ULTRASOUND DEVICE RULES OUT MAXILLARY SINUS FLUID in ACUTE RHINOSINUSITIS

New Method to Diagnose Sinusitis: Doppler Ultrasound

New Method to Diagnose Sinusitis Could Reduce Use of Antibiotics
October 6, 2011

Có một phương pháp chẩn đoán viêm xoang mới trong một luận văn vừa thông qua tại Lund University. Các kết quả cung cấp khả năng làm giảm dùng kháng sinh và phí tổn điều trị cho xã hội.

Viêm mũi xoang là tiến trình viêm nhiễm niêm mạc mũi và một hay nhiều xoang cạnh mũi. Mục tiêu công trình nhằm khảo sát mức độ viêm mũi xoang ảnh hưởng đến chất lượng sống có liên quan đến sức khoẻ (health-related quality of life, HRQOL), và nhằm xác định làm thế nào hoàn hiện chẩn đoán bệnh này bằng cách sử dụng siêu âm Doppler.

H.3: Siêu âm được dùng phát hiện dịch trong xoang hàm và xoang trán. Khi xoang hàm có dịch sẽ có xung siêu âm với đỉnh =4-5cm trên trục x của màn hiển thị dụng cụ siêu âm.

H.6: Dụng cụ siêu âm Doppler thiết kế để phân biệt serous với mucopurulent sinus secretion. Luồng chảy âm được phát hiện (và kết quả là đo được độ lệch Doppler) trong dịch xoang là dấu hiệu của dịch tiết không mủ (non-purulent secretions).

H.7: Thiết bị dùng xác định tốc độ và sự giảm âm trong một mẫu dịch. Hình trình bày hộp dùng để đo với đầu dò siêu âm.

HRQOL của 207 bệnh nhân được phân làm 3 nhóm, một nhóm là viêm mũi xoang cấp tái phát, và hai nhóm viêm mũi xoang mạn có polyp mũi hoặc không, được đánh giá bằng 22 Sinonasal Outcome Test (SNOT-22), 36-item short-form questionnaire (SF-36), Hospital Anxiety and Depression (HAD) scale và total visual analogue scale (VAS). HRQOL của những bệnh nhân này giảm có ý nghĩa so với giá trị bình thường. Giữa 3 nhóm, HRQOL scoring có những khác biệt nhau có ý nghĩa. Nghiên cứu cohort (thuần tập) này ghi nhận có 8-14 ngày bỏ việc mỗi năm vì vấn đề xoang. SNOT-22 và total VAS biểu hiện là các biện pháp có tác động thích hợp trong các trường hợp viêm mũi xoang trong cộng đồng Thuỵ điển.

Không thể phân biệt serous sinus fluid (có độ nhớt thấp) với mucopurulent sinus secretions (có độ nhớt cao) bằng CT hay siêu âm. Tuy nhiên, việc xác định không xâm lấn thành phần chất tiết của xoang thường có vi khuẩn trong dịch mủ nhày của viêm mũi xoang là có giá trị.

Để tăng cường chẩn đoán cho những bệnh nhân này, phải phát triển thêm kỹ thuật siêu âm. Trong luận văn, có thể gây ra luồng chảy âm (acoustic streaming) trong mô hình xoang (sinus model), và qua đó đặc tính âm của dịch được xác định bằng siêu âm Doppler. Tần số siêu âm thích hợp là 5MHz, điều này rất quan trọng. Nếu tần số quá cao, xương sẽ hấp thu siêu âm hoàn toàn và không thể xuyên thấu vào xoang. Nếu tần số quá thấp, chuyển đổi năng lượng vào dịch xoang không đáng kể nên sẽ không phát hiện được luồng chảy. Kích thước xoang hàm và xoang trán được khảo sát bằng hình CT để thiết kế dụng cụ Doppler có hiệu quả lâm sàng. Siêu âm Doppler có thể phân biệt serous sinus fluid với mucopurulent sinus secretion, mà bệnh nhân không bị ảnh hưởng do tăng nhiệt độ.



SIÊU ÂM KHÁM KHỚP THÁI DƯƠNG-HÀM

The HR-US investigation (Fig. 1) was performed by an experienced oral and maxillofacial surgeon with the transducer overlying the zygomatic arch in a vertical position with the mouth closed and at maximum mouth opening. The position of the disc was detected in the closed mouth position. The patient was then asked to open his mouth to the maximum mouth opening position when the position of the disc was detected again.

