| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Original Research |
1 Institute of Clinical Radiology, University Hospital Grosshadern,
Ludwig–Maximilian–University Munich, Marchioninistrasse 15, 81377
Munich, Germany.
2 Department of Haemato-Oncology, University Hospital Grosshadern,
Ludwig–Maximilian–University Munich, Munich, Germany.
Received June 4, 2007;
accepted after revision October 30, 2007.
Address correspondence to A. Baur-Melnyk
(andrea.baur{at}med.uni-muenchen.de).
Abstract
 Top Abstract IntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
SUBJECTS AND METHODS. Forty-one patients with histologically confirmed myeloma were prospectively examined with a whole-body MDCT protocol and whole-body MRI on a 1.5-T system. The MRI protocol consisted of T1-weighted spin-echo and STIR sequences. For data analysis, the entire skeleton was divided into 61 regions per patient. Image evaluation was performed in a consensus reading by two radiologists blinded to the patients' history, with separate evaluation of each technique. The patients were staged by MRI and MDCT data separately according to the Durie and Salmon PLUS staging system.
RESULTS. On MRI, 15 patients showed no involvement. In 26 patients, 975 regions were affected: 21 patients were stage I, two were stage II, and 18 were stage III. On MDCT, 19 patients showed no involvement. In 22 patients, 462 regions were affected. For the detection rate, MRI was statistically superior to MDCT (p < 0.001, Wilcoxon's signed rank test). According to MDCT, 25 patients were stage I, seven were stage II, and nine were stage III. In 21 patients with involvement detected on both methods, MRI showed more extensive disease than MDCT. Eleven patients were understaged with MDCT compared with MRI, which was statistically significant (p < 0.001, chi-square test).
CONCLUSION. Whole-body MDCT leads to a significantly lower detection rate and staging in patients with multiple myeloma.
Keywords: bone marrow • MDCT • MRI • multiple myeloma • whole-body imaging
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
|
In many institutions, radiography of the entire skeletal system is still used in routine clinical practice. Multiple myeloma results in geographic bone destruction or diffuse heterogeneous osteopenia, which may be difficult to differentiate from perimenopausal and senile osteoporosis. In several studies comparing the sensitivity of radiography and MRI in the detection of bone involvement in multiple myeloma, radiography was associated with a false-negative rate of 30–70%, so that the extent of skeletal involvement was significantly underestimated [8–10].
Because the value of MRI for a sensitive detection and the prognostic significance of bone marrow infiltrations were clearly shown, Durie and coworkers [11] introduced the Durie and Salmon PLUS staging system, which includes whole-body MRI as a diagnostic tool (Appendix 1). However, because of the lack of suitable MRI scanners, whole-body MRI is not always available. In addition, the costs for whole-body MRI are not always covered by health care insurance. With the relative widespread availability of MDCT, whole-body MDCT was proposed as an alternative method for high-resolution screening of the whole skeleton in patients with multiple myeloma. Our aim was to compare the detection rate of skeletal myeloma involvement on MRI and MDCT for the staging of patients with newly diagnosed multiple myeloma.
|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
MDCT Protocol
All patients were examined with a 16- or a 64-MDCT scanner (Somatom
Sensation 16 or 64, Siemens Medical Solutions). A 16 x 0.75 mm
collimation with a pitch of 1 or 2 was chosen with a 0.5 second rotation time,
constant tube voltage of 120 kV, and tube time current mAs product of 100
using the Care-Dose program (Siemens Medical Solutions). The mean effective
dose was 3.95 mSv, which was calculated using the software CT-Expo (Nagel
& Schramm). The area scanned ranged from the skull to the knees, with the
scan length adapted to the patient's height ranging between 1,024 and 1,540
mm. The scanning time was approximately 1 minute. For image reconstruction, a
sharp convolution kernel (B 70f) was used. All scans were reconstructed in the
axial plane with an effective slice thickness of 3 mm and a reconstruction
increment of 3 mm. In addition, multiplanar reformations (MPRs) in the
sagittal plane for the entire spine (section thickness, 3 mm), in the coronal
plane for the skull and thorax, and a second coronal reconstruction for the
pelvis including both femurs (section thickness, 3 mm) were obtained. The MPRs
were performed using the standard software provided with the scanner (Siemens
Workflow 3D, Siemens Medical Solutions)
(Fig. 1).
