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Thứ Hai, 31 tháng 3, 2014
Vector Tissue Doppler Ultrasound Effective In Imaging Muscle, Tendon Motion
Scientists have developed a new approach that utilizes a Doppler ultrasound for quantifying muscle kinematics. The new technology, which has been designed to image muscle and tendon motion during dynamic tasks, can provide a complementary methodological tool for biomechanical studies in a clinical or laboratory setting.
Injured and painful joints feature complicated dynamics the understanding of which can help clinicians figure out how to address a variety of conditions. To visualize the processes involved in muscle and tendon dynamic tasks, the patient has to be imaged while using the injured joint.
The investigators have developed an innovative vector tissue Doppler imaging (vTDI) technique that can be used to measure musculoskeletal contraction velocity, strain, and strain rate with submillisecond temporal resolution during dynamic activities using ultrasound. The researchers from George Mason University (Fairfax, VA, USA; www.gmu.edu) have devised the new technology that uses existing modalities to provide a comprehensive picture as to how the musculoskeletal parts of the leg function.
Little white balls are fixed to specific points all over the patient’s body and a Doppler ultrasound probe is attached to the leg. The patient is then asked to perform a number of tasks while the ultrasound is recording and cameras monitor the balls to determine exactly how the individual is moving. Fusing the two modalities together provides a new ability to optimize the effectiveness of biomechanical studies. Moreover, other techniques, such as electromyography (EMG), can be used in conjunction to gain additional data.
The study’s findings were published in an open access article with a video in September 2013 in the journal JoVE. The aim of this early study was to investigate the repeatability and potential applicability of the vTDI technique in measuring musculoskeletal velocities during a drop-landing task,in healthy subjects.
The vTDI measurements can be performed concurrently with other biomechanical techniques, such as three-dimensional (3D)motion capture for joint kinematics and kinetics, EMG for timing of muscle activation and force plates for ground reaction force.
Integration of these complementary techniques could lead to a better understanding of dynamic muscle function and dysfunction underlying the pathogenesis and pathophysiology of musculoskeletal disorders.
Diagnostic ultrasound can enable direct imaging of muscle and tendons in real time, and therefore is an attractive alternative for measuring musculoskeletal dynamics and function during ADL.
Ultrasound-based quantitative measures of muscle morphology and architecture, such as muscle thickness, length, width, cross-sectional area (CSA), fiber pennation angle and fascicle length have been widely used. Image-processing methods have recently been employed to assess and quantify these quantitative measures during dynamic tasks. These advances have enabled a new methodological approach to understanding in vivo muscle function. However, these methods have primarily relied on using conventional grayscale (or B-mode) ultrasound imaging, and therefore have not fully exploited the possibilities of ultrasound to measure tissue velocities, strain, and strain rate using Doppler principles, that have been shown to be valuable in evaluating cardiac muscle function.
The vTDI technique can make measurements of muscles and tendons during highly dynamic tasks (e.g., drop-landing, gait) at high frame rates.
The investigators have implemented this method on a commercially available ultrasound system with a research interface, enabling this study to bemade in a clinical setting.
Vector TDI is based on estimating the resultant velocity vector from Doppler velocity measurements taken from two or more independent directions. An ultrasound system with a research interface was used for developing vTDI. The research interface allowed low-level beam forming and pulse sequence control using a software development kit (SDK). A 5–14 MHz linear array transducer, consisting of 128 transducer elements and with a 38-mm field-of-view was used. The research interface was employed to split the array transducer into two transmit and receive apertures and steer the receive beams by 15° with respect to the normal. The transmit beam was focused in the region of interest (e.g., muscle belly).
Transmit and receive apertures were set to 32 elements.
Image: Researchers have put together a system that uses existing technologies to give a detailed view of how the musculoskeletal components of the leg function (Photo courtesy of George Mason University).
Thứ Tư, 26 tháng 3, 2014
VTI on ARFI: A NEW TECHNIQUE for BENIGN and MALIGNANT THYROID NODULES
Abstract
Objectives—Acoustic radiation force impulse elastography is a newly developed ultrasound elasticity imaging technique that included both Virtual Touch tissue quantification and Virtual Touch tissue imaging (VTI; Siemens Medical Solutions, Mountain View, CA). This study aimed to evaluate the usefulness of VTI in differentiating malignant from benign thyroid nodules.
