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Biomedical subjects

J F Simeone

Publications and source records attributed to J F Simeone.

At least 37 records · Page 2Linked to original sources
PubMed1989

Imaging of pancreatic neoplasms: comparison of MR and CT.

Thirty-two patients with pathologically proved pancreatic carcinomas or cystadenomas were evaluated with MR images obtained with T1-weighted spin echo (short TR/short TE), inversion recovery, and T2-weighted spin-echo (long TR/long TE) pulse sequences. CT was used as the reference standard to determine the ability of MR to delineate normal and abnormal pancreatic anatomy and thereby to exclude or detect pancreatic malignancy. Short TR/short TE spin-echo sequences were significantly better (p less than .05) than inversion recovery or T2-weighted spin-echo sequences in resolution of both normal and abnormal anatomy. Resolution of pancreatic anatomy correlated (r = .9) with the image signal-to-noise ratio. In seven (22%) of 32 cases, MR visualized pancreatic tumors better than CT did because it showed a signal intensity difference between the tumor and normal pancreatic tissue. Overall, the slight superiority of MR over CT for tumor visualization tended to occur in larger tumors and was not statistically significant. On T1-weighted images, 63% (20 of 32) of pancreatic tumors studied had lower signal intensities than normal pancreatic tissue, whereas on T2-weighted sequences (TE = 60, 120, and 180 msec) only 41% (13 of 32) of tumors had increased signal intensities. Currently available MR imaging techniques offer no significant advantages over CT for evaluating the pancreas for neoplasia.

Adult↗
PubMed1989

Routine sonographic techniques fail to quantify gallstone size and number: a retrospective study of 111 surgically proved cases.

We analyzed sonographic images retrospectively to determine their value in quantifying gallstone size and number in 111 surgically proved stone-containing gallbladders for which routine preoperative sonograms were available. The number and size of of stones found on pathologic examination were correlated with the results of image analysis. In patients with more than one stone, observable size differences were recorded if the smallest stone diameter was less than 50% of the largest stone diameter. Estimates of gallstone size and number from preoperative sonograms were correct in only 23 (21%) of 111 cases. Stone size and number were overestimated as often as they were underestimated. Stones of a uniform size were recognized correctly in 59 (92%) of 64 cases. Stones of two different sizes were correctly identified in only 14 (30%) of 47 cases; the second, smaller stones were missed in 26 (79%) of 33 cases. These findings indicate poor sonographic characterization of gallbladder contents when imaging studies are performed solely to determine the presence or absence of gallstones.

Cholelithiasis↗
PubMed1988

Complicated pancreatic abscesses: problems in interventional management.

Twenty-five patients with grade D or E pancreatitis underwent percutaneous drainage. These patients required multiple computed tomography (CT) examinations, multiple catheter insertions, multiple catheter manipulations, and long-term catheter drainage. Eight of the 25 patients were successfully treated with catheter drainage alone. Sixteen underwent surgical drainage, ten after attempts at percutaneous drainage and six prior to radiologic drainage. Of the ten patients who had initial percutaneous drainage, only four were clinically improved from the drainage procedure alone. Although the fluid component of the abscess was often adequately drained in all ten patients, surgery was required to remove pieces of necrotic debris. Six patients who underwent surgical debridement had residual abscesses in the post-operative period and were all successfully treated with percutaneous drainage. One patient died from unrelated causes. Successful interventional management of patients with pancreatic abscesses requires intensive radiologic intervention and monitoring and may be better served by a combination of radiologic and surgical means.

Abscess↗
PubMed1988

Image-guided pleural biopsies: indications, technique, and results in 23 patients.

