Direct integral linear least square regression method for kinetic evaluation of hepatobiliary scintigraphy: clinical application and evaluation of 170 hepatograms

Kinetic evaluation of 170 hepatobiliary scintigrams was performed using direct integral linear least square regression method (DILS method). Liver time-activity curve (TAC) data were fitted to 2 types of 1 compartment model using heart TAC as input function. One model was 1 compartment model with 2 parameters (extraction rate (ku) and excretion rate (ke)), the other had another parameter for representing non-specific volume of distribution (Vn) in liver. Obtained parameter estimate was then examined to see how they correlate with three major visual findings of scintigram; low tracer uptake, intrahepatic cholestasis, extrahepatic cholestasis. In both models, ku showed significant difference between low uptake positive and negative groups and ke showed significant difference between extrahepatic cholestasis positive and negative groups. Only mean uptake time (Vn/ku) by 3 parameter model showed significant difference between intrahepatic cholestasis positive and negative groups, although the other 2 parameters (ku, ke) were insensitive to intrahepatic cholestasis in either model. Thus, the 3 parameter model was superior to the 2 parameter model because of its sensitivity to intrahepatic cholestasis and ability to differentiate extrahepatic and intrahepatic cholestasis as the difference of parameter values. Based on this 3 parameter model, parametric images were generated by calculating parameter value of each pixel using the DILS method. The DILS method could determine parameters by simple calculation, and hence was very powerful in processing parametric images, which processing otherwise required immense calculation.     

Spin-spin relaxation in experimental allergic Encephalomyelitis. Analysis of CPMG data using a non-linear least squares method and linear inverse theory

We have used the CPMG pulse sequence to measure proton T₂ values and water content in spinal cord and brain samples from Hartley guinea pigs inoculated to produce experimental allergic encephalomyelitis (EAE). Relaxation data were fitted using minuit, a non-linear curve fitting routine. Three exponentials provided the best fit to spinal cord data (10 ms (13%), 76 ms (57%), 215 ms (30%)) and two exponentials for brain tissue (10 ms (4%), 92 ms (96%)). Least squares algorithms were also used to analyse the spinal cord data in terms of discrete and smooth distributions of relaxation times. The discrete least squares solutions consisted of three to five isolated spikes between 0.010 and 0.300 s. This type of solution was difficult to interpret in terms of water reservoirs. Smooth solutions consisted of two broad peaks, a small peak with a T₂ near 0.010 s and a larger peak near 0.100 s. The integral ratio of the larger to the smaller peak was 7.092 ± 1.782 for normal tissue, and increased to a maximum of 16 with increasing parenchymal cellular infiltration and demyelination. The short T₂ peak has been assigned to water in the hydration layers of the myelin sheath. The width of the longer T₂ peak was sensitive to tissue heterogeneity. The least squares and smooth distribution analysis models could be used to distinguish samples with extensive parenchymal infiltration from normal tissue, even though only a maximum of 60% of the tissue was affected. The short T₂ component could provide a direct method of measuring intact myelin, which would have a profound effect on the understanding of the evolution of pathology in multiple sclerosis.     

Cardiac autonomic modulation in judo athletes: evaluation by linear and non-linear method

Purpose

The practice of judo is associated with some heart conditions. Some authors suggest cardiac morphometric changes as an increase in diastolic dimension of the left ventricle, interventricular septum and posterior wall thickness of the left ventricle with an improvement in aerobic and anaerobic performance. However, few studies have explored the autonomic modulation by heart rate variability in judo athletes. The objective of this study was to evaluate the effect of judo training 6 months on autonomic modulation analysis, time and frequency domains symbolic.

Methods

The study included 16 young male, 18–25 years of age were recruited from university students through campus ads and divided into two groups: sedentary young males (S; n = 9) and judo (n = 7).

Results

There are no significant differences in age, height, weight, body mass index and heart rate among sedentary groups and judo. During the reporting period, sedentary individuals displayed parameters of the variability of the lower heart rate in the time domain, as SDNN, RMSSD, PNN50 and VarRR, compared with the subjects of judo. As the symbolic analysis it observed greater parasympathetic modulation (2UV) in judo group, compared with the sedentary group. However, no changes were observed in the sympathetic modulation (0V) between the groups.

