Introduction: Axillary lymph node status is the most important factor determining prognosis in br... more Introduction: Axillary lymph node status is the most important factor determining prognosis in breast cancer patients. Assessment of nodal status currently requires surgical resection. First a sentinel lymph node biopsy (SLNB) is performed, which, if positive for metastasis, is followed by a complete axillary lymph node dissection. These procedures are associated with morbidity and, in retrospect, are often performed unnecessarily. The development of a noninvasive procedure that can spare patients unnecessary surgery would be an important improvement. We have initiated a trial comparing non-invasive gadofosveset enhanced 3T imaging-based staging , to surgical axillary staging. The hypothesis is that gadofosveset, a blood–pool agent with a high albumin binding, will be transported with albumin-rich lymph and like USPIOs accumulate in a higher concentration in healthy than in metastatic lymph nodes. As a result the transverse relaxation rate in healthy nodes would increase which would cause a negative contrast effect on diffusion-weighted (DWI) scans, selectively preserving the signal of metastatic lymph nodes. The performance of the in vivo 3T MRI is controlled by 7T ex vivo MRI of all surgical specimens, which is followed by a node-to-node matching of all imaged nodes with pathology [1]. This abstract describes the results of the retrospective 3T MRI characterization of axillary lymph nodes of breast cancer patients, with pathology as the gold standard. Material and Methods: We included 16 consecutive patients about to undergo SLNB during the work-up of a histologically proven breast cancer with a diameter of at least 2cm, as determined on mammography and ultrasound. Four days prior to the operation the patients were scanned on a 3T MR (Philips Health Care, Cleveland, USA), in prone position with the arms above the head in order to achieve the most comparable position to the position during operation. Four phased array, receive only, coils were used (Philips Healthcare, Best, the Netherlands), positioned around both breasts and both armpits. The scan protocol consisted of a 3D T1 weighted turbo field echo (TFE) [TR/TE 5.1/2.3ms, flip angle 10o, FOV 201.6x400x300mm, resolution 0.9mm isotropic] before and after contrast; a 3D T2*-map, obtained from a multi-echo gradient echo sequence [TR/first TE/ΔTE 21/4.6/4.6ms, 4 echoes, flip angle 15o, FOV 99.9x400x300mm, slice thickness 0.9mm, in plane resolution 1mm] post contrast and a multi-slice STIR based DWI [TR/TI/TE 18223/240/47ms, FOV 201.6x400x300mm, slice thickness 3.6mm, in plane resolution 3.0mm, b-values 0, 100 and 500s/mm] before and after contrast. Gadofosveset (0,03 mmol/kg i.v.) was manually injected followed by a 10cc saline flush. On the ipsilateral side of the breast cancer an MRI marker grid was taped to the axilla. The grid was also drawn on the patient. This drawing was still visible during surgery. For all excised nodes, the anatomical level and the position of the node with respect to the drawn grid was noted. For each patient the location of all nodes was detailed on a hand-drawn map of the axilla. To aid in the node-to-node matching of in-vivo imaging and subsequent pathologic examination, the excised nodes were scanned at 7T prior to further processing[1]. Retrospectively the mean absolute T2* relaxation times and the post contrast signal intensity of the lesion to spinal cord ratio (LSR) were determined for all excised lymph nodes. The LSR was determined on high-pass thresholded axial b=500s/mm scans using loose hand-drawn regions of interest. The threshold was set at 1.5 times the noise-level. Statistical evaluation was performed by means of logistic regression analyses according to the generalized estimating equations method, correcting for the fact that several lymph nodes were derived from the same patient. Results: 3 patients were excluded from analysis because of severe motioninduced degradation of the DWI scans. 13 patients were analyzed from whom in total 35 lymph nodes were excised. 9 nodes, from 7 patients, contained metastases. 2 patients (8 nodes, of which one had a metastasis) did not receive a T2* weighted scan due to fatigue of the patient. Table 1 shows the mean post contrast signal intensity ratio (LSR) and the mean T2* relaxation times for all nodes. Metastatic nodes had a significantly longer T2* time and significantly higher LSR compared to non-metastatic nodes. Discussion & Conclusion Inclusion was limited to 16 patients with 35 analyzed nodes, and a prospective, per-patient MRI diagnosis of nodal status was not attempted in this study. As a proof of principle however, the in vivo results suggest metastatic nodes are selectively highlighted on gadofosveset-enhanced diffusion-weighted images, presumably because of a difference in transverse relaxation rate. Metastatic depots are hypothesized to interfere with gadofosveset accumulation, which would explain the shorter T2* of healthy nodes compared to the metastatic nodes,…
Scandinavian Journal of Rheumatology, Mar 28, 2023
U test was used to assess difference in OST total score between RA patients and controls. Receive... more U test was used to assess difference in OST total score between RA patients and controls. Receiver operator characteristics (ROC) analysis was used to assess discriminative capability of OST on joint level (OST versus GSUS, PDUS, GSUS+PDUS, swelling or tenderness during clinical examination). False discovery
Poster: "ESSR 2012 / P-0105 / Feasibility study of high resolution PDw imaging of cartilage ... more Poster: "ESSR 2012 / P-0105 / Feasibility study of high resolution PDw imaging of cartilage of the ankle at 7Tesla MRI " by: " M. A. Korteweg 1, F. Visser2, M. Italiaander2, P. Luijten2, M. Maas1, D. W. J. Klomp2; 1Amsterdam/NL, 2Utrecht/NL"
