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Biomedical subjects

N R Dunnick

Publications and source records attributed to N R Dunnick.

At least 145 records · Page 8Linked to original sources
PubMed1985

Intravenous digital subtraction angiography in the preoperative evaluation of renal masses.

Intravenous digital subtraction angiography (DSA) was performed in 23 patients with renal masses to document tumor extension into the main renal vein or inferior vena cava. The DSA findings were compared with computed tomographic as well as surgical and pathologic findings. Additional data regarding the number of renal arteries present and the relative vascularity of the tumor were also gathered. DSA documented 17 true-negative renal veins, three true-positive renal veins, and one false-negative renal vein. Two patients could not hold their breath long enough to evaluate the renal vein. In 17 of 19 cases, single renal arteries to the affected kidney were correctly identified. In three patients, two renal arteries to the involved kidney were correctly identified. The renal masses were avascular in two patients, hypovascular in five, moderately vascular in eight, and hypervascular in seven. In one case the mass was out of the field of view, and vascularity was not evaluated. In these patients, DSA was an accurate and relatively noninvasive method to assist in the preoperative evaluation of renal masses.

Adenocarcinoma↗
PubMed1985

Nitrous oxide: effective analgesic for vascular and interventional procedures.

During a 2 year period nitrous oxide was used as a sole or supplementary analgesic during 173 vascular or interventional procedures including peripheral angiography and endourologic and endobiliary procedures. The decision to administer nitrous oxide to a given patient was a matter of physician preference. Patients with bowel obstruction, pneumothorax, or chronic obstructive pulmonary disease were excluded from this method of analgesia. The nitrous oxide was administered by a radiology nurse under the supervision of an attending radiologist. Nitrous oxide was used without premedication for 39 procedures and with premedication (usually meperidine 1 mg/kg, promethazine 0.3 mg/kg, or atropine 0.01 mg/kg) in 134 procedures. In 74% of nonpremedicated individuals analgesia was adequate with nitrous oxide alone; 26% required supplemental intravenous medication. In 61% of premedicated individuals pain relief was adequate with nitrous oxide; 39% required supplemental intravenous medication. Complications, including nausea, vomiting, and agitation, occurred in eight patients, but were minor and easily reversed by decreasing the concentration of nitrous oxide. Nasally administered nitrous oxide is a safe, easily used, and effective analgesic.

Analgesics↗
PubMed1985

Percutaneous lithotripsy of staghorn calculi.

Eleven cases of staghorn calculi managed by percutaneous lithotripsy were reviewed. Ten of 11 cases were successful, and 70% of the successfully treated patients were discharged free of any renal stones. The percentage of patients discharged with residual stone fragments was higher than those with either percutaneously managed nondendritic calculi or surgically treated staghorn calculi. The complication rate was higher than for nonbranched stones managed percutaneously and was comparable to that for surgically removed dendritic calculi. Hospital stay averaged 18 days, equal to that for staghorn calculi treated by conventional surgical approach, but considerably longer than for nonbranched stones. Overall results more closely approximated those for surgical removal of staghorn calculi than those for percutaneous removal of nonbranched calculi. However, the principal advantage of percutaneous lithotripsy of staghorn calculi over surgical management is the significant reduction in convalescence after discharge from the hospital.

Adult↗
PubMed1984

Percutaneous transluminal angioplasty in diabetic patients: an effective treatment modality.

Percutaneous transluminal angioplasty (PTA) was performed for nonhealing ulcers, severe claudication, or rest pain in 10 patients with diabetes mellitus. Twenty-two atherosclerotic lesions were dilated in 15 extremities, including 16 iliofemoral arteries and 6 superficial femoral arteries. The procedure was technically successful in all patients and 8 of 9 (89%) with clinical follow-up showed improvement clinically after the procedure. Diabetes is not a contraindication to PTA; rather this modality can be used effectively to control and treat peripheral vascular insufficiency in diabetic patients.

Aged↗
PubMed1984

Modified Johnson basket for antegrade stone extraction.

