True knot of the umbilical cord is a rare condition (up to 1.25% of pregnancies(Ref#1)) with the highest rate occurring in monoamnionic twins. It is difficult to diagnose this with prenatal ultrasound because sonographers are not generally looking for this condition. True knots arise from fetal movements and are more likely to develop during early pregnancy, when relatively more amniotic fluid is present and greater fetal movement occurs. Constriction of a true knot is not common but it may lead to obstruction of the fetal circulation and subsequent intrauterine death. In fact, fetuses with true umbilical knots are at a four-fold increased risk of intrauterine death(Ref#2). It has been reported that true knots are associated with(Ref#1 and #2):
– Advanced maternal age
– Previous miscarriages
– Prolonged gravidity
– Male fetus
– Long cord
– Maternal anemia
– Maternal chronic hypertension
Pulsed wave Doppler spectral analysis can be used to demonstrate a stenotic effect on the umbilical venous blood flow post-stenosis (Ref#3). A pre stenotic dilation of the umbilical vein can also be seen. A cesarean delivery may be considered if a diagnosis of a true cord knot is made.
1) Airas U, Heinonen S. Clinical significance of true umbilical knots: a population-based analysis. Am J Perinatol 2002 Apr;19(3):127-32.
2) Hershkovitz R, Silberstein T, Sheiner E, Shoham-Vardi I, Holcberg G, Katz M, Mazor M. Risk factors associated with true knots of the umbilical cord. Eur J Obstet Gynecol Reprod Biol 2001 Sep;98(1):36-9.
3) Gembruch U, Baschat AA. True knot of the umbilical cord: transient constrictive effect to umbilical venous blood flow demonstrated by Doppler sonography. Ultrasound Obstet Gynecol 1996 Jul;8(1):53-6.
Cor triatriatum sinister is a rare cardiac anomaly in which a fibromuscular band, fold of tissue or membrane divides the left atrium into two. It has an incidence of 0.1 to 0.4% . The age of presentation usually depends on the size of the communicating orifice between the chambers. If the orifice is small, the patient is gravely ill and may succumb to congestive heart failure during infancy. If the orifice is larger the patient may present later in life – even adulthood in cases of a non obstructive anomaly.
– diminished peripheral pulses
– physical size smaller than expected
– heart murmur
– may be asymptomatic
– atrial myxoma / tumor
– mitral stenosis
– supravalvular mitral ring
– anomalous pulmonary venous drainage to the coronary sinus
Approximately 75% of patients die in infancy (generally from pulmonary hypertension) if the defect is unrepaired by surgery.
The finding evident on the case of the week is an intra-atrial membrane visible in both parasternal and apical examination planes. The membrane is seen to insert some distance away from the mitral valve annulus. Superiorly the membrane runs nearly parallel to, and a short distance behind, the aortic root creating a superior recess of the distal left atrial chamber.
During diastole there is subtle motion of the membrane toward the mitral valve funnel. This, together with the arching appearance of the membrane on the four chamber view and the more superior position of the membrane, favors the diagnosis of cor triatriatum versus total anomalous pulmonary venous drainage to the coronary sinus (which may coexist). Attempts to identify the origin of each pulmonary vein would further assist with this differentiation.
In this case, although Doppler waveforms were not submitted with the case, the color Doppler exhibits no turbulence so a non restrictive abnormality is presumed.
Gamma-Gandy Bodies (GGB): Sonogram of the spleen in a patient with portal hypertension demonstrates numerous small echogenic foci without acoustic shadowing.
Sonographic Features of GGB: On sonography, GGB are seen as punctuate, bright echogenic foci scattered in the parenchyma. They may or may not cause acoustic shadowing posterior to these foci depending on the amount of calcification present within them. Portal hypertension may also show the presence of reflector channels in the spleen, which is actually the sclerotic splenic vein wall secondary to portal hypertension. These channels may be distinguished from GGB by the presence of flow within them on color flow Doppler imaging. Unfortunately, most of these cases are missed on ultrasound by sonographers who are not aware of these nodules.
Gamna-Gandy bodies (also known as siderotic nodules or tobacco flecks) are small, firm nodules of fibrous tissue impregnated with iron pigment (hemosiderin) and calcium salts that occur chiefly in the spleen but more commonly in conditions such as congestive splenomegaly and sickle cell anemia. They have also been rarely reported in cardiac myxomas. The GGB in the spleen are thought to be a result of healed focal hemorrhages and necrosis in the splenic parenchyma secondary to congestive splenomegaly, followed by accumulation of hemosiderin and impregnation of collagen and elastic fibers with iron and calcium.