The HR-US investigation was performed regarding the following criteria: destructive changes (Fig. 2); effusion; disc dislocation (Fig. 3) at closed mouth and maximum mouth opening positions; and disc dislocation with reduction (disc dislocation in closed mouth position and no disc dislocation in maximum mouth opening position).

Discussion

Temporomandibular disease (TMD) in chronic polyarthritis (CP) patients is reported in the literature with a variation of 5–90%, depending on the investigated parameters. The imaging diagnosis of TMD is difficult because panoramic radiographs show TMD only in a late stage, whilst intervention is required at an early stage of the disease. MRI is still the gold standard in the diagnosis of TMD but availability and high costs do not allow the use of MRI as a screening method. A clinical usable, cheap and widely available diagnostic imaging tool is essential to support the clinical diagnosis of TMD. US investigation of the TMJ has been described as insufficient using 7.5–10 MHz transducers. The development of HR transducers showed, that using these transducers, effusion, disc dislocation, and destructive changes could be detected with high sensitivity, specificity, diagnostic accuracy, and positive and negative predictive value compared with the current gold standard of MRI. The use of HR-US is a cheap and widely available alternative imaging method to MRI, especially for screening, because of its low cost. The technique is limited to specialized centres because of a long learning curve to achieve satisfactory diagnostic accuracy. Referring to the diagnostic value of HR-US the authors waived a control group in the current study.

The aim of this study was to investigate, whether pathological HR-US findings correlate with pathological clinical findings such as clicking, crepitation, pain and closed lock. The use of these parameters in the current investigation seems to simplify the TMJ investigation, but these parameters were used because they can be detected easily by the rheumatologist during routine examination.

Regarding the clinical findings, 23 of 40 patients showed pathological changes of the TMJ. 9 patients (23%) reported a closed-lock in the past, which is one of the severest clinical findings. If the joints are observed separately, in 10% of patients, actual pain and pain on palpation was found. The highest percentage of TMJ pathology was found regarding the TMJ sounds, such as clicking and crepitation.

The comparison of these results with previous studies shows that the cohort of patients investigated is representative. Compared with previous US investigation of TMJ in chronic polyarthritis, TMJ crepitation studies regarding the investigation of asymptomatic volunteers, HR-US investigation of the TMJ showed a much higher percentage of pathological findings. The HR-US investigation showed destructive changes in 34 patients (85%),which leads to a high number of cases of chronic TMD. As a result of chronic TMD, dislocated discs were diagnosed by HR-US with a maximum percentage of 40%. HR-US investigation showed TMJ effusion in 7 (18%) joints, which leads to the interpretation of acute TMD. These results are confirmed by the significant correlation between effusion and pain on palpation of the masticatory muscles.

Regarding the statistical correlations between the HR-US investigation and the clinical findings of the TMD, a significant correlation between TMJ sounds (clicking and crepitation) and destructive changes and disc dislocation in the closed and/or maximum mouth opening position was determined. The correlation between any TMJ pathology (summarized) and destructive changes and TMJ effusion leads to the interpretation that HR-US could detect chronic and acute TMD.

Further studies with larger cohorts of patients are required to confirm the current results. The results of the current study suggest that CP patients should be referred to a dentist and/or a TMJ specialist. US is a well-known diagnostic imaging tool in rheumatology. Even if HR-US of the TMJ requires a long learning curve, training in HR-US for rheumatologists and/or radiologists should be instituted so the method can become widely available as an imaging tool.

Hepatic Vascular Shunts

Introduction

Intrahepatic vascular shunts are common; all intrahepatic vessels are associated with the formation of shunts. These include arterioportal (AP), portosystemic and arteriosystemic venous shunts. Rarely, systemic venous (i.e. hepatic vein to hepatic vein) shunts and portal-to-portal communications are seen [1]. The unique dual blood supply of the liver (approximately 75% portal venous and 25% arterial) means there is a compensatory relationship between the two sources. When vascular compromise occurs, it causes a macroscopic opening of the shunts between the hepatic arteries, the portal veins and the hepatic veins through physiological anastomoses, which become abnormally enlarged [1-3].

