Biomedical subjects
Publications and source records attributed to M Mirfakhraee.
We present an unusual radiographic manifestation of subclavian steal seen in six patients. These cases differ from the classic form of subclavian steal in that antegrade and bidirectional blood flow in the vertebral-subclavian artery system is seen, resulting in the steal phenomenon.
OBJECTIVE: To define the role of contrast-enhanced magnetic resonance imaging (MRI) as a possible adjunct to funduscopy and ultrasonography in a selected sample of non-neoplastic disorders of the chorioretina. PATIENTS AND METHODS: The study group consisted of five patients (ranging in age from 3 to 78 years) with one of the following diagnoses: ocular toxocariasis, staphyloma, glaucoma, or ocular involvement of cytomegalovirus (CMV) infection or AIDS. All of the patients underwent MRI, and the findings were correlated with those of funduscopy and ultrasonography when possible. RESULTS: There were two abnormal MRI enhancement patterns, one with and the other without major distortion of the chorioretina. Areas of abnormal enhancement correlated well with the funduscopic findings. For the patient with CMV infection and the one with AIDS, who were not examined with ultrasonography, MRI showed subtle chorioretinal abnormalities. In the other three cases, for which both ultrasonography and MRI were performed, the findings of the two methods correlated well. CONCLUSIONS: Ultrasonography remains the imaging modality of choice in the work-up of most ocular abnormalities. Ultrasonography, MRI and computed tomography are recommended when funduscopy is technically not possible. Because contrast-enhanced MRI is often performed to define the remainder of the orbit, as well as extra-orbital structures, and because of its capability to demonstrate abnormalities of the chorioretina, this modality may serve as a useful adjunct to ultrasonography. Further studies are needed to compare the efficacy of contrast-enhanced MRI and ultrasonography in the evaluation of small, nonneoplastic lesions of the chorioretina.
PURPOSE: To establish the safety, efficacy, and value of preoperative angiography in the surgical management of thoracic and lumbar spine disease, in which it is important to avoid injury to the artery of Adamkiewicz or other vessels that supply the spinal cord. METHODS: Sixty-one patients were evaluated primarily using digital subtraction angiography, low-osmolar or nonionic contrast agents, selective catheterization limited to the region of disease, and careful angiographic techniques. RESULTS: Two minor (small hematomas of the groin) and no major complications of angiography were encountered. Arterial supply to the spinal cord was identified in 22 patients. In 17 patients (77%), the arterial supply was in the region of planned surgery. In each of these patients the surgical approach was altered, either by dictating the use of a posterior surgical approach (four patients) or by altering the side of the lateral extracavitary approach (13 patients). CONCLUSION: Spinal angiography is a safe preoperative examination for thoracic and lumbar spine surgery. It is specifically useful when the lateral extracavitary surgical approach to spinal cord decompression and fusion (which predictably interrupts the terminal end-arterial blood supply to the spinal cord, if present) is planned.
We have described a patient who had lung carcinoma, syndrome of inappropriate antidiuretic hormone, and central pontine myelinolysis (CPM). Although this association is well-known, it appears to be the first report having radiographic documentation of both the intracranial and intrathoracic abnormalities. When searching for the cause of CPM, the possibility of an underlying malignancy should also be considered. This may be more common than the radiology literature would suggest.
Lymphocytic adenohypophysitis is a rare nonneoplastic cause of a pituitary mass. We report the case of an 18-year-old woman who presented with complaints of headaches and visual disturbances after an otherwise uncomplicated pregnancy and delivery. She had an elevated serum prolactin level and a pituitary mass visualized by magnetic resonance imaging (MRI). The tissue removed by transsphenoidal resection was an inflammatory mass composed of lymphocytes, plasma cells, and moderate fibrosis surrounding islands of hyperplastic lactotrophs. This is the first case of lymphocytic adenohypophysitis visualized by MRI. As in this case, lymphocytic adenohypophysitis is frequently confused with a prolactin-secreting pituitary tumor before operation and pathological examination of the tissue. The clinical characteristics and radiological features of and an approach to managing patients with lymphocytic adenohypophysitis are reviewed and discussed.
The use of intravascular catheters for diagnostic and therapeutic purposes has resulted in an increased number of foreign body embolizations. The retained foreign body is a potential source of morbidity and mortality. In this communication we describe the different techniques that are used to remove foreign bodies from various locations within the heart or vascular tree. A brief review of the literature concerning the reported complications from retained foreign bodies is made to underline the importance of early percutaneous removal of these fragments.
A modified spinal cord puncture technique that was combined with CT metrizamide syringography for the evaluation of potentially cystic spinal cord lesions has been used in 5 patients. This procedure proved to be safe and efficacious in the preoperative differentiation of cystic neoplasms from syringohydromyelia. It also aided in planning a surgical approach by revealing details of the tumor location and/or syrinx dynamics. Spinal cord puncture associated with CT metrizamide syringography has a role in the diagnosis and therapy of patients with cystic spinal cord lesions.
To establish the normal appearance of the neonatal brain, 51 neonates, 29-42 weeks postconception, underwent magnetic resonance (MR) imaging with a 0.6-T magnet in a prospective study. T1-weighted images were used to devise stages for the appearance of gray-white matter differentiation and extent of myelination. The results show that from 29 to 42 weeks postconception, changes in gray-white matter differentiation and myelination follow the stages in an orderly and predictable fashion. Changes in white matter intensity appear related to progressive decrease in brain water content. Myelination progresses cephalad from the brain stem at 29 weeks to reach the centrum semiovale by 42 weeks. Delayed myelination, defined as the absence of myelin in the corona radiata by 37 weeks, was seen in nine infants with complicated perinatal courses. Awareness of these developmental features should help to minimize misinterpretation of normal changes in the neonatal brain and lead to earlier detection of pathologic conditions, both with MR imaging and computed tomography.
