When diagnostic imaging (such as 2D/3D mammography or ultrasound) identifies a suspicious abnormality, a tissue biopsy is required to establish a definitive pathological diagnosis. Modern interventional breast radiology utilizes minimally invasive, image-guided biopsy techniques tailored to the lesion's specific physical characteristics and visual appearance.
Three primary procedures utilized in clinical practice are Ultrasound-Guided Fine Needle Aspiration (US-FNA), Core Needle Biopsy (CNB), and Tomosynthesis-Guided Vacuum-Assisted Biopsy (Tomo-Guided VAB).
1. Ultrasound-Guided Fine Needle Aspiration (US-FNA)
US-FNA is the least invasive biopsy technique. It uses real-time ultrasound sound waves to guide a fine-gauge needle directly into a target area to collect fluid or free cells.
Needle Size: Fine gauge (typically 21G to 25G, similar to a standard blood-drawing needle).
Sample Type: Cytology (individual cells and fluid aspirate).
Primary Indications:
Therapeutic aspiration and relief of symptomatic, painful fluid-filled cysts.
Evaluation of complicated cysts or abscesses.
Sampling of suspicious axillary (underarm) lymph nodes for staging purposes.
Advantages: Quick, virtually painless (requires minimal or local anesthesia), leaves no scar, and carries the lowest risk of bruising or bleeding.
Limitations: Does not provide intact tissue architecture. Because it yields only isolated cells, cytology cannot reliably distinguish between non-invasive (e.g., Ductal Carcinoma In Situ / DCIS) and invasive carcinoma. It also cannot provide complete biomarker testing (such as ER, PR, or HER2 receptor status).
2. Core Needle Biopsy (CNB)
Core Needle Biopsy is the gold standard initial diagnostic procedure for solid breast masses visible on ultrasound. It employs a spring-loaded automated biopsy gun to retrieve intact solid tissue cylinders.
Needle Size: Medium gauge (typically 14G, occasionally 12G–16G).
Sample Type: Histology (solid, solid-state core tissue samples containing intact cellular structures and stroma).
Guidance: Most commonly performed under real-time Ultrasound guidance (US-CNB), though stereotactic guidance can also be used.
Primary Indications:
Solid palpable or non-palpable breast masses.
Complex solid-and-cystic lesions.
Suspicious focal areas of altered echogenicity visible on ultrasound.
Advantages: Preserves overall tissue architecture, enabling accurate differentiation between invasive cancer and in situ disease. Provides sufficient tissue for full immunohistochemical profiling (ER, PR, HER2, and Ki-67 status).
Limitations: Requires local anesthesia and a tiny skin nick (2–3 mm). Offers smaller sample volumes per core compared to vacuum-assisted devices, which can occasionally lead to sampling underestimation in non-mass or heterogeneous lesions.
3. Tomosynthesis-Guided Vacuum-Assisted Biopsy (Tomo-Guided VAB)
Tomo-Guided VAB (also known as 3D Mammography-guided VAB or Stereotactic VAB) combines 3D digital breast tomosynthesis with a vacuum-assisted biopsy system. It is specifically designed for lesions that are clearly visualized on 3D mammograms but remain invisible (occult) on ultrasound.
Needle Size: Large gauge vacuum probe (typically 8G to 11G).
Sample Type: High-volume histology (multiple large core tissue samples).
Guidance: Digital Breast Tomosynthesis (3D Mammography) with 3D coordinate localization.
Primary Indications:
Microcalcification clusters (the classic early sign of DCIS).
Subtle architectural distortions or fine spiculed areas visible only on 3D mammograms.
Non-mass asymmetric densities occult on ultrasound.
Advantages:
Sub-millimeter Accuracy: 3D coordinate positioning allows pinpoint accuracy for deep, subtle, or faint calcifications.
Single Insertion, Multiple Samples: The vacuum mechanism pulls tissue into the sampling chamber, cuts it, and vacuum-transports it out continuously through a single needle entry point.
