Imaging and Timing Performance of 1cm × 1cm Position-sensitive Solid-state Photomultiplier.

We have designed and built a large-area 1cm × 1cm position-sensitive solid-state photomultiplier (PS-SSPM) for use in detector design for medical imaging applications. Our new large-area PS-SSPM concept implements resistive network between the micro-pixels, which are photodiodes operated in Geiger mode, called Geiger Photodiodes (GPDs), to provide continuous position sensitivity. Here we present imaging and timing performance of the large-area PS-SSPM for different temperatures and operating biases to find the optimum operating parameters for the device in imaging applications. A detector module was built by coupling a polished 8×8 LYSO array, with 1×1×20 mm3 elements, to a 1×1 cm2 PS-SSPM. Flood images recorded at room temperature show good crystal separation as all 64 elements were separated from each other. Cooling the device at 10 °C showed significant improvement. The device optimum bias voltage was ~4.5V over breakdown voltage. The coincidence timing resolution was improved significantly by increasing the operating bias, as well as by lowering the temperature to 0 °C. Results show excellent imaging performance and good timing response with a large-area PS-SSPM device.

[Clinical guidelines for the screening and the diagnosis of autism and pervasive developmental disorders]. / Recommandations pour la pratique clinique du dépistage et du diagnostic de l'autisme et des troubles envahissants du développement.

UNLABELLED: Autism is the best defined category among PDD. Its high prevalence, its onset in very young children and its persistence in adulthood arise many questions about early screening and early diagnosis. The aim of the study was to identify professional best practices about screening and diagnosis of autism in order to propose clinical guidelines and actions for the future. Scientific experts and parents take part to this procedure. Literature and previous guidelines were analyzed, experts in various fields were interviewed, a national study about the medical practices of the diagnosis of autism was made and questionnaires were send to 1600 psychiatrists and pediatricians. Guidelines built around 2 levels were proposed about screening and diagnosis. CONCLUSION: Diagnosis needs a multidisciplinary approach, validated instruments and more communication between professionals and parents. Finally one of the more important aims of the diagnosis of autism is to facilitate intervention program.

Physical therapy in Parkinson's disease: an open long-term rehabilitation trial.

The aim of this study was to evaluate the effects of prolonged physical therapy on disability in patients with Parkinson's disease. The study was designed as an open long-term trial over 20 weeks. Twenty slightly to moderately affected parkinsonian patients were included (Hoehn & Yahr stages: 1.5-3). A comprehensive rehabilitation program was applied three times a week in all patients. Pharmacological treatment was kept stable. Evaluations were performed at baseline, at the end of treatment and after 3 months. Following physical rehabilitation, there was a significant improvement in UPDRS (ADL and motor sections) scores, Self-assessment Parkinson's disease Disability Scale, Ten-Meter Walk test and Zung scale for depression. At 3-month follow-up clinical improvements were largely maintained. A sustained improvement of motor skills in PD patients can be achieved with a long-term comprehensive rehabilitation program.

N(N)-nicotinic blockade as an acute human model of autonomic failure.

Pure autonomic failure has been conceptualized as deficient sympathetic and parasympathetic innervation. Several recent observations in chronic autonomic failure, however, cannot be explained simply by loss of autonomic innervation, at least according to our current understanding. To simulate acute autonomic failure, we blocked N(N)-nicotinic receptors with intravenous trimethaphan (6+/-0.4 mg/min) in 7 healthy subjects (4 men, 3 women, aged 32+/-3 years, 68+/-4 kg, 171+/-5 cm). N(N)-Nicotinic receptor blockade resulted in near-complete interruption of sympathetic and parasympathetic efferents as indicated by a battery of autonomic function tests. With trimethaphan, small postural changes from the horizontal were associated with significant blood pressure changes without compensatory changes in heart rate. Gastrointestinal motility, pupillary function, saliva production, and tearing were profoundly suppressed with trimethaphan. Plasma norepinephrine level decreased from 1.1+/-0.12 nmol/L (180+/-20 pg/mL) at baseline to 0.23+/-0.05 nmol/L (39+/-8 pg/mL) with trimethaphan (P<.001). There was a more than 16-fold increase in plasma vasopressin (P<.01) and no change in plasma renin activity. We conclude that blockade of N(N)-cholinergic receptors is useful to simulate the hemodynamic alterations of acute autonomic failure in humans. The loss of function with acute N(N)-cholinergic blockade is more complete than in most cases of chronic autonomic failure. This difference may be exploited to elucidate the contributions of acute denervation and chronic adaptation to the pathophysiology of autonomic failure. N(N)-Cholinergic blockade may also be applied to study human cardiovascular physiology and pharmacology in the absence of confounding baroreflexes.

