Levenberg-Marquardt Neural Network Algorithm for Degree of Arteriovenous Fistula Stenosis Classification Using a Dual Optical Photoplethysmography Sensor

This paper proposes a noninvasive dual optical photoplethysmography (PPG) sensor to classify the degree of arteriovenous fistula (AVF) stenosis in hemodialysis (HD) patients. Dual PPG measurement node (DPMN) becomes the primary tool in this work for detecting abnormal narrowing vessel simultaneously in multi-beds monitoring patients. The mean and variance of Rising Slope (RS) and Falling Slope (FS) values between before and after HD treatment was used as the major features to classify AVF stenosis. Multilayer perceptron neural networks (MLPN) training algorithms are implemented for this analysis, which are the Levenberg-Marquardt, Scaled Conjugate Gradient, and Resilient Back-propagation, to identify the degree of HD patient stenosis. Eleven patients were recruited with mean age of 77 ± 10.8 years for analysis. The experimental results indicated that the variance of RS in the HD hand between before and after treatment was significant difference statistically to stenosis (p < 0.05). Levenberg-Marquardt algorithm (LMA) was significantly outperforms the other training algorithm. The classification accuracy and precision reached 94.82% and 92.22% respectively, thus this technique has a potential contribution to the early identification of stenosis for a medical diagnostic support system.

TIA patients with higher ABCD3-I scores are prone to a higher incidence of intracranial stenosis, unstable carotid plaques and multiple-vessel involvement

The ABCD3-I criteria have proved to be effective for use in regular clinical practice to assist in transient ischemic attack (TIA) risk stratification and treatment. In this prospective study we aimed to explore the relationships between risk stratification and arterial stenosis location, carotid plaque morphology and vessel involvement in 90 TIA patients, stratifying risk by ABCD3-I scores. Clinical variables such as total cholesterol, triglyceride, low-density lipoprotein cholesterol, glycosylated hemoglobin, homocysteine and high-sensitive C-reactive protein levels were recorded. The endpoint was subsequent stroke at seven-day follow-up. Ninety patients were divided into three risk groups on the basis of their ABCD3-I scores. The results revealed that patients with higher ABCD3-I scores showed a higher occurrence of intracranial stenosis (P < 0.05), less organized carotid plaques (P < 0.05) and multiple-vessel involvement (P < 0.05).

Characterization of intracranial atherosclerotic stenosis using high-resolution MRI study--rationale and design

BACKGROUND

Intracranial atherosclerosis is a leading cause of stroke, but little is known about the composition of the intracranial atherosclerotic lesion and how intracranial plaque morphology is related to the risk of stroke. High-resolution magnetic resonance imaging (HR MRI) has been used in patients with extracranial carotid atherosclerosis as an in vivo tool to identify, with high-interrater agreement, histologically defined plaque components (i.e., intraplaque hemorrhage, fibrous cap, and lipid core), which have been shown to be predictors of recurrent stroke. With careful imaging the components of atherosclerotic plaque can be visualized in the intracranial arteries using HR MRI, but there are no reports of reproducibility or interrater reliability.

METHODS/STUDY DESIGN

The Characterization of intracranial atherosclerotic stenosis using high-resolution MRI (CHIASM) study is a single-center NIH-funded prospective observational study, to (1) demonstrate high -interrater agreement for identifying intracranial plaque components on HR MRI, (2) determine the frequency of these components in symptomatic versus asymptomatic plaques, and (3) estimate the 1-year rate of stroke in the territory of high-risk plaque components. CHIASM will recruit 90 patients with 50-99% intracranial atherosclerosis to undergo HRMRI of the intracranial artery plaque at enrollment and 1-year follow-up. Both symptomatic and asymptomatic subjects will be recruited.

CONCLUSION

Determination of good interrater reliability is an important first step in the development of HR MRI as a tool to predict risk in patients with intracranial atherosclerosis. This study will inform the design of future multicenter studies to determine the prevalence and prognosis of intracranial atherosclerotic plaque components. Such studies could lead to new understanding of the pathophysiological mechanisms of cerebral ischemia in patients with atherosclerotic intracranial stenosis, improvements in risk stratification, and potentially to new treatments of this common and serious disease.

