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Biomedical subjects

W Stanford

Publications and source records attributed to W Stanford.

At least 37 records · Page 2Linked to original sources
PubMed2000

MR imaging of pulmonary and mediastinal malignancies.

The primary goal of performing cross-sectional imaging of the chest in the radiologic evaluation of lung cancer is to obtain information about the character and magnitude of the neoplasm. Patient prognosis and therapy decisions depend directly on identifying the size and full extent of the tumor. The ideal imaging modality therefore should provide reliable information that can be used to assist in accurately staging the malignancy. Traditionally, CT scanning has been used exclusively as part of the preoperative evaluation of primary lung carcinomas. Recent advances in CT scanning technology have greatly improved image acquisition times and image quality and consequently have enhanced the role of CT imaging in the evaluation of bronchogenic carcinomas. Single-breath CT acquisitions of the chest can now be accomplished in a matter of seconds. These rapid acquisitions improve image quality by decreasing respiratory motion, while enhancing patient compliance and throughput. Clearly, CT scanning has matured into an efficient and accurate diagnostic tool to stage primary lung malignancies noninvasively. In its present state of development, MR imaging has one distinct disadvantage that makes it significantly less attractive as a routine lung cancer examination, namely the inability to produce images of the lung that are high in spatial resolution. Also, the sensitivity and specificity of MR imaging, which are similar to those of CT scanning in identifying mediastinal and hilar metastases, offer no clinical advantages. Longer image acquisition times and time constraints force most MR imaging examinations to be abbreviated and limited in coverage. As a result, the necessary exclusion of important anatomic areas routinely visualized by CT scanning may limit the diagnostic power of MR imaging. Finally, MR imaging requires greater physician supervision than CT scanning to direct imaging and to maintain examination quality and thoroughness. Although MR imaging can contribute significantly to the radiologic evaluation of patients with lung cancer, its role is somewhat limited, and it is most useful as a complement to CT scanning. The additional versatility offered by pulse sequences that take advantage of the intrinsic relaxation of tissues greatly facilitates identification of tumor, particularly when local invasion is present. By virtue of the short T1 value of fat, MR imaging may improve the detection of mediastinal disease, particularly in cases in which the sensitivity of CT scanning cannot be optimized because of allergies to contrast or renal insufficiency. MR imaging is superior to CT scanning in demonstrating musculoskeletal anatomy and the neurovascular structures of the neck and mediastinum. Although MR imaging has a potential usefulness in the radiographic evaluation of lung carcinoma, technical shortcomings relegate this modality to a role that is primarily complementary to CT scanning. With time, technological improvements will undoubtedly redefine the role of MR imaging in the radiographic evaluation and staging of bronchogenic carcinomas.

Humans↗
PubMed1999

Multicenter clinical trial of ultrasmall superparamagnetic iron oxide in the evaluation of mediastinal lymph nodes in patients with primary lung carcinoma.

The purpose of this study was to evaluate the clinical efficacy of ultrasmall superparamagnetic iron oxide particles as a magnetic resonance (MR) contrast agent in differentiating metastatic from benign lymph nodes. Eighteen patients with primary lung malignancy and suspected regional lymph node metastases underwent MR imaging before and after Combidex(R) infusion in a multi-institutional study. All MR sequences were interpreted by one or more board-certified radiologists experienced in imaging thoracic malignancy. Each patient was evaluated for the number and location of lymph nodes, homogeneity of nodal signal, and possible change of MR signal post contrast. All patients underwent resection or sampling of the MR-identified lymph node(s) 1-35 day(s) post contrast MR imaging. In all, 27 lymph nodes or nodal groups were available for histopathologic correlation. Combidex had a sensitivity of 92% and a specificity of 80% in identifying pathologically confirmed metastatic mediastinal lymph nodes. Based on our preliminary data, Combidex MR imaging may provide additional functional information useful in the staging of mediastinal lymph nodes.

Aged↗
PubMed1999

PET, CT, and MRI with Combidex for mediastinal staging in non-small cell lung carcinoma.

BACKGROUND: To determine the relative utility of positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging with Combidex (MRI-C) in the non-invasive staging of non-small cell lung cancer (NSCLC) mediastinal lymph nodes (MLN), we compared the three tests' individual performance with surgical mediastinal sampling. In contrast to prior studies, cytology was not used. METHODS: The MLN were evaluated using PET and CT in 64 NSCLC patients. MRI-C was performed in 9 of these patients. MLN with a PET standard uptake value greater than or equal to 2.5, or greater than 1 cm in the short axis by CT or lack of MRI-C signal change were considered positive for metastatic disease. All MLN were sampled and subjected to standard pathologic analysis. PET, CT, and MRI-C scans were interpreted blinded to the histopathological results. Sensitivity, specificity, and accuracy for each scan type to appropriately stage MLN was determined using pathologic results as the standard. RESULTS: Thirty patients had stage I disease, 8 stage II, 9 stage IIIA, 7 stage IIIB, and 10 stage IV. Two-hundred-and-thirty MLN were sampled. Sixteen patients had metastatic mediastinal disease. Compared to the pathological results, PET, CT, and MRI-C had a sensitivity, specificity, and accuracy of 70%, 86%, 84%; 65%, 79%, 76%; 86%, 82%, and 83%, respectively. PET and MRI-C were statistically more accurate than CT (p<0.001). In cases where PET and CT did not identify MLN involvement with NSCLC, 8% (2/25) were pathologically positive. CONCLUSIONS: PET and MRI-C are statistically more accurate than CT. However, the differences are small and may not be clinically relevant. No technique was sensitive or specific enough to change the current recommendation to perform mediastinoscopy for MLN staging in NSCLC.

