Accuracy of Noncontrast T2 SPACE in Active MS Cord Lesion Detection.

BACKGROUND AND PURPOSE: The diagnosis of active MS lesions is often based on postgadolinium T1-weighted MR imaging. Recent studies suggest a risk of IV gadolinium to patients, predominantly based on gadolinium deposition in tissue. Noncontrast sequences have shown promise in MS diagnosis, but none differentiate acute from chronic MS lesions. We hypothesized that 3D T2 sampling perfection with application-optimized contrasts by using different flip angle evolution (SPACE) MR imaging can help detect and differentiate active-versus-chronic MS lesions without the need for IV contrast. MATERIALS AND METHODS: In this single-center retrospective study, 340 spinal MR imaging cases of MS were collected in a 24-month period. Two senior neuroradiologists blindly and independently reviewed postcontrast T1-weighted sagittal and T2-SPACE sagittal images for the presence of MS lesions, associated cord expansion/atrophy on T2-SPACE, and enhancement on postcontrast T1WI. Discrepancies were resolved by consensus between the readers. Sensitivity, specificity, and accuracy of T2-SPACE compared with postcontrast T1WI were computed, and interobserver agreement was calculated. RESULTS: The sensitivity of lesion detection on T2-SPACE was 85.71%, 95% CI, 63.66%-96.95%; with a specificity of 93.52%, 95% CI, 90.06%-96.05%; and an accuracy of 92.99%, 95% CI, 89.58%-95.56. Additionally, 16/21 (84.2%) acute enhancing cord lesions showed cord expansion on T2-SPACE. The interobserver agreement was 92%. CONCLUSIONS: Our study shows that T2-SPACE facilitates noncontrast detection of acute MS lesions with high accuracy compared with postcontrast T1WI and with high interobserver agreement. The lack of gadolinium use provides an advantage, bypassing any potential adverse effects of repetitive contrast administration.

Palpable Lumps after Mastectomy: Radiologic-Pathologic Review of Benign and Malignant Masses.

Patients who have undergone mastectomy, with or without reconstruction, are not universally screened with mammography or US. Therefore, clinical breast examination by the physician and patient-detected palpable abnormalities are crucial for detecting breast cancer or recurrence. Diagnostic US is the first-line modality for evaluation of postmastectomy palpable masses, with occasional adjunct use of diagnostic mammography for confirming certain benign masses. In the setting of a negative initial imaging evaluation with continued clinical concern, diagnostic MRI may aid in improving sensitivity. Knowledge of the typical multimodality imaging appearances and locations of malignant palpable abnormalities-such as invasive carcinoma recurrence, cancer in residual breast tissue, radiation-induced sarcoma, and metastatic disease-is crucial in diagnosis and treatment of these entities. In addition, familiarity with the range of benign palpable postmastectomy processes-including fat necrosis, fat graft, seroma, granuloma, neuroma, fibrosis, and infection-may help avoid unnecessary biopsies and reassure patients. The authors review common and rare benign and malignant palpable masses in mastectomy patients, describe multimodality diagnostic imaging evaluation of each entity, review radiologic and pathologic correlation, and acquaint the radiologist with management when these findings are encountered. ©RSNA, 2021.

Optoacoustic Breast Imaging: Imaging-Pathology Correlation of Optoacoustic Features in Benign and Malignant Breast Masses.

