Moneal Shah

Exploratory use of cardiovascular magnetic resonance imaging in liver transplantation: a one-stop shop for preoperative cardiohepatic evaluation.

Background Preoperative cardiovascular risk stratification in orthotopic liver transplantation candidates has proven challenging due to limitations of current noninvasive modalities. Additionally, the preoperative workup is logistically cumbersome and expensive given the need for separate cardiac, vascular, and abdominal imaging. We evaluated the feasibility of a “one-stop shop” in a magnetic resonance suite, performing assessment of cardiac structure, function, and viability, along with simultaneous evaluation of thoracoabdominal vasculature and liver anatomy. Methods In this pilot study, patients underwent steady-state free precession sequences and stress cardiac magnetic resonance (CMR), thoracoabdominal magnetic resonance angiography, and abdominal magnetic resonance imaging (MRI) on a standard MRI scanner. Pharmacologic stress was performed using regadenoson, adenosine, or dobutamine. Viability was assessed using late gadolinium enhancement. Results Over 2 years, 51 of 77 liver transplant candidates (mean age, 56 years; 35% female; mean Model for End-stage Liver Disease score, 10.8; range, 6–40) underwent MRI. All referred patients completed standard dynamic CMR, 98% completed stress CMR, 82% completed late gadolinium enhancement for viability, 94% completed liver MRI, and 88% completed magnetic resonance angiography. The mean duration of the entire study was 72 min, and 45 patients were able to complete the entire examination. Among all 51 patients, 4 required follow-up coronary angiography (3 for evidence of ischemia on perfusion CMR and 1 for postoperative ischemia), and none had flow-limiting coronary disease. Nine proceeded to orthotopic liver transplantation (mean 74 days to transplantation after MRI). There were six ascertained mortalities in the nontransplant group and one death in the transplanted group. Explant pathology confirmed 100% detection/exclusion of hepatocellular carcinoma. No complications during CMR examination were encountered. Conclusions In this proof-of-concept study, it appears feasible to perform a comprehensive, efficient, and safe preoperative liver transplant imaging in a CMR suite—a one-stop shop, even in seriously ill patients.

Evaluation of cardiac valvular regurgitant lesions by cardiac MRI sequences: comparison of a four valve semi-quantitative vs. quantitative approach.

BACKGROUND AND AIM OF THE STUDY Cardiac magnetic resonance (CMR) imaging generally allows a more accurate and valid quantification of cardiac function, mass and regurgitant volumes than echocardiography. Although recent technological advancements in CMR have made the evaluation of cardiac valves more reliable, no studies have yet been conducted to compare semi-quantitative grading (SQG) using CMR steady-state free precession (SSFP) sequences with quantitative grading (QG) based on stroke volumes and phase-velocity mapping (PVM). It is proposed that the SQG of cardiac valvular regurgitations based on CMR SSFP sequences is feasible, and highly correlative with standard CMR QG methods. METHODS CMR data obtained between January 2007 and December 2011 was evaluated prospectively for valvular regurgitant lesions. Patients were included if they had right and left ventricular volumetrics based on CMR SSFP sequences and PVM across the aortic and pulmonic valves with reported regurgitant volumes and fractions. Patients were excluded if they had prosthetic valves, cardiac arrhythmias and intra-cardiac shunts. Regurgitant lesions were semi-quantitatively (visually) graded on a standard scale of 0 to 4 (trace, mild, moderate, moderate to severe, and severe) and compared with quantitative regurgitant fractions. Correlations were evaluated by Spearmans rho formula, and kappa for intra- and inter-observer variabilities were obtained on 30% of the study sample. RESULTS A total of 97 patients (58 males, 39 females; average age 55 +/- 18 years) representing 134 valvular regurgitations [mitral (MR), aortic (AR), tricuspid (TR), and pulmonary (PR)] were analyzed by semiquantitative and quantitative methods. The regurgitant lesions included 44 mitral, 50 aortic, 29 tricuspid, and 11 pulmonary. The correlation between SQR versus QG yielded the following results: 0.67, p < 0.001 (MR, r = 0.66, p < 0.001; AR, r = 0.68, p < 0.002; TR, r = 0.68, p = 0.001; PR, r = 0.70, p = 0.017). The results for QG versus SQG accounting for clinically significant differences of +/- 1 grade for the group were as follows: 0.95, p < 0.001 (MR, r = 0.91, p < 0.001; AR, r = 0.96, p < 0.001; TR, r = 0.99, p < 0.001; PR, r = 0.93, p < 0.001). No discrepancy between surgical regurgitation was present (3+ versus 4+). Weighted kappa results were 0.67 and 0.61 for intra- and inter-observer variabilities. CONCLUSION The visual assessment of cardiac regurgitant lesions is reliable, accurate and reproducible when compared to formal quantitative analysis via CMR. This confirms a robust role for CMR in assessing regurgitant lesions, particularly for surgical decision-making. These results were applicable to patients in sinus rhythm at the time of scanning.

