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Biomedical subjects

F Regan

Publications and source records attributed to F Regan.

At least 37 records · Page 2Linked to original sources
PubMed1999

Utility of magnetic resonance cholangiography in the evaluation of biliary obstruction.

BACKGROUND: Evaluation of suspected biliary obstruction has traditionally involved a variety of imaging modalities including ultrasound, CT, and invasive cholangiography. These techniques have limitations because of poor visualization of intraductal stones (ultrasound and CT) and the need for an invasive procedure (ERCP and percutaneous transhepatic cholangiography). Magnetic resonance cholangiography (MRC) is a noninvasive imaging modality that provides good visualization of the hepatobiliary system. The aim of the present study was to determine the utility of MRC in evaluating patients with suspected biliary obstruction. STUDY DESIGN: One hundred forty-three patients were identified with suspected acute biliary obstruction and underwent MRC. Patient selection was based on clinical criteria including an elevation in serum liver chemistries or evidence of biliary ductal dilatation on conventional imaging. MRC was performed using a half-Fourier acquisition single-shot turbo spin-echo sequence involving single breath-hold rapid image acquisition. A final diagnosis was determined in each patient based on invasive cholangiography, findings at surgery, and clinical course. RESULTS: Of the 143 patients, 73 had an obstructing biliary lesion. A malignant process was identified in 25 patients with final diagnoses of pancreatic cancer (n = 15), ampullary cancer (n = 4), cholangiocarcinoma (n = 3), and hepatic or nodal metastases (n = 3). MRC correctly identified biliary obstruction in all these patients and accurately identified the level of biliary obstruction in 24 of 25 patients. Based on the MRC images alone, a malignant process was suspected in 21 of the 25 patients. Forty patients were found to have common bile duct stones and eight patients had a benign distal bile duct stricture. MRC correctly identified common bile duct stones in 37 patients with one false-positive exam (sensitivity = 92%; specificity = 99%). MRC also correctly identified distal biliary strictures in eight patients. In the remaining 70 patients, no definite biliary obstruction was identified by MRC, and in all patients the absence of mechanical obstruction was confirmed by invasive cholangiography or overall clinical course. CONCLUSIONS: This study demonstrates that MRC is able to accurately identify the level and cause of biliary obstruction in both malignant and benign disease. MRC may prove to be an important noninvasive tool in preoperative evaluation of patients with suspected biliary obstruction and identification of patients most likely to benefit from an invasive radiologic or surgical procedure.

Adolescent↗
PubMed1999

Clinical applications of half-Fourier (HASTE) MR sequences in abdominal imaging.

Endoscopic retrograde cholangiography remains a valuable technique in biliary disease, because therapeutic intervention, such as stone extraction and biliary drainage, can be carried out at the same time as diagnosis. Spatial resolution is superior to that of noninvasive imaging methods. HASTE MR cholangiopancreatography is as sensitive as sonography in detecting cholelithiasis. It is superior to sonography in diagnosing common bile duct stones, malignant biliary obstruction, and benign pancreatic disease. The noninvasive nature of HASTE MR imaging insures an expanding role in imaging patients with suspected pancreaticobiliary disease.

Abdomen↗
PubMed1998

Indium-111 capromab pendetide (ProstaScint) imaging to detect recurrent and metastatic prostate cancer.

