Color-flow Ultrasonography Research Articles

Ultrasonographic Tissue Perfusion in Peri-implant Health and Disease

Color flow ultrasonography has played a crucial role in medicine for its ability to assess dynamic tissue perfusion and blood flow variations as an indicator of a pathologic condition. While this feature of ultrasound is routinely employed in various medical fields, its intraoral application for the assessment of tissue perfusion at diseased versus healthy dental implants has never been explored. We tested the hypothesis that quantified tissue perfusion of power Doppler ultrasonography correlates with the clinically assessed inflammation of dental implants. Specifically, we designed a discordant-matched case-control study in which patients with nonadjacent dental implants with different clinical diagnoses (healthy, peri-implant mucositis, or peri-implantitis) were scanned and analyzed with real-time ultrasonography. Forty-two posterior implants in 21 patients were included. Ultrasound scans were obtained at the implant regions of midbuccal, mesial/distal (averaged as interproximal), and transverse to compute the velocity- and power-weighted color pixel density from color velocity (CV) and color power (CP), respectively. Linear mixed effect models were then used to assess the relationship between the clinical diagnoses and ultrasound CV and CP. Overall, the results strongly suggested that ultrasound’s quantified CV and CP directly correlate with the clinical diagnosis of dental implants at health, peri-implant mucositis, and peri-implantitis. This study showed for the first time that ultrasound color flow can be applicable in the diagnosis of peri-implant disease and can act as a valuable tool for evaluating the degree of clinical inflammation at implant sites.

Giant accessory spleen and rotating ectopic kidney: A rare association

The accessory spleen is a congenital disability characterized by a separated ectopic splenic parenchyma. Wandering spleen (WS) is a rare condition where the spleen, free from its ligaments, is allowed to move inside the abdomen, predisposing the patient to life-threatening complications due to torsion of the vascular pedicle; splenic infarction, portal hypertension, bleeding and acute abdomen may occur. WS or Accessory Spleen (AS) is rarely suspected at presentation since symptoms are usually not specific, and definitive diagnosis is often reached only by imaging technologies such as color flow ultrasonography and angio-spiral computed tomography. The size is rarely more than 4cm. Patients rarely present symptoms, and the diagnosis can be accidental when faced with ectopia in radiological or intraoperative investigations. It is an essential clinical entity since abdomen-pelvic tumors must always be considered as differential diagnoses, requiring detailed evaluation. Surgical treatment is indicated for symptomatic patients or those with complications. On the other hand, the ectopic kidney with rotation abnormality also consists of a singular entity. Congenital anomalies of the upper urinary tract occur in 3%-4% of those born, most of which are followed up clinically. The present study discusses a case of symptomatic intrapelvic WS associated with an ectopic kidney with rotation anomaly, a rare union, and still with scarce reports in the literature. This study aimed to present the case of a patient with an isolated oversized accessory spleen and a review of the literature.

椎骨動脈ステント留置翌日に頸部血管超音波検査で検出された頸動脈ステント留置部可動性血栓の一例

A 60-year-old Japanese man who had undergone stent treatment for stenosis of the left carotid artery received another stent 5 months later to treat a stenotic region of the left vertebral arterial origin. Color flow ultrasonography of the carotid artery before the second stenting procedure revealed good blood flow without any defects in the previous stent. However, the day after implantation of the vertebral arterial stent, carotid color flow ultrasonography identified a new low-echoic mobile structure at the left carotid stent. This structure was diagnosed as thrombus after showing a marked decrease in size after starting anticoagulant therapy. We speculate that the coagulation system, promoted by stent implantation at the vertebral arterial origin, contributed to thrombus formation in the stent at the left carotid artery. Carotid color flow ultrasonography was helpful for detecting low-echoic mobile thrombus in a carotid stent in the present case, and may prove useful for similar future cases.

