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Biomedical subjects

R K Zeman

Publications and source records attributed to R K Zeman.

At least 91 records · Page 5Linked to original sources
PubMed1988

Of cholescintigraphy, sonography, and great bears. A view on modern biliary imaging.

We review the discrepancies and the reasons for them, in two articles in this issue of the Journal to conclude that clinical findings hold the key to selection of the proper imaging test in biliary obstruction. Cholescintigraphy is a more rewarding approach in detecting low grade obstruction, as by common duct stones, whereas in the patient with prolonged painless jaundice, and the high likelihood of a malignancy, computed tomography or ultrasound will yield the best results. Because of the potential for noninvasive imaging to miss choledocholithiasis and because of ever increasing therapeutic options, direct cholangiography will continue to be the mainstay in definition evaluation of the biliary tract.

Cholestasis↗
PubMed1987

Gallbladder perforation. An imaging analysis.

We evaluated the radiologic studies of 23 patients with surgically or autopsy-documented gallbladder perforation. Extravasation was shown by cholescintigraphy and cholangiography in seven patients and corresponded to free perforation or large pericholecystic loculation. In 16 patients, ultrasonography and computed tomography detected fluid and abscesses outside the gallbladder ranging from 1 to 2 mm pericholecystic fluid collections to large phlegmonous masses. A right, upper-quadrant mass on plain films and scattered calcification in this area suggested perforation. Gallbladder perforation could be diagnosed or suspected preoperatively in ten patients and antemortem in 22 of 23 individuals. This rate of recognition, higher than previously reported, may be ascribed in part to improvements in biliary imaging.

Adult↗
PubMed1987

Focal periportal sparing in hepatic fatty infiltration: a cause of hepatic pseudomass on US.

An unusual pattern of hepatic fatty infiltration was detected sonographically in 31 patients over a 1.5-year period. At appropriate gain settings and time gain compensation, the liver parenchyma demonstrated diffuse increased echogenicity except for a solitary hypoechoic area with relatively distinct margins, usually located in the medial segment of the left hepatic lobe. This hypoechoic periportal focus varied in size between 1.5 and 5 cm and was typically ovoid, but was occasionally spherical or irregular in shape. Eight patients with such foci underwent percutaneous needle biopsy because of concern that there was a space-occupying mass. Microscopic examination of specimens from the hypoechoic periportal region revealed normal hepatic parenchymal cells, while tissue samples from the surrounding liver had high fat levels. In the remaining 23 patients, correlative radiologic studies supported the diagnosis of fatty liver and excluded a central-mass lesion. A localized area of normal hepatic tissue should be considered among the possible diagnoses when a circumscribed hypoechoic periportal area is demonstrated within a fatty liver.

Adult↗
PubMed1987

Renal metastases: clinicopathologic and radiologic correlation.

The clinical and radiologic features of 27 patients with renal metastases arising from eight different types of nonlymphomatous primary malignancies are presented. Renal metastases were generally detected late in the course of the malignancy. In 23 patients there were no symptoms referable to the kidney. Urinalysis was normal in nine patients and showed microscopic hematuria in nine, gross hematuria in four, and proteinuria in four. Radiologically, metastases were usually multifocal; however, metastases arising from colon, lung, and breast carcinoma were sometimes large, solitary, and otherwise indistinguishable from primary renal cell carcinoma. Three of four melanoma metastases and three of seven lung metastases infiltrated the perinephric space. Computed tomography was the most sensitive modality, depicting renal metastases in all 24 cases in which it was employed, followed by ultrasound and intravenous urography. In patients with a history of malignancy, renal metastases outnumbered renal cell carcinomas by approximately 4:1. This study indicates that a new renal lesion in a patient with advanced, noncurable cancer is more likely metastatic than primary and that biopsy in this setting is unlikely to be of aid.

Adult↗
PubMed1987

Esophageal malignancy: imaging results and complications of combined endoscopic-radiologic palliation.

Fifty-one patients with advanced cancer of the esophagus underwent 191 endoscopic palliative procedures, including bouginage, laser therapy, bipolar electrocoagulation, and stent placement. In three patients free perforations developed; these were treated immediately and no sequelae developed. Perforations confined within the tumor mass were diagnosed with CT in two patients and did not require treatment. Methods of endoscopic palliation are discussed with reference to the radiologic studies and techniques. The radiologist must evaluate tumor topography and esophageal wall thickness with computed tomography and esophagography to aid in the choice of palliative therapy. Knowledge of each technique and its risks by the radiologist is essential for useful consultation with the endoscopist before, during, and after the procedure.

