Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Benign Causes of Diffusion Restriction Foci in the Peripheral Zone
Transcript
Benign Causes of Diffusion Restric3on Foci in the Peripheral Zone of the Prostate: Diagnosis and Differen3al Diagnosis Nirjhor M. Bhowmik, MD; Jinxing Yu, MD; Ann S. Fulcher, MD; Mary A. Turner, MD Virginia Commonwealth University Richmond, Virginia Disclosure Statement The authors have no actual or poten3al conflicts of interest in rela3on to this presenta3on. Goals and Objec3ves • Discuss key mul3parametric MRI (Mp-‐MRI) features of benign causes of diffusion restric3on foci in the peripheral zone (PZ) of the prostate • Describe the clues that help dis3nguish benign causes of diffusion restric3on foci from prostate carcinoma (PCa) • Present pathologically proven examples Introduc3on • Prostate cancer is the most frequently diagnosed form of noncutaneous cancer in men • American Cancer Society es3mates about 220,800 new cases of prostate cancer for 2015 • Second leading cause of cancer death in men (27,540 deaths es3mated for 2015) • Approximately 1 in 6 men will be diagnosed with prostate cancer during their life3me Introduc3on • Current clinical screening methods such as PSA tes3ng or TRUS guided prostate biopsies for PCa lack sensi3vity and specificity • Mul3parametric MRI has emerged as an important tool in the diagnosis of PCa • Many benign en33es can demonstrate diffusion restric3on in the PZ that mimic PCa and create diagnos3c challenges Introduc3on • Examples of benign diffusion restric3on foci in the PZ include Ø Prosta33s Ø Hypertrophic nodule Ø Normal displaced central zone Ø Pseudolesion at the midline of the peripheral zone Ø Hemorrhage Ø Thickened surgical capsule Ø Prominent periprosta3c fat Ø Enlarged neurovascular bundle • In this poster, we will discuss MR findings of benign diffusion restric3on foci in the PZ of the prostate • The poster will focus on the clues that help differen3ate these mimics from prostate cancer • The target audience for this poster is radiologists Outline I. Key MRI Features of Prostate Cancer at the PZ II. Key MRI Features of Benign Causes of Diffusion Restric3on Foci in the PZ Ø Chronic Prosta33s Ø Hypertrophic Nodule Ø Normal Displaced Central Zone Ø Pseudolesion at the Midline of the Peripheral Zone Ø Hemorrhage Ø Thickened Surgical Capsule Ø Prominent Periprosta3c Fat Ø Enlarged Neurovascular Bundle III. Summary and Clinical Implica3ons Key MRI Features of PCa at the PZ • T2WI: PCa shows a round or ill-‐defined low signal intensity focus (Fig. 1A and 2A). • Diffusion Weighted Imaging (DWI) – ADC Map: PCa has a lower ADC value (dark) than normal prostate 3ssue. A lesion with very low ADC value at the PZ is strongly sugges3ve of PCa (Fig. 1B and 2B). ADC values correlate well with PCa Gleason scores. • Dynamic Contrast Enhanced MRI (DCE): PCa shows an area with rapid contrast wash in and wash out. Typically, PCa is a focus with the earliest and strongest enhancement in the prostate (Fig. 1C and 2C). Prostate Cancer at the Peripheral Zone T2 ADC DCE A B C Figure 1 – PCa Gleason score 7 at the leg mid peripheral zone. A) Axial T2 shows a large low signal lesion with mass effect at the leg mid PZ (arrow). There is evidence of extracapsular tumor extension (curved arrow). B) ADC map shows low ADC value of the lesion (arrow). C) DCE demonstrates rapid contrast wash in and wash out of the lesion (arrow). Prostate Cancer at the Peripheral Zone T2 ADC DCE A B C Figure 2 – PCa Gleason score 9 at the leg mid PZ. A) Axial T2 shows a large low signal lesion with mass effect at the leg mid PZ (arrow). B) ADC map shows low ADC value of the lesion (arrow). There is evidence of extracapsular