MRI Identification Research Articles

PP05 Presentation Time: 9:56 AM: The Performance of Multiparametric MRI in Identification of Intraprostatic Tumor Deposits After Local Prostate Radiation Therapy

PP05 Presentation Time: 9:56 AM: The Performance of Multiparametric MRI in Identification of Intraprostatic Tumor Deposits After Local Prostate Radiation Therapy

The Accuracy of Multiparametric MRI in Identification of Intraprostatic Tumor Deposits after Local Prostate Radiation Therapy

<h3>Purpose/Objective(s)</h3> To determine the accuracy of multiparametric (mp) MRI in identification of intraprostatic tumor deposits in prostate cancer patients previously treated with local radiation therapy (RT) using a systematic and targeted MR-guided transperineal prostate biopsy technique as a reference to guide and improve clinical workflow processes. <h3>Materials/Methods</h3> Twenty-three patients with localized prostate cancer who had been previously treated with external beam RT, brachytherapy, or combined external beam RT and brachytherapy, underwent a combined systematic and targeted MRI-guided prostate biopsy using a transperineal approach under general anesthesia. For each patient, a pre-biopsy mpMRI scan was obtained and imported into a prostate biopsy planning system. Transverse T2-weighted images were then reoriented from the supine to dorsal lithotomy position. Dividing the prostate into an apical and base section, a systematic array of transperineal biopsies spaced approximately 10mm apart was planned with additional biopsies targeting any mpMRI-identified PI-RADS 3, 4, or 5 lesions. Biopsy procedures were carried out in the dorsal lithotomy position using a transrectal ultrasound with stepper-stabilizer and template grid. Matching of the planning mpMRI images to live ultrasound images was achieved using the template grid as a reference. <h3>Results</h3> All patients successfully underwent their biopsy procedure as planned. The median PSA prior to biopsy was 5.5 ng/mL (range 2.1-24.6). The median number of biopsy specimens obtained per patient was 21 (range 13-34). Overall, the positive predictive value (PPV) of any PI-RADS 3-5 lesion (based on pathologic confirmation) was 81% (21/26). The individual PPV of PI-RADS 3, 4 and 5 lesions were 25% (1/4), 89% (16/18), and 100% (4/4), respectively. Forty-eight percent (11/23) of patients harbored mpMRI-unidentified prostate cancer. Thirty-five percent (8/23) of patients harbored mpMRI-unidentified GS≥7 disease. <h3>Conclusion</h3> Using prostate mpMRI to identify intraprostatic tumor deposits after local radiation therapy results in a high PPV, particularly for PI-RADS 4 and 5 lesions. However, given the high rate of mpMRI-unidentified prostate cancer, the addition of systematic transperineal prostate biopsy information appears necessary to improve the accuracy of mpMRI identification of intraprostatic tumor deposits.

MP51-13 FLUORINE-18 (18F) PROSTATE-SPECIFIC MEMBRANE ANTIGEN (PSMA) POSITRON EMISSION TOMOGRAPHY (PET) AND THE DIAGNOSIS AND STAGING OF PRIMARY PROSTATE CANCER (PCA)

MP51-13 FLUORINE-18 (18F) PROSTATE-SPECIFIC MEMBRANE ANTIGEN (PSMA) POSITRON EMISSION TOMOGRAPHY (PET) AND THE DIAGNOSIS AND STAGING OF PRIMARY PROSTATE CANCER (PCA)

Magnetic resonance imaging in diagnosis of complications of kidney and ureteral injury in different periods of traumatic disease

To assess the possibility of magnetic resonance imaging in diagnosis of complications of kidney and ureteral injury in different periods of traumatic disease. There were 139 patients with kidney and ureteral injuries between 2015 and 2019. We clarified the MR-signs of renal complications in different periods of traumatic disease. We analyzed the effectiveness of MRI in identification of renal complications compared to ultrasound, excretory urography, computed tomography, intraoperative and follow-up data. High diagnostic accuracy of MRI for early and late manifestations of traumatic disease was demonstrated.

