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DW-MRI of the urogenital tract: applications in oncology.

Petralia G, Thoeny HC - Cancer Imaging (2010)

Bottom Line: Promising results were also published for the detection of prostate cancer.DW-MRI may improve the performance of conventional T2-weighted and contrast-enhanced MRI in the preoperative work-up of bladder cancer, as it may help in distinguishing superficial from muscle invasive bladder cancer, which is critical for patient management.Another challenging application of DW-MRI in the urogenital tract is the detection of pelvic lymph node metastases.

View Article: PubMed Central - PubMed

Affiliation: Institute of Diagnostic, Pediatric and Interventional Radiology, University Hospital of Bern, Inselspital, Freiburgstrasse 10, Bern, Switzerland.

ABSTRACT
Diffusion-weighted magnetic resonance imaging (DW-MRI) appears to hold promise as a non-invasive imaging modality in the detection of early microstructural and functional changes of different organs. DW-MRI is an imaging technique with a high sensitivity for the detection of a large variety of diseases in the urogenital tract. In kidneys, DW-MRI has shown promise for the characterization of solid lesions. Also in focal T1 hyperintense lesions DW-MRI was able to differentiate hemorrhagic cysts from tumours according to the lower apparent diffusion coefficient (ADC) values reported for renal cell carcinomas. Promising results were also published for the detection of prostate cancer. DW-MRI applied in addition to conventional T2-weighted imaging has been found to improve tumour detection. On a 3 T magnetic resonance unit ADC values were reported to be lower for tumours compared with the normal-appearing peripheral zone. The combined approach of T2-weighted imaging and DW-MRI also showed promising results for the detection of recurrent tumour in patients after radiation therapy. DW-MRI may improve the performance of conventional T2-weighted and contrast-enhanced MRI in the preoperative work-up of bladder cancer, as it may help in distinguishing superficial from muscle invasive bladder cancer, which is critical for patient management. Another challenging application of DW-MRI in the urogenital tract is the detection of pelvic lymph node metastases. As the ADC is generally reduced in malignant tumours and increased under inflammatory conditions, reduced ADC values were expected in patients with lymph node metastases.

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Related in: MedlinePlus

Qualitative analysis of the common patterns in DW-MRI, using high b value images and corresponding ADC maps in grey scale (colour shades of light grey correspond to higher ADC values, whereas colour shades of dark grey correspond to lower ADC values). Boxes in white indicate high signal intensity on high b value images and high ADC values. Boxes in black indicate low signal intensity on high b value images and low ADC values.
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Figure 3: Qualitative analysis of the common patterns in DW-MRI, using high b value images and corresponding ADC maps in grey scale (colour shades of light grey correspond to higher ADC values, whereas colour shades of dark grey correspond to lower ADC values). Boxes in white indicate high signal intensity on high b value images and high ADC values. Boxes in black indicate low signal intensity on high b value images and low ADC values.

Mentions: The easiest method to avoid misinterpretation because of the T2 shine-through effect is to compare the high b value DW-MR image with the corresponding ADC map[10]. A tissue with a significant T2 shine-through effect typically shows high signal intensity on the high b value image, but returns a high ADC value, displayed in colour shades of light grey on the corresponding ADC maps (Fig. 1). Such a combined interpretation of DW-MR images and ADC maps is therefore strongly advocated for the urogenital tract, leading to a new radiological interpretation of lesions. High signal intensity on the high b value DW-MR images and colour shades of dark grey on ADC maps indicate a cellular tissue, including malignancy within the differential diagnosis (Fig. 2); however, abscesses might also be cellular, with similar appearance. When a lesion shows low signal intensity in low b value images and colour shades of light grey on ADC maps, it is mostly related to cystic or necrotic components (Fig. 2). When a lesion shows low signal intensity on high b value DW-MR images and colour shades of dark grey on the ADC maps in grey scale, some conditions could be considered, including suppressed macroscopic fatty tissue, as well as susceptibility artefacts (e.g. iron deposition) (Fig. 3).Figure 1


DW-MRI of the urogenital tract: applications in oncology.

