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Biomedical subjects

M D Dake

Publications and source records attributed to M D Dake.

At least 91 records · Page 5Linked to original sources
PubMed1993

Three-dimensional spiral computed tomographic angiography: an alternative imaging modality for the abdominal aorta and its branches.

PURPOSE: We sought to apply a new technique of computed tomographic angiography (CTA) to the preoperative and postoperative assessment of the abdominal aorta and its branches. METHODS: After a peripheral intravenous contrast injection, the patient is continuously advanced through a spiral CT scanner, while maintaining a 30-second breath-hold. Thirty-five patients with abdominal aortic, renal, and visceral arterial disease have undergone CTA. RESULTS: Diagnostic three-dimensional images were obtained in patients with aortic aneurysms (n = 9), aortic dissections (n = 4), and mesenteric artery stenoses (n = 4). The technique has also been used to assess vessels after operative reconstruction or endovascular intervention in 18 patients. These preliminary studies have correlated well with conventional arteriographic findings. In aneurysmal disease both the lumen and mural thrombus and associated renal artery stenoses are visualized. The true and false channels of aortic dissections and the perfusion source of the visceral vessels are clearly shown; patency of visceral and renal reconstruction or stent placement are confirmed. CTA is relatively noninvasive and can be completed in less time than conventional angiography with less radiation exposure. CONCLUSIONS: This initial experience suggests that CTA may be a valuable alternative to conventional arteriography in the evaluation of the aorta and its branches.

Adult↗
PubMed1992

Coaxial transthoracic fine-needle biopsy in patients with a history of malignant lymphoma.

Efficacy and safety of coaxial transthoracic fine-needle biopsy were evaluated in 54 patients with a history of malignant lymphoma and new chest lesions. Twenty-one patients had recurrent lymphoma. Correct diagnosis was made in 17 of the 21 patients (81%) after one biopsy. The sensitivity increased to 95% with repeat needle biopsy in three patients. Immunophenotyping (determining phenotype by means of immunologic examination) was essential for a definitive diagnosis of lymphoma in three patients. Non-lymphomatous malignancies were correctly diagnosed in 14 patients. An infectious organism was identified in 11 of 19 patients (58%) with benign lesions. Pneumothorax occurred in eight patients (15%), necessitating placement of a chest tube in two (4%). Mild hemoptysis was observed in four patients (7%). The authors conclude that coaxial transthoracic fine-needle biopsy in patients with a history of lymphoma is safe and accurate. The use of large cutting needles or surgical biopsy can be restricted to patients with false-negative findings at percutaneous biopsy and to patients in whom histologic transformation of lymphoma is suspected.

Adult↗
PubMed1992

CT angiography with spiral CT and maximum intensity projection.

The authors describe a technique for obtaining angiographic images by means of spiral computed tomography (CT), preprocessing of reconstructed three-dimensional sections to suppress bone, and maximum intensity projection. The technique has some limitations, but preliminary results in 48 patients have shown excellent anatomic correlation with conventional angiography in studies of the abdomen, the circle of Willis in the brain, and the extracranial carotid arteries. With continued development and evaluation, CT angiography may prove useful as a screening tool or replacement for conventional angiography in some patients.

Abdomen↗
PubMed1991

Palmaz stent in atherosclerotic stenoses involving the ostia of the renal arteries: preliminary report of a multicenter study.

Palmaz balloon-expandable stents were placed in 28 hypertensive patients with atherosclerosis involving the ostia of the renal arteries. Stents were placed to treat elastic recoil immediately after conventional angioplasty in 20 patients and restenosis after percutaneous transluminal angioplasty in eight patients. Technical success (greater than 30% residual stenosis) was achieved in 27 patients. Complications occurred in five patients. At follow-up (1-25 months), hypertension was cured in three patients and improved in 15 patients, with a cumulative cure or improvement of 64% at 6 months. Of 14 patients with a serum creatinine level of 1.5 mg/dL (132.6 mumol/L) or greater before the placement of stents, five demonstrated improved renal function, five showed stabilization of their condition, and four demonstrated deterioration. Follow-up angiography (2-18 months) was performed in 18 patients. Restenosis was present in seven patients and was accompanied by a relapse of hypertension in only three patients. Of the other four patients with restenosis, two had no initial improvement and two had an initial response without a relapse of hypertension. In this preliminary study, renal stents were beneficial in many patients with poor results from conventional angioplasty for ostial atheroma.

Aged↗
PubMed1991

Intravascular ultrasound.

