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Clinical Pediatric Imaging Pediatric Imaging Clinical MR Tumor Staging for 1A 1B Treatment Decision in Case of Wilms Tumor G. Schneider, M.D., Ph.D.; P. Fries, M.D. Dept. of Diagnostic and Interventional Radiology, Saarland University Hospital, Homburg/Saar, Germany 1C 1D Introduction Patient history Nephroblastoma – also known as Wilms tumor – is the most frequent renal Europe or COG (Children’s Oncology Group) in North America. Therapy A 4-year-old girl presented with a large palpable mass in the left upper quadrant * malignancy in childhood with the high- includes primary surgery (COG), pre- and unspecific abdominal pain. Ultra- est incidence of this tumor within the fourth year of life. 80% of patients are operative chemotherapy (SIOP), and/or adjuvant chemotherapy. If not treated, sound had already revealed a large tumor of the left hemiabdomen with + less than 5 years old, however it is a rare prognosis of a Wilms tumor is poor. mass effect towards the liver. The condition in neonates (<1%). Independent of prognostic factors such patient was referred to our MRI depart- In general, there are no known risk fac- as stage and grading, the overall out- ment because of suspicion of Wilms tors for the development of nephroblas- come is good and approximately 90% of tumor. toma, but it may be associated with rare all children will be cured. conditions like Denys-Drash (triad of Questions for imaging are: a) supporting MRI protocol congenital nephropathy, Wilms tumor the suspicion of a Wilms tumor for initia- MRI was conducted using a 1.5 Tesla and intersex disorders), WAGR (also tion of therapy, b) evaluation of tumor MAGNETOM Aera with the combination 1E 1 Transversal high-resolution T2w images showing the called Wilms tumor-aniridia syndrome) volume, c) contralateral tumor manifes- of the 18-channel body coil and the inte- Wilms tumor (*) and multiple lung metastases (arrows). and Beckwidth-Wiedeman (giantism tation and d) lymph nodes metastasis grated spine coil. For the MRI procedure Due to the space occupying aspect of the large tumor, the associated with tumors and malforma- or infiltration of neighboring structures the patient received an intravenous residual kidney is swollen (+) and also slight edema of the tions) syndrome. The incidence is approx. 1: 100,000 for western coun- e.g. diaphragm or liver. Tumor staging has to include at least the sedation using propofol. The imaging protocol included diffusion-weighted * liver hilum can be seen (arrowheads). tries including the US, while a lower whole abdomen and thorax (lung filiae imaging (DWI, syngo REVEAL), acquired incidence is reported for Asian countries. are the most common presentation of during free breathing, and transversal If not associated with a syndrome, clini- metastatic disease). Imaging modalities T2w TSE and HASTE sequences with cal symptoms – if present at all – are used are ultrasound, MRI, and CT in case navigator triggering. very often unspecific and abdominal of lung metastases. Depending on final A single-shot echo planar diffusion pain and palpable tumor can be the only tumor histology, a bone (often scinti- imaging with Stejskal-Tanner diffusion findings at the time of diagnosis. gram) and brain MRI scan have to be encoding scheme was applied. For MRI is considered the imaging modality performed in case of CCSK (clear cell sar- fat saturation, an inversion recovery of choice for tumor staging and subse- coma) and RTK (rhabdoid tumor of the technique was used. The sequence quent treatment planning. If imaging is kidney), too. MRI is recommended inde- parameters were: conclusive, often no biopsy is performed pendent of the above-mentioned reasons prior to initiation of therapy. Clinical in any case where a) a caval vein tumor treatment is according to protocols of thrombus, b) infiltration of liver and dia- SIOP (Society of Pediatric Oncology) in phragm, or c) continuous tumor exten- sion into the thoraxic cavity is suspected. Continued on page 10 6 MAGNETOM Flash · 3/2010 · www.siemens.com/magnetom-world MAGNETOM Flash · 3/2010 · www.siemens.com/magnetom-world 7 Clinical Pediatric Imaging Pediatric Imaging Clinical 2 5A 5B 2 Rotating MIP based on high b-value images. 5C 5D 3A 3B 3C 3D 3E 3F 3G 5E 5F 3 (A) Coronal DWI MIP. Original b-value images at 0 and 800 s/mm2 (B, C and E, F) as well as calculated b-value at b 1400 s/mm2 (D, G) are shown. (Arrows pointing to lung metastases.) 