Poster: "ESSR 2013 / P-0004 / Feasibility study of high resolution imaging of cartilage of t... more Poster: "ESSR 2013 / P-0004 / Feasibility study of high resolution imaging of cartilage of the CMC1 joint at 7Tesla MRI" by: "M. A. Korteweg1, F. Visser2, P. Chernohorsky1, S. D. Strackee1, P. Luijten2, M. Maas1, D. W. J. Klomp2; 1Amsterdam/NL, 2Utrecht/NL"
To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultra... more To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (DUS) could replace digital subtraction angiography (DSA) for diagnosing internal carotid artery (ICA) stenosis in regional centres with less specialized technicians and equipment, such as a 1 Tesla MRI machine. MATERIALS AND METHODS: Sixty-six consecutive, symptomatic patients with ICA stenosis, as evidenced using DSA, were included. In the first 34 patients DUS was validated and cutoff criteria were established. Data were analysed by receiver operating characteristic curve and logistic regression. Two observers analysed the DUS and CE-MRA results of 32 patients. Stenoses were categorized in accordance with North American Symptomatic Endarterectomy Trial (NASCET) measurement criteria. RESULTS: Peak systolic velocity (PSV) in the ICA was defined as a better parameter for defining stenosis than end diastolic velocity and the PSV ICA:common carotid artery ratio. The optimal PSV threshold was 230 cm/s. Four ICAs were not interpretable on DUS, and one on CE-MRA. Two patients did not undergo CE-MRA. The sensitivities and specificities were calculated: for DUS these were 100% and 68% respectively; for observer 1 on CE-MRA these were 93% and 89%, respectively; for observer 2 these were 92% and 87%, respectively. The sensitivity and specificity for combined DUS/CE-MRA were 100% and 85%, respectively. Seventy-eight percent of CE-MRA and DUS correlated. The weighted Kappa for CE-MRA and DSA were 0.8 and 0.9, respectively. CONCLUSION: DUS and CE-MRA are effective non-invasive methods for selecting patients with ICA stenosis for carotid endarterectomy in non-specialized centres using a 1 T machine. The present results suggest that no referrals to more specialized centres for non-invasive diagnostic work-up for carotid artery stenoses will be necessary.
Background This pilot study explored the value of a dedicated extremity magnetic resonance imagin... more Background This pilot study explored the value of a dedicated extremity magnetic resonance imaging (MRI) scanner by focusing on the qualitative depiction of important wrist structures in common wrist pathologies, the overall image quality, artifacts, and participant experience in undergoing the examinations. Methods Images of the right wrist of 10 healthy adult volunteers were acquired with a 0.31-Tesla (T) dedicated extremity MRI and a 3-T MRI system, using a dedicated wrist coil. Images were separately evaluated by three radiologists. Paired images were randomized and graded for the visibility of anatomical details, including the triangular fibrocartilage complex (TFCC; central disc, meniscus homolog, and ulnar attachment), carpal ligaments (scapholunate [SL] and lunotriquetral [LT] ligaments), intercarpal cartilage, and median and ulnar nerves. Mean values and standard deviations of evaluation results were calculated for each sequence. Participants' experience in undergoing the examination in both MRI scanners was explored using a questionnaire. Results The mean values of anatomic structures and overall image quality were significantly in favor of the 3-T MRI scanner, compared with the dedicated extremity MRI scanner. With respect to patient satisfaction in undergoing the examination, the overall trend suggested that patients were more in favor of the dedicated extremity MRI scanner. Conclusion For defining the real clinical value of the dedicated MRI scanner in the treatment of hand and wrist pathology, studies focused on pathologies are needed, which is certainly warranted, considering the important benefits of these devices including lower costs and higher accessibility for both patients and health care providers.
CardioVascular and Interventional Radiology, Dec 18, 2008
Atherosclerosis of femoropopliteal arteries is an important cause of morbidity and mortality. Per... more Atherosclerosis of femoropopliteal arteries is an important cause of morbidity and mortality. Percutaneous transluminal angioplasty (PTA) has only limited success in treating these arteries, mainly because of the high rate of recurrent stenosis. Cryoplasty has been proposed as a technique which might improve treatment outcome. This study reports our single-center experience with cryoplasty. Thirty-two claudicants, 33 arteries, in whom conservative therapy failed, were consecutively included. Duplex ultrasound (US), angiography, and ankle-brachial index (ABI) measurement were performed before the procedure; ABI and duplex US, 2 weeks and 3, 6, and 12 months after the procedure. Patients' symptoms were categorized according to the Rutherford classification. Lesions were classified as TASC A, B, or C according to angiographic appearance. Differences in ABI before and after the procedure were defined as significant at p < 0.05 by paired t-test. Patency was evaluated using duplex US by determining the peak systolic velocity ratio. Sixteen TASC A lesions, 13 TASC B lesions, and 4 TASC C lesions were included. ABI improved significantly for TASC A lesions 2 weeks and 3 months postprocedure. Patency after 2 weeks, 6 months, and 12 months was 93%, 67%, and 64% for TASC A lesions, 83%, 31%, and 31% for TASC B lesions, and 100%, 50%, and 33% for TASC C lesions, respectively. In conclusion, cryoplasty has good immediate success rates and patency rates similar to the results of conventional PTA in the literature.
