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Biomedical subjects

K Koster

Publications and source records attributed to K Koster.

16 recordsLinked to original sources
PubMed2003

Magnetic resonance cholangiopancreaticography as a diagnostic tool for common bile duct stones: a comparison with ERCP and clinical follow-up.

BACKGROUND/AIMS: The diagnostic potential of magnetic resonance cholangiopancreaticography (MRCP) has improved as a result of evolving technique. MRCP has the advantage of negligible morbidity and mortality in contrast to endoscopic retrograde cholangiopancreatography (ERCP). This study was performed to evaluate MRCP as a replacement for diagnostic ERCP for the suspicion of common bile duct (CBD) stones. METHODS: From 1998 to 2001, MRCP was performed in 202 patients with a suspicion of CBD stones based on medical history (MH), cholestatic liver function tests (CL), both MH and CL or other reasons. ERCP was performed in all patients where MRCP indicated the presence of CBD stones and in those patients with a persistent strong clinical suspicion for CBD stones despite a negative MRCP. RESULTS: In 25 patients, MRCP suggested CBD stones which were proven with ERCP in 24 patients. Despite a negative MRCP, 27 patients had a subsequent ERCP. None of these patients appeared to have CBD stones. In this group, MRCP resulted in 100% sensitivity and 96% specificity in detecting CBD stones. Follow-up of all patients revealed 5 more patients with persistent clinical suspicion or cholestatic liver function values. Assuming CBD stones in these patients, MRCP had a sensitivity of 83 % and a specificity of 99% for this diagnosis. CONCLUSION: In the case of CBD stone suspicion, MRCP should be the diagnostic procedure of choice.

Adult↗
PubMed2001

[Magnetic resonance cholangiopancreatography: sensitive and specific diagnostic method for suspected choledolithiasis].

OBJECTIVE: To evaluate the role of magnetic resonance pancreaticography (MRCP) in the diagnostic process of common bile duct stones. DESIGN: Retrospective. METHOD: All 27 MRCPs performed in the period December 1997-December 1998 in the Deventer Hospital, the Netherlands, were evaluated using chart examination. The group comprised 11 males and 16 females with an average age of 57 years (SD 3.2) with anamnestic or biochemical cholestasis. If at MRCP stones were diagnosed, endoscopic retrograde cholangiopancreaticography (ERCP) was performed. If MRCP was without abnormalities, no further diagnostic procedures were performed. The findings at MRCP were compared with those at ERCP and with the clinical course. The MRCP examinations were performed on a 1.5 Tesla MR unit. RESULTS: In 16 patients MRCP was performed before laparoscopic cholecystectomy and in 5 there after. In 5 MRCP was performed to rule out a biliary cause of acute pancreatitis and in 1 patient because of an elevated alkaline phophatase after laparotomy for an abdominal stab injury. There was one false-positive MRCP result and no false-negative ones. Accordingly, the sensitivity of MRCP for choledocholithiasis was 100% and the specificity 95%.

Cholangiography↗
PubMed2001

HDR brachytherapy applied to cervical carcinoma with moderate lateral expansion: modified principles of treatment.

BACKGROUND AND PURPOSE: In order to meet the deficiencies of endocavitary applications, a combined technique was introduced with the aim of achieving better target coverage for improvement of loco-regional tumour control. In high dose rate (HDR) endocavitary applications with tandem and ovoids, enlargement of the distance between the ovoids, shifting of dwell times and also optimization often fail to achieve sufficient expansion of the cervical parametrial area encompassed by the reference isodose. MATERIALS AND METHODS: The Deventer method, whereby HDR endocavitary and HDR interstitial brachytherapy are applied in the same session, was applied for tumours with a lateral expansion of 25 mm or more from the axis of the cervical canal. For the addition of HDR interstitial brachytherapy, each ovoid was provided with a channel which allowed insertion of an afterloading needle into the cervix up to a fixed depth. The dose specifications and dosimetry in neighbouring organs are presented in detail. RESULTS: Seventy-six combined applications were given to 41 patients. The follow-up averaged at 23 months, with a maximum of 59 months. No severe early or persistent late complications were observed. In stage IIB tumours, the most important evaluation of the merits of this technique, the disease-free 3-year survival determined with the Kaplan-Meier method was 75% (n=20). CONCLUSIONS: The Deventer method of HDR endocavitary and HDR interstitial brachytherapy applied in the same session is a feasible method for enlargement of the reference isodose envelope in the cervical parametrial area. The 3-year disease-free survival in stage IIB patients and the low complication rates in all stages together, justify its continuation.

Adult↗
PubMed1999

Electroconvulsive therapy in adolescents: experience, knowledge, and attitudes of recipients.