A modification of a classic Johnson stone basket has been made, such that this basket can pass easily over an angiographic guide wire. With this modification, the Johnson stone basket is an excellent instrument for use in an antegrade or a retrograde fashion for retrieving impacted ureteral calculi. Eleven patients had ureteral calculi manipulated. Of the six ureteral calculi manipulated with standard retractable baskets, only three were successfully extracted from impacted positions. Of the five manipulated with the modified Johnson stone basket, however, four were successfully extracted. The modified Johnson stone basket is an essential instrument in percutaneous manipulation of ureteral calculi.

Humans↗
PubMed1984

CT differentiation of thoracic aortic aneurysms from pulmonary masses adjacent to the mediastinum.

Paramediastinal masses adjacent to the aorta require a diagnostic evaluation to differentiate between tumor and aneurysm. It has been suggested that neoplasm may enhance sufficiently to be confused with a vascular structure or that a clot filled aneurysm may simulate a neoplasm by not filling with contrast medium. Five patients, two with thoracic aneurysms, two with malignancy, and one with a malignancy and an aortic dissection, are presented in whom bolus injection computed tomography (CT) was able to distinguish between aneurysm and mass. The CT examination also accurately visualized the point of communication of the aneurysm with the aorta, defined the relationship of the aneurysm to vital mediastinal structures for planning surgical resection, and helped plan the approach for percutaneous transthoracic needle aspiration when tumor was suspected. Bolus injection CT represents a rational alternative to aortography for mediastinal paraaortic masses.

Adult↗
PubMed1984

Computed tomography of high density renal cysts.

Eleven patients are described whose computed tomography (CT) examinations showed homogeneous, high density (62-76 Hounsfield units) renal masses. In two patients a hemorrhagic benign cyst was found at surgery. In the remaining nine patients the constellation of CT and clinical findings supported the benign nature of this lesion.

Adult↗
PubMed1984

CT demonstration of hyperdense renal carcinoma.

Sharply demarcated homogeneously hyperdense renal lesions have been found to be benign renal cysts, with hemorrhage or a high protein content the most common etiology of the high density. A similar hyperdense renal lesion is presented that was found to be a renal adenocarcinoma. This lesion showed mild contrast enhancement on CT and was found by ultrasound to be a solid mass. The malignant nature of this lesion suggests that further evaluation, such as ultrasound, fine needle aspiration biopsy, or surgery may be needed.

Adenocarcinoma↗
PubMed1984

CT assistance for fluoroscopically guided transthoracic needle aspiration biopsy.

Five cases are presented that illustrate the utility of obtaining limited CT prior to fluoroscopically guided biopsy in patients who have lung or mediastinal lesions that cannot be adequately localized by chest radiography. Each case describes a unique setting in which the CT images facilitate accurate and safe biopsy needle placement. The rare requirement for biopsy using CT alone, which can be considerably more time consuming, is emphasized.

Adult↗
PubMed1984

Computed tomography of benign angiomatous lesions of the extremities.

Thirteen patients with benign angiomatous lesions of the extremities were evaluated by CT. The relationship of the lesion to specific muscle groups and fascial planes was defined better by CT than on plain radiography or angiography. Computed tomography without contrast enhancement demonstrated well circumscribed masses of lower attenuation value than the surrounding muscle. Eight of the 11 patients who received intravenous injection of contrast material showed characteristic punctate or curvilinear structures within the mass, which had attenuation values similar to normal blood vessels. The characteristic CT features of benign angiomatous lesions of the extremities are presented.

Adolescent↗
PubMed1984

Percutaneous dissolution of renal calculi using ultrasonic litholapaxy.

The surgical treatment of renal calculi has been markedly changed by percutaneous manipulation and ultrasonic dissolution. The low morbidity and decreased cost of this procedure make it an obvious choice over classic surgical operations. We report our experience with percutaneous ultrasonic stone dissolution in 23 patients.

Adult↗
PubMed1984

Effect of region assignment on relative renal blood flow estimates using radionuclides.