Improving Medical Imaging and Blood Flow Measurement by using a New Doppler Effect Relationship

The Doppler Effect represents the frequency variation of the waves, received by an observer which is drawing (coming), respectively it’s removing (going), from a wave spring (source). One proposes to study the Doppler Effect for the light waves, generally for the electromagnetic waves. Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842 in Prague. An important application of the Doppler Effect is the medical imaging and blood flow measurement using color flow ultrasonography (Doppler) of a carotid artery-scanner and screen. An echocardiogram can, within certain limits, produce accurate assessment of the direction of blood flow and the velocity of blood and cardiac tissue at any arbitrary point using the Doppler Effect. One of the limitations is that the ultrasound beam should be as parallel to the blood flow as possible. Velocity measurements allow assessment of cardiac valve areas and function, any abnormal communications between the left and right side of the heart, any leaking of blood through the valves (valvular regurgitation) and calculation of the cardiac output. Contrast-enhanced ultrasound using gas-filled micro bubble contrast media can be used to improve velocity or other flow-related medical measurements. Although “Doppler” has become synonymous with “velocity measurement” in medical imaging, in many cases it is not the frequency shift (Doppler shift) of the received signal that is measured, but the phase shift (when the received signal arrives). Velocity measurements of blood flow are also used in other fields of medical ultrasonography, such as obstetric ultrasonography and neurology. Velocity measurement of blood flow in arteries and veins based on Doppler Effect is an effective tool for diagnosis of vascular problems like stenosis. We may improving medical imaging and blood flow measurement by using a new Doppler Effect relationship, presented in this study. With the new proposed Doppler Effect relationship the precision of calculations increase very much and one may do all the measurements much better.

Clinical Implications and Applications of the Twinkling Sign in Ureteral Calculus: A Preliminary Study

Twinkling is an artifact seen on color Doppler ultrasound as a rapidly changing mixture of red and blue behind a stationary echogenic structure. We studied the presence or absence of this artifact in ureteral calculi detected on ultrasound and correlated it with clinical parameters. We evaluated 284 ureteral calculi seen on color Doppler ultrasound. The twinkling artifact was graded as 0 to 2 and correlated with the presence or absence of pain, symptom duration, degree of hydronephrosis and passage of a Glidewire® guidewire across the ureteral calculus during ureterorenoscopy. The presence or absence of twinkling was not associated with the degree of hydronephrosis. Twinkling was absent in 92% of patients with significant pain and grade 2 twinkling was seen in 69.5% without significant pain. Twinkling was dominantly absent in patients with a recent colic episode, while 77% who presented 2 to 15 days after a colic episode had grade 2 twinkling. The guidewire was difficult to pass in cases with absent twinkling compared to those with grade 2 twinkling, in which the guidewire and ureteral catheter crossed the calculus easily. Absent twinkling is associated with significant pain, a recent colic episode and difficult guidewire passage across the calculus. These findings suggest that absent twinkling implies significant obstruction, while its presence indicates no significant obstruction.

Placental Chorioangioma: A Case Report

Chorioangioma constitutes the commonest benign growth of placenta. It consists of a benign angioma arising from chorionic tissue. Chorioangioma of the placenta most often goes unnoticed. With the advent of gray scale and color flow ultrasonography in prenatal diagnosis these tumours can be easily detected antenatally. It has potentially serious fetal risks and so the pregnancy needs to have regular surveillance. The larger the size of the tumor the more is the chance of developing complications. We present a case with large chorioangioma without any serious complications and a successful outcome.DOI: http://dx.doi.org/10.3329/birdem.v2i2.12326(Birdem Med J 2012; 2(2): 113-115)

Gestating for 22 months: luteal development and pregnancy maintenance in elephants

