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Biomedical subjects

G Leinsinger

Publications and source records attributed to G Leinsinger.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Magnetic resonance imaging of benign and premalignant tumors in childhood].

PURPOSE: To evaluate the potential of MRI in determining benign and premalignant abdominal tumors in childhood. METHODS: MR images of 93 children with 69 malignant and 24 benign abdominal tumors were analyzed retrospectively without and with knowledge of clinical findings. Based on the final diagnosis, MR findings were surveyed with regard to the correct differential diagnosis and to the differentiation between benign and malignant masses. RESULTS: Analysis of MRI alone revealed relatively low sensitivity of 67% for diagnosis of a benign tumor. The main reason was unspecific morphologic criteria leading to the false-negative diagnosis of a malignant tumor. Together with clinical and laboratory findings, sensitivity could be increased to 92%. The main criterion for differentiation of malignant tumors turned to be out the origin of tumor. Benign tumors could be best differentiated by their internal structure. CONCLUSION: When considering clinical findings in pediatric abdominal tumors, MRI represents a valuable modality for differential diagnosis.

Abdominal Neoplasms↗
PubMed1999

Corpus callosum size in schizophrenia--a magnetic resonance imaging analysis.

Previous MRI studies have shown differences in corpus callosum size between schizophrenic patients and controls. The corpus callosum (CC), as the main interhemispheric fiber tract, plays an important role in interhemispheric integration and communication. Though MRI studies suggest smaller CC in schizophrenia, there are still conflicting findings. Using in vivo magnetic resonance imaging, it was investigated whether the midsagittal area of CC differs between twenty-three right-handed male schizophrenic patients and twenty-three matched controls. Total CC area, five subregions of CC, total brain volume, gray and white matter were measured. No differences between schizophrenic patients and controls were found regarding all CC measurements, total brain volume, and gray matter tissue. However, a significant reduction of white matter tissue in the patient group emerged. There was no correlation between CC morphology and clinical variables such as age of onset, length of illness or symptom severity. Interestingly, five schizophrenic patients with a positive family history of schizophrenia showed significant reduction of the subregion C3, associated with a reduced total brain and gray and white matter volume. Significant reduction in the CC and its subregions was not confirmed in this group of patients with schizophrenia. In the subgroup of schizophrenic patients with a positive family history of schizophrenia, a significant reduction of the subregion corresponding to a part of the trunk of the CC was found.

Adult↗
PubMed1999

MR angiography versus color Doppler sonography in the evaluation of renal vessels and the inferior vena cava in abdominal masses of pediatric patients.

OBJECTIVE: Involvement of renal vessels and the inferior vena cava (IVC) plays a decisive role during operative planning for removal of abdominal masses in pediatric patients. Advantages and limitations of MR angiography and color Doppler sonography for determining these factors were evaluated. MATERIALS AND METHODS: MR angiography and color Doppler sonography were performed preoperatively in 42 neonates, infants, and children with abdominal masses and were compared with spin-echo MR imaging and with surgical findings. Variables evaluated were anatomic variants, vessel displacement, patency of vessels, collateral circulation, and intravascular tumor extension. Quality of vessel visualization was assessed in vessels not affected by tumor. RESULTS: In 88% of unaffected renal vessels, the entire vessel course could be visualized on MR angiography compared with 58% on color Doppler sonography and 43% on spin-echo MR imaging. In four of nine cases, color Doppler sonography revealed an accessory renal artery, whereas MR angiography revealed these variants in seven of nine cases. MR angiography showed 79% and color Doppler sonography 66% of displaced vessels. Unlike MR angiography, color Doppler sonography did not reveal five stenotic renal veins because they could not be completely imaged. In two cases, however, MR angiography falsely indicated an occlusion of the IVC, whereas color Doppler sonography showed residual flow. CONCLUSION: Anatomic variants, vessel displacement, collateral circulation, and neoplastic vessel infiltration were revealed more accurately by MR angiography than by color Doppler sonography. In cases in which patency of the IVC is unclear on MR angiography, color Doppler sonography should also be performed.