Methods—This study included 192 consecutive patients with thyroid nodules (n = 219) who underwent surgery for compressive symptoms or suspicion of malignancy. Tissue stiffness on VTI elastography was scored from 1 (soft) to 6 (hard). The VTI scores between malignant and benign thyroid nodules were compared. The intraobserver and interobserver agreement for VTI elastography was also assessed.
Results—On VTI elastography: score 1 was found in 84 nodules (all benign); score 2 in 37 nodules (3 papillary carcinomas and 34 benign nodules); score 3 in 25 nodules (1 medullary carcinoma, 6 papillary carcinomas, and 18 benign nodules); score 4 in 53 nodules (50 papillary carcinomas and 3 benign nodules); score 5 in 17 nodules (14 papillary carcinomas and 3 benign nodules); and score 6 in 3 nodules (all papillary carcinomas). A VTI elasticity score of 4 or greater was highly predictive of malignancy (P< .01), and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 87.0% (67 of 77), 95.8% (136 of 142), 91.8% (67 of 73), 93.1% (136 of 146), and 92.7% (203 of 219), respectively. The κ values were 0.69 for intraobserver agreement and 0.85 for interobserver agreement.
Conclusions—Virtual Touch tissue elasticity imaging has great potential as an adjunctive tool combined with conventional sonography for differential diagnosis between benign and malignant thyroid nodules.
RTE of BENIGN and MALIGNANT CERVICAL LESIONS
Objectives—This study aimed to evaluate the clinical value of ultrasound elastography in the differential diagnosis of benign and malignant cervical lesions and to compare the accuracy of the elasticity score and strain ratio in differentiating cervical lesions.
Methods—B-mode sonography and ultrasound elastography were performed on 84 cervical lesions (40 benign and 44 malignant) in 84 patients. All of the images were obtained transvaginally. The elasticity score was determined by a 5-point scoring method. Calculation of the strain ratio was based on a comparison of the average strain measured in the lesion with the adjacent tissue of the same depth, size, and shape. The
findings were compared with histopathologic results. With the use of receiver operating characteristic curves, the diagnostic value of the elasticity score and strain ratio methods was determined.
Results—The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the elasticity score in the differential diagnosis of cervical lesions were 81.8%, 85.0%, 83.3%, 85.7%, and 81.0%, respectively, whereas those of the strain ratio were 90.9%, 90.0%, 90.5%, 90.9%, and 90.0%. A strain ratio cutoff value of 4.525 was used as a standard to distinguish benign from malignant lesions. The strain ratio values of malignant lesions were much higher than those of benign lesions (range, 4.85–8.91
versus 0.62–4.50). The differences were statistically significant (P < .01).
Conclusions—Ultrasound elastography is a promising technique that is easy and rapid to perform and can help identify cervical lesions that are likely to be malignant. It is obvious that the strain ratio yielded better results than the elasticity score. Both methods are semiquantitative, but quantification of the strain ratio is finer than that of the elasticity score.
Key Words—cervical lesions; elasticity score; gynecologic ultrasound; strain ratio; ultrasound elastography
Thứ Bảy, 22 tháng 3, 2014
Thứ Sáu, 21 tháng 3, 2014
NHÂN CA SARCOMA TÚI MẬT TẠI MEDIC (CA 243)
DISCUSSION
Sarcomas of the gallbladder are rare and represent about 1.5% of all malignant gallbladder
diseases. A variety of tumor types have been described including leiomyosarcoma,
rhabdomyosarcoma, angiomyosarcoma, Kaposi’s sarcoma, malignant fibrous
histiyocytoma, and synovial sarcoma [2]. Leiomyosarcoma of the gallbladder is
an especially rare malignant tumor. By 1984, 105 cases of primary sarcomas of
the gallbladder had been reported, with primary leiomyosarcomas accounting for
7% of them [3].
