Development of comparative methods using gas chromatography-mass spectrometry and capillary electrophoresis for determination of endocrine disrupting chemicals in bio-solids

Two analytical separation techniques are being investigated for their potential in determining a wide range of endocrine disrupting chemicals (EDCs) in the environment. Capillary electrophoresis (CE) in the micellar mode in conjunction with a cyclodextrin (CD) modifier is shown to have potential for determination of alkylphenol breakdown products. Gas chromatography with mass spectrometric (GC-MS) detection is being utilised for validation of the CE method development and in addition as a separation technique to optimise preconcentration using solid-phase extraction. GC has demonstrated potential for the separation of 26 priority chemicals suspected as being endocrine disrupting compounds. The challenge of the method development process lies in the fact that these compounds are of differing polarities, size and charge and therefore are difficult to separate in a single run. Capillary electrophoresis in the CD-MEKC (micellar electrokinetic chromatography) mode is showing potential in this regard. Limits of determination are in the low mg/l range for CE and GC, however, using preconcentration it is possible to improve detection sensitivity with >80% recovery for some analytes and up to 100% recovery for most target species.

Plain abdominal x-ray versus computerized tomography screening: sensitivity for stone localization after nonenhanced spiral computerized tomography

PURPOSE

Urolithiasis followup with plain abdominal x-ray requires adequate visualization of the calculus on the initial x-ray or computerized tomography (CT) study. We compared the sensitivity of plain abdominal x-ray versus CT for stone localization after positive nonenhanced spiral CT.

MATERIALS AND METHODS

We evaluated 46 consecutive nonenhanced spiral CT studies positive for upper urinary tract lithiasis for which concurrent plain abdominal x-rays were available. X-ray and CT studies were compared for the ability to visualize retrospectively a stone given its location by CT. A consensus of 1 radiologist and 3 urologists was reached in each case. Cross-sectional stone size and maximum length were measured on plain abdominal x-ray.

RESULTS

Plain abdominal x-ray and scout CT had 48% (22 of 46 cases) and 17% (8 of 46) sensitivity, respectively, for detecting the index stone (p <0.00004). Of the 39 stones overall visualized on plain abdominal x-ray only 19 (49%) were visualized on scout CT. Mean cross-sectional area and length of the stones on scout CT were 0.34 cm.2 (approximately 6 x 5.5 mm.) and 6. 5 mm., respectively, while the average size of those missed was 0.11 cm.2 (approximately 4 x 3 mm.) and 3.6 mm. The mean size differences in the groups were highly significant (p <0.0009).

CONCLUSIONS

Plain abdominal x-ray is more sensitive than scout CT for detecting radiopaque nephrolithiasis. Of the stones visible on plain abdominal x-ray 51% were not seen on CT. To facilitate outpatient clinic followup of patients with calculi plain abdominal x-ray should be performed when a stone is not clearly visible on scout CT.

Hypereosinophilic sclerosing cholangitis: findings using half-Fourier magnetic resonance imaging

Hypereosinophilic sclerosing cholangitis is a rare disease caused by eosinophilic infiltration of the gallbladder and biliary tract seen in the idiopathic hypereosinophilic syndrome. We report a 42-year-old woman who presented with symptoms of cholecystitis and obstructive cholangitis. Imaging with magnetic resonance cholangiography using a half-Fourier spinecho sequence, we were able to visualize rapidly and non-invasively a severely abnormal gallbladder, evidence of liver parenchymal inflammation, and biliary duct dilatation.

MR cholangiopancreatography using HASTE sequences

AIM

The aim of this pictorial review is to describe applications of cholangiopancreatography (MRCP) using half-Fourier (HASTE) MR sequences.

MATERIALS AND METHODS

350 patients were imaged over a four-year period with a 1.54 Tesla Siemens Vision scanner and a phased array body coil. The HASTE MR sequence was applied in multiple planes with an acquisition time of 13 seconds allowing breath hold techniques. In addition, a single-shot technique provided single slice acquisitions with a thickness of 20 mm. A chemical fat suppression algorithm reduced intra-abdominal MR high signal.

RESULTS

HASTE MRCP accurately determines the presence of level of biliary obstruction in up to 97% of patients. Common bile duct stones are detected with a sensitivity of 93%. Acute cholecystitis is depicted on HASTE MR as pericholecystic high signal in 41/45 (91%) patients and gall stones are detected with a 93% sensitivity.

CONCLUSION

HASTE MRCP offers a non-invasive, rapid imaging method to evaluate the gallbladder, common bile duct and pancreas. Its multi-planar, fluid sensitive capabilities are of particular value in detecting common bile duct stones and acute cholecystitis.