Origin of GGB. Gamna-Gandy bodies were first described by Marini in 1902. They were later reported by Charles Gandy (French physician) and Carlo Gamna (Italian physician) in 1905 and 1921, respectively, giving the eponym to the entity. Because of the resemblance of the histologic features of GGB to mycelial structures, these lesions were initially thought by some authors to have a fungal origin. The thought was completely discarded after definite microbiologic studies of GGB were published in 1931.
Causes of GGB. Portal hypertension is the most common cause of GGB in the spleen and is seen in about 9% to 12% of these patients. Gamna-Gandy bodies in the spleen have also been seen in conditions such as paroxysmal nocturnal hemoglobinuria, hemolytic anemia, sickle cell anemia, leukemia, and lymphoma, in patients receiving blood transfusions, in angiosarcoma, and in acquired hemochromatosis. However, it is not clear whether GGB in these conditions are a direct result of the condition themselves or are a result of underlying portal hypertension. Uncommonly, GGB have also been reported in other organs besides the spleen.
Superficial venous insufficiency is most often caused by the failure of a valve in the superficial venous system. Greater than 80% of varicose veins seen on the leg are caused by chronic venous insufficiency (CVI) or a leaky valve in the great saphenous vein (GSV), which terminates near the inguinal ligament as it joins the common femoral vein. The saphenofemoral junction is the high point of reflux in most patients with severe superficial venous insufficiency. Valve failure can be spontaneous in patients with congenitally weak valves. Congenitally normal valves can fail due to direct trauma, thrombosis, hormonal changes, or chronic environmental insult (eg, prolonged standing).
Most cases of superficial vein valve failure occur after primary points of high-pressure leakage develop between the deep system and the superficial system. High pressure causes secondary valve failure when otherwise normal superficial veins become so widely dilated that the thin flaps of the venous valves can no longer make contact in the lumen of the vessel resulting in visibly dilated and tortuous veins, at which point they are recognized as varicose veins.
Junctional high-pressure disease most often results from failure of the primary valve at the junction between the greater saphenous vein and the common femoral vein (CFV) at the groin (saphenofemoral junction). Vein incompetence then proceeds distally from the groin, and patients perceive that a large vein is growing down their leg. A less common form of junctional reflux results from failure of the primary valve at the junction between the short saphenous vein (SSV) and the popliteal vein (PV) at the knee (saphenopopliteal junction).
Perforator high-pressure disease results from failure of the valves of any perforating vein. The most common sites of primary perforator valve failure are in the midproximal thigh (Hunterian perforator) and in the proximal calf (Boyd perforators). When the primary high-pressure entry point is distal, large clusters of veins are first noticed in the lower leg, with large veins eventually growing up the leg toward the groin.
Frequency of venous insufficiency is believed to be higher in Westernized and industrialized nations (about 40% of the population), most likely due to differences in lifestyle and activity. The incidence and prevalence of deep and superficial venous disease depend on the age and sex of the population, but the prevalence in women exceeds that of men at any age. In younger men, the incidence is less than 10%, compared with 30% in similarly aged women. In men over 50 years of age, the incidence is 20%, compared with 50% in similarly aged women. The prevalence of venous insufficiency increases with age.
Duplex ultrasonography is the study of choice for the evaluation of venous insufficiency syndromes as it is both sensitive and specific. Ultrasonographic reflux mapping is essential for the evaluation of peripheral venous insufficiency syndromes. Dynamic color Doppler flow imaging is a useful technique to easily demonstrate the reversal flow in an incompetent venous valve as demonstrated in the video clip above. On the image, the color blue at rest (which in this case represents the normal venous flow to the heart) is reversed to color red (which in this case represents the reflux of the blood flow through the impaired valve down to the leg) during the valsalva maneuver.
Venous insufficiency is neither uncommon nor benign. Treatment is aimed at improve the symptoms and, whenever possible, at correcting the underlying abnormality. Deep system disease is often refractory to treatment, but superficial system disease can usually be treated by ablating the refluxing vessels. Refluxing superficial vessels can safely be removed or ablated without sequelae; an incompetent vessel has already proved itself unnecessary because it is carrying venous blood in a retrograde direction. All methods of venoablation are effective. Once the overall volume of venous reflux is reduced below a critical threshold by any mechanism, venous ulcerations heal, and patient symptoms are resolved. Variceal hemorrhage is best managed by means of primary sclerotherapy. Endovenous laser therapy (EVT) has been shown to have excellent results (more than 5 years) and a low rate of complications. Radiofrequency ablation (RFA) has been show to be effective, with a low rate of complications. It has produced excellent results that have been confirmed with up to 10 years of follow-up. Vein stripping with ligation of the saphenofemoral junction was the most common surgical approach in cases of superficial venous insufficiency but has been replaced by endovenous ablation techniques such as RFA and EVT.