The diagnoses were established in accordance with the new
World Health Organization classifications for soft tissue tumors and the most
recent soft tissue criteria published. Leiomyosarcoma is defined as a malignant
tumor composed of cells showing distinct smooth muscle features. In the
macroscopy, leiomyosarcoma typically forms a fleshy mass, with colors varying
from grey to white to tan. Large examples often display hemorrhage, necrosis or
a cystic change. The typical histopathologic pattern of leiomyosarcoma is that
of intersecting, sharply marginated groups of spindle cells. In the immunophenotype,
desmin, h-caldesmon, and SMA were positive in a great majority of
leiomyosarcomas. None of these are absolutely specific to smooth muscle and
positivity for two of these markers were more supportive of leiomyosarcoma than
positivity for one alone. Immunostains may be focally positive on CD34,
epithelial membrane antigen (EMA), keratin and S100. A diagnosis should be made
on the appropriate morphologic features, not only on the immunostains. In this
case, immunopositive staining was strong for SMA and vimentin but the typical
histopathologic pattern of leiomyosarcoma had appeared in the hematoxylin and
eosin stain. Therefore other types of the sarcoma were excluded from the
diagnosis.
Leiomyosarcoma is more frequent in women between the ages of
50 and 75 years and usually has a poor prognosis.
The presence of gallstones are invariable and the symptoms presented are those
of chronic cholecystitis [4]. Histopathologically, the majority of these tumors
are high grade and display an epithelioid morphology; but cases with features
of well-differentiated leiomyosarcoma have been described.
According to the National Comprehensive Cancer Network
clinical practice guideline in oncology ver. I. 2011, patients with a
resectable intraabdominal sarcoma should undergo immediate surgical treatment
with a grossly negative margin and and possible interoperative radiation
therapy. The postoperative margin status was the most important factor
contributing to long-term disease free survival [5]. Postoperative treatment
options were dependent on the surgical outcomes and clinical, or pathological
finding following surgery. Postoperative radiation therapy should be considered
in patients with pathological findings of high grade disease following a negative
margin resection (R0 resection) or for microscopic positive margins (R1
resection). For patients with unresectable or disseminated recurrences,
preoperative RT and/or chemotherapy should be considered after a biopsy.
Combination regimens with activity in soft tissue sarcoma include AD
(doxorubicin, dacarbazine), AIM (doxorubicin, ifosfamide, mesna), MAID, and so
on [6,7].
The single agents include dacarbazine, doxorubicin, epirubicin,
gemcitabine, ifosfamide, liposomal doxorubicin and temozolomide [8,9].
The prognosis of sarcoma and leiomyosarcomas of the gallbladder
is dismal, the five year survival rate being less than 5%. This is due to the
fact that at the time of the diagnosis or surgery. Almost 75% of cases involve
the liver [10].
Our patient was also diagnosed at an advanced stage, but he
had no distant organ metastasis. Because R0 resection is expected in this case,
an aggressive surgical approach was attempted. However, soon after, multiple
liver metastasis and peritoneal seeding metastasis were detected in post-operative
evaluations. Therefore additional aggressive multimodality treatments such as
surgery with chemotherapy are the only way to increase the survival rate.
In conclusion, the five year survival rate of leiomyosarcoas
of the gallbladder is less than 5%. However for young and healthy patients with
leiomyosarcomas of the gallbladder, aggressive surgical treatment followed by
adjuvant chemotherapy should increase the survival rate despite high mortality
and morbidity. Because of limited experience with this disease, there is no consensus about management.
Further studies are needed to confirm the benefit of aggressive treatment for
patients with leiomyosarcoma of the gallbladder. Also surgeons will have to tread
very carefully in selection of candidates for surgical treatments.
Primary Leiomyosarcoma of Gallbladder, thesurgery.or.kr 407
Thứ Ba, 18 tháng 3, 2014
PARASITIC THYROID NODULE
Figure 1: Neck ultrasonography. The arrows show two
submandibular nodes with thyroid tissue.
Abstract
Introduction
The presence of benign thyroid tissue that is located on the
side of the neck is extremely rare and not related to the development of the thyroid,
and it is difficult to differentiate it from thyroid carcinoma metastasis.
The parasitic thyroid nodule occurs when thyroid tissue
located in the lateral neck has no relationship
or association with the lymph nodes, and may be defined as a thyroid nodule entirely separate from
the thyroid or attached to it by a narrow pedicle, presenting the same
histology and in the same facial plane as the thyroid, and
should not be associated with lymph nodes.
