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October 2022, Volume 72, Issue 10


Accentuated 123ImIBG uptake by the left lobe of the liver — A clue to nowhere

Humayun Bashir  ( Department of Nuclear Medicine, )
Carolina Pina  ( Department of Nuclear Medicine, )
Liviu Stanisor  ( Department of Nuclear Medicine, )
Kashif Naeem  ( Department of Radiology, East Kent Hospitals University Foundation NHS Trust, Canterbury, United Kingdom, )


A 57-year-old male was imaged with 123I mIBG for left sided suprarenal mass. The planar and SPECT-CT acquisitions revealed features consistent with a left sided pheochromocytoma. There was physiological and high uptake in the hypertrophied left lobe of the liver which was normal at both MRI and non-contrast CT. Asymmetrical increased 123I mIBG uptake in the left lobe of the liver as compared to the right lobe is a known physiological finding with no obvious cause or significance.


Keywords: mIBG, left lobe of liver, phylogenetic inheritance, pheochromocytoma, SPECT/CT.




A 57-year-old gentleman was referred for an 123I mIBG (radioiodine-123 Meta-Iodo-Benzyl-Guanidine) whole body study with history of hypertension, raised catecholamines and metanephrines. The purpose of the mIBG study was to rule out metastatic spread from the highly suspected pheochromocytoma, which can be seen in 10-15% of the cases.1,2

Patient was injected with 123I mIBG followed by whole body planar study at 6 and 24 hours (Image-1). SPECT/CT of the abdomen was acquired at 6 hours (Image-2).

mIBG study showed intense homogeneous 123I mIBG uptake in the left supra-renal 49 mm lesion, along with physiological homogeneous high uptake in the otherwise normal appearing left lobe of the liver. Physiological 123I mIBG uptake was also demonstrated in the salivary glands, myocardium, thyroid, liver, spleen, and the lungs, as well as excretion in the urinary bladder. A subsequent MRI study for the adrenals also showed features highly suggestive of a 49 mm left sided pheochromocytoma with normal left lobe of the liver.

Hypertrophy of the left lobe of the liver (Netter’s Type 4) with a normal functional right lobe of the liver is a known entity.3 Asymmetrical increased uptake of mIBG in the left lobe of the liver is also known and a very intriguing entity with no established cause.4 Jacobsson et al5 established a ‘flip-flop phenomenon’ by comparing the hepatic distribution of 4 radiopharmaceuticals. While the uptake of 111In-pentetreotide and 99mTc HIDA was higher in the right lobe, 99mTc-labelled monoclonal antibodies directed against human granulocytes (mAb) showed equal distribution between the right and the left lobe. 123ImIBG uptake was always found higher in the left lobe.

The preferential accumulation of mIBG in the left lobe is related to sympathetic receptors and unrelated to iodine as it is not noted on radioiodine scans (I123 NaI or I 131 NaI) in thyroid cancer patients. One proposed explanation of the higher uptake of [123I]-mIBG by the left lobe may be a greater presence of catecholamines and a higher sympathetic nerve density in this liver portion,5 the significance of which is not yet established. Jo HS et al. found no difference in outcome of right vs left hepatectomy performed for the treatment of hilar cholangiocarcinoma.[6 Jacobsson et al. are inclined to subscribe to ‘phylogenetic inheritance,’ of Rex H from 1888 in which he had suggested a functional difference between the two main liver lobes as a reflection in their timing of origins in the evolution.7 For now the mystery continues to intrigue and should be known to clinicians and technologists involved in imaging and therapy with mIBG.8




1.      Granberg D, Juhlin CC, Falhammar H. Metastatic Pheochromocytomas and Abdominal Paragangliomas. J Clin Endocrinol Metab. 2021; 106:e1937-e1952. doi: 10.1210/clinem/dgaa982. PMID: 33462603; PMCID: PMC8063253.

2.      Sharp SE, Trout AT, Weiss BD, Gelfand MJ. MIBG in Neuroblastoma Diagnostic Imaging and Therapy. Radiographics. 2016; 36:258-78. doi: 10.1148/rg.2016150099. PMID: 26761540.

3.      Joshi SS, Reddy N, Joshi SD, Mittal P. Morphological variations of left lobe of liver. Int J Contemp Med Res 2017; 4:1956-1958.l

4.      Bonacina M, Albano D, Steimberg N, Bosio G, Camoni L, Bertagna F, Different uptake of 123I-MIBG in the two main liver lobes: A persistant unsolved mistery. Rev Esp Med Nucl Imagen Mol (Engl Ed). 2018;37:285-289. English, Spanish. doi: 10.1016/j.remn.2018.01.004. Epub 2018 May 10. PMID: 29754941.

5.      Jacobsson, H., Jonas, E., Hellström, P. et al. Different concentrations of various radiopharmaceuticals in the two main liver lobes: a preliminary study in clinical patients. J Gastroenterol. 2005; 40:733–738 .

6.      Jo HS, Kim DS, Yu YD, Kang WH, Yoon KC. Right-side versus left-side hepatectomy for the treatment of hilar cholangiocarcinoma: a comparative study. World J Surg Oncol. 2020; 18:3. doi: 10.1186/s12957-019-1779-1. PMID: 31901228; PMCID: PMC6942359.

7.      Rex H. Contributions to the morphology of the mammalian liver (in German). Morphol Year b 1888;14:517-617.

8.      Huang SY, Bolch WE, Lee C, Van Brocklin HF, Pampaloni MH, Hawkins RA, Patient-specific dosimetry using pretherapy [¹²⁴I]m-iodobenzylguanidine ([¹²⁴I]mIBG) dynamic PET/CT imaging before [¹³¹I]mIBG targeted radionuclide therapy for neuroblastoma. Mol Imaging Biol. 2015; 17:284-94. doi: 10.1007/s11307-014-0783-7. PMID: 25145966; PMCID: PMC4336853.

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