Clinical Focus

  • Diagnostic Radiology

Academic Appointments

  • Clinical Associate Professor, Radiology

Professional Education

  • Internship: Penn State College of Medicine (1999) PA
  • Medical Education: Stanford University School of Medicine (1998) CA
  • Residency: Stanford University School of Medicine (2003) CA
  • Board Certification: American Board of Radiology, Diagnostic Radiology (2003)

Clinical Trials

  • Radiofrequency-Guided Localization in Patients With Abnormal Breast Tissue Undergoing Lumpectomy Not Recruiting

    This pilot clinical trial studies the use of the radiofrequency-guided localization in patients with abnormal breast tissue undergoing lumpectomy (a type of breast-sparing surgery). The radiofrequency identification localization system consists of an implantable radiofrequency identification tag and a hand-held radiofrequency reader to mark abnormal breast tissue before surgery and later surgically retrieve them. Radiofrequency-guided localization may make it easier to find and remove abnormal breast tissue during lumpectomy.

    Stanford is currently not accepting patients for this trial. For more information, please contact Sumita Sood, 650-723-0186.

    View full details

2023-24 Courses

All Publications

  • Nipple Sparing Mastectomy Technique to Reduce Ischemic Complications: Preserving Important Blood Flow Based on Breast MRI. World journal of surgery Karin, M. R., Pal, S., Ikeda, D., Silverstein, M., Momeni, A. 2022


    Nipple-sparing mastectomy (NSM) with immediate breast reconstruction is commonly performed. However, nipple areolar complex (NAC) and mastectomy skin necrosis represent significant complications requiring reoperation and revision. Breast MRI, often obtained for oncologic assessment, can visualize the dominant breast and NAC vascular supply. This study describes the surgical technique utilizing breast MRI blood flow information to preserve important NAC blood supply, thereby, reducing ischemic complications.After IRB approval, a prospectively maintained database of all NSM by a single breast surgeon from 2018 to 2020 formed the study group. Preoperative contrast enhanced Breast MRI analysis determined the dominant NAC blood supply. Intraoperatively, the dominant Internal Mammary Artery Perforator (IMP) to the NAC was preserved (IMP-NSM). The IMP-NSM surgical technique preserving the IMP blood flow, evaluation of breast MRI blood flow patterns, surgical findings, and ischemic complications were analyzed.114 NSM were performed in 74 patients (mean age: 49 years [range, 22-73 years], BMI 25.8 kg/m2 [range, 19-41 kg/m2]). Breast MRI identified the dominant IMP to the NAC in 92%. IMP preservation was successful in 89% (101/114). Necrosis requiring NAC removal occurred in 0.9% (1/114), and skin necrosis reoperation in 1.8% (2/114). Including all post-operative necrosis occurred in 10.5% (12/114), statistically significantly lower compared to the literature for NSM assessing MRI blood flow data without surgical IMP preservation (necrosis 24.4%, p < 0.001) (Bahl et al. in J Am Coll Surg 223(2):279-285, 2016) utilizing Doppler for IMP preservation (necrosis 37%, p < 0.001) (Swistel et al. in Plast Reconstr Surg Glob Open 2(8):e198, 2014) and dividing the IMP in all (necrosis 31.4%, p < 0.001) (Ahn et al. in Eur J Surg Oncol 44(8):1170-1176, 2018).The IMP-NSM surgical technique preserves the dominant blood supply to the NAC, thereby, decreasing ischemic complications.