Case presentation
A 40-year-old Brazilian man without significant past medical
history presented with a large volume multinodular thyroid goiter that caused
deformity and symptoms suggestive of cervical spine compression. He underwent a
total thyroidectomy. His thyroid
function was normal. Ultrasonography showed a heterogeneous thyroid nodule
measuring 3.7cm to the right from midline and 3.3cm to the left from midline
that was associated with two nodules in the left submandibular area measuring
1.43cm and 1.52cm.
Fine needle aspiration confirmed the benign nature of the
gland and thyroid tissue etiology of the two submandibular nodules, located in
level II of the neck. Since the ectopic thyroid tissue in his lateral neck was
suggestive of metastasis of occult primary thyroid carcinoma,the patient underwent a total thyroidectomy plus a left
modified radical neck dissection with preservation of level I. The diagnosis of
multinodular goiter associated with two parasitic thyroid nodules was confirmed
by immunohistochemistry.
Conclusions
We conclude that the parasitic thyroid nodule should be
included in the differential diagnosis of lateral neck masses. The diagnosis
and differentiation of these nodules from metastatic adenopathies of
differentiated thyroid carcinoma has important therapeutic and prognostic implications,
and can lead to avoidance of unnecessary surgeries.
Introduction
Ectopic thyroid tissue is a failure of migration of the
thyroid during the embryonic period [1].It can be present anywhere, from the foramen cecum, which is
at the base of the tongue, tothe normal position of the thyroid, which is between the
second and fourth tracheal rings [1].
Lesions are usually midline, and this position is the most
frequent presentation of ectopicthyroid tissue, presenting in 90% of cases [2]. The terms,
accessory thyroid gland or tissue,have been used in these instances.
The presence of benign thyroid tissue located on the side of
the neck is extremely rare andnot related to the development of the thyroid, and it is
difficult to differentiate from thyroidcarcinoma metastasis [3].
The parasitic thyroid nodule occurs when thyroid tissue
located in the lateral neck has norelationship or association with the lymph nodes, and may be
defined as a thyroid noduleentirely separate from the thyroid or attached to it by a
narrow pedicle, presenting the samehistology and in the same facial plane as the thyroid, and
should not be associated with lymph nodes [1]. We report the case of a parasitic thyroid nodule
in a patient with multinodulargoiter that simulated metastasis of an occult primary
thyroid carcinoma.
Case presentation
A 40-year-old Brazilian man without significant past medical
history presented to our institution in 2011 with a large volume multinodular
thyroid goiter that caused deformity and symptoms suggestive of cervical spine
compression. He underwent a total thyroidectomy. His
thyroid function was normal. Ultrasonography showed a
heterogeneous thyroid nodule measuring 3.7cm to the right from midline and
3.3cm to the left from midline that was associated with two nodules in the left
submandibular area measuring 1.43cm and 1.52cm (Figure 1).
Fine needle aspiration confirmed the benign nature of the
gland and the thyroid tissue etiology of two submandibular nodules located in
level II in his neck. The thyroglobulin levels were not measured in fine needle
aspiration. A frozen section of two submandibular masses was performed before
thyroidectomy. As a result, ectopic thyroid tissue was noted, but the
pathologist did not exclude the possibility of metastasis of occult primary
thyroid carcinoma. Our patient underwent a total thyroidectomy, plus a left
modified radical neck dissection with preservation of level I. The diagnosis of
multinodular goiter associated with two parasitic thyroid nodules was confirmed
by immunohistochemistry.
Microscopically, the goiter was composed of thyroid tissue
with normo- and macroscopic follicles that contained colloid and a coated
monolayer of cells with regular, uniform nuclei that were round to oval and had
fine chromatin, as well as homogeneous eosinophiliccytoplasm. There were no papillary formations, psammoma
bodies or nuclear atypia, such as clear core, slit or pseudo nuclear inclusions
(Figure 2). The material did not have characteristics consistent with
malignancy. Expression of thyroid transcription factor (TTF-1)and thyroglobulin on immunohistochemistry confirmed the thyroid
origin of the goiter (Figure 3). The findings corresponded to a parasitic
thyroid nodule.
Figure 2 Microscopy of goiter showing no signs of goiter
malignancy.
Figure 3 Immunohistochemistry of nodules. a) Expression of
TTF-1; b) expression of thyroglobulin.