Quantitative measurement of lead in paint by XRF analysis without manual substrate correction.

X-ray fluorescence analysis has been used for measurement of lead in paint for more than a decade. The early systems provided a nondestructive alternative technology to laboratory-based technologies, but were somewhat time consuming and often led to inconclusive results. The procedure required manual substrate correction, multiple measurements, operator's discretion in validating a measurement due to interfering elements and laboratory analysis of inconclusive samples. A new instrument, the RMD LPA-1 system, has been developed based on X-ray fluorescence technology that addresses all of the drawbacks to the older systems. This new system uses a carefully designed and controlled geometry and modern microprocessor technology to automatically provide a rapid quantitative measurement of lead in paint with a 95% confidence level. The improved precision and accuracy achieved with this system are due to geometric enhancements and a mathematical approach which incorporates corrections for both random and systematic errors such as matrix effects and Compton scatter. This technology has been incorporated in a hand-held X-ray fluorescence lead paint analyzer system. A key design philosophy for this system was to maintain a very narrow, task-specific focus, the system was not designed to be an all purpose XRF analyzer, rather it is optimized to meet regulatory requirements of lead paint testing in the most efficient manner. The development of the LPA-1 system is an example of what can be accomplished by listening to the needs and desires of the users, rethinking the design of an existing technique and incorporating modern microprocessor technology.

Cytological vs microhistological diagnosis of hepatocellular carcinoma: comparative accuracies in the same fine-needle biopsy specimen.

There is still debate over the relative merits of cytology and histology in diagnosing hepatocellular carcinoma in cirrhotic livers. Previous comparisons of the diagnostic accuracies of these two methods may have been biased by sampling errors due to multiple punctures. We compared the diagnostic accuracies of cytology and microhistology using tissue and cells from the same point in liver nodules subsequently proved to be hepatocellular carcinoma. A single ultrasound-guided liver-nodule biopsy was obtained with a 20- to 21-G cutting needle from 131 cirrhotic patients. The solid portion of samples was used for microhistology; the remainder was subjected to smear cytology. The results of each type of examination were expressed as true positive, nonspecific malignancy, false negative, or inadequate for diagnosis. No false-positive diagnoses were made in 13 benign lesions. In 118 HCC nodules (particularly those <30 mm in diameter), cytology provided a significantly higher percentage of correct diagnoses (85.6%) that was only slightly inferior to that based on results of both studies (89.8%). The single-biopsy technique generally provides adequate tissue for histology and cytology specimens with a high cellularity. It reduces both the cost and the risks of fine-needle biopsy diagnosis of hepatocellular carcinoma.

Percutaneous biopsy in diffuse liver disease: increasing diagnostic yield and decreasing complication rate by routine ultrasound assessment of puncture site.

OBJECTIVE: To evaluate the usefulness of routine ultrasound assessment of puncture site before performing percutaneous biopsy in diffuse liver disease. Seven hundred fifty-three consecutive patients were studied retrospectively. METHODS: Serial scanning of the last intercostal spaces allowed us to establish the most suitable access to the thicker liver parenchyma (assessing the most favorable angulation of the needle too), avoiding the puncture of adjacent organs; no more than 1 min was necessary for such a determination. RESULTS: In 99.4% of patients, a definitive or indicative pathological diagnosis of chronic liver disease was obtained. Only one hemorrhagic complication (0.13%) occurred, requiring no surgical treatment or blood transfusion. Three cases of vasovagal reaction occurred (0.40%): two of these recovered spontaneously, while the other one needed i.v. administration of atropine. Mortality was 0 in our series. CONCLUSIONS: Routine ultrasound of the puncture site is a quick method of assessment, allowing one to increase the diagnostic yield of percutaneous liver biopsy and to maintain low complication rates for such a procedure.

