CERVICAL VENOUS REFLUX*

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JUNE, 1975 CERVICAL VENOUS REFLUX* A NORMAL VARIANT ON RADIONUCLIDE CEREBRAL BLOOD FLOW STUDY IN NUCLEAR MEDICINE ADIONUCLIDE cerebral blood flow studies are performed by injecting a bolus of

bolus into the vessels of the neck and head.4 After injection, the bolus normally progresses from the arm towards the heart and then into the arteries of the neck.

1 JUNE, 1975 CERVICAL VENOUS REFLUX* A NORMAL VARIANT ON RADIONUCLIDE CEREBRAL BLOOD FLOW STUDY IN NUCLEAR MEDICINE ADIONUCLIDE cerebral blood flow studies are performed by injecting a bolus of radiopharmaceutical into an antecubital vein of a patient whose head and neck are set up in front of the stationary detector of a gamma camera and by following the chronologic progression of the bolus into the vessels of the neck and head.4 After injection, the bolus normally progresses from the arm towards the heart and then into the arteries of the neck. On rare occasions, however, the radiopharmaceutical coming from the arm is seen accumulating up into the neck and sometimes higher up into the head before following through to the heart. This unusual early pattern occurring during the initial phase of the radionuclide cerebral blood flow study is considered a cervical venous reflux. It is a rare phenomenon. It has been observed in patients sitting, as well as in patients lying during their cerebral flow study and with normal as well as abnormal blood flow results. On control studies, it behaved inconsistently. In this article, the cervical venous reflux is illustrated. It is also differentiated from other patterns occurring during the initial phase of the radionuclide cerebral blood flow study. All studies presented in this article were performed with TcS9m pertechnetate as the radiopharmaceutical. MATERIAL AND METHOD The radionuclide cerebral blood flow study, as routinely performed in this laboratory, has been described elsewhere in extenso.4 The technique is summarized here and the data pertinent to this presentation are stressed. By JACQUES LAMOUREUX, M.D., PH.D. MONTREAL, QUEBEC, CANADA A Nuclear Chicago Pho Gamma scintillation camera equipped with a 4,000 hole collimator was used. The patient is facing the instrument when an anterior view flow study is obtained. The patient is turned around and the back of his head is leaning against the collimator when a posterior flow study is performed. A rubber band is wrapped around the arm maintained outside the field-of-vision ofthe collimator and 15 milhicuries of radiopertechnetate, contained in less than 2 ml. of normal saline, is injected into an antecubital vein. After the injection, the rubber band is briskly ripped off, and sequential 3 second exposures of the circulation of the radiopharmaceutical are recorded on Polaroid Paper-Film for I 6 consecutive frames. Concomitantly, 2 consecutive 20 second exposure roentgenograms are recorded. At the end of the flow study, intensity knobs on the oscilloscopes are lowered to scanning level and early scanning is performed. The patient is asked to return 3 hours later for delayed scanning. When Tc99m flow studies must be repeated, a 24 hour interval at least is maintained between studies. In this manner base-line conditions for flow studies are obtained on repeated studies. Intravenous radionuclide cerebral flow studies performed in this manner yield in sequence data: (a) about the transit of the bolus from the site of injection into the arm to the arteries in the neck (Peripheral Inflow Phase); (b) about the first passage of the bolus in the arteries of the neck and in the head (First Circulation Phase); and (c) about the manner in which the equilibrium of concentration in the various areas of the head is achieved with the * From the Division of Nuclear Medicine, Notre-Dame Hospital and Montreal University, School of Medicine. 276

VOL. i, No. 2 Cervical Venous Reflux 277 passage of time and the recirculation of the radiopharmaceutical (Recirculation Phase).

It has been shown that when a rapid intravenous bolus of radioactivity is injected into an antecubital vein, the radiopharmaceutical content in the cranium begins to rise 7 to 10 seconds after the

In using 3 second integration frames on our Polaroid Film, and starting the study at the time of injection, the first 2 or 3 frames occur during the transit time of the bolus from the vein in the arm

