Assessment of Left Ventricular Structural Abnormalities

  • Key Point

  • The high spatial resolution and excellent field of view of CCT enables it to depict a range of myocardial, septal, and other structural lesions.

Myocardial Crypts

Myocardial crypts (or clefts) have been defined as discrete V-shaped extensions of the blood pool inserting more than 50% into the compact myocardial wall that tend to be less visible during systole and are not associated with local hypokinesis or dyskinesia. Increased prevalence of crypts has been reported in carriers of the gene for hypertrophic cardiomyopathy (as much as 81%). However, myocardial crypts also are seen in normal subjects, so their precise significance has yet to be determined.

For CCT images of myocardial crypts, see Figures 20-1 and 20-2 ;

Figure 20-1

Multiple composite images from a cardiac CT study in a patient with hypertrophic cardiomyopathy demonstrating a basal inferior crypt and an enlarged left atrium.

Figure 20-2

Composite images from a cardiac CT and cardiac MRI (CMR) demonstrate small crypt-like formations involving the inferior basal wall of the left ventricle. The underlying coronary arteries are normal. There was no history of hypertrophic cardiomyopathy. Similar findings were confirmed on CMR, with no delayed enhancement. See

Myocardial Diverticulum

Congenital left ventricular (LV) diverticula are rare cardiac malformations characterized as outpouchings of the myocardium and can be fibrous or muscular. The prevalence has been reported between 0.02% and 0.04%. They are associated with other congenital abnormalities in about 70% of cases. Muscular diverticula typically are apical and have a full-thickness myocardial wall with preserved systolic contraction. Diverticula can be differentiated from crypts or clefts by a narrow mouth but a wide outpouching extending beyond the normal LV margins. Cardiac CT (CCT) has been proposed as useful for differentiating aneurysm from pseudoaneurysm by exclusion of coronary artery disease, visualization of the LV wall layers, and dynamic assessment of regional wall function ( Fig. 20-3 ).

Figure 20-3

A 29-year-old asymptomatic man was referred for treatment of Crohn’s disease. Before commencing treatment, the patient underwent cardiac assessment. A, An echocardiogram showed a localized low-echoic cavity with a discontinuity in the basal part of the left ventricular (LV) lateral wall close to the atrioventricular groove. B, Reconstructed multidetector CT clearly showed the spatial relationship between the coronary artery and the pseudoaneurysm ( arrows ). C and D, Color Doppler imaging showed bidirectional blood flow between the LV and the cavity through a narrow communication, consistent with a diagnosis of LV pseudoaneurysm. Coronary angiography showed no atherosclerotic stenosis. E and F, Remarkably, the proximal part of the left circumflex coronary artery ( arrows ) became very thin during systole due to a dyskinetic expansion of the pseudoaneurysm, indicating a myocardial bridging-like squeeze

(Reprinted with permission from Katayama T, Murata M, Iwanaga S, et al. Left ventricular pseudoaneurysm with peculiar coronary artery collapse. J Am Coll Cardiol . 2009;53(19):1823.)

Post-Infarction Ventricular Pseudoaneurysms, Septal Rupture, and Intramyocardial Hematoma

Pseudoaneurysms are an uncommon complication of acute myocardial infarction, occurring in less than 1% of cases. Cardiac surgery, penetrating or other trauma, and infection also can lead to the development of these abnormalities. The excellent spatial resolution of CT should be ideal for identifying the myocardial wall disruption. Single case reports have demonstrated the ability of CCT to depict post-infarction ventricular pseudoaneurysms, and coronary anatomy.

  • Post-infarction septal rupture and intramyocardial hematoma also have been noted in single case reports.

  • For CCT images of post-infarction pseudoaneurysms, see Figure 20-4 .

    Figure 20-4

    A, Three-dimensional volume-rendered image shows the patent left internal mammary to left anterior descending artery graft in relation to the left ventricular pseudoaneurysm (LVPA). B, Transesophageal image shows the large LVPA arising from the lateral wall below the mitral valve and reveals the abrupt myocardial discontinuity marking the neck of the LVPA. Cardiac CTA modified four-chamber ( C ), horizontal long-axis ( D ), and two-chamber ( E ) views of the heart show the posterobasal opening of the LVPA and its relation to adjacent cardiac structures.

    (Reprinted with permission from Yavari A, Sriskandan N, Khawaja MZ, et al. Computed tomography of a broken heart: chronic left ventricular pseudoaneursym. J Cardiovasc Comput Tomogr . 2008; 2:120.)