Free-hand technique with ordinary antisepsis in abdominal US-guided fine-needle punctures: three-year experience.

PURPOSE: To evaluate the adequacy of ordinary antisepsis in ultrasound (US)-guided free-hand fine-needle puncture. MATERIALS AND METHODS: Diagnostic and therapeutic procedures (n = 573) were performed in 456 patients. No puncture attachments, sterile gloves, or drapes or covers were used. Before each procedure the transducer was cleaned with a solution of water and 70% alcohol. No needles were contaminated. Patients were monitored for 5 days to exclude sepsis. Subsequently, the patients underwent follow-up blood and laboratory testing, including testing for for hepatitis B and C markers and human immunodeficiency virus antibodies, every 3 months for 6 months. The operators underwent the same follow-up for the first 6 months and for an additional 6 months. RESULTS: No patient or operator presented with fever or sepsis or with negative viral or hepatitis markers that became positive during follow-up. CONCLUSION: Use of this free-hand US-guided technique with ordinary antisepsis is safe for patients and operators, and it allows savings in time and the cost of materials.

Incidence of gallstones in a population of patients with cirrhosis.

One hundred and sixty-five patients with cirrhosis were prospectively investigated, by regular ultrasonographic follow up, to assess the incidence of gallstones. The mean length of follow up was 33 months (range 12 to 108). Cholelithiasis was diagnosed in 31 patients (18.8%), with a cumulative incidence over 84 months of 38.3% (4.7% yearly incidence). The risk of gallstones was similar in males (38%) and females (38.3%), although the final cumulative incidence was reached at 72 months in males. The percentage of patients with new stones was higher in alcoholic cirrhosis (28.9%) (with a cumulative incidence of 48.8% at 84 months) and lower in hepatitis-related cirrhosis (1.9%) (only one new case at 96 months of follow up) (p < 0.001). The cumulative incidence of gallstones in the Child's C group reached 49.3% at 48 months versus 24% in Child's B and 6.4% in Child's A (p < 0.0001). At multivariate analysis, Child's C and alcoholic cirrhosis were shown to be the independent variables significantly associated with a high risk of development of cholelithiasis. This study confirms that cirrhosis represents a high risk factor for gallstones. The risk is greater for alcoholic cirrhosis and increases with the severity of the disease.

Ultrasound-guided fine-needle biopsy of hepatocellular carcinoma: comparison between smear cytology and microhistology.

OBJECTIVES: The aims of this study were to evaluate the typing accuracy of smear cytology and microhistology and of their association in the diagnosis of hepatocellular carcinoma arising in liver cirrhosis, and to analyze the usefulness of smear cytology in the diagnosis of well-differentiated neoplasms. METHODS: One hundred sixty patients with hepatocellular carcinoma underwent an ultrasound-guided fine-needle biopsy, providing material for cytological and histological study. In 73 patients, a double biopsy with noncutting and cutting needles was performed (double-needle group), whereas in the remaining 87, a single biopsy with cutting needle was carried out (single-needle group). RESULTS: In the whole population examined, smear cytology, microhistology, and their association, provided the diagnosis of hepatocellular carcinoma in 128 (80%), 98 (61%), and 144 (90%) cases, respectively. The double-needle and the single-needle groups did not differ significantly as to typing accuracy. Smear cytology correctly diagnosed 54 of 64 neoplasms classified histologically as well-differentiated. CONCLUSIONS: Our results show that both smear cytology and microhistology should be applied immediately, when diagnosing hepatocellular carcinoma arising in liver cirrhosis, and that smear cytology is effective in the diagnosis of well-differentiated neoplasms.

Cruveilhier-Baumgarten syndrome: an efficient spontaneous portosystemic collateral preventing oesophageal varices bleeding.

