Jürgen Rademaker

Memorial Sloan-Kettering Cancer Center, New York, New York, United States

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Publications (29)106.84 Total impact

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    ABSTRACT: Standard ventilation and perfusion (V˙/Q˙) scintigraphy uses planar images for the diagnosis of pulmonary embolism (PE). To evaluate whether tomographic imaging improves the diagnostic accuracy of the procedure, we compared noncontrast perfusion single-photon emission CT (Q˙-SPECT)/CT scans with planar V˙/Q˙scans in patients at high risk for PE. Between 2006 and 2010, most patients referred for diagnosis of PE underwent both Q˙-SPECT/CT scan and planar V˙/Q˙scintigraphy. All scans were reviewed retrospectively by four observers; planar scans were read with modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II and Prospective Investigative Study of Pulmonary Embolism Diagnosis (PISA-PED) criteria. On Q˙-SPECT/CT scan, any wedge-shaped peripheral perfusion defect occupying > 50% of a segment without corresponding pulmonary parenchymal or pleural disease was considered to show PE. The final diagnosis was established with a composite reference standard that included ECG, ultrasound of lower-extremity veins, D-dimer levels, CT pulmonary angiography (when available), and clinical follow-up for at least 3 months. One hundred six patients with cancer and mean Wells score of 4.4 had sufficient follow-up; 22 patients were given a final diagnosis of PE, and 84 patients were given a final diagnosis of no PE. According to PIOPED II, 13 studies were graded as intermediate probability. Sensitivity and specificity for PE were 50% and 98%, respectively, based on PIOPED II criteria; 86% and 93%, respectively, based on PISA-PED criteria; and 91% and 94%, respectively, based on Q˙-SPECT/CT scan. Seventy-six patients had additional relevant findings on the CT image of the Q˙-SPECT/CT scan. Noncontrast Q˙-SPECT/CT imaging has a higher accuracy than planar V˙/Q˙imaging based on PIOPED II criteria in patients with cancer and a high risk for PE.
    Chest 05/2014; 145(5):1079-88. DOI:10.1378/chest.13-2090 · 7.13 Impact Factor
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    ABSTRACT: Fine needle aspiration cytology (FNAC) is usually used to evaluate palpable nodes in patients with melanoma. The goal of our study is to review the sensitivity and specificity of this technique when applied to palpable but also to nonpalpable nodes. FNAC was performed during 1984-2007 in 1279 patients with suspicious lesions and/or lymph nodes. Indications for biopsy included increased size and/or palpability of nodes or abnormal ultrasound findings such as increased perfusion or focal lesions within the lymph nodes. The sensitivity, specificity, and positive and negative predictive values of FNACs guided by palpation or ultrasound were calculated for all patients and for subgroups of patients with palpable nodes or nonpalpable but sonomorphologically suspicious nodes. A total of 2446 FNACs were performed in 1279 melanoma patients, of which 2011 (82.2%) FNACs had clinically or histologically confirmed results. Increased size and/or palpability of nodes was observed in 376 (29.4%) of 1279 patients, and abnormal ultrasound findings occurred for 903 (70.6%), indicating that a biopsy was needed. FNACs guided by palpation had sensitivity, specificity, and positive and negative predictive values similar to that of FNACs guided by ultrasound (sensitivity = 98.4% vs 97.2%, specificity = 100% vs 99.8%, positive predictive value = 100% vs 99.9%, and negative predictive value = 95.2% vs 96.4%, for palpation-guided FNACs vs ultrasound-guided FNACs, respectively). Results did not differ between patients with the palpable nodes and patients with nonpalpable but sonomorphologically suspicious nodes. Ultrasound-guided FNAC of suspicious lymph nodes and lesions in melanoma patients has a high sensitivity and specificity, and FNAC should not be limited to palpable nodes. FNAC of normal-sized nodes and/or lymph nodes with abnormal ultrasound findings can be used to identify early metastatic disease.