Accuracy of Prostate Multiparametric MRI in Identification of Intraprostatic Tumor Deposits Validated on Transperineal Biopsies

To determine the accuracy of prostate multiparametric (mp) MRI in identification of intraprostatic tumor deposits using a systematic and targeted MR-guided transperineal prostate biopsy technique as a reference.One hundred sixty patients underwent a combined systematic and targeted MRI-guided prostate biopsy using a transperineal approach under general anesthesia. For each patient, a pre-biopsy mpMRI scan was obtained and imported into a prostate biopsy planning system. Transverse images were then reoriented from the supine to dorsal lithotomy position. Dividing the prostate into an apical and base section, a systematic array of transperineal biopsies spaced approximately 10mm apart was planned with additional biopsies targeting mpMRI-identified PI-RADS 3, 4 or 5 lesions. Biopsy procedures were carried out in the dorsal lithotomy position using a transrectal ultrasound with stepper-stabilizer and template grid. Matching of the planning mpMRI images to live ultrasound images was achieved using the template grid as a reference.All patients successfully underwent their biopsy procedure as planned. An average of 26 biopsy specimens were obtained per patient (range 11-44). Twenty-nine percent (15/52) of PI-RADS 3 lesions, 49% (46/94) of PI-RADS 4 lesions, and 76% (39/51) of PI-RADS 5 lesions were pathologically confirmed prostate cancer. Forty-two percent (67/160) of patients harbored mpMRI-unidentified prostate cancer. Twenty-two percent (36/160) of patients harbored mpMRI-unidentified GS≥7 disease and four percent (7/160) of patients harbored mpMRI-unidentified GS≥8 disease.Using prostate mpMRI to identify intraprostatic tumor deposits without pathologic confirmation would lead to significant numbers of false positive mpMRI identified lesions and miss clinically significant prostate cancer outside of mpMRI identified lesions in over 20% of patients. Use of systematic prostate biopsy information appears necessary to significantly improve the accuracy of mpMRI identification of intraprostatic tumor deposits.

Role of MRI in identification, characterization and assessing the sequelae of lumbar disc degenerative changes

Role of MRI in identification, characterization and assessing the sequelae of lumbar disc degenerative changes

NIMG-08EVALUATION OF 2HG MR SPECTROSCOPY IN RELATION TO DISEASE ACTIVITY IN GLIOMAS

The oncometabolite 2-hydroxyglutarate (2HG) is produced by mutated isocitrate dehydrogenase (IDH). Magnetic resonance spectroscopy (MRS) detects 2HG noninvasively and has been reported to accurately identify IDH mutated tumors. 2HG-MRS may be able to help monitor disease activity over time, adding significantly to the diagnostic utility of conventional MRI. To evaluate implementation of 2HG spectroscopy and relationship to disease state, we performed 2HG-MRS on 21 patients with known glioma or MRI abnormalities suspicious for glioma (without prior biopsy) at our institution. When pathology was available, cases were assessed for diagnosis and tumor grade, IDH and 1p19q status as well as treatment history and clinical course. Analysis of 2HG-MRS results were done blinded to known IDH status. In 12 tumors with known IDH status, 9 cases were IDH-mutated, and 3 IDH-wildtype, and 5 were 1p19q-codeleted (and thus necessarily IDH-mutated). Out of all 21 patients, 8 were positive for 2HG by MRS and 13 were negative. In tumors with known IDH mutation, there was concordance with positive 2HG-MRS in 4 of 9. Due to this unexpected rate of apparent false negative 2HG-MRS, the 5 discordant cases were further reviewed. Three were clinically and radiographically stable by conventional MRI post treatment, so it is possible that absence of detectable 2HG reflected lack of active disease. However, 2 cases were negative for 2HG-MRS despite apparent progressive radiographic disease by conventional MRI. In contrast, all 4 concordant cases showed evidence of active or progressive tumor by conventional MRI. 2HG-MRS can aid conventional MRI in identification of IDH mutated gliomas non-invasively and may provide a more definitive assessment of treatment response for IDH mutated gliomas. However, it remains possible that some of our discordant cases represent insufficient sensitivity of 2HG-MRS, and further investigation is needed to optimize the sensitivity and specificity of 2HG-MRS for this purpose.

Cerebral Arteriovenous Malformations at 3.0 T

Prospective intraindividual comparison of 4-dimensional contrast-enhanced MR angiography (4D-MRA) in combination with selective arterial spin labeling (ASL) at 3.0 Tesla and digital subtraction angiography (DSA) for anatomic and functional characterization of cerebral arteriovenous malformations (AVMs). In a prospective intraindividual comparative study, 16 patients diagnosed with symptomatic cerebral AVMs underwent 4D-MRA at an isotropic spatial resolution of 1.1 x 1.1 x 1.1 mm and a temporal resolution of 572 milliseconds, regional brain perfusion imaging using selective ASL and DSA. Selective ASL was performed for selective labeling of both carotid arteries and the vertebrobasilar complex. In a stepwise approach, all images were evaluated by 2 radiologists according to technical success rate, Spetzler-Martin classification, identification of arterial feeders, and existence of anatomic variants or functional cross-filling. 4D-MRA allowed for the same Spetzler-Martin classification as DSA in all patients. Of 28, 26 (93%) feeding arteries were correctly identified by both readers using 4D-MRA alone. Selective ASL provided additional functional or anatomic information in 4 of 16 cases (25%), enabling the detection of a cross-filling feeding artery that was not identified by 4D-MRA without selective ASL, thus improving the sensitivity of MRI in identification of arterial feeders from 26/28 (93%) to 27/28 (96%). The additional functional information regarding anatomic variants and cross-filling provided by selective ASL was confirmed by DSA in all cases. 4D-MRA in combination with selective arterial spin labeling is a promising tool for the noninvasive assessment of cerebral AVMs providing functional information that so far has been gained only with DSA.