4A 4B * * * 5 Based on ADC maps and high b-value images (b 1400 s/mm2 is shown), a clear differentiation between residual but swollen kidney 4 Calculated ADC map (A) and corresponding T2w image (B) demonstrating the tumor heterogeneity. The area marked by the arrows has a clear tissue (arrows) and the Wilms tumor (arrowhead) is possible. Both types of tissue differ in their cellular density, however, on T2w images restriction in diffusibility but based on T2w imaging alone, no differentiation between this area and the one marked with * is possible. While the no clear differentiation is possible in this case (compare Fig. 1). Nevertheless, not all areas of the tumor are characterized by high signal high signal area on T2w and high ADC values may represent cysts or calceal dilation, the area with the high restriction of diffusion represents a on the very high b-value images, demonstrating well the tumor heterogeneity. (A, B) ADC maps. (C, D, E) b 1400 s/mm2 images. (F) Coro- very densely packed areal e.g. mucous tumor cells. nal thick-slice MPR based on b 1400 s/mm2 images (* spleen). 8 MAGNETOM Flash · 3/2010 · www.siemens.com/magnetom-world MAGNETOM Flash · 3/2010 · www.siemens.com/magnetom-world 9 Clinical Pediatric Imaging Pediatric Imaging Clinical 6A 6B 7A 7B 7 Follow-up examination with CT (A) still showing a small residual lung metastasis (arrow), which can also be visualized by MRI (B). The main tumor is also clearly reduced in its mass after first cycle of chemotherapy (C–F) in caudo- cranial sorting. 7C 7D 6 Corresponding images of the initial ultrasound examination of the Wilms tumor in sagittal (A) and transversal (B) orientation are shown. Continued from page 6 Imaging ﬁndings TR 15400 ms, TE 75 ms, TI 180 ms, PAT A large occupying tumor deriving from displaced spleen is also within normal factor of 2, 3-scan trace (averaged), FOV the lower pole of the left kidney with age-related range. 309 x 380, matrix 208 x 128 (interpo- compression of the residual kidney and On a follow-up study after chemotherapy lated to 208 x 256), slice thickness 5 mm, mass effect towards the liver and espe- and before surgery a tremendous reduc- 7E 7F no gap, 4 averages. Real voxel size was cially the left liver lobe is shown. Due to tion of tumor size can be noticed. Only 1.5 x 3 x 5 mm3. Two b-values at b 0 and the mass effect, slight edema of the liver small residual tumor tissue of one lung b 800 s/mm2 were acquired. ADC maps hilus can be seen. However, the border metastases is visible on CT and MRI. and additional high b-value images at of the mass is well circumscribed and no b 1400 s/mm2 were calculated auto- evidence of diffuse tumor infiltration of Conclusion matically by the scanner software, based the liver, spleen or diaphragm can be Whole-body imaging in staging of Wilms on linear signal decay. DWI covered the seen. Since no encasement of retroperi- tumor can replace CT imaging and gives whole body trunk from skull base toneal vessels or other structures is seen all necessary information for therapy towards upper lower extremities. Acqui- DD of neuroblastoma can be ruled out. planning. With the help of newer imag- sition time was approx. 15 min. For pre- Also the lumen of the abdominal aorta is ing modalities in MRI, especially DWI, sentation and fast overview about tumor regular and neither a tumor infiltration the prediction of tumor response needs spread, a rotating maximum intensity of the large vessels nor a tumor-throm- to be evaluated. This can easily be done projection (MIP) based on b 800 s/mm2 bus can be visualized. The right kidney by correlating histological data with was generated. and the other abdominal organs are free imaging data from patients enrolled in For detailed morphology and assess- of metastases. However, already well prospective clinical trials. As preopera- ment of tumor infiltration, navigator visualized by the MIP DWI, a large tumor tive chemotherapy is only part of the triggered T2w TSE was applied for the mass at the right lung hilum can be seen SIOP studies such investigations can pre- References Contact 1 Kaste, S.C., Dome, J.S., Babyn, P.S., Graf, N.M., abdomen including the lower thorax and with compression of central lung struc- dominantly be performed in Europe. PD Dr. Dr. Günther Schneider Grundy, P., Godzinski, J., Levitt, G.A., Jenkinson, mediastinum. Sequence parameters were tures and edema of the depending lung H. 2008 Wilms tumour: Prognostic factors, stag- Dept. of Diagnostic and Interventional TR 3508 ms, TE 102 ms, 2 averages. tissue. In addition, at least four addi- Radiology ing, therapy and late effects Pediatric Radiology Saarland University Hospital PAT factor 2, FOV 188 x 250 mm2, matrix tional lung metastases are detected. 38 (1), pp. 2-17. Kirrberger Strasse 269 x 512, slice thickness 6 mm, 20% No evidence for bone metastases. The 2 Graf, N., Tournade, M.-F., De Kraker, J. 2000 The 66421 Homburg/Saar role of preoperative chemotherapy in the manage- gap, acquisition time was approx. 8 min. bright signal of the bone marrow on Germany ment of Wilms’ tumor: The SIOP studies. Urologic high b-value images has to be con- email@example.com Clinics of North America 27 (3), pp. 443-454. sidered as age related. The size of the 10 MAGNETOM Flash · 3/2010 · www.siemens.com/magnetom-world MAGNETOM Flash · 3/2010 · www.siemens.com/magnetom-world 11
"MR Tumor Staging for Treatment Decision in Case of Wilms Tumor"