A semi-automated software program to assess the impact of second reads in prostate MRI for equivocal lesions: results from a UK tertiary referral centre.

PURPOSE: To investigate the utility of a prostate magnetic resonance imaging (MRI) second read using a semi-automated software program in the one-stop clinic, where patients undergo multiparametric MRI, review and biopsy planning in one visit. We looked at concordance between readers for patients with equivocal scans and the possibility for biopsy deferral in this group. METHODS: We present data from 664 consecutive patients. Scans were reported by seven different expert genitourinary radiologists using dedicated software (MIM®) and a Likert scale. All scans were rescored by another expert genitourinary radiologist using a customised workflow for second reads that includes annotated biopsy contours for accurate visual targeting. The number of scans in which a biopsy could have been deferred using biopsy results and prostate specific antigen density was assessed. Gleason score ≥ 3 + 4 was considered clinically significant disease. Concordance between first and second reads for equivocal scans (Likert 3) was evaluated. RESULTS: A total of 209/664 (31%) patients scored Likert 3 on first read, 128 of which (61%) were concordant after second read. 103/209 (49%) of patients with Likert 3 scans were biopsied, with clinically significant disease in 31 (30%) cases. Considering Likert 3 scans that were both downgraded and biopsied using the workflow-generated biopsy contours, 25/103 (24%) biopsies could have been deferred. CONCLUSIONS: Implementing a semi-automated workflow for accurate lesion contouring and targeting biopsies is helpful during the one-stop clinic. We observed a reduction of indeterminate scans after second reading and almost a quarter of biopsies could have been deferred, reducing the potential biopsy-related side effects.

Quantified Terminal Ileal Motility during MR Enterography as a Biomarker of Crohn Disease Activity: Prospective Multi-Institution Study.

Purpose To evaluate the accuracy of MRI-quantified small bowel motility for Crohn disease activity against endoscopic and histopathologic reference standards. Materials and Methods For this prospective study, 82 participants (median age, 31 years; range, 16 to 70 years; 42 males [median age, 31 years; range, 17 to 70 years] and 40 females [median age, 31 years; range, 16 to 63 years) underwent colonoscopy and MR enterography within 14 days (from October 2011 to March 2014) at two centers. The Crohn disease endoscopic index of severity (CDEIS), histopathologic activity score (endoscopic biopsy acute histologic inflammatory score [EAIS]), and MR index of activity (MaRIA) were scored in the terminal ileum. Terminal ileal motility was quantified by using an image registration based-motility assessment algorithm (hereafter, Motility). Sensitivity and specificity of Motility (˂0.3 arbitrary units) and MaRIA (≥7 and ≥11) for disease activity (CDEIS ≥4 or EAIS ≥1) were compared by using the McNemar test. Receiver operating characteristic curves were constructed and areas under the curve were compared. Motility was correlated with reference standards by using Spearman rank estimates. Results Terminal ileal Motility was negatively correlated with EAIS (r =-0.61; 95% confidence interval [CI]: 0.7, -0.5) and CDEIS (r = -0.59; 95% CI: 0.7, -0.4). With CDEIS as the standard of reference, Motility had higher sensitivity than did MaRIA (≥11) (93% vs 78%, respectively; P = .03), but lower specificity (61% vs 81%, respectively; P = .04). With EAIS as the standard of reference, Motility had higher sensitivity than did MaRIA (≥7) (92% vs 75%, respectively; P = .03) but similar specificity (71% vs 74%, respectively; P >.99). The area under the receiver operating characteristic curve for Motility was 0.86 and 0.87 with CDEIS and EAIS as the standard of reference, respectively. Conclusion The terminal ileal Motility score showed good agreement with endoscopic and histopathologic activity in Crohn disease. © RSNA, 2018 Online supplemental material is available for this article.

Evaluation of Crohn's disease activity: initial validation of a magnetic resonance enterography global score (MEGS) against faecal calprotectin.