The corpus luteum, a temporally established endocrine gland, formed on the ovary from remaining cells of the ovulated follicle, plays a key role in maintaining the early mammalian pregnancy by secreting progesterone. Despite being a monovular species, 2-12 corpora lutea (CLs) were found on the elephant ovaries during their long pregnancy lasting on average 640 days. However, the function and the formation of the additional CLs and their meaning remain unexplained. Here, we show from the example of the elephant, the close relationship between the maternally determined luteal phase length, the formation of multiple luteal structures and their progestagen secretion, the timespan of early embryonic development until implantation and maternal recognition. Through three-dimensional and Colour Flow ultrasonography of the ovaries and the uterus, we conclude that pregnant elephants maintain active CL throughout gestation that appear as main source of progestagens. Two LH peaks during the follicular phase ensure the development of a set of 5.4 ± 2.7 CLs. Accessory CLs (acCLs) form prior to ovulation after the first luteinizing hormone (LH) peak, while the ovulatory CL (ovCL) forms after the second LH peak. After five to six weeks (the normal luteal phase lifespan), all existing CLs begin to regress. However, they resume growing as soon as an embryo becomes ultrasonographically apparent on day 49 ± 2. After this time, all pregnancy CLs grow significantly larger than in a non-conceptive luteal phase and are maintained until after parturition. The long luteal phase is congruent with a slow early embryonic development and luteal rescue only starts 'last minute', with presumed implantation of the embryo. Our findings demonstrate a highly successful reproductive solution, different from currently described mammalian models.

Ultrasound Surveillance of Endovascular Aneurysm Repair: A Safe Modality versus Computed Tomography

Routine ultrasound surveillance is adequate and safe for monitoring endovascular aneurysm repairs (EVARs). A retrospective chart review including 160 endograft patients was performed from August 2000 to September 2005. All ultrasound examinations (n = 359) were performed by a board-certified vascular surgery group's accredited laboratory. Registered vascular technologists utilized the same equipment consisting of Siemens Antares high-definition ultrasonography with tissue harmonics and color flow Doppler. An identical protocol was followed by each technologist: scan body and both limbs of the endograft and distal iliac vessels, measure anterior-posterior aneurysm sac size, and detect intrasac pulsatility and color flow. Statistical analysis utilized Pearson's correlation coefficient and the paired t-test. Forty-one endoleaks were discovered out of the 359 exams (11.4%). There were type I (7, 17%), type II (26, 63%), and combined type I with type II (8, 20%) endoleaks. Correlation with computed tomography (CT) was obtained in 35 of these cases. CT discovered three endoleaks that were not seen with ultrasound. However, these particular ultrasound exams were inadequate due to additional factors (bowel gas, body habitus, hernia), which prompted CT investigation and, hence, endoleak discovery. Of the 41 endoleaks found on ultrasound, only 14 were seen on CT. Specifically, 26 type II endoleaks were seen with ultrasound versus only nine during CT. Additional factors addressed included comparison between ultrasound and CT of residual aneurysm sac measurements and conditions limiting ultrasound examination. Although criticized in the past, color flow ultrasonography is a safe and effective modality for surveillance of aortic endografts. Utilizing ultrasound to analyze abdominal aortic aneurysm (AAA) sac dimensions and endoleak detection is statistically sound for screening AAA status post-EVAR.

Retrievable Inferior Vena Cava Filters: Initial Clinical Results

Anticoagulation is the accepted therapy for patients with thromboembolic disease. When contraindications to anticoagulant therapy are present, however, interruption of the inferior vena cava (IVC) may prevent pulmonary embolism (PE). The objective of this study was to report our early technical and clinical results with retrievable IVC filters (IVCFs) for the prevention of PE. One hundred and twenty-seven multitrauma patients between December 1, 2002, and December 31, 2004, underwent placement of Gunther-Tulip (n = 49), Recovery (n = 41), or OptEase (n = 37) retrievable IVCFs under real-time intravascular ultrasound (IVUS) guidance. All patients had abdominal X-rays to verify filter location. Prior to IVCF retrieval, all patients underwent femoral vein color flow ultrasonography to rule out deep vein thrombosis (DVT) and vena-cavography to assess the IVCF for trapped emboli, filter tilt, or retrained thrombus. Thirty-nine patients died of their injuries; no deaths were related to IVCF placement. One PE occurred during follow-up after filter retrieval, and two femoral vein insertion-site DVTs occurred. One hundred twenty (94.4%) of IVCFs were placed without complication at the L2-3 level, as verified by abdominal X-rays. Filter-related complications included three groin hematomas (2.9%) and three IVCFs misplaced in the right iliac vein early in our experience (2.3%); these filters were uneventfully retrieved and replaced in the IVC within 24 hr. Sixty-six patients underwent uneventful retrieval of IVCFs after DVT or PE anticoagulation prophylaxis was initiated. Forty-five IVCFs were not removed: 41 due to contraindications due to anticoagulation and four because of trapped thrombus within the filter. The role of retrievable IVCFs continues to evolve, but in this study of 127 patients, prophylactic temporary IVCF placement was simple and safe, prevented fatal PE, and served as an effective "bridge" to anticoagulation. Further investigation of this bedside IVUS technique and the role of temporary IVCFs in different patient populations is warranted.

