Virginia C. Poirier

Angiography in the Diagnosis of Chronic Gastrointestinal Bleeding

Abstract Correlation was positive between angiographic and subsequent pathologic findings in 40 of 53 patients with chronic unexplained gastrointestinal bleeding. It is believed that, in a patient with a history of chronic recurrent bleeding, an anatomic lesion is generally present and can be demonstrated by arteriography even if active bleeding is not in progress at the time of examination. Only 2 of the 53 patients in this study were actively bleeding at the time of examination. The arteriographie details of an intussusception and an ulcerated Meckels diverticulum are also described.

Spinal Sonography and Magnetic Resonance Imaging in Patients with Repaired Myelomeningocele: Comparison of Modalities

The goals of this study were to evaluate the feasibility of using ultrasonography of the spine in the follow‐up evaluation of patients with repaired myelomeningocele at birth and to compare sonography with the accepted modality of magnetic resonance imaging. Over a period of 4 years we performed 165 sonographic studies in 101 patients; 107 sonographic studies had MR imaging results for comparison. We collected our data prospectively. The quality of the sonograms was good in 110 of 129 studies, acceptable in 17 of 129, and poor in two of 129. The sonographic examinations failed in 33 of 165 studies (20%). Concordant information was obtained between ultrasonography and magnetic resonance imaging in the following percentage of studies: level of the distal end of the cord in 82%, position of the cord in the canal in 59%, presence of hydromyelia in 63%, cord duplication in 96%, adhesions in 16%, intradural mass in 37%, cord measurements in 85%, and dural sac measurements in 83%. At the lumbosacral level, we saw no cord pulsation in 57% of the studies in patients with cord adhesions and in 20% of those without adhesions. At the lower thoracic level, we saw no pulsation in 35% of the studies in patients with cord adhesions and in 7% of those without adhesions. Postoperative studies of cord release surgery in eight patients showed varied findings. We conclude that in those patients who have a spinal defect or interlaminar space allowing proper visualization of the lumbosacral spinal canal, ultrasound can provide fairly similar information to that obtained with magnetic resonance imaging of that area with no need for sedation and at a reduced cost. Ultrasonography seems more sensitive than magnetic resonance imaging in the detection of cord adhesions, which is particularly relevant in the diagnosis of tethering.

Phase III clinical trial comparing iodixanol and iohexol in cerebral angiography

RATIONALE AND OBJECTIVES We report on our early clinical experience in the United States with the nonionic dimeric (6:1 ratio) contrast medium iodixanol in cerebral angiography. Iodixanol has an osmolality less than half that of monomeric, nonionic contrast media such as iohexol at equivalent iodine concentrations and is isosmotic to blood. METHODS Forty-nine adult patients undergoing elective cerebral angiography were studied in a phase III, double-blind, randomized, parallel-design clinical trial comparing the safety and diagnostic efficacy of iodixanol at 320 mg I/ml (IOD-320) and iohexol 300 mg I/ml (IOH-300). Diagnostically adequate cerebral angiograms were routinely obtained with both contrast agents. RESULTS A total of 37% of the patients experienced adverse events (48% in the IOD-320 group and 25% in the IOH-300 group). No statistically significant differences were noted between the two groups studied in the proportion of patients with one or more adverse events or in the intensity of the adverse events. The most common adverse event was headache. There were no deaths or serious complications related to either contrast medium in this study. CONCLUSION The results of this phase III trial support the conclusion that iodixanol at a concentration of 320 mg I/ml is comparable to iohexol at 300 mg I/ml in terms of efficacy (overall radiographic diagnostic visualization) and safety.

The effect of intravenous gadolinium on the magnetic resonance appearance of cerebrospinal fluid

The authors determined whether a sufficient amount of intravenously administered gadolinium enters the cerebrospinal fluid (CSF) to visibly shorten the T1 relaxation time. Transfer of intravenously administered contrast media into the CSF has been previously documented for iodinated contrast materials; however, the change in computed tomography density is not sufficient to have a clinically useful myelographic effect. Visible shortening of the T1 of CSF on gadolinium-enhanced magnetic resonance imaging of the spine may have clinical use. Twelve dogs were given gadolinium, and CSF was sampled at intervals over a 6-hour period. The T1 values of the CSF samples were quantitated and plotted against time. The average decrease in T1 was 23% at 60 minutes, which is nearly the peak effect. The increased signal intensity was visible at clinical window settings at 60 minutes. It is possible that this may be clinically useful for certain types of examinations. Importantly, this should be recognized as a normal appearance, and not necessarily a sign of pathology.

Computed tomographic evaluation of C1–C2 in Pediatric cervical spine trauma

The supine open-mouth odontoid view required in most cervical spine trauma series often is difficult to obtain, especially in the pediatric or uncooperative patient. This retrospective study compared thin-section computed tomography with multiplanar reconstructions and the standard plain film cervical spine examination for evaluation of C1–C2 in a group of 31 pediatric patients age 6 years and under with combined craniocervical trauma. The plain film examination demonstrated adequate visualization of C1–C2 in only 58% of patients. The average number of anteroposterior odontoid films was 3.5 per examination (range, 1–6 films). Only 9% of anteroposterior open-mouth odontoid views were felt to be of adequate diagnostic quality vs. 60% of the Fuch’s odontoid view. The computed tomographic examination was diagnostic in 91% of examinations and could be acquired more rapidly.