MRI Protocol
The MRI examinations were performed on a 1.5-T system (Symphony or Avanto,
Siemens Medical Solutions). In the Symphony scanner, the patient was
positioned feet first (supine), using the leg coil and the body-array-coil,
for the examination of the pelvic region and the legs, respectively.
T1-weighted spin-echo (TR/TE, 541/13; field of view, 480 mm; thickness, 5.0
mm) and fast STIR (2,680/101; field of view, 480 mm; thickness, 5.0 mm)
sequences were performed in coronal orientation. Then, the patients were
repositioned to head first (supine), using a head-and-neck coil and two
body-array coil sets covering the thorax. The head was examined in the axial
plane (T1-weighted spin-echo: 416/17; field of view, 250 mm; thickness, 5.0
mm, and STIR, 6,100/108) and the thorax and shoulder girdle in the coronal
plane (T1-weighted spin-echo: 517/13; field of view, 480 mm; thickness, 7.0 mm
and STIR: 2,680/101; field of view, 480 mm; thickness, 7.0 mm). The spine was
imaged in two steps in sagittal orientation for the cervical and the upper
thoracic spine and the lower thoracic spine and the lum bar spine,
respectively (T1-weighted spin-echo: 450/12; field of view, 450 mm; thickness,
3.0 mm and STIR: 4,290/59; field of view, 450 mm; thickness, 3.0 mm).
In the Avanto scanner, the total imaging matrix system (TIM) (Siemens Medical Solutions) was used to cover the whole skeleton using 5 surface coils including the fixed spine array coil. T1-weighted spin-echo (630/12; field of view, 480 mm; thickness, 5.0 mm) and fast STIR (4,810/84; inversion time, 170 milliseconds; field of view, 480 mm; thickness, 5.0 mm) sequences were performed with coronal orientation of the pelvis and the legs, respectively. The legs were examined in the coronal plane with T1-weighted spin-echo (504/12; field of view, 480 mm; thickness, 5.0 mm) and STIR sequences (3,850/84; inversion time, 170 milliseconds; field of view, 480 mm; thickness, 5.0 mm). The head was examined in the axial plane (T1-weighted spin-echo: 575/11; field of view, 230 mm; thickness, 5.0 mm and STIR: 6,980/118; inversion time, 180 milliseconds; field of view, 230 mm; thickness, 5.0 mm). The thorax and shoulder girdle were also examined in the coronal orientation using a breath-hold technique (T1-weighted spinecho: 431/8.2; field of view, 480 mm; thickness, 5.0 mm and STIR: 3,170/101; inversion time, 170 milliseconds; field of view, 480 mm; thickness, 5.0 mm). In addition, the thorax was scanned in the axial plane (STIR: 3,200/100; inversion time, 170 milliseconds; field of view, 380 mm; thickness, 5.0 mm). The spine was imaged in two steps in the sagittal orientation for the cervical and the upper thoracic spine and the lower thoracic spine and the lumbar spine, respectively (T1-weighted spinecho: 450/11; field of view, 400 mm; thickness, 3.0 mm and STIR: 5,800/54; inversion time, 180 milliseconds; field of view, 400 mm; thickness, 3.0 mm). For the acquisition of the thorax, respiratory gating using a navigator technique was performed. The mean in-room time was approximately 50 minutes for the Symphony scanner and 40 minutes for the Avanto scanner (Fig. 2).
|
|
On MDCT, inhomogeneous osseous destructions or focal osteolyses with soft-tissue density larger than 5 mm in diameter were recorded as focal myeloma involvement. In tubular bones, diffuse increase in density (soft-tissue density) was recorded as marrow involvement. In the ribs, focal osteolyses with or without expansile character and soft-tissue density was defined as rib involvement.