The protective role of large spontaneous portosystemic shunts in oesophageal varices bleeding due to portal hypertension in liver cirrhosis is still debated. A series of 20 consecutive patients with haemodynamically efficient collaterals involving the para-umbilical-epigastric venous route (evaluated by Echo-Doppler flowmetry) is reported. All patients presented absent or mild oesophageal varices at endoscopy. During a mean follow-up period of 23.5 months, no patient developed large varices or experienced variceal bleeding. Hepatic encephalopathy was present in 35% of patients. Haemodynamically efficient spontaneous portosystemic shunts may protect cirrhotic patients from the risk of oesophageal varices forming and bleeding. The diversion of large amounts of blood from portal to systemic circulation correlates with the higher trend of hepatic encephalopathy in these patients.

Fine-needle liver biopsy in patients with severely impaired coagulation.

Severe coagulation defects, as reflected by platelet count and prothrombin time, have always been considered a contraindication to needle biopsy of the liver, but there are very limited data on the actual rate of bleeding in patients with such severe alterations and none whatsoever on the bleeding risk associated with newer, fine-gauge needles that produce less trauma to the liver tissue. In addition, there has never been any evidence that platelet count and/or prothrombin time are the most sensitive indices of bleeding risk. This retrospective study of 85 patients, with platelet counts less than 50,000/mm3 and/or prothrombin times less than 50% of controls, subjected to ultrasound-guided fine-needle liver punctures for diagnostic or therapeutic (percutaneous ethanol injection) purposes showed no bleeding episodes after any of the 229 punctures performed. No type of replacement therapy was administered to correct clotting defects prior to the procedure. Correct pathologic diagnoses were obtained in 81.2% of all patients. Ultrasound-guided fine needle puncture appears to be safer than currently believed in patients with severe clotting defects and deserves further evaluation as an alternative to surgical procedures to diagnose and treat liver lesions, even when severe coagulation impairment is present.

Focal ultrasound lesions in cirrhotic liver diagnosed as regenerative nodules by biopsy. A morphometric analysis.

Ten cirrhotic patients with ultrasonically discernible focal liver masses underwent fine cutting needle biopsy. Specimens were obtained from the focal lesions under ultrasound guidance and histologically diagnosed as regenerative nodules. An image analyzer was then used to determine the cytoplasmic area, nuclear area, and nuclear/cytoplasmic ratio for 100 randomly selected cells from each specimen. Data were then compared with data for specimens of normal liver tissue and data from patients with alcoholic or posthepatic cirrhosis or well-differentiated hepatocellular carcinoma (HCC). The morphometric parameters for the group of regenerative nodule specimens fell within an intermediate range between those for HCC and the nondysplastic samples, strongly suggesting a preneoplastic nature. Nine of the 10 regenerative lesions showed liver cell dysplasia, and 3 of these patients developed HCC during follow-up. Ultrasonically discernible focal masses in a cirrhotic liver should be considered preneoplastic, if not neoplastic lesions and treated aggressively to prevent their progression to outright malignancy.

Nodular lesions of the liver in multiple myeloma: a role for cytoadhesion molecules?

Two patients with multiple myeloma and in vivo macroscopic nodular lesions of the liver are presented. The clinical aspects of this very unusual condition are briefly reviewed. In particular, the expression on neoplastic plasma cells of the cytoadhesion molecules CD56 and CD11a, which are involved in the cellular process of recirculation and homing, suggests a possible role for such markers in this atypical localization of the disease.

[Chronic inflammatory bowel diseases in childhood. Case contribution and critical considerations]. / Le malattie infiammatorie croniche intestinali in età pediatrica. Contributo casistico e considerazioni critiche.