Optimizing Doppler and color flow US: application to hepatic sonography.

In the imaging of patients with chronic liver disease or portal hypertension or who have undergone liver transplantation or surgery, accurate evaluation of the hepatic vasculature is usually necessary. Because Doppler ultrasonography (US) is capable of accurately characterizing the nature of flow within the major hepatic arteries and the portal and hepatic veins, it is widely used for imaging the liver vasculature. An informed choice of transducer and scanning techniques is important in the evaluation of the liver vasculature. In addition, there are a variety of operator-dependent technical parameters (eg, baseline, frame rate, wall filters, gain, velocity range, angle correction, gate size and position) that must be optimized when performing Doppler US of the liver. Changes in these parameters independently influence both the color and spectral components of the Doppler US examination; therefore, the parameters should be optimized separately for each patient. Failure to appropriately adjust these parameters may result in artifacts or misinterpretation of the study, which will frequently affect patient treatment. In contrast, knowledge of these operator-dependent parameters will permit optimization of the study and improve the overall utility of liver Doppler US.

The Saphenofemoral Valve: Gate Keeper Turned into Rear Guard

Objective: Trendelenburg's theory was based on the concept of a descending valvular incompetence com mencing at the saphenofemoral junction (SFJ) with subsequent distal progression of reflux. The aim of this study was to evaluate the distribution of reflux in patients with superficial venous incompetence in order to assess validity of the above hypothesis. Procedures: The superficial and deep venous system of a consecutive series of 443 patients presenting with primary varicose veins was examined by one vascular technologist using colour flow ultrasonography. Results: Six hundred and eleven lower limbs in 443 patients were examined. The distribution of long saphenous vein (LSV) reflux was the following: Of the 611 limbs 454 showed LSV reflux, with 240 legs exhibiting total reflux (SFJ and LSV) and 214 legs exhibiting reflux in evolution (LSV reflux with competent saphenofemoral valve, isolated posterior arch reflux and lateral anterior thigh vein reflux with SFJ reflux). Conclusion: These results suggest that reflux starts distally and progresses proximally, thus throwing the Trendelenburg theory into dispute.

Popliteal Artery Aneurysms: Is Endovascular Reconstruction Durable?

Purpose:To describe an endovascular method of performing femoropopliteal in situ saphenous vein (SV) bypass and popliteal artery aneurysm (PAA) embolization.Methods:Twenty-two patients underwent PAA operations. Twelve patients had conventional SV bypasses with PAA proximal and distal ligation, whereas 10 underwent PAA embolization and an endovascular in situ SV bypass (EISB). The endovascular procedure was performed using an angioscopically guided side branch coil occlusion system. The PAAs were coil embolized under fluoroscopic surveillance.Results:No deaths or wound complications occurred in the EISB group. The mean hospital length of stay (LOS) was 2.1 days. Seven EISB procedures were performed through 2 incisions, whereas 3 operations required an additional incision. One graft occluded at 3 months. All PAAs remained occluded by color-flow ultrasonography at follow-up ranging from 4 to 23 months (mean 13.6); cumulative primary patency was 89%. In the conventional bypass group, no deaths occurred, but 3...

Use of ultrasound contrast in the diagnosis of carotid artery occlusion.