Discussion
Thyroid tissue can be located in the lateral region of the
neck under three circumstances.
First, thyroid tissue can be present when there is
mechanical deployment of the tissue after thyroid surgery or cervical trauma;
second, when parasitic thyroid nodules are present without associated lymph
nodes; and third, when there are metastases of thyroid tissue inlymph nodes [1].
The nodules are the result of a parasitic growth of
extracapsular nodular thyroid waste that becomes separated from a preexisting
nodular goiter. It has been proposed that mechanical action of the cervical
muscles over a nodular goiter could cause the separation of these thyroid
residues [4]. Portions of goiter that protrude through the fascia can be cut by
muscle pressure on the thyroid. This explains why the thyroid gland and
parasitic nodules have the same histology and parasitic thyroid nodules have no
evidence of malignancy [5,6].
Conclusion
We conclude that the parasitic thyroid nodule should be included
in the differential diagnosis of lateral neck masses. The confirmation of a
parasitic thyroid nodule requires that it is in the same fascial plane of the
thyroid, has similar histology as the
thyroid, and cannot be associated with lymph nodes. This benign
condition is considered to be rare, and it can cause a serious dilemma if there
is suspicion of an occult primary thyroid carcinoma. The diagnosis and
differentiation of these nodules from metastatic adenopathies of differentiated
thyroid carcinoma have important therapeutic and prognostic implications, and
may prevent unnecessary medical examinations or treatments in the future.
Thứ Hai, 10 tháng 3, 2014
Why does Breast US Find Cancers Mammography doesn't?
Why does breast US find cancers mammography doesn't?
By Kate Madden Yee, AuntMinnie.com staff writerFebruary 20, 2014 -- Most breast cancers detected at screening ultrasound are not seen on mammograms, even in retrospect, which suggests that supplemental screening with ultrasound is beneficial for high-risk women -- especially those with dense tissue, according to a new study published in the February issue of Radiology.No published studies have uncovered why mammography misses cancers that ultrasound finds, according to lead author Dr. Min Sun Bae and colleagues. So Bae's team reviewed the mammograms of women with breast cancers detected at screening ultrasound to determine why they had not been found at mammography.
"The majority of breast cancers detected at screening US are obscured by overlapping dense breast tissue at mammography," the authors wrote. "However, some cancers may have subtle or evident mammographic findings that were overlooked or misinterpreted, and other cancers may reside in an anatomic area that is difficult to detect with mammography" (Radiology, February 2014, Vol. 270:2, pp. 369-377).
The study included 335 ultrasound-detected cancers found between 2003 and 2011 in 329 women with dense breast tissue (BI-RADS density type 2 or higher). Five blinded radiologists reviewed the mammograms to determine whether the findings on negative mammograms should be recalled; three unblinded radiologists re-reviewed the mammograms to determine the reasons the cancers had been missed. The cancers recalled by the blinded radiologists were compared with the reasons they weren't detected, as determined by the unblinded radiologists.
Of the 335 cancers found by screening ultrasound, 63 (19%) were recalled by three or more of the five blinded radiologists, and 272 (81%) showed no mammographic findings that required immediate action. Of these 272 cancers, 131 (48%) were rated as normal by all five blinded radiologists, 82 (30%) were rated as normal by four of the five blinded radiologists, and 59 (22%) were rated as normal by three of the five.
In the unblinded review, 263 (78%) of the cancers were obscured by overlapping dense breast tissue, and nine (3%) were not found at mammography because of difficult anatomic location or poor positioning.
Finally, 63 (19%) of the 335 cancers found at ultrasound and missed at mammography were considered interpretive errors. Of these, 52 (82%) were subtle findings (46 asymmetries and six calcifications) and 11 (18%) were evident (six focal asymmetries, one distortion, and four calcifications).
In women with dense breast tissue, supplemental screening with ultrasound can find cancers that mammography misses, or those that are too subtle for mammography to identify alone, Bae and colleagues concluded.
"Our data support the idea that screening ultrasound can improve cancer detection in women with dense breasts who are at increased or normal risk," they wrote.