OBJECTIVES: To develop an MRI enterography global score (MEGS) of Crohn's disease (CD) activity compared with a reference standard of faecal calprotectin (fC), C-reactive protein (CRP) and Harvey-Bradshaw index (HBI). METHODS: Calprotectin, CRP and HBI were prospectively recorded for 71 patients (median age 33, male 35) with known/suspected CD undergoing MRI enterography. Two observers in consensus scored activity for nine bowel segments, grading mural thickness, T2 signal, mesenteric oedema, T1 enhancement and pattern, and haustral loss. Segmental scores were multiplied according to disease length. Five points each were added for lymphadenopathy, comb sign, fistulae and abscesses to derive the MEGS. A previously validated MRI CD activity score (CDAS) was also calculated. MRI scores were correlated with clinical references using Spearman's rank. A logistic regression diagnostic model was built to discriminate active (fC > 100 µg/g) from inactive disease. RESULTS: MEGS and CDAS were significantly correlated with fC (r = 0.46, P < 0.001) and (r = 0.39, P = 0.001) respectively. MEGS correlated with CRP (r = 0.39, P = 0.002). The model for discriminating active from inactive disease achieved an area under the receiver-operating curve of 0.75 and 0.66 after leave-one-out analysis. CONCLUSION: A magnetic resonance enterography global score (MEGS) of CD activity correlated significantly with fC levels. KEY POINTS: • Magnetic resonance imaging is now widely used to assess Crohn's disease. • Existing MRI activity scores depend on local segmental endoscopic/histological reference standards. • Scores including assessment of disease extent/complications better demonstrate full disease burden. • This new global Crohn's disease burden score correlates with calprotectin and CRP. • The MRI enterography score of disease activity can complement existing clinical markers.

Grading Crohn disease activity with MRI: interobserver variability of MRI features, MRI scoring of severity, and correlation with Crohn disease endoscopic index of severity.

OBJECTIVE: The purpose of this article is to assess the interobserver variability for scoring MRI features of Crohn disease activity and to correlate two MRI scoring systems to the Crohn disease endoscopic index of severity (CDEIS). MATERIALS AND METHODS: Thirty-three consecutive patients with Crohn disease undergoing 3-T MRI examinations (T1-weighted with IV contrast medium administration and T2-weighted sequences) and ileocolonoscopy within 1 month were independently evaluated by four readers. Seventeen MRI features were recorded in 143 bowel segments and were used to calculate the MR index of activity and the Crohn disease MRI index (CDMI) score. Multirater analysis was performed for all features and scoring systems using intraclass correlation coefficient (icc) and kappa statistic. Scoring systems were compared with ileocolonoscopy with CDEIS using Spearman rank correlation. RESULTS: Thirty patients (median age, 32 years; 21 women and nine men) were included. MRI features showed fair-to-good interobserver variability (intraclass correlation coefficient or kappa varied from 0.30 to 0.69). Wall thickness in millimeters, presence of edema, enhancement pattern, and length of the disease in each segment showed a good interobserver variability between all readers (icc = 0.69, κ = 0.66, κ = 0.62, and κ = 0.62, respectively). The MR index of activity and CDMI scores showed good reproducibility (icc = 0.74 and icc = 0.78, respectively) and moderate CDEIS correlation (r = 0.51 and r = 0.59, respectively). CONCLUSION: The reproducibility of individual MRI features overall is fair to good, with good reproducibility for the most commonly used features. When combined into the MR index of activity and CDMI score, overall reproducibility is good. Both scores show moderate agreement with CDEIS.

Derivation of a T2-weighted MRI total colonic inflammation score (TCIS) for assessment of patients with severe acute inflammatory colitis-a preliminary study.

OBJECTIVE: To derive an MRI score for assessing severity, therapeutic response and prognosis in acute severe inflammatory colitis. METHODS: Twenty-one patients with acute severe colitis underwent colonic MRI after admission and again (n = 16) after median 5 days of treatment. Using T2-weighted images, two radiologists in consensus graded segmental haustral loss, mesenteric and mural oedema, mural thickness, and small bowel and colonic dilatation producing a total colonic inflammatory score (TCIS, range 6-95). Pre- and post-treatment TCIS were compared, and correlated with CRP, stool frequency, and number of inpatient days (therapeutic response marker). Questionnaire assessment of patient worry, satisfaction and discomfort graded 1 (bad) to 7 (good) was administered RESULTS: Admission TCIS correlated significantly with CRP (Kendall's tau=0.45, 95% confidence interval [CI] 0.11-0.79, p = 0.006), and stool frequency (Kendall's tau 0.39, 95% CI 0.14-0.64, p = 0.02). TCIS fell after treatment (median [22 range 15-31]) to median 20 [range 8-25], p = 0.01. Admission TCIS but not CRP or stool frequency was correlated with length of inpatient stay (Kendall's tau 0.40, 95% CI 0.11-0.69, p = 0.02). Patients reported some discomfort (median score 4) during MRI. CONCLUSIONS: MRI TCIS falls after therapy, correlates with existing markers of disease severity, and in comparison may better predict therapeutic response.