Abdominal Neoplasms↗
PubMed1995

[The diagnostic value of digital and conventional imaging in intravenous urography].

PURPOSE: To compare image quality of digital luminescence radiography with conventional film-screen techniques during excretion urography. Four field tests and ROC analysis for determining diagnostic value. MATERIAL AND METHOD: 135 patients were included in a prospective study. Three independent observers judged the five minute (59 cases) or ten minute (76 cases) films after contrast injection using digital images as well as corresponding conventional images (five minutes-76 cases, ten minutes-59 cases). RESULTS: The digital technique provided better information concerning the renal parenchyma, the soft tissues and bone structures. Contrast enhanced detail was demonstrated equally well by both systems. The two systems had similar sensitivity but digital radiography showed higher specificity.

Adolescent↗
PubMed1994

STA-MCA bypass in bilateral carotid artery occlusion: clinical results and long-term effect on cerebrovascular reserve capacity.

In this report we describe our experience with extracranial-intracranial arterial bypass surgery in a subgroup of 9 patients (mean age at surgery 61 +/- 9 years) with bilateral carotid artery occlusion, unilaterally symptomatic for occlusive cerebrovascular disease of haemodynamic origin. Haemodynamic insufficiency is characterized by a severely reduced cerebrovascular reserve capacity, measured with Xe-133 D-SPECT and acetazolamide challenge. Preoperatively, the mean baseline cerebral blood flow of 54 +/- 6 ml 100 g-1 min-1 did not change after challenge (54 +/- 5 ml 100 g-1 min-1) in the symptomatic hemisphere. Immediately following surgery an improvement in cerebrovascular reserve capacity for up to 14 +/- 8 ml 100 g-1 min-1 (1-2 years control) was noted. One patient subsequently died from a perioperative stroke, another patient died three months post-operatively from a myocardial infarction. Three patients were followed up to 4 years, four for 2 years. Patients with former transient ischaemic attacks had no further attacks, symptoms from PRIND or minor stroke did not progress further, nor did new symptoms occur. Unilateral extracranial-intracranial bypass surgery has a positive effect on clinical outcome in highly selected patients with bilateral carotid artery occlusion and cerebral ischaemia of haemodynamic origin.

Adult↗
PubMed1994

Improvement of cerebrovascular reserve capacity by EC-IC arterial bypass surgery in patients with ICA occlusion and hemodynamic cerebral ischemia.

Since the negative results of the international Bypass Study, extracranial-intracranial (EC-IC) bypass surgery is infrequently employed in the treatment of patients with cerebral ischemia. Newly acquired evidence concerning the pathophysiology of cerebral ischemia, however, has facilitated the identification of a small subgroup of patients with "hemodynamic" cerebral ischemia. Characteristically, these patients demonstrate severely impaired cerebrovascular reserve capacity due to occlusive disease and insufficient collateral blood supply. Over an 8-year period, 28 patients were defined by clinical and laboratory criteria as suffering from hemodynamic cerebral ischemia. All patients had recurring episodes of focal cerebral ischemia due to unilateral internal carotid artery occlusion. Computerized tomography (CT) scans either were normal or showed evidence of border zone infarction. The cerebrovascular reserve capacity was studied using 133Xe single-photon emission CT and acetazolamide challenge and was found to be significantly impaired in all patients. Based on these criteria, superficial temporal artery-middle cerebral artery anastomosis was performed to augment collateral flow to the ischemic hemispheres. Two patients died from myocardial infarction, one 4 days and the other 2 months postoperatively. One patient died from massive brain infarction and another suffered a postoperative stroke with incomplete recovery, resulting in a major morbidity and mortality rate of 14%. Minor morbidity included one patient with a subdural hematoma who subsequently recovered completely. The postoperative course was uneventful in 23 patients (82%). Over a mean follow-up period of almost 3 years, no patient had another episode of brain ischemia. Bypass patency was confirmed by postoperative angiography in 26 patients. Follow-up studies of cerebral blood flow (CBF) and cerebrovascular reserve capacity showed significant improvement of the latter while the resting CBF was essentially unchanged. In view of these findings, the authors conclude that EC-IC bypass surgery constitutes appropriate therapy for a subgroup of patients with recurrent focal cerebral ischemia, defined using the strict selection criteria employed in this study.