Embryology

In the fifth week of intrauterine life, there are three major paired veins in the abdomen: the vitelline or omphalomesenteric veins, the umbilical veins and the cardinal veins. The vitelline veins form the hepatic sinusoids. The left vitelline vein subsequently involutes and the blood is diverted into the right vitelline vein, which enlarges and forms the hepatocardiac portion of the inferior vena cava (IVC). Derivatives of the vitelline veins also form the hepatic and portal vein. The entire right umbilical vein and a portion of the left umbilical vein also degenerate. The persistent portion of the left umbilical vein connects to the right vitelline vein via the ductus venosus (Figure 1). The hepatic artery arises from the aorta and follows the mesentery [4,5].

In antenatal circulation, oxygenated blood from the placenta returns to the foetus via the umbilical vein and flows through the ductus venosus into the IVC (Figure 2a). At birth, there is functional closure of the umbilical arteries, veins and the ductus venosus. Following atrophy, these form the medial umbilical ligaments, the ligamentum teres and the ligamentum venosum, respectively. Post-natal anatomy consists of inflow into the liver through the hepatic artery and portal vein, with the outflow through the hepatic veins (Figure 2b) [5].

There is potential for intrahepatic shunts to develop when the ductus venosus remains patent, from failure of right upper vitelline vein regression, from a varix of the portal vein connecting to the hepatic/systemic venous circulation, from focal persistence of the most superior aspect of the vitelline veins or from arteriovenous malformations or neoplasms [6,7].

Classification

The hepatic vascular shunts can be divided into AP, portosystemic, arteriosystemic, systemic-venous, and portal-to-portal shunts.

Imaging features of hepatic vascular shunts

Arterioportal shunts
AP shunts are seen in congenital vascular malformations, including those identified in patients with hereditary haemorrhagic telangiectasia (HHT), as well as in benign and malignant hepatic neoplasms, cirrhosis, tumour thrombus and trauma. On colour Doppler imaging, these shunts display high-velocity, low-resistance arterial waveforms with arterialised portal venous flow.

HHT, or Osler-Weber-Rendu (OWR) syndrome, is an autosomal dominant disorder known to involve virtually every organ of the body, with hepatic involvement in 8–31% of cases. Hepatic manifestations include AP shunts (Figure 3), arteriosystemic shunts (most common type), portovenous shunts, telangiectases, large confluent vascular masses, perfusion abnormalities, fibrosis and cirrhosis [9,10]. Patients with symptomatic liver disease (high-output liver failure or portal hypertension) and atypical cirrhosis ultimately require transplantation [10]. Among hepatic tumours, AP shunts are most commonly identified in patients with hepatocellular carcinoma (HCC). They are also commonly seen in cirrhosis, especially after a portocaval shunt operation [4,8]. These shunts are typically wedge-shaped, with or without internal linear branching structures in the arterial phase, and are iso- to slightly hyperattenuating during the portal venous phase. However, a follow-up radiological study may be required to exclude the possibility of a coexistent tumour [11]. Tumour thrombi are seen most commonly in patients with HCC (Figure 4) and to a lesser extent in patients with cholangiocarcinoma or metastases, and also cause AP shunting. Trauma-related AP shunts may occur secondary to penetrating trauma, and can be caused by a liver biopsy (Figure 5) or by percutaneous biliary catheterisation. Radiological imaging-guided intervention, such as embolisation, is performed if there is rapid development of life-threatening portal hypertension or high-output cardiac failure. If embolisation fails, surgery is often necessary [2,8].

Portosystemic venous shunts
Portosystemic venous (PV) shunts are relatively rare, and are seen between a portal venous branch and a hepatic vein or the IVC. Postulated congenital causes include persistence of a communication between the vitelline veins and the right horn of the sinus venosus or rupture of a portal vein aneurysm into a hepatic vein [4,12,13]. Park et al [13] have described four morphological types of portosystemic shunts. Type I shunt, the most common type, is a single large shunt connecting the right portal vein to the IVC (Figure 6). Type II shunt is either single or multiple, and communicates between the portal and hepatic veins in one hepatic segment (Figure 7). Type III shunt is a small connection between a peripheral portal and hepatic vein through an aneurismal varix (Figure 8). Type IV shunts are multiple communications between the peripheral portal and hepatic veins, and are seen diffusely in both lobes (Figure 9). A patent ductus venosum connecting the left portal vein to the IVC could be considered the fifth type of portosystemic shunt (Figure 10) [4]. Embolisation or surgery is performed if the shunt is symptomatic.