[Some aspects of classification and treatment strategy of iatrogenic bile duct injury]

Iatrogenic bile duct injury continues to be an important clinical problem, resulting in serious morbidity, and occasional mortality, to patients. None of the classification system is universally accepted and worldwide used as each has its own limitation. This article reviews the various classification systems of bile duct injury. Traditionally, biliary injuries have been classified using the Bismuth's classification. This classification does not encompass the whole spectrum of injuries during laparoscopic cholecystectomy. Strasberg's classification made Bismuth's classification much more comprehensive by including various other types of extrahepatic bile duct injuries. Our own classification is simple enough, embraces the majority possible variants of bile duct injuries and convenient in clinical use.

Correlation of femoral artery flow velocity waveform with ipsilateral iliac artery stenoses assessed with magnetic resonance imaging

BACKGROUND

Magnetic resonance (MR) permits quantitative flow velocity measurements that could be used to detect changes in the curve profile downstream of a high-grade stenosis.

PURPOSE

To assess whether MR flow measurements can be used to detect iliac artery stenoses.

MATERIAL AND METHODS

Contrast-enhanced magnetic resonance angiography (MRA) and quantitative flow measurements in the lower aorta and proximal femoral arteries were performed in 29 patients with suspected iliac artery stenoses. Stenoses were graded into five degrees: 0%, 1-49%, 50-74%, 75-99%, and 100% diameter reduction. The femoral artery waveforms were evaluated qualitatively by two independent reviewers regarding peak systolic velocity (PSV), aortofemoral difference in time-to-peak (DeltaTTP), systolic acceleration (SA), curve-shape index (CSI), and the presence of an early diastolic flow reversal. The correlation between these parameters and the degree of stenosis was assessed.

RESULTS

A significant correlation with degree of stenosis was observed for the qualitative flow waveform evaluations, with a high degree of interobserver agreement (kappa = 0.84). A significant correlation was also found between degree of stenosis and PSV, DeltaTTP, SA, CSI, and presence of diastolic flow reversal. The flow velocity pattern, however, remained unchanged, both qualitatively and quantitatively, up to a stenosis degree of at least 75%.

CONCLUSION

Iliac artery stenoses cause femoral artery flow waveform changes that can be detected with MRI, but only at high-grade levels.

[Non transplant-related constrictive bronchiolitis in adults]

INTRODUCTION

The term bronchiolitis refers to inflammatory disorders of the bronchioles. Constrictive bronchiolitis is the type most frequently encountered.

STATE OF THE ART/PERSPECTIVES

The main clinical manifestations include the development of exertional dyspnoea and fixed airflow obstruction. Chest x-ray findings are usually unhelpful, but CT scanning may reveal a mosaic pattern on expiration. Peripheral micronodules are less frequently seen. The causes of constrictive bronchiolitis are numerous. The diagnosis may be clear from the clinical context when a causative event or predisposing condition can be identified (lung or bone marrow transplantation, toxic fume or gas inhalation, rheumatoid arthritis); in other conditions, a stepwise approach to the diagnosis is usually recommended in order to exclude other causes of subacute or chronic obstructive disease. Formal diagnosis requires histological examination of surgical lung biopsies. Despite corticosteroid administration, respiratory failure usually develops. Specific inhibitors of pro-inflammatory cytokines may offer a new and promising therapeutic approach.

CONCLUSIONS

If the clinical context or the radiology and clinical findings are not highly suggestive of a constrictive bronchiolitis, a surgical lung biopsy should be considered.

Intercondylar notch stenosis in degenerative arthritis of the knee

PURPOSE

To present a classification of intercondylar notch stenosis (IS) adjacent to the anterior cruciate ligament (ACL) in degenerative knee arthritis, to raise awareness of this disorder, to describe the arthroscopic findings, and to promote an organized approach to its treatment with favorable results.

