Biomedical subjects

J F Simeone

Publications and source records attributed to J F Simeone.

At least 55 records · Page 3Linked to original sources

PubMed1986

Preoperative evaluation of abdominal aortic aneurysms by computed tomography.

A prospective, preoperative study was conducted of 50 electively repaired abdominal aortic aneurysms comparing the CT and angiographic findings with those described at surgery. CT demonstrated all 50 aneurysms and correctly identified their proximal extent in relation to the takeoff of the renal arteries in 47 patients (94%), while angiography detected 48 aneurysms (96%) and their correct relation to the renal arteries in all (100%). CT correctly identified 40 (98%) of 41 patients with two renal arteries, but only two (29%) of seven with three and none of two patients with four arteries. Common iliac artery involvement or lack thereof was accurately predicted in 42 (84%) of the 50 patients and internal iliac artery aneurysms found in one (33%) of three patients. It was concluded that CT is not sufficiently accurate for documenting location and patency of the renal arteries to allow its routine substitution for angiography in patients undergoing preoperative assessment of abdominal aortic aneurysms.

Aged↗

PubMed1986

Staging rectal cancer by MR and CT.

Sixteen patients with known rectal cancer were evaluated and staged with CT and MR, and at surgery. Detailed evaluation of the pathologic specimens was performed and correlated with CT and MR to determine the accuracy of staging. Most of the cases were advanced stages, and both CT and MR were equally effective in staging. Prone positioning using an air-distension technique was equally important for CT and MR examinations. Because of a positive contrast material (iodine), adequate CT examinations could be performed without prior bowel preparation; however, bowel cleansing was necessary for MR examinations. Both techniques could identify the primary tumor and invasion into perirectal fat and local organs. Neither CT nor MR were able to assess the extent of bowel-wall infiltration or tumor spread to normal size perirectal lymph nodes.

Air↗

PubMed1986

Microbubbles as a contrast agent for neurosonography and ultrasound-guided catheter manipulation: in vitro studies.

Tissue-equivalent ultrasound phantoms, including models of the ventricular system and cyst phantoms, may be useful for developing expertise in both biopsy procedures and shunt catheter placement that use ultrasound guidance. These phantoms have been constructed (1) to assess the ability to position biopsy needles and manipulate shunt catheters with conventional angiographic guidewires and (2) to evaluate the usefulness of microbubbles as an ultrasound contrast agent. Optimal catheter and needle position and catheter patency are demonstrated with microbubbles generated by hand injection of small volumes of saline, a safe ultrasound contrast agent that, to our knowledge, has not been previously exploited in neurosonography. Microbubbles can define biopsy needle location without direct imaging of the biopsy needle; they can also define the extent of communication or separation of fluid-filled or loculated spaces.

Air↗

PubMed1986

Percutaneous drainage of subphrenic abscess: a review of 62 patients.

Sixty-two patients who presented with subphrenic abscesses had the abscesses drained percutaneously. Diagnosis of a subphrenic collection was usually made with sonography. Initial percutaneous drainage was accomplished with a combination of sonography and fluoroscopic guidance. More recently (in the last 31 cases) most drainages were done with sonographic guidance alone. Successful catheter drainage was achieved in 85% with a complication rate of 4.8%. Failure of catheter drainage (defined as any patient who was not cured by percutaneous drainage alone) occurred in patients with multiple collections or in whom the primary cause of the abscess necessitated surgery, for example, perforated ulcer, acute cholecystitis. Considerations for successful drainage include understanding the anatomy of the subphrenic space, recognizing the importance of a correct access route (avoidance of the pleura and lung), and the long time necessary for adequate drainage (longer than 10 days in 60%). An angled subcostal approach to the subphrenic space was used in 56 (90%) of 62 cases. No complications occurred in this group. The one pneumothorax that occurred in the remaining six cases was a direct result of using an intercostal approach through the parietal pleura into a subphrenic collection. We conclude that percutaneous drainage is a safe and effective method of treatment of subphrenic abscesses.

Catheterization↗

PubMed1985

The bile ducts after a fatty meal: further sonographic observations.

The sonographic appearance of the response of the common hepatic duct to physiologic stimulation by a fatty meal was assessed in 131 patients referred because of right upper quadrant symptoms or abnormal liver chemical studies. In the determination of the presence or absence of biliary obstruction, the sensitivity of the examination was 84%, the accuracy of a positive test was 84%, and the accuracy of a negative test was 93%. This test proved helpful in several circumstances: equivocal duct caliber (6-10 mm); abnormal caliber (6-14 mm) with normal laboratory values; normal caliber duct with abnormal laboratory values; persistent question of cholelithiasis or asymptomatic pancreatic duct dilatation. Measurements of bile duct caliber alone may be insufficient to ascertain the presence of bile duct obstruction and fatty meal stimulation significantly improves diagnostic accuracy.

