecutive radionuclide studies. Of these 124 patients, 38 had subsequent CT examination(s) of the liver. Of this group, 11 patients with suspected metastatic disease with focal defects on hepatic scintiscans had normal hepatic CT scans and subsequent negative follow-up for hepatic disease. False-positive radionuclide scan abnormalities, related either to anatomic variation in liver configuration or adjacent extrahepatic structures influencing the radiocolloid scan, are readily recognized and explained on the basis of CT examination.

Adult↗
PubMed1983

The application of matched filtering to x-ray exposure reduction in digital subtraction angiography: clinical results.

This new digital fluorography processing method of matched filtering generates a set of images that have been acquired at continuous video-frame rates (30 per second) over the temporal extent of the bolus (10 seconds), and it combines them to produce the equivalent of a single digital subtraction angiography (DSA) image. Because of the extensive temporal averaging used, the method can provide substantial x-ray exposure reduction per run as compared with conventional techniques for an equivalent signal-to-noise ratio in the final image. The matched filtering technique was compared with conventional pulsed (one per second) DSA images of both extracranial and intracranial arteries, and the results are presented. Matched filtered images provided image quality that was equivalent to that of conventional DSA images at about one-fourth the patient exposure per run for both carotid artery and cerebral vessel studies. Despite long integration times, patient motion irretrievably corrupted image quality in only two of five carotid artery studies and in none of three intracranial studies. Compensation for patient motion is demonstrated, and additional applications and limitations of the technique are discussed.

Angiography↗
PubMed1983

Low-dose, high-frame-rate versus regular-dose, low-frame-rate digital subtraction angiography.

Using intravenous digital subtraction angiography for carotid, cerebral, and renal arteries, a comparison was made between a single pulsed image and an integrated image composed of several pulsed images. The single image was generated with a conventional detected dose per frame while the frames composing the integrated image were generated at a lower dose per frame but at a higher frame rate. Comparisons were made for an equivalent detected dose per image. For relatively stationary arteries, the integrated images were equivalent or superior to the single images. When patient motion was present, or if pulsatile vessel motion was significant, the single image was better than the integrated image. A low-dose, high-frame-rate technique has the potential for furnishing physiologic data in addition to high-quality morphologic information.

Angiography↗
PubMedDate not supplied

Digital subtraction angiography in the evaluation of neoplasms.

Intravenous and intraarterial DSA studies were performed in patients being evaluated for possible neoplastic disease. DSA studies were obtained of the head, neck, chest, abdomen and extremities to evaluate the potential use of this technique in the cancer patient's workup. The results of this study suggest that many cancer patients can have the extent of tumor involvement defined using intravenous digital subtraction angiography. However, due to the number of false negative examinations, this study should not be relied upon as the only screening procedure. The current best application of DSA appears to be its use in conjunction with intraarterial injections as a faster and more economical alternative to angiography and in following up these neoplasms with intravenous DSA after appropriate therapy to evaluate possible recurrence or metastatic spread. Hybrid subtraction techniques and/or the development of new contrast media may greatly facilitate the use of intravenous DSA in conjunction with cancer diagnosis.

Abdominal Neoplasms↗
PubMedDate not supplied

Detection of pulmonary emboli in dogs using digital subtraction angiography.

Digital subtraction angiography (DSA) was performed in six dogs to define the limits of detection of pulmonary emboli. Three angiograms were initially obtained in three normal control animals, two of which were subsequently embolized. A total of ten pulmonary angiograms were then obtained in five dogs that had experimentally produced emboli of Ivalon cubes (2, 3, and 10 mm). The intravenous angiograms were followed by selective arterial angiograms to confirm the presence and location of the emboli. The intravenous angiograms were independently reviewed by two radiologists. The criterion for detection was identification of a vessel cutoff. Perfusion defects were also seen. No intraluminal filling defects were seen. This study indicates that pulmonary emboli greater than 2 mm in diameter may be detected in dogs by DSA.

Angiography↗
PubMedDate not supplied

MR imaging of thoracic extradural arachnoid cysts.