TYPE OF STUDY

Case series.

METHODS

Of 362 arthroscopies in patients with gonarthrosis, we identified 122 knees in 96 patients (34%) with central knee pain and subjective instability without ACL laxity to determine the notch changes adjacent to the ACL. We followed a cohort of 69 knees in 64 patients, 47 female (73%) and 17 male (27%), excluding 53 knees in 32 patients for other symptomatic lesions, noncompliance with protocol, or loss to follow-up. The average patient age was 66 years (range, 53 to 78 years). Stenosis was classified as: type I, anterior; type II, lateral; type III, mixed; and type IV, massive. Diagnosis was determined by manipulation during arthroscopy to visualize impingement and was followed by notchplasty. Average follow-up was 26 months (range, 12 to 36 months).

RESULTS

Type III was most common, appearing in 48% of knees. Type I was found in 29%, type II in 20%, and type IV in 3% of knees. Preoperatively, central pain occurred in all patients, being moderate in 40 knees (58%) and severe in 26 knees (38%), with diminished strength and subjective instability in all cases; only 42 (61%) had knee extension loss. Flexion contracture resolved in 81% of cases; 90% had good to excellent pain relief and 74% excellent relief of subjective instability, without significant complications.

CONCLUSIONS

Intercondylar notch stenosis in the arthritic knee may be a cause of ACL damage, symptomatic instability, and loss of extension. A structured approach to diagnosis and treatment was beneficial in restoring more normal function for our patients and may prevent disease progression.

LEVEL OF EVIDENCE

Level IV.

Hilar benign biliary strictures: need for subclassification

BACKGROUND

A uniformly accepted classification allows an accurate comparison of results and formulation of a standardized treatment plan. Suggested herein is a subclassification of Bismuth type III post-cholecystectomy benign biliary strictures (BBS).

METHODS

Fifty-seven patients (41%) with Bismuth type III and eight patients (6%) with type IV BBS out of a total of 139 patients with BBS were analysed retrospectively. Strictures were subclassified as type IIIA where the confluence was healthy and type III B where the roof of the confluence was healthy and right and left ductal continuity was maintained, although the floor of the confluence was scarred.

RESULTS

Of 57 patients with type III BBS, 44 were subclassified as type IIIA and 13 as type IIIB. Statistically significant differences were observed in the mean operative blood loss (317 vs 635 mL, P = 0.004; 317 vs 606 mL, P = 0.006), blood transfused (0.8 vs 2.2 units, P = 0.0007; 0.8 vs 2.0 units, P = 0.0008), and duration of surgery (3.8 vs 5.1 h, P = 0.002; 3.8 vs 5.6 h; P = 0.0004) between type IIIA and IIIB, and between type IIIA and IV strictures, respectively. There were no differences in the operative parameters between type IIIB and IV strictures. There was no difference in the overall morbidity (18% vs 15% vs 25%) and septic complications among the three groups. At a mean follow up of 36.4 months, 87%, 91% and 100% of patients had excellent/good outcome in type IIIA, IIIB and IV, respectively.

CONCLUSIONS

Type III biliary strictures need to be subclassified, based on whether the floor of the confluence is healthy or scarred because it influences the degree of operative difficulty and morbidity. Type IIIB BBS behave like and should be classified with type IV strictures for uniformity of result evaluation.

Trigger digits: diagnosis and treatment

Stenosing tenosynovitis of the thumb and fingers is a very common problem seen by the primary-care physician, the orthopaedic surgeon, and the hand surgeon. Primary stenosing tenosynovitis is usually idiopathic and occurs more frequently in middle-aged women than in men, but can be seen even in infancy. Secondary stenosing tenosynovitis of the digits can occur in patients with rheumatoid arthritis, diabetes mellitus, gout, and other disease entities that cause connective tissue disorders. The diagnosis of triggering digits is generally not subtle and can be made on the basis of an adequate clinical examination. Classification according to the type of tenosynovitis and the time from onset of symptoms may be prognostically significant and may also affect the treatment outcome. As many as 85% of triggering fingers and thumbs can be treated successfully with corticosteroid injections and nonsteroidal anti-inflammatory drugs. Surgical release is generally indicated when nonoperative treatment fails. Percutaneous A1 pulley release can now be performed safely as an office procedure.

