Letter from the Editors: Planar Imaging in the Age of SPECT
Article Outline
We live in an age of high technology with incredible advances almost every day. The computer and the smart phone have become essentials of daily life. Very few people hold on to these devices for more than a few years, replacing them with rapidly advancing new technology. In many ways this has been true of nuclear medicine. The introduction of single-photon emission computed tomography (SPECT) has led to its wide acceptance. Most general diagnostic imaging procedures are done now with SPECT imaging devices. More recently, the addition of computed tomography (CT) to SPECT provides the capability of performing attenuation correction using the CT part of the device, and fusion imaging for the increased specificity and correlative benefits that they offer. Does this technological advance mean that planar imaging is obsolete and no longer plays an important role in diagnostic nuclear medicine? Nothing could be further from the truth. In this issue, we present a series of articles devoted to planar scintigraphy highlighting those areas where planar imaging remains a vital part of the overall nuclear medicine diagnostic process. In some situations, SPECT also can be done for the same indication, but there may not be a significant improvement in diagnostic accuracy and specificity by moving from the simple inexpensive planar device to the more sophisticated SPECT device.
We lead off this issue with an article by one of the editors, Dr. Leonard M. Freeman,1 on a subject to which he has devoted a major amount of his time during the last several years. Dr. Freeman and his coauthors clarify for us the role of ventilation/perfusion (V/Q) imaging in the diagnosis of pulmonary embolism (PE) and its efficacy in diagnosing that disorder. They also discuss the role of SPECT in V/Q imaging, an area that has provoked considerable controversy. The overall conclusion is that planar V/Q imaging is quite adequate in its ability to detect clinically significant PE.
The radionuclide bone scan is an area where planar imaging continues to flourish as it does in the other subjects chosen for this issue. Although it is possible that there is improved diagnostic capability using SPECT/CT for bone imaging, it remains to be shown whether or not planar imaging should be abandoned for this newer modality. Dr. Arnold Brenner and coworkers clarify for us the broad role and impressive diagnostic contribution of planar scintigraphy in bone imaging.2
Another area where planar imaging continues to play a dominant role is in the evaluation of brain death. Drs. Partha Sinha and G.R. Conrad3 point out that because of the difficulties in imaging a patient in the precarious state of suspected brain death, planar imaging continues to have a dominant role. Some consideration may need to be given to SPECT imaging as well, although it presents logistic difficulties in its performance. Drs. Sinha and Conrad review for us the relative roles of these two modalities.
Yet another area where planar imaging dominates our practice, and SPECT imaging serves as a secondary rather than primary modality, is in liver and hepatobiliary imaging. Drs. Michael Middleton and Mark Strober review for us the use of planar imaging in this situation.4
One of the areas where SPECT imaging has impacted negligibly on nuclear medicine practice is in renal nuclear medicine. Although renal nuclear medicine includes areas such as renal infection, where SPECT imaging can be quite valuable, the day-to-day performance of diuresis renography and other types of renography are best done with conventional planar imaging. Although we use the word conventional, in reality there are many complexities in performing renal imaging and reporting the results. Dr. Andrew Taylor and a group of coauthors chosen from around the world provide us with a document for guidance in reporting of diuresis renography in adults.5 Uniformity of reporting procedures and guidance documents like these are very helpful, particularly in an area that is encumbered by as many differing and often conflicting approaches as renal nuclear medicine.
Thyroid imaging in both benign and malignant disease remains the province primarily of planar imaging, with SPECT playing an ancillary role. Dr. Charles Intenzo and his coauthors provide a very authoritative and controversial view of the role of thyroid imaging in benign and malignant disease, emphasizing the use of planar scintigraphy.6
Finally, Dr. Lionel Zuckier has written an article on technical innovations in planar scintigraphy.7 Here Dr. Zuckier reviews for us efforts to provide anatomic information with planar imaging. As he points out, although SPECT appeared on the scene, and much later SPECT/CT was introduced for anatomic localization, the truth is that planar scintigraphy was utilized along with devices that provided anatomic information many years before SPECT was even invented. His review is an interesting one, pointing out that recognition of the value of anatomic imaging combined with functional imaging is an old concept that was embraced by the pioneers in nuclear medicine.
This issue reviews for us a modality that continues to play an important role in our daily practice. Planar imaging is still with us and there is no need to discard these machines that we have relied on for all of these years. Although it is likely that SPECT/CT and PET/CT, will eventually replace it, there is still a need for planar imaging at this time. Even their future is threatened with the recent introduction of PET/MRI and numerous other modalities that are in development and in early stages of introduction to the clinical community, such as the dedicated cameras that were reviewed in the May issue of the Seminars in Nuclear Medicine.8
One final note is worth commenting on. In the May issue of the Seminars, the Editors purposefully chose to use articles submitted only by members of the faculty of the Department of Nuclear Medicine of the Albert Einstein College of Medicine and Montefiore Medical Center. This was the first time we have ever done that in all the years of publishing Seminars, during which time we kept a promise to keep the authorship as broad and diversified as possible. This issue represents another departure from our effort to choose authors only from other institutions. Without purposefully thinking about it, we find ourselves with the majority of the articles published by former residents of the Department of Nuclear Medicine. Dr. Freeman's article includes a current resident. Drs. Arnold Brenner, Partha Sinha, Michael Middleton, Mark Strober, and Lionel Zuckier were all residents here at the Albert Einstein College of Medicine and Montefiore Medical Center. Even the article by Dr. Taylor includes a contribution from an Einstein faculty member (M. Donald Blaufox). The single exception is the thyroid article by Dr. Charles Intenzo et al. We are both proud and delighted that a major part of a single issue of the Seminars in Nuclear Medicine could be written by individuals who have trained with us and have achieved a prominent role in the field of Nuclear Medicine.
References
- . Planar V/Q imaging for pulmonary embolism: the case for “outcomes” medicine. Semin Nucl Med. 2012;42:3–10
- The bone scan. Semin Nucl Med. 2012;42:11–26
- . Scintigraphic confirmation of brain death. Semin Nucl Med. 2012;42:27–32
- . Planar scintigraphic imaging of the gastrointestinal tract in clinical practice. Semin Nucl Med. 2012;42:33–40
- Guidance document for structured reporting of diuresis renography. Semin Nucl Med. 2012;42:41–48
- Imaging of the thyroid in benign and malignant disease. Semin Nucl Med. 2012;42:49–61
- . Hybrid imaging in planar scintigraphy: new implementations, historical persepectives. Semin Nucl Med. 2012;42:62–72
- . Dedicated Imaging Devices. Semin Nucl Med. 2011;41:149–242
PII: S0001-2998(11)00125-5
doi:10.1053/j.semnuclmed.2011.08.002
© 2012 Elsevier Inc. All rights reserved.
