Dimitrios G. Spigos

Ultrasonography of Blood During Stasis and Coagulation

A series of in vitro and animal experiments were performed to determine ultrasonic features of blood during stasis and coagulation. Liquid whole blood became echogenic within a few seconds to 3 minutes following the onset of stasis. This occurred in citrated human blood allowed to stand and in occluded segments of vena cava and aorta of dogs. Mechanical agitation of the blood in stasis caused a disappearance of echoes. This echogenicity occurred with gray-scale and real-time ultrasonography using 7.5-mHz transducers, but was not observed with 3.5-mHz transducer used in real-time scanning. Whole blood clot was echogenic both with 7.5- and 3.5-mHz scanning. Fibrin clot was sonolucent. Echogenicity with stasis did not occur with plasma, serum, or packed erythrocytes. The development of echogenicity required the presence of fibrinogen or its products plus erythrocytes. The echogenicity of blood during stasis detectable by high-frequency ultrasonography probably was related to physical layering of blood products. The disappearance of reflective echoes following agitation suggested that the layering could be readily disrupted.

Effect of Plasma Proteins and Temperature on Echogenicity of Blood

An explanation is proposed for the echogenicity to ultrasound scanning at 5 mHz and above of unclotted blood under conditions of stasis. In vitro experiments using blood from normal subjects and from patients with myeloma revealed that: 1) lysis of red cells prevented echogenicity, 2) echogenicity increased with increasing hematocrit, fibrinogen and other macromolecules, and temperature, and 3) blood from myeloma patients showed increased echogenicity and rouleau formation, a form of aggregation seen on peripheral smears. From these experiments it was concluded that red cell aggregation is a major cause of echogenicity of unclotted blood, requiring both intact red cells and conditions which are known to enhance red cell aggregation, such as the presence of macromolecules and increased temperature.

High resolution proton magnetic resonance spectroscopy of human brain and liver

Water-suppressed and slice-selective proton spectra of live human brain exhibited several resonances that were tentatively assigned to metabolites such as N-acetylaspartate, glutamate, phosphocreatine and creatine, choline derivatives, and taurine. In the liver spectrum of a healthy volunteer, the major resonance was tentatively assigned to a fatty acyl methylene and the minor resonances to protons in carnitine, taurine, glutamate, and glutamine. In the spectrum of a cancerous liver, resonances in addition to those present in the normal liver were seen. Protein degradation in the liver with cancer was indicated by resonances from urea and from the ring protons in tryptophan, tyrosine, and phenylalanine. Furthermore, increased nucleic acid synthesis was indicated by resonances from nucleotide protons.

Adventitial cyst of the popliteal artery: CT-guided percutaneous aspiration.

Adventitial cystic disease of the popliteal artery is a rare condition of uncertain etiology in which a mucinous cyst forms in the wall of the popliteal artery, obstructing the lumen and producing symptoms of intermittent claudication. We report a case in which percutaneous cyst puncture guided by CT resulted in emptying of the cyst contents, with restoration of luminal patency and a normal pulse.

Ultrasonic imaging during biliary and pancreatic surgery

Real-time ultrasound scanning was used during operations on the biliary tract and pancreas. The principal application in biliary surgery was to evaluate the common bile duct for presence of calculi. Our initial experience indicates that operative ultrasonography compares favorably with operative cholangiography. In pancreatic operations, ultrasound has been helpful in the management of pseudocysts and chronic pancreatitis. For pseudocysts, ultrasonography has indicated cyst wall thickness and the presence of adjacent anatomic structures. Ultrasound has distinguished the fluid loculations of the pseudocyst from swelling due to inflammatory edema. In surgery for chronic pancreatitis, ultrasonography has revealed the size and location of pancreatic ducts. This information has been useful in helping select sites for internal drainage of pseudocysts and in chronic pancreatitis with ductal dilatation. Operative ultrasonography is a relatively simple procedure which has the potential for providing the surgeon with early information and decreasing the need for dissection and radiographic imaging.

Atypical transmural thoracic lipoma: CT diagnosis.