2 VOL. i, No. 2 Cervical Venous Reflux 277 passage of time and the recirculation of the radiopharmaceutical (Recirculation Phase). The rationale for choosing 3 second integration frames in our cerebral blood flow studies is summarized. It has been shown that when a rapid intravenous bolus of radioactivity is injected into an antecubital vein, the radiopharmaceutical content in the cranium begins to rise 7 to 10 seconds after the injection. In using 3 second integration frames on our Polaroid Film, and starting the study at the time of injection, the first 2 or 3 frames occur during the transit time of the bolus from the vein in the arm to the arteries in the neck. Since the arm and the chest are excluded from the field-of-vision of the detector, normally only minimal amounts of scattered radiations are detected during this peripheral inflow. I he average transit time of the passage of the bolus from the internal carotid artery to the torcular Herophili has been evaluated with various methods, to be 8±2 seconds.1 Thus, the next 3 frames represent the first circulation of the bolus into the head. They can often be identified in sequence as arterial frame, capillary frame and venous frame. The arterial frame is easily identified as the one on which the arteries in the neck and head are seen for the first time after injection. The venous frame of the first circulation is the first frame on which the longitudinal sinus is identified; the frame appearing between these 2 is the capillary frame. These 3 frames are by far the most important of the flow study. RESULTS ILLUSTRATIVE CASE A case of cervical venous reflux studied in detail is presented. On November I, 1972, a 37 year old patient underwent a routine anterior cerebral blood flow study and brain scan. The over-all examination was normal but a cervical venous reflux was identified (Fig. I, upper line). The next day, the patient returned for a control study under direct medical supervision. The attention of the patient was directed to prevent a Valsalva technique during the injection and the flow study. A cervical blood flow was then performed in the following manner: the patient was asked to put his head in extension and the collimator was centered over the neck. A cervical venous reflux was again observed (Fig. I, midline). The third day, the patient returned for a repeated control study agtin under direct medical supervision. This time, a diverging collimator was used and the patient was positioned far enough to include the chest and the neck in the field-of-vision of the collimator. No cervical reflux was observed. A normal pattern was obtained (Fig. i, lower line). INCIDENCE The radiopertechnetate flow study has been an inherent part of all br in scan ling performed in the division of Nuclear Medlcine since the acquisitio i of our gamma camera in Over this pei. d mote t an 1,500 studies a year have been performea. Patients with flow study or brain scan showing abnormal, unusual or asymmetric patterns were filed into a log book at the time of first reading with proper identfication of the patient, a descriptive sketch of the pattern and, whenever possible, its actual identification. A total of i8 cases was selected as cervical venous refluxes upon a review of our log books. It is thus conc uded that the occurrence of cervical venous reflux is extremely rare. This rare phenomenon has been observed in patients sitting, as well as in patients with normal and abnormal results. On control studies, it behaved inconstantly. DISCUSSION Cervical venous reflux is one of the numerous asymmetries, some technical, some pathologic and some a normal variant, that produce modified patterns during the first phase of the flow study (Table i). These patterns are classified into 2 groups: (a) those of the increased uptake type (cervical

3 278 Jacques Lamoureux JUNE, 1975 a... up in t....e ot the neck. 1..., in time, is a cervical venous rc.. Scatter radiation is also e as slight increased background activity in the right upper portion of the first frame. Middle Line-A control cervical blood flow study performed the next day again shows pooling on the last 3 frames. In addition, on the first frame uptake centrally located in the upper third stands out. It represents scattered radiation on the base of the chin, the head being in extension for the cervical flow study. Lower Line-The control study on the third day was performed with a diverging collimator centered over the neck and upper abdomen to detect the transit in the neck relative to the transit in the chest. The flow study, that day, was essentially normal, no cervical venous reflux was observed. venous reflux, scatter radiation, collimator leakage, and marginal showing of normally filled venous structures at the base of the TABLE PATTERNS OBSERVED DURING THE FIRST PHASE OF THE CEREBRAL BLOOD FLOW STUDY A. Patterns of the Increased Uptake Type a. Scatter radiation b. Collimator leakage c. Marginal showing of normally filled venous structures at the base of the neck d. Cervical venous reflux B. Patterns of the Decreased Uptake Type a. Missed injections b. Delayed onset of radionuclide circulation in normal young adults I neck); and (b) those of the decrease uptake type (missed injection, delayed onset of radionuclide circulation). Scatter radiation is routinely detected on the first frames of the first phase of the blood flow study. It vaguely depicts the position of the scattering surfaces in the field-of-vision of the collimator. On cerebral blood flow, an asymmetric accumulation of radiation is visualized along the side of the neck and head on the side of the injected arm (Fig. I, upper line, first frame). On cervical blood flow, the accumulation is seen centrally, reflecting the position of the base of the chin (Fig. I, midline, first frame). Its presence is predominant at the beginning of the study, because at that time