    View details for DOI 10.1007/s00268-022-06764-x

    View details for PubMedID 36207418

  • Nipple-sparing mastectomy with internal mammary artery perforator preservation based on breast MRI reduces ischemic complications Karin, M., Pal, S., Silverstein, M., Momeni, A. SPRINGER. 2022: 205-207
  • Prognostic values of quantitative and morphological parameters of dbPET in patients with luminal-type breast cancer: A pilot study Miyake, K., Nakamoto, Y., Ikeda, D., Iagaru, A., Daniel, B., Lipson, J., Pal, S., Mittra, E., Guo, H., Kanao, S., Kataoka, M., Toi, M., Togashi, K. SOC NUCLEAR MEDICINE INC. 2020
  • A randomized phase II study comparing surgical excision versus NeOadjuvant Radiotherapy followed by delayed surgical excision of Ductal carcinoma In Situ (NORDIS) Wapnir, I., DeMartini, W., Allison, K., Stone, K., Dirbas, F., Marquez, C., Ikeda, D., Pal, S., Tsai, J., Yang, R., West, R., McMillan, A., Telli, M., Horst, K. AMER ASSOC CANCER RESEARCH. 2020
  • Pretreatment Tattoo Marking of Suspicious Axillary Lymph Nodes: Reliability and Correlation with Sentinel Lymph Node ANNALS OF SURGICAL ONCOLOGY Patel, R., MacKerricher, W., Tsai, J., Choy, N., Lipson, J., Ikeda, D., Pal, S., De Martini, W., Allison, K. H., Wapnir, I. L. 2019; 26 (8): 2452–58
  • Pretreatment Tattoo Marking of Suspicious Axillary Lymph Nodes: Reliability and Correlation with Sentinel Lymph Node. Annals of surgical oncology Patel, R., MacKerricher, W., Tsai, J., Choy, N., Lipson, J., Ikeda, D., Pal, S., De Martini, W., Allison, K. H., Wapnir, I. L. 2019


    BACKGROUND: Tattooing is an alternative method for marking biopsied axillary lymph nodes (ALNs) before initiation of treatments for newly diagnosed breast cancer. Detection of black ink-stained nodes is performed under direct visualization at surgery and is combined with sentinel node (SLN) mapping procedures.METHODS: Women with newly diagnosed breast cancer who underwent fine or core-needle biopsy of suspicious ALNs were recruited. The nodal cortex and perinodal soft tissue was injected with 0.1-1.0ml of Spot (GI Supply) black ink under ultrasound guidance. Intraoperatively, black stained nodes were removed along with SLNs, noting concordance between the two.RESULTS: Sixty-six evaluable patients were enrolled (2013-2017). Nineteen received surgery first (Group 1) and 47 neoadjuvant therapy (NAT, Group 2). The average number of nodes tattooed was 1.16 for Group 1 and 1.04 for Group 2. The average interval from tattoo to surgery was 21days (range 1-62) for Group 1 and 148days (range 71-257) for Group 2. The tattooed node(s) were visually identified at surgery and corresponded to the sentinel lymph node(s) in 98.5% of cases (18/19 in Group 1 and 47/47 in Group 2). Of the 14 patients in Group 2 whose nodes remained positive following NAT, the tattooed node was the SLN associated with carcinoma.CONCLUSIONS: Tattooing is an alternative method for marking biopsied ALNs. Tattooed nodes coincided with SLNs in 98.5% of cases. This technique is advantageous, because it allows for fewer procedures and lower costs compared with other methods.

    View details for PubMedID 31087176

  • Improving Performance of Mammographic Breast Positioning in an Academic Radiology Practice AMERICAN JOURNAL OF ROENTGENOLOGY Pal, S., Ikeda, D. M., Jesinger, R. A., Mickelsen, L., Chen, C. A., Larson, D. B. 2018; 210 (4): 807–15


    The purpose of this project was to achieve sustained improvement in mammographic breast positioning in our department.Between June 2013 and December 2016, we conducted a team-based performance improvement initiative with the goal of improving mammographic positioning. The team of technologists and radiologists established quantitative measures of positioning performance based on American College of Radiology (ACR) criteria, audited at least 35 mammograms per week for positioning quality, displayed performance in dashboards, provided technologists with positioning training, developed a supportive environment fostering technologist and radiologist communication surrounding mammographic positioning, and employed a mammography positioning coach to develop, improve, and maintain technologist positioning performance. Statistical significance in changes in the percentage of mammograms passing the ACR criteria were evaluated using a two-proportion z test.A baseline mammogram audit performed in June 2013 showed that 67% (82/122) met ACR passing criteria for positioning. Performance improved to 80% (588/739; p < 0.01) after positioning training and technologist and radiologist agreement on positioning criteria. With individual technologist feedback, positioning further improved, with 91% of mammograms passing ACR criteria (p < 0.01). Seven months later, performance temporarily decreased to 80% but improved to 89% with implementation of a positioning coach. The overall mean performance of 91% has been sustained for 23 months. The program cost approximately $30,000 to develop, $42,000 to launch, and $25,000 per year to maintain. Almost all costs were related to personnel time.Dedicated performance improvement methods may achieve significant and sustained improvement in mammographic breast positioning, which may better enable facilities to pass the recently instated Enhancing Quality Using the Inspection Program portion of a practice's annual Mammography Quality Standards Act inspections.

