Biomedical subjects

M Korobkin

Publications and source records attributed to M Korobkin.

216 records · Page 12Linked to original sources

PubMedDate not supplied

The nephrogram of normovolemic, renal artery hypotension.

Experimental hemorrhagic hypotension results in a prolonged nephrogram during excretory urography. We evaluated the effect of reduced renal perfusion pressure on the nephrogram in normovolemic dogs. Renal artery perfusion pressure to one kidney was reduced to 40-50 mm Hg by inflating a renal artery balloon catheter. Subsequent urograms were qualitatively assessed for nephrographic density. Plasma and urinary iodine concentrations were determined by fluorescent excitation analysis. Total renal blood flow (TRBF) and its intrarenal distribution were assessed with isotopically labeled microspheres. In the majority of dogs severe oliguria and a prolonged and increasingly dense nephrogram were produced in the kidney exposed to reduced perfusion pressure. The nephrogram of the contralateral, normotensive kidney rapidly diminished in density, associated with the excretion of a large volume of dilute urine. The total urinary iodine excreted in 60 min was significantly less than that excreted by both kidneys in control experiments. TRBF to the hypotensive kidney was significantly reduced from its control level, and the percentage of TRBF perfusing the outer cortex decreased.

Animals↗

PubMedDate not supplied

Computed tomography of splenic subcapsular hematomas: an experimental study in dogs.

Following baseline CT scans, splenic subcapsular hematomas were produced in dogs by direct splenic trauma. The CT scans of the spleen were obtained one to two hours before and after administration of IV contrast media and one, two, seven, 14 and 28 days following splenic trauma. Variations in the CT image of the hematomas was correlated with time and alterations in the chemical and histologic nature of the hematoma. Initially, the hematomas were isodense with the normal spleen and identified only following IV contrast administration. The initial number of hematomas identified by CT decreased to about half after seven to 14 days and then remained stable. Analysis of the hematomas revealed an initial increase in hemoglobin which was followed by a decrease. Dry weight increased, then decreased; lipid content decreased over time; and calcium content showed no appreciable change. The CT appearance of splenic subcapsular hematomas is dependent on the age of the hematoma. CT scans done soon after trauma should be performed following administration of intravenous contrast media, while less acute hematomas should be apparent without contrast media. Changes in attenuation values of hematomas appear due to a reduction in hemoglobin content and an increase in water content of the hematoma.

Animals↗

PubMedDate not supplied

Computed tomography of experimental acute renal ischemia.

The potential role of computed tomography (CT) in the detection of acute renal ischemia was assessed in nine mongrel dogs. Ischemia was produced by inflation of a balloon catheter in the main renal artery, with scans performed before, during, and after a 60-minute period of ischemia. A small but consistent increase in the attenuation value of ischemic renal parenchyma was observed. When intravenous contrast material was given, the ischemic kidney was markedly less enhanced than the contralateral, nonischemic kidney. By using the contralateral kidney for comparison, the ischemic kidney could be identified with or without the use of a contrast agent. Although calculations of mean pixel values were necessary when a contrast agent was not injected, the abnormal kidney could be easily recognized from the CT images themselves when intravenous contrast material was given. Because of the consistency with which the abnormalities were observed, we recommend a clinical trial of CT in suspected acute renal ischemia.

Animals↗

PubMedDate not supplied

High-resolution multiplanar CT images of the larynx.

The standard technique for computed tomographic evaluation of the larynx utilizes 5-mm contiguous transaxial sections. Multiplanar images reformatted with these sections have not been of clinical use. We have evaluated the practicality of utilizing coronal and sagittal reformatted images produced from contiguous 1.5-mm transaxial sections. The technique of rapid sequential scanning with automatic table incrementation allows 36 contiguous thin section scans to be acquired in less than 9 minutes. Phantom studies showed a marked improvement in spatial resolution with thin section reconstructions. Preliminary clinical evaluation shows visualization of smaller structures with improved edge definition of both low- and high-contrast structures.

Humans↗

PubMedDate not supplied

Computed tomography of the normal patellofemoral joint.

Radiographic assessment of the patellofemoral joint (PFJ) is problematic because conventional views are cumbersome, difficult to standardize, and not reliable for displaying this joint with flexion of the knee less than about 30 degrees. We used computed tomography (CT) to obtain conveniently a direct transaxial view of the PFJ in ten normal human volunteers at different 0 degree, 20 degrees, and 45 degrees of knee flexion and during both contraction and relaxation of the quadriceps muscle. From the CT images we measured femoral trochlear angle, patellar centralization, femoral trochlear depth, and patella tilt angle. In full extension, with the quadriceps muscle relaxed, 19 of 20 knees showed the patella well centered in the femoral trochlear groove. The tilt and centralization of the patella were largely unchanged at 20 and 45 degrees of knee flexion with quadriceps contraction. CT appears to be an optimal method of studying the PFJ. The normal relationships described in this report can be the basis for evaluating patients with known or suspicious history of recurrent subluxation or dislocation of the patella.