tumor extension (curved arrow). C) DCE demonstrates rapid contrast wash in and out of the lesion (arrow). Chronic Prosta33s • Chronic prosta33s is a very common cause of elevated PSA levels • Features that mimic prostate cancer: – Focal low T2 signal area in the PZ – Rapid contrast wash in and out on DCE – Diffusion restric3on • Key clues for differen3a3on include: – No contour deformity adjacent to low T2 signal region (geographic appearance) (Fig. 3A) – Ill-‐defined or linear margins on T2WI – DWI-‐ADC map more mild compared with PCa (Fig. 3B) – DCE may show bilateral symmetric enhancement (Fig. 3C) Chronic Prosta33s T2 A ADC B DCE C Figure 3 – Prosta33s in a pa3ent with PSA of 3.7. A) Axial T2WI shows low T2 signal intensity in the leg mid PZ without contour deformity (arrow). B) ADC map demonstrates mild diffusion restric3on in the PZ (arrow). C) DCE shows bilateral symmetric enhancement (arrows). Targeted biopsy confirmed chronic inflamma3on and not a tumor. Hypertrophic Nodule in the PZ • Hypertrophic nodules may appear in the PZ, commonly arising from the central gland • Features that mimic prostate cancer: – Low T2 signal intensity (Fig. 4A and 4B) – Low ADC value (Fig. 4C) – Rapid contrast wash in and out • Key clues for differen3a3on include: – Nodules are generally rounded or spherical in shape with a very sharp contour and are more well defined than PCa (Fig. 4A) – There is usually a layer of normal prostate 3ssue between the nodule and prostate capsule (Fig. 4A). In contrast, PCa ogen extends to the capsule (Fig. 1A and 2B) Hypertrophic Nodule in PZ Axial T2 A Sag T2 B ADC C Figure 4 – Hypertrophic nodule at the leg mid PZ mimicking PCa. A) Axial T2WI shows a well defined low signal lesion at the leg mid PZ (arrow). The arrowhead indicates a layer of normal prostate 3ssue between the lesion and capsule. B) Sagikal T2WI shows the well defined lesion (arrow). C) ADC map shows low ADC value of the lesion (arrow). Biopsies confirmed no prostate cancer. Normal Displaced Central Zone • When the transi3onal zone is enlarged, the central zone may be displaced to the base of the prostate • Features that mimic prostate cancer: – Homogeneous low T2 signal intensity (Fig 5A) – May have low ADC value (Fig. 5C) • Key clues for differen3a3on include: – The displaced central zone is well defined – May be symmetric bilaterally on all sequences with classic loca3on at the level of the ejaculatory ducts – The central zone does not enhance rapidly (Fig. 5D) Normal Displaced Central Zone T2 Axial T2 Sagikal A ADC DCE SV B C D Figure 5 -‐ Displaced central zone at the leg base PZ mimicking PCa. The pa3ent had elevated PSA to 12 and had 3 nega3ve TRUS guided prostate biopsies. A) and B) T2WI show a well defined low signal area at the leg base PZ (arrow) just inferior to the seminal vesicle (SV). C) ADC map shows decreased ADC value of the area (arrow). D) DCE shows no significant contrast enhancement of the area (arrow). MRI guided biopsy confirmed normal prostate 3ssue. Pseudolesion at the Midline of the PZ • At the midline of the PZ, it is common to have a low T2 signal focus • It is believed that fusion of the prosta3c capsule and fascia at this region is responsible for the low T2 signal focus • Features that mimic prostate cancer: – Low T2 signal focus (Fig. 6A) – May show diffusion restric3on (Fig. 6B) • Key clues for differen3a3on include: – The low T2 signal focus is at the midline – The contour of the prostate at the focus is concave – No dynamic contrast enhancement (Fig. 6C) Pseudolesion at the Midline of the PZ T2 A ADC B DCE C Figure 6 – Pseudolesion at the midline of the PZ. The pa3ent had elevated PSA to 8 and had mul3ple nega3ve TRUS