    View details for PubMedID 29412019

  • Association of morphological and quantitative parameters on dedicated breast PET with the expression status of hormone receptors, HER2 and Ki-67 in breast cancers Miyake, K., Ikeda, D., Lagaru, A., Quon, A., Daniel, B., Lipson, J., Pal, S., Mittra, E., Guo, H., Nakamoto, Y., Nishimatsu, K., Kanao, S., Kataoka, M., Togashi, K. SOC NUCLEAR MEDICINE INC. 2017
  • Correlation of percutaneously biopsied axillary lymph nodes marked with black tattoo ink prior to neoadjuvant chemotherapy with sentinel lymph nodes in breast cancer patients Choy, N., Lipson, J., Pal, S., Ikeda, D., Trinh, L., Allison, K., Ozawa, M., Wheeler, A., Wapnir, I. AMER ASSOC CANCER RESEARCH. 2015
  • Rim Sign in Breast Lesions on Diffusion-Weighted Magnetic Resonance Imaging: Diagnostic Accuracy and Clinical Usefulness JOURNAL OF MAGNETIC RESONANCE IMAGING Kang, B. J., Lipson, J. A., Planey, K. R., Zackrisson, S., Ikeda, D. M., Kao, J., Pal, S., Moran, C. J., Daniel, B. L. 2015; 41 (3): 616-623


    To investigate the diagnostic accuracy and clinical usefulness of the rim sign in breast lesions observed in diffusion-weighted magnetic resonance imaging (DWI).The magnetic resonance imaging (MRI) findings of 98 pathologically confirmed lesions (62 malignant and 36 benign) in 84 patients were included. Five breast radiologists were asked to independently review the breast MRI results, to grade the degree of high peripheral signal, the "rim sign," in the DWI, and to confirm the mean apparent diffusion coefficient (ADCmean ) values. We analyzed the diagnostic accuracy and compared the consensus (when ≥4 of 5 independent reviewers agreed) results of the rim sign with the ADCmean values. Additionally, we evaluated the correlation between the dynamic contrast-enhanced (DCE)-MRI morphologic appearance and DWI rim sign.According to the consensus results, the rim sign in DWI was observed on 59.7% of malignant lesions and 19.4% of benign lesions. The sensitivity, specificity, and area under the curve (AUC) value for the rim sign in DWI were 59.7%, 80.6%, and 0.701, respectively. The sensitivity, specificity, and AUC value for the ADCmean value (criteria ≤1.46 × 10(-3) mm(2) /sec) were 82.3%, 63.9%, and 0.731, respectively. Based on consensus, no correlation was observed between the DCE-MRI and DWI rim signs.In DWI, a high-signal rim is a valuable morphological feature for improving specificity in DWI.J. Magn. Reson. Imaging 2014. © 2014 Wiley Periodicals, Inc.

    View details for DOI 10.1002/jmri.24617

    View details for Web of Science ID 000349967700006

    View details for PubMedID 24585455

  • Initial results with preoperative tattooing of biopsied axillary lymph nodes and correlation to sentinel lymph nodes in breast cancer patients. Annals of surgical oncology Choy, N., Lipson, J., Porter, C., Ozawa, M., Kieryn, A., Pal, S., Kao, J., Trinh, L., Wheeler, A., Ikeda, D., Jensen, K., Allison, K., Wapnir, I. 2015; 22 (2): 377-382


