乳房超音波時的彈性造影可減少不必要的切片率
作者：Fran Lowry
出處：WebMD醫學新聞
December 1, 2009 (芝加哥) — 根據發表於北美放射協會第95屆科學會議暨年會的新研究，乳房超音波時進行彈性造影(Elastography imaging)，對於評估乳房病灶和篩選需要切片的病患相當有幫助。
紐約羅徹斯特大學醫學院的Stamatia Destounis醫師表示，彈性造影是可以運用於掃描病患時的一種技術；不含放射線，進行時只需一、兩分鐘，可以對你觀察的部位提供更多資訊。
這項技術包括使用一根超音波探針壓乳房，以測量其底下組織的硬度或抵抗性。
Destounis醫師向Medscape Radiology解釋，這個假設是，堅硬的區域如癌症，會很密實、很硬。它們沒啥移動性，組織不太會移動，在彈性造影上看起來和可以壓縮的軟組織相當不同。癌症(病灶)會比周圍組織硬。
她和研究同僚對193名病患進行198次彈性造影，這些病患之後進行病灶切片。她們發現，彈性造影在59個案例中正確確認58例癌症病灶，一致性比率達98%。
彈性造影也在69個案例中區分出54個良性、惡性病灶，一致性比率為78%。
Destounis醫師向Medscape Radiology表示，癌症病灶在彈性造影上看來比較大，良性病灶小一些。
她解釋，先2D超音波測量病灶，之後使用彈性造影測量，然後一起呈現影像，2D超音波的放左邊、彈性造影的放右邊。如果是癌症，彈性造影的測量會大些，因為彈性造影測量的是硬組織：不只是超音波上看到的組織，還包括腫塊週邊的硬處，癌症處傾向較硬。
她表示，良性病灶小些。測量處不一定清楚，因為有些腫塊是良性的，如纖維囊組織，在彈性造影圖上會融入其餘乳房組織。
她強調，彈性造影並不會消除所有案例的切片需求。
多數時候，進行切片只是為了安全起見，但是，彈性造影可以提供更多資訊，對於良性案例，它可以讓病患免於接受不必要的切片。
東北俄亥俄大學醫學院、Radiology Consultants公司的Richard G. Barr博士，為Medscape Radiology對此研究發表評論時表示，自從彈性造影在2006年獲得美國食品藥物管理局核准之後，他即用它作為乳房超音波檢查的一個標準部份。
在增加彈性造影之後，我們取消了將近50%的乳房切片，我們相信，它是重要的工具，應作為標準乳房超音波的一部份。
如同Destounis醫師，Barr博士表示，有疑慮病灶的病患仍然需要切片以進行組織診斷。他也預期，彈性造影的持續進步將可讓它在不久的將來成為一個篩檢工具。
兩位醫師都向Medscape Radiology表示，消除不必要的切片對婦女來說是一個好消息。
Barr博士表示，即使婦女的切片最後證實為陰性，她依舊會擔心且仍然會感到焦慮。切片檢查有一個很大的情感組成！如果我們可以一開始就告訴她們不需要切片，將有助於緩和她們的焦慮。
Destounis醫師以及Barr博士皆宣告沒有相關財務關係。
北美放射協會(RSNA)第95屆科學會議暨年會：摘要LL-BR4059。發表於2009年11月29日。
Elastography Imaging During Breast Ultrasound Reduces Unnecessary Biopsy rate
By Fran Lowry
Medscape Medical News
December 1, 2009 (Chicago, Illinois) — Elastography imaging performed during breast ultrasound is extremely helpful in evaluating breast lesions and selecting patients who need a biopsy, according to new research presented here at the Radiological Society of North America 95th Scientific Assembly and Annual Meeting.
"Elastography is a technique that you can use as you are scanning the patient; there is no radiation involved, it takes just a minute or 2 to perform, and it gives you more information about what it is you are looking at," said Stamatia Destounis, MD, from the University of Rochester School of Medicine in New York.
The technique involves pressing on the breast with an ultrasound probe to measure the firmness or resistance of the underlying tissue.
"The hypothesis is that firm areas, like cancers, tend to be very dense, very firm. They are not very mobile, and the tissue does not move much and will look different on elastography than soft areas in the breast that are very compressible," Dr. Destounis explained to Medscape Radiology. "A cancer will be stiffer than the surrounding tissue."
She and her colleagues performed 198 elastographies on 193 patients, who then went on to have their lesions biopsied. They found that elastography correctly determined that a lesion was cancerous in 58 of 59 cases, for a concordance rate of 98%.
Elastography also differentiated benign from malignant lesions in 54 of 69 cases, for a concordance rate of 78%.
Cancerous lesions appear larger on elastography, and benign lesions appear smaller, Dr. Destounis told Medscape Radiology.
"The lesion is measured on 2D ultrasound and then measured with elastography, and the images appear side by side, with 2D on the left and the elastography image on the right," she explained. "If it is a cancer, it will measure bigger on the elastogram because elastography measures stiff tissue — not just the tissue that is seen on ultrasound, but the stiffness around the mass — and cancers tend to be stiff."
Benign lesions appear smaller, she said. "It's not always as clear where your measurement is because some masses that are benign, like fibrocystic tissue, can blend into the rest of the breast tissue on the elastogram."
She stressed that elastography is not going to eliminate the need for biopsy in all cases.
"Most of the time you are going to end up biopsying things just to be on the safe side. But elastography gives you more information. In benign cases, it will save patients from undergoing unnecessary biopsies."
Commenting on this study for Medscape Radiology, Richard G. Barr, MD, PhD, from Northeastern Ohio Universities College of Medicine in Rootstown and Radiology Consultants, Inc. in Youngstown, said he has used elastography as a standard part of a breast ultrasound examination since the technique was approved by the US Food and Drug Administration in 2006.
"We cancel approximately 50% of breast biopsies sent to us by adding elastography to the work-up. We believe that it is an important tool and should be included as part of a standard breast ultrasound."
Like Dr. Destounis, Dr. Barr said that patients with suspicious lesions will still need a biopsy for tissue diagnosis.
He also predicted that continued refinement of elastography will allow for it to be used as a screening tool in the near future.
Eliminating unnecessary biopsies will be a good thing for women, both physicians told Medscape Radiology.
"Even when a woman has a biopsy that turns out to be negative, she still can still worry and continue to have a lot of anxiety as a result. There is a huge emotional component to biopsy," Dr. Barr said. "If we are able to tell a woman up front that we don't need to do a biopsy, it really helps to alleviate their anxiety."
Dr. Destounis and Dr. Barr have disclosed no relevant financial relationships.
Radiological Society of North America (RSNA) 95th Scientific Assembly and Annual Meeting: Abstract LL-BR4059. Presented November?29, 2009.