OBJECTIVE: Optoacoustic ultrasound breast imaging is a fused anatomic and functional modality that shows morphologic features, as well as hemoglobin amount and relative oxygenation within and around breast masses. The purpose of this study is to investigate the positive predictive value (PPV) of optoacoustic ultrasound features in benign and malignant masses. SUBJECTS AND METHODS: In this study, 92 masses assessed as BI-RADS category 3, 4, or 5 in 94 subjects were imaged with optoacoustic ultrasound. Each mass was scored by seven blinded independent readers according to three internal features in the tumor interior and two external features in its boundary zone and periphery. Mean and median optoacoustic ultrasound scores were compared with histologic findings for biopsied masses and nonbiopsied BI-RADS category 3 masses, which were considered benign if they were stable at 12-month follow-up. Statistical significance was analyzed using a two-sided Wilcoxon rank sum test with a 0.05 significance level. RESULTS: Mean and median optoacoustic ultrasound scores for all individual internal and external features, as well as summed scores, were higher for malignant masses than for benign masses (p < 0.0001). High external scores, indicating increased hemoglobin and deoxygenation and abnormal vessel morphologic features in the tumor boundary zone and periphery, better distinguished benign from malignant masses than did high internal scores reflecting increased hemoglobin and deoxygenation within the tumor interior. CONCLUSION: High optoacoustic ultrasound scores, particularly those based on external features in the boundary zone and periphery of breast masses, have high PPVs for malignancy and, conversely, low optoacoustic ultrasound scores have low PPV for malignancy. The functional component of optoacoustic ultrasound may help to overcome some of the limitations of morphologic overlap in the distinction of benign and malignant masses.

Downgrading and Upgrading Gray-Scale Ultrasound BI-RADS Categories of Benign and Malignant Masses With Optoacoustics: A Pilot Study.

OBJECTIVE: False-positive findings remain challenging in breast imaging. This study investigates the incremental value of optoacoustic imaging in improving BI-RADS categorization of breast masses at ultrasound. SUBJECTS AND METHODS: The study device is an optoacoustic breast imaging device with a handheld duplex laser and internal gray-scale ultrasound probe, fusing functional and morphologic information (optoacoustic ultrasound). In this prospective multisite study, breast masses assessed as BI-RADS category 3, 4A, 4B, 4C, or 5 by site radiologists underwent both gray-scale ultrasound and optoacoustic imaging with the study device. Independent reader radiologists assessed internal gray-scale ultrasound and optoacoustic ultrasound features for each mass and assigned a BI-RADS category. The percentage of mass reads for which optoacoustic ultrasound resulted in a downgrade or upgrade of BI-RADS category relative to internal gray-scale ultrasound was determined. RESULTS: Of 94 total masses, 39 were biopsy-proven malignant, 44 were biopsy-proven benign, and 11 BI-RADS category 3 masses were stable at 12-month follow-up. The sensitivity of both optoacoustic ultrasound and internal gray-scale ultrasound was 97.1%. The specificity was 44.3% for optoacoustic ultrasound and 36.4% for internal gray-scale ultrasound. Using optoacoustic ultrasound, 41.7% of benign masses or BI-RADS category 3 masses that were stable at 12-month follow-up were downgraded to BI-RADS category 2 by independent readers; 36.6% of masses assigned BI-RADS category 4A were downgraded to BI-RADS category 3 or 2, and 10.1% assigned BI-RADS category 4B were downgraded to BI-RADS category 3 or 2. Using optoacoustic ultrasound, independent readers upgraded 75.0% of the malignant masses classified as category 4A, 4B, 4C, or 5, and 49.4% of the malignant masses were classified as category 4B, 4C, or 5. CONCLUSION: Optoacoustic ultrasound resulted in BI-RADS category downgrading of benign masses and upgrading of malignant masses compared with gray-scale ultrasound.

A Pivotal Study of Optoacoustic Imaging to Diagnose Benign and Malignant Breast Masses: A New Evaluation Tool for Radiologists.

