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Biomedical subjects

C M Mehringer

Publications and source records attributed to C M Mehringer.

At least 19 recordsLinked to original sources
PubMed1992

Neuropsychological correlates of white-matter lesions in healthy elderly subjects. A threshold effect.

The clinical significance of white-matter lesions (WMLs) detected by computed tomography and magnetic resonance imaging in healthy elderly subjects has been controversial, with some studies reporting associated deficits in cognition and others failing to document cognitive disturbance. In our sample of 100 healthy elderly individuals, almost half (n = 46) had no WMLs, approximately one fourth had minimal (less than or equal to 1 cm2; n = 27) or moderate (greater than 1 cm2 but less than or equal to 10 cm2; n = 21) WML areas, and six subjects had large WML areas (greater than 10 cm2). Substantial disturbances in basic attention and selected frontal lobe skills were detected in the six subjects with the large WML areas. These findings suggest that a "threshold" of WML area must be present before cognitive deficits are observed. Surprisingly, no significant relationships between duration of hypertension or cholesterol levels and WMLs were detected, suggesting that factors other than vascular disturbances are involved in the origin of at least some WMLs.

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PubMed1992

Sequential intraluminal ultrasound evaluation of balloon angioplasty of an iliac artery lesion.

This report describes intravascular ultrasound imaging of a localized 81% stenosis in the left common iliac artery of a 52-year-old woman. The lesion was dilated using an 8 mm balloon and was imaged pre- and post-dilation using arteriography and a 5F, 30 Mhz intravascular ultrasound catheter. The same site was imaged again intraoperatively at two months following the initial procedure using an 8F, 20 Mhz intravascular ultrasound catheter when the patient had a femoropopliteal bypass for continuing ischemia. Intravascular ultrasound imaging allowed accurate, sequential, on-line calculation of the cross-sectional area and volume of the lesion both, acutely and following healing of the site. The morphology of the fractured arterial plaque was clearly defined, demonstrating distribution of calcification, and intraluminal flaps not apparent on arteriography. The case demonstrates the unique potential of intravascular ultrasound in assessing the immediate effect of interventions and evaluating the long-term healing.

Angioplasty, Balloon↗
PubMed1992

A quantitative MRI study of vascular dementia.

We studied the MRI and clinical factors associated with dementia following stroke by quantifying ventricle-to-brain ratio (VBR), anatomic region of infarction, and cortical, subcortical, and white matter areas of infarction in 24 stroke patients with dementia and 29 nondemented stroke patients. The factors that most strongly correlated with dementia were total white matter lesion (WML) area, left WML, VBR, right WML, age, left cortical infarction area, left parietal infarction area, and total infarction area. Using discriminant analysis, these factors correctly classified 28 of 29 nondemented patients and 18 of 24 demented patients. Both cortical and white matter total infarction area measurements were strongly associated with dementia in stroke patients, suggesting that these factors strongly influenced the development of dementia following stroke. There was a strong association between dementia and left- but not right-hemisphere infarction area. The only demographic factor that strongly associated with dementia was age.

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PubMed1991

Intravascular ultrasound imaging of an acute dissecting aortic aneurysm: a case report.

A case of acute dissecting aortic aneurysm is described in which intravascular ultrasonography was used at the time of aortography to produce real-time, 360 degree cross-sectional images of the aorta. The transmural vessel morphology visualized by this new catheter-based technology allowed confirmation of the diagnosis and identification of distal extension to the aortic bifurcation. The case demonstrates the unique potential of this modality in diagnosis and possible therapy in vascular diseases.

Acute Disease↗
PubMed1991

Brain lesions and cognitive function in late-life psychosis.

Twenty-four patients who developed their first psychotic episode after the age of 45 were studied with MRI and comprehensive neuropsychological testing and compared with 72 healthy elderly subjects. The patients demonstrated more clinical abnormalities on MRI, were more likely to have large white-matter lesions or metabolic illness, and did more poorly on many neuropsychological tests, particularly those testing frontal-lobe and memory abilities. We conclude that structural brain injury is commonly associated with the late onset of psychosis. Neuroimaging investigations are a valuable component in the evaluation of this patient group.

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PubMed1991

Frontal lobe degeneration: clinical, neuropsychological, and SPECT characteristics.