    Pretreatment evaluation of axillary lymph nodes (ALNs) and marking of biopsied nodes in patients with newly diagnosed breast cancer is becoming routine practice. We sought to test tattooing of biopsied ALNs with a sterile black carbon suspension (Spot™). The intraoperative success of identifying tattooed ALNs and their concordance to sentinel nodes was determined.Women with suspicious ALNs and newly diagnosed breast cancer underwent palpation and/or ultrasound-guided fine needle aspiration or core needle biopsy, followed by injection of 0.1 to 0.5 ml of Spot™ ink into the cortex of ALNs and adjacent soft tissue. Group I underwent surgery first, and group II underwent neoadjuvant therapy followed by surgery. Identification of black pigment and concordance between sentinel and tattooed nodes was evaluated.Twenty-eight patients were tattooed, 16 in group I and 12 in group II. Seventeen cases had evidence of atypia or metastases, 8 (50 %) in group I and 9 (75 %) in group II. Average number of days from tattooing to surgery was 22.9 (group I) and 130 (group II). Black tattoo ink was visualized intraoperatively in all cases, except one case with microscopic black pigment only. Fourteen group I and 10 group II patients had black pigment on histological examination of ALNs. Sentinel nodes corresponded to tattooed nodes in all except one group I patient with a tattooed non-sentinel node.Tattooed nodes are visible intraoperatively, even months later. This approach obviates the need for additional localization procedures during axillary staging.

    View details for DOI 10.1245/s10434-014-4034-6

    View details for PubMedID 25164040

  • Initial Results With Black Ink Tattooing of Biopsied Axillary Lymph Nodes Choy, N. S., Lipson, J., Kieryn, A., Porter, C., Ikeda, D., Pal, S., Trinh, L., Ozawa, M., Allison, K., Jensen, K., Wapnir, I. SPRINGER. 2014: 35–36
  • Why Are Patients Noncompliant With Follow-Up Recommendations After MRI-Guided Core Needle Biopsy of Suspicious Breast Lesions? AJR. American journal of roentgenology Thompson, M. O., Lipson, J., Daniel, B., Harrigal, C., Mullarkey, P., Pal, S., Thompson, A. C., Ikeda, D. 2013; 201 (6): 1391-1400


    The objective of this study was to investigate patient and breast MRI characteristics associated with noncompliance with recommended follow-up after MRI-guided core needle biopsy of suspicious breast lesions.A retrospective review was performed of 576 breast lesions biopsied under MRI guidance between 2007 and 2010. Patient follow-up was obtained from the medical record and from contact with referring physicians.Of 415 women who underwent 576 MRI-guided core needle biopsies for suspicious breast lesions, 123 (29.6%) patients representing 154 of 576 (26.7%) lesions were noncompliant with recommended excision or 6-month MRI follow-up. Referring physicians provided information for 63% (97/154) of lesions in noncompliant patients, of which 49.5% (48/97) were followed by mammography instead of excision or MRI. Noncompliance with MRI follow-up was significantly associated with referral for biopsy by outside hospital physicians (odds ratio [OR], 2.40; p = 0.0001) and with referral for screening MRI (1.46; p = 0.093) and biopsy of a focus or foci lesion (1.63; p = 0.088). Among 178 lesions in patients compliant with follow-up MRI after MRI-guided core needle biopsy, 7.9% (14/178) had abnormal follow-up MRI results, half of which (3.9%, 7/178) were found on repeat biopsy to be high-risk or malignant.Institutions performing MRI-guided core biopsies should be aware that patients referred from outside institutions are more likely to be noncompliant with recommended follow-up. Strategies to improve follow-up should include educating patients on the difference between mammography and MRI follow-up.

    View details for DOI 10.2214/AJR.12.10282

    View details for PubMedID 24261382

  • Freehand MRI-Guided Preoperative Needle Localization of Breast Lesions After MRI-Guided Vacuum-Assisted Core Needle Biopsy Without Marker Placement JOURNAL OF MAGNETIC RESONANCE IMAGING van de Ven, S. M., Lin, M. C., Daniel, B. L., Sareen, P., Lipson, J. A., Pal, S., Dirbas, F. M., Ikeda, D. M. 2010; 32 (1): 101-109


    To evaluate the feasibility of magnetic resonance imaging (MRI)-guided preoperative needle localization (PNL) of breast lesions previously sampled by MRI-guided vacuum-assisted core needle biopsy (VACNB) without marker placement.We reviewed 15 women with 16 breast lesions undergoing MRI-guided VACNB without marker placement who subsequently underwent MRI-guided PNL, both on an open 0.5T magnet using freehand techniques. Mammograms and specimen radiographs were rated for lesion visibility; MRI images were rated for lesion visibility and hematoma formation. Imaging findings were correlated with pathology.The average prebiopsy lesion size was 16 mm (range 4-50 mm) with 13/16 lesions located in mammographically dense breasts. Eight hematomas formed during VACNB (average size 13 mm, range 8-19 mm). PNL was performed for VACNB pathologies of cancer (5), high-risk lesions (5), or benign but discordant findings (6) at 2-78 days following VACNB. PNL targeted the lesion (2), hematoma (4), or surrounding breast architecture (10). Wire placement was successful in all 16 lesions. Final pathology showed six cancers, five high-risk lesions, and five benign findings.MRI-guided PNL is successful in removing lesions that have previously undergone VACNB without marker placement by targeting the residual lesion, hematoma, or surrounding breast architecture, even in mammographically dense breasts.

