Abnormal photopenic area on nuclear perfusion imaging

NUCLEAR CARDIOLOGY BULLET Abnormal photopenic area on nuclear perfusion imaging Muhammad Raza, MD,a Mrinalini Meesala, MD,a Gurusher Panjrath, MD,b Afshin Ghanbarinia,b and Diwakar Jain, MDb Case history. A 75-year-old African American man with a prior history of hypertension, hyperlipidemia, and stroke presented to the hospital with abdominal discomfort and dizziness. He also complained of severe constipation for 13 days before admission. A physical examination revealed a mildly distended abdomen, which was attributed to fecal impaction from constipation. An electrocardiogram was significant for bradycardia with first-degree heart block and frequent premature ventricular complexes. The abdominal obstruction series showed distended bowel loops consistent with severe constipation (Figure 1A and B). Because of risk factors for coronary artery disease, the patient was referred for a myocardial perfusion imaging study. A symptom-limited treadmill exercise test was attempted. However, he was unable to walk for more than 5 minutes on the modified Bruce protocol and did not attain the target heart rate; therefore the test was changed to pharmacologic stress testing via a 5-minute adenosine infusion protocol. With adenosine infusion, the heart rate changed from 75 to 87 beats/min and blood pressure remained unchanged at 160/70 mm Hg. The patient complained of chest tightness. A baseline electrocardiogram showed frequent ventricular ectopic beats at rest, which persisted during adenosine infusion, but there was no ST-segment depression. Technetium 99m sestamibi (Cardiolite; Bristol-Myers Squibb, Princeton, NJ), 25 mCi, was injected during adenosine infusion, and gated single photon emission computed tomography (SPECT) images were acquired 45 minutes later. Rest images were acquired the next day with same dose of Tc-99m sestamibi. Gated SPECT images revealed an enlarged, hypertrophied, and hypokinetic left ventricle with an ejection fraction of 34% (Figure 2). However, there was no regional perfusion abnormality. From the Department of Internal Medicine,a and Division of Nuclear Cardiology,b Drexel University College of Medicine, Philadelphia, Pa. Reprint requests: Diwakar Jain, MD, Professor of Medicine, Director of Nuclear Cardiology, Drexel University College of Medicine, 245 N 15th St, MS 470, Philadelphia, PA, 19102; Diwakar.Jain@drexel.edu. J Nucl Cardiol 2005;12:607-9. 1071-3581/$30.00 Copyright © 2005 by the American Society of Nuclear Cardiology. doi:10.1016/j.nuclcard.2005.05.012 The result was consistent with hypertensive heart disease. Incidentally, there was a large oval photopenic area noticed in the left side of the abdomen suspicious of a large fluid-filled structure or mass (Figure 3). These findings resulted in a series of radiologic investigations to determine the nature of the lesion. A computed tomography scan of the abdomen revealed a large (16 ⫻ 14 ⫻ 17 cm) fluid-filled structure near the lower pole of the left kidney (Figure 4A and B). There were several adjacent smaller renal cysts on the same side and many hypoattenuating rounded lesions in the contralateral kidney. These findings raised the suspicion of adult polycystic kidney disease. Magnetic resonance imaging of the abdomen was performed, which revealed a 14 ⫻ 15 ⫻ 17– cm mass in the lower pole of the left kidney with a 3-mm enhancing wall and a 1.0 ⫻ 1.4 – cm lesion in the lateral segment of the left lobe of the liver (Figure 5A, B, and C). In addition, there were multiple other simple cysts in the left kidney, the largest one measuring 3.5 cm in diameter in the upper pole. There was a 1.2-cm lesion in the upper pole of the right kidney consistent with a hemorrhagic cyst. The large left renal lesion was classified as Bosniak 3, which pertains to indeterminate cystic masses that need surgical evaluation or removal, although many Figure 1. Obstruction series (erect [A] and supine [B]) shows gas-filled loops of proximal large bowel (arrows) but no evidence of dilatation or obstruction. Arrowhead, Air-fluid level in stomach. 607 608 Raza et al Abnormal photopenic area on nuclear perfusion imaging Journal of Nuclear Cardiology September/October 2005 Figure 2. Resting short-axis vertical and horizontal long-axis slices showing no regional perfusion abnormality. Gated images showed a left ventricular ejection fraction of 34%. Figure 3. Representative frames of raw rotating images show large oval photopenic area (arrows) in left side of abdomen suspicious of large fluid-filled structure. prove to be benign.1 These findings were discussed with the patient, who declined to undergo surgery. Discussion. Myocardial perfusion imaging is commonly used for the detection of coronary artery disease and the assessment of left and right ventricular function. The raw projection images are helpful in the identification of attenuation and motion artifacts, and they can also provide important clues to the presence of incidental and significant noncardiac abnormalities.2-5 Whereas abnormal radiotracer uptake in tumors of the lung, breast, and mediastinum is well described, detection of abdominal abnormalities is relatively less common. We hereby report an unusual case of a large renal cyst that was detected as an incidental finding on myocardial perfusion imaging. Further workup revealed multiple cysts affecting the kidneys and one cyst in the liver. This was attributed to adult polycystic kidney disease with preserved renal function.6 This case emphasizes the importance of Figure 4. Computed tomography scan of abdomen (A and B) and pelvis demonstrates left renal cyst (arrows) extending from lower pole measuring about 15.6 ⫻ 13.6 ⫻ 17.1 cm. A, Aorta; K, kidney. Journal of Nuclear Cardiology Volume 12, Number 5;607-9 Raza et al Abnormal photopenic area on nuclear perfusion imaging 609 Figure 5. Magnetic resonance image of abdomen (A, B, and C) shows large mass in lower pole of left kidney measuring about 14 ⫻ 15 ⫻ 17 cm. K, Kidney. careful examination of the raw rotating images for the presence of incidental noncardiac findings. Acknowledgment The authors have indicated they have no financial conflicts of interest. References 1. Glassberg KI, Renal dysgenesis and cystic disease of the kidney. In: Walsh PC, Retic AB, Vaughan ED Jr, Wein AJ, Kavoussi LR, Novick AC, et al. editors. Campbell’s urology. Philadelphia: Saunders; 2002. p. 1925-94. 2. Williams KA, Hill KA, Sheridan CM. Noncardiac findings on dual-isotope myocardial perfusion SPECT. J Nucl Cardiol 2003;10: 395-402. 3. Hendel RC, Gibbons RJ, Bateman TM. Use of rotating (cine) planar images in the interpretation of a tomographic myocardial perfusion study. J Nucl Cardiol 1999;6:234-40. 4. Panjrath GS, Narra K, Jain D. Myocardial perfusion imaging in a patient with chest pain. J Nucl Cardiol 2004;11:515-7. 5. Raza M, Panjrath G, Jain D. Unusual retrocardiac radiotracer uptake on sestamibi perfusion images. J Nucl Cardiol 2004;11: e1-2. 6. Fick-Brosnahan GM, Ecder T, Schrier RW. Polycystic kidney disease. In: Schrier RW, editor. Diseases of the kidney and urinary tract. Philadelphia: Lippincott Williams & Wilkins; 2001. p. 547-88.