Diagnostic Cleansing: Capable of removing entire small calcification clusters or small benign lesions (e.g., papillomas) in one sitting, eliminating the need for open diagnostic surgery.
Clip Placement: A radiopaque tissue marker (clip) is routinely placed through the same probe at the end of the procedure to mark the site for future monitoring or surgical targeting.
Limitations: Requires breast compression during the procedure, carries a higher financial cost, and results in slightly more post-procedure bruising compared to CNB due to the larger probe size.
Comparison Summary Matrix
Clinical Selection Criteria
If a fluid-filled cyst or lymph node is suspected: US-FNA is chosen for rapid aspiration or cytology.
If a solid mass is seen on ultrasound: US-CNB is the first-line procedure due to its high diagnostic accuracy, speed, and patient comfort.
If calcifications or subtle distortions are seen on 3D mammograms only: Tomo-Guided VAB is the modality of choice, providing precise localization and adequate tissue capture to prevent unnecessary open surgical biopsies.
乳房活檢技術比較：超聲波引導細針穿刺、粗針活檢與三維乳房造影引導真空輔助切片檢查
當診斷性影像檢查（如 2D/3D 乳房 X 光造影或超聲波）發現可疑異常時，需要進行組織活檢（切片檢查）以確立最終的病理診斷。現代介入性乳腺放射學會根據病變的物理特性及影像表現，採用微創的影像引導活檢技術。
臨床上最常用的三種主要程序分別為：超聲波引導下細針穿刺細胞學檢查（US-FNA）、粗針組織活檢（CNB），以及 三維乳房造影引導下真空輔助切片檢查（Tomo-Guided VAB）。
1. 超聲波引導下細針穿刺細胞學檢查 (US-FNA)
US-FNA 是侵入性最低的活檢技術。它利用實時超聲波聲波引導細針直接進入目標區域，抽取液體或游離細胞。
針頭大小：細針（通常為 21G 至 25G，與一般抽血針頭相若）。
樣本類型：細胞學（Cytology）（單個細胞及液體抽取物）。
主要適應症：
治療性抽取液體，以紓緩有症狀、引起疼痛的充盈囊腫（水瘤）。
評估複雜性囊腫或膿腫。
抽取可疑腋下淋巴結樣本，作癌症分期之用。
優勢：過程快速、幾乎無痛（僅需最少或局部麻醉）、不留疤痕，且瘀青或出血風險最低。
局限：無法提供完整的組織結構。由於僅能獲取游離細胞，細胞學檢查無法可靠地區分非侵襲性癌症（如乳腺管原位癌 / DCIS）與侵襲性乳癌，亦無法提供完整的生物標記測試（如 ER、PR 或 HER2 受體狀態）。
2. 粗針組織活檢 (Core Needle Biopsy / CNB)
粗針組織活檢是超聲波可見實質性乳房腫塊的黃金標準首選診斷程序。它使用彈簧驅動的自動活檢槍，擷取完整的實質組織圓柱體。
針頭大小：中等針頭（通常為 14G，偶爾為 12G–16G）。
樣本類型：組織學（Histology）（包含完整細胞結構與間質的實質組織條樣本）。
影像引導：最常於 實時超聲波引導下（US-CNB） 進行，但亦可使用立體定位引導。
主要適應症：
實質性可觸及或不可觸及的乳房腫塊。
複雜的實質與囊腫混合性病變。
超聲波下可見的可疑局限性回聲異常區域。
優勢：保留整體組織結構，能精確區分侵襲性乳癌與原位癌。可提供足夠的組織進行全套免疫組化分析（ER、PR、HER2 及 Ki-67 狀態）。
局限：需要局部麻醉及微小皮膚切口（2–3 毫米）。與真空輔助設備相比，每次獲取的樣本體積較小，對於非腫塊型或非均勻性病變，偶爾可能出現採樣評估不足的情況。