    View details for DOI 10.1002/jmri.22148

    View details for Web of Science ID 000279439600013

    View details for PubMedID 20575077

  • Estrogen receptor-negative invasive breast cancer: Imaging features of tumors with and without human epidermal growth factor receptor type 2 overexpression RADIOLOGY Wang, Y., Ikeda, D. M., Narasimhan, B., Longacre, T. A., Bleicher, R. J., Pal, S., Jackman, R. J., Jeffrey, S. S. 2008; 246 (2): 367-375


    To prospectively determine if estrogen receptor (ER)-negative human epidermal growth factor receptor type 2 (HER2)-positive and ER-negative HER2-negative breast cancers have distinguishing clinical and imaging features with use of retrospectively identified patients and tissue samples.This HIPAA-compliant study was institutional review board approved. Informed consent was obtained from living patients and waived for deceased patients. Mean patient age at diagnosis was 53 years (range, 31-84 years). Clinical history; histopathologic, mammographic, and breast sonographic findings; and HER2 status as determined with immunohistochemistry or fluorescent in situ hybridization were evaluated in 56 women with ER-negative breast cancer. Imaging appearances and clinicopathologic characteristics were correlated with tumor HER2 status. P < .05 indicated a significant difference.Lesion margins on mammograms (P = .028) and sonograms (P = .023), calcifications on mammograms (P = .003), and clinical cancer stage at diagnosis (P = .029) were significantly associated with HER2 status. In contrast to ER-negative HER2-negative tumors, ER-negative HER2-positive tumors were more likely to have spiculated margins (56% vs 15%), be associated with calcifications (65% vs 21%), and be detected at a higher cancer stage (74% vs 57%).Biologic diversity of cancers may manifest in imaging characteristics, and, conversely, studying the range of imaging features of cancers may help refine current molecular phenotypes.

    View details for DOI 10.1148/radio1.2462070169

    View details for Web of Science ID 000252796300005

    View details for PubMedID 18180338

  • Mammographic screening in women at increased risk of breast cancer after treatment of Hodgkin's disease American-Society-of-Breast-Disease Symposium Kwong, A., Hancock, S. L., Bloom, J. R., Pal, S., Birdwell, R. L., Mariscal, C., Ikeda, D. M. BLACKWELL PUBLISHING. 2008: 39–48


    Treatment regimens for Hodgkin's disease (HD) that have included radiation to lymph node regions in the thorax have contributed to high rates of long-term disease-free survival. However, incidental radiation exposure of breast tissue in young women has significantly increased the risk of breast cancer compared to expected rates in the general population. After informing patients about risks associated with previous treatment of HD, we studied screening mammograms and call-back rates in women at increased risk for developing breast cancer at a younger age. We contacted by mail a cohort of 291 women between 25 and 55 years of age who had received thoracic irradiation before 35 years of age for HD with or without chemotherapy. Subjects were offered information about risks identified after HD therapy with questionnaires to assess response to this information. Ten patients refused participation, 93 did not respond, and 21 were excluded after they reported a prior diagnosis of invasive (1) or in situ (2) breast cancer. One hundred and sixty seven women received information about secondary breast cancer risk and were advised to initiate or maintain mammographic screening. Available mammograms were reviewed by two radiologists and classified according to the ACR BI-RADS Mammography Lexicon. Abnormal findings were correlated to pathology results from biopsies. One hundred and fifteen subjects reported that they obtained new mammograms during the period of the study. Ninety-nine were available for secondary review. Patients were studied an average of 16.9 years after HD treatment (Range: 4.5-32.5 years) at an average of 41 years of age (range 25-55 years). High density breast tissue was identified in 60% (60/99). Seventeen of the women (17.2%) were recalled for further imaging. This was more common in women with heterogeneously dense breast tissue. Seven of those recalled (41%) were advised to undergo biopsies that identified ductal carcinoma in situ (DCIS) in one and benign findings in the others. Among 16 women whose mammograms were unavailable for review, three were diagnosed with DCIS; two of these had microscopic evidence of invasive breast cancer. The four in situ or microinvasive cancers were diagnosed in the study participants at 25-40 years of age and from 5 to 23 years after HD therapy. Biopsies were performed because mammograms detected microcalcifications without palpable abnormality in three of these cases. Women who have had thoracic nodal irradiation for Hodgkin's disease have an increased risk of developing secondary breast cancer at an unusually young age. As expected in younger women, high density breast tissue was common on mammography, and the recall and biopsy rates were unusually high. However, early mammographic screening facilitated diagnosis of in situ and early invasive cancer in 3.5% of our subjects.