This study evaluated the utility of In-111 capromab pendetide imaging to detect prostate cancer metastases or local recurrence. The specific goal was to identify clinical factors such as prostate-specific antigen, pathologic stage, and Gleason score that were most predictive of a positive scan outcome. In addition, a new concept of a weighted Gleason score was defined and correlated with the scan outcome. Fifty-one patients with an elevated prostate-specific antigen level and otherwise negative workup were studied. Forty-eight patients had been treated by radical prostatectomy, two by radiation therapy, and one patient was studied before prostatectomy. Each patient received an intravenous injection of approximately 5 mCi of In-111 containing 0.5 mg of CYT 356, a conjugated site-specific monoclonal antibody against prostate specific membrane antigen. Tomographic blood pool images were obtained the day of injection. Four days later planar images and tomographic images of the abdomen and pelvis were obtained. Scans were interpreted by two experienced nuclear medicine physicians. Differences in the scan interpretation were settled by consensus. Scan outcomes were correlated with prostate-specific antigen levels, pathologic stage, Gleason score, weighted Gleason score, and clinical data. Of 51 scans, 70.6% (36 of 51) were positive. Eight patients had abnormal activity in the prostatic fossa, 12 patients had abnormal activity in the abdominal or pelvic lymph nodes, and 16 patients demonstrated abnormal activity in both areas. One patient with a positive scan underwent lymphadenectomy and was confirmed to be a true positive. Patients with a prostate-specific antigen level greater than 10 ng/ml, a weighted Gleason score higher than 4.5, or prostate-specific antigen levels greater than 2 ng/ml plus a weighted score higher than 4.5 showed positive rates of 100% (6 of 6), 88.2% (14 of 16), and 100% (6 of 6), respectively. In-111 capromab pendetide imaging was useful to detect metastases or local recurrence. Serum prostate-specific antigen levels and weighted Gleason scores are good predictive factors of the likelihood of a positive scan outcome.

Abdominal Neoplasms↗
PubMed1998

Fast MR imaging and the detection of small-bowel obstruction.

OBJECTIVE: Our aim was to determine whether fast MR imaging using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) MR sequence is accurate for diagnosis of small-bowel obstruction. MATERIALS AND METHODS: Forty-three nonconsecutive patients with suspected small-bowel obstruction were evaluated with HASTE MR imaging during a 12-month period. Images were retrospectively assessed for the presence, level, and cause of bowel obstruction. Data were compared with results of conventional radiography and findings at surgery when available. RESULTS: Of the 43 patients imaged, 29 patients had small-bowel obstruction revealed by unenhanced or contrast-enhanced radiography or by CT. Surgical confirmation was available in 21 patients. Small-bowel obstruction was shown by HASTE MR imaging in 26 (90%) of these 29 patients. HASTE MR images showed the correct level of obstruction in 19 (73%) of the 26 patients and showed the cause of obstruction in 13 (50%) of the 26 patients. CONCLUSION: With a high degree of accuracy, HASTE MR imaging can show the presence and level of small-bowel obstruction.

Adult↗
PubMed1997

Perirenal MR high signal--a new and sensitive indicator of acute ureteric obstruction.

PURPOSE: This study was carried out to determine the incidence of perirenal magnetic resonance (MR) high signal in acute ureteric obstruction as demonstrated by half-Fourier acquisition single shot turbo spin-echo (HASTE) MR. In addition, we evaluated the sensitivity of this perirenal MR high signal as a predictor of acute ureteric obstruction. MATERIALS AND METHODS: A prospective evaluation of 55 consecutive patients with suspected ureteric obstruction was carried out using the HASTE MR sequence. Images were compared to concurrent IV urography (IVU) or to computed tomography (CT) where these were available. Acute and chronic ureteric obstruction were differentiated by clinical evaluation. RESULTS: Forty-one patients had obstructed kidneys. HASTE MR accurately predicted the presence of acute ureteric obstruction in 20/23 (87%) based on presence of perirenal MR high signal. None of these showed evidence of contrast medium extravasation on the concurrent i.v. urogram. 15/18 (83%) chronically obstructed kidneys demonstrated no perirenal high signal on HASTE MR, and the remaining three showed only a trace of perirenal high signal. CT showed perirenal stranding in only 2/8 patients with acutely obstructed kidneys. CONCLUSION: In acute ureteric obstruction, HASTE MR shows perirenal high signal intensity much more commonly than IVU shows extravasation or CT showing perirenal stranding. The origin of this MR signal is uncertain but may represent oedema, lymphatic distension or free fluid from forniceal rupture. HASTE MR can accurately distinguish between acute and chronic ureteric obstruction based on the degree of perirenal high signal.

