PubMed Health⌕ Search

Biomedical subjects

D Front

Publications and source records attributed to D Front.

At least 91 records · Page 5Linked to original sources
PubMed1985

Nuclear magnetic resonance imaging of liver hemangiomas.

Nine patients with cavernous hemangioma of the liver were examined by nuclear magnetic resonance imaging (MRI) with a 0.5 T superconductive magnet. Spin-echo technique was used with varying time to echo (TE) and repetition times (TR). Results were compared with 99mTc red blood cell (RBC) scintigraphy, computed tomography (CT), echography, and arteriography. Four illustrated cases are reported. It was possible to establish a pattern for MRI characteristics of cavernous hemangiomas; rounded or smooth lobulated shape, marked increase in T1 and T2 values as compared with normal liver values. It is concluded that, although more experience is necessary to compare the specificity with that of ultrasound and CT, MRI proved to be very sensitive for the diagnosis of liver hemangioma, especially in the case of small ones which may be missed by 99mTc-labeled RBC scintigraphy.

Adolescent↗
PubMed1985

Uptake of gallium-67 citrate and [2-3H]deoxyglucose in the tumor model, following chemotherapy and radiotherapy.

Uptake of 67Ga and [3H]DG after radiation and chemical therapy was measured in a tumor model. Uptake of both agents in treated viable tumors did not differ significantly from the uptake in viable control tumors. However, when tumors showed, after therapy, partial or complete fibrosis, there was a significant decrease in uptake. Viable tumors showed the whole range of weight response to therapy, and the mean weight of viable tumors did not differ significantly from the mean weight of partially viable tumors. The results indicate that, in the tumor model used in this study, 67Ga and [3H]DG could be used to monitor tumor response to therapy. Tumor weight was not a reliable indicator of the effect of therapy at early stages when the tumor is partially viable.

Animals↗
PubMed1984

Technetium-99m-labeled red blood cell imaging.

Red blood cells labeled with 99mTc constitute a suitable intravascular agent for imaging of vascular abnormalities. Hemangiomas are characterized by low perfusion and a high blood pool. This "perfusion blood-pool mismatch," not encountered in other lesions, may help in the specific diagnosis of this tumor. This is particularly so in cavernous hemangiomas of the liver where three-phase 99mTc-labeled red blood cell scintigraphy should precede liver biopsy. Red cell scintigraphy also is useful for establishing the vascular nature of hemangiomas of the head and neck and the skin and for diagnosis of venous occlusion. Heat-damaged red blood cells provide a specific spleen imaging agent. This should be used when patients with suspected splenic pathology have equivocal colloid scintigraphy.

Adult↗
PubMed1984

Scintigraphic assessment of atrial function in patients with longstanding hypertension.

Right and left atrial function were assessed using Fourier analysis of gated radionuclide images in 14 normal subjects and 50 patients with long-standing essential hypertension. Slopes representing filling and early diastolic emptying were similar for both atria; however, early diastolic emptying of the left atrium was slowed markedly in the hypertensive group (42.6 +/- 18.6 counts/sec., vs. 79 +/- 16 in normal persons; p less than 0.001), implying a reduction in left ventricular compliance. The right ventricular ejection fraction was depressed in hypertensive patients compared with normal subjects (37.1 +/- 6% vs. 43.4 +/- 8.1%; p less than 0.01). These findings may be helpful in understanding the effect of hypertension on the left and right heart and could have prognostic and therapeutic implications as well.

Adult↗
PubMed1984

The blood-tissue barrier of human brain tumors: correlation of scintigraphic and ultrastructural findings: concise communication.

Through the first 2 hr, uptake of [Tc-99m]pertechnetate and of Co-57 bleomycin were assessed in 29 brain tumors and were correlated with the ultrastructure of the tumor's capillary endothelium. No difference in uptake was found between the two tracers. Permeability of brain tumors to these agents was found to be governed by the same ultrastructural features that determine permeability in experimental brain tumors: the type of junction between contiguous endothelial cells in the capillaries. Meningiomas, which showed very high uptake of the radiotracers, demonstrated open or punctate junctions with short fusion of apposed membranes. They also showed a large number of pinocytotic vesicles and fenestrae. Capillaries of tumors without uptake had a small number of short tight junctions (less than 0.25 mu) between adjacent endothelial cells and a relatively large number of long junctions (greater than 0.5 mu). In intracerebral tumors that showed relatively high uptake, the reverse was true: most of the junctions were short and only a few long junctions were found. That uptake of [Tc-99m]pertechnetate and of Co-57 bleomycin depends on tumor capillary ultrastructure (which determines the permeability) suggests the possibility of the use of radiopharmaceuticals as in vivo indicators of tumor permeability. Brain scintigraphy may help to asses brain-tumor availability to non-lipid-soluble chemotherapeutic drugs.

Bleomycin↗
PubMed1983

Single-photon emission computed tomography. A method of measuring cerebral blood flow in three dimensions (preliminary results of studies in patients with epilepsy and stroke).