Twenty-six pleural biopsies were performed on 23 patients over a 3-year period. Twenty-three biopsies were performed guided with ultrasound; one, with computed tomography; and two, with fluoroscopy. Indications for an image-guided pleural biopsy were (a) pleural masses or thickening that were either not seen on chest radiographs or seen only on one view and (b) small or loculated pleural effusions of unknown cause with no mass seen. If only pleural fluid was present, reverse bevel needles were used for biopsy (n = 15). If a discrete pleural mass or thickening was seen with cross-sectional imaging, standard (16-20 gauge) biopsy needles were used (n = 11). In the 23 patients, biopsy results were true positive in ten (nine with malignancy, one with tuberculous pleurisy), true negative in ten (confirmed either at subsequent thoracotomy or clinical follow-up), and false negative in three. Complications were few, with a significant pneumothorax occurring in two patients (8.7%). Image-guided biopsy of small pleural lesions and small pleural effusions can be performed by the radiologist who understands the special needles and techniques involved.

Biopsy, Needle↗
PubMed1988

Thoracic empyema: management with image-guided catheter drainage.

Forty-three patients with thoracic empyema were treated by means of image-guided catheter drainage. In 40 patients, image-guided catheter drainage was the primary treatment method; in three it was used after conventional, surgical chest tube placement failed. Drainage was performed with ultrasound guidance in 30 patients (69.8%), computed tomography in eight (18.6%), and fluoroscopy in five (11.6%). A combination of guidance modalities was used in six patients. Image-guided catheter drainage alone was successful in 31 of 43 patients (72.1%). In three patients (7%), empyemas were initially drained, but a thoracotomy was ultimately required because of a persistent pleural peel. In eight patients (18.6%), the procedure failed, predominantly due to tube clogging, persistent pneumothorax, or progressive development of a pleural peel. In one patient, drainage was successful but he died 10 days later of complications of renal failure. No major complications were encountered. Treatment of these patients requires a thorough understanding of the pathogenesis of pleural space infection, principles of empyema drainage, techniques of abscess drainage under image guidance, and the use of a pleural drainage system.

Adult↗
PubMed1988

Severe acute pancreatitis after percutaneous biopsy of the pancreas.

A retrospective review of 184 pancreatic biopsies in 178 patients was performed to assess the prevalence of severe postbiopsy pancreatitis. The size, contour, and pathology of the lesions biopsied; the course of the needle (i.e., through bowel or other viscera); the size of the needle; the number of needle passes made; and the guidance technique used were analyzed. Severe pancreatitis developed in five cases (five patients) 5/184 or 3% of the biopsies), usually within 24-48 hr. Three of the five patients who developed pancreatitis had true-negative biopsies (normal pancreas) proved either at surgery (two) or at clinical follow-up (one). The diagnoses for the two remaining patients were adenocarcinomas. In four of the five patients, the diagnosis of severe pancreatitis was made by inspection at surgery. The fifth case was diagnosed by CT. Three patients who underwent surgery and one patient who had percutaneous drainage recovered from the pancreatitis. The fifth patient died despite surgical intervention. All five patients with pancreatitis had masses 3 cm or smaller as compared with the overall group, in which 71 (39%) of the 184 biopsies performed had masses smaller than 3 cm. Overall, 18% of the biopsies were true negative, compared with the 60% true-negative rate in the pancreatitis group. The bowel was transgressed in 21% of all 178 patients, including three of the five pancreatitis patients. We conclude that although the risk of pancreatitis is exceedingly small in percutaneous needle biopsies, it may occur, and at a higher rate than previously reported.

Acute Disease↗
PubMed1988

Physical characteristics of gallstones removed at cholecystectomy: implications for extracorporeal shock-wave lithotripsy.

The criteria by which patients are selected for new, nonsurgical forms of gallstone therapy will influence the use of these techniques. We estimated the number of patients with gallbladder stones who are potentially suitable for extracorporeal shock-wave lithotripsy according to the current Food and Drug Administration protocol for the United States trials of the Dornier gallbladder lithotriptor. Exclusion criteria include patients with (1) more than three stones, (2) stones less than 0.5 cm or more than 3.0 cm in diameter, (3) radiopaque stones, and (4) a nonfunctioning gallbladder. The gallbladder contents in 100 consecutive patients undergoing cholecystectomy were analyzed according to the number, size, and calcium content of the stones as determined by specimen radiographs. Because none of these patients underwent preoperative oral cholecystography, an estimated percentage of functioning gallbladders was taken from the literature. Preoperative symptoms were not considered in determining a patient's eligibility for gallbladder lithotripsy. On the basis of these criteria, we estimated that 85% of our surgical patients would have been excluded from extracorporeal shock-wave lithotripsy according to the current Food and Drug Administration protocol for the Dornier gallbladder lithotriptor.