Adult↗
PubMed1994

Diagnosis of osteomyelitis. Accuracy and limitations of antigranulocyte antibody imaging compared to three-phase bone scan.

Thirty-seven patients with suspected osteomyelitis in conjunction with diabetic gangrene (N = 14, group 1), arthroplasty (N = 8, group 2), and various diseases (N = 15, group 3) were examined. Three-phase bone scans, followed by granulocyte imaging using I-123 labeled anti-NCA 95 monoclonal antibodies, were performed to evaluate and compare the diagnostic accuracy of both procedures. Final diagnosis was established histologically, bacteriologically, or by both methods either through the clinical course or by long-term follow-up in patients in group 1. Osteomyelitis was proven in 17 out of the 37 patients. Bone and antigranulocyte imaging demonstrated positive results in all patients with osteomyelitis (sensitivity 100% for each method). No signs of skeletal infection were found in 20 patients. Fifteen of these patients had no antigranulocyte antibody accumulation, resulting in 75% specificity. Ten patients without infection had normal three-phase bone imaging results (specificity 50%). Antigranulocyte imaging results were negative in 6 out of 10 patients without osteomyelitis in groups 2 and 3 whose bone imaging results were questionable. However, because of identical bone and granulocyte imaging results, no increase of diagnostic accuracy could be obtained by additional granulocyte imaging in patients with diabetic gangrene. Final diagnoses of false-positive antigranulocyte studies were aseptic osteonecrosis (N = 2), loosening of prostheses, gouty arthritis, and pain after arthrolysis. In summary, antigranulocyte antibody imaging offered high sensitivity and acceptable specificity for the diagnosis of osteomyelitis. Diagnostic accuracy can be improved through the adjuvant use of antigranulocyte imaging for patients with suspected osteomyelitis, especially when radiographic and scintigraphic results are questionable or unreliable.

Adult↗
PubMed1994

Normal values of cerebrovascular reserve capacity after stimulation with acetazolamide measured by xenon 133 single-photon emission CT.

PURPOSE: To determine whether a standardized stimulation challenge with acetazolamide will be helpful for assessing the vasodilatory capacity in patients with obstructive cerebrovascular disease. METHODS: To establish normative data of the cerebrovascular reserve capacity, a group of 41 control patients was investigated. The regional cerebral blood flow was measured quantitatively before and after stimulation with acetazolamide using the xenon 133 inhalation method and dynamic single-photon emission CT. RESULTS: A significant increase of regional cerebral blood flow was found after administration of 1 g of acetazolamide. By doubling the dose no significant further increase was measured. We found no correlation of either baseline or stimulated flow values with age. However, a linear dependence between the stimulated flow values and their respective baseline values was observed. CONCLUSION: The standardized challenge with acetazolamide seems to be a reliable method to determine cerebrovascular reserve capacity quantitatively.

Acetazolamide↗
PubMed1992

Immunoimaging of choroidal melanoma: assessment of its diagnostic accuracy and limitations in 101 cases.

Immunoscintigraphy (IS) was performed on 101 patients with space occupying intraocular lesions including choroidal melanomas (85), choroidal naevi (11), non-melanoma metastases (three), and other melanoma simulating lesions (two). Scintigraphic images with conventional and emission computer tomography techniques were obtained after the intravenous injection of 99mTc-labelled F(ab')2 fragments of monoclonal antibody (MoAb) 225.28S directed against the high molecular weight-melanoma associated antigen (HMW-MAA). Immunohistochemistry was performed on sections of four out of 10 melanoma-containing eyes to confirm MoAb binding. IS demonstrated positive scans in 66 out of 85 choroidal melanomas, offering a sensitivity of 78%. Sensitivity was dependent on the lesion size. True negative results were obtained in 15 out of 16 non-melanoma lesions (specificity 94%). False positive antibody accumulation was found in one patient with a post-traumatic subretinal haemorrhage. Immunohistochemistry demonstrated positive MoAb 225.28S binding in all melanoma sections. In summary IS offered substantial sensitivity and specificity in the differentiation of intraocular lesions, particularly choroidal melanomas, naevi, and metastases. In combination with other diagnostic procedures such as ultrasound echography and fluorescein angiography IS proved to be a valuable method in the diagnosis of choroidal melanoma.