Management of nasopharyngeal stenosis after uvulopalatoplasty

OBJECTIVE

The objective of this study is to evaluate the management of nasopharyngeal stenosis (NPS) with the CO(2) laser and a customized nasopharyngeal obturator.

STUDY DESIGN

An 8-year retrospective study based at a tertiary care teaching hospital consisting of 18 patients with NPS after uvulopalatoplasty treated over an 8-year period with the CO(2) laser and a nasopharyngeal obturator. Patients with grade I stenosis were treated in the office and did not require a nasopharyngeal obturator. More severe cases (grades II and III) were treated in the operating room and required a nasopharyngeal obturator.

RESULTS

Eighteen patients with NPS, stages I to III, were treated with a CO(2) laser with or without a nasopharyngeal obturator with good results.

CONCLUSION

The repair of NPS with a CO(2) laser and a nasopharyngeal obturator in severe cases helps in restoring nasopharyngeal patency.

SIGNIFICANCE

This technique provided a reliable method of correcting postuvulopalatoplasty NPS.

Symptomatic improvement in dyspnea following tracheobronchial metallic stenting for malignant airway obstruction

PURPOSE

To investigate the value and limitation of Gianturco expandable metallic stenting for patients with dyspnea due to stenotic tracheobronchial lesions associated with malignancies.

MATERIAL AND METHODS

We treated 55 lesions of 44 patients with obstructing stenotic tracheobronchial lesions related to end-stage malignancies by Gianturco expandable metallic stents (EMSs).

RESULTS

In 42 of 44 patients, the dyspnea subjectively improved after the procedure (95.5%). An improvement over one grade of the Hugh-Jones classification was shown in 79.5% (35/44); in 80% (20 of 25 patients) with intraluminal tumor and in 78.9% (15 of 19 patients) with extrinsic compression. Seven of the 44 patients developed dyspnea related to re-stenosis of 10 lesions and 1 of these patients developed dyspnea related to re-re-stenosis during follow-up. The mean duration of survival was 4.3 months in patients who underwent stenting. No significant differences in survival rates and primary patency rates were seen in patients with extrinsic compression compared to patients with intraluminal tumors.

CONCLUSION

Gianturco EMS therapy was valuable in patients who suffered from dyspnea due to airway stenosis causing obstruction.

Treatment of intrahepatic biliary stricture associated with hepatolithiasis

Biliary stricture is a difficult complication in the management of hepatolithiasis. Resection of the hepatic segment containing biliary stricture(s) is ideal. Dilatation and stenting therapy with PTCSL in selective cases is a good adjuvant, sometimes alternative, therapy. We recommend a combination of multimodal treatment with a systemic approach to improve results. For recurrent or residual cases, PTCSL becomes the mainstay of treatment.

Current problems with intrahepatic bile duct stones in Japan--congenital biliary malformations as a cause

BACKGROUND/AIMS

In patients with primary intrahepatic bile duct stones, strictures of the biliary duct are often present, but the relationship between these strictures and the formation of the stones remains controversial. Intrahepatic bile duct carcinoma in association with intrahepatic bile duct stones has recently been reported. The present study attempted to ascertain whether bile stasis induced by congenital biliary strictures is the basis for the formation of stones and occurrence of carcinoma.

MATERIALS AND METHODS

We analyzed the location of strictures in 58 patients with strictures in the upper portion of the biliary tract including 38 patients with intrahepatic bile duct stones and 9 with intrahepatic bile duct carcinoma. The cell cycle of epithelial cells from the intrahepatic bile duct were analyzed with using proliferating cell nuclear antigen, which is a immunohistochemical staining method.