Two extradural arachnoid cysts of the thoracic spine were studied with magnetic resonance imaging, myelography, and CT. Magnetic resonance imaging correctly characterized the extradural location of the cysts as well as the cyst contents as CSF, thus establishing the diagnosis. Magnetic resonance is helpful in the assessment of the extent of cord atrophy and myelomalacia and may be of predictive value in the postoperative prognosis.

Arachnoid↗
PubMedDate not supplied

MR imaging in patients with temporal lobe seizures: correlation of results with pathologic findings.

Thirty-nine consecutive patients with medically intractable complex partial seizures were studied with electroencephalography and MR imaging to localize an epileptogenic focus for temporal lobectomy. The patients were divided into three groups on the basis of pathologic findings after lobectomy: Group 1 comprised 13 patients with neoplasms, hamartomas, or cysts; group 2 comprised 13 patients with moderate and severe mesial temporal sclerosis (one patient was included in both groups 1 and 2); and group 3 comprised 14 patients who underwent aspiration lobectomy, which yielded limited tissue for pathologic study so no pathologic diagnosis was made. The majority of the patients in group 3 were assumed to have mesial temporal sclerosis. Abnormal MR signal in the temporal lobe on T2-weighted images was graded as minimal increase (1+), intermediate or moderate increase (2+), and very significant increase (3+). An abnormal signal was demonstrated in 26 (67%) of the 39 patients. In group 1, the tumor/cyst subgroup, an abnormal signal was seen in all 13 patients. Most had 3+ signal. There was increased signal in eight (62%) of 13 patients in group 2 and in six (43%) of 14 patients in group 3. This study suggests that MR can detect almost all tumors and a significant number of mesial temporal sclerosis lesions in individuals with complex partial seizures. On the basis of this small series, individuals who exhibit significant signal (3+) can be expected to have neoplasms, hamartomas, or cysts, and patients who exhibit minimal signal (1+) will usually have mesial temporal sclerosis.

Brain Neoplasms↗
PubMedDate not supplied

Hyperprolactinemia: an unusual manifestation of suprasellar cystic lesions.

Two patients with suprasellar cysts and hyperprolactinemia are described. These lesions were diagnosed by CT metrizamide cisternography. Suprasellar cysts are a rare cause of pathologic hyperprolactinemia, which most commonly results from pituitary adenomas. Tissue diagnosis revealed suprasellar arachnoid cysts in the first patient and Rathke's cleft cyst in the second. The differential diagnosis of suprasellar cysts is presented, and distinguishing radiographic characteristics are discussed.

Adenoma↗
PubMedDate not supplied

MR imaging of compact white matter pathways.

A prominent decreased signal intensity can be seen in many of the heavily myelinated, compact fiber pathways of the brain on T2-weighted spin-echo MR images (TR = 2500 msec, TE = 80 msec). These areas include the anterior commissure, internal capsule, optic tract and radiations, fornix, mammillothalamic tract, superior frontooccipital fasciculus, cingulum, corpus callosum, uncinate fasciculus, and superior longitudinal fasciculus. All these pathways could be identified in normal subjects 3 years old and older when 1.5-T axial and coronal images of 50 adults and 17 children were reviewed. Correlation of the in vivo and postmortem MR appearance of two human brains with Perls and Luxol fast blue stains indicates that the short T2 reflects heavy myelination and fiber density, not iron deposition. This is in contrast to the short T2 signal seen in the subcortical U fibers and deep nuclei of the brain that result from iron deposition. These pathways also differ from areas of brain iron accumulation in that (1) they may appear as areas of short T1 on partial-saturation or inversion-recovery pulse sequences and (2) they can be seen with regularity in all patients over 3 years of age. It is important to distinguish between the effect of the myelin sheath and the effect of brain iron on the T2 relaxation values seen in the normal brain since both result in shortened T2 relaxation. The importance of the role of these fiber tracts in disease processes and in modifying the spread of vasogenic edema and tumor needs further investigation.

Adolescent↗