Non-linear quantum-classical scheme to simulate non-equilibrium strongly correlated fermionic many-body dynamics.

We propose a non-linear, hybrid quantum-classical scheme for simulating non-equilibrium dynamics of strongly correlated fermions described by the Hubbard model in a Bethe lattice in the thermodynamic limit. Our scheme implements non-equilibrium dynamical mean field theory (DMFT) and uses a digital quantum simulator to solve a quantum impurity problem whose parameters are iterated to self-consistency via a classically computed feedback loop where quantum gate errors can be partly accounted for. We analyse the performance of the scheme in an example case.

Reliability of Doppler ultrasound in follow-up studies.

PURPOSE: To evaluate the reliability of repeat Doppler US measurements. MATERIAL AND METHODS: Nine radiologists conducted two sets of Doppler US measurements on a healthy volunteer, with a time interval of 9 months. Peak systolic velocity (PSV), resistance index (RI), and pulsatility index (PI) were measured 10 times in 4 arteries. RESULTS: There was considerable intra- and inter-observer variation both at baseline and 9 months later. The PSV values from the carotid artery varied from 0.27 m/s to 1.95 m/s in February and from 0.22 m/s to 1.38 m/s in November. The RI values from the renal artery ranged from 0.44 to 0.71 in February and from 0.41 to 0.67 in November. The results of the 9-month follow-up varied markedly too. Best reproducibility was achieved by highly experienced radiologists both at baseline and 9 months later. CONCLUSION: The short-term and long-term reliability of Doppler US was poor when the measurements were performed by a heterogeneous group of radiologists. The RI and PI measurements were somewhat more reliable than the PSV measurements and are recommended for use in follow-up studies.

Long-term prognosis of reactive salmonella arthritis.

OBJECTIVES: Reactive joint complications triggered by salmonella gastroenteritis are increasingly reported, but the outcome and long term prognosis of the patients is incompletely known. This study looked at the prognosis of salmonella arthritis in patients hospitalised in 1970-1986. METHODS: Hospital records from two hospitals in southern Finland were screened for patients with the discharge diagnosis of salmonellosis or reactive, postinfectious arthritis or Reiter's disease. For the patients with confirmed diagnosis of reactive salmonella arthritis, data about the acute disease were collected from the hospital records. A follow up study was performed. RESULTS: There were 63 patients (28 women, 35 men, mean age 36.5 years) with salmonella arthritis. Urethritis occurred in 27%, eye inflammation in 13%, and low back pain in 44% of the patients. HLA-B27 was present in 88%. More men than women were HLA-B27 positive. HLA-B27 positive patients had higher erythrocyte sedimentation rate (mean 80.9 v 46.5 mm 1st h, p = 0.0180). Also, extra-articular features and radiological sacroiliitis were seen only in HLA-B27 positive patients. A follow up study was performed on 50 patients mean 11.0 (range 5-22 years) later. Twenty patients had recovered completely. Ten patients had mild joint symptoms, 11 patients had had a new acute transient arthritis, and five acute iritis. Eight patients had developed chronic spondyloarthropathy. Radiological sacroiliitis was seen in six of 44 patients, more frequently in male than in female patients (32% v 0%; p = 0.0289). Recurrent or chronic arthritis, iritis or radiological sacroiliitis developed only in HLA-B27 positive patients. CONCLUSION: Joint symptoms are common after reactive salmonella arthritis. HLA-B27 contributes to the severity of acute disease and to the late prognosis.

Peak systolic velocity, resistance index and pulsatility index. Variations in measuring a pre-recorded videotape.

PURPOSE: To study variation in the process of measuring Doppler ultrasound (US) wave forms. MATERIAL AND METHODS: Eleven radiologists measured peak systolic velocity (PSV), resistance index (RI), and pulsatility index (PI) from a pre-recorded videotape. The wave forms were taken from the carotid, brachial, celiac, and renal interlobar arteries in a healthy volunteer. Each radiologist obtained measurements 10 times from a freely chosen wave form of 10 wave forms (10-beat series) and then a further set of measurements also 10 times from a specific wave form (1-beat series). RESULTS: There was a significant variation in all the PSV, RI and PI values measured, both in the 1-beat series and in the 10-beat series. The greatest variation was seen in the PI values: up to 5.1-fold. Both intraobserver and interobserver reproducibilities were poor. CONCLUSION: The process of obtaining measurements from an identified wave form is a major source of error in Doppler US studies. Special attention should be paid to this final phase of an examination. We recommend that measurements be obtained from more than one heart beat.

Reproducibility of Doppler ultrasound measurements.