RESULTS

Fifty six of 58 patients had congenital cystic dilatation of the common bile duct (two infant type and 54 adult type). Thirty eight patients had intrahepatic bile duct stones proximal to the strictures at the hepatic hilum. The location of the strictures were classified into four types. Nine patients had intrahepatic bile duct carcinoma and eight of the 9 carcinomas coexisted with intrahepatic bile duct stones. In the nine patients with intrahepatic bile duct carcinoma, the expression of proliferating cellular nuclear antigen (PCNA) in the carcinoma and the normal bile duct epithelium adjacent to the carcinoma was higher than that of patients with hepatocellular carcinoma without anomaly of the biliary duct.

CONCLUSION

Considering the location of the strictures and clinical features, the strictures may have been formed congenitally. Furthermore, adult type cysts of the common bile duct with strictures in the upper portion of the biliary tract are thought to be the basis for the formation of primary intrahepatic bile duct stones. The most appropriate treatment for intrahepatic bile duct stones is thus suggested to be removal of the affected hepatic segment including the region of strictures, combined eventually with hepaticoenterostomy.

Surgical treatment of hilar strictures in hepatolithiasis

BACKGROUND/AIMS

The management of biliary strictures in hepatolithiasis, particularly at the hilus of the liver including the right and left hepatic bile ducts and their confluence, presents a challenge for surgeons because of their difficult access for surgical procedures and the life-threatening consequences, such as unrelenting cholangitis, recurrent biliary calculi, liver abscess and septicemia they can cause. This study analyzed the response of a group of patients with hilar strictures undergoing different surgical operations to assess methods dealing with this condition.

PATIENTS AND METHODS

A total of 545 patients with hepatolithiasis were admitted to our hospital. Among them, 256 patients were found to have an association of high bile duct strictures. These were classified into three types based on the sites of the stricture, and operated on with different combined surgical procedures in accordance with the type of the strictures. After the operation, further assessment was made during a follow-up period of between 12 months to 6 years.

RESULTS

Postoperative morbidity and mortality were 15.7% (40/256) and 1.2% (3/256), respectively. Before discharge from the hospital, all patients underwent imaging investigation, and the retained stone rate was 20.3% (53/256). Of the 70% of patients (179/256) who were available for further assessment, 85% had good treatment results, were asymptomatic and required no medical treatment. A few patients got a poor result when symptoms of cholangitis occurred several times a year and required hospitalization.

CONCLUSIONS

Successful treatment of hilar strictures in hepatolithiasis depends on the correct localization of the strictures, and complete exposure of the biliary tract proximal to strictures as well as the appropriate selection of the surgical procedures.

Morphology of intrahepatic duct in surgical treatment of hepatolithiasis

BACKGROUND/AIMS

Surgery is the usual treatment for hepatolithiasis. However, the method of choice is based on intrahepatic duct morphology.

MATERIAL AND METHODS

Six hundred sixty-two patients with hepatolithiasis were operated on in the period between 1980-1994. Hepatolithiasis was clinically classified into primary (75.8%) and secondary (24.2%) types.

RESULTS

Patients treated between 1990-1994 (35.9%), liver resection was performed in 71 patients (69 of left and 2 of the right liver). However, liver resection was chosen only in 6.7% (11/163) during the 1970s. Candidacy for liver resection increased recently due to the increase in primary type. According to the morphology of intrahepatic ducts, the location of stricture was classified into: Central type (n = 59, 30%), Segmental type (n = 101, 51%), and Subsegmental type (n = 21, 10.6%), and unclassified (n = 17, 8.4%). Liver resection was recommended for patients of segmental or subsegmental type. Choledocho-lithotomy with T-tube drainage was indicated in two third of the patients with hepatolithiasis. However, the incidence of post-operative retained stones was very high, and post-operative choledochoscopic lithotripsy was used to treat these post-operative problems easily. The mortality of this disease was 1% (2/198) in the 1990s compared with that of 4.1% (19/464) in 1980s and 10.1% (15/148) in 1970s.