Acute Disease↗
PubMed1997

Comparison of in vivo red cell survival of donations collected by Haemonetics MCS versus conventional collection.

The Haemonetics Multicomponents System (MCS) cell separator allows concurrent donation of red cells in addition to platelets and/or plasma, thus increasing the versatility of apheresis donations. In vivo survival of autologous red cells obtained by MCS was compared with red cells collected conventionally. In this cross-over controlled study, five male volunteers donated one unit of red cells by MCS and one unit of whole blood by the conventional manual method, 3 months apart. After storing donations in SAG-M for 35 days under standard conditions, radioactive (51Cr)-labelled autologous red cells were injected into each donor. The post-transfusion recovery (PTR) of red cells at 24 and 48 h did not show any significant difference between red cells obtained manually and by MCS, indicating that processing differences have no detrimental effects on red cell survival.

Blood Donors↗
PubMed1997

The role of computerized tomography in the evaluation of complications after laparoscopic urological surgery.

PURPOSE: Radiographic evaluation may be necessary to assess the possible complications of laparoscopic procedures. We undertook a retrospective review to determine the indications for and findings of computerized tomography (CT) in symptomatic patients after urologic laparoscopic surgery. MATERIALS AND METHODS: Of 400 laparoscopic urological procedures performed between July 1993 and September 1996, 20 patients (5%) had postoperative symptomatology that could not be explained by physical exam or routine clinical studies. An abdominal CT scan was obtained (1 to 120 days after the procedure) to help determine a diagnosis. CT findings were correlated with the indication for the study and clinical followup. RESULTS: The indications for CT were unexplained pain, fever, leukocytosis or falling hematocrit. Thirteen patients had significant findings related to their surgery that were identified by CT. In 2 cases, we identified pathology unrelated to the surgery. Therefore, CT identified a symptom-related diagnosis in 75% of patients (15 of 20). Each scan for decreasing hematocrit demonstrated a hematoma. In all patients with unexplained fever or leukocytosis, CT revealed the cause. CT evaluation of atypical postoperative pain demonstrated a pathological cause in 58% (7 of 12). Percutaneous or laparoscopic surgical intervention was required in 4 of 20 patients. In 8 patients scanned by postoperative day 6, intraperitoneal or retroperitoneal gas was identified in 3 who had an abdominal incision made for intact specimen removal and in 1 with a perforated ulcer. CONCLUSIONS: CT after urologic laparoscopy is indicated in patients with significant clinical findings in whom routine examination and tests are not diagnostic. CT can reliably identify postoperative bleeding, urinary leak or obstruction and can also detect nonurinary pathology.

Adult↗
PubMed1996

A prospective study of the incidence of red cell allo-immunisation following transfusion.

To establish the incidence and timing of red cell allo-immunisation following transfusion, pretransfusion and serial post-transfusion samples were screened for allo-antibodies in a total of 452 patients who had undergone elective surgery. Antibody screening was performed by 2-stage papain, manual polybrene and indirect antiglobulin techniques (IAT). Red cell allo-antibodies were found in 42 patients and 38 of these (8.4% overall) demonstrated antibodies only after transfusion; 76% of them had Rh specificity. This rate of red cell allo-immunisation is higher than what would be expected if transfused patients were tested only once post-transfusion, as has been the case in several previous studies. For the type of patients studied, this finding may not be of clinical relevance at present because most patients undergoing elective surgery do not require further transfusion in their lifetime. However, this is changing with the longer life expectancy of the population and the increased probability of repeat surgery. Twenty-two (58%) of the antibodies were initially detected by the 2-stage papain and/or polybrene techniques, when the IAT was negative, although later 19 became positive by IAT; this added sensitivity of techniques other than the IAT, to detect early allo-immunisation may be relevant in pretransfusion testing to prevent haemolytic transfusion reactions in patients requiring repeated transfusions.

Adult↗
PubMed1996

MR urography using HASTE imaging in the assessment of ureteric obstruction.