The recent development and rapid expansion of new percutaneous vascular interventional devices designed to remove or remodel atherosclerotic plaque has been accompanied by equally strong interest in imaging modalities guidance systems to more accurately evaluate disease and better facilitate vascular interventions than traditional angiography. Although contrast angiography remains the standard for diagnostic evaluation of coronary and peripheral arteries, intravascular ultrasound has the potential to offer more precise information about vascular anatomy and disease. Intravascular ultrasonography has been able to provide specific information regarding vessel lumen and wall. Such information is not available by traditional diagnostic methods and may become essential in the future diagnosis, staging, and treatment of atherosclerosis.

Blood Vessels↗
PubMed1990

Directional atherectomy in the treatment of stenotic dialysis access fistulas.

Directional atherectomy has proved useful in the treatment of peripheral vascular occlusive disease, and the authors have begun using this modality in the treatment of patients with failing hemodialysis access fistulas. The authors describe their initial experience with 13 patients in whom directional atherectomy was used to treat stenotic hemodialysis fistulas. Directional atherectomy was the sole treatment modality for eight patients. Three patients underwent atherectomy after unsuccessful percutaneous transluminal angioplasty (PTA). In two patients, unsuccessful atherectomy necessitated subsequent PTA. Directional atherectomy was successful in 10 of 13 patients. In seven of these 10 patients who are still alive, the dialysis fistulas remain patent. Directional atherectomy is a safe and useful technique in the percutaneous treatment of hemodialysis fistula stenosis. Early data indicate patency rates that may be higher than those reported with PTA.

Arteriosclerosis↗
PubMed1990

The cause of superior vena cava syndrome: diagnosis with percutaneous atherectomy.

The cause of superior vena cava syndrome (SVCS) in two patients was identified by means of endovascular biopsy of the superior vena cava (SVC) performed with a percutaneous atherectomy catheter. In both cases, the extracted tissues were neoplastic, therefore obviating additional invasive procedures. After a specific diagnosis was established, external-beam radiation therapy was used to treat the SVCS. The atherectomy catheter was used in conjunction with other percutaneous techniques, including balloon angioplasty and endovascular stenting of the SVC.

Adenocarcinoma↗
PubMed1989

Noncoronary angioplasty.

PTA is an established method of revascularization in a variety of medical conditions. It is performed for specific morphologic and clinical indications. PTA is the procedure of choice in Fontaine stage IIB through IV lower extremity ischemia due to iliac and/or femoropopliteal stenosis or short occlusion. Its role is less certain in infrapopliteal disease, although current studies have begun to establish long-term effectiveness. PTA is the procedure of choice for renal revascularization in renovascular hypertension due to fibromuscular disease or non-ostial atherosclerosis, selected cases of renal artery stenosis associated with renal insufficiency, and transplant renal artery stenosis. It is also useful in treating the renovascular component of complex hypertension and may be indicated in severe renal artery stenosis (75%-99%), even in the absence of clinically demonstrable RVHTN. PTA has limited applications in the venous system and only short-term success in the treatment of stenoses in dialysis access fistulas. PTA often serves as an important adjunct to surgical revascularization by providing improved inflow or outflow. PTA is the procedure of choice when anatomically feasible in subclavian steal syndrome. The role of PTA in carotid artery disease, particularly atheromatous disease of the internal carotid artery, is uncertain. The same may be said of PTA for vertebral artery stenosis, although the overwhelming majority of vertebral artery stenoses are morphologically suitable for PTA. PTA and surgery are both effective in the treatment of abdominal angina. There are more data available to verify the long-term patency of thromboendarterectomy and bypass grafts than PTA for mesenteric ischemia. However, since the technical success for PTA is high and since coronary co-morbidity is the most common cause of perioperative mortality in surgical series, PTA should be seriously considered as the procedure of first choice. Serious complications of PTA occur in approximately 5% of cases. Two to three percent of PTA patients have complications requiring surgery or causing a prolongation or alteration of hospital course. The morbidity, mortality, and cost associated with PTA are low. The discomfort is minor, and postprocedural recovery rapid. The major limitations of PTA include its unsuitability for some lesions (long-segment occlusions and stenoses, orifice lesions, eccentric lesions) and postangioplasty restenosis. These problems are being addressed by ongoing laboratory and clinical research. In the near future, it is likely that endoluminal transmural sonography of the vessel wall will help guide our interventions.

Angioplasty, Balloon↗
PubMed1989

Developing an interventional radiology practice in a community hospital: the interventional radiologist as an equal partner in patient care.