Choroid↗
PubMed1992

Granulocytes and three-phase bone scintigraphy for differentiation of diabetic gangrene with and without osteomyelitis.

OBJECTIVE: In diabetic gangrene, concomitant osteopathy and soft-tissue infection often render laboratory and roentgenographic signs unreliable as indicators of osteomyelitis. In this situation, scintigraphic methods can be helpful. RESEARCH DESIGN AND METHODS: Relying on the long-term clinical course as the final indicator of presence or absence of osteomyelitis, we prospectively compared in 31 patients three-phase bone scintigraphy with either indium-labeled autologous granulocytes (n = 20) or 123I-labeled antibodies against granulocytes (n = 11). RESULTS: Three-phase bone scintigraphy and imaging with indium-labeled autologous granulocytes yielded sensitivities and specificities of 95 and 70% for bone scintigraphy and 77 and 100% for granulocyte scintigraphy, respectively. One patient with severe angiopathy and proved osteomyelitis had a negative bone scintigraphy but a positive scintigraphy with labeled antibodies against granulocytes. One patient with aseptic bone necrosis presented with a formally false positive result with both methods. CONCLUSIONS: In contrast to former retrospective studies, three-phase bone scintigraphy compares very well with granulocyte scintigraphy. The care of most patients can be managed with clinical data and this widely available scintigraphic method.

Bone and Bones↗
PubMed1990

Reduced cerebral blood flow in early stages of human immunodeficiency virus infection.

In order to determine if brain perfusion abnormalities, which are known in patients with acquiredimmunodeficiency syndrome dementia, occur in early stages of human immunodeficiency virus infection, technetium 99m hexamethyl-propyleneamine oxime-single-photon emission computed tomography studies were performed in 20 patients infected with human immunodeficiency virus who belonged to Walter Reed stages I through IV. None of these patients demonstrated signs of dementia or severe neurological dysfunction. Pathological patterns of hexamethyl-propyleneamine oxime uptake were seen in 14 patients, seven of whom had normal results during neurological examination. Only four patients had signs of cerebral atrophy on cranial computed tomographic scan. These data suggest that subtle changes in cerebral perfusion seem to arise early in the course of human immunodeficiency virus infection and may indicate human immunodeficiency virus encephalopathy before neurological symptoms or noticeable structural damage occurs.

Acquired Immunodeficiency Syndrome↗
PubMed1990

A simple test to assess cerebrovascular reserve capacity using transcranial Doppler sonography and acetazolamide.

The goal of this study was the development of a simple bedside test to assess cerebrovascular reserve capacity using transcranial Doppler sonography. We studied 33 normal persons at rest and after stimulation of cerebral blood flow with 1 g acetazolamide. Their mean +/- SD increase in blood flow velocity in 54 middle cerebral arteries 10 minutes after stimulation was 24.4 +/- 9.2 cm/sec. We tried to validate the increase in blood flow velocity as cerebrovascular reserve capacity in 21 patients with obstructive carotid artery disease and symptoms of cerebral ischemia. The patients were studied using transcranial Doppler sonography and xenon-133 dynamic single-photon emission computed tomography after acetazolamide stimulation. Their increases in blood flow velocity (delta FV) and increases in cerebral blood flow (delta CBF) correlated significantly in both hemispheres (asymptomatic: Y = 0.32X + 10.65, r = 0.45, p = 0.04; symptomatic: Y = 0.36X + 2.28, r = 0.59, p = 0.004). There was no significant difference between the slopes of the regression lines. Blood flow velocity and cerebral blood flow at rest were not correlated. The increase in blood flow velocity after acetazolamide stimulation offers a simple and reliable method for assessing cerebrovascular reserve capacity.

