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Biomedical subjects

L M Freeman

Publications and source records attributed to L M Freeman.

At least 73 records · Page 4Linked to original sources

Computed tomography guidance for skeletal biopsy.

Computed tomographic (CT) guided biopsy and abscess drainage of multiple organ systems have been well described. Reports of spinal and skeletal applications have been less common. This study describes the use of CT guidance in the biopsy of various skeletal lesions in 46 patients. Forty-one patients had skinny needle aspirations (18 or 22 gauge) and 23 patients had trephine core biopsies. Sites of the lesions included: thoracic spine-15 patients, lumbosacral spine-17 patients, bony pelvis-6 patients, rib-2 patients, and long bones-6 patients. Fast scanners capable of rapid image reconstruction have overcome many constraints. With CT guidance, the physician who performs the procedure receives virtually no ionizing radiation. The exact location of the needle tip is accurately visualized in relation to the lesion being biopsied and to the vital organs.

Biopsy, Needle↗

Significance of skeletal uptake detected on radionuclide renal perfusion studies.

Since the introduction of Tc-99m labeled radiopharmaceuticals, flow studies have become a useful and readily performed component of renal nuclear medicine examinations. In addition to detecting aberrations of renal perfusion, a number of extrarenal abnormalities may also be surreptitiously detected. Three cases of hyperperfused skeleton, an extremely unusual finding which complements two previous reports in the literature, have recently been observed. All three of the patients, as well as the two previously described, had underlying neoplastic abnormalities. The appearance of perfused skeleton should therefore be recognized as suggesting the presence of underlying neoplastic disease. Considerable interest as to the etiology and magnitude of the increased skeletal perfusion exists. Measurements of normal marrow and osseous perfusion have been reviewed in order to better appreciate the magnitude of increase required for skeletal visualization on renal flow studies. Some considerations as to the etiology of this increase are offered.

Bone Diseases↗

Detection of postcardiotomy bacterial pericarditis with gallium-67 citrate.

A 46-year-old man who had undergone apical cardiac aneurysmectomy with a ventriculotomy graft and implanted automatic cardioverter-defibrillator electrodes, presented with fever, left-sided pleuritic chest pain, and a draining sinus. A Ga-67 scan was performed to aid in determining whether the infection was limited to the chest wall or if it had penetrated deeper to the cardiac structures. Uptake of gallium within the cardiac region, in association with minimal rib uptake of Tc-99m MDP, strongly supported the existence of infection within the pericardium. CT scan demonstrated a pericardial collection which under CT-guided aspiration proved to be purulent. Definitive surgical drainage was performed, and the patient was discharged 4 weeks postoperatively. Ga-67 imaging can provide an accurate and relatively rapid means of localizing infection in the postcardiotomy patient. A thorough bibliography of pericardial gallium uptake is provided.

Cardiac Surgical Procedures↗

The early diagnosis of common bile duct obstruction using cholescintigraphy.

The technetium Tc 99m-labeled iminodiacetic acid cholescintigram is an extremely accurate examination for detecting early obstruction of the common bile duct in acutely ill patients suspected of having acute cholecystitis or possible obstruction days to years after cholecystectomy. The examination accurately detected common bile duct obstruction in 63 of 65 patients in these two diagnostic categories (positive predictive value, 96.9%). Sonographic evaluations in 43 of these patients failed to reveal ductal dilatation or other abnormality in 26 cases (false-negative rate, 63.4%), and was nondiagnostic because of overlying bowel gas in two cases. The success of the radionuclide examination is attributed to its ability to detect functional impedance to bile flow hours to days before anatomic ductal dilatation occurs, and occasionally even before the alkaline phosphatase level and other liver chemistry values suggest the presence of an obstruction.

Bile Duct Neoplasms↗

The use of water ingestion to distinguish the gallbladder and duodenum on cholescintigrams.

