Vikram Kurra

Pre-Procedural Imaging of Aortic Root Orientation and Dimensions: Comparison Between X-Ray Angiographic Planar Imaging and 3-Dimensional Multidetector Row Computed Tomography

OBJECTIVES We sought to examine whether contrast-enhanced multidetector row computed tomography (MDCT) allows prediction of X-ray angiographic planes for the root angiogram in the context of transcatheter aortic valve implantation. BACKGROUND Understanding of aortic root orientation relative to the body axis is critical for precise positioning of the stent/valve during transcatheter aortic valve implantation. METHODS Forty patients with severe aortic stenosis underwent conventional X-ray angiography and contrast-enhanced MDCT of the aortic root. Oblique MDCT images of the aortic root, corresponding to X-ray angiographic left anterior oblique (LA)/right anterior oblique (RAO) projections, were created. The cranial/caudal angulation was compared between angiographic and reformatted MDCT images. In addition, root diameter measurements were compared. RESULTS The cranial angulation in the LAO X-ray angiograms (mean LAO: 39+/- 8, n = 38) and matched MDCT images were not significantly different (cranial: 25 +/- 7 vs. 23 +/- 8; p = 0.214). There was a small but significant difference between the caudal angulation in the RAO angiogram (mean RAO: 25 +/- 5, n = 40) and matched CT images (caudal: 21 +/- 9 vs. 29 +/- 10; p = 0.002). The annulus diameter in the LAO projection was not significantly different between X-ray angiography and contrast-enhanced MDCT (2.3 +/- 0.3 vs. 2.4 +/- 0.3; p = 0.052), whereas there was a small but significant difference in the annulus diameter in RAO projections between angiography and MDCT (2.4 +/- 0.3 vs. 2.2 +/- 0.3; p = 0.029). CONCLUSIONS Pre-procedural contrast-enhanced MDCT imaging of the aortic root allows prediction of X-ray angiographic planes and contributes to planning of the transcatheter aortic valve implantation.

Prevalence of significant peripheral artery disease in patients evaluated for percutaneous aortic valve insertion: Preprocedural assessment with multidetector computed tomography

OBJECTIVES Percutaneous aortic valve insertion is an emerging treatment option for selected patients with severe aortic stenosis and may be done from a transfemoral or transapical approach. Concomitant atherosclerotic peripheral artery disease limits transfemoral access. We evaluated the potential role of multidetector computed tomography in preoperative assessment of vascular anatomy. METHODS Consecutive patients with severe aortic stenosis were included. Contrast-enhanced computed tomographic angiography of the thoracic and abdominal aorta and iliofemoral arteries was performed. Criteria of unfavorable iliofemoral anatomy were defined as a minimal luminal diameter of the common iliac, external iliac, or common femoral arteries of less than 8 mm, presence of greater than 60% circumferential calcification at the external-internal iliac bifurcation, and severe angulation between the common and external iliac arteries (< 90 degrees ). The prevalence of these criteria was evaluated and infrarenal aortic and iliofemoral arterial anatomy was compared in the groups with and without peripheral artery disease for any of these criteria. RESULTS One hundred patients (79 +/- 9 years, 59% male) were included. A total of 35 (35%) patients had at least one criterion of unsuitable iliofemoral anatomy, including 27 patients with small minimal luminal diameter (<8 mm), 12 patients with severe circumferential calcification at the iliac bifurcation (>60%), and 4 with severe angulation of the iliac arteries (<90 degrees ). CONCLUSIONS Significant atherosclerotic peripheral artery disease is common in the high-risk patient population currently evaluated for percutaneous aortic valve insertion. Computed tomography allows identification of patients with iliofemoral anatomy unfavorable for the transfemoral approach to percutaneous aortic valve insertion.