Background This pilot study explored the value of a dedicated extremity magnetic resonance imagin... more Background This pilot study explored the value of a dedicated extremity magnetic resonance imaging (MRI) scanner by focusing on the qualitative depiction of important wrist structures in common wrist pathologies, the overall image quality, artifacts, and participant experience in undergoing the examinations. Methods Images of the right wrist of 10 healthy adult volunteers were acquired with a 0.31-Tesla (T) dedicated extremity MRI and a 3-T MRI system, using a dedicated wrist coil. Images were separately evaluated by three radiologists. Paired images were randomized and graded for the visibility of anatomical details, including the triangular fibrocartilage complex (TFCC; central disc, meniscus homolog, and ulnar attachment), carpal ligaments (scapholunate [SL] and lunotriquetral [LT] ligaments), intercarpal cartilage, and median and ulnar nerves. Mean values and standard deviations of evaluation results were calculated for each sequence. Participants' experience in undergoing t...
Poster: "ESSR 2013 / P-0004 / Feasibility study of high resolution imaging of cartilage of t... more Poster: "ESSR 2013 / P-0004 / Feasibility study of high resolution imaging of cartilage of the CMC1 joint at 7Tesla MRI" by: "M. A. Korteweg1, F. Visser2, P. Chernohorsky1, S. D. Strackee1, P. Luijten2, M. Maas1, D. W. J. Klomp2; 1Amsterdam/NL, 2Utrecht/NL"
Poster: "ESSR 2012 / P-0105 / Feasibility study of high resolution PDw imaging of cartilage ... more Poster: "ESSR 2012 / P-0105 / Feasibility study of high resolution PDw imaging of cartilage of the ankle at 7Tesla MRI " by: " M. A. Korteweg 1, F. Visser2, M. Italiaander2, P. Luijten2, M. Maas1, D. W. J. Klomp2; 1Amsterdam/NL, 2Utrecht/NL"
technique which is widely available and less time consuming. Patients who are positive on AUS gui... more technique which is widely available and less time consuming. Patients who are positive on AUS guided FNAC can proceed for ALND directly thereby obviating the need for SNB.
Ultra-high field 7Tesla (7T) MRI offers important advantages for oncological practice. Due to the... more Ultra-high field 7Tesla (7T) MRI offers important advantages for oncological practice. Due to the high field strength, new opportunities have arisen for the imaging of cancer. The newly acquired ultra-high resolution facilitates the possibility of detailed anatomical imaging. Also molecular processes can now be visualized in greater detail. This allows structured imaging of the metabolism of a malignant process. The first in vivo results from patients with prostate-and breast cancer demonstrated that 7T imaging with high spatial and spectral resolution is indeed feasible. Additionally at high field strengths other scanning techniques can be applied than at lower field strengths. Such techniques can accurately detect calcifications in breast cancer, for example. 7T MRI has the potential of performing quantitative molecular imaging and personalized assessment of cancer patients and will play a part in the early diagnosis, tumor characterization and therapy monitoring of malignant lesions.
In diagnosing osteochondral defects, MRI and CT have similar diagnostic accuracies. CT is faster,... more In diagnosing osteochondral defects, MRI and CT have similar diagnostic accuracies. CT is faster, better for preoperative planning, cheaper and allows the ankle to be depicted in various anatomical positions in a 3D manner. CT enables clear delineation of the true osteochondral defect, will not overcall the size due to bone marrow edema (as seen on MRI), and helps assessing the extent of the osseous defect in the presence of cystic defects.