OBJECTIVE: The purpose of this study was to evaluate an MR sequence using half-Fourier acquisition single-shot turbo spin-echo (HASTE) imaging in the assessment of ureteric obstruction. SUBJECTS AND METHODS: We prospectively evaluated 111 kidneys in 56 consecutive patients with HASTE MR urography and compared that imaging technique with excretory urography. The HASTE sequence was used to acquire images in the axial, sagittal, and coronal planes while patients held their breath. Level of obstruction and ureteric diameter were assessed, and the time required to determine the level of obstruction by both techniques was noted. RESULTS: With HASTE MR urography, we correctly diagnosed obstruction in 41 (100%) of 41 kidneys. Of the obstructed kidneys in which the ureter was shown by both excretory urography and MR urography, agreement was high (kappa = .642) between the two imaging techniques regarding the level of obstruction. HASTE MR urography showed perirenal fluid in 20 (87%) of 23 acutely obstructed kidneys. HASTE MR urography showed the site of obstruction on the first 13-sec scan in 33 (80%) of 41 kidneys. CONCLUSION: HASTE MR urography accurately and rapidly shows the level and degree of ureteric obstruction. It can be used to differentiate between acute and chronic obstruction on the basis of its ability to show perirenal fluid.

Acute Disease↗
PubMed1996

Choledocholithiasis: evaluation with MR cholangiography.

OBJECTIVE: We performed this study to evaluate the usefulness of a new T2-weighted MR sequence using a half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique in the diagnosis of bile duct stones. SUBJECTS AND METHODS: We prospectively evaluated 23 patients with suspected bile duct calculi using HASTE MR cholangiography and compared that imaging technique with endoscopic retrograde cholangiography and sonography. The study group consisted of 15 women and eight men who were 42-89 years old. Patients were imaged in the axial, coronal, and sagittal planes with a 1.5-T MR scanner using a body coil. Acquisitions of 13 sec each allowed images to be obtained in a single breath-hold. All images were interpreted by two radiologists in a double-blinded fashion. The presence, number, and size of stones were noted, and common bile duct dilatation was assessed. RESULTS: Fifteen of the 23 patients were proven to have common bile duct stones. Stone size ranged from 3 mm to 35 mm (mean, 11 mm). HASTE MR cholangiography revealed stones in 14 (93%) of 15 patients; sonography revealed stones in nine (60%) of 15 patients. In 12 patients, the common bile duct was dilated, as shown by endoscopic retrograde cholangiography, HASTE MR cholangiography, and sonography. On HASTE MR cholangiograms, we measured the diameter of the bile duct in all patients. The mean diameter was 11 mm, which correlated well (r = .82) with a mean diameter of 13.5 mm as measured on endoscopic retrograde cholangiograms. CONCLUSION: HASTE MR cholangiography can noninvasively and rapidly reveal the presence of stones in the common bile duct and allows readers to assess the degree of biliary dilatation. The sequence should be considered as an alternative to endoscopic retrograde cholangiography in patients with clinical evidence of bile duct calculi and in those for whom endoscopic retrograde cholangiography is impossible.

Adult↗
PubMed1996

Minimally invasive management of acute superior mesenteric artery occlusion: combined urokinase and laparoscopic therapy.

Acute superior mesenteric arterial occlusion is a medical emergency mandating prompt diagnosis and therapy. Traditional management includes exploratory laparotomy with possible embolectomy or bowel resection. Unfortunately, these patients are often frail and elderly and tolerate open laparotomy poorly. In this report, we describe a patient with acute superior mesenteric artery occlusion successfully managed with a minimally invasive approach. The acute arterial occlusion was managed with intra-arterial fibrinolytic therapy, and bowel viability was assessed with diagnostic laparoscopy. This combined approach of arteriographic and laparoscopic therapy avoided exploratory laparotomy, and we believe that it is an important therapeutic option in select patients with acute mesenteric ischemia.

Acute Disease↗