    CancerSpectrum Knowledge Environment 09/2011; 103(23):1771-7. DOI:10.1093/jnci/djr381 · 15.16 Impact Factor
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    ABSTRACT: This study analyzes (1) the value of tyrosinase reverse-transcriptase polymerase chain reaction (RT-PCR) of aspirates obtained by ultrasound-guided fine-needle aspiration cytology (US-FNAC) of sentinel nodes (SNs) in patients with melanoma before sentinel lymph node biopsy (SLNB) and (2) the value of RT-PCR of blood samples of all SLNB patients. Between 2001 and 2003, 127 patients with melanoma (median Breslow depth, 2.1 mm) underwent SLNB. FNAC was performed in all SNs of all patients pre- and post-SLNB. The aspirates were partly shock-frozen for RT-PCR and were partly used for standard cytology. Peripheral blood was collected at the time of SLNB and at every outpatient visit thereafter. Thirty-four (23%) of 120 SNs were positive for melanoma. SN involvement was predicted by US-FNAC with a sensitivity of 82% and a specificity of 72%. Additional tyrosinase RT-PCR revealed the same sensitivity of 82% and a specificity of 72%. At a median follow-up time of 40 months from first blood sample, peripheral-blood RT-PCR was a significant independent predictor of disease-free survival (DFS) and overall survival (OS; P < .001). US-FNAC is highly accurate and eliminates the need for SLNB in 16% of all SLNB patients. RT-PCR of the aspirate or excised SN does not improve sensitivity or specificity. RT-PCR of blood samples predicts DFS and OS.
    Journal of Clinical Oncology 11/2008; 26(35):5742-7. DOI:10.1200/JCO.2007.13.7653 · 17.88 Impact Factor
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    ABSTRACT: Long-term survivors of Hodgkin's lymphoma treated with radiation therapy have an increased incidence of coronary artery disease. The purpose of this study is to describe the coronary CT angiography findings and calcium scores of asymptomatic patients who had mediastinal irradiation for Hodgkin's lymphoma and to evaluate the impact of coronary CT angiography on patient management. We evaluated nine consecutive patients, age range 35-60 years, who had been treated for Hodgkin's lymphoma by radiation therapy between the ages of 11 and 27 years. The total mediastinal dose ranged from 34 to 45 Gy. All patients were evaluated with 64-MDCT with calcium scoring followed by CT angiography of the coronary arteries. Imaging findings and clinical follow-up were analyzed. Eight of nine patients had coronary artery disease. CT showed long segments of diffuse disease; areas of stenosis from soft plaque; and calcification in the proximal right coronary, left anterior descending, and left circumflex arteries. Calcium scores were significantly higher than in other patients of this age group. Additional tests, including selective coronary angiography, were necessary in patients with diffuse disease with calcifications. CT evaluation led to bypass surgery and angioplasty in two patients. Coronary CT angiography and calcium scores are useful tools for evaluation of irradiation-related coronary artery disease. Complementary tests might be necessary in selected patients. Prospective larger studies are needed to better define the role of coronary CT angiography and calcium scores and to establish an algorithm for evaluation and treatment of these patients.
    American Journal of Roentgenology 08/2008; 191(1):32-7. DOI:10.2214/AJR.07.3112 · 2.74 Impact Factor
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    ABSTRACT: Hodgkin lymphoma is one of the most curable cancers because of its sensitivity to both radiation and several chemotherapy agents. Radical radiotherapy alone provided curative therapy for patients who had Hodgkin lymphoma as early as six decades ago. Yet, the radiation field included normal organs, such as breast tissue, thyroid, and coronary arteries, which were at risk for long-term complications. Dedicated imaging approaches have been developed to evaluate late radiation effects on these structures.