OBJECTIVE: To ascertain the experience, knowledge, and attitudes regarding electroconvulsive therapy (ECT) of persons who received the treatment in adolescence. METHOD: A 53-item survey was administered by telephone to persons who received ECT before the age of 19 years in the Australian state of New South Wales between 1990 and 1998. RESULTS: Twenty-six patients were interviewed. Experiences and opinions about ECT were generally positive. Fifty percent stated ECT had been helpful. Approximately three quarters believed their illness was worse than either ECT or pharmacotherapy. Frequencies of recalled side effects with ECT and medication were similar. Some patients perceived deficiencies in the consent process. A slight majority had attempted to conceal the history of ECT treatment. The vast majority considered ECT a legitimate treatment and, if medically indicated, would have ECT again and would recommend it to others. CONCLUSIONS: The findings are consistent with and complement evidence showing ECT to be an effective and safe treatment for seriously ill adolescents. The mostly favorable experiences and attitudes reported by interviewees will be reassuring to adolescent patients, their families, and treating health professionals when ECT is being considered.

Adolescent↗
PubMed1999

Views about treatment among parents of adolescents who received electroconvulsive therapy.

The study assessed the experience, knowledge, and attitudes of parents of adolescents who had been treated with electroconvulsive therapy (ECT) about that treatment. Twenty-eight parents were interviewed. Overall, their opinions about ECT were favorable. Seventeen of 28 parents thought that ECT had been helpful. If ECT was recommended by a doctor, the vast majority of parents would support a decision for their child to have the treatment again and would advise others to consider it.

Adolescent↗
PubMed1991

Visual stimulation increases technetium-99m-HMPAO distribution in human visual cortex.

The ability of changes in the distribution of technetium-99m-hexamethylpropylene amine oxime (99mTc-HMPAO) to reflect physiologic changes in regional cerebral blood flow (rCBF) was evaluated using photic stimulation, a procedure known to increase rCBF in the striate cortex. Seven healthy subjects were injected with 740 MBq 99mTc-HMPAO on two separate days. On one day, the injection was performed following closure of the eyes and patching for 5 min. On the other day, subjects were exposed to a stroboscopic light to produce photic simulation. Images of distribution of 99mTc-HMPAO were obtained using a Strichman 810X single-photon emission computed tomogram (SPECT) brain scanner. Comparison of images obtained during light occluded versus stimulation conditions revealed a significant increase in distribution of radiopharmaceutical in visual cortex relative to whole brain (peak increase corrected for radiopharmaceutical backdiffusion 36.7% +/- 6.6%). HMPAO appears to provide a useful method for detecting relative rCBF increases with SPECT.

Adult↗
PubMed1990

Patients at high risk for renal artery stenosis: a simple method of renal scintigraphic analysis with Tc-99m DTPA and captopril.

Fifty patients with suspected renal artery stenosis (RAS) were studied with renal scintigraphy before and after administration of captopril. Twenty-three patients had RAS (greater than or equal to 75% RAS or greater than or equal to 50% RAS with poststenotic dilatation) and 27 had normal renal arteries at angiography. Angiotensin-converting enzyme inhibitors were discontinued 24 hours prior to renal scintigraphy; all other medications were continued. Each patient was evaluated with a simplified captopril renal scintigraphic protocol: renal imaging after administration of 12 mCi (444 MBq) of technetium-99m diethylenetriaminepentaacetic acid (DTPA), a 3-hour wait, oral administration of 50 mg of captopril, a 1-hour wait, and another scintigram obtained after administration of 12 mCi (444 MBq) of Tc-99m DTPA. Times of peak renal activity (Tmax) were determined from renal time-activity curves, and glomerular filtration rates (GFRs) were calculated with the Gates technique. A Tmax greater than or equal to 11 minutes after injection or a GFR ratio (larger GFR/smaller GFR) greater than 1.5 enabled detection of RAS with 91% sensitivity, 93% specificity, and 92% accuracy. Renal scintigraphy without captopril had only 43%-68% sensitivity in detecting RAS, depending on the criteria used.

Captopril↗
PubMed1990

Quantitative analysis of planar technetium-99m-sestamibi myocardial perfusion images using modified background subtraction.

Standard interpolative background subtraction, as used for thallium-201 (201Tl), may create artifacts when applied to planar technetium-99m-Sestamibi (99mTc-Sestamibi) images, apparently because of the oversubtraction of relatively high extra-cardiac activity. A modified background subtraction algorithm was developed and compared to standard background subtraction in 16 patients who had both exercise-delayed 201Tl and exercise-rest 99mTc-Sestamibi imaging. Furthermore, a new normal data base was generated. Normal 99mTc-Sestamibi distribution was slightly different compared to 201Tl. Using standard background subtraction, mean defect reversibility was significantly underestimated by 99mTc-Sestamibi compared to 201Tl (2.8 +/- 4.9 versus -1.8 +/- 8.4, p less than 0.05). Using the modified background subtraction, mean defect reversibility on 201Tl and 99mTc-Sestamibi images was comparable (2.8 +/- 4.9 versus 1.7 +/- 5.2, p = NS). We conclude, that for quantification of 99mTc-Sestamibi images a new normal data base, as well as a modification of the interpolative background subtraction method should be employed to obtain quantitative results comparable to those with 201Tl.

Algorithms↗
PubMed1987

Early disappearance of lymphatics draining ischemic myocardium in the dog.