Ventilation-perfusion scintigraphic evaluation of pulmonary clot burden after percutaneous thrombolysis of clotted hemodialysis access grafts

The objective of this study is to determine, by using rigorous methods, if pulmonary perfusion defects were detectable by ventilation-perfusion scintigraphy after percutaneous thrombolysis of clotted hemodialysis access grafts. Thirteen patients were studied. Four patients underwent pharmacomechanical thrombolysis with urokinase and the remainder had mechanical thrombolysis alone. Pre- and postthrombolysis scintigraphic studies were performed on all patients. Perfusion defects were described as vascular (well-defined borders confined to segmental boundaries) or nonvascular. Vascular defects were graded by severity (0 to 3) and area (0 to 3) for each involved segment. Nonvascular defects were graded by severity (0 to 1) and area (0 to 1). Two experienced readers evaluated the scans blinded to each other's results and all other clinical data, including thrombolysis outcomes. Twelve patients did not have any significant worsening of their perfusion defect scores postthrombolysis. In only one patient did a study show a new nonvascular perfusion defect with a matching ventilation abnormality. The defect was believed to be caused by mucus plugging. The patient had no evidence of pulmonary embolism. Our study suggests emboli that resulted from the pharmacomechanical or mechanical thrombolysis procedure were either small, underwent lysis before impacting the lung, or were below the limit of detection of ventilation-perfusion scintigraphy.

Cerebral embolism after mechanical thrombolysis of a clotted hemodialysis access

Clinically significant embolic complications after thrombolysis of clotted hemodialysis grafts are uncommon. Most of the concern has focused on the risks associated with pulmonary emboli. We report a case of a hemodialysis patient who developed a cerebral embolism after percutaneous graft thrombolysis who was found to have a patent foramen ovale and intermittent right-to-left shunt.

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.

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.

Hydronephrosis in pregnancy: simultaneous depiction of fetal and maternal hydronephrosis by magnetic resonance urography

Magnetic resonance urographic (MRU) techniques possess image quality and diagnostic capability that are improving with increasingly sophisticated imaging sequences and shorter scanning times. We describe the application of a fast breath-hold MR sequence (HASTE) in the assessment of ureteric obstruction in pregnancy. In the patient presented, HASTE MRU was successful in depicting ureteral anatomy and demonstrated dilation of both ureters below the level of the pelvic brim. This observation suggested distal ureteral obstruction rather than simple hydronephrosis of pregnancy. As a result, bilateral nephrostomies were performed and neonatal prematurity was avoided. Interestingly, in this patient, HASTE MR imaging also showed evidence of concurrent fetal hydronephrosis.

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.

Hepatomegaly and multiple liver lesions

Images

The diagnostic utility of HASTE MRI in the evaluation of acute cholecystitis. Half-Fourier acquisition single-shot turbo SE

PURPOSE

The purpose of this study was twofold: (a) to determine the significance of high signal intensity surrounding the gallbladder as seen on T2-weighted HASTE (half-Fourier acquisition single shot turbo SE) MR images in patients with acute cholecystitis and (b) to determine the sensitivity of T2-weighted HASTE MR images in detecting gallbladder and common bile duct (CBD) calculi in patients with acute cholecystitis.

METHOD

Seventy-two patients with a suspicion of acute cholecystitis were referred for HASTE MRI over a 2 year period. Forty-one patients underwent MRI after sonography and the remaining 31 patients before sonography. MR images were independently evaluated for the presence of MR pericholecystic high signal and gallbladder and CBD calculi. Findings were correlated with results obtained at sonography and at surgery.

RESULTS

Of the 72 patients imaged with HASTE MRI, 55 had cholecystitis based on clinical, sonographic, and/or surgical findings. Of these, 45 had acute and 10 had chronic cholecystitis. HASTE MRI demonstrated MR pericholecystic high signal in 41 of 45 (91%) of the patients with acute cholecystitis. The sensitivity of HASTE MRI in diagnosing acute cholecystitis was 91%. The specificity was 79%. The positive predictive value was 87%, the negative predictive value was 85%, and the overall accuracy of the test was 89%. Gallbladder stones were seen by HASTE MRI in 38 of 41 (93%) of patients with acute calculus cholecystitis demonstrated at sonography. CBD stones were demonstrated by HASTE MRI in seven of nine (78%) patients and by sonography in five of nine (56%) patients with documented choledocholithiasis on conventional cholangiography.

CONCLUSION

HASTE MRI has a high degree of accuracy in diagnosing acute cholecystitis based on the single finding of pericholecystic MR high signal. A similar level of accuracy is demonstrated in detecting gallbladder stones. Biliary duct calculi are detected with even greater accuracy than with sonography in patients with acute cholecystitis. Invasive preoperative endoscopic retrograde cholangiography may therefore be limited to only those patients with acute cholecystitis and CBD stones demonstrated on HASTE MRI. These features make HASTE MRI and ideal imaging modality in the initial evaluation of acute biliary pain and may ultimately replace sonography in the preoperative evaluation of acute cholecystitis.

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.

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.

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.

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.

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.