    Radiologic Clinics of North America 04/2008; 46(2):419-30, x. DOI:10.1016/j.rcl.2008.04.005 · 1.83 Impact Factor
  • Jürgen Rademaker
    Radiologic Clinics of North America 03/2008; 46(2):xiii. DOI:10.1016/j.rcl.2008.06.001 · 1.83 Impact Factor
  • American Journal of Roentgenology 06/2007; 188(5):1373-9. DOI:10.2214/AJR.06.0759 · 2.74 Impact Factor
  • Jürgen Rademaker
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    ABSTRACT: The diagnosis and management of lymphoma have undergone significant changes in the past 20 years. For example, new immunophenotypic and molecular methods have replaced traditional histology-based classification schemes for lymphoma. Fluorine-18-deoxyglucose (FDG) positron emission tomography (PET) has evolved into a potent staging tool and prognostic indicator in many kinds of lymphoma. The role of radiation therapy, especially in patients who have early-stage Hodgkin's disease, has changed substantially. The introduction of anti-CD 20 antibody therapy (Rituximab) has improved the treatment of B-cell lymphoma. These changes are linked with higher expectations for imaging, such as detection of more subtle lymphoma manifestations, evaluation of residual changes, and better assessment of early response. This article reviews clinical and radiologic features of both Hodgkin's disease and non-Hodgkin's lymphoma. It also describes the radiologic staging of lymphoma and the emerging role of FDG-PET for assessing lymphoma.
    Radiologic Clinics of North America 02/2007; 45(1):69-83. DOI:10.1016/j.rcl.2006.10.006 · 1.83 Impact Factor
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    ABSTRACT: Sentinel lymph node biopsy (SLNB) allows early detection of metastases, thereby enabling early treatment in melanoma patients likely to benefit from adjuvant therapies. This prospective study analyzes the possible benefits of additional ultrasound (US) and fine needle aspiration cytology (FNAC) of sentinel nodes (SN) prior to SLNB. Over a 2-year period 127 melanoma patients with 151 SN were scheduled for SLNB. All SN were initially identified with lymphoscintigraphy, then identified and evaluated by US and the cells aspirated for cytology (FNAC). US findings and FNAC results were compared to surgical findings. Of 127 patients, 114 had one SN each, 12 had two, and one had three. In vivo US achieved a sensitivity of 79% (95% CI: 62-91%) and a specificity of 72% (95% CI: 62-81%). FNAC showed a sensitivity of 59% (95% CI: 41-76%) and a specificity of 100% (95% CI: 95-100%). The combination of these two in vivo methods achieved an overall sensitivity of 82% (95% CI: 65-93%) and an overall specificity of 72% [95% CI: 62-81%]. Combined US and FNAC provides important information prior to SLNB in that both procedures identify metastases in the lymph nodes (sensitivity > 80%). Patients with positive FNAC may proceed directly to complete lymph node dissection (cLND) instead of having initial SLNB. Thus, combined US and FNAC may prevent unnecessary anesthesia and surgical management as well reduce costs. In our study 16% (19/121) fewer SLNB procedures were carried out, subsequently replaced by cLND. For patients with a negative combination of in vivo US and FNAC, SLNB remains the best diagnostic option.
    Annals of Surgical Oncology 12/2006; 13(12):1682-9. DOI:10.1245/s10434-006-9046-4 · 3.94 Impact Factor
  • Jürgen Rademaker
    PET Clinics 07/2006; 1(3):219-230. DOI:10.1016/j.cpet.2006.04.006
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    ABSTRACT: Cowden disease, also known as multiple hamartoma syndromes, is an autosomal dominant disease characterized by numerous benign mucocutaneous tumors, hamartomas of multiple organs, and malignancies of the breast and thyroid. In this report, we present the computed tomographic findings in three patients with Cowden disease. In addition to the classic findings, the patients were diagnosed with spinal neurinoma (n=1), meningioma (n=1), and hepatic hemangioma (n=3). We also review current clinical and genetic concepts that unify Cowden disease.
    Abdominal Imaging 03/2005; 30(2):204-7. DOI:10.1007/s00261-004-0250-z · 1.73 Impact Factor
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    ABSTRACT: To assess the prognostic value of serial reverse transcriptase polymerase chain reaction (RT-PCR) -based measurements of tyrosinase mRNA in peripheral blood of stage II and III melanoma patients. During routine follow-up of American Joint Committee on Cancer stage II and III melanoma patients, serial testing for tyrosinase transcripts in peripheral blood was performed by RT-PCR. The PCR results were compared with the clinical data collected during the follow-up. Over a period of 3 years, 111 patients (78 stage II and 33 stage III patients) were enrolled, and tyrosinase determinations were carried out. The 6-year disease-specific survival probability was 97% for patients always showing negative RT-PCR results and 67% for patients who tested positive at least once. In a Cox proportional hazards model, the prognostic value of sex, age, site of primary tumor, histologic subtype, stage, Breslow's tumor thickness, Clark level, and the time-dependent variable PCR result was assessed. Patients with a positive RT-PCR test had a distinctly higher risk of dying from melanoma, with a hazard ratio of 12.6 (95% CI, 3.4 to 46.3; P < .001). Our study shows a strong association between PCR and disease-specific survival time. Detection of tyrosinase mRNA in peripheral blood may be of similar importance for the clinical course of melanoma as the detection of micrometastatic disease in the sentinel lymph node. Whether a combination of these two factors leads to a better definition of the prognosis of melanoma patients is under investigation in current studies.