CONCLUSION

We strongly recommend that liver resection for patients with adequate indications will have good results. In addition, one should pay attention to the abnormal pattern of intrahepatic ducts that are commonly found in patients with hepatolithiasis during liver resection. Liver resection is an ideal surgical method for the eradication of diseased lesions and to prevent malignant changes from bile duct with stones. Concise information concerning the anatomic structure was found to be important in determining post-operative results in the management of hepatolithiasis.

Chiari I malformation: classification and management

Considerable debate exists about which surgical options are best for the management of the Chiari I malformation. We present a classification system for the Chiari I malformation that improves the prediction of outcome and guides the selection of surgical treatment. Twenty-seven adult patients with Chiari I malformations were grouped on the basis of the presence of signs and symptoms of brain stem compression, syringomyelia, or both. To objectively assess changes in clinical status postoperatively, a scale was developed to quantify the signs and symptoms, which were statistically analyzed by the paired t test. Five patients were asymptomatic and underwent no treatment. Ten patients had symptoms of brain stem compression without associated syringomyelia and underwent brain stem decompression, including anterior decompression in one patient with basilar invagination; all 10 patients had significant improvement at 4-year mean follow-up visits (P < 0.0001). In 12 patients with syringomyelia, 5 were symptomatic from syringomyelia only, 6 were symptomatic from both brain stem compression and syringomyelia, and 1 was symptomatic from brain stem compression only. The median length of symptoms before presentation was longer for patients with syringomyelia than for patients without (2 yr versus 9 mo; P < 0.025); the mean follow-up was 4 years. Surgical procedures included posterior brain stem decompression in 12 patients, plugging of the obex in 7, and placement of syringosubarachnoid shunts in 7, a syringopleural shunt in 1, and fourth ventricular stents in 2. In the 12 patients with syringomyelia, symptoms from brain stem compression dramatically improved with surgical decompression (P < 0.025), whereas symptoms from syringomyelia less dramatically improved or stabilized. The slight improvement or stabilization of syrinx symptoms represents a successful result, given the documented progressive nature of syringomyelia in this group. We conclude that surgical treatment for the Chiari I malformation can stabilize or slightly improve the symptoms attributed to syringomyelia and dramatically relieve the symptoms of brain stem compression. Furthermore, early diagnosis and treatment are critical in obtaining the best outcome for the patient.

Contribution of transcranial color-coded real-time sonography to the etiopathogenetic classification of middle cerebral artery stenosis

Transcranial color-coded real-time sonography (TCCS) and cranial computed tomography were applied to patients with middle cerebral artery (MCA) stenosis to evaluate whether these techniques may disclose additional aspects of the pathophysiology of the stenotic lesion. In 15 patients with MCA stenosis identified by transcranial Doppler sonography, the echogenicity of the stenotic segment was estimated subjectively by TCCS. The density of the stenotic segment, prior to being detected by TCCS, was quantified by computed tomography. In 5 of the 15 patients, transcranial image-directed Doppler sonography identified a hyperechogenic lesion in association with the stenotic vascular segment; computed tomography demonstrated a "dense" artery (Hounsfield units [HU] > 120) in the corresponding vascular segment. In 10 patients the echogenicity of the stenotic segment was found to be normal, with a computed tomography density of < 100 HU in the corresponding segment. Hyperechogenic and hyperdense stenotic vascular segments in TCCS and computed tomography, respectively, may indicate an arteriosclerotic vascular lesion with calcium deposits. Normal echogenicity and normal to slightly elevated computed tomography-density of a stenotic vascular segment may suggest the presence of a thrombotic/embolic lesion.