Cholescintigraphic diagnosis of acute cholecystitis requires accurate assessment of gallbladder nonvisualization. Confusion may occur when the gallbladder overlies the duodenal sweep or when labeled bile pools in the duodenum. Gallbladder activity could not be differentiated from duodenal activity in 21 patients. The oral ingestion of 225 ml of water permitted successful differentiation of the gallbladder from the duodenum. In 25 control subjects, it was demonstrated that that volume of water did not have a cholecystokinetic effect.

Acute Disease↗

Acute acalculous cholecystitis.

Sixty-eight patients with acute acalculous cholecystitis were reviewed. The results of history and physical examinations were usually nondiagnostic. IDA cholescintigraphy (93 per cent accuracy rate) was the only reliable diagnostic modality. The results of oral cholecystography, intravenous cholangiography and ultrasonography were considerably less reliable. One-half of the patients had gangrenous cholecystitis. Cholecystectomy was the preferred operation with an over-all mortality of 9 per cent. IDA cholescintigraphy is an important new modality for the diagnosis of acute acalculous cholecystitis which, in the past, has often been difficult to diagnose.

Acute Disease↗

Role of Tc-99m IDA scintigraphy in the evaluation of hepatobiliary trauma.

Each year approximately 52 million Americans are injured, of which 11 million require hospitalization and 110,000 die. This has an associated health care cost of 3 billion dollars. Hepatobiliary injuries have always constituted a significant area of involvement. They have become more easily detectable since the advent of technetium-99m analogs of iminodiacetic acid (IDA). Biliary leakage secondary to other causes, such as inflammation, neoplasm, and iatrogenic factors are also well demonstrated in a safe, simple, and rapid manner with radionuclide imaging. The relatively low patient radiation dose that is associated with these procedures permits follow-up studies when necessary.

Acute Disease↗

The radionuclide detection of lower gastrointestinal bleeding sites.

A retrospective review of two years' experience with radionuclide screening to detect lower gastrointestinal bleeding sites was conducted at New York's Montefiore Medical Center. Of 82 studies performed in 63 patients, 13 identified active bleeding sites. Only three of eight angiograms obtained in these 13 patients were positive. Thirteen contrast angiograms were performed in the group of 50 patients with negative radionuclide studies of which ten were negative and one was equivocal. The results of this study suggest that the Tc-99m sulfur colloid study for active lower gastrointestinal (GI) bleeding is an effective screening procedure. Positive studies help determine which vessel to catheterize selectively if an angiogram is to be performed. If vascular ectasis is still suspected following a negative radionuclide study, contrast angiography can be more efficaciously performed on a nonemergent basis.

Adult↗

The role of technetium-99m iminodiacetic acid (IDA) cholescintigraphy in acute acalculous cholecystitis.

Technetium-99m iminodiacetic acid (IDA) cholescintigraphy was performed in 15 patients with acute acalculous cholecystitis. Fourteen of the 15 patients with acute disease had positive findings, indicating the presence of cystic duct or common duct obstruction. One case in which the gallbladder was visualized failed to respond to sincalide stimulation; this was classified as a suggestive finding of disease. The diagnostic accuracy of 99mTc-IDA cholescintigraphy was far superior to the other imaging studies used (8 sonograms, 1 intravenous cholangiogram, 3 oral cholecystograms, 1 percutaneous transhepatic cholangiogram). The 99mTc-IDA study is recommended as the imaging procedure of choice for examining patients with suspected acute acalculous cholecystitis.

Acute Disease↗

Evaluation of the postoperative patient with 99mTc-IDA cholescintigraphy.

