Hyperechoic Center Research Articles

“Dot-in-circle sign:” An ultrasound and magnetic resonance imaging sign for mycetoma

Mycetomas are chronic infections of the skin, underlying soft tissues, and sometimes extending up to the bones. They can be actinomycetoma or eumycetoma. Mycetoma is more frequent in tropical and subtropical regions. The definitive diagnosis is made by histopathology and culture in most cases, but these procedures are invasive and time consuming. “Dot-in-circle sign” is an important sign present on both ultrasound (USG) and magnetic resonance imaging (MRI) which imply the presence of distinct hypoechoic lesions surrounding a hyperechoic center. The use of these imaging modalities can help in the early diagnosis and preventing complications. We report two cases of eumycetoma affecting the feet, with characteristic USG and MRI features.

Anatomic, computed tomographic, and ultrasonographic assessment of the lymph nodes in presumed healthy adult cats: the abdomen, pelvis, and hindlimb

BackgroundThe computed tomography (CT) and ultrasonography (US) features of lymph nodes of the abdomen, pelvis, and hindlimb in healthy cats are poorly described in the current literature. A prospective anatomic and reference interval study was therefore performed. The lymph nodes of six feline cadavers were identified, and dimensions were measured (length, width, and height). The lymph nodes from 30 healthy adult cats were identified and measured using CT (pre- and postcontrast) and US. The identification and dimensions of the separate lymph nodes were compared between imaging techniques and the anatomic study.ResultsThe identification of lymph nodes was most frequent in CT, and the dimensions were overall larger than those identified and measured in US and the anatomic study. The caudal epigastric and sacral lymph nodes were not identified in the anatomic study. The ischiatic, lumbar aortic, internal iliac, and caudal epigastric lymph nodes were not visualized in US. The height presented the main statistical differences among techniques. The lymph nodes were mainly homogeneous in pre- and postcontrast CT and US images. Some lymph nodes showed a hyperattenuating periphery with a hypoattenuating center (on pre- and postcontrast images) and a hypo-/isoechoic periphery with a hyperechoic center, representing the hilar fat. The lymph nodes were commonly elongated and rounded except for the jejunal lymph nodes, which had an irregular shape.ConclusionsThe assessment of most of the abdominal, pelvic, and hindlimb lymph nodes in the cat is feasible using CT and US, with CT performing best. Factors like the amount of adipose tissue and contrast administration subjectively improved the lymph node visualization and assessment. The measurements and features reported are proposed as reference values.

An ultrasonographic study to evaluate the correlation of calcified yolk sac with spontaneous abortion

Background: The yolk sac is a small, membranous structure, which is situated outside the embryo and has a variety of functions during embryonic development. The yolk sac plays an important role in critical biological functions during early gestation, which includes primitive hematopoiesis as well as production of germ cells. It can be visualized between 6 and 12 weeks of pregnancy by ultrasonography as a regularly rounded extra-amniotic structure when the gestational sac reaches dimensions of 8–10 mm. On sonography, the yolk sac appears as a round structure which has an anechoic center bordered by a regular well-defined echogenic rim. Thus, a normal yolk sac is a yolk sac with echogenic rim and hypoechoic center, whereas yolk sac with hypoechoic rim or hyperechoic center is considered as calcified yolk sac. Aim and Objectives: To study the correlation of calcified yolk sac with spontaneous abortion in the first trimester of pregnancy. Materials and Methods: We studied 144 pregnant females who were in their first trimester of pregnancy, referred by the department of obstetrics and gynecology. The echotexture of yolk sac was observed by transvaginal sonography and its correlation with spontaneous abortion. Results: Yolk sac was present in 140 cases (97.22%), and in 4 cases (2.78%), it was absent. Out of 140 cases, it was calcified in two cases and normal in 138. All the cases in which there was absence of yolk sac or calcified yolk sac resulted into spontaneous abortion. Conclusion: Accurate recognition of the normal and abnormal sonographic findings related to yolk sac can be used to anticipate the course of pregnancy which may be used as good tool in clinical practice to predict whether a pregnancy is going to have a good or a poor outcome.