The clinical, neuropsychological, and cerebral blood flow characteristics of eight patients with frontal lobe degeneration (FLD) were studied. Social withdrawal and behavioral disinhibition were the earliest and most common clinical presentations, and psychiatric symptoms typically preceded the onset of dementia by several years. Neuropsychological testing showed selective impairment of frontal and memory tasks with relative sparing of attention, language, and visuospatial skills. Single-photon emission computerized tomography demonstrated frontal and temporal hypoperfusion with relative sparing of parietal and occipital blood flow. Previous studies suggest that the neuropathologic findings in patients with FLD are varied; some demonstrate frontal gliosis, neuronal loss, and Pick bodies while others show only gliosis and neuronal loss.

Aged↗
PubMed1991

An analysis of cerebral blood flow in acute closed-head injury using technetium-99m-HMPAO SPECT and computed tomography.

Technetium-99m-hexamethylpropyleneamine (HMPAO) SPECT and x-ray CT were compared in 15 patients with acute closed-head injury. There were 44 focal lesions in all. Fifteen (34%) lesions were seen on both x-ray and SPECT. Seventeen (39%) lesions were seen only on SPECT. Twelve (27%) of the lesions were seen on x-ray tomography only. Of the lesions seen on x-ray tomography but not on SPECT, two were subarachnoid hemorrhage, two were thin subdural hematomas, and eight were contusions. This study shows that SPECT can detect focal disturbances of cerebral blood flow that are not seen on x-ray tomography. It also suggests that there are two types of contusions: those with a decreased cerebral blood flow (i.e., detectable on SPECT) and those with a cerebral blood flow equal to that of the surrounding brain.

Acute Disease↗
PubMed1990

Correlation between penile angiography and duplex scanning of cavernous arteries in impotent men.

During the diagnostic evaluation of patients with vasculogenic impotence duplex scanning has been proposed as a reliable noninvasive method to evaluate the cavernous arteries. However, the sensitivity and specificity of this test have never been elucidated. To provide insight into the clinical value of this test 25 men who presented with impotence and failed to respond to 60 mg. intracavernous papaverine were evaluated with duplex scanning and the results of this modality were compared to penile angiography. The cavernous arteries were considered normal by duplex scanning if the artery demonstrated either a 60% or greater increase in diameter and/or a peak flow velocity of greater than 25 cm. per second 5 minutes after papaverine injection. Penile angiography was considered normal if both cavernous arteries were visualized and appeared to be normal radiographically (after intracorporeal papaverine). In the 25 patients studied there was no significant difference in peak flow velocity between patients with normal or abnormal cavernous arteries by angiography. In addition, arterial dilatation (more than 60%) after papaverine injection did not correlate with the results of the angiogram. These data demonstrate that duplex scanning of the cavernous arteries does not correlate well with what is observed by penile angiography in a selected population of men with vasculogenic erectile dysfunction. Since penile angiography itself has limitations in the evaluation of the penile arteries, the reliability of duplex scanning to identify cavernous artery dysfunction needs additional confirmation.

Adult↗
PubMed1990

Endovascular occlusive intervention in the management of trauma.

This report summarizes a 10-year experience (1978-1987) in a metropolitan hospital with 102 patients sustaining a variety of complex or inaccessible vascular injuries. Management included the application of occlusive interventional arteriographic techniques. Regional injuries included head and neck (56%), trunk (13%), and extremity (32%). Techniques of vascular occlusion were often performed in conjunction with the initial arteriographic evaluation and were comprised of particulate embolization (42%), placement of mechanical devices (36%), or tissue adhesives (1%), or a combination (21%). There were no deaths in this series and the only complications included four cases of dislodgement of the occlusive agent. We demonstrate that endovascular occlusion is a useful, safe and efficacious procedure in selected patients with complex, inaccessible or life-threatening vascular trauma.

Adolescent↗
PubMed1989

Anatomy of penile venous drainage in potent and impotent men during cavernosography.