Calcium↗
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

Sonography in the follow-up of 100 patients with thyroid carcinoma.

High-frequency, high-resolution sonography was used to detect recurrent thyroid carcinoma in 73 patients with papillary carcinoma, 16 with medullary carcinoma, 10 with follicular carcinoma, and one with small-cell carcinoma. Of the 36 patients with negative sonograms, 35 had no other evidence of recurrence, while one had surgical proof of recurrence. Of 25 patients with positive sonograms, confirmed with surgery or radioactive iodine (I131) scanning (sonographic sensitivity 96%, specificity 83%), palpation was negative in 17 (palpation sensitivity 32%, specificity 100%). Thirty-two patient with positive sonographic findings had no objective clinical proof of recurrence. There were seven false-positive studies. This study suggests that sonography may be the method of choice for earliest detection and localization of recurrent carcinoma of the thyroid.

Adenocarcinoma↗
PubMed1987

Sonographic guidance in diagnostic and therapeutic interventions in the pleural space.

One hundred eighty-seven diagnostic and therapeutic interventional procedures in the pleural space were performed by using sonographic guidance. These consisted of diagnostic aspiration (118), drainage of malignant and nonmalignant effusions (41), empyema drainage (17), pleural sclerotherapy with tetracycline or bleomycin (7), and pleural biopsy (4). Diagnostic aspiration was performed with 20-gauge needles, and therapeutic and empyema drainages were performed by trocar technique with either a 7-French Sacks catheter or a specially designed empyema drainage catheter. Pneumothoraces were seen in 3% of the patients, and most of these were treated by the radiologist with placement of a Heimlich valve. We conclude that the use of sonography allows rapid localization of pleural fluid collections and instant monitoring of drainage of noninfected fluid collections and empyemas.

Biopsy↗
PubMed1987

Transcystic biopsy: a new approach to posterior pelvic lesions.

Six patients with masses located posterior to the bladder were biopsied using an anterior transcystic approach. Conventional biopsy needles were introduced through the bladder with both sonographic (five) and CT guidance (one). Clinically important diagnoses of recurrent carcinoma (four) or cytology-negative fluid (two) were made in all patients. One patient had a transient episode of minimal hematuria immediately after the biopsy. Otherwise, there were no complications. Transcystic biopsy appears to be a safe and effective technique for biopsy or aspiration of posterior pelvic masses.

Biopsy, Needle↗
PubMed1987

Chronic cholecystitis. An analysis of diagnostic strategies.

To define the optimal diagnostic approach for suspected chronic cholecystitis comprehensive management strategies were developed. Using a computer model, the frequency of appropriate surgery, inappropriate surgery, complications, death, and medical costs were compared in populations of patients with various disease prevalences. The optimal strategy began with ultrasonography, followed by an oral cholecystogram when the ultrasonogram was inconclusive. Oral cholecystogram also was employed when additional diagnostic studies failed to provide another explanation for the patient's symptoms. Compared with strategies using only ultrasonography or oral cholecystography, the combination strategy lowered the frequency of inappropriate surgery from 7.1 to 4.4% and direct medical costs from $1,877 to $1,766 per patient in a population with a 20% prevalence of chronic cholecystitis. The differences persisted at higher prevalences of cholecystitis and when sensitivities and specificities of the tests were varied over ranges reported in the literature. Diagnostic accuracy and direct medical costs could be improved by a more frequent interpretation of subtle abnormal ultrasonographic findings as inconclusive and by a more liberal use of oral cholecystography. This analysis demonstrates that a strategy combining ultrasonography and oral cholecystography is superior to the use of either test alone and is cost-efficient.