Chủ Nhật, 2 tháng 3, 2014
ARFI in DIFFERENTIATION of MALIGNANT from BENIGN THYROID NODULES with a cut-off value of Elastic V=2.545m/s
-----------------------
Acoustic
Radiation Force Impulse (ARFI) Imaging of Thyroid Nodules
Vo Mai Khanh, Nguyen Thien Hung, Phan Thanh Hai
MEDIC MEDICAL CENTER, HCMC, Vietnam
Purpose: The aim of the present study was to evaluate the feasibility of ARFI-measurements in combining of VTI in the thyroid nodule.
Methods and materials: All patients underwent conventional ultrasound, ARFI-imaging and cytological assessment. ARFI-imaging (VTI and VTQ technology) were performed with 9L4 probe, using Siemens (ACUSON S2000) B-mode-ARFI combination transducer.
Results and Discussions: 130 nodules were available for analysis. 103 nodules were benign on cytology, 20 nodules were malignant (papillary carcinomas), and 7 follicular lesions. The average velocity of ARFI-imaging in benign and malignant thyroid nodules was of 2.4 m/s, and of 3.2 m/s, respectively. A sensitivity of 79.4% and specificity of 53.7% of ARFI-imaging could be achieved using a cut-off of 2.19 m/s (area under ROC curve is 0.731, p under 0.0001).
Conclusions: ARFI can be performed in thyroid nodule with reliable results. ARFI might be the reference criteria for differentiation of benign and malignant thyroid nodules.
Purpose: The aim of the present study was to evaluate the feasibility of ARFI-measurements in combining of VTI in the thyroid nodule.
Methods and materials: All patients underwent conventional ultrasound, ARFI-imaging and cytological assessment. ARFI-imaging (VTI and VTQ technology) were performed with 9L4 probe, using Siemens (ACUSON S2000) B-mode-ARFI combination transducer.
Results and Discussions: 130 nodules were available for analysis. 103 nodules were benign on cytology, 20 nodules were malignant (papillary carcinomas), and 7 follicular lesions. The average velocity of ARFI-imaging in benign and malignant thyroid nodules was of 2.4 m/s, and of 3.2 m/s, respectively. A sensitivity of 79.4% and specificity of 53.7% of ARFI-imaging could be achieved using a cut-off of 2.19 m/s (area under ROC curve is 0.731, p under 0.0001).
Conclusions: ARFI can be performed in thyroid nodule with reliable results. ARFI might be the reference criteria for differentiation of benign and malignant thyroid nodules.
PURPOSES:
Acoustic radiation force impulse (ARFI) imaging is a novel
ultrasound-based elastography method enabling quantitative measurement and
qualitative assessment of tissue stiffness. In some recent studies, the
feasibility of ARFI for evaluating the thyroid gland was shown. Most of those
studies used VTQ (Virtual Touch Tissue Quantification) of ARFI-Imaging to
measure the shear wave speed of tissue. However, the VTI (Virtual Touch Tissue
Imaging) was still available, but it was subjective and dependent on the
experience of the sonographer.
The aim of the present study was to evaluate the VTQ of
normal thyroid tissues, benign and malignant thyroid nodules. Besides, VTI
(Virtual Touch Tissue Imaging) of ARFI-Imaging was assessed in these objects as
well.
MATERIALS AND METHODS:
A cross-sectional study was done from August 2011 to October
2012 at Medic Medical Center. One
hundred and thirty nodules underwent
conventional ultrasound, including Color Doppler ultrasound using a 7.5MHz
linear transducer. Next, nodule stiffness were measured and assessed by VTQ and
VTI of ARFI-Imaging (Acuson Siemens S2000).
The Region-of-interest (ROI) placed at the center of nodules and in the
healthy thyroid gland away from thyroid nodules. In addition, five measurements
were performed with the ROI for each nodule.
Exclusion criteria were “X.XX m/s” measurements. With VTI assessment,
each nodule was assessed by 2 separate examiners. Afterward, FNAC (Fine needle
aspiration cytology) under ultrasound guide was used as reference method for
the diagnosis of benign and malignant thyroid nodules.
Statistical analysis was performed using Medcalc for
Windows.