Photodynamic therapy for prostate cancer--a review of current status and future promise.

Debate is ongoing about the treatment of organ-confined prostate cancer, particularly in men who have low-risk disease detected by PSA screening. A balance is needed between the harms and benefits of treatment. New techniques are being developed that aim to offer similar treatment effects to current radical therapies, while reducing the associated harmful effects of these treatments. In this Review, we explore the potential of one such technique, photodynamic therapy (PDT), for the treatment of organ-confined prostate cancer. PDT uses a photosensitizing drug that is activated in the prostate by low-power laser light, delivered using optical fibers. The fibers are placed within needles in the prostate, guided by transrectal ultrasound and a perineal template. Following the activation of the photosensitizer by light, and the formation of reactive oxygen species, necrosis occurs at the site of interaction between the photosensitizer, light and oxygen. Clinical studies are underway to investigate the use of PDT for primary and salvage treatment of organ-confined prostate cancer. We review these studies, the potential strategies for enhanced photodynamic effects, and the current limitations of PDT for prostate cancer.

MR to ultrasound image registration for guiding prostate biopsy and interventions.

A method is described for registering preoperative magnetic resonance (MR) to intraoperative transrectal ultrasound (TRUS) images of the prostate gland. A statistical motion model (SMM) of the prostate is first built using training data provided by biomechanical simulations of the motion of a patient-specific finite element model, derived from a preoperative MR image. The SMM is then registered to a 3D TRUS image by maximising the likelihood of the shape of an SMM instance given a voxel-intensity-based feature, which represents an estimate of normal vector at the surface of the prostate gland. Using data acquired from 7 patients, the accuracy of registering T2 MR to 3D TRUS images was evaluated using anatomical landmarks inside the gland. The results show that the proposed registration method has a root-mean-square target registration error of 2.66 mm.

A statistical motion model based on biomechanical simulations for data fusion during image-guided prostate interventions.

A method is described for generating a patient-specific, statistical motion model (SMM) of the prostate gland. Finite element analysis (FEA) is used to simulate the motion of the gland using an ultrasound-based 3D FE model over a range of plausible boundary conditions and soft-tissue properties. By applying principal component analysis to the displacements of the FE mesh node points inside the gland, the simulated deformations are then used as training data to construct the SMM. The SMM is used to both predict the displacement field over the whole gland and constrain a deformable surface registration algorithm, given only a small number of target points on the surface of the deformed gland. Using 3D transrectal ultrasound images of the prostates of five patients, acquired before and after imposing a physical deformation, to evaluate the accuracy of predicted landmark displacements, the mean target registration error was found to be less than 1.9 mm.

Will focal therapy become a standard of care for men with localized prostate cancer?

The current treatment choice for men with localized prostate cancer lies between active surveillance and radical therapy. The difference between these two extremes of care is 5% in terms of cancer-related absolute mortality at 8 years. It is generally accepted that this small difference will decrease for men diagnosed in the prostate-specific-antigen era. Radical therapy is associated with considerable adverse effects (e.g. incontinence, impotence, rectal problems) because it treats the whole gland, and damages surrounding structures in up to half of men. Men are being diagnosed at a younger age with lower-risk disease, and many have unifocal or unilateral disease. We propose a new concept whereby only the tumor focus and a margin of normal tissue are treated. This paradigm might decrease adverse effects whilst, at the same time, retaining effective cancer control. The arguments for and against active surveillance and radical therapy are reviewed in this article, with focal therapy presented as a means for bridging these two approaches.