Cholecystitis↗
PubMed1986

Sonographic monitoring of LHRH analogue therapy in idiopathic precocious puberty in young girls.

Precocious puberty in young girls is defined as the development of secondary sexual characteristics and gonadal growth before 8 years of age. Approximately 60% of isosexual precocious development in girls has no organic cause and is termed idiopathic precocious puberty. Thirteen young girls with idiopathic precocious puberty were treated with LHRH analogue under a well-established protocol. Pelvic ultrasound was added to the protocol to examine ultrasound's role in supplying a morphologic parameter of suppression of the pubertal process. Initially, 11 patients had ovarian volumes greater than normal, and ovarian cysts measuring 0.5 cm to 4 cm in diameter were identified in seven patients. All 13 patients had enlarged pretreatment uteri greater than 3 cm in length. Eleven of these patients had a pubertal or adult uterine configuration. After 1 year of therapy, 11 patients had normal prepubertal ovarian volumes, and 12 of 13 patients had a decrease in ovarian volume. No demonstrable cysts were present at 1 year. Eleven had a reduction in uterine length. Nine of the 11 patients with a pubertal uterine configuration reverted to a more prepubertal-like morphology. The sonographic morphologic changes correlated well with laboratory and clinical data indicating suppression of the hypothalamic-pituitary-gonadal axis.

Child↗
PubMed1986

Pancreatic necrosis: CT manifestations.

Pancreatic necrosis is a potential sequela of acute pancreatitis, which pathologically represents a collection of devitalized tissue. Appropriate therapeutic planning requires definition of this irreversibly damaged gland, the presence of which is not consistently diagnosed on the basis of clinical and laboratory data. Over an 18-month period, 22 patients with pancreatic necrosis were studied by one or more computed tomographic (CT) examinations. Retrospective analysis showed the findings to vary with the developmental stage of the necrotizing process. During the acute phase, there was considerable morphologic overlap of necrosis and pancreatic phlegmon. Typical findings were seen in the subacute and chronic stages and included diffuse enlargement of the gland with largely decreased central density. A thick, smooth surrounding rim produced a characteristic saclike configuration. CT-guided aspiration for culture material was performed in four patients with suspected superinfection. Negative gram stain and culture results in two patients allowed surgery to be performed on a more elective basis.

Acute Disease↗
PubMed1986

Drainage of pelvic abscesses through the greater sciatic foramen.

A computed tomographic (CT) guided transgluteal approach through the greater sciatic foramen was used to drain pelvic abscesses and fluid collections in 21 patients. Ideal catheter placement should traverse the lower portion of the greater sciatic foramen at the level of the sacrospinous ligament. This avoids the vascular and neural elements that are located slightly cephalad at the level of the piriformis muscle. Percutaneous drainage through this approach was successful in avoiding surgery in 17 patients (81%). Pain was the most common complication and was generally associated with a more cephalad approach, transgressing the piriformis and the sacral plexus. CT-guided percutaneous drainage of pelvic abscesses through the greater sciatic foramen should be used when the more standard transperitoneal approach is not possible.

Abscess↗
PubMed1986

MR-guided aspiration biopsy: needle design and clinical trials.

Nonferrous needles of pure brass, titanium, or copper, and ferrous needles of different alloys of stainless steel were analyzed for the size, area, and distribution of the image artifact created when the needles were placed in a 0.6-T magnet. Results demonstrated that a stainless steel prototype needle (type 316) would be visible on magnetic resonance images and would provide an artifact similar to that seen in computed tomographic-guided biopsies. Further testing of this prototype included assessment of the effect on the artifact when changes were made in annealing properties, gauge, length, needle-tip geometry, pulse sequence, and orientation relative to the magnetic field. To date, three human liver biopsies have been successfully and safely performed using a stainless steel type 316 needle.

Aged↗