  • For CCT images of post-infarction septal rupture, see Figures 20-5 and 20-6 ;

    Figure 20-5

    A, Four-chamber view echocardiogram with a cavity by the right ventricle ( arrow ). B, Four-chamber view after intravenous contrast, showing no enhancement of the structure ( arrow ). Curved multiplanar reconstructions show that the right coronary artery ( C ) has a high-grade lesion ( arrow ) and poor contrast opacification in the distal portion of the artery, and that there is nonsignificant stenosis of the left circumflex artery ( D ) and of the left anterior descending artery ( E ). F, Short-axis view shows the ventricular septal rupture ( larger arrow ), the myocardial dissection ( two small arrows at both sides of the right ventricular wall), and the re-entry orifice on the right ventricle ( arrowhead ). G, Multiple orifices document the complex anatomy of the ventricular septal rupture.

    (Reprinted with permission from Bittencourt MS, Seltmann M, Muschiol G, Achenbach S. Ventricular septal rupture and right ventricular intramyocardial dissection secondary to acute inferior myocardial infarction . J Cardiovasc Comput Tomogr . 2010;4(5): 342-344.) See

    Figure 20-6

    ECG-gated contrast-enhanced CT images ( A and B ), steady-state free precession cardiac MR (CMR) images ( C and D ), and photo ( E ) of the surgical repair of a post-infarction septal rupture. The CT and CMR images reveal the aneurysmal deformation of the inferior septum as well as the inferior wall. The CT images in particular reveal the detail of the septal rupture (fenestrations of the thinned aneurysmal septum). The thinness of the aneurysmal inferior septum and inferior wall is most obvious on the CMR images. The surgical photo shows the thinness of the aneurysmal septum, adjacent to the pericardial patch. See

Post-Infarction Left Ventricular Aneurysm

True aneurysms of the LV most commonly are secondary to myocardial infarction but can (rarely) be congenital in origin or secondary to inflammatory (e.g., Kawasaki disease and sarcoidosis) or infectious (e.g., Chagas) disease. Occasionally changes associated with right ventricular dysplasia or hypertrophic cardiomyopathy also can be associated with LV aneurysm formation.

For CCT images of ventricular aneurysms, see Figures 20-7 through 20-10 ;

Figure 20-7

Composite image from a cardiac CT study in a 64-year-old man, previously healthy, with an episode of chest pain 6 weeks prior. Echocardiography performed on the same day, prior to the cardiac CT study, suggested a false aneurysm of the left ventricle. Multiple reformatted images of the left ventricle demonstrate a focal area of thinning and dyskinesis involving the inferolateral wall. The mouth of the aneurysm is larger than the mid-portion of the aneurysm. No evidence is seen of a pericardial effusion, or stranding of the pericardial fat. These findings all favor a true aneurysm. See

Figure 20-8

Evaluation of the left ventricle in the same patient as in Figure 20-7 demonstrates reduced left ventricular ejection fraction of 32%. A moderate area of laminated thrombus is noted adjacent to the septum in the mid- to distal portion of the left ventricle. Delayed imaging demonstrates an underlying region of delayed enhancement consistent with prior infarction in this area.

Figure 20-9

A and B, Volume-rendered representations of the entire ventricular volume. The study was acquired in a dose-modulated healed helical fashion. A, End diastole; B, end systole. These images demonstrate akinesis of the distal portion of the left ventricle consistent with a myocardial infarction in the left anterior descending artery (LAD) area. Functional analysis generates an indexed end-diastolic volume of 129 mL/m 2 , moderately dilated. There is mild reduction in overall ejection fraction with a left ventricular ejection fraction of 46%. C, Precontrast calcium score study demonstrates a small amount of fatty metaplasia within the distal septum. D, The companion post-contrast image demonstrates focal thinning of the distal septum extending into the apex. Curved multiplanar reformations ( E ) and maximum intensity projection (MIP) ( F ) images through the left anterior descending coronary artery demonstrate moderate to severe disease within the proximal to mid-LAD. A 70% proximal LAD lesion consisting of mixed plaque is present. There has been prior stenting of a mid-LAD lesion (best seen on A) . No evidence of in-stent restenosis is seen.

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Apr 10, 2019 | Posted by in COMPUTERIZED TOMOGRAPHY | Comments Off on Assessment of Left Ventricular Structural Abnormalities

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