Conclusions

We conclude that the exclusive practice of judo for 6 months produces autonomic changes, even without contributing to changes in body composition.

     

Estimation of gallbladder ejection fraction utilizing cholecystokinin-stimulated magnetic resonance cholangiography and comparison with hepatobiliary scintigraphy.

PURPOSE: To evaluate the utility of magnetic resonance cholangiography (MRC) in estimation of gallbladder ejection fraction (GBEF) and to comparing this value to the conventional method, hepatobiliary scintigraphy (HBS). MATERIALS AND METHODS: Twenty-one healthy volunteers were imaged on sequential weeks to determine GBEF using MRC and HBS. GBEF was calculated by HBS after infusion of 20 ng/kg of sincalide following injection of 111 Mbq of Tc 99(m) mebrofenin. For estimation by MRC, imaging of the gallbladder was performed before and after slow infusion of sincalide every 5 minutes, for a total of 60 minutes. Gallbladder imaging was performed using a heavily T2-weighted 2D fast spin echo (FSE) sequence. Data was analyzed using a variance component analysis technique. RESULTS: Mean GBEF by HBS was 65.7%, with an SD of +/-27.3%. Mean GBEF by MRC was 62.7%, with an SD of +/- 20.4%. If minimum normal GBEF is set at 35%, two of the cases showed discordance, with HBS calculating an abnormally low average GBEF compared to MRC. Additionally, two cases showed abnormally low GBEF for both modalities. The coefficient of correlation between HBS and MRC was 0.72. Inter- and intraobserver variance is acceptable within the two modalities with <1.1% variation. CONCLUSION: GBEF can be calculated with MRC, yielding similar values when a group of volunteers are considered. Further study with symptomatic patients is needed to determine the validity of this technique for clinical diagnosis.     

Diagnostic evaluation of cancer patients with pelvic pain: comparison of scintigraphy, CT, and MR imaging

Pelvic pain in cancer patients can result from several causes. The most appropriate choice of imaging techniques for evaluating such patients has not been established. We evaluated 27 cancer patients with pelvic pain by using radionuclide bone scintigraphy (24 patients), abdominal CT (27 patients), and pelvic MR imaging (27 patients) and used the correlation between symptoms and imaging findings to compare these imaging methods. The study population included 11 patients with Ewing sarcoma, six with other sarcomas, five with colorectal cancers, and five with other tumors. All patients had pelvic pain, and eight had pain radiating to a leg. Twenty-three patients had soft-tissue masses, and 19 had bone metastases; 16 had both. Findings on bone scans explained the symptoms in 17 (71%) of 24 patients, findings on CT in 23 (85%) of 27 patients, and findings on MR imaging in 25 (93%) of 27 patients. The difference between bone scanning and CT or MR was statistically significant (p less than .05); however, the difference between CT and MR imaging was not significant (p greater than .05). MR imaging detected 41 (98%) of 42 relevant lesions, whereas CT detected 31 (74%) of 42, and bone scanning 17 (44%) of 39. We conclude that MR is superior to either bone scanning or CT in the initial evaluation of pelvic pain in cancer patients. Such information can be important in directing the treatment of these patients.     

Primary sclerosing cholangitis: correlation of hepatobiliary scintigraphy with clinical and laboratory status

The aim of this study was to determine whether hepatobiliary scintigraphy using (99m)technetium based di-isopropryl-imino-diacetic acid correlated to clinical or laboratory status of patients with primary sclerosing cholangitis (PSC). We carried out a retrospective case-control study involving 15 patients with proven PSC. Fifty-seven hepatobiliary scintigraphic studies were reviewed by consensus of two experienced observers using a semiquantitative scheme to score liver size and degree of radiopharmaceutical uptake, intrahepatic or extrahepatic biliary stasis, segmental liver clearance half-times and gall bladder visualization. The results were compared with age; disease duration; weight loss; serum bilirubin, alkaline phosphatase and albumin levels; antipyrine clearance; number of biliary stents and episodes of cholangitis and history of transplantation. Sixteen age-matched and sex-matched individuals with PSC, who did not undergo hepatobiliary scans, were selected for comparison. Among the scintigraphic variables, right lateral and superior liver clearance half-time values showed a significant linear correlation with disease duration and serum alkaline phosphatase levels (P < 0.05) but not with other clinical or biochemical indices. Other scintigraphic variables showed no correlation. An abnormal, hepatobiliary scan liver clearance half-time in patients with PSC correlates to disease duration and increased serum alkaline phosphatase levels, and this variable may be used to identify some subjects with more advanced disease.     