Adult↗

PubMedDate not supplied

Computed tomography in the detection of abdominal metastases from malignant melanoma.

Malignant melanoma is an unpredictable and often virulent cutaneous malignancy. Although computed tomography is the most sensitive method for detection of intrathoracic metastases, its value in the assessment of abdominal spread has not been fully defined. We evaluated the sites of CT-identified metastases in 70 patients with pathologically confirmed malignant melanoma. Results were correlated with Clark's level, Breslow thickness, site of the primary, and clinicopathologic stage. CT detected enlarged abdominal or pelvic lymph nodes in 75% of patients with Clark's level 5 lesions but only in 24% and 33% of those with level 3 and 4, respectively. Patients with deep primary lesions of the lower extremities had a high frequency of pelvic node metastases. Liver and splenic metastases were detected in up to 25% of patients with level 4 or 5 melanoma. Adrenal and subcutaneous metastases were frequently discovered as were unsuspected nodules at the lung bases.

Abdominal Neoplasms↗

PubMedDate not supplied

Computed tomographic evaluation of an experimental model for pyogenic liver abscesses.

Computed tomography (CT) was used to evaluate 15 rabbits with experimentally induced liver abscesses. The animals were examined both before and after intravenous contrast injection. After sacrificing the animals, postfreeze CT scans were made to mark the abdomen for 1-cm thick whole body sections for correlating the gross pathology with the results of the CT scans. CT detected 15 abscesses in 13 of the 14 rabbits with true positive lesions. Ten abscesses less than 1.4 cm in diameter were not detected by CT. Contrast agent enhancement was helpful in 70% of the studies. These abscesses have characteristics similar to human liver abscesses, but there was more gas and calcium in the experimentally induced abscesses than is encountered in humans with hepatic abscesses. The model and its CT characteristics appear well suited for future studies in the diagnosis and treatment of liver abscesses.

Animals↗

PubMedDate not supplied

Malignant teratoma of the thyroid in an adult: CT appearance.

A case of malignant teratoma of the thyroid gland is presented. Computed tomography identified an inhomogeneous mass with dense calcifications involving the thyroid gland and compressing the upper airway. Enlarged, peripherally enhancing lymph nodes in the neck and mediastinum suggested its malignant etiology.

Adult↗

PubMedDate not supplied

CT detection of typhlitis.

A case of typhlitis (neutropenic colitis) is reported in which the initial diagnosis was suggested by CT. Radiologists performing CT should be aware of this potentially lethal complication of leukemia, which may appear as a clinically unsuspected finding on CT.

Adult↗

PubMedDate not supplied

Computed tomography of prostatic and bladder rhabdomyosarcomas.

Rhabdomyosarcoma represents the most common soft tissue sarcoma in children. The CT findings in five patients with pelvic rhabdomyosarcoma are reported. In the three male patients the primary tumor originated in the prostate gland whereas in the two female patients the bladder was the primary site. The CT findings in the prostatic tumors included an enlarged, inhomogeneous prostatic mass with invasion of the perirectal fat. In two of these patients there was thickening of the levator ani muscle and one showed tumor invasion through the ischiorectal fossa and sciatic and obturator foramina into the pelvic musculature and bone. In the two patients with bladder tumors, one showed a large mass adjacent to the lateral aspect of the bladder and ascites, suggesting an ovarian primary tumor. The other patient with sarcoma botryoides (a subtype of rhabdomyosarcoma) had a diffusely thickened bladder. Two patients have had a follow-up CT demonstrating tumor regression posttherapy. The characteristically large size of these masses and propensity for local invasion in a young patient are typical features of pelvic rhabdomyosarcoma.

Adult↗

PubMedDate not supplied

Computed tomography of urachal carcinoma.

Urachal carcinoma arises in the clinically silent extraperitoneal space between the bladder apex and the umbilicus. Computed tomography was used to correctly diagnose and stage urachal cancer in two patients. In one case a mass was localized to the bladder wall and immediate juxtavesical region; in the other case an advanced locally invasive lesion was seen to engulf and fisulize loops of small bowel and extend through the umbilicus. Urachal carcinoma has a highly characteristic appearance and location on CT images.

Adenocarcinoma↗

PubMedDate not supplied

Intracaval and intracardiac extension of malignant thymoma: CT diagnosis.

