How to do and evaluate DWI and DCE-MRI sequences for diabetic foot assessment.

MRI evaluation of the diabetic foot is still a challenge not only from an interpretative but also from a technical point of view. The incorporation of advanced sequences such as diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) MRI into standard protocols for diabetic foot assessment could aid radiologists in differentiating between neuropathic osteoarthropathy (Charcot's foot) and osteomyelitis. This distinction is crucial as both conditions can coexist in diabetic patients, and they require markedly different clinical management and have distinct prognoses. Over the past decade, several studies have explored the effectiveness of DWI and dynamic contrast-enhanced MRI (DCE-MRI) in distinguishing between septic and reactive bone marrow, as well as soft tissue involvement in diabetic patients, yielding promising results. DWI, without the need for exogenous contrast, can provide insights into the cellularity of bone marrow and soft tissues. DCE-MRI allows for a more precise evaluation of soft tissue and bone marrow perfusion compared to conventional post-gadolinium imaging. The data obtained from these sequences will complement the traditional MRI approach in assessing the diabetic foot. The objective of this review is to familiarize readers with the fundamental concepts of DWI and DCE-MRI, including technical adjustments and practical tips for image interpretation in diabetic foot cases.

Usefulness of balanced SSFP sequence in robot-assisted MRI-guided prostate biopsy: Beyond scouting.

OBJECTIVES: To determine whether bSSFP images are useful for visualizing prostatic lesionsin MRI-guided in-bore transrectal biopsy. METHODS: This retrospective studyincluded 67 men witha single suspected cancer on MRI (PI-RADS 2.1 category ≥ 3) who underwent in-bore transrectal MRI-guided biopsy. Two uroradiologists independently rated lesion conspicuity on a 3-point scale (1:non-visible, 2:slightly visible, 3:clearly visible) on T2WI, DWI, and balanced SSFP.We used measures of frequency to compare lesion conspicuity in 3 sequences. We used Cohen's kappa to assess inter-rater reliability. RESULTS: Lesions were rated (1) non-visible in 18 % (12/67) of T2WI, 5 % (3/67) of DWI, and 10 % (7/67) of balanced SSFP images, (2) slightly visible in 56 % (37/67) on T2WI, 13 % (9/67) on DWI, and 48 % (32/67) on bSSFP, and (3) clearly visible in 27 %(18/67) on T2WI, 82 % (55/67) on DWI, and 42 % (28/67) on bSSFP. Lesions classified as prostate cancer at histology were slightly-clearly visible in 85 % (41/48) on T2WI, 100 % (48/48) on DWI, and 94 % (45/48) on bSSFP. Lesions classified as PI-RADS ≥ 4 were visible in 87 % (47/54) of T2WI, 100 % (54/54) of DWI, and 93 % (50/54) of bSSFP. Gleason ≥ 3 + 4 lesions were visible in 85 % (37/43) of T2WI, 100 % (43/43) of DWI, and 95 % (41/43) of bSSFP. Inter-rater agreement was excellent for T2WI (k = 0.97) and bSSFP (k = 0.94), and good for DWI (k = 0.75). CONCLUSION: Balanced SSFP is useful for visualizing prostatic lesions. Replacing T2WI with balanced SSFP can reduce the duration of in-bore transrectal MRI-guided biopsy.

Usefulness of prebiopsy multifunctional and morphologic MRI combined with free-to-total prostate-specific antigen ratio in the detection of prostate cancer.

OBJECTIVE: The purpose of the study was to assess the predictive value for prostate cancer of MRI using morphologic (T2-weighted imaging [T2WI]) and functional (MR spectroscopy [MRS], diffusion-weighted imaging [DWI], and dynamic contrast-enhanced [DCE] MRI) sequences and the free-to-total prostate-specific antigen (PSA) ratio, alone and combined. MATERIALS AND METHODS: This retrospective study included 70 patients (PSA level, > 4 ng/mL; free-to-total PSA ratio, < 20%) who underwent endorectal 1.5-T MRI before biopsy. We graded the likelihood of cancer on a 5-point scale. Imaging data were compared with histologic results on biopsy or prostatectomy. Accuracies were estimated from the area under receiver operating characteristic using the hemiprostate as the unit of analysis. A p value less than 0.05 denoted statistical significance. RESULTS: The model combining all variables was more accurate than each variable alone (95.2% vs 73.5% for T2WI, 76.0% for MRS, 81.8% for DWI, 75.6% for DCE-MRI, and 78.8% for free-to-total PSA ratio). The complete model had accuracy similar to that of combining two imaging variables with free-to-total PSA ratio, especially free-to-total PSA ratio, T2WI, and DWI (94.0%); and free-to-total PSA ratio, DWI, and MRS (93.8%); with negative predictive values of 91.0% and 89.5%, respectively. The best models combining two imaging variables (MRS and DWI, 85.8%; T2WI and DWI, 84.8%) had accuracy that was similar to that of the combination of all imaging variables (87.3%) and higher than that of the best individual imaging variable (DWI, 81.8%), but lower than that of the complete model. CONCLUSION: The combination of at least one functional technique with free-to-total PSA ratio is more accurate than combining only imaging variables in cancer detection. The use of more than two imaging variables does not increase the detection rate. Functional MRI has the potential to help avoid a large number of negative biopsies.