Objective To determine the sensitivity and specificity of 3.0-tesla (T) magnetic resonance imagin... more Objective To determine the sensitivity and specificity of 3.0-tesla (T) magnetic resonance imaging (MRI) and a dedicated hand coil in diagnosing scapholunate ligament (SLL) injury compared with intraoperative findings. Methods From January 2006 until September 2010, 3.0-T MRI scans were performed on 38 wrists (37 patients) with clinically unclear but suspected lesions of the SLL. These scans were evaluated by two experienced radiologists. Radiological findings were compared with intraoperative findings during arthrotomy. Sensitivity, specificity, accuracy, and positive and negative predictive value were calculated. Results An SLL lesion was identified during arthrotomy in 37 wrists. The first radiologist identified an SLL lesion on MRI in 26 wrists, all of which were confirmed intraoperatively. The second radiologist identified SLL lesions in 31 patients; however, intraoperatively it was found that there was no lesion of the ligament in one patient. Sensitivity ranged from 70 to 81% with a specificity of 100% and a positive predictive value of 97 to 100%. Accuracy measured 71 to 79%. Conclusions 3.0-T MRI of the wrist is moderately sensitive and very specific for detection of SLL lesions. However, if there is a high clinical suspicion of an SLL rupture, a 3.0-T MRI does not often have an additional value. Level of Evidence Diagnostic, level II
Here we describe our first experience with contrast-enhanced (CE) MRI of breast cancer at 7 tesla... more Here we describe our first experience with contrast-enhanced (CE) MRI of breast cancer at 7 tesla (T), compared to 3T and histopathology. A 52 year old female patient with a mammographically suspicious breast mass (BI-RADS V) underwent 7 T CE-MRI. Results were described according to the BI-RADS-MRI criteria and compared to 3T and histopathology. After contrast administration, a homogeneously enhancing, irregular spiculated mass was depicted at both 3T and 7 T; sizes were identical. The most malignant kinetic curve was characterized by a rapid initial rise followed by a wash-out pattern in the delayed phase, i.e. a type 3 curve, at both field strengths. Even though T1-effects of contrast agents are suggested to be reduced at higher fields, quantification of contrast enhancement-to-noise ratio showed a ratio of 4.6 at 7 T and 2.8 at 3T when comparing contrast-to-noise of the mass before and after contrast administration. Both examinations, using a single dose of gadolinium-based contrast agent, achieved good image quality. Final histopathological evaluation showed an invasive ductulolobular carcinoma with an intraductal component. This initial experience suggests that clinical contrast-enhanced 7 T MRI of the breast is technically feasible and may allow BI-RADS-conform analysis.
Journal of magnetic resonance imaging : JMRI, 2012
To determine lipid composition of excised healthy and metastatic sentinel lymph nodes of breast c... more To determine lipid composition of excised healthy and metastatic sentinel lymph nodes of breast cancer patients, as lipids are a potential discriminatory marker for malignancy.
Objective To characterize ex vivo healthy human axillary lymph nodes on 7 Tesla MRI and to correl... more Objective To characterize ex vivo healthy human axillary lymph nodes on 7 Tesla MRI and to correlate the findings with pathological analysis as a first step towards non-invasive staging of breast cancer patients in the future. Methods Four axillary lymph node dissection (ALND) specimens from 2 autopsy patients, who had no cancer, were examined on a clinical 7 Tesla MRI system. For morphological analysis a 3D T1-weighted fat-suppressed fast-field-echo [isotropic resolution 180 μm] was acquired. For quantitative analyses 2D T1-, 3D T2-, T2*-and diffusion-weighted images were acquired. The ALNDs were mapped and stained for precise correlation of MRI to pathology. Nodes were sliced in 3 μm sections, Haematoxylin & Eosin stained, and examined by an experienced pathologist. Results MRI detected all 45 nodes and 6 additional nodes that were not detected at pathological analysis. B-cell follicles, efferent-and afferent lymph vessels and blood vessels were identified. Mean T1, T2, T2*, ADC values (± standard deviation) were 944±113 ms, 32±2 ms, 16± 2 ms, 0.39±0.09•10 −3 mm 2 /s, respectively. Conclusions 7 Tesla MRI of ex vivo human axillary lymph nodes correlated well with pathology. MRI detected all nodes present in the specimens and allowed visualization of fine structural detail. Pathology-correlated quantitative MRI data are presented.
To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultra... more To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (DUS) could replace digital subtraction angiography (DSA) for diagnosing internal carotid artery (ICA) stenosis in regional centres with less specialized technicians and equipment, such as a 1 Tesla MRI machine. MATERIALS AND METHODS: Sixty-six consecutive, symptomatic patients with ICA stenosis, as evidenced using DSA, were included. In the first 34 patients DUS was validated and cutoff criteria were established. Data were analysed by receiver operating characteristic curve and logistic regression. Two observers analysed the DUS and CE-MRA results of 32 patients. Stenoses were categorized in accordance with North American Symptomatic Endarterectomy Trial (NASCET) measurement criteria. RESULTS: Peak systolic velocity (PSV) in the ICA was defined as a better parameter for defining stenosis than end diastolic velocity and the PSV ICA:common carotid artery ratio. The optimal PSV threshold was 230 cm/s. Four ICAs were not interpretable on DUS, and one on CE-MRA. Two patients did not undergo CE-MRA. The sensitivities and specificities were calculated: for DUS these were 100% and 68% respectively; for observer 1 on CE-MRA these were 93% and 89%, respectively; for observer 2 these were 92% and 87%, respectively. The sensitivity and specificity for combined DUS/CE-MRA were 100% and 85%, respectively. Seventy-eight percent of CE-MRA and DUS correlated. The weighted Kappa for CE-MRA and DSA were 0.8 and 0.9, respectively. CONCLUSION: DUS and CE-MRA are effective non-invasive methods for selecting patients with ICA stenosis for carotid endarterectomy in non-specialized centres using a 1 T machine. The present results suggest that no referrals to more specialized centres for non-invasive diagnostic work-up for carotid artery stenoses will be necessary.