Bile Ducts↗

PubMed1985

Lesser sac abscesses and fluid collections: drainage by transhepatic approach.

Twelve abscesses and fluid collections in the lesser peritoneal sac were drained percutaneously using an access route across the intervening liver. This rather unusual access was chosen when other approaches were contraindicated because of surrounding colon, stomach, or spleen. All collections were drained successfully, and no specific complications such as hemorrhage, bile leak, or liver abscess occurred. Placement of an abscess drainage catheter should be done through the peripheral portion of the liver if possible. The technique offers a new, safe approach to percutaneous drainage of hitherto inaccessible collections.

Abscess↗

PubMed1985

Intrahepatic amebic abscesses: indications for and results of percutaneous catheter drainage.

Medical therapy is standard for intrahepatic amebic abscess and generally is effective. However, we have encountered a group of patients in whom percutaneous aspiration and drainage was indicated due to uncertainty of diagnosis or clinical deterioration of the patient. Twenty such patients underwent percutaneous drainage with ultrasound or CT guidance, and each patient was cured (appropriate antibiotics were administered concomitantly). The specific indications for intervention were to differentiate pyogenic from amebic abscess, pain and imminent rupture, poor response to medical therapy, false-negative results of serologic tests, noncompliance with medical treatment, left lobe abscess, and pregnancy. Diagnosis of amebiasis from examination of the fluid was seldom possible, while findings from core biopsy of the wall of the abscess led to diagnosis in three cases. Recurrence necessitating redrainage occurred in three patients; in each, catheters were removed the same day drainage was performed. There were three minor complications. Differences from percutaneous management of pyogenic abscesses included more rapid removal of catheters (four days), more frequent use of US guidance, and more common use of the prone angled approach to avoid pleural contamination. Catheter drainage may be curative and may expedite care for problematic amebic liver abscesses in selected cases.

Adult↗

PubMed1985

Surface coil MR imaging of abdominal viscera. Part I. Theory, technique, and initial results.

Prototype surface coil magnetic resonance (MR) images were obtained from phantoms and 42 subjects at 0.6 T to assess the feasibility of imaging relatively deep abdominal structures. Surface coil images demonstrated a two- to fourfold improvement in signal-to-noise ratio (SNR) when compared with whole-body coil images with the same resolution elements. This improvement in SNR allowed us to obtain images with thinner sections, higher in-plane resolution, or, alternatively, a decrease in image time. Compared with body images, surface coil images demonstrated greater anatomic detail and reduction in motion artifacts. Despite the limited field of view in very large patients, the use of surface coils improves the diagnostic capability of MR imaging of the abdomen.

Abdomen↗

PubMed1985

Surface coil MR imaging of abdominal viscera. Part II. The adrenal glands.

Magnetic resonance (MR) imaging of the adrenal glands with a prototype surface coil was compared with conventional body coil images in five healthy volunteers and 15 patients with adrenal disease. The spectrum of abnormalities included five nonfunctioning cortical adenomas, of which two were in hyperplastic glands, four adrenal metastases, three pheochromocytomas, a functioning adenoma, a myelolipoma, and a partially calcified, cystic adrenal mass. In both body and surface coil images, anatomic detail was superior on T1-weighted images compared with T2-weighted images obtained with identical imaging time because of decreased motion artifact and superior contrast. In the T1-weighted studies, high-resolution surface coil images showed a threefold improvement in signal-to-noise ratio (SNR) over body coil images, which was manifest by better intrinsic resolution of small adrenal lesions and clearer definition of the extrinsic relationships of large masses to nearby organs. In addition, inferior vena caval invasion by two right adrenal metastases was better demonstrated using the surface coil than body coil MR or computed tomography (CT). Limitations of surface coil imaging include restriction in the field of view to a single gland and additional time required for patient positioning. Since the sensitivity of surface coils diminishes with depth, gains in SNR were limited in large patients with deeper adrenal glands. Despite these limitations, dramatic improvements in SNR and anatomic resolution indicate that surface coil MR imaging will be competitive with CT for examining the adrenal glands.

Adrenal Gland Diseases↗

PubMed1985

Surface coil MR imaging of abdominal viscera. Part III. The pancreas.