Recent data suggest that approximately 80 per cent of the men with vasculogenic impotence have evidence of failure to store blood (venous leakage) within the corpora cavernosa. To identify the venous channels into which corporeal blood drains in impotent men, we performed cavernosograms after intracorporeal injection of papaverine in 44 consecutive men presenting with erectile dysfunction and these were compared to studies in 10 potent men. The cavernosograms were examined for evidence of venous drainage from the penis and the site of leakage was identified. It was determined that among the impotent population with vasculogenic impotence 37 of 40 evaluable men (92.5 per cent) demonstrated contrast medium in the venous system draining the penis: the deep dorsal vein was visualized in 55 per cent, proximal cavernosal and crural veins in 55 per cent, deep dorsal and proximal veins in 22.5 per cent and corpus spongiosum in 25 per cent. Only 2 of the 10 potent men demonstrated contrast medium in the venous channels draining the penis. From these observations we conclude that in men suspected of having venogenic impotence identification of the drainage vessels by cavernosography appears to be important in planning any surgical approach to occlude these veins. However, the finding of a venous leak by cavernosography must not be considered a sine qua non diagnosis of venogenic impotence, since a certain percentage of potent men will demonstrate this radiographic finding.

Adult↗
PubMed1989

Interventional neurovascular treatment of traumatic carotid and vertebral artery lesions: results in 234 cases.

Traumatic injuries to the head and neck that result in arteriovenous fistulae are often difficult to treat by direct surgical access. This is because of anatomic location, instability of the acutely injured patient, and difficulty in localizing the exact site of injury. Between 1974 and 1988, 234 consecutive cases of traumatic injuries to the carotid or vertebral artery were evaluated by our group for intravascular embolization therapy. This included 206 cases of direct and seven cases of indirect carotid-cavernous sinus fistulae and 21 cases of traumatic vertebral fistulae. A variety of devices including detachable balloons, liquid tissue adhesives, microcoils, and silk suture were used with the goal of fistula occlusion and preservation of the parent vessel. This was achieved in 193 cases (82%). In the remaining 41 cases (18%), the carotid or vertebral artery had to be occluded by endovascular occlusion techniques because of extensive vascular injury in 28 cases and subtotal occlusion of the fistula in 13 cases. Complications included transient cerebral ischemia in six cases, pseudoaneurysm formation in five cases, stroke in five cases, and peripheral nerve injury in one case. The development of interventional neurovascular techniques has altered the management of these acutely injured patients. The preferred method for treatment has shifted from direct surgical access under general anesthesia to endovascular therapy under local anesthesia.

Adolescent↗
PubMed1988

Preoperative splenic artery occlusion as an adjunct for high risk splenectomy.

High risk splenectomy is often encountered in cases of hypersplenism with massive splenomegaly (10 times usual weight of 150-200 g) resulting from myelophthisic processes. Intra-operative ligation of the splenic artery through the lesser sac is a technically useful method of gaining vascular control prior to mobilizing the challenging spleen. However, a massive or inaccessible spleen imposes mechanical limitations during surgery and may be complicated by torrential intra-operative hemorrhage in the setting of severe thrombocytopenia refractile to platelet transfusions. The authors describe pre-operative intravascular proximal splenic artery control in four adult patients (3 men, 1 woman) with extreme splenomegaly (2,250-10,000 g). The massive splenomegaly in this group resulted from chronic myelogenous leukemia (n = 2), isolated splenic lymphoma (n = 1), and agnogenic myeloid metaplasia (n = 1). Chief symptom manifestations included left upper quadrant abdominal pain, early satiety, post-prandial emesis, dyspnea, petechiae, and associated easy bruising. Prior to surgery, all the patients were taken to the radiology suite where either detachable silastic balloons or stainless steel coils were placed selectively into the splenic artery under fluoroscopic guidance requiring approximately 35 minutes. Splenic artery occlusion aided normalization of thrombocytopenia (average increases 19,000/microliter to 215,000/microliter) with prolongation in survival of platelets. Successful splenectomy was subsequently performed with no additional transfusion requirements and was made technically easier by reducing splenic bulk. There were no adverse consequences of intravascular occlusion and no peri-operative morbidity or mortality. Preoperative intravascular selective splenic artery occlusion, used as an important potential adjunct to anticipated high risk splenectomy, is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Treatment of impending carotid rupture with detachable balloon embolization.