Adenocarcinoma↗
PubMed1987

Thymic atrophy and regrowth in response to chemotherapy: CT evaluation.

Twenty-nine consecutive patients 2-35 years old underwent serial thoracic CT evaluations for metastatic disease. Thymic volumes were determined for each patient during cycles of chemotherapy and were compared with the patient's clinical status. This group included patients with Hodgkin's disease (13 patients), osteogenic sarcoma (five), testicular neoplasm (four), Wilms' tumor (three), rhabdomyosarcoma (two), malignant fibrous histiocytoma (one), and Ewing's sarcoma (one). Seven patients with mediastinal lymphoma had tumor involvement of the thymus and therefore were excluded. The 22 remaining patients showed cyclic thymic volume changes in response to chemotherapy or its discontinuance. During the first course of chemotherapy the thymic volume decreased by an average of 43% in 20 of 22 patients. Between the first and second course, regrowth was observed in all 20 of these patients. Among the six patients who received a second course of therapy, an average volume decrease of 36% was observed during the second course with regrowth again occurring during recovery from chemotherapy. Thymic rebound (regrowth 50% greater than baseline volume) occurred in five patients, three of whom were in clinical remission. The thymus appears to atrophy during the administration of chemotherapy and regrow during the recovery phase of chemotherapy in 90% of the patients studied. Thymic hyperplasia or rebound is a relatively common phenomenon occurring in 25% of patients. The size of the thymus appears to be extremely sensitive to chemotherapy.

Adolescent↗
PubMed1986

Aortic dissection following coronary artery bypass surgery: diagnosis by CT.

We describe an unusual case of aortic dissection causing spinal cord infarction. The dissection arose from an intimal tear at the suture line of a coronary artery bypass graft. CT was used to diagnose the dissection and to demonstrate its extension to the aortoiliac bifurcation and innominate artery and its rupture into the left pleural cavity. The most common causes of intimal tears following cardiac bypass surgery are aortic cross-clamping, aortic cannulation, and injury during suturing of the graft to the aorta. An underlying disease of the aorta such as atherosclerosis, cystic medial necrosis, or aortitis is commonly present. CT is an accurate and safe means of detecting aortic dissections following cardiac surgery, and is also useful in assessing the extent of the dissection and identifying its rupture into the pleural or pericardial cavity.

Aortic Dissection↗
PubMed1986

Prevesical hematoma: a complication of prostatic biopsy.

Pelvic hematomas following prostatic biopsy are rare. We describe 2 cases of hematomas occurring in the prevesical space (space of Retzius) following transrectal biopsy. Computed tomography (CT) was useful in defining the extent of the hematoma and showing density changes related to the age and suppuration of the hematoma. While cystography has been used to diagnose prevesical hematomas, CT better assesses the size of the hematoma and changes that may occur over time.

Biopsy↗
PubMed1986

Invasion of the inferior vena cava by testicular seminoma: demonstration by computed tomography and venography.

Involvement of the inferior vena cava (IVC) by testicular neoplasms is unusual and often clinically unsuspected. We present a patient with testicular seminoma that involved the IVC secondarily and caused multiple pulmonary emboli requiring the placement of a caval filter. The radiographic features of this phenomenon are presented with special emphasis on the computed tomographic (CT) appearance of caval thrombosis and pulmonary embolus. The characteristically low density lymphadenopathy of seminoma may obscure the diagnosis of caval thrombosis on CT. Although the findings are nonspecific, tumor invasion of the IVC should be suspected in all patients with testicular neoplasms who demonstrate caval thrombosis radiographically.

Adult↗
PubMed1986

Renal mass imaging: the internist's role.

The busy internist will encounter numerous renal masses when ordering nonurologic imaging. Concise and quick delineation of cystic from solid masses is necessary. Cystic masses constitute the majority of these masses and once their nature is diagnosed, they require no further work-up or referral. Often, a single imaging technique is unable to confidently establish the cystic nature of a renal mass. Proper selection of an additional imaging modality will often be successful in establishing the cystic characteristics of a benign mass. Referral to a urologist is not necessary in this setting, since the internist can coordinate the imaging evaluation with proper radiologic consultation. Alternatively, when a mass is determined to be solid, urologic consultation and surgical evaluation are necessary. Minimization of the imaging sequence and hospitalization are critical in the diagnostic-related group era. Aimless wandering in the quagmire of imaging techniques is very expensive and nonproductive. Proper selection of one or two imaging tools and occasionally needle puncture should produce clarification of the cystic or solid nature of renal mass. On the basis of our experience, we have designed an imaging algorithm that provides a simple and concise approach to the diagnosis of a renal mass. It differs in design from that previously suggested by us and others because of decreased emphasis on nuclear medicine and greater emphasis on computed tomography. The more pivotal position assumed by computed tomography is based on improved scanner design and several large series attesting to the accuracy and cost-effectiveness of this imaging technique. It behooves internists to appreciate the role of various imaging tools in evaluating a renal mass. With radiologic consultation, internists should strive to confidently establish the cystic nature of a renal mass and to refer to a urologist solid masses or those whose nature remains persistently equivocal.