Evaluation of results of the prostigmine-morphine test with quantitative hepatobiliary scintigraphy: a new method for the diagnosis of sphincter of Oddi dyskinesia

Attempts have long been made to use the prostigmine-morphine provocation test for the selection of postcholecystectomy patients suffering from sphincter of Oddi (SO) dyskinesia. Since the whole procedure is based upon the evaluation of subjective complaints, this test has frequently been criticized. To improve the diagnostic value of this method, we have visualized SO spasms during prostigmine-morphine provocation by means of quantitative hepatobiliary scintigraphy (QHBS). Twenty-two cholecystectomized patients with typical postprandial biliary pain were included in this study. In the first series of studies, QHBS with technetium-99m 2,6-diethylphenylcarbamoylmethyl-diacetic acid was performed in each patient 2 days before prostigmine-morphine provocation. The time to peak activity (T _max) and the half-time of excretion (T _1/2) over the liver parenchyma (LP), hepatic hilum (HH) and common bile duct (CBD), and the duodenum appearance time (DAT), were determined and served as control values. In the second series of experiments, sphincter spasms were evoked by prostigmine-morphine administration and visualized by means of QHBS. The same parameters were evaluated and serum levels of aspartate aminotransferase (AST) were determined simultaneously at regular intervals. In 12 patients who responded to prostigmine-morphine provocation with typical biliary pain and a significant AST elevation (Nardi positive group) the hepatobiliary scintigram demonstrated a marked biliary obstruction.T _max andT _1/2 over the LP, HH and CBD were significantly increased, while DAT was significantly longer relative to the corresponding data obtained without provocation. Four of the remaining ten patients indicated atypical abdominal pain during prostigmine-morphine provocation, but the AST level remained unchanged in all ten (Nardi negative group). In this group, QHBS revealed a slower, but free transpapillary flow of the tracer: althoughT _1/2 over the LP, HH and CBD appeared to be significantly higher than without provocation,T _max did not change and an obstructive pattern was not detected on the hepatobiliary scintigram. When QHBS parameters determined during prostigmine-morphine provocation were compared for the Nardi positive and Nardi negative groups, with the exception ofT _max over the LP they were significantly different. QHBS combined with the prostigmine-morphine provocation test proved to be a useful non-invasive method for the detection of pathological sphincter spasms in patients with SO dyskinesia. Application of this method is therefore strongly recommended in the diagnosis of SO dyskinesia.     

Reproducibility of linear tumor measurements using PACS: comparison of caliper method with edge-tracing method

The aim of this study was to evaluate inter- and intra-observer reproducibility when making electronic caliper linear tumor measurements on picture archiving and communications systems (PACS) and compare them with linear measurements obtained from circumferential tracing of tumor perimeter. Three radiologists measured 64 masses from 30 patients on body CT scans in two separate settings. Long axis and perpendicular short axis were measured using electronic calipers. The edge of each tumor was traced electronically and the long and short axes were calculated by computer software. The reproducibility of a measurement was evaluated by computing and comparing the absolute value of the mean difference between initial and subsequent measurements. The mean differences ±95% confidence interval (CI) between two measurements of the long by short axis were 3.8±2.6×3.1±1.8 mm when the caliper method was used and 3.5±2.0×3.2±1.5 mm when the tumor tracing method was used. There was no statistically significant difference in individual intra-observer reproducibility of tumor axes measurements. Neither long- nor short-axis single-dimension measurements resulted in significantly greater or lesser intra-observer reproducibility. When comparing caliper and tracing measurements, the overall mean difference (3.42±1.8 vs 3.38±1.4 mm) was not statistically significant. There was close correlation between the individual measurements made by each observer whether these were made by electronic calipers and when these were calculated from electronic tracings (Pearson correlations between 0.79 and 0.949). Current PACS systems allow reproducible linear, long or short axis, tumor measurements. There is no significant difference in reproducibility of measurements whether these are made directly with electronic calipers or calculated from tumor edge tracings.     