Purpose To compare the diagnostic utility of an investigational optoacoustic imaging device that fuses laser optical imaging (OA) with grayscale ultrasonography (US) to grayscale US alone in differentiating benign and malignant breast masses. Materials and Methods This prospective, 16-site study of 2105 women (study period: 12/21/2012 to 9/9/2015) compared Breast Imaging Reporting and Data System (BI-RADS) categories assigned by seven blinded independent readers to benign and malignant breast masses using OA/US versus US alone. BI-RADS 3, 4, or 5 masses assessed at diagnostic US with biopsy-proven histologic findings and BI-RADS 3 masses stable at 12 months were eligible. Independent readers reviewed US images obtained with the OA/US device, assigned a probability of malignancy (POM) and BI-RADS category, and locked results. The same independent readers then reviewed OA/US images, scored OA features, and assigned OA/US POM and a BI-RADS category. Specificity and sensitivity were calculated for US and OA/US. Benign and malignant mass upgrade and downgrade rates, positive and negative predictive values, and positive and negative likelihood ratios were compared. Results Of 2105 consented subjects with 2191 masses, 100 subjects (103 masses) were analyzed separately as a training population and excluded. An additional 202 subjects (210 masses) were excluded due to technical failures or incomplete imaging, 72 subjects (78 masses) due to protocol deviations, and 41 subjects (43 masses) due to high-risk histologic results. Of 1690 subjects with 1757 masses (1079 [61.4%] benign and 678 [38.6%] malignant masses), OA/US downgraded 40.8% (3078/7535) of benign mass reads, with a specificity of 43.0% (3242/7538, 99% confidence interval [CI]: 40.4%, 45.7%) for OA/US versus 28.1% (2120/7543, 99% CI: 25.8%, 30.5%) for the internal US of the OA/US device. OA/US exceeded US in specificity by 14.9% (P < .0001; 99% CI: 12.9, 16.9%). Sensitivity for biopsied malignant masses was 96.0% (4553/4745, 99% CI: 94.5%, 97.0%) for OA/US and 98.6% (4680/4746, 99% CI: 97.8%, 99.1%) for US (P < .0001). The negative likelihood ratio of 0.094 for OA/US indicates a negative examination can reduce a maximum US-assigned pretest probability of 17.8% (low BI-RADS 4B) to a posttest probability of 2% (BI-RADS 3). Conclusion OA/US increases the specificity of breast mass assessment compared with the device internal grayscale US alone. Online supplemental material is available for this article. © RSNA, 2017.

Stereotactic Accelerated Partial Breast Irradiation for Early-Stage Breast Cancer: Rationale, Feasibility, and Early Experience Using the CyberKnife Radiosurgery Delivery Platform.

PURPOSE: The efficacy of accelerated partial breast irradiation (APBI) utilizing brachytherapy or conventional external beam radiation has been studied in early-stage breast cancer treated with breast-conserving surgery. Data regarding stereotactic treatment approaches are emerging. The CyberKnife linear accelerator enables excellent dose conformality to target structures while adjusting for target and patient motion. We report our institutional experience on the technical feasibility and rationale for stereotactic accelerated partial breast irradiation (SAPBI) delivery using the CyberKnife radiosurgery system. METHODS: Ten patients completed CyberKnife SAPBI (CK-SAPBI) in 2013 at Georgetown University Hospital. Four gold fiducials were implanted around the lumpectomy cavity prior to treatment under ultrasound guidance. The synchrony system tracked intrafraction motion of the fiducials. The clinical target volume was defined on contrast enhanced CT scans using surgical clips and post-operative changes. A 5 mm expansion was added to create the planning treatment volume (PTV). A total dose of 30 Gy was delivered to the PTV in five consecutive fractions. Target and critical structure doses were assessed as per the National Surgical Adjuvant Breast and Bowel Project B-39 study. RESULTS: At least three fiducials were tracked in 100% of cases. The Mean treated PTV was 70 cm(3) and the mean prescription isodose line was 80%. Mean dose to target volumes and constraints are as follows: 100% of the PTV received the prescription dose (PTV30). The volume of the ipsilateral breast receiving 30 Gy (V30) and above 15 Gy (V > 15) was 14 and 31%, respectively. The ipsilateral lung volume receiving 9 Gy (V9) was 3%, and the contralateral lung volume receiving 1.5 Gy (V1.5) was 8%. For left-sided breast cancers, the volume of heart receiving 1.5 Gy (V1.5) was 31%. Maximum skin dose was 36 Gy. At a median follow-up of 1.3 years, all patients have experienced excellent/good breast cosmesis outcomes, and no breast events have been recorded. CONCLUSION: CyberKnife stereotactic accelerated partial breast irradiation is an appealing technique for partial breast irradiation offering improvements over existing APBI techniques. Our early findings indicate that CK-SAPBI delivered in five daily fractions is feasible, well tolerated, and is a reliable platform for delivering APBI.