Metastatic melanoma in a Saanen goat: clinical, ultrasonographic and anatomopathological aspects - case report

ABSTRACT This report describes clinical, ultrasonographic and anatomopathological findings in a case of metastatic melanoma in an adult Saanen goat. Clinically, the goat had apathy, an intra-abdominal palpable firm structure, and exophytic keratinized areas on the skin of the udder. Ultrasound revealed non-encapsulated oval structures, with heterogeneous echogenicity and marked central and peripheral vascularization, and hypoechoic hepatic multifocal to coalescent areas. In the udder, there were non-encapsulated oval structures with heterogeneous echogenicity and hyperechoic center surrounded by hypoechogenic tissue. Grossly, there were black multifocal to coalescent areas in the liver, as well as black nodules in mammary and mesenteric lymph nodes, uterus, spleen, and myocardium. Microscopically, multifocal melanocytic neoplastic proliferation was observed in the dermis and junction of the udder epidermis. Most of the neoplastic cells had cytoplasmic granules of melanin. In the liver there were areas of neoplastic tissue compressing the adjacent parenchyma, with central foci of necrosis, mild desmoplasia, and multifocal infiltration of malignant cells into the adjacent tissues. Similar findings were observed in the mammary and mesenteric lymph nodes, uterus, spleen, and myocardium, which characterized metastatic melanoma. Ultrasonography played a key role for establishing the diagnosis of a metastatic melanoma and helped establish a proper clinical management protocol.

Sonographic Detection of Accessory Adrenal Tissue in Neonates.

The purpose of this study was to describe the incidence and appearance of accessory adrenal tissue in neonates, as diagnosed by high-resolution sonography, and increase the awareness of this entity. We examined the adrenal glands in 153 neonates referred for renal and urinary tract sonography at our institution between January 2014 and January 2015. All kidneys and adrenal glands, except for ectopic kidneys, were scanned with the neonate prone and a linear array transducer with frequency of 11 or 14 MHz. In 9 neonates (5.9%), sonography showed a round, well-defined structure adjacent to the adrenal gland with a hyperechoic center and hypoechoic periphery, similar to the echogenicity of the normal adrenal medulla and cortex, respectively. The largest diameter of the structure measured 2.9 to 4.5 mm. On follow-up studies, which were available for 7 neonates, the structure was not evident, and the suprarenal area was normal. Accessory adrenal tissue can be identified in the suprarenal area in neonates with high-resolution sonography. Radiologists and sonographers caring for neonates should be aware of this finding and not confuse it with disease.

Primary hemangioendothelioma of liver; report of a case and review of literature

Abstract Hepatic epithelioid hemangioendothelioma (HEH) is an exceedingly rare tumor of vascular origin with unknown etiology and unpredictable natural course and malignant potential. The disease presents with myriad of vague symptoms and can be diagnosed by ultrasound, CT, and MRI. Target shaped hepatic lesions due to hyperechoic center and hypoechoic peripheral rim are the diagnostic ultrasonic features. Hepatic capsular retractions due to extensive fibrosis can be identified by CT and MRI. The lesions are usually hypointense on T1-weighted images and hyperintense on T2-weighted images. There is no consensus on treatment of hepatic epithelioid hemangioendothelioma, which ranges from hepatic resection, hepatectomy, liver transplantation, chemo- and radiotherapy, and thermoablation. This case report presents a 36-year-old female, incidentally diagnosed to have hepatic epithelioid hemangioendothelioma, which was treated by right hepatectomy and was attended by favorable outcome.