    Journal of Clinical Oncology 02/2005; 23(6):1218-27. DOI:10.1200/JCO.2005.04.098 · 17.88 Impact Factor
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    ABSTRACT: To evaluate the safety and the long-term clinical and hemodynamic results of primary stent placement of atherosclerotic calcified stenosis of the infrarenal aorta. Between July 1996 and July 1999, 15 patients (nine male, si- female; mean age, 53.9 years) with symptomatic, calcified aortic stenosis were treated with primary stent placement. Patients underwent abdominal aortography and bilateral lower extremity arteriography. Follow-up was performed in all 15 patients. Technical success was defined as residual stenosis of less than 30% or a resting trans-systolic pressure gradient of less than 10 mm Hg after stent placement. Clinical patency was defined as the absence or improvement of symptoms after stent placement. Hemodynamic patency was defined as a normal triphasic Doppler waveform in the common femoral artery, an ankle-brachial index greater than 0.90, or the absence of a thigh-brachial pressure gradient at rest in either limb. Technical success was achieved in 13 of 15 patients. The two patients considered to be technical failures had resting trans-systolic pressure gradients of 12 and 13 mm Hg, respectively, after stent placement. After the mean follow-up of 36 months, primary clinical and hemodynamic patency rates were 85% and the secondary hemodynamic patency rate was 100%. Two of five symptomatic recurrences during the 36-month follow-up period (range, 12-46 months) were a result of aortic restenosis and were treated with repeated percutaneous transluminal angioplasty. None of the patients required aortic surgery. Complications of the primary procedure included one puncture site infection, one pseudoaneurysm, and one distal embolization, which delayed discharge of three patients. There was no morbidity during the secondary interventions. Primary stent placement as treatment of calcified infrarenal aortic stenosis proved to be safe and also provided durable long-term clinical improvement.
    Journal of Vascular and Interventional Radiology 05/2004; 15(4):353-9. DOI:10.1097/01.RVI.0000121411.46920.27 · 2.15 Impact Factor
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    ABSTRACT: To evaluate clinical and hemodynamical long-term results after laser angioplasty of long occlusions of the superficial femoral artery (SFA). In a prospective trial of 452 patients with long occlusions of the SFA, excimer percutaneous transluminal laser angioplasty (PTLA) for recanalization was applied. The average occlusion length of the SFA was 25.5 cm (range 16-38 cm). The recanalization attempt was done with the crossover technique in 398 patients, in 36 patients with the antegrade technique and in another 18 patients with the transpopliteal technique. The application of laser angioplasty demonstrated a successful recanalization of the SFA in 386/452 patients (85.5%). Recanalization with PTLA was not possible in 66 patients (14.5%). The main reason for the unsuccessful PTLAs was obstructing calcified material (n = 28) resistant to PTLA application. After a follow-up period of 48 months there was a primary, primary-assisted, and secondary patency rate of 22.3%, 40.9%, and 43.2%, respectively. Laser angioplasty of long occlusions of the SFA is a feasible procedure with a low failure rate. Long-term results are promising, but additional interventions are required in most patients if a patency rate of 43.2% is to be achieved after 4 years.