PURPOSES: The reproducibility of Doppler ultrasound measurements was studied in a group of radiologists with different experience of such measurements. MATERIAL AND METHODS: The 12 participating radiologists measured peak systolic velocity (PSV), resistance index (RI), and pulsatility index (PI) from 3 arteries and PSV alone in one artery of a healthy person under standardized circumstances. Each participant repeated the measurements 10 times. RESULTS: Significant (p < 0.005) interobserver variation was seen in all of the variables, with an up to 14-fold difference in the PSV values measured and most variation resulting from differences between observers. The reproducibility of RI was better, most variation being within observers. Experience improved the reproducibility of the Doppler US measurements. Significant difference (p < 0.05) in Doppler US measurements was seen between the 3 experience groups. The difference was marked between the highly experienced and the medium experienced group when the variances of the measured values of PSV, RI, and PI from all 4 arteries were combined. CONCLUSION: The reproducibility of Doppler ultrasound measurements is poor. The value of the method is questionable.

Painful ankle region in rheumatoid arthritis. Analysis of soft-tissue changes with ultrasonography and MR imaging.

PURPOSE: To establish the diagnostic usefulness of ultrasonography (US) and MR imaging in patients with rheumatoid arthritis (RA) suffering from prolonged pain in the ankle region, where plain radiography did not demonstrate any changes. MATERIAL AND METHODS: Seventeen patients were studied with 0.1 T MR imaging and with high-frequency US. Talocrural and subtalar joints (including talonavicular joints), and medial, lateral, and extensor tendons and their synovial sheaths were examined by MR and US. RESULTS: Abnormal findings were found by MR imaging and US in altogether 76% of the patients, by MR alone in 53%, and by US alone in 59%. In 41% of the patients, lesions were demonstrated only by one method. Talocrural and subtalar joints were the most often affected sites (41% each), followed by the peroneus tendon (23%). In the joints, the abnormal findings were interpreted as synovitis; in the tendon areas, mostly as tenosynovitis. MR and US were highly significantly concordant (p < 0.0001), but correlation with clinical features was poor. CONCLUSION: In patients with pain in the ankle region, US and MR imaging can contribute to the diagnosis and localization of the abnormality when the plain radiography is normal. Easily available and inexpensive US can be recommended as the first imaging method after plain radiography. Some divergence seems to exist between US and MR, and in complicated cases both methods are recommended.

User discipline in a personal computer-based filing of ultrasound records.

The discipline of entering ultrasound examination data in a personal computer file was studied over two periods. During the first period (19 weeks), the use of the computer was limited to one laboratory. During the second period (14 weeks), the computer was shared by three laboratories operating in nearby premises. During the study, 2857 (89%) of a total of 3209 ultrasound examinations performed were duly recorded in the data file. The frequency of failure to enter data was markedly higher during the second period (7-45%) than during the first period (5%) of the study. Overall, there was a highly significant (p less than 0.001) tendency to enter pathological findings at the expense of normal and non-diagnostic findings. The ease of access to the computer and the number of examinations recorded appear to determine user conscientiousness in filing data. Selection and omission of data impair the usefulness of the data log in research.

Effect of sampling technique on specimen size in fine needle aspiration biopsy.

The effect of the sampling technique in fine needle aspiration biopsy for cytology (FNAC) on the specimen size obtained was studied in vitro. The specimen size increased rapidly and linearly (P less than .001) with the number of needle passes, if the needle was angled between the passes into different directions in a fan-like fashion. However, if the needle was stroking repeatedly into the same channel, less and less tissue was detached per pass. The effect of the amplitude of needle passes (needle excursion) on the specimen weight was linear (P less than .001) after an initial plateau; when needle excursion was less than 3 to 4 mm, no tissue was detached. The specimen weight was significantly larger when a few passes with long needle excursions were used compared with a large number of passes with small needle excursions. Given an equal number of needle passes, the time interval (frequency) between these passes was less important. The sampling technique is important in determining the size of the specimen. The high incidences of unsatisfactory specimens reported and the wide variation in the accuracy rates of FNAC could be explained partly by differences in sampling techniques.

Effect of suction on specimen size in fine-needle aspiration biopsy.