RESULTS:
Patient characteristics:
Age: 45 (range 16 – 69)
Size of nodule: 14mm (range 5 – 47mm)
Table 1: ARFI velocity characteristics:
ARFI velocity (m/s)
|
Normal thyroid
|
Benign nodule
|
Malignant nodule
|
Mean ±
standard deviation
|
1.51 ±
0.07
|
2.15 ±
0.09
|
3.21 ±
0.46
|
Median
|
1.41
|
2.11
|
2.59
|
Minimum
|
0.84
|
0.80
|
0.90
|
Maximum
|
3.00
|
4.04
|
9.22
|
Figure 1:
Receiver-operating characteristic (ROC) curve for VTQ values for diagnosis of
benign and malignant thyroid nodules (AUROC 0.731, p under 0.0001).
Figure 2:
Receiver-operating characteristic (ROC) curve for the difference of VTQ between
normal thyroid tissue and thyroid nodule for diagnosis of benign and malignant
thyroid nodules (AUROC 0.72, p under 0.0001)
Table
2: Frequency table and Chi-square
test for independence of VTI and the differentiation of benign and malignant
nodules:
Codes X
|
VTI
|
Codes Y
|
FNAC
|
Codes X
|
|||||
Codes Y
|
1
|
2
|
3
|
4
|
|
0
|
30
|
10
|
89
|
70
|
199 (76.5%)
|
1
|
51
|
1
|
4
|
5
|
61 (23.5%)
|
81
(31.0%) |
11
(4.2%) |
93
(35.7%) |
75
(29.1%) |
260
|
Chi-square
|
102.553
|
DF
|
3
|
Chi-square statistic
= 102.553, predetermined alpha level of significance = 0.001, degrees of freedom (DF=3), there is a
relationship between VTI and the differentiation of benign and malignant
thyroid nodules.
DISCUSSION:
-
The mean VTQ value of benign thyroid nodules was higher than the
one of normal thyroid tissue and lower than malignant thyroid nodules. It was
reasonable because most of malignant nodules had harder stiffness than benign
nodules.
-
However, the VTQ values were fluctuant and overlapped
among these groups. A malignant nodule
was not completely solid, there were some necrosis regions inside it. Similar
to benign nodule, some calcifications could make it become harder. Besides, the
region of interest (ROI) of Acuson Siemens S2000 was rather big (D=6x5mm) and
unadjustable. With some nodules were smaller than 6mm in size, the ROI could
involve normal thyroid tissue in measuring VTQ. Anyhow, because AUROC was
0.731, VTQ of ARFI-Imaging could be considered as a helpful method in differentiating
of benign and malignant thyroid nodules.
-
Some
thyroid nodules combined with diffuse thyroid diseases (Basedow-Graves’
disease, chronic autoimmune thyroiditis,…) might influent to the result of VTQ.
Recent study by Sporea I. et al, the stiffness of normal thyroid tissue was
lower than in Graves’ disease and chronic autoimmune thyroiditis. In this
study, we got VTQ values of thyroid tissue of the other lobe and measured the
difference of VTQ values between thyroid nodule and thyroid tissue of the other
lobe. The AUROC was 0.72, it meant the difference of VTQ between them would be
considered to be “fairly good” at separating benign and malignant nodules. The
harder nodule and the larger difference of VTQ between nodule and thyroid
tissue of the other lobe were, the larger probability of malignant nodule was.
-
VTI was a qualitative variable therefore it
depended on examiners. We had 2 examiners working separately and blinded with
FNAC results. Each nodule had 2 evaluations in the classification (including 4 groups: dark, iso, bright and mixed color).
The darker VTI was, the more malignant thyroid nodule was. The Chi-square test
result showed a dependance between VTI and the differentiation of benign and
malignant nodules, alpha level of significance = 0.001.
-
But this study existed some disadvantages:
+ This is a prospective study and
FNAC was used as a reference method in differentiating benign and malignant
nodules. As we all know, FNAC was not a gold standard of thyroid nodule’s
diagnosis, histology was. But in our conditions of an out-patient clinic, it
was impossible to have all postoperative results. Multicenters studies are
awaited.
+ Our inclusion criteria was any
size thyroid nodules detected by ultrasound. This might affect the VTQ result
of Acuson Medison S2000 because of the big ROI. We suggested chosing nodules
with > 10mm in size or waiting for another improvement of smaller ROI are.
+ The diffuse thyroid diseases
combined thyroid nodules were popular, but in this study, they were not enough
to do a statistical analysis. Larger studies are awaited.
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