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Biomedical subjects

I C Yoder

Publications and source records attributed to I C Yoder.

At least 19 recordsLinked to original sources
PubMed1995

Imaging the effects of diabetes on the genitourinary system.

Diabetes mellitus is a common multisystemic disease with serious effects on the genitourinary system. In the radiology literature, little attention has been paid to developing an integral approach to imaging of the genitourinary tract in diabetes. The long-term effects of diabetes on the genitourinary system include diabetic nephropathy, papillary necrosis, renal artery stenosis, diabetic cystopathy, and vas deferens calcification. Diabetes-associated urinary tract infections include renal and perirenal abscesses, gas-forming infections such as emphysematous pyelonephritis and emphysematous cystitis, fungal infections, and xanthogranulomatous pyelonephritis. Diabetes-associated genital infections include Fournier gangrene and postmenopausal tubo-ovarian abscess. In a diabetic with fever of unknown origin or in the event of a persistent infection in a diabetic with clinical deterioration despite use of antibiotics, radiologic studies can demonstrate the presence of genitourinary complications. Finally, radiologists should be aware of the risk of contrast material-induced nephropathy in diabetics.

Abscess↗
PubMed1994

Percutaneous internal ureteral stent placement: review of technical issues and solutions in 50 consecutive cases.

Fifty consecutive percutaneous ureteral stent placements in 40 patients over 2 1/2 years were reviewed. Thirty-seven of 50 cases were performed following failed retrograde stenting. Antegrade stenting failed in 2/37 (5%) cases of malignant obstruction, and 4/13 (31%) cases of benign ureteral disease. Causes of failure and common technical problems included poor angulation of the percutaneous track, tortuous dilated ureters, tight obstructions, wedging of stent assembly components due to high resistance, and difficulty in positioning of the proximal pigtail. Helpful technical modifications included mid-pole rather than lower pole calyceal access, urinary decompression prior to stenting, and the routine use of a peel-away sheath (success rate 23/24 placements with sheath vs 21/26 without sheath). Stent patency rates were 95% at 3 months and 54% at 6 months. With attention to technique and appropriate modifications, success rate of percutaneous stenting remained high in this series despite the large number of cases referred after retrograde stenting had failed.

Adolescent↗
PubMed1994

Diagnostic imaging in the evaluation of renal lymphoma.

Renal lymphoma usually is a manifestation of disseminated disease and often is asymptomatic. Occasionally, the kidney(s) may be the major or only demonstrable site of disease, which may then present with a variety of urologic symptoms. The imaging studies should be tailored according to the presenting symptoms and prior history. Currently CT with intravenous contrast material enhancement is the study of choice for both the evaluation of renal involvement as well as staging of the disease. When necessary, CT or sonography may be used to guide percutaneous needle biopsy of suspicious masses. The role of the various imaging techniques, including MR and positron emission tomography, in the evaluation of renal lymphoma is discussed.

Angiography↗
PubMed1993

Fluoroscopically guided percutaneous suprapubic cystostomy for long-term bladder drainage: an alternative to surgical cystostomy.

Percutaneous large-bore suprapubic cystostomy catheters were placed under fluoroscopic guidance in 60 patients as an alternative to surgical cystostomy. Foley catheters (16-20 F) were placed in 57 of the patients in a one-stage procedure. Ten-French catheters were initially placed in three patients because of difficulty in dilating percutaneous tracks because of obesity (one patient) or dense scar tissue (two patients). Three weeks later, 18-F Foley catheters were placed in these three patients when mature tracks had developed, making dilation easier. Minor complications occurred in three patients, including superficial track bleeding in two and urosepsis in one. Fifteen patients were lost to follow-up. Suprapubic catheters provided excellent long-term drainage (range, 0.5-36 months; mean, 16 months; median, 18 months) in the remaining 45 patients. The authors conclude that percutaneous suprapubic catheter placement is a safe and effective procedure that provides excellent long-term bladder drainage.

Adult↗
PubMed1992

Imaging the urethra in men and women.

