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G R Applegate

Publications and source records attributed to G R Applegate.

7 recordsLinked to original sources
PubMed1992

Variability in the enhancement of the normal central skull base in children.

We studied the signal and enhancement characteristics of the central skull base prospectively in 40 children aged 13 days to 8 years, on a 1.5 T MRI system. Identical standard short TR/TE spin echo sequences in the sagittal plane were performed before and after intravenous gadolinium-DTPA. The sequences used for comparison were filmed at identical window and level settings. Three independent observers assessed (1) the intensity of contrast enhancement of the basisphenoid, basiocciput and presphenoid, (2) the signal intensity of the spheno-occipital synchondrosis, (3) the degree of pneumatization of the sphenoid sinus and (4) the uniformity of signal intensity reflecting fatty replacement of the marrow of the basisphenoid, basiocciput and presphenoid. In 16% and 28% respectively of cases there was no enhancement of the basisphenoid and basiocciput after gadolinium administration; in 42% and 44% there was mild enhancement, and moderate or intense enhancement was observed in 42% and 28% of cases. Even when there was irregular fatty replacement, residual hemopoietic clements could enhance intensely. When skull base neoplasms are being investigated, the normal signal irregularity and enhancement of the central skull base in children must not be confused with pathologic invasion of the marrow.

Child↗
PubMed1992

MR angiography of the head and neck: value of two-dimensional phase-contrast projection technique.

MR angiography is commonly performed by using two- and three-dimensional time-of-flight and three-dimensional phase-contrast techniques. These procedures require long examination times and processing of imaging data by computing maximum intensity projections. Two-dimensional phase-contrast projection angiography has neither of these disadvantages. We analyzed the value of this technique for head and neck MR angiography in 84 patients and 15 control subjects. Patients were examined to resolve specific clinical questions such as the presence of arteriovenous malformations (20 cases), patency of carotid and vertebral arteries (35 cases), patency of the superior sagittal sinus (14 cases), patency of saphenous vein bypass grafts (11 cases), and vascularity of masses (four cases). Conventional angiograms were available for correlation in 22 patients. Two-dimensional phase-contrast projection angiograms were generated by using a gradient-recalled-echo sequence sensitized to flow with the use of flow-encoding gradients. Projection MR angiograms were obtained in approximately 3.5 min by combining images obtained with flow-encoding gradients applied along the axes defining the image plane. MR angiograms were subjectively evaluated by three observers without reference to routine MR images or conventional angiograms. High-quality studies were obtained in 93% of control subjects and 90% of patients examined. The findings based on phase-contrast angiography were confirmed with conventional angiography in 21 of 22 patients for whom conventional angiograms were available. Evaluation of vascular grafts and of the patency of major cranial vessels was easily done with two-dimensional phase-contrast angiography and was useful in postoperative follow-up examinations. We also advocate its use for superior sagittal sinus thrombosis and follow-up examinations in patients with arteriovenous malformations.

Arteriovenous Malformations↗
PubMed1991

Pyomyositis: early detection utilizing multiple imaging modalities.

Pyomyositis represents 3% to 4% of surgical admissions in East Africa, however, there were no reported cases in the United States prior to 1971. Since, there have been numerous reports of this entity. Four recent cases are presented utilizing multiple imaging modalities including magnetic resonance. MR was very sensitive to early soft tissue inflammatory processes and demonstrated these focal abscesses with superior anatomic localization. MR is advocated in the initial evaluation of a focal process. In a systemic, nonfocal process, nuclear medicine WBC or Gallium Scans to localize areas for further MR scanning is recommended.

Abdominal Muscles↗
PubMed1989

Radionuclide detection of duodenal ulcer perforation.

An elderly obese male with a lengthy history of melanotic stools was admitted and was shown to have a posterior duodenal ulcer by endoscopy. He became obtunded and developed infected ascites. Because of his obesity, ascites, and inability to cooperate, the GI radiologist felt that a Gastrografin upper GI series would not be helpful. We therefore gave the patient 99mTc-labeled sulfur colloid and tap water through his nasogastric tube. We were able to clearly image a site of perforation at the duodenal bulb communicating with the lesser sac.

Aged↗
PubMedDate not supplied

Dynamic CT in superior mesenteric artery syndrome.

In superior mesenteric artery (SMA) syndrome the third portion of the duodenum is entrapped by the aorta and the SMA. We used dynamic CT to study five patients with SMA syndrome due to cachexia, cast syndrome, scleroderma, trauma, and periaortic adenopathy. This method provides diagnostic insight into the etiology and possible therapeutic options in the care of these patients.

Adult↗