3. 三維乳房造影引導下真空輔助切片檢查 (Tomo-Guided VAB)
Tomo-Guided VAB（亦稱 3D 乳房造影引導下 VAB 或立體定位 VAB）結合了 3D 數位乳房斷層造影與真空輔助活檢系統。它專為在 3D 乳房造影下清晰可見、但在超聲波下隱蔽（無法看見）的病變而設計。
針頭大小：大號真空探頭（通常為 8G 至 11G）。
樣本類型：高體積組織學（High-Volume Histology）（多個大型實質組織樣本）。
影像引導：三維乳房斷層造影（3D Mammography / Tomosynthesis） 搭配 3D 坐標定位。
主要適應症：
微鈣化點群（乳腺管原位癌 DCIS 的經典早期跡象）。
僅在 3D 乳房造影下可見的微細結構扭曲或細小刺狀（Spiculed）區域。
超聲波無法顯示的非腫塊型不對稱密度增高區。
優勢：
次毫米級精確度：3D 坐標定位能為深層、微細或淡小之鈣化點提供極高精準度的定位。
單次穿刺，多重採樣：真空機制將組織抽入採樣室切斷，並通過單一進針點連續吸出，無需反覆進針。
診斷性切除：能夠在一次程序中將整個微細鈣化群或小良性病變（如乳頭狀瘤）切除，免除傳統開刀診斷手術的需要。
放置金屬標記牌：程序結束時，會順帶通過同一探頭放置不透 X 光的組織標記牌（Clip），標記位置以便日後監測或外科定位。
局限：過程中需要壓迫乳房，費用較高，且因探頭較大，術後瘀青程度比粗針活檢稍微明顯。
比較摘要表
| Parameter | Fine Needle Aspiration (US-FNA) | Core Needle Biopsy (CNB) | Tomo-Guided VAB (Tomo-VAB) |
|---|---|---|---|
| Primary Guidance | Real-time Ultrasound | Real-time Ultrasound | 3D Mammography (Tomosynthesis) |
| Needle Gauge | 21G – 25G (Very Fine) | 14G (Medium) | 8G – 11G (Large Vacuum Probe) |
| Specimen Collected | Cytology (Fluid/Cells) | Histology (Solid Cores) | High-Volume Histology |
| Ideal Target Lesion | Cysts, fluid collections, lymph nodes | Solid masses, complex lesions | Microcalcifications, subtle 3D distortions |
| Invasive vs. In Situ | Cannot distinguish | Distinguishes accurately | Distinguishes accurately |
| Biomarker Testing | Limited / Unsuitable | Full ER/PR/HER2 panel | Full ER/PR/HER2 panel |
| Tissue Clip Marker | Rarely required | Optional (depends on lesion size) | Routine & Standard |
| Incision Needed | None (puncture only) | Tiny skin nick (~2–3 mm) | Small skin incision (~3–4 mm) |
| 評估項目 | 細針穿刺細胞學檢查 (US-FNA) | 粗針組織活檢 (CNB) | 三維造影引導真空輔助切片 (Tomo-VAB) |
|---|---|---|---|
| 主要影像引導 | 實時超聲波 | 實時超聲波 | 3D 乳房造影（斷層造影） |
| 針頭粗細 | 21G – 25G（極細針） | 14G（中等針頭） | 8G – 11G（大型真空探頭） |
| 採集樣本 | 細胞學（液體/細胞） | 組織學（實質組織條） | 高體積組織學樣本 |
| 最理想目標病變 | 囊腫（水瘤）、積液、淋巴結 | 實質腫塊、複雜混合性病變 | 微鈣化點、3D 造影微細結構扭曲 |
| 區分侵襲性與原位癌 | 無法區分 | 能精確區分 | 能精確區分 |
| 腫瘤生物標記測試 | 有限 / 不適用 | 完整（ER/PR/HER2 等） | 完整（ER/PR/HER2 等） |
| 放置金屬標記牌 | 極少需要 | 視乎病變大小可選 | 標準常規程序 |
| 切口需求 | 無（僅需穿刺） | 微小皮膚切口（~2–3 毫米） | 小型皮膚切口（~3–4 毫米） |