Aortic root morphology in patients undergoing percutaneous aortic valve replacement: Evidence of aortic root remodeling

OBJECTIVE Percutaneous aortic valve replacement is an emerging therapy for selected patients with severe aortic stenosis. Preoperative imaging of the aortic root facilitates sizing and deployment of the percutaneous aortic valve replacement device. We compared morphologic characteristics of the aortic root in patients with aortic stenosis versus elderly gender-matched controls using multidetector computed tomography. METHODS Twenty-five consecutive subjects with severe calcific aortic stenosis referred for percutaneous aortic valve replacement and 25 elderly gender-matched controls were scanned on a Siemens Definition Dual Source (Siemens Medical, Forchheim, Germany) multidetector computed tomography scanner. Distances from the valve annulus to the coronary artery ostia and sinotubular junction, dimensions of the aortic root, and characteristics of the valve cusps were determined. RESULTS Subjects with aortic stenosis had reduced distance from the aortic valve annulus to the inferior margins of the left and right coronary artery ostium and sinotubular junction compared with controls. There were no significant differences in cross-sectional dimensions of the aortic root. CONCLUSION The distance from the aortic valve annulus to the coronary artery ostia and sinotubular junction is reduced in patients with aortic stenosis compared with controls. This finding suggests that longitudinal remodeling of the aortic root occurs in calcific aortic stenosis and has implications for the design and deployment of percutaneous aortic valve replacement devices.

Extent of Thoracic Aortic Atheroma Burden and Long-Term Mortality After Cardiothoracic Surgery : A Computed Tomography Study

OBJECTIVES We hypothesized that the extent of aortic atheroma of the entire thoracic aorta, determined by pre-operative multidetector-row computed tomographic angiography (MDCTA), is associated with long-term mortality following nonaortic cardiothoracic surgery. BACKGROUND In patients evaluated for cardiothoracic surgery, presence of severe aortic atheroma is associated with adverse short- and long-term post-operative outcome. However, the relationship between aortic plaque burden and mortality remains unknown. METHODS We reviewed clinical and imaging data from all patients who underwent electrocardiographic-gated contrast-enhanced MDCTA prior to coronary bypass or valvular heart surgery at our institution between 2002 and 2008. MDCTA studies were analyzed for thickness and circumferential extent of aortic atheroma in 5 segments of the thoracic aorta. A semiquantitative total plaque-burden score (TPBS) was calculated by assigning a score of 1 to 3 to plaque thickness and to circumferential plaque extent. When combined, this resulted in a score of 0 to 6 for each of the 5 segments and, hence, an overall score from 0 to 30. The primary end point was all-cause mortality during long-term follow-up. RESULTS A total of 862 patients (71% men, 67.8 years) were included and followed over a mean period of 25 ± 16 months. The mean TPBS was 8.6 (SD: ±6.0). The TPBS was a statistically significant predictor of mortality (p < 0.0001) while controlling for baseline demographics, cardiovascular risk factors, and type of surgery including reoperative status. The estimated hazard ratio for TPBS was 1.08 (95% confidence interval: 1.045 to 1.12). Other independent predictors of mortality were glomerular filtration rate (p = 0.015), type of surgery (p = 0.007), and peripheral artery disease (p = 0.03). CONCLUSIONS Extent of thoracic aortic atheroma burden is independently associated with increased long-term mortality in patients following cardiothoracic surgery. Although our data do not provide definitive evidence, they suggest a relationship to the systemic atherosclerotic disease process and, therefore, have important implications for secondary prevention in post-operative rehabilitation programs.

Effects of Surgical Ventricular Restoration on Left Ventricular Contractility Assessed by a Novel Contractility Index in Patients With Ischemic Cardiomyopathy

A pressure-normalized left ventricular (LV) wall stress (dsigma*/dt(max)) was recently reported as a load-independent index of LV contractility. We hypothesized that this novel contractility index might demonstrate improvement in LV contractile function after surgical ventricular restoration (SVR) using magnetic resonance imaging. A retrospective analysis of magnetic resonance imaging data of 40 patients with ischemic cardiomyopathy who had undergone coronary artery bypass grafting with SVR was performed. LV volumes, ejection fraction, global systolic and diastolic sphericity, and dsigma*/dt(max) were calculated. After SVR, a decrease was found in end-diastolic and end-systolic volume indexes, whereas LV ejection fraction increased from 26% +/- 7% to 31% +/- 10% (p <0.001). LV mass index and peak normalized wall stress were decreased, whereas the sphericity index (SI) at end-diastole increased, indicating that the left ventricle became more spherical after SVR. LV contractility index dsigma*/dt(max) improvement (from 2.69 +/- 0.74 to 3.23 +/- 0.73 s(-1), p <0.001) was associated with shape change as evaluated by the difference in SI between diastole and systole (r = 0.32, p <0.001, preoperative; r = 0.23, p <0.001, postoperative), but not with baseline LV SI. In conclusion, SVR excludes akinetic LV segments and decreases LV wall stress. Despite an increase in sphericity, LV contractility, as determined by dsigma*/dt(max), actually improves. A complex interaction of LV maximal flow rate and LV mass may explain the improvement in LV contractility after SVR. Because dsigma*/dt(max) can be estimated from simple noninvasive measurements, this underscores its clinical utility for assessment of contractile function with therapeutic intervention.