Acquired causes of PV shunts include portal hypertension with or without associated HCC, iatrogenic (from transjugular intrahepatic portosystemic shunt, TIPS; Figure 11), surgical portocaval shunt (Figure 12), surgical mesentericocaval shunt and trauma [14]. PV shunts appear as anechoic tubular cystic channels on greyscale sonography, with a pulsatile spectral Doppler waveform in the portal and splenic veins [4,15]. CT and MRI can confirm the diagnosis [4].

Arteriosystemic venous shunts
Arteriosystemic venous (AV) shunts are communications between the hepatic artery and the hepatic veins. These can be seen in vascular malformations such as HHT, as well as in benign and malignant liver lesions including infantile haemangioendothelioma, haemangioma and HCC [1]. Infantile haemangioendothelioma (Figure 13) usually manifests clinically before 6 months of age with high-output congestive failure, hepatomegaly, anaemia, thrombocytopenia, respiratory distress, haemorrhage or jaundice. Haemangiomas in the skin and associated organs (haemangiomatosis) are also commonly identified. When AV shunting is present, high-peak Doppler shifts and a low resistive index in the feeding arteries may be seen, as well as hyperpulsatility of the portal vein and a pulsatile pattern in the draining veins. There is also aortic tapering at the branching point of the coeliac artery. Asymptomatic patients are closely followed up without treatment. Standard treatment for infantile haemangioendothelioma is corticosteroids. If there is no clinical improvement, interferon treatment should be attempted. Embolisation or surgery is reserved for patients in whom congestive heart failure remains even after a reasonable trial of medical therapy. Chemotherapy and radiation therapy have also been used [4].

Systemic-to-systemic venous shunts
Systemic-to-systemic shunts are more often seen in patients with chronic hepatic venous congestion or Budd-Chiari syndrome. When Budd-Chiari syndrome occurs, there is obstruction of the hepatic venous outflow in the absence of right heart failure or constrictive pericarditis, and patients present with hepatomegaly, ascites and abdominal pain. Hepatic venous shunts (Figure 14) are a specific diagnostic criterion for the diagnosis. These are either intrahepatic, which communicate with systemic vessels via subcapsular collaterals, or from an occluded hepatic vein to a non-occluded hepatic vein or to the caudate lobe veins. Rarely, shunts are seen from the hepatic veins to the suprahepatic IVC close to the right atrium. Therapeutic interventions include thrombolytic therapy, angioplasty with or without stenting, TIPS, surgical shunting and liver transplantation [16]. Systemic-to-systemic venous shunts have also been identified in patients with HHT, and in HCC following tumour extension into the hepatic veins [1].

Portal-to-portal venous shunts
Intrahepatic portal-to-portal venous (PPV) shunts are rare, but may be seen in cirrhosis. Recognition of these shunts is important as they can mimic HCC [17]. Extrahepatic PPV collaterals (Figure 15) and portal vein cavernomas are commonly seen with portal vein thrombosis [1].

Conclusion

Congenital and acquired hepatic vascular shunts are frequently seen on cross-sectional imaging examinations, particularly on sonography and MDCT. Awareness of the various types of hepatic vascular shunts can assist the radiologist in establishing an accurate diagnosis and in guiding appropriate patient management.

Subcentimeter Thyroid Nodules

Abstract

OBJECTIVE. The purpose of this study is to examine subcentimeter thyroid nodules to determine their rate of malignancy, the accuracy of various ultrasound features in prediction of malignancy, and the utility of ultrasound-guided biopsy of these nodules.

MATERIALS AND METHODS. Included in this retrospective study were 104 patients in whom 108 thyroid nodules smaller than 1 cm had been biopsied. Diagnostic ultrasound examinations were reviewed, and nodules were evaluated for the following ultrasound features: internal echogenicity, margins, height-to-width ratio, presence of calcifications, posterior acoustic features, solid-to-cystic ratio, presence of a halo, and color Doppler characteristics. In addition, a subjective assessment of level of suspicion was assigned to each nodule. Each feature was correlated with the pathologic results to determine the accuracy of the feature for predicting malignancy.