Dynamics of the sounds caused by partially occluded femoral arteries in dogs

Previous studies have indicated that partially occluded arteries produce sounds due to turbulence. If these sounds from the coronary arteries could be detected externally, they would provide a simple approach to the detection of coronary artery disease. To confirm the hypothesis that coronary stenosis produces detectable acoustic correlates, sounds caused by a controlled occlusion of the femoral artery of dogs were detected and analyzed using both the fast Fourier transform (FFT) and the autoregressive (AR) methods. The femoral artery was chosen, since its size and flow approximate those of coronary arteries in humans. The poles of the AR spectra and the power ratios of different sections of the FFT and AR spectra were used to differentiate the degree of the stenosis. The results showed that high frequency acoustical power between 200 and 800 Hz is associated with the turbulence produced by the partially occluded femoral arteries of the dogs. Using the AR method, high acoustic power above 200 Hz increased when the degree of the occlusions increased. The poles and power ratios of the AR spectra differed according to the degree of stenosis. However, the high frequency acoustical power above 200 Hz did not increase above the 85% occlusion.

Accuracy and reproducibility of duplex ultrasonography in grading femoropopliteal stenoses

PURPOSE

The aim of this study was to determine the accuracy of Doppler waveform characteristics in grading femoropopliteal stenoses and to determine the interobserver and intraobserver reproducibility of measuring the same waveform characteristics.

METHODS

Thirty patients with isolated areas of stenosis found by arteriography were evaluated by color duplex sonography. Each patient underwent scanning by two observers on two separate occasions. Each observer was blind to the other's results. Doppler spectra were recorded in areas where color change suggested the highest velocity and also at the nearest normal proximal area. Peak systolic velocity, spectral broadening, and waveform configuration were measured at each site.

RESULTS

An increase in peak systolic velocity of more than 200% accurately predicted a 50% or greater reduction in luminal diameter on angiography (70% sensitivity, 96% specificity). The presence of spectral broadening and an abnormal waveform shape were found to correlate poorly with the degree of stenosis. Analysis of variance showed no significant difference between observers in velocity measurements (p = 0.78).

CONCLUSIONS

We conclude that although stenoses of greater than 50% can be distinguished from minor stenoses, more precise definition of the degree of narrowing is unlikely. The good repeatability of the velocity ratio makes it an excellent tool for monitoring major changes in the progression of disease.

Clinical classification of perianal Crohn's disease

Assessment of the efficacy of therapeutic approaches to anal lesions of Crohn's disease is frustrated by the lack of precise definition of its various manifestations. A classification that is clinical and based on anatomic and pathologic aspects is presented; it has been derived from a 20-year prospective study of anal Crohn's disease in Cardiff. Conceptually, the classification is analogous to the TNM system for cancer. The main classification (U.F.S.) defines the presence of Ulceration, Fistula/abscess, and Stricture, qualified by numeric values reflecting severity (0 = not present, 1 = limited clinical impact, and 2 = severe). A subsidiary classification (A.P.D.) defines Associated conditions, Proximal intestinal involvement, and Disease activity. In addition, the classification may be used in a detailed form for research or comparative purposes or in a simple form defining only the dominant lesions for routine clinical use. General use of the classification would make it possible to compare in detail incidence, management, and results of treatment in different centers.

[New criteria for the classification of the popliteal artery entrapment syndrome. Our experience with 14 extremities]

Authors explain their experiences with eight patients (14 affected limbs) with a popliteal artery entrapment syndrome. Classification, diagnosis and treatment were reviewed. Six limbs, with any malformation and presenting as a unique sign an important hypertrophy of their intern gastrocnemius muscle, couldn't be classified. As a result, a new classification of this pathology is presented being based on the anatomical and arteriographic aspects as well as oh the surgical indication. The important correlation between anomaly, physical complexion typus athletic and sports is noted.

Technique for precise, graded arterial stenosis and occlusion

A variable mechanical occluder has been designed which, by means of a micrometer, permits graded stenosis of an artery in precise, reproducible increments. The design also allows transient, complete occlusion of the artery to establish zero flow without alteration of the level of stenosis established prior to the zeroing procedure. The device has been used to partially block the reactive hyperemic response following coronary and femoral artery occlusion, but is readily adaptable to vessels of other size by means of an interchangeable occluder subassembly.