This review describes and illustrates the radiologic techniques, normal anatomy, and common congenital and acquired lesions of the urethra in men and women. Voiding cystourethrography and retrograde urethrography are the most common imaging modalities employed in the diagnosis of anatomic lesions of the urethra. The appearance of the urethra may then dictate the need for further functional evaluation with urodynamic studies. Congenital lesions in men include posterior and anterior urethral valves and duplicated urethra. In women, ectopic insertion of the ureter into the urethra is the usual congenital lesion. Acquired urethral lesions include benign prostatic hypertrophy in men and strictures and diverticula in both men and women.

Adult↗
PubMed1992

Primary retroperitoneal neoplasms: how close can we come in making the correct diagnosis.

The primary retroperitoneal tumors form a rare and diverse group of neoplasms, the origin of which is independent of the various retroperitoneal organs and unrelated to systemic diseases, such as lymphomas, lymphadenopathy, or metastases. Radiologic investigation, mainly cross-sectional imaging and, to a lesser extent, angiography is essential in the diagnosis and management of these tumors. The radiologist often is challenged to identify the origin and specific tissue composition of the imaged neoplasms. When the radiologic findings are combined with patient information and clinical data, the correct diagnosis may be made in many cases. Imaging-guided percutaneous needle biopsy further enhances the diagnostic yield of the various imaging modalities by establishing the diagnosis without the need for exploration.

Adolescent↗
PubMed1991

Nonspecific magnetic resonance appearance of renal oncocytomas: report of 3 cases and review of the literature.

We report the magnetic resonance appearance of 3 cases of solitary renal oncocytomas. All lesions were of low to moderate signal intensity on T1-weighted images and became considerably brighter on the more heavily T2-weighted images. One lesion contained a large central area of cystic degeneration, while the other 2 were solid. A central stellate scar was present in the smaller of the 2 solid lesions. Our observations lend further support to earlier reports on the nonspecific magnetic resonance features of oncocytomas.

Adenoma↗
PubMed1991

Hysterosalpingography in the 1990s.

All physicians involved in the evaluation and treatment of infertility rely heavily on the information provided by hysterosalpingography. For many years this study has provided images of the lumina of the fallopian tubes that are not available by other diagnostic means, and it also gives the most accurate outline of the uterine cavity. Hysterosalpingography will therefore continue to be a valuable study in the upcoming decade, and it is important now to take account of the many advances in technology that impinge on the execution and interpretation of this study. In this article we first update the continuing debate about elements of the study itself, involving techniques and the choice of contrast material. We also consider surgical advances, such as the widespread use of microsurgical reconstruction of the fallopian tube, that increase the demand for hysterosalpingography. Since radiologists are asked to evaluate the results of surgery, it is essential for them to be familiar with the postoperative appearances of the fallopian tube. Finally, we consider what must be by far the most important development of the 1990s, the continuing integration of hysterosalpingography with new interventional and imaging techniques. Fallopian tube catheterization expands the examination of the fallopian tube and offers new therapeutic applications. Transvaginal sonography and MR imaging have allowed noninvasive exploration of the female pelvis. Correlation of hysterosalpingography and MR imaging is particularly useful in the diagnosis of uterine myomas and congenital uterine duplication anomalies when surgery to preserve or enhance the reproductive capacity of the uterus is indicated. Sonography and MR imaging should be correlated with hysterosalpingography to provide a more efficient diagnostic and therapeutic approach to the common mechanical causes of infertility.

Catheterization↗
PubMed1990

Spermatic cord sarcomas: sonographic and CT features.

Five patients with sarcomas of the spermatic cord were imaged with sonography and/or computed tomography (CT). The former modality is most helpful in demonstrating the extratesticular origin of the mass and evaluating its scrotal extension for local staging. CT is necessary for pelvic staging and searching for distant metastasis. The fat in liposarcomas was easily identified by CT, although it was not echogenic on sonography. Sonography should be the primary imaging modality for scrotal or inguinal masses. If a neoplasm is found, CT should be used for staging, prior to definitive surgical treatment.