Magnetic resonance (MR) imaging with a 0.6-T magnet was performed on 51 neonates, aged 29-42 weeks postconception. In 45 neonates, the ventricular/brain ratio (V/B) at the level of the frontal horns and midbody of the lateral ventricles ranged from 0.26 to 0.34. In six other infants a V/B of 0.36 or greater was associated with either cerebral atrophy or obstructive hydrocephalus. The width of the extracerebral space measured along specified points varied little in the neonatal period and ranged from 0 to 4 mm in 48 infants. Extracerebral space widths of 5-6 mm were seen in three other infants with severe asphyxia. Prominence of the subarachnoid space overlying the posterior parietal lobes is normal in neonates and should not be confused with cerebral atrophy. The authors conclude that V/B ratios of 0.26-0.34 and extracerebral space widths of 0-4 mm represent the normal range, and that neonates whose measurements exceed these values should be followed up.
A difficult and tragic case of central nervous system blastomycosis is presented as the basis for a review of the diagnostic criteria required to establish this diagnosis and to present a scheme for the diagnosis and therapy of chronic meningitis. The diagnosis in our case was complicated by preexisting inadequately treated tuberculosis; a prepontine mass; and a cervical intradural, extramedullary, circumferential mass. This exceptional case of chronic basilar meningitis with cervical myelopathy was caused by Blastomyces dermatitidis.
Three cases of documented sarcoid meningoencephalitis were reviewed. Computed tomography (CT) showed enhancing, perivascular, linear, and nodular areas along the subarachnoid space, extending deep into the white matter. In one case the perivascular granulomatous infiltration, which caused small vessel periangiitis, gave rise to a CT pattern closely resembling that of arteriovenous malformation or infarction with gyral enhancement. This infiltrative pattern might be seen in other chronic meningeal processes. The pathophysiology responsible for the unusual CT appearance and the differential diagnosis are discussed.
Nineteen patients underwent a total of 21 stump angioplasty procedures for an occluded internal carotid artery. Indications for surgery included the preparation of the donor vessel for a subsequent extracranial-intracranial bypass procedure, the occurrence of emboli to the intracranial vasculature from the external carotid artery circulation, and the association with symptomatic occlusive disease of the external carotid artery accompanying occlusion of the ipsilateral internal carotid artery. The technique utilized and the results obtained in these 19 patients are presented. In select patients, the removal of an occluded internal carotid artery stump via a stump angioplasty is beneficial in preventing the catastrophic sequela of embolic cerebrovascular disease.
The occult unilateral hydronephrotic kidney is often discovered during the genitourinary evaluation of patients sustaining blunt abdominal trauma. Few cases have been reported documenting the angiographic, computerized tomography (CT), and ultrasound appearances. Two cases are described which demonstrate that relatively minor trauma can precipitate hematuria and hypovolemic shock. Angiography demonstrated the bleeding site in both cases and was utilized in conjunction with other parameters of clinical assessment to plan initial management. CT and ultrasound proved to be useful noninvasive diagnostic parameters for baseline and follow-up studies in patients undergoing conservative management. They accurately demonstrated the degree of hydronephrosis, residual renal parenchymal, and resolving hematoma.
Thrombosis of the internal jugular vein was diagnosed by computed tomography in two cases. On contrast computed tomography, the thrombosed vein appeared as an enlarged vein containing a low density lumen surrounded by a sharply defined wall. This entity should be looked for whenever a patient is examined by computed tomography for acute cervical swelling or inflammatory ear disease.
The thin needles that are used for myelography or biopsy are easily deflected in the body. We describe a simple method used to guide the tip of these needles to the target area using needle-hub rotation. This procedure was successfully used in more than 260 direct C1-C2 punctures for cervical myelography.
Five patients with calf hematomas presented with signs and symptoms suggesting thrombophlebitis, obscuring the correct diagnosis. Venography showed no venous thrombosis; further diagnostic studies using ultrasound and/or computed tomography provided the correct diagnosis in all patients. Ultrasound showed a hypoechoic mass clearly demarcated from surrounding soft tissue, while computed tomography showed a well-defined mass whose density depended on the age of the hematoma.
Arterial bolus dynamic computed tomography (ABDCT) was performed on 52 patients presenting with intracranial and intraspinal disorders. Rapid sequential ABDCT scans were obtained during selective intraarterial injection of a small bolus of contrast material following conventional angiography. By this method, the local intravascular iodine level was maximized, allowing for improved contrast resolution of central nervous system lesions. Thirty-eight patients had a known diagnosis. In 35 of these, ABDCT was helpful in delineating tumor margins at the base of the skull and demonstrating tumor or arteriovenous malformation vascularity. In 14 patients, the diagnosis was obscure using conventional computed tomography. In eight of these, ABDCT suggested a distinction between infarct, neoplasm, and inflammatory process. In the remaining six, ABDCT was noncontributory.
The purpose of this paper is to present the computed tomography (CT) and ultrasound findings in one case of membranous obstruction of the inferior vena cava (IVC). Although the incidence of membranous obstruction of the IVC is rare in the United States, the diagnosis is essential because of the association of this lesion with portal fibrosis and hepatocellular carcinoma. Membranous obstruction of the IVC is suggested by the findings of a filling defect within the IVC at the level of either the diaphragm or right atrium. Until more specific CT and ultrasound features are described, an inferior vena cavogram will remain the definitive diagnostic procedure for membranous obstruction of the IVC.