The term "inflammatory bowel disease" describes 2 major categories of chronic disease: Crohn's disease and ulcerative colitis. Non specific chronic colitis and allergic colitis in childhood can usually be distinguished by clinical and histopathologic criteria. This study regards a retrospective analysis of 23 patients suffering from chronic inflammatory bowel disease. Clinical manifestations began between 4 and 18 years of age. The Authors report remarkable frequency in pediatric age and common diagnostic delay, especially in Crohn's disease. The possibility of extraintestinal symptoms (erythema nodosum, arthritis, iridocyclitis) is also showed. Moreover they analyse present diagnostic proceedings: in childhood the employ of 99 mTc-HmPAO-labelled granulocytes is a new and non invasive test useful in the follow-up of the patients. In the treatment corticosteroids and sulfasalazine are used in various combinations associated with general supportive measures. Finally the Authors confirm that chronic inflammatory bowel disease may cause, especially in childhood, remarkable involvement on the growth and several psychological disorders.

Hypoechoic lesions in the 'bright liver': a reliable indicator of fatty change. A prospective study.

The accuracy of ultrasonographic diagnosis of hypoechoic focal fatty change in the 'bright liver' was evaluated in 40 lesions found in 35 patients followed up for a mean period of 37.8 months. Patients with ultrasound and laboratory findings suggesting liver cirrhosis were excluded from the study. All patients underwent a blind liver biopsy in order to verify the diagnosis of diffuse disease suggested by the finding of 'bright liver'. No guided biopsy was performed on the focal lesions in order to establish the accuracy of ultrasound alone in recognizing focal fatty change. Clinical, haematologic and echographic follow-up confirmed the diagnosis in all cases. All histological specimens revealed liver steatosis, indicating a 100% sensitivity of ultrasonography in identifying non-cirrhotic fatty liver with an accompanying focal change. Increased echogenicity and hypoechoic focal changes are reliable indicators of fatty infiltration, making ultrasonography an acceptable, non-invasive method for the diagnosis of liver steatosis.

Gallbladder emptying in patients with primary achalasia.

Being more evident that primary achalasia is not confined to the esophagus and that it may involve other organs in the digestive tract, gallbladder emptying was ultrasonographically evaluated in 10 patients affected with primary achalasia and in 10 controls. An intravenous cerulein infusion was used to induce gallbladder contraction. Eight out of 10 achalasic patients had a lower gallbladder emptying, and 6 out of 10 had a markedly delayed gallbladder emptying compared with the controls. Achalasic patients, taken as a whole, showed a significantly lower and delayed mean gallbladder emptying when compared with the controls. Such a finding confirms the possible extra-esophageal extension of primary achalasia. In this study, the hypothesis of impaired cholinergic gallbladder innervation in primary achalasia is discussed.

Hypoechoic lesions in fatty liver. Quantitative study by histomorphometry.

Ten patients with fatty liver changes were subjected to liver biopsies. In seven, ultrasonography showed focal hypoechogenicity within a "bright" liver, generally interpreted as focal sparing. Three patients had hyperechoic areas surrounded by "normal" parenchyma usually felt to represent local fat accumulation without diffuse involvement. Morphometric analysis was used to determine the total area occupied by fat (area density) and the number of lipid droplets (numerical density) per microscopic field in lesional and perilesional specimens. Compared with respective perilesional values, hypoechoic lesional numerical densities were significantly lower in 6 of 7 patients; the three hyperechoic samples had significantly higher values. In most cases, lesional and perilesional area densities were not significantly different. These hypoechoic focal lesions are believed to be merely areas in which a similar quantity of fat is contained in fewer droplets, and focal hyperechogenicity is believed to result from a larger number of fat-filled vacuoles with respect to that of the surrounding parenchyma. Variation in the number of solid-liquid interfaces causes the ultrasonic contrast between these lesions and the similarity fatty liver parenchyma surrounding them.

Accurate automatic exposure controller for mammography: design and performance.

An automatic exposure controller has been designed that controls the optical film density for film, screen, and radiographic techniques typically used in mammography to within 0.05 over a range of 1.3-6.7-cm thickness of Lucite. This degree of accuracy is better than that reported for presently available controllers. The detector system consists of four cadmium telluride detectors and involves the use of a control algorithm to read the detectors and turn off the mammography unit at the correct time. This algorithm is implemented by a microprocessor, which also provides the means for a convenient calibration.