Postsurgical diagnostic evaluation of patients with differentiated thyroid carcinoma: comparison of ultrasound, iodine-131 scintigraphy and PET with fluorine-18 fluorodeoxyglucose

PURPOSE: The aim of this study was to compare the results of ultrasound (US), whole-body scintigraphy with iodine-131 (I-131 WBS) and positron emission tomography with fluorine-18 deoxyglucose (FDG-PET) in the follow-up of patients after thyroidectomy for differentiated thyroid carcinoma (DTC). MATERIALS AND METHODS: Thirteen patients (3 men, 10 women) were evaluated by neck US, I-131 WBS and FDG-PET. In each patient six anatomical regions (right and left thyroid bed, right and left cervical region, right and left supraclavicular region) were investigated, for a total of 78 regions. Distant metastases were investigated by I-131 WBS and FDG-PET and considered separately in the analysis. Imaging findings were compared with the reference standards, such as fine-needle aspiration cytology (2), biopsy (4) or clinical-radiological studies (7). RESULTS: US, FDG-PET and I-131 WBS showed concordant negative results in most (70, 90%) of the anatomical sites considered. In one patient with left cervical lymph node metastasis, the imaging techniques showed concordant positive results (1%). In the remaining 7 regions (9%), the imaging results were discordant; in particular, tumour lesions, nodal metastases (4) and thyroid bed recurrences (3) were detected by US only (3), by US and I-131 WBS (1) and by FDG-PET only (3). With regard to distant metastases, FDG-PET and I-131 WBS yielded concordant negative results in the majority (77%) of patients (9); in one patient only were the two imaging techniques concordant in their positive result. In the last three patients, the results were discordant; in particular, distant metastases were detected by I-131 WBS only in two patients and by FDG-PET only in one patient. CONCLUSIONS: Our work indicates a fundamental role for US in evaluation of the neck after surgery for DTC. WBS is useful to determine differentiation of tumour lesions, to identify thyroid remnants and to look for distant metastases. FDG-PET has an important role in cases of dedifferentiated thyroid carcinoma in which WBS and thyroglobulin measurements are unable to detect tumour lesions.     

Hyperparathyroidism: A comparison of sestamibi scintigraphy,mri, and ultrasonography

For patients with persistent or recurrent hyperpara-thyroldism, parathyroid imaging is indicated to confirm the presence of abnormal parathyroid gland(s) and identify their location. These imaging techniques are being modified constantly and newer methods have been developed. Sestamibi scintigraphy, MRI and sonography were compared in 23 patients with persistent or recurrent hyperparathyroidism. Preoperative 99m-Technetium Sestamibi (MIBI), MRI and ultraaono-graphic (US) studies of 23 patients with 25 histopatho-logically confirmed abnormal parathyroid glands were compared, using independent prospective interpretations. All patients had been operated upon previously for hyperparthytroidism. Accuracy of various combinations of MRI. MIBI, and US also were calculated. The results are shown for all abnormal glands (n = 25): sensitivities and accuracies were 88 and 84% for MRI. 80 and 80% for MIBI. and 58 and 44% for US. For only parathyroid adenomas (n = 18). sensitivities and accuracies were 89 and 89% for MRI, 94 and 94% for MIBI. and 58 and 39% for US. Finally, for parathyroid hyperplasla (n = 7 glands in five patients), sensitivities and accuracies were 83 and 71% for MRI. 43 and 43% for MIBI, and 57 and 57% for US. Either MIBI or MRI results were significantly better for detecting abnormal parathyroid glands than US (P <0.01), but MRI and MIBI were not statistically different. Combining MRI and MIBI produced a combined accuracy of 92%, whereas combining either of these tests with US did not improve on the accuracy of either test alone. In conclusion, for patients with persistent or recurrent hyperparathyroidism, MRI and MIBI are equally accurate for detecting abnormal parathyroid glands, and the combination of both tests may be more accurate than either test alone.     