To assess myocardial lymphatics during the evolution of myocardial infarction we performed lymphangiographic studies thirty and three hundred sixty minutes after occlusion of the left anterior descending coronary artery in 92 dogs. A morphometric index was employed on a coded basis to assess the lymphangiograms. Well before myocardial necrosis was evident, at thirty minutes, a striking reduction was evident in lymphatic filling in the ischemic zone: similar changes were seen three hundred sixty minutes after occlusion. Heparin in doses that rendered blood incoagulable did not prevent the lymphatic occlusion or collapse, but they were prevented by two agents that act as cardiac lymphagogues, hyaluronidase and CLS 2210. Lymph flow from the heart was assessed in another 23 dogs. Lymph flow fell sharply after coronary artery occlusion in placebo-treated dogs but was well maintained in dogs treated with hyaluronidase and with CLS 2210. The reduction in cardiac lymphatic filling and lymph flow occurred too early to be a consequence of myocardial necrosis. To the extent that reduced lymphatic drainage allows the local accumulation of potentially toxic products, it could contribute to the local damage. Treatment with the lymphagogues not only maintained lymphatic patency but also reduced evidence of myocardial damage evident on examination by light and electron microscopy. These studies provide an alternative to commonly held concepts on how hyaluronidase reduces myocardial infarction after coronary artery occlusion and support the concept that lymphatic occlusion or collapse plays a role in myocardial infarction.

Animals↗
PubMed1986

Clinical response to coronary artery reoperations.

Repeat coronary artery bypass operations were performed on 112 patients at a university hospital between 1971 and 1981. When compared with patients who did poorly after a first operation but did not have repeat surgery, patients undergoing repeat surgery tended to be younger, to have a higher smoking rate and to have fewer prior myocardial infarctions, fewer diseased vessels and fewer lesions in distal vessels. At least 1 graft was occluded in 83% of patients undergoing reoperation, and a mean of 1.7 grafts were placed at reoperation. The operative mortality rate was 4%, with a follow-up mortality rate of 6% at a mean of 3.8 years. After reoperation, patients initially showed improvement to a mean specific activity scale class of 1.6, compared with 2.4 before the first operation and 2.7 before the second operation. The principal correlate of a better long-term symptomatic response compared with that in the period before the first operation was a lower serum cholesterol level, whereas the principal correlate of a better symptomatic response compared with that in the period just before the reoperation was the left ventricular ejection fraction. As recurrent symptoms after a first coronary artery operation become more prevalent, consideration of the selection factors and prognostic correlates of reoperation will become increasingly important.

Coronary Angiography↗
PubMed1983

Computed tomography of malignant pleural mesothelioma.

We tabulated the computed tomographic (CT) findings in 14 consecutive patients who had proven malignant pleural mesotheliomas and were studied over a 3-year period. We also staged the disease in these patients, all of whom were men, aged 40-75 years (mean, 59), and had been exposed to asbestos at work. Common presenting symptoms were shortness of breath or chest pain. Pleural thickening was found on the side of the tumor in all of the patients, characterized as nodular and circumferential (6/14 cases), plaque-like (4/14), or strictly nodular (4/14) in appearance. In addition, 86% of the patients demonstrated contralateral pleural thickening, but these lesions did not prove to be tumor deposits. Other common CT findings in the involved hemithorax included: pleural effusions (79% of cases), lung parenchymal disease (79%), decreased hemithorax size (62%), and pleural calcification (50%). Before the chest scans were performed, 13 patients were felt to have Stage I disease and one to have Stage IV. The CT information revised these opinions: four of the Stage I patients were assigned to Stage II (on the basis of chest wall involvement or enlarged hilar/mediastinal lymph nodes). Therapy was altered in these four cases. In two patients pericardial thickening was seen, but it was not possible to determine if this was due to tumor involvement. We conclude that CT can identify several abnormalities that are commonly associated with mesotheliomas. By demonstrating lesions not detectable on conventional imaging studies, CT may alter staging and therapy in many patients with this disease.

Adult↗
PubMed1978

Conservative management of uremic pericardial effusions.

Although there has been a recent trend toward early operative treatment of uremic pericardial effusions unresponsive to intensified dialysis, this approach may be unnecessarily aggressive. Review of 787 patients in our chronic dialysis program since 1969 has shown 54 patients (6.9 percent) to have developed 56 episodes of large pericardial effusion. All were managed by increasing the frequency of dialysis. If the effusion failed to diminish or if life-threatening signs of tamponade developed, pericardiocentesis was performed. In 63 percent (35/56) the effusion resolved with increased dialysis. In 37 percent (21/56), pericardiocentesis was performed, with 57 percent (12/21) requiring only one aspiration. During a mean follow-up of 34 months (2 to 100 months) only 5.5 percent (3/54) have undergone operation: one partial pericardiectomy incidental to pulmonary decortication and two pericardiectomies for late (3 months and 5 months, respectively) constriction. There were five complications of pericardiocentesis: one pneumothorax, one pneumoperitoneum, one costochondritis, and two myocardial punctures without sequelae. The one death related to pericardial effusion in this series occurred in a home-dialysis patient who arrived in the emergency room moribund. Our experience suggests that the great majority of uremic pericardial effusions can be effectively controlled with simple needle aspiration by experienced personnel and that pericardial resection is usually not necessary.

Adolescent↗