Introduction: Axillary lymph node status is the most important factor determining prognosis in br... more Introduction: Axillary lymph node status is the most important factor determining prognosis in breast cancer patients. Assessment of nodal status currently requires surgical resection. First a sentinel lymph node biopsy (SLNB) is performed, which, if positive for metastasis, is followed by a complete axillary lymph node dissection. These procedures are associated with morbidity and, in retrospect, are often performed unnecessarily. The development of a noninvasive procedure that can spare patients unnecessary surgery would be an important improvement. We have initiated a trial comparing non-invasive gadofosveset enhanced 3T imaging-based staging , to surgical axillary staging. The hypothesis is that gadofosveset, a blood–pool agent with a high albumin binding, will be transported with albumin-rich lymph and like USPIOs accumulate in a higher concentration in healthy than in metastatic lymph nodes. As a result the transverse relaxation rate in healthy nodes would increase which would cause a negative contrast effect on diffusion-weighted (DWI) scans, selectively preserving the signal of metastatic lymph nodes. The performance of the in vivo 3T MRI is controlled by 7T ex vivo MRI of all surgical specimens, which is followed by a node-to-node matching of all imaged nodes with pathology [1]. This abstract describes the results of the retrospective 3T MRI characterization of axillary lymph nodes of breast cancer patients, with pathology as the gold standard. Material and Methods: We included 16 consecutive patients about to undergo SLNB during the work-up of a histologically proven breast cancer with a diameter of at least 2cm, as determined on mammography and ultrasound. Four days prior to the operation the patients were scanned on a 3T MR (Philips Health Care, Cleveland, USA), in prone position with the arms above the head in order to achieve the most comparable position to the position during operation. Four phased array, receive only, coils were used (Philips Healthcare, Best, the Netherlands), positioned around both breasts and both armpits. The scan protocol consisted of a 3D T1 weighted turbo field echo (TFE) [TR/TE 5.1/2.3ms, flip angle 10o, FOV 201.6x400x300mm, resolution 0.9mm isotropic] before and after contrast; a 3D T2*-map, obtained from a multi-echo gradient echo sequence [TR/first TE/ΔTE 21/4.6/4.6ms, 4 echoes, flip angle 15o, FOV 99.9x400x300mm, slice thickness 0.9mm, in plane resolution 1mm] post contrast and a multi-slice STIR based DWI [TR/TI/TE 18223/240/47ms, FOV 201.6x400x300mm, slice thickness 3.6mm, in plane resolution 3.0mm, b-values 0, 100 and 500s/mm] before and after contrast. Gadofosveset (0,03 mmol/kg i.v.) was manually injected followed by a 10cc saline flush. On the ipsilateral side of the breast cancer an MRI marker grid was taped to the axilla. The grid was also drawn on the patient. This drawing was still visible during surgery. For all excised nodes, the anatomical level and the position of the node with respect to the drawn grid was noted. For each patient the location of all nodes was detailed on a hand-drawn map of the axilla. To aid in the node-to-node matching of in-vivo imaging and subsequent pathologic examination, the excised nodes were scanned at 7T prior to further processing[1]. Retrospectively the mean absolute T2* relaxation times and the post contrast signal intensity of the lesion to spinal cord ratio (LSR) were determined for all excised lymph nodes. The LSR was determined on high-pass thresholded axial b=500s/mm scans using loose hand-drawn regions of interest. The threshold was set at 1.5 times the noise-level. Statistical evaluation was performed by means of logistic regression analyses according to the generalized estimating equations method, correcting for the fact that several lymph nodes were derived from the same patient. Results: 3 patients were excluded from analysis because of severe motioninduced degradation of the DWI scans. 13 patients were analyzed from whom in total 35 lymph nodes were excised. 9 nodes, from 7 patients, contained metastases. 2 patients (8 nodes, of which one had a metastasis) did not receive a T2* weighted scan due to fatigue of the patient. Table 1 shows the mean post contrast signal intensity ratio (LSR) and the mean T2* relaxation times for all nodes. Metastatic nodes had a significantly longer T2* time and significantly higher LSR compared to non-metastatic nodes. Discussion & Conclusion Inclusion was limited to 16 patients with 35 analyzed nodes, and a prospective, per-patient MRI diagnosis of nodal status was not attempted in this study. As a proof of principle however, the in vivo results suggest metastatic nodes are selectively highlighted on gadofosveset-enhanced diffusion-weighted images, presumably because of a difference in transverse relaxation rate. Metastatic depots are hypothesized to interfere with gadofosveset accumulation, which would explain the shorter T2* of healthy nodes compared to the metastatic nodes,…
Scandinavian Journal of Rheumatology, Mar 28, 2023
U test was used to assess difference in OST total score between RA patients and controls. Receive... more U test was used to assess difference in OST total score between RA patients and controls. Receiver operator characteristics (ROC) analysis was used to assess discriminative capability of OST on joint level (OST versus GSUS, PDUS, GSUS+PDUS, swelling or tenderness during clinical examination). False discovery
Poster: "ESSR 2012 / P-0105 / Feasibility study of high resolution PDw imaging of cartilage ... more Poster: "ESSR 2012 / P-0105 / Feasibility study of high resolution PDw imaging of cartilage of the ankle at 7Tesla MRI " by: " M. A. Korteweg 1, F. Visser2, M. Italiaander2, P. Luijten2, M. Maas1, D. W. J. Klomp2; 1Amsterdam/NL, 2Utrecht/NL"