    Acta Radiologica 03/2004; 45(1):23-9. DOI:10.1080/02841850410000746 · 1.35 Impact Factor
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    ABSTRACT: Assessment of the value of ultrasound examination in the determination of extracapsular neoplastic infiltration and soft tissue infiltration of cervical lymph nodes. In a prospective study the results of ultrasound studies in 110 patients with squamous cell carcinoma in the head-neck region were compared with the findings of the histologic examination after neck dissection. Ultrasound examination showed a specificity of 81.8 % in the determination of extracapsular neoplastic infiltration. The sensitivity was only 78.6 % - this was mainly caused by microscopic extracapsular growth, which gave false-negative results. Infiltration of blood vessels were identified in all patients. There was only one false negative diagnosis of muscle infiltration. The specificity (81.8 %) and sensitivity (78.6 %) of ultrasound examinations in the diagnosis of extracapsular infiltration in patients with lymph nodes metastasis is promising. But the examiner has to keep in mind that especially microscopic extracapsular neoplastic infiltration cannot be seen in ultrasound.
    Ultraschall in der Medizin 11/2003; 24(5):323-30. DOI:10.1055/s-2003-42914 · 4.65 Impact Factor
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    ABSTRACT: The purpose of this article is to demonstrate the diagnostic impact of ultrasound in differentiating focal breast lesions with special regard on power Doppler and US contrast agents. The sonographic evaluation of breast lesions has become a standard procedure during the past 15 years. Especially the improvement of B-mode resolution and the use of high-frequency probes increased the diagnostic value of US. Assuming that the neoangiogenetic vascular architecture of solid breast lesions can be depicted reliably by color Doppler, many authors tried to differentiate between benignity and malignancy using Doppler criteria such as flow and morphologic aspects. Additionally, adjuvant techniques, such as harmonic imaging and new US contrast agents, are meant to be success-promising tools. Whereas the sensitivity and specificity of color Doppler have varied in different studies, prognostic prediction and treatment monitoring seem to be the future areas of application. To evaluate sufficiently flow signals of very small vessels with low flow velocity, the use of contrast-enhancing agents may be necessary. Nevertheless, an indispensable condition for successful Doppler-based assessment of the entity of breast lesions is the standardization of techniques, evaluation, analysis and weighting of the parameters.
    European Radiology 02/2003; 13(1):68-79. DOI:10.1007/s00330-002-1413-3 · 4.34 Impact Factor
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    ABSTRACT: To compare the immediate results, complication rates, and long-term outcomes of percutaneous transluminal laser angioplasty (PTLA) versus balloon dilation alone in the treatment of popliteal artery occlusions. In a prospective nonrandomized study conducted between December 1994 and June 2000, 215 symptomatic patients with unilateral popliteal occlusions were treated with either dilation alone (88 patients: 52 men; mean age 62 years, range 48-83) or PTLA (127 patients: 70 men; mean age 64 years, range 49-86) using a 308-nm excimer laser followed by dilation. The average occlusion length was 10.4 cm (range 3-14). PTLA was successful in recanalizing 105 (82.7%) arteries, while the recanalization rate for dilation alone was only 70.4% (62/88; p=0.045). After a mean follow-up of 36 months (range 6-52), the primary and secondary patency rates were 21.7% and 50.8%, respectively, in patients with PTLA and 16.3% and 35.2% in the angioplasty group (p=0.762). The complication rates associated with both techniques were similar. Although initial recanalization may be better with PTLA, it does not appear to add any long-term benefit over balloon dilation alone.