Mid wall fibrosis on CMR with late gadolinium enhancement may predict prognosis for LVAD and transplantation risk in patients with newly diagnosed dilated cardiomyopathy—preliminary observations from a high-volume transplant centre

Patients with newly diagnosed dilated cardiomyopathy (DCM) and advanced heart failure have a very high morbidity and mortality with an unpredictable clinical course. We investigated the role of cardiovascular magnetic resonance (CMR) imaging using late gadolinium enhancement (LGE) in this cohort of high‐risk patients. We hypothesized that LGE has high prognostic value in primary DCM patients referred for possible transplantation/left ventricular assist device (LVAD) consideration.BACKGROUND Patients with newly diagnosed dilated cardiomyopathy (DCM) and advanced heart failure have a very high morbidity and mortality with an unpredictable clinical course. We investigated the role of cardiovascular magnetic resonance (CMR) imaging using late gadolinium enhancement (LGE) in this cohort of high-risk patients. We hypothesized that LGE has high prognostic value in primary DCM patients referred for possible transplantation/left ventricular assist device (LVAD) consideration. METHODS Over 49 consecutive months, 61 consecutives DCM patients were referred for standard CMR(1.5T, GE) to interrogate the LV pattern, distribution, and extent of LGE (MultiHance, Princeton, NJ). Inclusion criteria for a primary non-ischaemic DCM and EF <45% were met in 31 patients. DCM patients were categorized into: (i) presence of midwall LV stripe (+Stripe) and (ii) absence of midwall stripe (-Stripe) groups. Primary outcome was defined by the composite of death, need for LV assist device (LVAD), and urgent orthotopic cardiac transplantation (Tx) during a 12-month follow-up period. Kaplan-Meier survival analysis was conducted grouping patients by +Stripe and -Stripe. RESULTS There were no differences between groups for demographics, blood pressure, labs, baseline LVEF, NYHA class, or invasive haemodynamics. There were 18 patients (58%) with +Stripe. Nine events occurred: seven patients required urgent Tx and/or LVAD implantation and two patients died. The +Stripe categorization strongly predicted the need for LVAD, urgent Tx surgery, and death (log-rank = 9, P = 0.002). All the events occurred in the +Stripe patients with no MACE experienced in the -Stripe group. The -Stripe group experienced marked signs of improvement in LVEF (P = 0.01) at follow-up. LVEDD was predictive of need for LVAD/Tx and death by univariate analysis. Otherwise, no common clinical metric such as LVEF, LVEDV, RVEF, RVEDV, or any invasive haemodynamic parameter predicted MACE. CONCLUSIONS The presence of +Stripe on CMR is strongly predictive of LVAD, transplant need, and death during a 12-month follow-up period in DCM patients in this proof of concept study. All -Stripe patients survived without experiencing any events. Incorporating CMR imaging into routine clinical practice may have prognostic value in DCM patients; indicating conservative management in low-risk patients while expectantly managing high-risk patients.

Imaging the PM/AICD patient; fancy or fanatical?