The number of foci was counted up to 20. More than 20 foci were registered as "multifocal (> 20)." In case both MRI and MDCT showed involvement, it was assessed whether MRI or MDCT showed a greater extent of disease. At first, the MDCT data sets of each patient were read and evaluated. Six weeks later, the MRI datasets of each patient were evaluated separately. This type of reading was chosen to control the memory effect.
Depending on the number of lesions or the grade of diffuse disease, the patients were staged according to the radiologic criteria of the Durie and Salmon PLUS staging system [11]. Statistics were performed with the STATISTICA program, release 7.1 (StatSoft). The detection rate with MRI and MDCT was compared using the Wilcoxon's signed rank test. The difference for staging was evaluated by the chi-square test. A level of < 0.05 was considered significant.
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
|
On MDCT, 19 patients showed no involvement. In 22 patients, 462 regions were affected by myeloma. Nine patients showed multifocal disease. According to the Durie and Salmon PLUS staging system, 25 patients were stage I, seven were stage II, and nine were stage III (Table 2).
|
Fifteen patients showed concordantly no involvement in both techniques. Four patients exhibited concordant involvement in both techniques. These four patients had focal involvement (Figs. 3A, 3B, and 3C). In 21 patients with involvement in both methods, MRI revealed more extensive disease than MDCT (Figs. 4A, 4B, 4C, 5A, 5B, 5C, 5D, and 5E). Seven of these patients had a focal pattern of involvement, 13 a combined diffuse and focal pattern of involvement, and one a diffuse infiltration pattern. One patient showed more extensive disease on MDCT. Four patients were stage I on MDCT and stage II (n = 2) or stage III (n = 2) on MRI. Two of these patients had histologically proven intermediate diffuse disease in the bone marrow; one patient had multifocal disease with multiple small foci and the other had proven intermediate diffuse disease plus one focal tumor nodule in the second lumbar vertebral body. The lower detection rate for myeloma involvement on MDCT compared with MRI was statistically significant (p < 0.001).
|
|
|
|
|
|
|
|
|
|
|
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
MRI has also been proven in prior studies to be a strong prognostic parameter. In a survival analysis, the extent of infiltration in spinal MRI was highly associated with prognosis of the patients [4]. The time to progression in patients with stage I disease and normal MRI has been reported to be significantly longer (44 months) than in patients with stage I disease and MRI abnormalities (11 months) [3]. Patients with abnormal MRI had lower 5-year survival rates (30%) than patients with normal MRI (80%) [16]. Also, in populations stratified according to laboratory risk factors, MRI added prognostic value, increasing time to progression from 21 months (abnormal MRI) to 57 months (normal MRI) in a population with intermediate laboratory risk factors [17].
In two studies, the sensitivity for detecting myeloma manifestations in radiographs and CT was analyzed. In 1985, Schreiman et al. [18] showed in 32 myeloma patients that CT is more sensitive than radiography. In six of 13 patients the radiographs were normal despite myeloma involvement detected on CT; in 12 patients, CT showed more extensive disease. In the study of Mahnken et al. [19] on 18 patients, 4-MDCT of the spine and pelvis was superior to radiography. MDCT detected 24 additional lesions, 15 additional fractures, and six vertebral bodies at risk for fracture.
From these studies, it is evident that cross-sectional imaging should
replace radiography of the skeleton, if available. Because myeloma lesions may
occur at any site in the skeleton, there is a need for whole-body imaging.
With new scanning approaches and coil systems, whole-body MRI has been made
feasible at a reasonable expenditure of time
[20]
(Fig. 2). With the introduction
of 16- and 64-MDCT scanners, a whole-body approach also became feasible for CT
(Fig. 1). Ionizing radiation is
a disadvantage of MDCT over MRI. Radiation dose with a low-dose protocol in
MDCT is only slightly more than the radiation dose of a skeletal survey with
X-rays (
3–4 mSv depending on patient weight). In addition, in
tumor patients with a mean survival of 3–5 years, chemotherapy and
radiation considerations play only a minor role. However, of course, according
to the as low as reasonably achievable (ALARA) principle, radiation exposure
should be kept as low as possible.