biopsies. A) Axial T2 shows a low T2 signal intensity region at the midline of the PZ (arrow). B) ADC map shows low ADC value of the region (arrow). C) DCE demonstrates no enhancement (arrow). MRI guided biopsy confirmed no cancer. Hemorrhage • Prostate hemorrhage following TRUS guided prostate biopsy is common • 8 weeks delay is recommended for a prostate MRI study following biopsy • Features that mimic prostate cancer: – Low T2 signal intensity (Fig. 7A) – May show diffusion restric3on (Fig. 7B) – May show abnormal enhancement • Key clues for differen3a3on include: – Mild signal intensity on ADC map compared to PCa – Milder changes on DCE compared to PCa – High T1 signal intensity (Fig. 7C) Hemorrhage T2 A ADC T1 B C Figure 7 – Hemorrhage at the leg apex of the PZ. The pa3ent had elevated PSA to 12.5 and had mul3ple nega3ve TRUS biopsies. A) Axial T2 shows a low T2 signal intensity region in the leg apex of the PZ (arrow). B) ADC map shows mild low ADC value of the region (arrow). C) Axial T1 shows high signal intensity focus in the same region (arrow). Thickened Surgical Capsule • Prolifera3on and thickening of the fibromuscular layer between the transi3onal and peripheral zone, ogen from outward pressure from the development of BPH • Features that mimic prostate cancer: – Low T2 signal intensity – Decreased ADC (Fig. 8B) • Key clues for differen3a3on include: – Band-‐like or crescen3c shape (Fig. 8A) – No dynamic contrast enhancement (Fig. 8C) – Located at the junc3on of the PZ and central gland Thickened Surgical Capsule T2 A ADC DCE B C Figure 8 – Thickened leg surgical capsule. The pa3ent had elevated PSA to 12.5 and had prior nega3ve TRUS biopsies. A) Axial T2 shows low T2 signal of a thickened band-‐like layer between the leg transi3onal and peripheral zone (arrow). B) ADC map shows low ADC value of the corresponding region (arrow). C) DCE shows no enhancement of the region (arrow). Prominent Periprosta3c Fat • Prominent periprosta3c fat is very common along the prostate capsule • Features that mimic prostate cancer: – May show significant diffusion restric3on (Fig. 9B) • Key clues for differen3a3on include: – High T2 signal intensity (Fig. 9A) – Adjacent to but outside the prostate – No dynamic contrast enhancement Prominent Periprosta3c Fat T2 A ADC B Figure 9 – Prominent periprosta3c fat. The pa3ent had a PSA of 8.7 and prior nega3ve TRUS biopsies. A) Axial T2 shows high T2 signal focus near the leg apex of the peripheral zone (arrow). B) ADC map shows low ADC value of the corresponding focus (arrow). Enlarged Neurovascular Bundle • Neurovascular bundle (NVB) includes the nervous plexus, arteries, veins, and addi3onal smaller nerve branches • Proximity of the NVB to the peripheral zone can create a challenge in assessing for focal peripheral zone lesions • Features that mimic prostate cancer: – Decreased T2 signal intensity (Fig. 10A & B) – Decreased signal on ADC map (Fig. 10C) • Key clues for differen3a3on include: – Typical loca3on along the lateral margin of the PZ – Discrete rounded appearance on an axial slice and more tubular morphology when tracked across mul3ple slices – May have delayed venous enhancement due to small venous structures Enlarged Neurovascular Bundle Axial T2 A Coronal T2 ADC B C Figure 10 – Enlarged neurovascular bundle. The pa3ent had a PSA of 8.7 and prior nega3ve TRUS biopsies. A) Axial T2 shows low T2 signal foci along the right base lateral aspect PZ (arrow). B) Coronal T2 shows tubular structures with low T2 signal intensity along the right lateral aspect (arrow). C) ADC map shows low ADC value of the corresponding foci along the right base PZ (arrow). Summary of Key Clues in Differen3a3on from PCa