RESULTS. Adequate cytologic specimens were obtained in 97 of the 108 subcentimeter biopsies (90%) performed. The average size of malignant nodules was significantly smaller than the average size of benign nodules (6.4 ± 2.1 vs 7.7 ± 1.4 mm, p = 0.041). The rate of carcinoma among nodules with a final diagnosis was 19% (16/85). The most accurate features significantly associated with malignancy were posterior acoustic shadowing (87%), many diffuse calcifications (82%), rim calcifications (81%), and taller than wide shape (79%). The subjective level of suspicion correlated well with the presence of malignancy (76%).

CONCLUSION. Subcentimeter nodules are significantly associated with the risk of malignancy and can be accurately and safely biopsied with a very high diagnostic rate. Certain ultrasound features can be used to accurately stratify risk of malignancy, although no single feature replaces the clinician’s overall impression.



Screening for Carpal Tunnel Syndrome Using Sonography

Abstract
 
Objectives—The use of sonography in musculoskeletal research and clinical applications is increasing; however, measurement techniques for diagnosing carpal tunnel syndrome with sonography continue to be inconsistent. Novel methods of measurement using internal comparisons to identify swelling of the median nerve require investigation and comparison to currently used techniques.


Methods—The flattening ratio of the median nerve, bowing of the flexor retinaculum, and cross-sectional area of the median nerve were collected in the forearm, at the radiocarpal joint, and at the level of the pisiform in both symptomatic patients and asymptomatic control participants. Electrodiagnostic testing was completed in symptomatic patients as a diagnostic standard.

Results—Median nerve measurements were collected from 166 wrists of symptomatic and asymptomatic participants. The flattening ratio did not show any correlation to electrodiagnostic testing and was identical between both symptomatic and asymptomatic participants. Moderate to strong correlations were noted between electrodiagnostic testing results and sonographic measurements of the cross-sectional area at the pisiform, retinacular bowing, and both the ratio and change of the cross-sectional area between the forearm and pisiform. The area under the curve was large for all receiver operating characteristic curves for each measurement (0.759–0.899), and sensitivity was high (80.4%–82.4%).
---------------------------------
Measurements of the anteroposterior height (millimeters) and mediolateral width (millimeters) were taken at each of the 3 locations from the inside edge of the echogenic borders of the median nerve. The cross-sectional area (square millimeters) was obtained by a direct trace along the inner rim of the echogenic border of the nerve in each location (Figure 1). The height of the retinacular bulge was measured as the perpendicular distance from a line connecting the insertion points on the trapezium and hook of the hamate to the anterior-most point of the flexor retinaculum (Figure 2).
The flattening ratio was calculated by dividing the width by the height of the nerve in each of the locations.
The cross-sectional area in the forearm was used as an internal reference for each participant. Cross-sectional area change scores were calculated as the absolute difference of the cross-sectional area at the distal radius and pisiform from the cross-sectional area in the forearm. The cross-sectional area ratio was calculated for each participant as the cross-sectional area at the distal radius and pisiform each divided by the cross-sectional area in the forearm.

Without reducing the image resolution, images were magnified to improve the precision of measurements along the inner echogenic border of the median nerve. Each measurement was repeated 5 times; the highest and lowest measurements were excluded; and the remaining 3 measurements were averaged.
-------------------------------------
Conclusions—Measurement of swelling through a ratio or absolute change had similar diagnostic accuracy as individual measurement of the cross-sectional area within the carpal tunnel. These measures may be useful for improving accuracy in more diverse clinical populations. Further refinement of protocols to identify the largest cross-sectional area within the carpal tunnel region and statistical methods to analyze clustered, multilevel outcome data are recommended to improve diagnostics.

Focal Liver Lesions (FLL) with Acoustic Radiation Force Impulse (ARFI) Elastometry

Characterization of focal liver lesions (FLL) with acoustic radiation force impulse (ARFI) elastometry, Heide R, Strobel D, Bernatik T, Goertz RS.
Ultraschall Med. 2010 Aug;31(4):405-9. Epub 2010 Jul 22.

Abstract

PURPOSE:

The technology of acoustic radiation force impulse (ARFI) represents an innovative method for the quantification of tissue elasticity. The aim of this prospective pilot study was to evaluate the role of ARFI elastometry of focal liver lesions (FLL) and the surrounding liver parenchyma.