Background Imaging patients with a pacemaker or AICD has always been taboo in the MRI environment. However, with current improvements in pacemaker lead and generator development along with very vigilant and knowledgeable personnel in pacemaker safety, MRI procedures can be implemented successfully. However, safe performance, not withstanding the risks, leads one to question if the results from the scans provide additional valuable clinical information to warrant the risk. Hypothesis: We propose that MRI imaging patients with a pacemaker can be crucial to establish clinical diagnosis. Methods A total of 25 patients were imaged on a GE CV/i Excite Version 12, 1.5 T system (GE, Milwaukee, WI). Three patients had an AICD, 4 patients had an AICD/Pacemaker, 2 patients had a single pacemaker lead and the remaining 16 patients had a complete pacemaker implantation. Each patient was performed in the dedicated Cardiac MRI Imaging Suite under the strict supervision of the Cardiologist. EP Lab personnel were present and reconfigured the pacemaker into an appropriate asynchronous mode under the guidance of the Cardiologist. The MRI scan sequences were selected such that the SAR level was lower or equal to 2.0 W/kg. to reduce additional heating to the device. Results All patients completed the procedure with no adverse events and the pacemaker was interrogated after the procedure by EP Lab and reprogrammed under the direction of the Cardiologist. Impedance, thresholds, amplitudes and shock impedances were unchanged pre to post scanning. The average MRI scan time was 20±55min. Regarding the population, of the 25 patients imaged, 17 (68%) were neurology cases and 8(32%) were cardiac cases. After reviewing the results from the 17 neurology cases and comparing the results from prior studies (CT, angio and/or myelogram) 14 (82%) out of the 17 patients benefited from having this procedure. 12 (70%) out of the 17 patients altered the diagnosis for a better outcome in patient care. The remaining 3(18%) patients did not show additional information that enhanced the diagnosis. The 8 cardiac cases were also compared to prior studies (heart cath, TEE, TTE and stress) and the outcome of all patients’ diagnosis was shown to be enhanced by the MRI imaging. In 4(50%) of the 8 patients CMR altered the prevailing clinical diagnosis. Thus, a total of 22 patients (88%) benefited by enhancement or alteration of the original diagnosis while 3(12%) patients did not provide any additional information. Conclusions The use of PM/AICD imaging in MRI remains controversial but as the lead/generator technology has improved, increased confidence in its use is found. Herein, we show that MRI procedures on carefully selected patients with pacemakers/AICD’s are beneficial and substantially enhance or alter patient diagnosis. We propose that not only are Pacemakers/AICD’s no longer taboo in the MRI environment but they can be markedly efficient with lifealtering and life-saving consequences. Funding None.

Pacemakers and AICDs in the Magnet; have we turned the corner?

Methods An evaluation of 157 consecutive patients with PM/ AICD’s who underwent MRI (GE CV/i, 1.5T, GE, Milwaukee,WI) over 10 years (90% <5 years) was performed. All had PM’s of which 12 were Bi-V PM’s while 31 patients also had an AICD. Specific criteria were followed to objectively determine if the diagnosis via MRI enhanced patient care. Accordingly, four questions were answered following scan interpretation by both the MRI technologist and MRI physician(s): 1) Did the primary diagnosis change? 2) Did the MRI provide additional information to the existing diagnosis? 3) Was the pre-MRI (tentative) diagnosis confirmed? 4) Did patient management change? If ‘Yes’ was answered to any of the above questions, it was considered that MRI was of value to patient diagnosis and/or impending therapy. Results The average MRI scan time was 20 ± 55 minutes. Regarding the population, of the 157 patients imaged, 114 (73%) were neurology/neurosurgery cases, 7 (4%) were musculoskeletal and 36 (23%) were cardiac/vascular cases. After reviewing the 114 neurology/neurosurgery cases, 21 (18%) demonstrated MRI not only provided additional information but also changed the original diagnosis and in turn, the course of medical treatment. In 79 patients (69%) MRI provided additional, complementary diagnostic information. Thus, for 100 (88%), MRI scan was of value to the final diagnosis. In only 14 (12%) patients imaged did MRI not provide further information but simply confirmed the original diagnosis. The 36 cardiac cases demonstrated that 5 patients (14%) the MRI provided additional information to change the original diagnosis and also patient management, 28 (77%) showed that complementary information was gathered while in 3(8%) the CMR was uninterpretable due to AICD artifact. In essence, 92% of the cardiac cases benefited by MRI performance. Finally, in the 7 musculoskeletal cases, MRI provided additional information in 6 (85%) and in 1(15%), changed patient management. Importantly, with careful attention to device reprogramming and scanner sequences, no safety issues were encountered and no adverse effects of undergoing the MRI scan were noted in any patient.