Development of an interventional radiology practice or section depends first on the commitment and ability of the interventionalist but is also contingent on an appropriate environment. Moreover, the interventionalist must attempt to change long-standing concepts and referral patterns with aggressive dissemination of information. He or she must be an advocate of the procedures offered, as well as their benefits to the patient and the health care system. One must actively include outpatient visits and admissions as part of services offered. Allies in this effort include primary care physicians, internists, hospital administration, and third-party payers. In addition, organized radiology can now offer some assistance through the Society of Cardiovascular and Interventional Radiology and the American College of Radiology. All of these factors will contribute significantly to the success of interventional radiology in both teaching and community hospital settings.

Hospital Departments↗
PubMed1989

Blue toe syndrome: treatment with percutaneous atherectomy.

"Blue toe syndrome" refers to digital ischemia of the foot in the presence of palpable or Doppler audible pedal pulses. This clinical syndrome is caused by microembolization to small vessels from a proximal source. The use of percutaneous transluminal atherectomy is described in the treatment of embologenic superficial femoral artery lesions in seven patients. All seven had prompt healing of the ischemic toes, and none required surgical revascularization or amputation. One patient developed a recurrent stenosis at the atherectomy site and had a second episode of digital ischemia, which was treated by means of atherectomy with a larger device. Histologic study of atherectomy specimens suggests that emboli arise from adherent fibrinoplatelet aggregates or thrombus and less often from cholesterol-rich atheromatous plaque. Although either percutaneous transluminal angioplasty or atherectomy can be used to treat the underlying stenosis, percutaneous atherectomy offers the advantage of nonsurgical removal of embologenic material and provides material for histologic study. Percutaneous atherectomy is an effective method of treating embologenic superficial femoral stenoses in patients with ipsilateral blue toe syndrome.

Adult↗
PubMed1988

Gallium uptake in the thyroid gland in amiodarone-induced hyperthyroidism.

Amiodarone is an iodinated antiarrhythmic agent that is effective in the treatment of atrial and ventricular arrhythmias. A number of side effects are seen, including pulmonary toxicity and thyroid dysfunction. A patient with both amiodarone-induced pneumonitis and hyperthyroidism who exhibited abnormal gallium activity in the lungs, as well as diffuse gallium uptake in the thyroid gland is presented. The latter has not been previously reported and supports the concept of iodide-induced "thyroiditis" with gallium uptake reflecting the inflammatory response.

Amiodarone↗
PubMed1986

Pyogenic abscess of the medulla oblongata.

Pyogenic brain stem abscess is rare. A case of spontaneous abscess of the medulla oblongata is reported in which the diagnosis was made preoperatively by computed tomography. Surgical drainage resulted in good functional recovery and radiological resolution of the lesion. This is the first reported case of survival in a patient with an abscess of the medulla oblongata. The pathophysiology, clinical symptoms, and radiological appearance of the entity are discussed. Prompt diagnosis and drainage are emphasized as important factors influencing survival.

Aged↗
PubMed1986

CT of extraarachnoid metrizamide instillation.

Because CT of spinal extraarachnoid metrizamide collections may be misleading, we reviewed the postmetrizamide CT scans of 425 patients in order to characterize the appearance of subdural or epidural metrizamide. Eight patients were found to have extraarachnoid metrizamide contrast collections. In all patients, both the subarachnoid space and the extraarachnoid collection were opacified with metrizamide. In seven patients, a subdural collection of metrizamide created a mass upon the opacified subarachnoid space. Three of these subdural collections were less dense than the opacified subarachnoid compartment and simulated soft-tissue disease, including tumor and an arteriovenous malformation. The hypodense collections are probably a result of leakage of metrizamide and cerebrospinal fluid through the spinal needle defect. CT clues for diagnosing these potentially misleading subdural collections include preservation of the normal dural and epidural interface, identification of small islands of metrizamide within a suspected soft-tissue "mass," the presence of concomitant epidural contrast material collections, and the absence of adjacent vertebral-body destruction.

Epidural Space↗
PubMed1985

Electron microscopic demonstration of lysosomal inclusion bodies in lung, liver, lymph nodes, and blood leukocytes of patients with amiodarone pulmonary toxicity.

The mechanism of amiodarone-induced pulmonary toxicity is unknown. Two cases of amiodarone pulmonary toxicity are presented in which abnormal inclusion bodies containing whorls of membrane were seen on electron microscopy of extrapulmonary tissues. These cytoplasmic lysosomal inclusion bodies were observed in lymphocytes, plasma cells, granulocytes, tissue macrophages, and hepatocytes. These widespread histopathologic changes in extrapulmonary tissues and in a variety of cell types are similar to more extensively investigated findings in animal models that are thought to represent a drug-induced lysosomal storage disease, phospholipidosis.

Amiodarone↗