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Biomedical subjects

W Hoddick

Publications and source records attributed to W Hoddick.

9 recordsLinked to original sources

CT body stereotaxic system for placement of needle arrays.

A new CT body stereotaxic system that is particularly suited to multiple placements of needles precisely in parallel is described. By scanning through a right triangle placed on the patient's skin, the stereotaxic method defines an entry point for the first needle placement. An articulating arm is then used to aim the needle at the entry point and hold the needle at the correct angle. The arm can be angled so that the complex approaches from one scan plane to another can be made to place needle arrays through inaccessible lesions, for instance, beneath the diaphragm. Animal and phantom studies have shown that placement of multiple needle arrays in parallel from CT scan data is possible.

Biopsy, Needle↗

Renal allograft rejection: US evaluation.

Real-time ultrasonography (US) was performed on the allografts of 100 consecutive renal transplant recipients at the time of allograft biopsy. Evaluation of the sonograms included the grading of parameters previously demonstrated to be indicative of allograft rejection. The appearance of the renal sinus fat, allograft size, corticomedullary ratio, sharpness of the corticomedullary junction, medullary conspicuity, presence of focal parenchymal abnormalities, and thickening of the pelvic or infundibular wall were individually evaluated. The authors correlated the US and the histopathologic findings. While the accuracy of a positive prediction of rejection was relatively high (83%-90%), this result is influenced by the relatively high prevalence of rejection in the biopsy group (83%). Accuracy of a negative prediction was uniformly low (17%-30%). Mild rejection was difficult to differentiate ultrasonographically from no rejection, although severe rejection could usually be differentiated from mild or no rejection, particularly in patients with the interstitial type of rejection.

Graft Rejection↗

CT body stereotaxis: an aid for CT-guided biopsies.

A new body stereotaxic system used to facilitate CT-guided biopsies is described. By scanning through a triangle placed on the patient's skin, the method defines an entry point for the biopsy. An articulating arm is then used to aim the needle at the entry point and hold the needle at the correct angle. The arm can be angled so that complex approaches from one scan plane to another can be made in order to take biopsies of lesions beneath the diaphragm. Using the system, 23 of 25 lesions were hit on the first needle manipulation; two manipulations were needed for each of the other two lesions. In comparison with previous experience, procedure time was decreased and the numbers of needle manipulations and localization scans were decreased 75% and 90%, respectively.

Biopsy, Needle↗

Sensitivity of sonography in pyonephrosis: a reevaluation.

OFF sonographic features distinguishing randomly selected cases of simple hydronephrosis (34 patients) from pyonephrosis (16 patients) were reviewed in 50 patients. Fluid-fluid levels and coarse medium-intensity echoes within the renal collecting system were highly reliable findings for pyonephrosis in 10 patients. However, in six patients with proven pyonephrosis, the renal collecting system either was anechoic (four patients) or contained low-level echoes (two) that were difficult to distinguish from artifacts. Although the specificity for diagnosing pyonephrosis was 100%, the sensitivity was only 62%. Because of the consequences of misdiagnosis, sonographically guided diagnostic needle aspiration may still be required in patients with urosepsis and significant hydronephrosis.

Adult↗

Sonographic monitoring of hepatic cryosurgery in an experimental animal model.

Several cryosurgical techniques for freezing hepatic parenchyma have been developed. To assess the efficacy of sonographic monitoring of hepatic cryosurgery, an experimental animal model was devised. Real-time sonography was used to monitor the in vivo evolution of hypothermically induced hepatic cryolesions in four mongrel dogs. The results suggest that sonography is an effective and accurate means of monitoring the entire freezing and thawing cycle in hepatic cryosurgery.

Animals↗

Sonography of the fetal duplex kidney.

The sonographic features of the fetal duplex kidney are reviewed in five cases. Four cases had proven obstruction of either an upper (3 cases) or lower pole (1 case) moiety. Identification of two separate collecting systems may be difficult in utero. Therefore, the key to the sonographic diagnosis is recognition of asymmetric hydronephrosis between the dilated and nondilated moieties.

Female↗

Magnetic resonance imaging of aortic disease: preliminary results.

Fourteen patients with a variety of aortic diseases were evaluated with magnetic resonance imaging (MRI). These included abdominal aortic aneurysms (eight cases), aortoiliac aneurysm (one), thoracoabdominal aneurysm (one), aortic dissections (four), and Takayasu arteritis (one). The size and extent of aneurysms, the presence of thrombus or atherosclerotic debris, the relation to renal and iliac arteries, and the effect of aneurysms on adjacent structures were readily demonstrated by MRI. The size of the residual lumen in a variety of vascular diseases and abnormal blood flow patterns could be assessed. In aortic dissection, MRI permitted identification of intimal flaps and determination of the origin of aortic branches from either of two lumina. Thickening of the wall and luminal narrowing of the aorta and arch vessels in Takayasu arteritis were clearly defined. These early results indicated that MRI achieved precise and complete assessment of a number of aortic abnormalities without the administration of any type of contrast material. Thus, early experience suggests that an important application of MRI will be as a totally noninvasive and reliable method for evaluating aortic disease.

Adult↗

CT and sonography of severe renal and perirenal infections.

Twelve patients with urosepsis and severe renal or perirenal infections were evaluated with both computed tomography (CT) and sonography. Six patients had nine proven renal or perirenal abscesses larger than 2 cm in diameter. One patient had multiple microabscesses smaller than 1 cm. Five patients had CT or sonographic evidence of focal or multifocal bacterial nephritis. Computed tomography correctly diagnosed all renal (six) and perirenal (three) abscesses. Sonography was falsely negative in a patient with multiple microabscesses and in another patient with a gas-forming perinephric abscess. In one patient with four bilateral renal abscesses, sonography correctly diagnosed only one of the abscesses. In the five patients with focal or multifocal bacterial nephritis, CT demonstrated poorly defined, poorly enhancing lesions in all cases. Sonography was normal in three of these patients. Although this report is based on a limited experience, computed tomography seems to be the more sensitive method of evaluating severe renal and perirenal infections.

Abscess↗