MRI Assessment of Recurrent Carpal Tunnel Syndrome After Open Surgical Release of the Median Nerve

The purpose of this study was to retrospectively determine the accuracy of MRI in identification of the morphologic features of median nerve dysfunction after surgical release of the median nerve for carpal tunnel syndrome. Two blinded readers independently evaluated axial 1.5-T MR images for retinacular regrowth, morphologic characteristics of the median nerve, and presence of mass effect, fibrosis, and carpal tunnel decompression. All 47 patients (11 men, 36 women; mean age, 55 years; range, 27-81 years) had undergone open surgical release of the median nerve for carpal tunnel syndrome. Thirty-five patients had electromyographic evidence of recurrent carpal tunnel syndrome. The other 12 patients did not have electrophysiologic evidence of recurrent carpal tunnel syndrome and were the control group. A statistically significant difference between the recurrent carpal tunnel syndrome and control groups was found for fibrosis (p = 0.009), nerve enhancement (p = 0.04), and median nerve width (p = 0.008) and ratio (p = 0.01) at the pisiform level. MRI may be used in association with electromyography for accurate postoperative evaluation of the carpal tunnel.

MRI for identification of progression in brain tumors: from morphology to function

For monitoring of brain tumors, it is crucial to identify progression or treatment failure early during follow-up to change treatment schemes and, thereby, optimize patient outcome. In the past years, several areas within the field of magnetic resonance (MR) have seen considerable advances: modern contrast media, advanced morphologic approaches and several functional techniques, for example, in the visualization of tumor perfusion or tumor cell metabolism. This review presents these recent advances by introducing the different techniques and outlining their benefit for identification of progression in brain tumors, with a focus on gliomas, metastases and meningiomas. After radiotherapy, MR spectroscopy helps to more accurately discriminate between radiation necrosis and glioma progression. In low-grade gliomas, perfusion MR techniques enable a more sensitive detection of anaplastic transformation than conventional MRI. Modern contrast media, as well as diffusion tensor imaging, allow for an improved tumor delineation and assessment of tumor extension. We will also highlight the biological background of these techniques, their applicability and current limitations. In conclusion, modern MRI techniques have been developed that are on the doorstep to be integrated in clinical routine.

Significance of acute multiple brain infarction on diffusion-weighted imaging.

Diffusion-weighted imaging (DWI) is superior to conventional MRI in identification of small new ischemic lesions and discrimination of recent infarcts from old ones. Thus, this technique is useful in the detection of acute multiple brain infarcts (AMBI). We sought to determine the frequency and the topographical and etiologic patterns of AMBI detected on DWI. We studied 329 consecutive ischemic stroke patients who underwent DWI and MRI/MR angiography within 4 days of stroke onset. AMBI was defined as noncontiguous high signal intensities on DWI in >1 vascular territory. Stroke mechanism was determined according to the criteria of the Trial of Org 10172 in Acute Stroke Treatment (TOAST). We detected AMBI in 95 patients (28.9%). AMBI in anterior circulation was found in 62 cases: in 1 hemisphere in 42 (group A) and in bilateral hemispheres in 20 (group B). Twenty-two patients had AMBI in the posterior circulation (group C) and 11 in both anterior and posterior circulations (group D). The most frequent cause of stroke was large-artery atherosclerosis in groups A (33/42), B (9/20), and C (15/22) (P=0.02) and cardioembolism in group D (6/11) (P=0.02). Elevated fibrinogen or hematocrit was significantly associated with group B (P=0.01). In 9 patients in groups B and D, anatomic variations of anterior or posterior cerebral arteries or patent posterior communicating artery contributed to AMBI. Different topographical patterns of AMBI are associated with different vascular pathologies and stroke mechanisms. Hemorheologic abnormality or vascular anatomic variations may be contributing factors in the pathogenesis of AMBI in bilateral cerebral hemispheres or in both anterior and posterior circulations.