    View details for Web of Science ID 000252124800006

    View details for PubMedID 18186864

  • MRI-guided needle localization of suspicious breast lesions: results of a freehand technique EUROPEAN RADIOLOGY van den Bosch, M. A., Daniel, B. L., Pal, S., Nowels, K. W., Birdwell, R. L., Jeffrey, S. S., Ikeda, D. M. 2006; 16 (8): 1811-1817


    Magnetic resonance imaging (MRI) can detect clinically and mammographically occult breast lesions. In this study we report the results of MRI-guided needle localization of suspicious breast lesions by using a freehand technique. Preoperative MRI-guided single-needle localization was performed in 220 patients with 304 MRI-only breast lesions at our hospital between January 1997 and July 2004. Procedures were performed in an open 0.5-T Signa-SP imager allowing real-time monitoring, with patient in prone position, by using a dedicated breast coil. MRI-compatible hookwires were placed in a noncompressed breast by using a freehand technique. MRI findings were correlated with pathology and follow-up. MRI-guided needle localization was performed for a single lesion in 150 patients, for two lesions in 56 patients, and for three lesions in 14 patients. Histopathologic analysis of these 304 lesions showed 104 (34%) malignant lesions, 51 (17%) high-risk lesions, and 149 (49%) benign lesions. The overall lesion size ranged from 2.0-65.0 mm (mean 11.2 mm). No direct complications occurred. Follow-up MRI in 54 patients showed that two (3.7%) lesions were missed by surgical biopsy. MRI-guided freehand needle localization is accurate and allows localization of lesions anterior in the breast, the axillary region, and near the chest wall.

    View details for DOI 10.1007/s00330-006-0214-5

    View details for Web of Science ID 000238860700022

    View details for PubMedID 16683117

  • Compliance with recommended follow-up after fine-needle aspiration biopsy of nonpalpable breast lesions: A retrospective study 1995 Annual Meeting of the Radiological-Society-of-North-America Pal, S., Ikeda, D. M., Birdwell, R. L. RADIOLOGICAL SOC NORTH AMER. 1996: 71–74


    To determine compliance with recommendations for mammographic or surgical follow-up after fine-needle aspiration biopsy of non-palpable breast lesions.The authors reviewed the medical records of 419 patients in whom surgical or mammographic follow-up had been recommended after fine-needle aspiration biopsy. Mammographic, clinical, and follow-up findings were correlated with patient outcome. Of 466 lesions, 395 lesions in 359 patients (age range, 24-89 years; average age, 55 years) were nonpalpable and composed the study.Excisional biopsy was recommended in 141 cases (35.7%) and close-interval mammographic surveillance in 165 (41.8%). Biopsy was performed in 122 (86.5%) of the 141 cases in which it was recommended. Of 165 cases in which follow-up mammography was recommended, 84 (50.9%) were resolved at the close of the study. In the remaining cases, women either did not return (n = 24), were followed up elsewhere or moved (n = 35), were lost to follow-up by their physicians (n = 17), or were lost to follow-up for other reasons (n = 5).Noncompliance with follow-up recommendations is an important issue undermining the benefits of fine-needle aspiration biopsy. Difficulty in tracking patients hinders assessment of patient compliance.

    View details for Web of Science ID A1996VJ11400019

    View details for PubMedID 8816523