High incidences of unsatisfactory specimens in fine-needle aspiration biopsy for cytology have been reported previously. Inappropriate aspiration techniques may account partly for this. In this study, the effect of suction on specimen size was studied in vitro using an automatic sampler. Bovine liver, testis, and pig's kidney were used as target tissues and biopsies were performed with 18-, 20- and 22-gauge needles. Specimen weight increased rapidly and linearly with suction force (P less than .001), regardless of the target tissue or needle diameter, when standard needle movement was applied. In the absence of needle movement, the suction force, rate of increase of suction, and duration of suction had no effect on the weight of the specimens. Needle movement alone, without suction, also produced meager specimens. Suction alone does not seem to tear fragments off target tissues. Nevertheless, in combination with needle movement, suction force plays an important role in the determination of specimen size.

A new method for investigating the sampling technique of fine needle aspiration biopsy.

An automatic sampler of fine needle aspiration biopsy for cytology (FNAC) is presented in order to study the technical performance of FNAC in vitro. The effects of the following sampling technique variables on specimen size and quality can be independently and quantitatively studied: suction force, duration and rate of increase of suction; count, frequency, amplitude and angle between the needle strokes; length, diameter, content and tip configuration of the needle; and target tissue. The efficacy of the sampler was compared with a manual method. It was demonstrated that the poor reproducibility of manual FNAC, combined with inaccuracy in following instructions regarding changes in sampling technique, render the manual system unsuitable for quantitative studies. The clumsiness of the manual system may be responsible for contradictory recommendations on how FNAC should be carried out. With the new in vitro sampler FNAC sampling can be studied under fully controlled conditions.

Fine-needle aspiration biopsy of liver hemangioma.

The results of 36 consecutive fine-needle aspiration biopsies of liver hemangiomas at two University Hospitals from the years 1981-1988 are described. The sizes of the lesions were 1 to 15 cm. Six patients had malignant disease, and liver metastasis was considered possible. In 2 cases the chief complaint was related to liver enlargement, and 28 patients had other abdominal symptoms. The aspiration was performed to confirm a suggested hemangioma in 18 and because of inconclusive findings at imaging in 18 cases. The aspirations were performed with sonographic guidance using 0.7 to 0.8 mm outer diameter needles. Cellular material from a hemangioma was obtained in 21 cases; only blood was aspirated in 5 cases. Hepatocytes were seen among abundant blood cells in 10, and some fibroblasts in 5 cases. One patient had significant bleeding that was treated with a transfusion of two units of blood. Nine patients were treated surgically, and histologic samples confirmed the diagnosis of hemangioma. None of the 27 non-operated patients showed progression of the liver lesion at 3 to 48 months follow-up. Fine-needle aspiration biopsy is helpful in the diagnosis of liver hemangioma. Confusion with malignancy is unlikely. Further experience will show the frequency of complications.

Sample size in fine needle aspiration biopsy.

The weights of biopsy specimens from bovine liver taken for fine needle aspiration cytology (FNAC) by three groups of physicians, were compared. The groups differed from each other in their extent or degree of experience in FNAC. When the physicians used their normal technique, the mean sample weight increased significantly with experience, from 4.6 mg in the least experienced group to 17.2 mg in the group with the longest experience. Thirty-six per cent of the samples taken by the group with the least experience were in the weight class 0-2 mg, whereas no such samples were encountered for the other groups. When all the physicians were advised to use the same, standard technique there were no statistically significant differences in mean sample weight between the groups or in the proportion of samples in class 0-2 mg. Sample weights correlated significantly (P less than 0.001) with cell counts. This study shows that differences in the technique of FNAC are responsible for differences in sample weights and cell counts, including the number of the acellular samples obtained. This could explain in some part the wide variation in the reported accuracy rates of FNAC.

Needle tip echogenicity. A study with real time ultrasound.

During ultrasound-controlled biopsy, the visualization of the needle tip is essential for its exact guidance. We constructed a testing device to simultaneously measure the needle tip echo (NTE) intensity of several needles. The following needle parameters were studied: the angle of incidence, the needle diameter, the needle tip bevel angle, and the orientation of the needle tip opening to the transducer. Measurements were made in A-mode using the highest amplitude peak of the NTE and in B-mode using the gray level histogram map from a fixed area around the NTE. There was a positive linear correlation between the intensity of the NTE and the angle of incidence in A-mode as well as B-mode. In A-mode a similar linearity was found between the NTE and the needle diameter, which in B-mode was exponential. However, the needle tip bevel angle did not affect the NTE. Rotating the needle around its longitudinal axis rendered the highest echo at an orientation of 180 degrees from the transducer in A-mode as well as B-mode.

Effervescent agents in the double contrast examination of the stomach.

The buffer capacities of the BaSO4, contrast media are poor. Yet the pH changes caused by effervescent agents or gastric contents are insignificant for mucosal adsorption. The increase of the viscosity and decrease of the density impair the results of the examination.