Poster: "ESSR 2013 / P-0004 / Feasibility study of high resolution imaging of cartilage of t... more Poster: "ESSR 2013 / P-0004 / Feasibility study of high resolution imaging of cartilage of the CMC1 joint at 7Tesla MRI" by: "M. A. Korteweg1, F. Visser2, P. Chernohorsky1, S. D. Strackee1, P. Luijten2, M. Maas1, D. W. J. Klomp2; 1Amsterdam/NL, 2Utrecht/NL"
To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultra... more To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (DUS) could replace digital subtraction angiography (DSA) for diagnosing internal carotid artery (ICA) stenosis in regional centres with less specialized technicians and equipment, such as a 1 Tesla MRI machine. MATERIALS AND METHODS: Sixty-six consecutive, symptomatic patients with ICA stenosis, as evidenced using DSA, were included. In the first 34 patients DUS was validated and cutoff criteria were established. Data were analysed by receiver operating characteristic curve and logistic regression. Two observers analysed the DUS and CE-MRA results of 32 patients. Stenoses were categorized in accordance with North American Symptomatic Endarterectomy Trial (NASCET) measurement criteria. RESULTS: Peak systolic velocity (PSV) in the ICA was defined as a better parameter for defining stenosis than end diastolic velocity and the PSV ICA:common carotid artery ratio. The optimal PSV threshold was 230 cm/s. Four ICAs were not interpretable on DUS, and one on CE-MRA. Two patients did not undergo CE-MRA. The sensitivities and specificities were calculated: for DUS these were 100% and 68% respectively; for observer 1 on CE-MRA these were 93% and 89%, respectively; for observer 2 these were 92% and 87%, respectively. The sensitivity and specificity for combined DUS/CE-MRA were 100% and 85%, respectively. Seventy-eight percent of CE-MRA and DUS correlated. The weighted Kappa for CE-MRA and DSA were 0.8 and 0.9, respectively. CONCLUSION: DUS and CE-MRA are effective non-invasive methods for selecting patients with ICA stenosis for carotid endarterectomy in non-specialized centres using a 1 T machine. The present results suggest that no referrals to more specialized centres for non-invasive diagnostic work-up for carotid artery stenoses will be necessary.
Background This pilot study explored the value of a dedicated extremity magnetic resonance imagin... more Background This pilot study explored the value of a dedicated extremity magnetic resonance imaging (MRI) scanner by focusing on the qualitative depiction of important wrist structures in common wrist pathologies, the overall image quality, artifacts, and participant experience in undergoing the examinations. Methods Images of the right wrist of 10 healthy adult volunteers were acquired with a 0.31-Tesla (T) dedicated extremity MRI and a 3-T MRI system, using a dedicated wrist coil. Images were separately evaluated by three radiologists. Paired images were randomized and graded for the visibility of anatomical details, including the triangular fibrocartilage complex (TFCC; central disc, meniscus homolog, and ulnar attachment), carpal ligaments (scapholunate [SL] and lunotriquetral [LT] ligaments), intercarpal cartilage, and median and ulnar nerves. Mean values and standard deviations of evaluation results were calculated for each sequence. Participants' experience in undergoing the examination in both MRI scanners was explored using a questionnaire. Results The mean values of anatomic structures and overall image quality were significantly in favor of the 3-T MRI scanner, compared with the dedicated extremity MRI scanner. With respect to patient satisfaction in undergoing the examination, the overall trend suggested that patients were more in favor of the dedicated extremity MRI scanner. Conclusion For defining the real clinical value of the dedicated MRI scanner in the treatment of hand and wrist pathology, studies focused on pathologies are needed, which is certainly warranted, considering the important benefits of these devices including lower costs and higher accessibility for both patients and health care providers.
CardioVascular and Interventional Radiology, Dec 18, 2008
Atherosclerosis of femoropopliteal arteries is an important cause of morbidity and mortality. Per... more Atherosclerosis of femoropopliteal arteries is an important cause of morbidity and mortality. Percutaneous transluminal angioplasty (PTA) has only limited success in treating these arteries, mainly because of the high rate of recurrent stenosis. Cryoplasty has been proposed as a technique which might improve treatment outcome. This study reports our single-center experience with cryoplasty. Thirty-two claudicants, 33 arteries, in whom conservative therapy failed, were consecutively included. Duplex ultrasound (US), angiography, and ankle-brachial index (ABI) measurement were performed before the procedure; ABI and duplex US, 2 weeks and 3, 6, and 12 months after the procedure. Patients' symptoms were categorized according to the Rutherford classification. Lesions were classified as TASC A, B, or C according to angiographic appearance. Differences in ABI before and after the procedure were defined as significant at p < 0.05 by paired t-test. Patency was evaluated using duplex US by determining the peak systolic velocity ratio. Sixteen TASC A lesions, 13 TASC B lesions, and 4 TASC C lesions were included. ABI improved significantly for TASC A lesions 2 weeks and 3 months postprocedure. Patency after 2 weeks, 6 months, and 12 months was 93%, 67%, and 64% for TASC A lesions, 83%, 31%, and 31% for TASC B lesions, and 100%, 50%, and 33% for TASC C lesions, respectively. In conclusion, cryoplasty has good immediate success rates and patency rates similar to the results of conventional PTA in the literature.