emedicine.medscape.com, Venous Insufficiency
Hamid Tahmasebpour, CRGS, Clinical Instructor, Department of Radiology, University of British Columbia, Vancouver, BC
Endometrial Waves or Contractile Waves
The uterus frequently contracts throughout the entire menstrual cycle, and these contractions have been termed endometrial waves or contractile waves. These waves are governed by steroid hormones and they appear to involve only the sub-endometrial layer of the myometrium. In the early follicular phase, these contractions occur once or twice per minute and last 10–15 seconds with a low amplitude of usually 30 mmHg. The frequency increases to 3–4 per minute towards ovulation. During the luteal phase, the frequency and amplitude decrease, possibly to facilitate any implantation.
If implantation does not occur, the frequency remains low, but the amplitude increases dramatically to between 50 and 200 mmHg producing labor-like contractions at the time of menstruation. These contractions are sometimes termed menstrual cramps, although that term is often used for menstrual pain in general. These contractions may be uncomfortable or even painful (as in this patient), but they are generally significantly less painful than contractions during labour. A hot water bottle or exercising has been found to help.
A shift in the myosin expression of the uterine smooth muscle has been hypothesized to avail for changes in the directions of uterine contractions that are seen during the menstrual cycle (From Wikipedia, the free encyclopedia).
The thickened hypervascular endometrium in this retroflexed uterus was suspicious for malignancy but the observation of “endometrial waves” demonstrated an edometrial polyp.
2 tiny stones were detected by color Doppler twinkling artefact which they were otherwise unrecognizable on grey scale images. Small renal stones (less than 4 mm) may go undetected at routine ultrasonography due to lack of acoustic shadowing. However, twinkling artefact is a very useful color Doppler artefact that may assist in detecting renal stones as small as 1-2 mm. The twinkling artefact is a random strong reflection of the incident ultrasound beam at a rough surface formed by material such as calcium or cholesterol deposits. The twinkling artifact is independent of the color velocity scale and cardiac cycle. With increasing color velocity scale, the color flow within blood vessels may disappear (as demonstrated in this case where the color velocity scale set at 88 cm/s) while the artifactual color from the stone will continue to twinkle. This is an easy method of differentiating the twinkling artifact from color flow in blood vessels. A large parapelvic cyst is also noted.
Tahmasebpour HR et al: Sonographic Examination of Carotid Arteries. RadioGraphics 2005; 25:1561–1575
Peroneus Longus (PRL) Calcific Tendinits
Calcific tendinitis of the peroneus longus tendon is extremely rare, with only two cases described previously in the literature.
The calcific deposits may be located within the tendon or in the soft tissues adjacent to the tendon or ligament near its attachment to the bone. Calcific tendinitis is presented as an acute inflammatory reaction, associated with pain, local tenderness, swelling and redness. Misdiagnosis is common and leads to delay in treatment and recovery
The PRL muscle originates on the proximal and mid lateral fibula and fans along the plantar surface of the foot to insert on the plantar aspect of the base of the 1st metatarsal and the medial cuneiform. The peroneus brevis (PRB) muscle originates on the mid and distal lateral fibula and inserts on the base of the 5th metatarsal. The PRL and PRB tendons are located on the posterolateral aspect of the ankle, passing posterior and inferior to the lateral malleolus. The tendons run within a retromalleolar groove on the back of the fibula and are held in place along the lateral malleolus by the superior peroneal retinaculum. Next to the calcaneus they may be separated by the calcaneus’ peroneal tubercle, with the PRB anterior to the tubercle; or both may pass anterior to the tubercle. The PRL tendon crosses on the plantar aspect of the PRB before insertion. The PRL and PRB are the major foot everters, using the lateral malleolus as a pulley.
A major concern when diagnosing a pancreatic cancer is whether or not the cancer has already spread (metastasized) outside of the pancreas. The location of the metastases will determine whether the patient has locoregional or metastatic disease.The location of the metastases will also determine whether the cancer is able to be surgically removed (resectable) or unable to be surgically removed (unresectable). Metastases to the liver are a common finding especially with tumors in the tail and the body of the pancreas. Usually, if there is evidence of liver “mets,” surgery will not be an option.