Acute carotid artery rupture is frequently heralded by prodromal arterial bleeding. This warning signal provides the physician with a brief interval in which to hemodynamically stabilize a patient, electively occlude the carotid, and consequently improve the patient's chance of survival. For three years, we have employed an initial nonoperative approach to patients with impending carotid rupture. A trial of endovascular balloon occlusion followed by detachable balloon embolization of the carotid artery has been utilized. Patients unable to tolerate temporary occlusion underwent a vascular bypass procedure followed by embolization. Six patients have undergone this approach, and all had permanent cessation of bleeding. None died as a result of the procedures. One patient developed permanent neurologic deficits. Balloon embolization offers improved results over elective ligation and should be considered as an alternative treatment for patients in this dire predicament.

Adult↗
PubMed1986

Spontaneous arteriovenous fistulas of cerebral vessels in association with fibromuscular dysplasia.

Four cases of spontaneous arteriovenous fistula seen in association with fibromuscular dysplasia of the parent artery are presented. In two patients, the fistula was between the carotid artery and cavernous sinus; in two others, the fistula involved the vertebral artery and paravertebral veins. It is postulated that the angiopathy was responsible for the fistula. Treatment by detachable balloon embolization was successful in each case; however, the presence of the fibromuscular dysplasia made treatment more difficult.

Adult↗
PubMed1986

Treatment of direct carotid cavernous sinus fistulae. Various therapeutic approaches and results in 148 cases.

From 1974 to 1986, 148 patients with carotid cavernous fistula (CCF) were evaluated for intravascular therapy. Four patients died from hemorrhage before treatment could be instituted and the CCF closed spontaneously in 5. Therapeutic approaches which resulted in complete occlusion in the remaining 139 cases were transarterial in 118, transvenous in 15 and external compression of the carotid artery and jugular vein in 6. The current treatment of choice of the direct CCF is intravascular embolization using detachable balloons, particulate emboli or liquid adhesive agents to occlude the CCF while attempting to preserve the carotid artery. In 15 patients it was technically too difficult to use the transarterial approach. The patients were therefore treated from a transvenous approach including access via the femoral vein, superior ophthalmic vein, intraoperatively from the inferior petrosal sinus or direct puncture of the cavernous sinus. Embolic agents used included detachable silicone balloons, steel minicoils, particulate emboli and isobutyl-2-cyanoacrylate. In 14 of these 15 patients total obliteration was achieved with marked improvement in symptoms. Complications occurred in 3 patients including perforation of the cavernous sinus resulting in subarachnoid hemorrhage, delayed pontine hemorrhage from subtotal occlusion of the fistula and transient increased proptosis.

Arteriovenous Fistula↗
PubMed1985

Computerized tomography of the foramen magnum: achondroplastic values compared to normal standards.

Computerized tomographic dimensions of the foramen magnum of 63 achondroplastic individuals were compared to standards established for nonachondroplastic individuals. The size of the foramen magnum in patients with achondroplasia was small at all ages, particularly in those with serious neurologic problems. The data suggest that measurement of the foramen magnum may identify achondroplastic individuals at high risk of developing neurologic complications.

Achondroplasia↗
PubMed1984

Superiority of transcutaneous oximetry in noninvasive vascular diagnosis in patients with diabetes.

Transcutaneous oxygen tension Ptco2 is directly related to skin oxygen delivery. Regional transcutaneous oximetry ( RTO ) compares peripheral and truncal (Ptco2), yielding a regional perfusion index indicative of local limb perfusion. The relative diagnostic values of RTO , Doppler ankle-brachial pressure ratio (ABR), pulse volume recording (PVR), and toe pulse reappearance time (PRT/2) were studied in 64 limbs of patients with diabetes. These limbs were clinically classifiable into claudication, rest pain, and gangrene groups. Regional transcutaneous oximetry had a higher diagnostic accuracy than ABR (X2 = 27.47, P less than .001), PVR (X2 = 7.54, P less than .01), and PRT/2 (X2 = 10.99, P less than .001). Regional transcutaneous oximetry was universally applicable and the degree of hypoxia observed correlated with clinical symptoms. Significant hypoxia predicted large-vessel angiographic lesions, many of which were reconstructible . Regional transcutaneous oximetry should be the initial noninvasive test in diabetic peripheral vascular disease.

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