The purpose of this study was to evaluate the use of an echo-enhancing agent in patients with carotid artery occlusion to improve the sensitivity and specificity of carotid color flow ultrasonography. Between January 1997 and December 1998, a prospective study involving 85 cases of carotid artery occlusion in 84 patients was carried out. After a baseline duplex ultrasonography (DU) diagnosis, a second (DU) along with an echo-enhancement agent (SHU-508-A [Levovist]) study was carried out (echo enhancement ultrasonography diagnosis [DUEE]). In 82 cases, a contrast angiography was performed to confirm the diagnosis, whereas in the other three cases the diagnoses were confirmed with surgery. From the 85 internal carotid artery occlusions diagnosed at the initial DU examination, seven came out to be false occlusions in the DUEE examination (8,2%). There was a 100% correlation of the cases between the DUEE examination and the contrast angiography in the 82 cases in which this had been done. In three of the cases, the diagnosis was confirmed surgically because these displayed severe stenoses according to the DUEE studies in symptomatic patients, and so they required urgent treatment. The DUEE study is a potent diagnosis tool that allows the differentiation between true carotid artery occlusions and pseudo-occlusions.

Popliteal Artery Aneurysms: Is Endovascular Reconstruction Durable?

-This initial series describes a minimally invasive, endovascular method of performing femoropopliteal in situ saphenous vein (SV) bypass and popliteal artery aneurysm (PAA) embolization. Twenty patients have undergone PAA operations. Eleven patients had conventional SV bypasses with proximal and distal ligation of the popliteal artery (PA), and nine patients underwent PAA embolization and an endovascular in situ SV bypass (EISB). The EISB bypass was performed using an angioscopic guided side branch occlusion coil system, whereas the PAAs were embolized with occlusion coils under fluoroscopic surveillance. After operation in the EISB group there were no deaths, no wound complications, and the mean hospital length of stay (LOS) was 2.1 days. Six operations were performed through two incisions, and three operations required an additional incision. Primary patency was 88% (8/9), and all PAAs remained occluded by color flow ultrasonography at follow-up ranging from 4 to 23 months (mean 11.2 months). In the conventional bypass group there were no deaths, three patients (27%) had wound complications, and the mean LOS was 6.2 days. Bypass patency at 42 months was 91% (10/11). This minimally invasive combined radiological and endovascular surgical technique obviates an extensive incision to harvest the SV and ligate the PAA proximally and distally. If long-term endovascular bypass graft patency and PAA occlusion rates prove to be similar to open operative results, the benefits of reduced wound complications, decreased hospital LOS, and increased health care savings support further investigation of this endovascular method for the treatment of PAA.

Popliteal Artery Aneurysms: Is Endovascular Reconstruction Durable?

This initial series describes a minimally invasive, endovascular method of performing femoropopliteal in situ saphenous vein (SV) bypass and popliteal artery aneurysm (PAA) embolization. Twenty patients have undergone PAA operations. Eleven patients had conventional SV bypasses with proximal and distal ligation of the popliteal artery (PA), and nine patients underwent PAA embolization and an endovascular in situ SV bypass (EISB). The EISB bypass was performed using an angioscopic guided side branch occlusion coil system, whereas the PAAs were embolized with occlusion coils under fluoroscopic surveillance. After operation in the EISB group there were no deaths, no wound complications, and the mean hospital length of stay (LOS) was 2.1 days. Six operations were performed through two incisions, and three operations required an additional incision. Primary patency was 88% (8/9), and all PAAs remained occluded by color flow ultrasonography at follow-up ranging from 4 to 23 months (mean 11.2 months). In the con...

Characterization of Urinary Calculi: In Vitro Study of “Twinkling Artifact” Revealed by Color-Flow Sonography

Characterization of Urinary Calculi: In Vitro Study of “Twinkling Artifact” Revealed by Color-Flow Sonography

Characterization of Urinary Calculi: In Vitro Study of “Twinkling Artifact” Revealed by Color-Flow Sonography

The is a color-flow sonographic artifact described behind calcifications and presenting as a random color encoding in the region where shadowing would be expected on gray-scale images. Our purpose was to study the relationship between this twinkling artifact seen behind urinary stones on color-flow sonography and the morphology or biochemical composition of these urinary stones.Forty-seven urinary stones were studied in vitro with color-flow sonography. Transmit frequency, color gain, velocity range, color filters, focal depth, and depth of field were changed during scanning. The twinkling artifact was graded 0 when absent, 1 when present but occupying a portion of acoustic shadowing, and 2 when occupying the entire acoustic shadowing. Stones were studied under a binocular magnifying glass to characterize the surface, and infrared spectrophotometry was used to determine the chemical composition.Calculi of calcium oxalate dihydrate and calcium phosphate always produced a grade 1 or gra...