Robotic-assisted transrectal MRI-guided biopsy. Technical feasibility and role in the current diagnosis of prostate cancer: an initial single-center experience.

OBJECTIVES: To evaluate the potential clinical and technical utility to manage in practice the use of a robotic MRI in-bore-targeted prostate biopsies in the current work-up of prostate cancer diagnosis. METHODS: Thirty patients with a single cancer suspicious lesion interpreted on MRI using PI-RADSv2.1 category ≥ 3 underwent in-bore robotic transrectal MRI remote-controlled-guided biopsy. It was analyzed the technical success, clinical details, biopsy findings in correlation with the MRI examination, complications and cancer detection rate (CDR). RESULTS: The overall CDR for any cancer was 73% (22/30). It was 86% (19/22) for significant tumors (Gleason score of more than 6 or maximum cancer core length greater than 3 mm for Gleason 6) and 77% (17/22) for tumors with Gleason > 6. CDR for biopsy-naïve patients was 89% (16/18) and 50% (6/12) for patients with prior negative transrectal ultrasound-guided biopsies. The CDR for PI-RADS > 3 was 92% (22/24). All the lesions (n = 30) were reachable with the robotic MRI device. A self-limited rectal hemorrhagic complication was reported. CONCLUSION: This initial data show that a robotic MRI-guided biopsy could be useful, efficient and feasible procedure in the new paradigm to diagnose significant prostate cancer in selected patients.

Peripheral zone prostate cancer in patients with elevated PSA levels and low free-to-total PSA ratio: detection with MR imaging and MR spectroscopy.

PURPOSE: To retrospectively assess the value of endorectal magnetic resonance (MR) imaging and MR spectroscopy combined with the free-to-total prostate-specific antigen (PSA) ratio for detecting prostate cancer in men with elevated PSA levels. MATERIALS AND METHODS: The institutional review board approved the study, and all patients provided informed written consent. Endorectal MR imaging and MR spectroscopy were performed in 54 patients with PSA levels greater than 3 ng/mL but less than 15 ng/mL and free-to-total PSA ratio of less than 20%, followed by sextant biopsy in the peripheral zone. For each patient, MR imaging and MR spectroscopic findings, PSA level, and free-to-total PSA ratio were analyzed and compared with biopsy results and/or histopathologic tumor maps with regard to a sextant-modified distribution. The likelihood of cancer in each sextant according to MR and MR spectroscopic findings was graded independently on a scale of 1 (benign) to 5 (malignant). Detection accuracy and a multivariate logistic regression analysis were used to determine the most accurate combination of imaging, and clinical tests were used to detect prostate cancer according to the area under the receiver operating characteristic curve (AUC). RESULTS: The model incorporating MR imaging, MR spectroscopy, and free-to-total PSA ratio (AUC = 97.5%) was significantly more accurate in predicting prostate cancer than models using MR imaging alone (AUC = 85.1%; P = .007), MR spectroscopy alone (AUC = 87.2%; P = .041), or MR imaging and free-to-total PSA ratio combined (AUC = 90.8%; P = .038). CONCLUSION: MR and MR spectroscopy combined with free-to-total PSA ratio improves the predictive value for prostate cancer detection.

Diffusion-weighted whole-body MR screening.

Diffusion-weighted sequence (DWI) of the entire body is a new promising technique feasible to evaluate multifocal disease. DWI has revealed great potential in the evaluation of patients with cancer or benign disease, as it supplies both quantitative and qualitative information of the whole body. The technical aspects of the diffusion-weighted whole body (DWWB) MR sequence are described with special emphasis on the processing and analysis of the imaging. DWWB MR sequence should be used combined with the other standard sequences such as FSE T1-weighted and STIR images. A complete whole-body MR imaging protocol including the DWI can be performed in less than 40 min. The possibilities, limitations and the preliminary clinical results of the whole-body MR imaging using a DWI of the entire body are reviewed.