Lymph Nodes in Hidradenitis Suppurativa

Background: Hidradenitis suppurativa (HS) is an inflammatory disease, and yet palpable lymph nodes are rarely found. This may be due to lack of lymph node swelling or to the inability to palpate lymph node regions due to overlying disease. Ultrasound was used to identify and measure regional lymph nodes in HS patients. Methods: High-resolution ultrasound scanning was carried out with compact linear 15–7 MHz and linear 12–5 MHz probes in both axillae and inguinal regions following informed consent. Results: A total of 198 lymph nodes were identified in 6 HS patients in Hurley stage II and 4 in stage III, and 101 from regional control scans in healthy controls. All the lymph nodes in both HS patients and controls showed a normal oval shape, with a hypoechoic rim and a hyperechoic center, and all were located in the deep subcutaneous tissue. The overall mean lymph node number per region was not significantly different. The overall mean lymph node diameter was not significantly different, but in patients with Hurley stage III disease it was significantly increased (1.3 ± 0.4 cm, p = 0.03). Conclusion: Lymph node involvement only occurs with late-stage HS and may therefore reflect secondary infection rather than primary etiological involvement.

Late Abscess Formation Caused by Silk Suture Following Hysterectomy in a Female Dog

A 5-year-old female cross-breed dog was presented for a one-month history of lethargy, poor appetite and weight loss. A hysterectomy had been performed 2 years ago. Abdominal palpation revealed a mid-abdominal mass and haematological analysis showed leucocytosis with left shift. On abdominal radiographs, a 9 cm in diameter soft tissue opacity mass ventral to the colon and caudal to the left kidney was observed. The abdominal ultrasonography revealed a mass well circumscribed, with a hyperechoic capsule and hypoechoic center with echoic debris. The presumptive diagnosis was an abscess due to foreign body granuloma. Laparotomy was performed and a mass close to the left ovary was found. Adhesions and residues of the suture material were observed close to the right ovary and the uterine body stump. The mass, both ovaries and adhesions were removed. On cut section of the mass two cavities were observed. The small one contained three embedded silk suture residues. Histopathological examination confirmed the diagnosis of a chronic abscess caused by silk suture.

Suprapancreatic and periportal lymph nodes are normally larger than 1 cm by laparoscopic ultrasound evaluation.

Laparoscopic and endoscopic ultrasound is used to assess resectability of gastrointestinal malignancies. Lymph node size greater than 1 cm is a criterion used to identify suspicious nodes. We define size and echo characteristics of suprapancreatic and periportal nodes to determine if this criterion is reliable for suprapancreatic and periportal lymph nodes. A prospective study of 21 patients with nonacute gallbladder disease was performed. Each underwent laparoscopic cholecystectomy with intraoperative ultrasound. The suprapancreatic and periportal nodes were evaluated in a transverse and longitudinal axis. Length and width measurements were taken in both orientations. Length-to-width ratios were calculated. Shape and echo textures were characterized. The mean size of both nodes was greater than 1 cm in the transverse and longitudinal orientation. Two nodes were "round." Remaining nodes were "oblong." All nodes had a hyperechoic center with a hypoechoic rim. In suprapancreatic and periportal lymph nodes, size greater than 1 cm should not be used as criterion for malignancy.

Ultrasonographic findings of intestinal intussusception in seven cats

The medical records of seven cats with intestinal intussusception that were diagnosed by abdominal ultrasonography and exploratory laparotomy were reviewed. In transverse ultrasonographic sections the intussusception appeared as a target-like mass consisting of one, two or more hyperechoic and hypoechoic concentric rings surrounding a C-shaped, circular or non-specific shaped hyperechoic centre. Part of the intestine representing the inner intussusceptum, located close to the hyperechoic centre and surrounded by concentric rings, was also detected. In longitudinal sections the intussusception appeared as multiple hyperechoic and hypoechoic parallel lines in four cases and as an ovoid mass in three cases. In one case the ovoid mass had a ‘kidney’ configuration. Additional ultrasonographic findings associated with intestinal intussusception included an intestinal neoplasm in one cat. The results of the present study demonstrate that the ultrasonographic findings of intestinal intussusception in cats bear some similarities to those described in dogs and humans, are relatively consistent, and facilitate a specific diagnosis.