Sites of stenosis in AV fistulae for haemodialysis access.

A large proportion of late failures of radiocephalic arteriovenous fistulae are related to the progression of intimal hyperplasia. The aetiology of this process is still unknown but the fistula configuration and resultant haemodynamics have been implicated. This clinical study was devised to identify sites of stenosis in patients with fistulae and relate the findings to various clinical and geometrical parameters. Measurement of anastomotic length and angle was made intraoperatively in 25 consecutive fistulae. Post-operative assessment was carried out at regular intervals using duplex and colour-flow ultrasonography. Stenoses were present in all 25 of the fistulae studied at 3 months. The stenoses could be classified to three specific sites: at the anastomosis (Type 1), on the inner wall of the curved region of the cephalic vein (Type 2) and just proximal to this curved segment where the vein straightens out (Type 3). Most of Type 1 and Type 2 stenoses were not progressive while Type 3 stenoses were generally progressive. These findings emphasize the need for an effective surveillance programme of AV fistulae.

Characterizing flow distributions in AV fistulae for haemodialysis access.

The arteriovenous fistula is the most widely used means of enabling vascular access for chronic haemodialysis. When interest in vascular access was at its height, in the 1970s, a substantial amount of work was carried out on the physiology of arteriovenous fistulae and on the relationship between fistula flow and patency. One omission in the catalogue of studies was research into the distribution of flow in the fistula and the effects on surgical outcome. To address this issue, 30 patients with end-to-side radiocephalic fistulae were studied. Flow measurements were made intraoperatively, and at various intervals postoperatively using colour-flow ultrasonography. In 22 cases, the development of the fistula was monitored at regular intervals for periods of up to 27 months. In seven of the 30 fistulae, flow in the distal artery was antegrade, while in the remaining 23, distal artery flow was retrograde. The proportion of fistula flow supplied by the proximal and distal arteries varied considerably. Despite the wide range of flow distributions in the fistulae studied, flow distribution did not appear to affect fistula maturation or long-term function.

Characterization of urinary calculi: in vitro study of "twinkling artifact" revealed by color-flow sonography.

The "twinkling artifact" is a color-flow sonographic artifact described behind calcifications and presenting as a random color encoding in the region where shadowing would be expected on gray-scale images. Our purpose was to study the relationship between this twinkling artifact seen behind urinary stones on color-flow sonography and the morphology or biochemical composition of these urinary stones. Forty-seven urinary stones were studied in vitro with color-flow sonography. Transmit frequency, color gain, velocity range, color filters, focal depth, and depth of field were changed during scanning. The twinkling artifact was graded 0 when absent, 1 when present but occupying a portion of acoustic shadowing, and 2 when occupying the entire acoustic shadowing. Stones were studied under a binocular magnifying glass to characterize the surface, and infrared spectrophotometry was used to determine the chemical composition. Calculi of calcium oxalate dihydrate and calcium phosphate always produced a grade 1 or grade 2 twinkling artifact. Absence of artifact was noted only for calcium oxalate monohydrate and urate stones. In 100% of grade 0 calcium oxalate stones, the monohydrate compound was predominant (>93%). In 100% of grade 2 calcium oxalate stones, the dihydrate compound was predominant (>75%). For calcium oxalate stones, the surface pattern was correlated with their composition. Sensitivity and specificity for absence of artifact, as indicative of calcium oxalate monohydrate, were 60% and 83%, respectively, for all stones and 56% and 100%, respectively, only for radiopaque stones. An in vitro relationship exists between the twinkling artifact and the morphology of urinary stones. Color-flow sonography could play a role in detecting dense calcium oxalate monohydrate calculi, which in turn may help predict fragmentability.