Background This pilot study explored the value of a dedicated extremity magnetic resonance imagin... more Background This pilot study explored the value of a dedicated extremity magnetic resonance imaging (MRI) scanner by focusing on the qualitative depiction of important wrist structures in common wrist pathologies, the overall image quality, artifacts, and participant experience in undergoing the examinations. Methods Images of the right wrist of 10 healthy adult volunteers were acquired with a 0.31-Tesla (T) dedicated extremity MRI and a 3-T MRI system, using a dedicated wrist coil. Images were separately evaluated by three radiologists. Paired images were randomized and graded for the visibility of anatomical details, including the triangular fibrocartilage complex (TFCC; central disc, meniscus homolog, and ulnar attachment), carpal ligaments (scapholunate [SL] and lunotriquetral [LT] ligaments), intercarpal cartilage, and median and ulnar nerves. Mean values and standard deviations of evaluation results were calculated for each sequence. Participants' experience in undergoing t...
Poster: "ESSR 2013 / P-0004 / Feasibility study of high resolution imaging of cartilage of t... more Poster: "ESSR 2013 / P-0004 / Feasibility study of high resolution imaging of cartilage of the CMC1 joint at 7Tesla MRI" by: "M. A. Korteweg1, F. Visser2, P. Chernohorsky1, S. D. Strackee1, P. Luijten2, M. Maas1, D. W. J. Klomp2; 1Amsterdam/NL, 2Utrecht/NL"
Poster: "ESSR 2012 / P-0105 / Feasibility study of high resolution PDw imaging of cartilage ... more Poster: "ESSR 2012 / P-0105 / Feasibility study of high resolution PDw imaging of cartilage of the ankle at 7Tesla MRI " by: " M. A. Korteweg 1, F. Visser2, M. Italiaander2, P. Luijten2, M. Maas1, D. W. J. Klomp2; 1Amsterdam/NL, 2Utrecht/NL"
technique which is widely available and less time consuming. Patients who are positive on AUS gui... more technique which is widely available and less time consuming. Patients who are positive on AUS guided FNAC can proceed for ALND directly thereby obviating the need for SNB.
Ultra-high field 7Tesla (7T) MRI offers important advantages for oncological practice. Due to the... more Ultra-high field 7Tesla (7T) MRI offers important advantages for oncological practice. Due to the high field strength, new opportunities have arisen for the imaging of cancer. The newly acquired ultra-high resolution facilitates the possibility of detailed anatomical imaging. Also molecular processes can now be visualized in greater detail. This allows structured imaging of the metabolism of a malignant process. The first in vivo results from patients with prostate-and breast cancer demonstrated that 7T imaging with high spatial and spectral resolution is indeed feasible. Additionally at high field strengths other scanning techniques can be applied than at lower field strengths. Such techniques can accurately detect calcifications in breast cancer, for example. 7T MRI has the potential of performing quantitative molecular imaging and personalized assessment of cancer patients and will play a part in the early diagnosis, tumor characterization and therapy monitoring of malignant lesions.
In diagnosing osteochondral defects, MRI and CT have similar diagnostic accuracies. CT is faster,... more In diagnosing osteochondral defects, MRI and CT have similar diagnostic accuracies. CT is faster, better for preoperative planning, cheaper and allows the ankle to be depicted in various anatomical positions in a 3D manner. CT enables clear delineation of the true osteochondral defect, will not overcall the size due to bone marrow edema (as seen on MRI), and helps assessing the extent of the osseous defect in the presence of cystic defects.