Aged↗
PubMed1989

Migratory lobar nephronia.

Lobar nephronia or focal bacterial nephritis is a pre-abscess stage of localized cellulitis and has been shown to represent a focal imaging manifestation of what is frequently a diffuse renal process. To the best of our knowledge, although multi-focal bacterial nephritis has been described, a migratory pattern has not been observed. This report describes a previously healthy 32-year-old woman with pathologically proven lobar nephronia that exhibited a migratory pattern on serial computed tomography (CT) and a prolonged course on antibiotic therapy. Possible etiologies for this unusual course, along with the CT, sonographic and needle biopsy features of this disease are discussed.

Adult↗
PubMed1989

Adrenal cysts: imaging and percutaneous aspiration.

Six patients with primary adrenal cysts were encountered during a period of 3 years. Multiple imaging modalities were used to characterize these lesions, including magnetic resonance imaging in one case. Percutaneous aspiration was performed on four of the six cysts - in one case, in the operating room prior to excision of the cyst. Cholesterol was detected in four cysts and cortisol in one cyst. Cytologic findings from aspiration biopsy were benign in all five cases. Two cysts were removed, one of them after reaccumulation of the fluid after needle aspiration. The findings in this small series of adrenal cysts suggest that in certain cases, complete cyst aspiration, rather than surgical excision, may be carried out initially for diagnosis and management of indeterminate suprarenal cystic lesions and symptomatic cysts of the adrenal gland.

Adrenal Gland Diseases↗
PubMed1988

Urinary extracorporeal shock wave lithotripsy: equipment, techniques, and overview.

Second generation urinary lithotriptors are characterized by extensive technical alterations and significant equipment improvement in the functional, logistical, and medical aspects of shock wave lithotripsy (SWL). These newer devices feature a water bath-free environment, a reduced anesthesia requirement, improved imaging, functional uses in addition to lithotripsy, or combinations thereof. Shock wave generation by spark gap, electromagnetic, piezoelectric and microexplosive techniques are related to their peak energy, frequency, and total energy capabilities which impacts on both anesthesia needs and the length and number of treatment sessions required to pulverize calculi. A master table summarizes the types of SW energy, coupling, imaging systems, patient transport, functional features, cost, and treatment effectiveness of 12 worldwide lithotriptors in various stages of investigative and clinical trials as monitored by the Food and Drug Administration (FDA) of America.

Equipment Design↗
PubMed1986

Percutaneous ultrasonic lithotripsy of symptomatic renal calculi in children.

Percutaneous ultrasonic lithotripsy of upper urinary tract lithiasis is a well-established procedure in adults. We successfully applied this technique to completely remove symptomatic renal calculi in two children with idiopathic hypercalciuria. The procedure was well tolerated and no complications occurred. Both patients were discharged within 4 days of the lithotripsy. This method is an alternative to surgery for the removal of large or impacted calculi from the upper urinary tracts of pediatric patients.

Adolescent↗
PubMed1986

Sonography in transitional cell carcinoma of the renal pelvis.

Real-time ultrasound examination of the kidneys was performed in 11 patients with transitional cell carcinoma of the renal collecting system. Each sonogram revealed a zone in the renal sinus which was less echogenic than the normal sinus and which corresponded to the extent of the tumor. Although the specificity and sensitivity of this finding are not yet known, this appearance should suggest the diagnosis of transitional cell carcinoma.

Aged↗
PubMed1986

Magnetic resonance imaging of the kidney.

After a few years of the use of clinically oriented imaging, magnetic resonance (MR) can now be measured against the other cross-sectional radiologic imaging techniques. Its superior sensitivity in demonstrating diseases of the central nervous system and heart has yet to be matched by similar success in the detection of abdominal disease. However, MR is evolving further and improvements in hardware, software, and pulse sequence selection are expected to continue. We present here the experience accumulated to date in the MR evaluation of the kidney in its normal and diseased states.

Adult↗