Petralia G, Thoeny HC - Cancer Imaging (2010)

Qualitative analysis of the common patterns in DW-MRI, using high b value images and corresponding ADC maps in grey scale (colour shades of light grey correspond to higher ADC values, whereas colour shades of dark grey correspond to lower ADC values). Boxes in white indicate high signal intensity on high b value images and high ADC values. Boxes in black indicate low signal intensity on high b value images and low ADC values.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2967148&req=5

Figure 3: Qualitative analysis of the common patterns in DW-MRI, using high b value images and corresponding ADC maps in grey scale (colour shades of light grey correspond to higher ADC values, whereas colour shades of dark grey correspond to lower ADC values). Boxes in white indicate high signal intensity on high b value images and high ADC values. Boxes in black indicate low signal intensity on high b value images and low ADC values.
Mentions: The easiest method to avoid misinterpretation because of the T2 shine-through effect is to compare the high b value DW-MR image with the corresponding ADC map[10]. A tissue with a significant T2 shine-through effect typically shows high signal intensity on the high b value image, but returns a high ADC value, displayed in colour shades of light grey on the corresponding ADC maps (Fig. 1). Such a combined interpretation of DW-MR images and ADC maps is therefore strongly advocated for the urogenital tract, leading to a new radiological interpretation of lesions. High signal intensity on the high b value DW-MR images and colour shades of dark grey on ADC maps indicate a cellular tissue, including malignancy within the differential diagnosis (Fig. 2); however, abscesses might also be cellular, with similar appearance. When a lesion shows low signal intensity in low b value images and colour shades of light grey on ADC maps, it is mostly related to cystic or necrotic components (Fig. 2). When a lesion shows low signal intensity on high b value DW-MR images and colour shades of dark grey on the ADC maps in grey scale, some conditions could be considered, including suppressed macroscopic fatty tissue, as well as susceptibility artefacts (e.g. iron deposition) (Fig. 3).Figure 1

Bottom Line: Promising results were also published for the detection of prostate cancer.DW-MRI may improve the performance of conventional T2-weighted and contrast-enhanced MRI in the preoperative work-up of bladder cancer, as it may help in distinguishing superficial from muscle invasive bladder cancer, which is critical for patient management.Another challenging application of DW-MRI in the urogenital tract is the detection of pelvic lymph node metastases.

View Article: PubMed Central - PubMed

Affiliation: Institute of Diagnostic, Pediatric and Interventional Radiology, University Hospital of Bern, Inselspital, Freiburgstrasse 10, Bern, Switzerland.

ABSTRACT
Diffusion-weighted magnetic resonance imaging (DW-MRI) appears to hold promise as a non-invasive imaging modality in the detection of early microstructural and functional changes of different organs. DW-MRI is an imaging technique with a high sensitivity for the detection of a large variety of diseases in the urogenital tract. In kidneys, DW-MRI has shown promise for the characterization of solid lesions. Also in focal T1 hyperintense lesions DW-MRI was able to differentiate hemorrhagic cysts from tumours according to the lower apparent diffusion coefficient (ADC) values reported for renal cell carcinomas. Promising results were also published for the detection of prostate cancer. DW-MRI applied in addition to conventional T2-weighted imaging has been found to improve tumour detection. On a 3 T magnetic resonance unit ADC values were reported to be lower for tumours compared with the normal-appearing peripheral zone. The combined approach of T2-weighted imaging and DW-MRI also showed promising results for the detection of recurrent tumour in patients after radiation therapy. DW-MRI may improve the performance of conventional T2-weighted and contrast-enhanced MRI in the preoperative work-up of bladder cancer, as it may help in distinguishing superficial from muscle invasive bladder cancer, which is critical for patient management. Another challenging application of DW-MRI in the urogenital tract is the detection of pelvic lymph node metastases. As the ADC is generally reduced in malignant tumours and increased under inflammatory conditions, reduced ADC values were expected in patients with lymph node metastases.

Show MeSH
Related in: MedlinePlus