Radiographic and ultrasonographic features of retained surgical sponge in eight dogs.

The radiographic and ultrasonographic signs in eight dogs with a surgical or pathologic diagnosis of retained surgical sponge were reviewed. The most frequent previous surgery was ovariohysterectomy, either as an elective procedure or to treat pyometra. The median elapsed time between surgery and diagnosis of retained surgical sponge was 9.5 months (range 4 days to 38 months). Five dogs had a draining sinus; four had a palpable abdominal mass. Radiologic signs included localized, speckled or whirl-like gas lucency, abdominal mass, and non-focal soft tissue swelling. Survey radiography and sinography were considered diagnostic for retained surgical sponge in 4/7 (57%) and 3/5 (60%) dogs, respectively. The combined use of survey radiography and sinography enabled detection of 6/7 (86%) sponges. In each dog that had ultrasonography, a hypoechoic mass was found that had an irregular hyperechoic centre. The possibility of retained surgical sponge should be considered in animals with a history of previous surgery and a sinus or abdominal mass.

Laparoscopic ultrasonography of abdominal lymph nodes: correlation with pathologic findings.

The value of laparoscopic ultrasonographic criteria for distinguishing benign from malignant lymph nodes was assessed. The following criteria were evaluated in 41 lymph nodes: (1) long axis diameter, (2) short axis diameter, (3) long axis-short axis ratio, (4) nodal border delineation, (5) presence of hyperechoic hilar reflection, (6) echogenicity, and (7) inhomogeneity. Pathologic examination showed malignant infiltration in 11 lymph nodes and the absence of malignant infiltration in 30 lymph nodes. The presence of a hyperechoic center or a long axis-short axis ratio more than 2 suggested the absence of malignant infiltration, whereas inhomogeneity was suggestive of malignant infiltration. The other criteria did not seem useful in distinguishing benign from malignant lymph nodes.

Echo pattern of lymph nodes in colorectal cancer: an in vitro study.

Surgical specimens from 75 patients with colorectal cancer were examined within 15 min of removal with a 7.5 MHz linear-array transducer. The echo pattern of 139 lymph nodes was analysed to evaluate previous criteria of malignancy and to establish other possible criteria, which could be tested in vivo. The pathologist examined each node without knowledge of the sonographic finding. Malignant nodes were larger than benign nodes. Of 21 nodes less than 5 mm in diameter, 20 were benign. Round nodes were malignant more often (45/78) than ovoid nodes (6/61). A homogeneous echo pattern was associated with malignancy in 39 of 82 nodes in contrast to 12 of 57 with a heterogeneous pattern. Thirty-one nodes were ovoid as well as heterogeneous and all of these were benign. A hyperechoic centre was found in 14 nodes of which two were malignant. The highest predictive value for malignancy (59%) was obtained by combining the discriminative properties of shape, homogeneity and echogenicity.

Ultrasonic features of duodenal ulcer

Five cases of duodenal peptic ulcers studied by ultrasound are presented. In all 5 patients, a hyperechoic area in various shapes and sizes corresponding to ulcers in x-ray was identified adjacent to gallbladder and head of the pancreas. This hyperechoic center was surrounded by a 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.

Peridiverticulitis of the Appendix

In a 26-year-old man with perforating diverticulitis of the appendix ultrasonography demonstrated a "target lesion" with a hyperechoic center surrounded by a hypoechoic rim similar to the findings commonly seen in benign and malignant conditions of the gastrointestinal tract. This ultrasonographic appearance is quite different from the ultrasonic findings usual in acute appendicitis. We take this to be the first ultrasonic demonstration of appendiceal diverticulitis, and discuss the clinical features, ultrasonic differential diagnosis, and pathology of this condition.