DOI:10.2214/AJR.07.2980
AJR 2008; 190:W169
© American Roentgen Ray Society
A More Detailed View Calls for More Detailed Definition: Description of Cardiac Morphology with High-Resolution CT and MRI
Tjeerd Germans,
Robin Nijveldt and
Albert C. van Rossum
VU University Medical Center Amsterdam, The Netherlands Interuniversity
Cardiology Institute of The Netherlands Utrecht, The Netherlands
WEB—This is a Web exclusive article. T. Germans was supported
by grant 2006B213 and R. Nijveldt was supported by grant 2003B126 from The
Netherlands Heart Foundation.
High-resolution imaging techniques such as CT and MRI have significantly
improved the noninvasive diagnostic accuracy in coronary artery disease and
provide more detailed tissue characterization in ischemic and nonischemic
cardiomyopathies. These techniques facilitate research focused on a more
accurate description of cardiac morphologic abnormalities that are difficult
to observe with echocardiography, as recently reported by Srichai and
coworkers [1]. In that study,
contrast-enhanced gated cardiac CT was used to describe the prevalence and
morphology of cardiac diverticula. The authors found that cardiac diverticula
were prevalent in 2.2% of a referral-based population and were related to
various cardiomyopathies. In addition, they observed that cardiac diverticula
were predominantly located in the inferior and inferoseptal segments of the
left ventricle.
The muscular form of cardiac diverticula shown in Figure 4 of the Srichai
et al. [1] article, strongly
resembles the morphology of the crypts that we
[2] recently described to be
present in the majority (81%) of hypertrophic cardiomyopathy mutation carriers
and that probably precede the development of left ventricular hypertrophy. We
think that "crypts" was a more accurate term to describe this
structural abnormality because the term diverticula suggests bulging out of a
hollow organ rather than penetration into the muscular wall. We hypothesize
that this penetration of compact myocardium may represent either myocyte
disarray, which is in line with the exceptionally high prevalence of crypts in
hypertrophic cardiomyopathy mutation carriers and the preferential location at
the insertion points of the right ventricle into the left ventricle, or
cleavage of the laminar myocardial sheets due to locally altered loading
conditions or myocardial contractility.
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Fig. 1A —Distinguishing crypts from noncompaction cardiomyopathy. LA =
left atrium, LV = left ventricle, RV = right ventricle. Cardiac MR
steady-state free precession cine images of 22-year-old woman who is
hypertrophic cardiomyopathy mutation carrier (A) and 36-year-old man
with noncompaction cardiomyopathy (B). Note that crypts, located in
basal inferoseptum (arrowheads, A) penetrate compact
myocardium whereas in noncompaction cardiomyopathy, broad noncompacted layer
of myocardium (asterisk, B) aligns with compact layer of
myocardium and is predominantly located in apex or lateral segments of left
ventricular wall.
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Fig. 1B —Distinguishing crypts from noncompaction cardiomyopathy. LA =
left atrium, LV = left ventricle, RV = right ventricle. Cardiac MR
steady-state free precession cine images of 22-year-old woman who is
hypertrophic cardiomyopathy mutation carrier (A) and 36-year-old man
with noncompaction cardiomyopathy (B). Note that crypts, located in
basal inferoseptum (arrowheads, A) penetrate compact
myocardium whereas in noncompaction cardiomyopathy, broad noncompacted layer
of myocardium (asterisk, B) aligns with compact layer of
myocardium and is predominantly located in apex or lateral segments of left
ventricular wall.
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Although this entity has been previously described as a form of
noncompaction cardiomyopathy, a cardiomyopathy suggested by the authors
[1] to be considered in the
differential diagnosis of the crypts, we would like to emphasize that it is
important to discriminate crypts from noncompaction cardiomyopathy because the
clinical course of patients in whom the crypts are observed (i.e.,
hypertrophic cardiomyopathy mutation carriers) may significantly differ from
patients with noncompaction cardiomyopathy
[3–5].
Indeed, discrimination between these two cardiomyopathies remains challenging
with echocardiography but can readily be made with cardiac MRI or CT using the
following criteria: crypts penetrate compact myocardium whereas in
noncompaction cardiomyopathy, a broad noncompacted layer aligns with a compact
layer of myocardium; crypts are mainly located in the mid and basal
inferoseptal segments of the left ventricle whereas noncompaction mainly
occurs in the apical and lateral segments (Fig.
1A,
1B); and, in contrast to
noncompaction cardiomyopathy, crypts are not associated with a reduced left
ventricular ejection fraction
[4].
State-of-the-art imaging techniques allow better description and
understanding of cardiac morphology but consequently require a strict
definition of the newly acquired observations. As a result, our improved
knowledge of cardiomyopathies may lead to further refinement of the diagnosis
and to subsequent optimization of therapy.
References
- Srichai MB, Hecht EM, Kim DC, Jacobs JE. Ventricular diverticula on
cardiac CT: more common than previously thought. AJR2007; 189:204
–208[Abstract/Free Full Text]
- Germans T, Wilde AA, Dijkmans PA, et al. Structural abnormalities
of the inferoseptal left ventricular wall detected by cardiac MRI in carriers
of hypertrophic cardiomyopathy mutations. J Am Coll
Cardiol 2006; 48:2518
–2523[Abstract/Free Full Text]
- McCrohon JA, Richmond DR, Pennell DJ, Mohiaddin RH. Images in
cardiovascular medicine: isolated noncompaction of the myocardium—a
rarity or missed diagnosis? Circulation2002; 106:e22
–e23[Medline]
- Germans T, Dijkmans PA, Wilde AA, Kamp O, van Rossum AC. Images in
cardiovascular medicine: prominent crypt formation in the inferoseptum of a
hypertrophic cardiomyopathy mutation carrier mimics noncompaction
cardiomyopathy. Circulation 2007;115
:e610
–e611[Free Full Text]
- Stollberger C, Finsterer J. Left ventricular
hyper-trabeculation/noncompaction and stroke or embolism.
Cardiology 2005;103
: 68–72[CrossRef][Medline]
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