Acetazolamide↗
PubMed1989

Brain morphology and regional cerebral blood flow in anorexia nervosa.

Cranial computed tomography (CT) was performed in 12 patients with anorexia nervosa, revealing that the majority of the patients displayed ventricular dilatation and/or sulcal widening. In addition, regional cerebral blood flow (rCBF) was measured at admission and once again after weight gain, using xenon-133 dynamic single-photon emission tomography (dSPECT). The mean flow rates assessed at the first examination did not significantly differ from those assessed at the second examination and from those of a control group. There was a significant inverse relationship between the size of the cerebrospinal fluid spaces and the cerebral blood flow in the anorectics; a decrease in ventricular size after weight gain was associated with an increase in cerebral blood flow in this area. This finding, however, has to be interpreted with caution, as partial volume effects render the flow rates ambiguous in brain areas, which, in addition to neuronal tissue, also include ventricular and sulcal structures.

Adolescent↗
PubMed1989

[Brain structure and brain function in anorexia nervosa: a computerized tomography study].

Cranial computed tomography (CT) was performed in 12 patients with anorexia nervosa revealing that the majority of the patients displayed ventricular dilatation and/or sulcal widening. In six patients re-examined these structural brain alterations showed a strong trendency towards normalization after weight gain. With the intention of finding a functional correlate of the CT abnormalities, the regional cerebral blood flow (rCBF) was measured at admission and once again after weight gain and compared with the flow rates of a healthy control group. The mean flow rates assessed at the first examination did not significantly differ from those assessed at the second examination and from those of a control group. Thus, despite the CT findings of structural brain abnormalities, the measurement of the regional cerebral blood flow gave no hint of a reduced functioning of certain brain areas in anorexia nervosa.

Adolescent↗
PubMed1988

Immunoscintigraphy in intraocular malignant melanoma.

Immunoscintigraphy of malignant tumours has become an encouraging tool in nuclear medicine. Early diagnosis of small lesions is mandatory for successful cancer therapy. The scintigraphic detectability of small lesions (less than 1 cm in diameter) by immunoscintigraphy is shown in 39 patients suffering from ocular tumours (37 malignant choroidal melanoma, two benign choroidal naevi) using 99Tcm-labelled F(ab')2 fragments of the anti-melanoma monoclonal antibody 225.28S; this antibody recognizes the high molecular weight melanoma-associated antigen. No adverse effects were observed. In terms of true-positive results, single photon emission computed tomography (SPECT) proved to be superior to planar scans (73% versus 41% true-positive results).

Aged↗
PubMed1988

[133Xe-DSPECT: significance of the cerebrovascular reserve capacity for the diagnosis and therapy of chronic cerebral ischemia].

Using 133Xe-DSPECT, measurements of regional cerebral blood flow (rCBF) were performed before and after stimulation with 1 g of Diamox in 55 patients with symptomatic occlusion of the internal carotid artery (ICA) and 26 patients without evidence of brain disease (normals). In normals, a negative correlation (r = -0.74) of the Diamox-induced increase of hemispheric blood flow (reserve capacity) and rCBF at rest was observed. In 48 of the 55 patients (87%) with ICA-occlusion a reduced reserve capacity was found. The extent of reduction, however, did not correlate with the findings of transmission CT, because 15 of 21 patients (71%) with normal CT-scans presented a moderate to severe reduction of reserve capacity. In contrast, reserve capacity corresponded to the extent of arterial collateralisation as documented by cerebral panangiography. In 31 patients EC/IC-bypass surgery was performed. In follow-up studies reserve capacity increased, especially in patients who had a severe reduction preoperatively. Therefore, the combined measurement of rCBF at rest and of reserve capacity is a sensitive, non-invasive method for the diagnosis of (even bilateral) cerebrovascular disease and can be helpful to identify patients with hemodynamic ischemia, who may benefit from EC/IC-bypass surgery.

Adult↗