In order to assess the role of 99mTc-iminodiacetic acid (IDA) cholescintigraphy in evaluating postoperative patients, a total of 213 studies were performed in 189 patients over a 3-year time period. Of these, 130 studies were obtained in 125 cases with signs and/or symptoms suggesting postcholecystectomy syndrome. A normal sized duct that emptied within an hour ruled out significant pathology with a high degree of accuracy (97%). A less reliable finding of normalcy was the combination of ductal dilatation with functional patency in that three of 20 patients (15%) who exhibited this pattern were proven to have nonobstructing calculi in their common bile duct. AZ spectrum of abnormal findings was encountered. Ductal dilatation was a most significant indicator of partial or intermittent ductal obstruction when it was associated with altered time-activity dynamics in the ducts and secondarily, delayed biliary-to-bowel transit time of the radiotracer. Patterns indicating complete common duct obstruction, cystic duct remnants, and bile leaks also proved to be very sensitive. Seventy-three studies in 56 patients very accurately evaluated the integrity of biliary-enteric bypass anastomosis. Complete and partial obstructive patterns were similar in appearance to those encountered in postcholecystectomy syndrome. Several leaks were also detected in this patient population. Ten studies were performed in eight patients who underwent Billroth II gastroenterostomies primarily to see if afferent loop obstruction was present. Three of these patients did demonstrate dilated A-loops with stasis, thereby making a positive diagnosis possible.

Biliary Tract Diseases↗

Role of cholecystokinetic agents in 99mTc-IDA cholescintigraphy.

Cholecystokinin (CCK) and its C-terminal octapeptide analog, Sincalide, have been utilized in two separate roles for the evaluation of gallbladder disease. These are: (1) prior to cholescintigraphy to evacuate the gallbladder and optimized subsequent filling with radiotracers, and (2) to study contractile function of visualizing gallbladders on cholecystography and cholescintigraphy. As a preparation for 99mTc-IDA studies, it clearly facilitates earlier gallbladder filling in patients with chronic cholecystitis, thereby ruling out complete cystic duct obstruction. The problem lies in the fact that the use of CCK as a premedication markedly decreases the sensitivity of the study to detect chronic cholecystitis, since the findings become indistinguishable from patients with normal gallbladders. For this reason, the authors prefer to obtain delayed images, since chronic cholecystitis is frequently associated with gallbladder filling beyond the first hour. The role of CCK in detecting abnormal gallbladder function in the normally visualizing gallbladder also is controversial. Other studies as well as the author's experience suggests that as much as one-forth of positive cases may be associated with normal gallbladders at surgery and often even on microscopic examination. However, most importantly, the great majority of these patients are relieved of their symptoms following surgery. It appears reasonable that CCK or Sincalide cholecystography or cholescintigraphy may be detecting functional abnormalities before anatomic changes occur and can, therefore, serve as a useful examination in selecting symptomatic patients who may benefit from cholecystectomy.

Acute Disease↗

Prediction of renal functional recovery after relief of upper urinary tract obstruction.

Renal cortical regions of interest were used prospectively to predict recoverability of renal function in 27 patients with unilateral or bilateral urinary tract obstruction. In these 27 patients 36 kidneys with short-term or long-term obstruction were studied. The 131iodine radiohippuran renogram curves were generated from areas of interest from the renal cortex and from the whole kidney. Curves generated during obstruction were evaluated qualitatively to determine if regional cortical renograms exhibited a more normal appearance than total kidney curves. After relief of obstruction renograms generated from the whole kidney were evaluated for evidence of renal functional recovery. Cortical curves obtained before relief obstruction were judged normal, with an abnormal whole kidney renogram in 20 of 36 kidneys. The whole kidney renogram improved after relief of obstruction in all 20 cases. Cortical curves for the remaining 16 kidneys before relief of obstruction had the same abnormal appearance as the whole kidney renogram. After relief of obstruction no evidence of kidney function improvement as measured by the renogram was evident in 14 kidneys. The over-all accuracy of this test of renal functional recoverability was 94 per cent. These data support the hypothesis that when cortical curves appear more normal than total kidney curves there is a strong likelihood of postoperative improvement in renal function when the obstruction is relieved. Abnormal cortical curves are associated with a poor prognosis for renal functional improvement.

Adolescent↗