Objective To determine the sensitivity and specificity of 3.0-tesla (T) magnetic resonance imagin... more Objective To determine the sensitivity and specificity of 3.0-tesla (T) magnetic resonance imaging (MRI) and a dedicated hand coil in diagnosing scapholunate ligament (SLL) injury compared with intraoperative findings. Methods From January 2006 until September 2010, 3.0-T MRI scans were performed on 38 wrists (37 patients) with clinically unclear but suspected lesions of the SLL. These scans were evaluated by two experienced radiologists. Radiological findings were compared with intraoperative findings during arthrotomy. Sensitivity, specificity, accuracy, and positive and negative predictive value were calculated. Results An SLL lesion was identified during arthrotomy in 37 wrists. The first radiologist identified an SLL lesion on MRI in 26 wrists, all of which were confirmed intraoperatively. The second radiologist identified SLL lesions in 31 patients; however, intraoperatively it was found that there was no lesion of the ligament in one patient. Sensitivity ranged from 70 to 81% with a specificity of 100% and a positive predictive value of 97 to 100%. Accuracy measured 71 to 79%. Conclusions 3.0-T MRI of the wrist is moderately sensitive and very specific for detection of SLL lesions. However, if there is a high clinical suspicion of an SLL rupture, a 3.0-T MRI does not often have an additional value. Level of Evidence Diagnostic, level II
Here we describe our first experience with contrast-enhanced (CE) MRI of breast cancer at 7 tesla... more Here we describe our first experience with contrast-enhanced (CE) MRI of breast cancer at 7 tesla (T), compared to 3T and histopathology. A 52 year old female patient with a mammographically suspicious breast mass (BI-RADS V) underwent 7 T CE-MRI. Results were described according to the BI-RADS-MRI criteria and compared to 3T and histopathology. After contrast administration, a homogeneously enhancing, irregular spiculated mass was depicted at both 3T and 7 T; sizes were identical. The most malignant kinetic curve was characterized by a rapid initial rise followed by a wash-out pattern in the delayed phase, i.e. a type 3 curve, at both field strengths. Even though T1-effects of contrast agents are suggested to be reduced at higher fields, quantification of contrast enhancement-to-noise ratio showed a ratio of 4.6 at 7 T and 2.8 at 3T when comparing contrast-to-noise of the mass before and after contrast administration. Both examinations, using a single dose of gadolinium-based contrast agent, achieved good image quality. Final histopathological evaluation showed an invasive ductulolobular carcinoma with an intraductal component. This initial experience suggests that clinical contrast-enhanced 7 T MRI of the breast is technically feasible and may allow BI-RADS-conform analysis.
Journal of magnetic resonance imaging : JMRI, 2012
To determine lipid composition of excised healthy and metastatic sentinel lymph nodes of breast c... more To determine lipid composition of excised healthy and metastatic sentinel lymph nodes of breast cancer patients, as lipids are a potential discriminatory marker for malignancy.
Objective To characterize ex vivo healthy human axillary lymph nodes on 7 Tesla MRI and to correl... more Objective To characterize ex vivo healthy human axillary lymph nodes on 7 Tesla MRI and to correlate the findings with pathological analysis as a first step towards non-invasive staging of breast cancer patients in the future. Methods Four axillary lymph node dissection (ALND) specimens from 2 autopsy patients, who had no cancer, were examined on a clinical 7 Tesla MRI system. For morphological analysis a 3D T1-weighted fat-suppressed fast-field-echo [isotropic resolution 180 μm] was acquired. For quantitative analyses 2D T1-, 3D T2-, T2*-and diffusion-weighted images were acquired. The ALNDs were mapped and stained for precise correlation of MRI to pathology. Nodes were sliced in 3 μm sections, Haematoxylin & Eosin stained, and examined by an experienced pathologist. Results MRI detected all 45 nodes and 6 additional nodes that were not detected at pathological analysis. B-cell follicles, efferent-and afferent lymph vessels and blood vessels were identified. Mean T1, T2, T2*, ADC values (± standard deviation) were 944±113 ms, 32±2 ms, 16± 2 ms, 0.39±0.09•10 −3 mm 2 /s, respectively. Conclusions 7 Tesla MRI of ex vivo human axillary lymph nodes correlated well with pathology. MRI detected all nodes present in the specimens and allowed visualization of fine structural detail. Pathology-correlated quantitative MRI data are presented.
To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultra... more To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (DUS) could replace digital subtraction angiography (DSA) for diagnosing internal carotid artery (ICA) stenosis in regional centres with less specialized technicians and equipment, such as a 1 Tesla MRI machine. MATERIALS AND METHODS: Sixty-six consecutive, symptomatic patients with ICA stenosis, as evidenced using DSA, were included. In the first 34 patients DUS was validated and cutoff criteria were established. Data were analysed by receiver operating characteristic curve and logistic regression. Two observers analysed the DUS and CE-MRA results of 32 patients. Stenoses were categorized in accordance with North American Symptomatic Endarterectomy Trial (NASCET) measurement criteria. RESULTS: Peak systolic velocity (PSV) in the ICA was defined as a better parameter for defining stenosis than end diastolic velocity and the PSV ICA:common carotid artery ratio. The optimal PSV threshold was 230 cm/s. Four ICAs were not interpretable on DUS, and one on CE-MRA. Two patients did not undergo CE-MRA. The sensitivities and specificities were calculated: for DUS these were 100% and 68% respectively; for observer 1 on CE-MRA these were 93% and 89%, respectively; for observer 2 these were 92% and 87%, respectively. The sensitivity and specificity for combined DUS/CE-MRA were 100% and 85%, respectively. Seventy-eight percent of CE-MRA and DUS correlated. The weighted Kappa for CE-MRA and DSA were 0.8 and 0.9, respectively. CONCLUSION: DUS and CE-MRA are effective non-invasive methods for selecting patients with ICA stenosis for carotid endarterectomy in non-specialized centres using a 1 T machine. The present results suggest that no referrals to more specialized centres for non-invasive diagnostic work-up for carotid artery stenoses will be necessary.
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Papers by Mies Korteweg