MATERIALS AND METHODS:

All patients with unclear FLL in B-mode ultrasound were assigned to ARFI elastometry (m/sec). Measurement sites were located within the FLL, in the peritumoral tissue and in hepatic segment VIII (intercostal approach). Histology and CEUS served as the reference for the characterization of the lesions.

RESULTS:

A total of 81 patients were enrolled, of whom 62 patients (39 females, 23 males; mean age 54 years) had FLL measurable by means of ARFI. The lesions were: 38 benign (61 %) and 24 malignant FLL (39 %). The ARFI elastometric values of the FLL differed significantly from those of the liver parenchyma (p < 0.001). Elastometry of benign lesions and of malignant tumors showed statistically comparable results (p = 0.28). The lowest ARFI values were observed in focal fatty sparing and the highest in HCC. Only focal fatty sparing and HCC showed negative differences between FLL and peritumoral tissue or liver parenchyma. In 23 % of the hepatic lesions, no reliable quantitative ARFI results were obtainable due to false, inconsistent or technically failed measurements.

CONCLUSION:

FLL vary in ARFI elastometry. However, high ARFI values occur in benign as well as in malignant lesions and do not permit differentiation between them.
------------------------------------

VON MEYENBURG COMPLEX  TRONG GAN và TẠO HÌNH ARFI

JASMINE THANH XUÂN, PHẠM THỊ THANH XUÂN, LÊ THANH LIÊM, NGUYỄN THIỆN HÙNG, Trung tâm Y khoa MEDIC Hoà Hảo, Thành phố Hồ Chí Minh, Việt nam.


Chúng tôi trình bày một trường hợp phức hợp von Meyenburg hay hamartoma đường mật ở một phụ nữ 29 tuổi không có triệu chứng lâm sàng, được phát hiện tình cờ khi khám siêu âm check-up. Đây là ca Von Meyenburg complex đầu tiên được khảo sát bằng siêu âm đàn hồi ARFI với máy ACUSON S2000 tại trung tâm Y khoa MEDIC Hoà Hảo, Việt nam.

Hình 1: Trên nền gan biến dạng như viêm gan mạn, có nhiều nốt echo dày và kém rải rác, có comet tail artifact và không có bóng lưng. Không tìm thấy nang gan nào trong cả 2 thuỳ. Kỹ thuật eSie Touch, với đầu dò curve 4C1 cho thấy nhu mô gan không đồng dạng, mã màu đỏ và vàng cam (cứng) với quality factor (QF)=65.

Hình 2-3: Các nốt echo dày, là các chỗ giãn thành nang chứa chất keo của đường mật, có tốc độ sóng biến dạng trung bình (SWV)= 1,22+/-0,03 m/s của dời chỗ ARFI ở độ sâu trung bình 4cm trong khi nền gan  có SWV=0,95+/-0,06 m/s với virtual tissue quantification (VTQ).

Hình 4: Với đầu dò linear 9L4, kỹ thuật virtual tissue imaging (VTI) trình bày các nốt echo dày ở hình B-mode, có darker color hơn mô gan, kích thước =1,9-2,1-2,2mm. Bờ gan không phẳng mịn như hình B-mode mà dày không đều [từ 1,2-1,8-1,9mm] và sậm màu hơn mô gan.

Hình 5: Dùng tiện ích vẽ tự động và tính area ratio của máy, mỗi nốt ( chỗ giãn đường mật) có diện tích lớn hơn hình B-mode= 0,22-0,42mm2 có thể do desmoplastic reaction xung quanh tổn thương.

Theo chúng tôi biết, chưa có báo cáo siêu âm đàn hồi nào về hamartoma đường mật (von Meyenburg complex).

-------------------------------------------------
Sonographic Features of Biliary Hamartomas With Histopathologic Correlation, B. Keegan Markhardt, Deborah J. Rubens, Jiaoti Huang, Vikram S. Dogra, J Ultrasound Med 2006; 25:1631–1633.

