# Cardiac Nuclear Imaging Findings in Atypical Variants of Takotsubo Cardiomyopathy
## 3 Results
### Analysis of the Evidence
#### 3.3.1 Cardiac Nuclear Imaging Findings in Midventricular TTC  
In 2008, [PERSON] and colleagues [72], analyzed imaging patterns obtained with 99 mTc-tetrofosmin gated-single photon emission computed tomography (G-SPECT), 123I-mIBG SPECT, and 18F-FDG gated-positron emission tomography (G-PET) of an 83-year-old  
Figure 2: CASP diagnostic checklist: tabular representation of quality assessment results [70; 71; 75]. woman with typical TTC and a 67-year-old woman with transient midventricular ballooning. In the patient with the atypical variant of TTC, despite the myocardial perfusion images revealing no defects, the analysis of the left ventricular motion and thickness showed severe midventricular hypokinesia associated with a decreased left ventricular ejection fraction (LVEF) measured by G-SPECT. Moreover, the authors revealed a similar pattern of 123I-mIBG and 18F-FDG uptake, with defects related to left ventricular dysfunction. Following this case report, a retrospective study involving a total of 18 patients, of whom 5 subjects had midventricular TTC, was published in 2009 [71]. Myocardial perfusion imaging with 99 mTc-tetrofosmin or 201-Tl was performed on three out of five subjects in the sub-acute phase and revealed the absence of perfusion defects, associated with a severe midventricular hypokinesi with preserved apical and basal function. 123I-mIBG SPECT and 18F-FDG G-PET were performed in one and in all five patients, respectively. Hypocontractile but normally perfused segments were characterized by a severe decrease in both 123I-mIBG and 18F-FDG uptake, with a large topographic overlapping of the metabolic defects and innervation abnormalities on the qualitative analysis. Previously, in 2007, [PERSON] and coworkers [70] retrospectively analyzed 35 patients with TLVDS, of whom 13 had atypical midventricular TTC. The myocardial perfusion 99 mTc-sestamibi scintigraphy and 18F-FDG PET studies showed a strong correlation between the location of the wall motion abnormality and myocardial perfusion/metabolism defects. In particular, myocardial glucose metabolism was revealed to be affected to a greater extent than perfusion, leading to an inverse mismatch typical for the appearance of postischemic stunned myocardium. A case of transient midventricular akinesia in a 67-year-old woman without a history of heart disease was reported in 2008 by [PERSON] et al. [77]. During the acute phase, decreased uptake was seen in the 123I-BMIPP myocardial scintigraphy. The main finding in the acute phase was the discrepancy of the uptake between the mid region and apex, which reduced during the course. On the other hand, the decreased uptake revealed on the 123I-mIBG scintigraphy in the mid portion during the acute phase persisted through 3 and 6 months later. Similarly, the washout map showed an increased washout in the mid to basal portion of the inferior and lateral wall during the acute phase and increased the washout in the mid portion of the anterolateral wall in images taken 3 and 6 months later, suggesting how the abnormal findings of the 123I-mIBG persisted for 6 months even though the left ventricle contraction was recovered. The above-described findings concerning 123I-BMIPP scintigraphy are in line with a previous case report of a 51-year-old Japanese man published in 2007 by [PERSON] and colleagues [78], who revealed a decreased uptake in the mid ventricle corresponding to the midventricular akinetic region, which normalized at 4 months after discharge. 99 mTc-sestamibi scintigraphy, also performed by the authors on the fifth day, showed no perfusion defects. Similarly, normal 201 Tl uptake was revealed on early images performed on the third day of admission in an 87-year-old woman diagnosed with a midventricular variant of TTC, as reported by [PERSON] and coworkers [79] a year later.