There is disagreement about the ability of CT to detect isolated invasion of mediastinal vessels by malignant thymoma. Diagnosis usually depends on the absence of intact fat planes between the tumor mass and the adjacent vessel. We describe a rare case of CT demonstration of direct intraluminal invasion of a malignant thymoma into the superior vena cava and the right atrium.

Aged↗

PubMedDate not supplied

CT appearance of right gonadal vein.

The CT appearance of the right gonadal vein was studied. It is usually first seen 1 cm below the bifurcation of the inferior vena cava (IVC) and empties into the IVC laterally or anterolaterally 4 cm below the union of the right renal vein and IVC. Occasionally, it empties into an accessory right renal vein rather than the IVC. The right gonadal vein was visualized partially or completely in 80% of patients, and generally measured less than or equal to 4 mm in maximum diameter. It was enlarged in a patient with portal hypertension and in a post-partum woman. Knowledge of its typical CT appearance should prevent confusion with abdominopelvic lymph nodes.

Female↗

PubMedDate not supplied

Lobar primary pulmonary lymphoma: CT findings.

A case of lobar primary pulmonary lymphoma is presented. In an asymptomatic patient with chronic lobar consolidation, CT confirmed the absence of a hilar mass or mediastinal adenopathy and demonstrated patent but stretched and irregularly narrowed bronchi.

Humans↗

PubMedDate not supplied

CT of parapelvic cystic renal cell carcinoma.

Parapelvic renal cysts are benign ubiquitous lesions of the renal sinus frequently demonstrated on CT and ultrasonography. Occasionally a renal parenchymal mass will grow so that its epicenter is within the renal sinus. We report two cases of surgically proven cystic renal cell carcinoma centered in the renal sinus with no apparent connection to the renal parenchyma. Cystic renal cell carcinoma must be excluded whenever a parapelvic cyst with atypical features is encountered on cross-sectional imaging studies.

Adult↗

PubMedDate not supplied

Pelvic CT findings after radical prostatectomy.

OBJECTIVE AND METHODS: To evaluate the spectrum of pelvic CT findings in patients who have had radical prostatectomy, we retrospectively evaluated the pelvic CT of 17 patients after surgery for prostate cancer. All patients were thought to be clinically free of local recurrence of carcinoma. RESULTS: The bladder base was retropubic in 100%, the levator sling was well delineated in its entirety in only 88%, and fat was clearly demonstrated between the rectum and bladder base in only 44%. Unsuspected findings in this group included soft tissue density structures in the resected bed of the seminal vesicles (88%) and a transversely oriented, soft tissue density bar between the bladder base and rectum (53%). A variety of symmetric abnormalities are commonly seen on postprostatectomy pelvic CT. CONCLUSION: Seminal vesical-like soft tissue structures are routinely visualized, and a horizontal bar of soft tissue in the rectovesical space is commonly demonstrated. These structures should not be confused with local tumor recurrence.

Aged↗

PubMedDate not supplied

Segmental autotransplantation of the distal pancreas to the thigh: CT and ultrasound features.

In select patients with pancreatitis, pancreatectomy may be the only alternative for treatment of abdominal pain. Segmental autotransplantation of the distal pancreas to the thigh has been shown to be successful in preventing or reducing the severity of diabetes following pancreatectomy. We present the postoperative anatomy and potential complications identified on cross-sectional imaging.

Chronic Disease↗

PubMedDate not supplied

Percutaneous CT-guided biopsy of adrenal masses: immediate and delayed complications.

OBJECTIVE: To determine the immediate and delayed complications of percutaneous adrenal biopsy and any relationship between biopsy methods and complications. MATERIALS AND METHODS: Medical records and radiological examinations of 83 percutaneous adrenal biopsy were reviewed. Indication for biopsy, inpatient/outpatient status, lesion size and location, imaging modality used, needle type, size, approach and number of passes, biopsy results, immediate complications, and delayed complications were recorded. RESULTS: Computed tomography was used in 79 cases (95%) and ultrasound in 4 (5%). The biopsy approach was posterior in 37 cases, transhepatic in 33, transpancreatic in 9, anterior in 2, transsplenic in 1, and lateral in 1. The total complication rate was 8.4% and was slightly higher for the transhepatic approach (12%) than the posterior approach (8%). Seven complications occurred: two pneumothoraces, two pain, one perinephric hemorrhage, one subcapsular and intrahepatic hematoma, and one hepatic needle-tract metastasis. The posterior approach was complicated by the two pneumothoraces and perinephric blood; the transhepatic was used in the other four. Five of the complications occurred with 22 gauge needles. CONCLUSION: Percutaneous adrenal biopsy is a safe procedure. Complications occurred in 7 of our patients (8.4%).

Adrenal Gland Neoplasms↗