Biliary hamartomas (BH) are uncommon benign biliary malformations composed of disorganized bile ducts and fibrocollagenous stroma. Biliary hamartomas are associated with autosomal dominant polycystic kidney disease (ADPKD), polycystic liver disease (PLD), Caroli disease, and congenital hepatic fibrosis. The major clinical importance of BH is that they may be misdiagnosed as multiple liver metastases, microabscesses, lymphoma, leukemia, Candida albicans, or extrapulmonary Pneumocystis carinii infection at initial imaging. In patients with ADPKD, these may be mistaken for small cysts, cirrhotic changes, or one of these more ominous diseases. The following report illustrates the distinguishing sonographic features of BH in a patient with ADPKD with histopathologic correlation.

Discussion

Biliary hamartomas were first described by von Meyenburg in 1918 and are referred to as von Meyenburg complexes. Biliary hamartomas are uncommon benign biliary malformations composed of groups of dilated intrahepatic bile ducts embedded within a dense collagenous stroma. They usually measure less than 5 mm
and are typically multiple and scattered throughout the liver.  They are located within and at the edges of portal tracts and are not connected with the biliary system. Aggregations of BH may appear as larger solitary lesions on imaging.
Biliary hamartomas are detected incidentally at autopsy in 0.6% to 5.6% of cases. Biliary hamartomas are thought to develop from interrupted remodeling of the ductal plates during the late phase of embryologic development of the intrahepatic bile ducts.  Ductal plate malformation is involved in the genesis of BH, congenital hepatic fibrosis, and liver cysts in ADPKD, PLD, and Caroli disease. Moreover, BH are associated with each of these disorders,and there is evidence that cysts in both ADPKD and PLD arise from dilatation of the ductal plate malformation structures of BH.

On sonography, BH have been described as innumerable tiny hypoechoic or hyperechoic foci measuring less than 10 mm and distributed uniformly throughout the liver, and they may have a comet tail artifact.  Differences in echogenicity may be due to the size of the dilated bile duct component, which, at a certain size, would behave like other microcystic structures and show echogenicity. Below this size, their complex internal structure might attenuate the echo signal.

Figure 2. Low-power histologic specimen of a bile duct hamartoma. The lesion is lobulated with irregular, angulated bile ducts (large arrows) present in the background of fibrotic stroma (asterisk). The epithelial cells are single layered, flattened, or cuboidal (small arrow). Bile is shown in some ducts. The stroma contains neutrophils and histiocytes (hematoxylin-eosin, original magnification × 20).


On computed tomography, BH are depicted as multiple round, small hypoattenuating and nonenhancing areas distributed throughout the liver without a distinctive distribution pattern.
On MRI, BH are described as hypointense on T1-weighted images and hyperintense on T2-weighted images. On heavily T2-weighted images with a longer echo time, the signal intensity of the lesions remains high, allowing differentiation from liver metastasis.
Computed tomography and MRI did not help distinguish BH from small cysts associated with ADPKD.

The major clinical importance of BH is the propensity for misdiagnoses as multiple metastases, microabscesses, C albicans, and extrapulmonary P carinii infections. Metastases may be hypoechoic (eg, lymphoma) or hyperechoic (eg,colon and breast carcinoma). However, liver metastases are typically larger and variable in size and distribution, whereas BH are small and uniform in size and distribution.  Pyogenic microabscesses may appear as multiple widely scattered lesions similar in distribution to fungal microabscesses in immunosuppressed patients. A diffuse miliary pattern of pyogenic microabscesses may be seen in staphylococcal septicemia. Sonography may show either discrete hypoechoic nodules or poorly defined areas of distorted hepatic echogenicity with little or no enhancement through transmission. Sonographic imaging of patients with candidal infection may reveal lesions with alternating rings of hyperechogenicity and hypoechogenicity; however, a pattern of uniformly hypoechoic nodules is most common. Candida infection presenting as multiple echogenic foci may be mistaken for BH; however, these candidal foci show variable degrees of posterior acoustic shadowing, and this pattern occurs in later stages of infection, generally indicating early resolution.  In a patient with acquired immunodeficiency syndrome, extrapulmonary P carinii may present as numerous tiny hyperechoic foci in the liver,  which are similar to the appearance of BH.

In summary, whereas several acquired diseases may have an appearance similar to that of BH, in the context of ADPKD, BH should be considered high in the differential diagnosis of numerous tiny echogenic liver foci on sonography. Additionally, BH should be considered in the differential diagnosis of numerous tiny echogenic liver foci in PLD, congenital hepatic fibrosis, and Caroli disease.