Whole body PET for the evaluation of bony metastases in patients with breast cancer: comparison with 99Tcm-MDP bone scintigraphy

The purpose of this study was to determine the potential role of positron emission tomography (PET) using 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) for the evaluation of bony metastasis compared with 99Tcm-methylene diphosphonate (99Tcm-MDP) bone scintigraphy in patients with breast cancer. Fifty-one female patients with breast cancer who had PET together with a bone scan within 1 month between September 1994 and March 1997 were included in this study. The median age was 49 years (range 29-79 years). The sensitivity, specificity and accuracy of the bone scan were 77.7%, 80.9% and 80.3%, respectively. On the other hand, for the detection of bone metastases PET had a sensitivity, specificity and accuracy of 77.7%, 97.6% and 94.1%, respectively. In the diagnosis of bony metastasis derived from breast cancer, FDG-PET was statistically superior to bone scintigraphy in its specificity. In conclusion, FDG-PET appears to be a powerful tool not only in the diagnosis of the primary lesion and soft tissue metastasis, but also in the diagnosis of bony metastasis among patients with breast cancer.     

Ileoanal pouches: comparison of CT, scintigraphy, and contrast enemas for diagnosing postsurgical complications

The value of CT of the pelvis, 111In-labeled leukocyte scintigraphy, and contrast enema (pouchography) for detecting postsurgical complications was assessed in 44 patients with total colectomy, rectal mucosectomy, and ileoanal pouches. Ileoanal pouches were created as reservoirs from an ileal loop that was anastomosed to the dentate line of the anus and stayed connected to the remainder of the ileum. This pouch preserves the normal defecatory pathway and eliminates disease-producing mucosa. A total of 57 sets of examinations revealed 22 cases of normal postoperative findings, 22 of pouchitis, 13 of abscess, and three of fistula. Overall sensitivity for detecting complications with pouchography was 60% (18 of 30 findings); with CT, 78% (28 of 36 findings); and with scintigraphy, 79% (23 of 29 findings). Pouchitis was best diagnosed by scintigraphy (sensitivity, 80%), followed by CT (sensitivity, 71%) and pouchography (sensitivity, 53%). Only CT correctly diagnosed all cases of abscess. Fistulas were frequently missed by all three methods. If tests were combined, the overall sensitivity rose to 93% for the combination CT/scintigraphy and to 86% for CT/pouchography, but did not improve for pouchography/scintigraphy (78%). For evaluation of complications in patients with ileoanal pouches, CT should be the initial test. If an abscess is found, no further tests are needed. If CT findings are negative, a scintigram should be obtained. Our data did not establish a clear role for pouchography.     

A case of recurrent cholangitis after bile duct injury during laparoscopic cholecystectomy: Value of scintigraphy with Tc-99m GSA and hepatobiliary scintigraphy for indication of lobectomy

A 39-year-old woman with acute cholecystitis and gallstones underwent laparoscopic cholecystectomy. She suffered from recurrent episodes of cholangitis due to injury of the major bile ducts during laparoscopic cholecystectomy. Hepatobiliary scintigraphy with Tc-99m Sn-N-pyridoxyl-5-methyltryptophan was performed. Although normal bile excretion was found from the left hepatic duct to the percutaneous transhepatic biliary drainage (PTBD) tube, excretion from the right hepatic lobe was prolonged. Scintigraphy with Tc-99m diethylenetriaminepentaacetic acid-galactosyl human serum albumin demonstrated atrophy of the right hepatic lobe and enlargement of the left hepatic lobe. Cholangiography via the PTBD tube revealed complete obstruction of the left hepatico-jejunal anastomosis and could not enhance the right intrahepatic bile duct. A right hepatic lobectomy was performed because of the atrophy, glissonitis and the absence of an appropriate bile duct for reconstruction. Postoperatively she was active and exhibited no evidence of recurrent cholangitis.