    Journal of Endovascular Therapy 01/2003; 9(6):882-8. DOI:10.1583/1545-1550(2002)009<0882:PTLAVB>2.0.CO;2 · 3.59 Impact Factor
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    ABSTRACT: To compare the ability of standard power Doppler and color harmonic imaging for visualising breast tumor vascularity using ultrasound probes of various frequencies, and to evaluate the influence on diagnostic accuracy using ultrasound contrast agent. Twenty patients (x = 43.6 +/- 11.7 years) with suspected malignancy of the breast underwent power Doppler to evaluate vascularity and to offer a differential diagnosis of the lesion. Two criteria were used for differential diagnosis: The quantitative extent of vascularity ("percentage vessel area", PVA) and the qualitative assessment of vascular architecture. The following power Doppler modes were compared in every patient: Plain and enhanced (Levovist(R)) 9 MHz and 12 MHz standard power mode and enhanced 9 MHz color harmonic imaging-(CHI). The PVA increased from a mean of 2.2 +/- 2.9 % (9 MHz standard plain) via 4.8 +/- 4.1 % (12 MHz standard plain), 9.7 +/- 15.3 % (9 MHz standard enhanced), 17.4 +/- 20.0 % (9 MHz CHI enhanced) up to 19.4 +/- 14.8 % (12 MHz standard enhanced). The perceptibility of the vascular structure was best using the enhanced 12 MHz standard power mode, immediately followed by the enhanced 9 MHz CHI mode. The improved detection of vascular signal did not translate into improved diagnostic accuracy. The highest diagnostic accuracy (95 %) was obtained using the enhanced 9 MHz CHI mode (criterion "PVA") and the enhanced 9 MHz standard power mode (criterion "vascular structure"), whereas the 12 MHz probes delivered insufficient diagnostic accuracy and very low specificity. Best quantitative and qualitative visualisation of the tumor vascularity was achieved using the enhanced 12 MHz standard power mode. Nevertheless, the highest diagnostic accuracy was obtained using enhanced 9 MHz standard power Doppler and enhanced 9 MHz color harmonic imaging. The visualisation of tumor vascularity and, partially, the diagnostic accuracy are improved significantly by color harmonic imaging without changing the probe frequently.
    RöFo - Fortschritte auf dem Gebiet der R 10/2002; 174(9):1132-41. · 1.96 Impact Factor
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    ABSTRACT: To compare the value of B-mode-, plain and contrast enhanced color Doppler ultrasound, CT and MRI with respect to their diagnostic accuracy in palpable enlarged cervical lymph nodes. Thirty patients (18 - 90 years old) with palpable enlarged lymph nodes of the head and neck underwent B-mode-ultrasound, plain and contrast enhanced color Doppler, CT and MRI (gold standard: histologic analysis in 22 and clinical follow up for at least six months in eight patients). The criteria of malignancy were maximal and minimal lymph node diameter, M/Q-ratio, various morphologic criteria (necrosis, hilus line, internal structure, contour, contrast enhancement), spectral Doppler indices, and vascular architecture in color Doppler. The highest sensitivity (= 1.00, specificity = 0.07 - 0.15) was obtained measuring the lymph node diameter independent on the used imaging modality (ultrasound, CT, MRI), the highest specificity (= 1.00, sensitivity = 0.71) analyzing the vascularity of the lymph node by plain color Doppler. The highest diagnostic (= 0.93) accuracy was delivered by contrast enhanced color Doppler analysis of the vascularity. Sensitivity (= 0.94) and specificity (= 0.92) of this imaging modality were only slightly inferior to the top values. Fisher's exact test revealed significant values in differentiating malignant from benign lymph nodes for B-mode- and MR-analysis of the M/Q-ratio (p < 0001/p < 0.05), B-mode morphology (p < 0.00005), plain and contrast enhanced color Doppler analysis of the vascularity (p < 0.0001/p < 0.000005), MR-morphology (p < 0.0001), and CT-morphology (p < 0.005). CT is inferior to MRI, B-mode-ultrasound and contrast-enhanced color Doppler in the differential diagnosis of selectively analyzed, palpably enlarged cervical lymph nodes using the criteria of our study. The analysis of the MR-morphology revealed a slightly inferior diagnostic accuracy to B-mode morphology and color Doppler analysis of the vascularity.
    RöFo - Fortschritte auf dem Gebiet der R 09/2002; 174(9):1099-106. · 1.96 Impact Factor

Publication Stats

399 Citations
106.84 Total Impact Points

Institutions

  • 2005–2014
    • Memorial Sloan-Kettering Cancer Center
      • Department of Radiology
      New York, New York, United States
  • 2001–2011
    • Charité Universitätsmedizin Berlin
      • Department of Dermatology, Venerology and Allergology
      Berlín, Berlin, Germany
  • 2007
    • Cornell University
      Итак, New York, United States
  • 2003–2004
    • Humboldt-Universität zu Berlin
      • Department of Biology
      Berlín, Berlin, Germany