case_images: PMC6131291_01
case_images: Coronary angiography at the (a) left anterior oblique artery (40 ) revealing
  tight stenosis with severe calcification at the mid-RCA (arrow) and (b)
  right anterior oblique artery (30 ) revealing tight stenosis with severe
  calcification at the mid-RCA (arrow). (c) OFDI demonstrated the presence of
  irregular surfaced protruding masses with signal attenuation (arrows). (d)
  IVUS demonstrated the presence of protruding masses with superficial
  hyperechoic signal accompanied by acoustic shadowing (arrows).
case_images: 10.1177_2050313X18799243-fig1.jpg
case_images: PMC6131291_01_10.1177_2050313X18799243-fig1.jpg
case_images: fig1-2050313X18799243
case_images: Coronary angiography revealed tight stenosis with severe calcification at the mid part of the right coronary artery (Figure 1(a) and (b)). Optical frequency domain imaging (OFDI; Lunawave; Terumo Corporation, Tokyo, Japan) indicated the presence of a high-backscattering protruding mass with an irregular luminal surface and signal attenuation (Figure 1(c)). Meanwhile, intravascular ultrasound (IVUS; Atlantis; Boston Scientific Corporation, Natick, MA, USA) indicated the appearance of a protruding mass with a superficial hyperechoic signal accompanied by acoustic shadowing (Figure 1(d)).
case_images: (a) RA with a 2.0 mm burr. (b) Coronary angiography after the RA with a
  2.0 mm burr. CN persisted, as indicated by coronary angiography (arrow). (c)
  OFDI indicated an increase in the lumen area. CN was well ablated by RA with
  a 2.0 mm burr (arrows).
case_images: 10.1177_2050313X18799243-fig2.jpg
case_images: PMC6131291_01_10.1177_2050313X18799243-fig2.jpg
case_images: fig2-2050313X18799243
case_images: We performed lesion modification by RA with a 2.0 mm burr after implantation of temporary pacing (Figure 2(a)). After RA, although coronary angiography revealed no change, OFDI showed an increase in the minimum lumen area by ablation of the CN by RA (Figure 2(b) and (c)).
case_images: (a) RA with a 2.25 mm burr. (b) CN disappeared after RA with a 2.25 mm burr
  by coronary angiography (arrow). (c) OFDI indicated a much larger lumen area
  compared to the burr size for RA.
case_images: 10.1177_2050313X18799243-fig3.jpg
case_images: PMC6131291_01_10.1177_2050313X18799243-fig3.jpg
case_images: fig3-2050313X18799243
case_images: Therefore, we performed additional RA with a larger burr size (2.25 mm) (Figure 3(a)). After RA, the CN was found to have disappeared on coronary angiography (Figure 3(b)), and OFDI showed lumen area that was larger than expected area by the burr size of RA (Figure 3(c)).
case_images: (a) Coronary angiography indicated embolization of CN at the distal part of
  the RCA (arrow). (b) IVUS revealed an embolus with some calcification in a
  healthy small vessel. (c) Balloon angioplasty with a 2.0 mm balloon was
  performed. (d) Stenosis persisted after balloon angioplasty, as indicated by
  coronary angiography (arrow). (e) Coronary angiography showed no residual
  stenosis after stenting with a 2.25 mm stent. (f) IVUS after stenting
  revealed sufficient circle stent expansion.
case_images: 10.1177_2050313X18799243-fig4.jpg
case_images: PMC6131291_01_10.1177_2050313X18799243-fig4.jpg
case_images: fig4-2050313X18799243
case_images: However, distal embolization of the ablated nodule occurred, and the patient developed chest pain with slight ST elevation on the inferior leads (Figure 4(a)). We performed IVUS and identified loose clots containing some calcification (Figure 4(b)). Yet, coronary angiography after balloon dilation revealed recoil of the lesion (Figure 4(c) and (d)). We implanted a 2.25-mm drug-eluting stent and achieved good stent expansion (Figure 4(e)). After stenting, IVUS showed full stent expansion and a compressed embolus outside the stent (Figure 4(f)).
case_images: (a) Final coronary angiography revealed good results. (b) Final OFDI
  demonstrated good stent expansion and compressed CN outside the stent
  (arrows).
case_images: 10.1177_2050313X18799243-fig5.jpg
case_images: PMC6131291_01_10.1177_2050313X18799243-fig5.jpg
case_images: fig5-2050313X18799243
case_images: Final coronary angiography revealed a good result without any distal embolization and OFDI revealed good stent expansion of the lesion with CN (Figure 5(a) and (b)).