A small hyperechoic area (air bubbles) was identified in the duodenal bulb which did not disappear with the peristaltic movements. The hyperechoic area is surrounded by hypoechoic halo in various thicknesses representing duodenal wall edema and infiltration. While not recommending ultrasonography in the detection of ulcer disease, the ultrasonographic pattern of an ulcer should be recognized so that when it is seen, an upper gastrointestinal series can be performed as the next diagnostic study. Ultrasonography may also depict subphrenic and other collections resulting from a perforated duodenal ulcer.
Anatomy: The duodenal bulb is the portion of the duodenum which is closest to the stomach. It normally has a length of about 5 centimeters. The duodenal bulb begins at the pylorus and ends at the neck of the gallbladder. It is located anterior to the liver and the gallbladder, and superior to the pancreatic head. The gastroduodenal artery, portal vein, and common bile duct lie just behind it. The distal part of the bulb is located retroperitoneally. It abuts the Pyloric sphincter. The duodenal bulb is the place where duodenal ulcers occur.
Duodenal ulcers are more common than gastric ulcers and, unlike gastric ulcers, are caused by increased gastric acid secretion. Duodenal ulcers are commonly located anteriorly, and rarely posteriorly. Anterior ulcers can be complicated by perforation, while the posterior ones bleed. The reason for that is explained by their location. The peritoneal or abdominal cavity is located anterior to the duodenum. Therefore, if the ulcer grows deep enough, it will perforate; whereas if a posterior ulcer grows deep enough, it will perforate the gastroduodenal artery and bleed.
Superior mesenteric vein (SMV) thrombosis is a well known complication of pancreatic cancer. This condition is not surprising as the SMV runs in close association with the neck of pancreas. Thus, any inflammation let alone malignancy may involve the SMV. Inflammation may induce spasm resulting in stasis and subsequent intimal damage thereby predisposing to thrombosis. Pancreatic carcinoma may cause SMV thrombosis by direct invasion, extrinsic compression via mass effect, or hypercoagulable state. In this case, the pancreatic cancer was located in the neck of the pancreas with consequent development of varices and shunt between the SMV and the systemic venous return as demonstrated on the image below. Therefore, documentation of SMV during any routine abdominal ultrasound examination is highly recommended.
Epigastric hernias are usually present at birth and the fibrous tissues in the abdomen will usually fully close as the child develops. Epigastric hernia is a type of hernia which may develop in the epigastrium (upper, central part of the abdomen). Epigastric hernias may develop in obese adults or after pregnancy. Unlike the benign diastasis recti, epigastric hernia may trap fat and other tissues inside the opening of the hernia, causing pain and tissue damage. Symptomatic epigastric hernias are repaired with surgery. Even if they are asymptomatic, they can be surgically corrected for cosmetic reasons. In general, cosmetic surgery on infants is delayed until the infant is older and better able to tolerate anaesthesia.
(Reference: From Wikipedia, the free encyclopedia)
In this patient, the hernia is in the linea alba (between the rectus muscles) and it contains only fat. The video clip demonstrates small movements of herniated fat while the patient is bearing down with no evidence of bowel involvement. The movement of the herniated structure is an ensuring sign that the herniated structure is neither incarcerated nor strangulated.
The speed of sound within a material is dependent on its density and elastic properties. Ultrasound image processing assumes a constant speed of sound in human tissue of 1540 m/sec. In clinical sonography, the ultrasound beam may encounter a variety of materials such as air, fluid, fat, soft tissue, and bone. When sound travels through material with a velocity significantly slower than the assumed 1540 m/sec, the returning echo will take longer to return to the transducer. The image processor assumes that the length of time for a single round trip of an echo is related only to the distance traveled by the echo. The echoes are thus displayed deeper on the image or further lateral than they really are. This is referred to as the speed displacement artifact; in clinical imaging, it is often recognized when the ultrasound beam encounters an area of focal fat such as perirenal fatty tissue in this case. A change in velocity of the ultrasound beam as it travels through two adjacent tissues with different density and elastic properties may produce a refraction artifact. In refraction, nonperpendicular incident ultrasound energy encounters an interface between two materials with different speeds of sound. When this occurs, the incident ultrasound beam changes direction. The degree of this change in direction is dependent on both the angle of the incident ultrasound beam and the difference in velocity between the two media. The ultrasound display assumes that the beam travels in a straight line and thus misplaces the returning echoes to the side of their true location. In clinical imaging, this artifact may also be recognized in pelvic structures deep to the junction of the rectus muscles and midline fat. Refraction artifact may cause structures to appear wider than they actually are or may cause an apparent duplication of structures as demonstrated in this case in the upper pole of the left kidney which is disappeared with deep breathing when the kidney is located.
Reference: Feldman MK et al: US Artifacts. RadioGraphics 2009; 29:1179–1189