Gadolinium contrast agents: Over exposure?

Background MRI has dramatically changed the way we diagnose disease. With the introduction of contrast agents specifically for MRI, we were now able to see that which was ‘invisible’. Gadopentetate dimeglumine (Magnevist) was introduced over 20 years ago, since then many more agents with variable features have been introduced. Several newer agents have improved ‘relaxivity’ and some designated for organ specify use. Along with the increased administration of these agents, has been the emergence of an associated disease complex, Nephrogenic Systemic Fibrosis (NSF). This is an issue only in severely impaired renal function patients(eGFR<30 mL/ min/1.73 m). With increased understanding, the incidence of NSF has plummeted. Some agents such as MultiHance (gadobenate dimeglumine) have never had a single episode of NSF. Most recently a ‘new’ issue with gadolinium-based contrast agents has emerged; intracranial gadolinium deposition appearing presumably late only after multiple contrast MRI’s. McDonald and Radbruch, noted gadolinium in pts’ brain tissue especially in the globus pallidus, thalamus, dentate nucleus and pons in pts with at least four contrast exams. More troubling, as opposed to NSF, this finding was found in pts with preserved GFR (eGFR≥49 mL/min/ 1.73 m).

Echocardiography and cardiovascular MRI entwined within the imaging domain; uniting the two. A compendium for the echocardiographer

A review of the unique and complementary roles echocardiography and cardiovascular MRI provide to the clinician. A focus on the physics of each modality as well as imaging of the left ventricle.

Cardio-hepatic risk assessment by CMR imaging in liver transplant candidates

The preoperative workup of orthotopic liver transplantation (OLT) patients is practically complex given the need for multiple imaging modalities. We recently demonstrated in our proof‐of‐concept study the value of a one‐stop‐shop approach using cardiovascular MRI (CMR) to address this complex problem. However, this approach requires further validation in a larger cohort, as detection of hepatocellular carcinoma (HCC) as well as cardiovascular risk assessment is critically important in these patients. We hypothesized that coronary risk assessment and HCC detectability is acceptable using the one‐stop‐shop CMR approach.

Type I Kounis syndrome variant: A case report and literature review

Kounis syndrome defined as the occurrence of acute coronary syndrome in the setting of allergic reaction due to mast cells activation and inflammatory mediators release that induces coronary vasospasm, plaque erosion, or even stent thrombosis. A 25-year-old postpartum female with asthma and recurrent episodes of chest pain was admitted with ST-segment elevation myocardial infarction in the setting of coronary artery spasms. The patient was started on calcium channel blockers and nitrite-based medication with no improvement. She was noted to have eosinophilia and initiation of corticosteroid-based regimen lead to resolution of chest pain episodes and normalization of eosinophilia. Kounis syndrome should be considered in young patients with chest pain. Coronary vasodilators are considered as the first-line of treatment. The use of corticosteroids has been described in the literature in severe or refractory cases.

Physiologic left ventricular ejection efficiency assessed at the level of the aorta

Methods Vascular ejection efficiency (VEE) is proportional to the dimensionless ratio of aortic diameter to wavelength of the transmitted blood pulse. The wavelength of ejected blood is proportional to blood wave velocity divided by blood wave frequency measured using phase velocity mapping (PVM) applied to the ascending aorta. Left ventricular function and aortic PVM data were retrospectively obtained in 118 patients who underwent CMR scanning as a clinical routine. The LV end-diastolic and end-systolic volumes were measured using manually drawn contours for a contiguous stack of LV slices. The aortic area was measured from the PVM images along with the average velocity, taken as a measure of blood wave velocity (not to be confused with the more common pulse wave velocity), the end-systolic time was taken as the pulse length and aortic area instead of diameter to yield the VEE index: VEE = Aortic Area × End systolic time / Average blood velocity The VEE was calculated and plotted against the ventricular measures of EF and VVC.