Diagnostic imaging: magnetic resonance imaging, computed tomography, and ultrasound.

The temporomandibular joint (TMJ) is a synovial joint. The TMJ is a freely movable articulation between the condyle of the mandible and the squamous portion of the temporal bone at the base of the skull. The bilateral articulation of the mandible to the cranium implies that the left and right TMJs must act as a single unit. Physical examination alone is inaccurate in determining the status of the joint. The primary rationale for imaging the TMJ lies in the fact that mechanical internal derangement is treated differently from the multiple miscellaneous disorders. It is mandatory to have a correct knowledge of the joint anatomy and normal function that correlates with conventional and cross-sectional imaging studies. The TMJ is illustrated with an overview of imaging strategies and techniques, especially magnetic resonance imaging, computed tomography, and ultrasound.

[Multiparametric MRI. The role of MRI techniques in the diagnosis, staging and follow up of prostate cancer]. / Resonancia magnética multiparamétrica. Papel de las técnicas de RM en el diagnóstico, estadiage y seguimiento del cáncer de próstata.

The current diagnosis of prostate cancer based on PSA values and systematic biopsy has limitations in its efficacy of detection and staging. Technical advances on imaging over the last decade, mainly MRI, enable improvements in the strategy of prostate cancer management in diagnosis, staging, follow up and therapy monitoring. MRI enables the combination of morphological (T2 sequences) and, at the same time, functional information by means of the application of sequences such as spectroscopy (SMRI), diffusion and dynamic intravenous contrast (CMRI) in the same study, giving the multiparametric MRI (mpMRI). Currently, it is not necessary to apply all sequences to obtain an mpMR study of optimal efficacy, so that a time shorter than 30 minutes is enough to obtain the necessary information depending on the clinical indication. The main clinical indications of prostatic MRI are a) local, regional or distance staging; b) Detection or guide for diagnostic biopsy for clinical risk suspicion or negative result in previous biopsies; c) active surveillance; and d) therapeutic monitoring. Furthermore, one of the most relevant features of prostate cancer, and a challenge for the mpMRI techniques is to be able to differentiate aggressive and non-significant neoplasias (latent). This update tries to review the current role of mpMRI in the management of prostate cancer using in combination the anatomical (T2) and functional (SMRI, DMRI and CMRI) information. We also describe the European prostate mpMRI guidelines, PI-RADS (Prostate imaging reporting data System).

Hemangioma from head to toe: MR imaging with pathologic correlation.

Hemangioma is a common benign vascular neoplasm that closely resembles normal vessels and can be found in all organs of the human body. Vascular lesions can be classified as infantile hemangiomas or vascular malformations on the basis of their natural history, location, cellular turnover, and histologic characteristics. The magnetic resonance (MR) imaging features of vascular malformations of the central nervous system depend on the pathologic subtype. Soft-tissue vascular malformations can be categorized with combined MR imaging and MR angiography as either high- or low-flow. Osseous vascular malformations commonly demonstrate a high-signal-intensity trabecular pattern at both T1- and T2-weighted MR imaging. A group of more aggressive vascular neoplasms, including hemangioendothelioma, hemangiopericytoma, and glomus tumor, have a nonspecific appearance at MR imaging. In the liver and spleen, hemangiomas are typically hyperintense at T2-weighted MR imaging, with a centripetal filling pattern after administration of gadopentetate dimeglumine. Vascular lesions can involve several organs or systems in angiomatous syndromes. MR imaging allows characterization of a hemangioma with typical features, which vary depending on anatomic location. Familiarity with these features facilitates diagnosis and management of these anomalies.

MR and MR angiography characterization of soft tissue vascular malformations.

Hemangioma is an abnormal proliferation of blood vessels that may occur in any vascularized tissue. Different classifications separate vascular lesions of soft tissues into hemangiomas and vascular malformations on the basis of their natural history, location, cellular turnover, and histology. Soft-tissue vascular malformations are relatively common. These lesions can be categorized on MR imaging because of their typical appearance as multiple lobules with fat overgrowth and serpentine channels, depending on the vascular flow. The combination of conventional MR and MR angiography (MRA) enable the differentiation between low-flow and high-flow vascular malformations and allows a noninvasive diagnostic strategy. This article reviews the MR and MRA imaging characteristics of soft-tissue hemangiomas to provide a helpful guide for radiologists to perform a more specific diagnosis and better management of these anomalies.