Is ARFI image superior to B-mode image ?

Is ARFI image superior to B-mode image ?

Theo y văn, hình ARFI trong VTI giúp đánh giá tổn thương khu trú dễ hơn hình B-mode quy ước về:

- boundary definition

- echo contrast hơn mô lành, mô xơ hoá / mô ác tính (1)

Đối với tổn thương dạng nang (cystic) ở vú, hình ARFI có bright color và không đo được tốc độ sóng biến dạng (shear wave velocity, SWV) của dời chỗ ARFI (V= XX.Xm/s có nghĩa là nhỏ hơn 0m/s) (3) vì sóng biến dạng, khác với sóng siêu âm truyền theo chiều dọc, không truyền qua được chất dịch (và khí).

Đối với tổn thương đặc lành và ác tính, hình ARFI của HCC có 3 kiểu bright (mềm), same color, darker (cứng) khi so với mô nền. Trong lô nghiên cứu của Hee-Jin Kwon và cs (2011) ở HCC trước và sau khi đốt nhiệt cao tần (radiofrequency ablation, RFA) có dạng: trước RFA, u thường cứng với nhiều mức độ, sau RFA u thường darker và không đo được SWV. U tái phát sau RFA thường brighter (mềm hơn), và có đường viền rõ không như hình B-mode, giúp RFA lần hai cho u HCC tái phát (2).

Về tổn thương lành và ác tính ở vú, hình ARFI ở VTI thường darker so với mô vú xung quanh, và lớn hơn hình B-mode tương ứng, với area ratio (do máy tính) lớn hơn 2.0 nếu ác tính và SWV cao. Trong trường hợp u lành tính, area ratio nhỏ hơn 1.2, tuy u lành vẫn darker mô vú xung quanh (3), và SWV thấp hơn ngưỡng.

Vậy, u lành thường có hình ARFI darker hơn mô nền với SWV dưới giá trị ngưỡng, và không to hơn hình B-mode, trong khi u ác tính có hình ARFI darker, to hơn hình B-mode và SWV cao.

Qua 3 bài báo, đây chỉ là thu hoạch cá nhân ban đầu.

Về tạo hình ARFI trong viêm ruột thừa và viêm túi thừa đại tràng:


Trong viêm túi thừa đại tràng, đại tràng và túi thừa viêm và mô mỡ viêm tạo thành một khối có độ cứng hỗn hợp với các vùng mềm (bright color) và cứng (dark color) xen lẫn. Fecolith khó phân biệt, lẫn trong vùng bright color nên có vẻ không cứng.

Trong viêm ruột dư cấp hình ảnh ARFI của ruột thừa viêm và mô mỡ viêm tách biệt rõ. Mô mỡ viêm có bright color (mềm) trong khi toàn bộ ruột thừa viêm có dark color (cứng). Nếu như vách ruột thừa viêm luôn cứng (dark), lòng chứa dịch có bright color với độ cứng kém hơn mô mỡ viêm. Kích thước ruột thừa viêm ở hình ARFI luôn lớn hơn hình B-mode.

Tốc độ đàn hồi vách ruột thừa viêm nhỏ hơn 2m/s.

VTI hình cắt ngang

VTI hình cắt dọc

Tài liệu tham khảo:
1. In vivo visualization of abdominal malignancies with acoustic radiation force elastography, B J Fahey, R C Nelson, D P Bradway, S J Hsu, D M Dumont and G E Trahey, Physics in Medicine and Biology Volume 53 Number 1.
2. Acoustic radiation force impulse elastography for hepatocellular carcinoma-associated radiofrequency ablation, Hee-Jin Kwon, Myong-Jin Kang, Jin-Han Cho, Jong-Young Oh, Kyung-Jin Nam, Sang-Yeong Han, Sung Wook LeeWorld J Gastroenterol 2011 April 14; 17(14): 1874-1878.
3. PRELIMINARY RESULTS OF ACOUSTIC RADIATION FORCE IMPULSE (ARFI) ULTRASOUND IMAGING OF BREAST LESIONS, WEI MENG, GUANGCHEN ZHANG, CHANGJUN WU, GUOZHU WU, YAN SONG, and ZHAOLING LU, Ultrasound in Med. & Biol., Vol. 37, No. 9, pp. 1436–1443, 2011.