Angiography↗
PubMed1986

Gastric tuberculosis: a manifestation of acquired immunodeficiency syndrome.

A Haitian man with acquired immunodeficiency syndrome (AIDS), fever, malaise, and diarrhea is described. A computed tomographic (CT) scan showed a retrogastric mass with an associated ulcer. An upper gastrointestinal tract study showed an ulcer with both benign and malignant features. Endoscopy revealed a malignant-appearing ulcer, but cultures and histologic examinations of surgical biopsy specimens indicated gastric tuberculosis. The relationship between tuberculosis and AIDS is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Obstruction of the upper-pole moiety in renal duplication in adults: CT evaluation.

Delineation of the presence and anatomy of an obstructed, nonfunctioning upper-pole duplex system often requires multiple imaging techniques. Computed tomography (CT) was used to evaluate duplex systems in five adult patients. Independent of renal function, CT allowed assessment of the presence of a duplex system, determination of whether the system was obstructed, assessment of the quantity of residual parenchyma in the upper-pole system, determination of whether the ectopic ureter was intravesical or extravesical, and assessment of the retroperitoneum to look for unusual causes of upper-pole ureteral obstruction.

Adult↗
PubMed1986

Computed tomography appearance of a right cervical aortic arch.

The clinical diagnosis of cervical aortic arch rests on the detection of a pulsatile mass in the supraclavicular fossa. Unfortunately, clinical differentiation of a cervical arch from an aneurysm of the great vessels can be difficult. Dynamic computed tomography (CT) can aid in this differentiation and avert the need for angiography.

Adult↗
PubMed1985

Acute focal bacterial nephritis: a systematic approach to diagnosis and treatment.

Acute focal bacterial nephritis, synonymous with acute lobar nephronia or focal nonliquefactive pyelonephritis, represents a localized area of renal inflammation. Clinically, acute focal bacterial nephritis presents as acute pyelonephritis but is distinguishable by the presence of a focal mass on excretory urography. The further distinction between acute focal bacterial nephritis and other renal masses is aided by the appropriate use of renal sonography and computerized tomography. The clinical and imaging manifestations in 9 patients with acute focal bacterial nephritis are described. Our experience coupled with a review of the literature suggests that a systematic approach to the diagnosis and management of acute focal bacterial nephritis allows for the most efficacious use of the noninvasive imaging modalities.

Acute Disease↗
PubMed1985

Enhanced pancreatic CT imaging utilizing a geometric magnification technique.

Computed tomography (CT) using a geometric magnification technique was found to improve spatial resolution in phantom studies when compared with conventional third-generation geometry images. The clinical feasibility of using geometric magnification, small focal spot size, and dynamic contrast enhancement was studied in 143 patients referred to CT for clinically suspected pancreatic disease. This population included 46 patients with a normal pancreas and 36 patients subsequently proven to have primary pancreatic carcinoma. Using this new technique in conjunction with dynamic contrast enhancement resulted in high quality pancreatic images. Despite the limitations in tube current associated with a small focal spot size and low total heat capacity of the system, clinical imaging was not adversely affected. Use of the geometric magnification technique is recommended in departments where it is technically feasible.

Adult↗
PubMed1985

The value of hepatobiliary scanning in complex liver trauma.

To evaluate the use of biliary scintigraphy with 99m Tc-dimethyl analogs (HIDA) in traumatic liver injuries, a group of 26 patients with penetrating and blunt liver injuries were studied. The results indicate that HIDA scanning is an effective noninvasive method of evaluating the hepatobiliary tree in the post-traumatic setting. The HIDA scan is a sensitive tool for studying the hepatic parenchyma and the presence or absence of bile leaks. Its evaluation of the extrahepatic biliary ductal system is not specific and should be assessed with further studies. Gallbladder nonvisualization by HIDA scans in this setting cannot be presumed to be secondary to acute cholecystitis and should be interpreted with extreme caution.

Adult↗