Eight healthy volunteers and 11 patients with pancreatic abnormalities were studied using a conventional body coil and a prototype magnetic resonance (MR) surface coil. Final pathologic diagnoses included carcinoma of the head (six), body (one), and tail of the pancreas (two) and chronic pancreatitis (two). In surface coil images of the volunteers, the body and tail of the pancreas was visualized in all cases but one, and the pancreatic duct was seen in five of eight cases. In-plane spatial resolution of 0.9 X 0.9 mm and 5-mm section thickness was obtained. At the same time, pancreatic surface coil images had a twofold improvement in the signal-to-noise ratio (SNR) compared with body coil images. T1-weighted spin-echo images gave greater SNR, reduced motion artifacts, provided superior anatomic detail, and offered more diagnostic information than comparable T2-weighted images. Significant abnormalities detected only by surface coil imaging included a small tumor surrounded by reactive edema and periglandular tumor invasion. This study demonstrates that surface coil imaging of the pancreas not only is feasible but provides an improved method for examining the pancreas by MR.

Adult↗

PubMed1985

Gallbladder bile in cholecystitis: in vitro MR evaluation.

Fifty-three samples of gallbladder bile were obtained at the time of cholecystectomy from patients with the clinical diagnosis of acute or chronic cholecystitis. Five bile samples from patients with clinically normal gallbladders also were obtained. Proton magnetic resonance (MR) relaxation times, protein content, and water content were determined for the bile samples, and the data were grouped according to pathologic diagnosis, which disclosed 11 cases of acute cholecystitis, 41 cases of chronic cholecystitis, and six normal gallbladders. There was no significant difference in the mean T1 and T2 values between the groups with acute and chronic cholecystitis. Patients with chronic cholecystitis were found to have more concentrated bile than those with acute cholecystitis. Protein content varied widely within both groups of patients. We conclude that T1 and T2 relaxation times do not reliably differentiate acute from chronic cholecystitis.

Bile↗

PubMed1985

Comparison of sonography and plain films in evaluation of the acute abdomen.

In 95 patients with acute abdominal pain seen in the emergency ward of a large urban teaching hospital, real-time sonography was performed in conjunction with a plain film of the abdomen in order to detect what, if any, added information was provided by the sonographic examination. In 20 patients (21%) the sonogram contributed important diagnostic information not provided by the plain film of the abdomen. Most of these patients had pathology referable to the biliary tract (14 of 20). In 28 patients (30%), the sonogram confirmed the diagnosis by abdominal film. In 39 (41%) the sonogram added no relevant information, and in three (3%) it was deleterious. In five (5%) the plain film provided more information than the sonogram.

Abdomen, Acute↗

PubMed1985

Presacral masses after abdominoperineal resection for colorectal carcinoma: the need for needle biopsy.

Computed tomographic(CT)-guided biopsy of presacral masses after abdominoperineal resection for colorectal carcinoma was performed in 28 patients, using a transgluteal approach. The masses were divided into three groups according to their morphologic appearance: solid mass, mass with central low-density area, and gas-containing mass. Of 19 patients with a homogeneous solid mass, 15 had biopsy-proven recurrent adenocarcinoma. In the other nine patients, who had low-density masses with or without gas, it was not possible to offer a diagnosis on the basis of the CT appearance alone. In these cases, needle biopsy disclosed various entities, including recurrent tumor, abscess, and posttreatment necrosis. There was only one complication, transient hematuria. CT-guided needle biopsy of presacral masses after abdominoperineal resection is a simple, relatively safe, and valuable diagnostic technique.

Adenocarcinoma↗

PubMed1985

Percutaneous drainage of pyogenic liver abscesses.

This report summarizes the results of percutaneous catheter drainage in 23 cases of primary or secondary pyogenic liver abscess. The overall success rate was 76%. Only three (60%) of five cases of secondary abscess (infected hematoma or infected tumor) were cured with catheter drainage, but 11 (91%) of the last 12 primary pyogenic abscesses were drained successfully. Six patients with abscesses of less than 4 cm in diameter required catheter drainage for less than 72 hr. Although six abscesses in the series appeared septated or multiloculated, only one required more than a single catheter for curative drainage. Diagnostic and technical considerations for successful drainage of hepatic abscesses are discussed. The differential diagnosis includes echinococcal disease and hepatic amebiasis. Therapeutically, specific measures should be taken to ensure proper catheter position to prevent contamination of the subphrenic, perihepatic, and pleural spaces. Percutaneous catheter drainage should be attempted as a first choice of treatment in all pyogenic hepatic abscesses.