Effectiveness of a Rapid Lumbar Spine MRI Protocol Using 3D T2-Weighted SPACE Imaging Versus a Standard Protocol for Evaluation of Degenerative Changes of the Lumbar Spine.

OBJECTIVE: Reducing lumbar spine MRI scanning time while retaining diagnostic accuracy can benefit patients and reduce health care costs. This study compares the effectiveness of a rapid lumbar MRI protocol using 3D T2-weighted sampling perfection with application-optimized contrast with different flip-angle evolutions (SPACE) sequences with a standard MRI protocol for evaluation of lumbar spondylosis. MATERIALS AND METHODS: Two hundred fifty consecutive unenhanced lumbar MRI examinations performed at 1.5 T were retrospectively reviewed. Full, rapid, and complete versions of each examination were interpreted for spondylotic changes at each lumbar level, including herniations and neural compromise. The full examination consisted of sagittal T1-weighted, T2-weighted turbo spin-echo (TSE), and STIR sequences; and axial T1- and T2-weighted TSE sequences (time, 18 minutes 40 seconds). The rapid examination consisted of sagittal T1- and T2-weighted SPACE sequences, with axial SPACE reformations (time, 8 minutes 46 seconds). The complete examination consisted of the full examination plus the T2-weighted SPACE sequence. Sensitivities and specificities of the full and rapid examinations were calculated using the complete study as the reference standard. RESULTS: The rapid and full studies had sensitivities of 76.0% and 69.3%, with specificities of 97.2% and 97.9%, respectively, for all degenerative processes. Rapid and full sensitivities were 68.7% and 66.3% for disk herniation, 85.2% and 81.5% for canal compromise, 82.9% and 69.1% for lateral recess compromise, and 76.9% and 69.7% for foraminal compromise, respectively. CONCLUSION: Isotropic SPACE T2-weighted imaging provides high-quality imaging of lumbar spondylosis, with multiplanar reformatting capability. Our SPACE-based rapid protocol had sensitivities and specificities for herniations and neural compromise comparable to those of the protocol without SPACE. This protocol fits within a 15-minute slot, potentially reducing costs and discomfort for a large subgroup of patients.

Predictors of vestibular schwannoma growth in patients with neurofibromatosis Type 2.

OBJECT: The results of two longitudinal studies of growth rates of vestibular schwannomas (VSs) in patients with neurofibromatosis Type 2 (NF2) differ as to whether VS growth rates decrease or increase with increasing patient age. The authors undertook this study to assess the relationship between VS growth rates and patient age and type of constitutional NF2 mutation; they also examined variability in VS growth rates among multiple patients in families with NF2. METHODS: Gadolinium-enhanced magnetic resonance images obtained in 18 patients with inherited NF2 from 11 unrelated families were retrospectively analyzed. The patients had been observed for a median of 4 years. Volumes of the VSs were measured using a two-component box model (intrameatal and extrameatal parts measured separately). Single-strand conformation polymorphism analysis and Southern blot analysis were used to identify constitutional NF2 mutations. Growth rates of the VSs were highly variable, but tended to decrease with increasing patient age both at onset of signs or symptoms of NF2 (r2 = 0.35, p = 0.026) and at diagnosis (r2 = 0.33, p = 0.012). The VS growth rates did not vary significantly with the type of constitutional NF2 mutation or the number of non-VS cerebral or spinal tumors. The VS growth rates were highly variable within families and did not correspond to clinical indices of NF2 disease severity, such as patient age at symptom onset and the number of non-VS cerebral and spinal tumors. CONCLUSIONS: The growth rates of VSs in patients with NF2 are highly variable, but tend to decrease with increasing patient age. Clinical treatment of multiple patients in families with NF2 cannot be based on the expectations of similar VS growth rates, even when other clinical aspects of disease severity are similar.