To determine the value of the initial phase of the Tc-99m DTPA renogram in the direct estimation of relative renal blood flow in dogs, the ratios of the slopes of renal time-activity curves were compared with the ratios of measured blood flow. Radionuclide results were dependent on region-of-interest (ROI) and background ROI assignment, and correlated well with measured relative flow only with a maximum renal outline region. Curve slope ratios correlated well with measured flow ratios with and without background correction, while 1- to 2-minute uptake ratios correlated well only when corrected for background.

Animals↗
PubMed1984

Diagnosis and significance of liver metastases in small cell carcinoma of the lung.

One hundred fifty-seven consecutive patients with small cell lung cancer seen at the National Cancer Institute over a four-year period underwent a series of pretherapy liver staging procedures to determine optimal means of detection and prognostic implications of hepatic metastases. Liver evaluation included physical examination, liver function tests, and liver scan (radionuclide or computerized tomography [CT]), as well as percutaneous and/or peritoneoscopy-directed liver biopsy when possible (74%). Liver metastases were detected in 26% of patients. Peritoneoscopy was the most sensitive method of liver evaluation and increased the detection of liver metastases when done in a sequential fashion after percutaneous liver biopsy from 18 to a total of 27 patients. Of the noninvasive procedures, radionuclide and CT liver scan were the most accurate concurring with liver biopsy in 87% of patients but permitting correct discrimination of stage in excess of 96% of patients. The accuracy of this noninvasive procedure was enhanced by an algorithm combining the results of radionuclide liver scan with liver function tests to detect patients with high or low likelihood of liver involvement. The survival and response of patients with liver metastases was significantly worse than those without such metastases with no three-year disease-free survivors among patients with liver metastases.

Actuarial Analysis↗
PubMed1984

Iopamidol: new, nonionic contrast agent for excretory urography.

Iopamidol, a new, nonionic contrast agent, was evaluated in 18 patients undergoing excretory urography. None of the 18 patients experienced any side effects or adverse reactions. No abnormalities were noted in serum chemistries, complete blood cell counts, urinalyses, or electrocardiograms. The half-life of iopamidol in 17 patients with normal renal function was 2.5 hr. The urograms were judged to be of good or excellent quality in 15 of 16 patients using doses of 200 and 250 mg l/kg of iopamidol. Two patients who were studied using a dose of only 120 mg l/kg had urograms rated poor. Fifteen iopamidol urograms (mean iodine dose, 17.4 g) were compared in a blind fashion with 15 meglumine diatrizoate studies (iodine dose, 29 g). No qualitative difference could be detected between the two groups of urograms. Iopamidol may provide equal-quality diagnostic studies with a lower iodine dose and perhaps greater safety than the currently used ionic agents.

Adult↗
PubMed1984

Mesenteric vein thrombosis: CT identification.

Superior mesenteric vein thrombosis was identified on computed tomographic scans in six patients. In each case, contrast-enhanced scans showed a high-density superior mesenteric vein wall surrounding a central filing defect. Four of the six patients had isolated superior mesenteric vein thrombosis. A fifth patient had associated portal vein and splenic vein thrombosis, and the sixth patient had associated portal vein and inferior vena cava thrombosis. The diagnosis of superior mesenteric vein thrombosis was confirmed by angiography in two patients and by surgery in a third. One of the six patients had acute ischemic bowel disease. The other five patients did not have acute ischemic bowel symptoms associated with their venous occlusion. This study defines the computed tomographic appearance of mesenteric vein thrombosis. A dense venous wall surrounding a central lucency representing blood clot was present in all six cases.

Humans↗
PubMed1984

CT diagnosis of ruptured abdominal aortic aneurysm.

Abdominal computed tomography was performed in six patients with suspected ruptured abdominal aortic aneurysm but in whom an alternate clinical diagnosis was seriously considered. In each patient, a large aortic aneurysm was demonstrated in association with a retroperitoneal accumulation of high-density blood. The retroperitoneal blood was primarily confined to the extracapsular perinephric space. In four of the six patients, a focal area of the aortic wall was indistinct on the side of the retroperitoneal hemorrhage at the presumed site of rupture. Five of the six patients underwent emergency surgery, which confirmed the site of aneurysm, presence of rupture, and the location of fresh retroperitoneal blood.

Aorta, Abdominal↗