Diagnosis, Differential↗

PubMed1985

Magnetic resonance imaging of cavernous hemangioma of the liver: tissue-specific characterization.

Twenty-one patients with hepatic hemangioma, five with hepatic cysts, and 25 with primary or metastatic cancer involving the liver were studied by magnetic resonance imaging (MRI). Benign lesions (hemangiomas, cysts) were diagnosed noninvasively by CT, radionuclide studies, and/or sonography and confirmed by follow-up examinations more than 1 year later. Malignant lesions were confirmed by liver biopsy in every case. Identical multisection/multiecho techniques were used in all patients to obtain T1-and T2-weighted spin-echo (SE) and inversion-recovery (IR) images. MRI detected more hemangiomas than any other imaging technique. Of 30 hemangiomas, 25 were spherical or ovoid with a homogeneous appearance and smooth, well defined margins. Cancer tended to have a heterogeneous appearance and poorly defined margins. On T2-weighted SE images obtained with 2000 msec TR and 60, 120, or 180 msec TE, hemangiomas had significantly greater contrast-to-noise ratios (C/N) than liver cancer (p less than 0.001). The SE 2000/120 sequence provided the single most useful image for distinguishing hemangiomas from cancers. When morphologic criteria are used in conjunction with measured C/N, MRI correctly distinguished cavernous hemangiomas from liver cancer with 90% sensitivity, 92% specificity, and an overall accuracy of 90%. Cysts had a low signal intensity on SE 500/30 images and could often be distinguished from hemangiomas and cancers that were nearly isointense relative to liver. IR images were sensitive for lesion detection but provided no tissue-specific information. The data indicate that T2-weighted SE imaging may become the procedure of choice for distinguishing cavernous hemangioma from liver cancer.

Adenoma, Islet Cell↗

PubMed1985

Inadvertent percutaneous catheter gastroenterostomy during abscess drainage: significance and management.

Eleven cases of inadvertent catheter insertion into the small bowel or stomach during percutaneous abdominal abscess drainage are reviewed. Recognition of the intraluminal catheter position was made by contrast-enhanced fluoroscopy in all patients 1-6 days after catheter insertion. No evidence of leakage of intestinal contents into the peritoneal cavity was noted either clinically or radiologically. All cases occurred after drainage of a centrally located midabdominal collection, but the ultimate outcome was not compromised. In nine of 11 cases, catheter drainage alone was sufficient; two cases required additional surgical drainage. Considerations for management include a prolonged period of catheter drainage to allow evolution of a fibrous tract and gradual catheter withdrawal. These data confirm the growing experience with purposeful percutaneous gastrostomy that percutaneous catheterization of the gastrointestinal tract can occur without major sequelae.

Abdomen↗

PubMed1985

Percutaneous drainage of postoperative abdominal and pelvic lymphoceles.

Eleven patients with postoperative abdominal and pelvic lymphoceles underwent percutaneous diagnostic and therapeutic intervention with either needle aspiration or catheter drainage. Although initial sonographic or CT examinations accurately identified these collections, definitive diagnosis required fluid sampling and laboratory analysis for confirmation. Seven pelvic and two retroperitoneal lymphoceles demonstrated a gross appearance and composition different from two lymphatic collections in the upper peritoneum. Nine patients underwent catheter drainage; two were managed by needle aspiration alone. Duration of catheter drainage was 4-120 days, substantially longer than is customary for standard fluid collections. Nine of 11 patients were cured by percutaneous aspiration or drainage alone. Bacterial colonization developed in three persistently draining lymphoceles. However, no clinical sepsis or bacteremia occurred. In another patient with persistent high-volume lymphatic output, sclerotherapy with tetracycline instillation was successful in rapidly closing the lymphatic fistula. Percutaneous drainage is a safe, effective procedure for drainage of postoperative lymphoceles.

Adult↗

PubMed1985

Portable ultrasound examinations in intensive care units.

The portability of modern real-time ultrasound units has led to a marked increase in the demand for examinations in medical, surgical, and pediatric intensive care units, the pediatric nursery, and the operating room. The results of all portable ultrasound examinations in the medical and surgical intensive care units at the Massachusetts General Hospital over a four-month period were analyzed to determine the efficacy of such studies. Of 48 examinations, portable sonograms were useful in 90 per cent, found new, clinically important information in 17 per cent, and led to misleading information in 4 per cent. Portable ultrasound examinations are valuable clinically and are probably cost effective.

Boston↗