Two cases of transmural thoracic lipomas demonstrate a pattern of rib involvement that has not been previously reported. The lipomas presented with an otherwise characteristic appearance on plain radiography and CT.

Long-term hemodynamic evaluation of lower extremity percutaneous transluminal angioplasty

Percutaneous transluminal angioplasty (PTA) has provided an alternative method of treatment for occlusive disease of the lower extremities. However, the long-term durability of PTA compared with that of surgical reconstruction has not been adequately evaluated. This study was undertaken to assess the long-term hemodynamic results of PTA. Thirty-four dilatations performed on 28 patients over a 30-month period and followed for 1 to 53 months were reviewed. Twenty-two dilatations were done in the iliac arteries, seven in the superficial femoral, three in the popliteal, one in the peroneal artery, and one at a bypass graft anastomosis. All patients underwent noninvasive measurements of lower extremity segmental pressure prior to dilatation and at scheduled follow-up intervals. Success was defined as an increase in the Doppler-derived segmental lower extremity/brachial index of greater than or equal to 0.15 or normalization of the index (greater than or equal to 0.90), measured at the closest level distal to the site of dilatation. Sixteen of 22 iliac dilatations (72.7%) were initially successful. However, long-term success was maintained in only six (27.6%). Cumulative hemodynamic success for the initially successful iliac dilatations was 28% at 3 years. Seven of 11 (63.6%) dilatations performed on infrainguinal arteries were initially successful; however, only two (18.2%) experienced continued success. Cumulative hemodynamic success for the initially successful infrainguinal dilatations in this group was 35% at 3 years. Although immediate patency and improvement in hemodynamic parameters are similar to comparable surgical procedures, these results demonstrate that PTA is not as durable as conventional surgical procedures.

Diagnosis of traumatic rupture of the gallbladder.

Abstract Possible gallbladder rupture should be considered in any patient with blunt abdominal trauma and vague symptoms who has been inebriated. Peritoneal lavage and endoscopic or percutaneous cholangiography, if feasible, are the preferred diagnostic methods during the initial period after the gallbladder rupture. Later, when encapsulation occurs, ultrasonic examination of the mass together with guided aspiration of the bilious pseudocyst may provide the most useful diagnostic information.

Computed Tomography of the Heart and Great Vessels: Present and Future

Computed tomography (CT) has emerged as a new imaging method for the diagnosis and evaluation of cardiovascular disease. With CT body scanners and contrast enhancement, evaluation of aortic dissections and aneurysms, coronary bypass graft patency, cardiovascular thrombus, cardiac tumors, and pericardial disease is possible. On occasion, this technique provides clinically useful information that is not available with other imaging methods. Electrocardiographic gating retrospectively or prospectively improves the image resolution of CT scans, but a new ultrafast CT scanner with a scan time of 30 to 50 milliseconds offers the greatest promise for expanding the application of the technology for cardiovascular diagnosis. Accurate measurement of cardiac chamber volume, mass, wall motion, and wall thickening will be feasible. Ultrafast CT scanning also shows great promise for the measurement of myocardial infarct size and regional myocardial blood flow.

Ultrasound localization for percutaneous renal biopsy in children.

incidence is much higher: 16 in 123 (1:7) in the series of Whitaker and Danks, 9 and 32 in 101(1:3) in the series of Atwell and associates TM (or 11 in 101, i.e., 1:9 if bifid renal pelvis is excluded), The incidence in our patients with HOODS of nine of 12 pyelograms (1:1.3) showing duplications of the urinary collecting system exceeds by far the incidence in the general population and also the expected incidence in families in which a member was discovered to have a double collecting system. Deteriorating kidney function and renal failure have been described in HOODS, in relation with the microscopic and ultramicroscopic lesions found? 7 The recognition of urinary tract duplication as being a part of HOODS will lead to an alertness toward a correctible situation which may be the cause of renal damage through deranged urinary drainage, stasis, and infection. Although the fortuitous concurrence of these two autosomal dominant traits cannot be ruled out with certainty, the findings in our series suggest that duplications of the renal collecting system pertain to the array of anomalies that may occur in the hereditary osteo-onycho-dysplasia syndrome.