Benign Causes of Diffusion Restric3on Foci in the PZ Key Clues in Differen3a3on Chronic Prosta33s • • • Ill-‐defined margins with no contour deformity Slight diffusion restric3on Mild, usually symmetric, contrast wash-‐in and wash-‐out Hypertrophic Nodule in the PZ • • Round shape with well-‐defined margins Layer of normal 3ssue between nodule and prostate capsule Normal Displaced Central Zone • • Commonly symmetric and at the level of ejaculatory ducts No or minimal rapid contrast wash-‐in and wash-‐out Pseudolesion at the Midline of the PZ • • Midline loca3on with concave contour of the prostate at the focus No rapid contrast wash-‐in or wash-‐out Hemorrhage • • Mild diffusion restric3on High T1 signal intensity Thickened Surgical Capsule • • Band-‐like or crescen3c shape at the junc3on of the PZ and central gland No rapid contrast wash-‐in or wash-‐out Prominent Periprosta3c Fat • • • High T2 signal intensity Adjacent to but outside the prostate No rapid contrast wash-‐in or wash-‐out Enlarged Neurovascular Bundle • • Tubular appearance on at least one plane Located along lateral margins of the PZ Summary and Clinical Implica3ons • A wide variety of benign en33es at the PZ can have diffusion restric3on on Mp-‐MRI and mimic prostate cancer • Knowledge of the key MR features of these mimics will help dis3nguish them from prostate cancer • A correct diagnosis is important to help guide clinical management and avoid unnecessary interven3on References • • • • • • • • • • • • Bonekamp D, Jacobs M, et al. Advancements in MR imaging of the prostate: from diagnosis to interven3ons. Radiographics 2011; 31:677-‐703 Rosenkrantz AB, Taneja, SS. Radiologist, be aware: ten pimalls that confound the interpreta3on of mul3parametric prostate MRI. AJR 2014; 202: 109-‐120. Yu J, Fulcher AS, et al. Prostate cancer and its mimics at mul3parametric prostate MRI. Br J Radiol 2014; 87:20130659 Shukla-‐Dave A, Hricak H, Eberhardt SC, et al. Chronic prosta33s: MR imaging and 1H MR spectroscopic imaging findings —ini3al observa3ons. Radiology 2004; 231:717–724 Rosenkrantz AB, Kopec M, Kong X, et al. Prostate cancer vs. post-‐biopsy hemorrhage: diagnosis with T2-‐ and diffusion-‐ weighted imaging. J Magn Reson Imaging 2010; 31:1387–1394 What are the key sta3s3cs about prostate cancer? (2015, January 5). Retrieved January 7, 2015, from hkp:// www.cancer.org/acs/groups/cid/documents/webcontent/003134-‐pdf.pdf Kubota Y, Kamei S, Nakano M, et al. The poten3al role of prebiopsy magne3c resonance imaging combined with prostate-‐specific an3gen density in the detec3on of prostate cancer. Int J Urol 2008; 15:322–326 Langer DL, van der Kwast TH, Evans AJ, et al. Prostate cancer detec3on with mul3-‐parametric MRI: logis3c regression analysis of quan3ta3ve T2, diffusion-‐weighted imaging, and dynamic contrast-‐enhanced MRI. J Magn Reson Imaging 2009; 30:327–334 Haider MA, van der Kwast TH, Tanguay J, et al. Combined T2-‐weighted and diffusion-‐weighted MRI for localiza3on of prostate cancer. AJR 2007; 189:323–328 Tanimoto A, Nakashima J, Kohno H, et al. Prostate cancer screening: the clinical value of diffusion-‐weighted imaging and dynamic MR imaging in combina3on with T2-‐weighted imaging. J Magn Reson Imaging 2007; 25:146–152 Kitajima K, Kaji Y, Fukabori Y, et al. Prostate cancer detec3on with 3 T MRI: comparison of diffusion-‐weighted imaging and dynamic contrast-‐enhanced MRI in combina3on with T2-‐weighted imaging. J Magn Reson Imaging 2010; 31:625– 631 Fukerer JJ, Heijmink SW, Scheenen TW, et al. Prostate cancer: local staging at 3-‐T endorectal MR imaging—early experience. Radiology 2006; 238:184–191 Author Contact Informa3on: Dr. Nirjhor Bhowmik, MD (nbhowmik@mcvh-‐vcu.edu)