The recent development of single-photon emitting radiopharmaceuticals that reflect cerebral blood flow has introduced a new era for the useful application of nuclear medicine to the investigation of neurological disease. Using 123I labelled N-isopropyl-p-iodoamphetamine, we have performed emission-computed tomographic scans of the brain in several clinical settings. These studies display cross-sectional maps of cerebral blood flow and promise significant clinical utility in a variety of brain diseases. In the eight patients with epilepsy, the scans showed good localization of the abnormal foci, and correlated well with the findings at operation in the five patients who were submitted to surgery. All 10 patients with stroke had abnormal scans, and the abnormalities in cerebral blood flow were frequently more extensive than the lesions seen on the transmission-computed tomographic scan. This initial experience leads us to anticipate an increasing role in clinical neurology for single-photon emission computed tomographic scans of cerebral blood flow.

Adolescent↗
PubMed1983

An all-digital nuclear medicine department.

An all-digital nuclear medicine department is described. Nuclear medicine images are acquired by a separate computer interfaced to each camera. The digital images are viewed, manipulated, and interpreted from remote display stations in an interpretation area. The interpretation is dictated into a Rapid Telephone Access System (RTAS), where the voice is digitized and stored. By dialing the patient's identification number, the referring physician can hear the interpretation over any telephone. The images are filed on large storage discs. The digital scans can be rapidly and easily accessed for later review by the use of several directory programs. This system has brought not only efficiency and cost savings, but the ability for remote viewing elsewhere in the hospital and telephone transmission of nuclear cardiology studies from community hospitals for interpretation in the digital nuclear medicine department.

Computers↗
PubMed1982

Brain abscess and its surgical management.

A series of 56 patients with brain abscesses who were treated over a period of 23 years is reviewed. Patients with posttraumatic infections were not included. The operative mortality was 11%. Aspiration of purulent material, radical excision of the abscess, drainage of pus, or a combination of these procedures was used according to the patient's condition and the location of the abscess. The relatively low mortality may be related to the preoperative condition of these patients, who were operated upon in the subacute or chronic stage of their disease. Conservative surgery, especially when functionally important parts of the brain are involved, helps to keep the postoperative neurological deficit as low as possible. Computerized tomography is of primary importance in localizing, diagnosing, and following the evolution of a brain abscess.

Brain Abscess↗
PubMed1982

Initial experience with SPECT (single-photon computerized tomography) of the brain using N-isopropyl I-123 p-iodoamphetamine: concise communication.

Forty-six patients were studied with N-isopropyl I-123 p-iodoamphetamine (IMP) and the Harvard Scanning Multidetector Brain System. In nine control patients, good differentiation between the gray and white matter of the cerebral cortex and the basal ganglia was evident. Regional uptake was affected by physiologic maneuvers (visual stimulation). In 24 patients studied for stroke, IMP images demonstrated areas that were involved in acute infarction in eight patients whose initial transmission computerized tomography (TCT) was normal; IMP also showed perfusion abnormalities larger than the TCT abnormality in ten patients. Perfusion abnormalities were present in 23/24 of these patients. Seven patients studied with a history of TIA had normal TCT and IMP images. In three patients studied during seizure activity, regions of hyperperfusion corresponded to the EEG seizure focus. Markedly decreased activity was present in three patients with brain tumor and corresponded to the focal abnormality on the TCT study. Our study demonstrates the feasibility of assessing regional brain perfusion using a radiopharmaceutical that is lipid soluble and has a high extraction fraction in the brain, together with single-photon ECT.

Amphetamines↗
PubMed1982

An evaluation of 99mTc-labeled red blood cell scintigraphy for the detection and localization of gastrointestinal bleeding sites.

99mTechnetium-labeled red blood cell scintigraphy was performed upon 39 patients with clinical evidence for acute lower gastrointestinal bleeding from an unknown source. Seventeen of 39 patients (44%) had a scan became positive 6 or more h after injection, consistent with intermittent bleeding, in 8 of 17 patients (47%). In the 11 patients in whom the bleeding site was definitely identified by arteriography, surgery, or colonoscopy, scintigraphy correctly localized the bleeding site in 10 of 11 patients (91%). Four of 11 patients (36%) had an active bleeding site identified by arteriography. Ten of 17 patients (58%) with a positive scan required either gelfoam embolization (4 patients) or surgery (6 patients) to control the bleeding, whereas only 1 of 22 patients (5%) required surgery when the scan was negative. Six deaths occurred in the scan-positive patients compared with no deaths in the scan-negative patients. None of the 8 patients who had arteriography and no active bleeding site by scintigraphy had arteriographically demonstrable active bleeding. Scintigraphy provides a reliable noninvasive test to screen patients in whom arteriography is being considered to localize active bleeding sites. If the arteriogram is negative, the scintigraphic findings alone may guide the surgical or arteriographic intervention. In addition, scintigraphy identifies two patient populations which have considerably different morbidity and mortality.

Adult↗