Typical and atypical metastatic sites of recurrent endometrial carcinoma

Abstract The purpose of this article is to illustrate the imaging findings of typical and atypical metastatic sites of recurrent endometrial carcinoma. Typical sites include local pelvic recurrence, pelvic and para-aortic nodes, peritoneum, and lungs. Atypical sites include extra-abdominal lymph nodes, liver, adrenals, brain, bones and soft tissue. It is important for radiologists to recognize the typical and atypical sites of metastases in patients with recurrent endometrial carcinoma to facilitate earlier diagnosis and treatment.

MRI for evaluation of myeloid sarcoma in adults: a single-institution 10-year experience.

OBJECTIVE The purpose of this study was to evaluate the utilization and role of MRI in the management of myeloid sarcoma in adults. MATERIALS AND METHODS A retrospective study of 69 patients with pathologically proven myeloid sarcoma included 25 patients (16 men, nine women; mean age, 55 years; range, 22-78 years) who underwent pretreatment MRI at our institution from January 2001 to October 2011. A total of 71 MRI examinations were evaluated by two radiologists in consensus. RESULTS A total of 41 sites of involvement of myeloid sarcoma were noted, most commonly bone (13/25, 52%), muscle (7/25, 28%), CNS (6/25, 24%), and head and neck (6/25, 24%). Nineteen sites were noted on MR images obtained for evaluation of a new sign or symptom, most commonly musculoskeletal (11 sites) and CNS (six sites). Fifteen sites were noted on MR images obtained for further evaluation of a previously detected abnormality, most commonly in the abdomen and pelvis (seven sites). Seven lesions were incidentally found on MR images obtained for other myeloid sarcoma-related indications, most commonly in the head and neck (three lesions) and musculoskeletal system (three lesions). The mean size of measurable lesions was 5.6 cm (range, 1-20 cm). Compared with muscle, the lesions were isointense (31/41, 75.6%) or hypointense (10/41, 24.4%) on T1-weighted images and mildly hyperintense (39/41, 95.1%) on T2-weighted images and had homogeneous enhancement (29/38, 76.3%). CONCLUSION In our experience, MRI was most often used for evaluation of bone, muscle, the CNS, and the head and neck region. MRI is useful for evaluation of new musculoskeletal and CNS findings and for further evaluation of known abdominopelvic masses. Incidental findings are often musculoskeletal or in the soft tissues of the head and neck.

Comparison of performance of various tumour response criteria in assessment of regorafenib activity in advanced gastrointestinal stromal tumours after failure of imatinib and sunitinib

PURPOSE To compare performance of various tumour response criteria (TRCs) in assessment of regorafenib activity in patients with advanced gastrointestinal stromal tumour (GIST) with prior failure of imatinib and sunitinib. METHODS Twenty participants in a phase II trial received oral regorafenib (median duration 47 weeks; interquartile range (IQR) 24-88) with computed tomography (CT) imaging at baseline and every two months thereafter. Tumour response was prospectively determined on using Response Evaluation Criteria in Solid Tumours (RECIST) 1.1, and retrospectively reassessed for comparison per RECIST 1.0, World Health Organization (WHO) and Choi criteria, using the same target lesions. Clinical benefit rate [CBR; complete or partial response (CR or PR) or stable disease (SD)≥16 weeks] and progression-free survival (PFS) were compared between various TRCs using kappa statistics. Performance of TRCs in predicting overall survival (OS) was compared by comparing OS in groups with progression-free intervals less than or greater than 20 weeks by each TRC using c-statistics. RESULTS PR was more frequent by Choi (90%) than RECIST 1.1, RECIST 1.0 and WHO (20% each), however, CBR was similar between various TRCs (overall CBR 85-90%, 95-100% agreement between all TRC pairs). PFS per RECIST 1.0 was similar to RECIST 1.1 (median 44 weeks versus 58 weeks), and shorter for WHO (median 34 weeks) and Choi (median 24 weeks). With RECIST 1.1, RECIST 1.0 and WHO, there was moderate concordance between PFS and OS (c-statistics 0.596-0.679). Choi criteria had less favourable concordance (c-statistic 0.506). CONCLUSIONS RECIST 1.1 and WHO performed somewhat better than Choi criteria as TRC for response evaluation in patients with advanced GIST after prior failure on imatinib and sunitinib.