Adult↗
PubMed1999

Pulmonary oligemia in aortic valve disease.

PURPOSE: To determine whether the severity of the radiographic appearance of oligemia correlates with the severity of cardiac dysfunction. MATERIALS AND METHODS: Nine readers graded a set of 25 chest radiographs (15 cases of aortic valve disease [AVD], 10 control cases without AVD) for blood volume and ventricular size. Blood volume was graded on a scale of -3 (severe hyperemia) to 0 (normovolemia) to +3 (severe oligemia). Ventricular size was graded on a scale of 0 (normal) to 3 (massively enlarged). The oligemia and ventricular size grades were added to yield the radiographic severity index. Pulmonary capillary wedge pressure, pulmonary arterial pressure, stroke volume, and cardiac output were measured at the time of catheterization. RESULTS: The five more experienced readers achieved good nonchance agreement (kappa = 0.48; P < .001). They were unanimous in scoring 12 cases as oligemic; variations occurred only in severity assessments. Oligemia was due to emphysema in one case and to AVD in 11. In oligemic cases, radiographic severity correlated significantly with wedge pressure (r = 0.93, P < .001) and pulmonary arterial pressure (r = 0.93, P < .002). CONCLUSION: Many cases of AVD show oligemia. The severity of oligemia correlates well with hemodynamic abnormality. Oligemia may be caused by atrial-pulmonary-vascular reflex vasoconstriction, low right ventricular output, and possibly high levels of atrial natriuretic factor.

Adult↗
PubMed1999

Why not optimism?

Explore the source record for details and available documents.

Calcinosis↗
PubMed1999

Lung nodules: improved wire for CT-guided localization.

The authors designed three localization wires that increase the utility of percutaneous localization of lung nodules performed in conjunction with video-assisted thorascopic resection. In 17 patients, the custom-made wires dislodged less frequently than did commercially available wires (two of 11 vs three of six, respectively) while allowing the surgeon to apply gentle retraction pressure, which aided the resection.

Equipment Design↗
PubMed1998

Coronary atherosclerosis and its effect on cardiac structure and function: evaluation by electron beam computed tomography.

Coronary artery disease affects millions of Americans annually. In evaluating coronary artery disease, it is important to develop diagnostic methodology that can screen patients before the onset of symptoms or cardiac events and, in addition, evaluate the functional aspects of coronary artery disease, including any residual effects on the heart after events have occurred. Electron beam computed tomography allows the identification of coronary calcium, which is a marker for coronary atherosclerotic disease, and also allows the quantification of cardiac function, which may be altered from coronary atherosclerosis or the occurrence of a cardiac event. Thus, electron beam computed tomographic imaging is having a major impact on the diagnosis and follow-up on coronary artery disease.

Calcinosis↗
PubMed1997

Sacroiliac motion for extreme hip positions. A fresh cadaver study.

STUDY DESIGN: This study placed fresh cadavers in different hip positions and obtained sacroiliac kinematics. The magnitudes and directions of angular and linear sacroiliac motion are reported. OBJECTIVES: To determine the three-dimensional motion at the left and right sacroiliac joints and to explore the mechanical structure of the sacroiliac joint. SUMMARY OF BACKGROUND DATA: Previous in vivo and in vitro studies have reported various amounts of motion at the sacroiliac joints, ranging from no motion to 18 degrees. The results of previous studies have typically not been reported as data in classic engineering terms, and three-dimensional analyses are sparse. Importantly, previous studies have not used external hip positions to elucidate the full range of sacroiliac motion. METHODS: Radiopaque markers were placed in the sacrum and each innominate bone before standardized performance of computed tomography scans at 3-mm intervals, with the fresh cadaver stabilized in the side-lying position on a specially constructed pallet. Computed tomography images were stored on magnetic tape, from which coordinates for centroids of the markers were obtained and subsequent mechanical analyses performed. The intersubchondral lines on the images were traced and reconstructed using computer technology to obtain the thickness of the intersubchondral joint space and the general configuration of the sacroiliac joints. RESULTS: The methods used in this study were validated. The largest amount of sacroiliac motion occurred in the sagittal plane (7 degrees on left and 8 degrees on the right, with a range of 3 degrees to 17 degrees). Definite trends in the direction of angular sacroiliac motion occurred with respect to both bilateral and reciprocal hip joint positions. The translation or linear motion of the posterior superior iliac spines with respect to the sacrum ranged from 4 to 8 mm. This motion tended to occur in all directions, with no detectable trends. The average intersubchondral thickness of the sacroiliac joint was 1.2 mm and the shape of the joint resembled that of an airplane propeller. CONCLUSIONS: Even though the subjects in this study were elderly, considerable angular and linear motion was in evidence. As such, it appears that extreme hip positions are necessary to elucidate full range of motion at the sacroiliac joint. The magnitude and direction of demonstrated sacroiliac motion appears to be sufficient to complement hip joint motion and influence motion at the lumbosacral junction and, thus, low back pain in both the direct and indirect sense.

Aged↗
PubMed1997

Intercostal artery aneurysm associated with coarctation of the aorta: specific finding on MR imaging.

Aneurysm formation has been described in association with aortic coarctation in approximately 10% of patients. The incidence increases with age and reaches 42% in patients over 40 years of age. To our knowledge, only six radiologic reports have described aortic coarctation in association with an intercostal artery aneurysm and none of these reports has described an intercostal artery entering the aneurysm. We present a case in which MR imaging helped identify this unusual abnormality.

Adult↗