Up to now, to our knowledge, whole-body MDCT has not been compared with whole-body MRI in patients with multiple myeloma. In our study, whole-body MRI showed significantly more extensive disease than whole-body MDCT (Figs. 4A, 4B, 4C, 5A, 5B, 5C, 5D, and 5E). The reason for the higher sensitivity of MRI is the direct assessment of the bone marrow components: fat and water bound protons. Infiltration of the bone marrow by neoplastic cells results in displacement of fat cells. Focal tumor cell accumulations are visualized as focal areas of low signal intensity on T1-weighted spin-echo images and high signal intensity on STIR im ages. In MDCT, the result of tumor infiltration can be visualized. However, it takes some time before the osteoclastic activity of myeloma cells leads to bone destruction. For those reasons, in early focal marrow infiltration by myeloma without significant trabecular destruction, MDCT may be negative.
Many false-negative MDCT findings were obtained in cases with diffuse marrow infiltration. This may be because diffuse infiltration leads to interstitial infiltration of the bone marrow, which is not necessarily associated with destruction of trabecular or cortical bone. If diffuse infiltration progresses and osteoclast-activating factors are released, the result is osteoporosis, which can be misdiagnosed as senile osteoporosis on MDCT. Neoplastic infiltration in the long bones without or with the little trabecular bone can be recognized because of the replacement of fatty marrow by soft tissue. Therefore, it is always important to view these areas in a soft-tissue window setting and to perform density measurements. It must be kept in mind that early (2–3 months) after systemic chemotherapy or stem-cell transplantation, bone marrow hyperplasia can appear similarly to diffuse bone marrow infiltration.
Because of the lower detection rate of myeloma lesions with MDCT compared with MRI, MDCT resulted in significant understaging in patients with myeloma. Altogether, 11 patients were understaged using whole-body MDCT compared with MRI. Seven of 11 patients were understaged concerning stage II versus stage III. Four of 11 patients were understaged concerning stage I (no treatment) versus stage II or III (treatment indication).
In conclusion, recent technical developments in MRI and the introduction of 16- and 64-MDCT scanners offer the possibility for whole-body imaging of the complete skeleton in patients with multiple myeloma. MDCT enables thin collimation and high-resolution imaging of cortical and trabecular bone within an acquisition time of about 1 minute. This is a major advantage in comparison with the skeletal survey with radiographs and MRI, which takes about 40–50 minutes. However, MRI results in a significantly higher detection rate for both focal and diffuse disease, which is mainly due to the display of bone marrow components and marrow replacement by neoplastic cells.
In comparison with MRI, a considerable number of patients would have been understaged using MDCT alone. Therefore, if available, whole-body MRI should be used as the first-line imaging method. In cases with involvement in MRI, MDCT with reformats or X-rays should be performed to judge osteolytic destructions and fracture risk. In patients without any detectable involvement in MRI, no further imaging is required because MRI, to date, is the most sensitive method for detecting skeletal involvement in patients with multiple myeloma.
|
TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
|---|
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  T. Bauerle, J. Hillengass, K. Fechtner, C. M. Zechmann, L. Grenacher, T. M. Moehler, H. Christiane, W.-G. Barbara, K. Neben, H.-U. Kauczor, et al. Multiple Myeloma and Monoclonal Gammopathy of Undetermined Significance: Importance of Whole-Body versus Spinal MR Imaging Radiology, August 1, 2009; 252(2): 477 - 485. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Lin, A. Luciani, K. Belhadj, P. Maison, A. Vignaud, J.-F. Deux, P. Zerbib, F. Pigneur, E. Itti, H. Kobeiter, et al. Patients with Plasma Cell Disorders Examined at Whole-Body Dynamic Contrast-enhanced MR Imaging: Initial Experience Radiology, March 1, 2009; 250(3): 905 - 915. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