Immune Checkpoint Inhibitor Cancer Therapy: Spectrum of Imaging Findings

Immune checkpoint inhibitors are a new class of cancer therapeutics that have demonstrated striking successes in a rapid series of clinical trials. Consequently, these drugs have dramatically increased in clinical use since being first approved for advanced melanoma in 2011. Current indications in addition to melanoma are non-small cell lung cancer, head and neck squamous cell carcinoma, renal cell carcinoma, urothelial carcinoma, and classical Hodgkin lymphoma. A small subset of patients treated with immune checkpoint inhibitors undergoes an atypical treatment response pattern termed pseudoprogression: New or enlarging lesions appear after initiation of therapy, thereby mimicking tumor progression, followed by an eventual decrease in total tumor burden. Traditional response standards applied at the time of initial increase in tumor burden can falsely designate this as treatment failure and could lead to inappropriate termination of therapy. Currently, when new or enlarging lesions are observed with immune checkpoint inhibitors, only follow-up imaging can help distinguish patients with pseudoprogression from the large majority in whom this observation represents true treatment failure. Furthermore, the unique mechanism of immune checkpoint inhibitors can cause a distinct set of adverse events related to autoimmunity, which can be severe or life threatening. Given the central role of imaging in cancer care, radiologists must be knowledgeable about immune checkpoint inhibitors to correctly assess treatment response and expeditiously diagnose treatment-related complications. The authors review the molecular mechanisms and clinical applications of immune checkpoint inhibitors, the current strategy to distinguish pseudoprogression from progression, and the imaging appearances of common immune-related adverse events. ©RSNA, 2017.

Imaging features and metastatic pattern of non-IVC retroperitoneal leiomyosarcomas: are they different from IVC leiomyosarcomas?

Purpose The purposes of this study were to describe the imaging features and metastatic pattern of non–inferior vena cava (IVC) retroperitoneal leiomyosarcomas (non–IVC LMS) and to compare them with those of IVC leiomyosarcomas (IVC LMS) to assess any differences between the 2 groups. Materials and Methods In this institutional review board–approved, Health Insurance Portability and Accountability Act–compliant retrospective study, all 56 patients with pathologically confirmed primary retroperitoneal leiomyosarcoma (34 non–IVC LMS and 22 IVC LMS) seen at our tertiary cancer center during a 10-year period were included. All available imaging of primary tumor (18 non–IVC LMS and 19 IVC LMS) and follow-up imaging studies (on all 56 patients) were reviewed in consensus by 2 fellowship-trained oncoradiologists. Imaging features and metastatic spread of non–IVC LMS were described and compared with those of IVC LMS. Continuous variables were compared using the Student t test, binary variables with the Fisher exact test, and survival using the log-rank test. Results Non–inferior vena cava retroperitoneal leiomyosarcomas had a mean size of 11.3 cm (range, 3.7–27 cm) and most commonly occurred in the perirenal space (16/18). Primary tumors were hyperattenuating to muscle (11/18) and showed heterogeneous enhancement (17/18). Lungs (22/34), peritoneum (18/34), and liver (18/34) were the most common metastatic sites. There was no significant difference between the imaging features and metastatic pattern of non–IVC and IVC LMS. Although non–IVC LMS presented at a more advanced stage (P < 0.002), there was statistically non–significant trend toward better median survival of non–IVC LMS (P = 0.07). Conclusions Non–inferior vena cava retroperitoneal leiomyosarcomas are large heterogeneous tumors arising in the perirenal space and frequently metastasize to lungs, peritoneum, and liver. From a radiologist’s perspective, non–IVC LMS behave similar to IVC-LMS.