4 VOL. 124, No. 2 Cervical Venous Reflux 279 FIG. 2. Arteriovenous Ma/formation at C2-The posterior cerebral blood flow shows early increase of activi y in the left side of the neck on the arterial frame of the first circulation (upper line, second frame), then equalization on the capillary frame (upper line, third frame), and washout during the venous phase (lower line, first 2 frames). The posterior scan immediately following the flew study is essentially normal (lower line, last frame). the amount of scattered radiation in the field-of-vision, even if very small, is much more important than the primary radiation there. The pattern rapidly disappears with time as the amount of detected primary radiation over the head and neck increases with the arrival of the bolus. Collimator leakage produced a crescent lining of uptake spreading along the periphery oi the scintiphoto in the quadrant closest to the arm injected. It was predominant on the first frames of the flow study. This technical artifact resulted from an assemblage defect of a collimator. Its characteristic pattern has been described previously. Marginal showing of normally filled venous structures at the base of the neck occurs when the field-of-vision of the collimator is set low in the neck. The pattern is easily identified. It is mentioned here for the record. Delayed onset of radionuclide circulation into the head has been observed on very rare occasions in young adults. The pattern is characterized b a marked prolongation of the first phase of the flow stud. It is the onl unusual feature. The over-all study appears as if, after injection and removal of the rubber band, the bolus is detained somehow, thus delaying the onset of an otherwise normal first circulation pattern in the head. This pattern is markedly different from that of a missed injection. In

Flow patterns of cervical venous refluxes are easily differentiated from those of arteriovenous malformations.

5 280 Jacques Lamoureux JUNE, 1973 the latter case, low counts and ill-defined frames are obtained throughout the whole study. It is also different from the slow transit pattern observed in vascular disease.2 In these conditions the slow transit of the bolus occurs during both the inflow and the first circulation phases. Flow patterns of cervical venous refluxes are easily differentiated from those of arteriovenous malformations. The case of an arteriovenous malformation at the level of C2, in a 25 year old female, is presented (Fig. 2). The flow pattern in an arteriovenous malformation in the posteria fossa has been reported previously.4 The dominant feature of the pattern in these cases is paramount accumulation of uptake during the first arterial circulation of the radiopharmaceutical in the vessels of the neck and head and a return to baseline level by the end of this first circulation. This pattern is constant on repeated studies and is independent of the side of injection in the arm. The increased uptake in a cervical venous reflux builds up early in the neck, well in advance of opacification of the arteries in the neck and head. In some cases the increased uptake washes out without leaving any significant residual pooling in the neck. Then clearly follows, easily recognizable, the onset of the first arterial circulation of the bolus in the neck and head. In other cases, some of the bolus remains trapped in the venous structure of the neck and some of the bolus continues its normal course, giving rise on subsequent frames to the showing of a first circulation pattern of part of the bolus on which is superimposed the pooled activity detained in the neck and already visualized on the early frames of the flow study. The cervical venous reflux is predominant on the side of injection and behaves inconsistently on repeated studies. Then a repeated control study with injection in the contralateral arm contributes positive elements of differential diagnosis in dubious cases. CONCLUSION Cervical venous reflux is one of numerous asymmetries producing modified patterns during the first phase of the cerebral flow study. It is a rare phenomenon easily recognizable and easily differentiated from other patterns. Division of Nuclear Medicine Notre-Dame Hospital P.O. Box i6o Montreal, Quebec Canada H2L 4K8 REFERENCES i. ESPAGNO, J., et al. La circulation c#{233}r#{233}brale. Neurochirugie, 1969, 15, IMBORNE, C. J.,LANE, W., and GOoDwIN, D. A. Regional cerebral blood flow in cerebrovascular accidents and generalized cerebral arteriosclerosis by means of rapid serial -mm scintiphotographs. 7. Nuclear Med., 1968, 9, LAMOUREUX, J. Quality control: spot check to uncover collimator leakage. AM. J. ROENTGENOL., RAD. THERAPY & NUCLEAR MED., 1973, ii8, LAMOUREUX, J., BERTRAND, R. A., and VEZINA, J. L. Radiopertechnetate flow study: valuable adjunct to brain scanning in differential diagnosis of cerebello-pontine angle tumors. Laryngoscope, 1973, 83, OLDENDORF, W. H. Cerebral blood flow measurements. In: Recent Advances in Nuclear Medicine. Symposium Sponsored by the Department of Radiology of the Hahnemann Medical College. Appleton-Century-Crofts, New York, 1966, pp. 44-6I.

6 This article has been cited by: 1. Robert Zivadinov, Chih-Ping Chung Potential involvement of the extracranial venous system in central nervous system disorders and aging. BMC Medicine 11:1.. [CrossRef] 2. Chih-Ping Chung, Han-Hwa Hu Jugular Venous Reflux. Journal of Medical Ultrasound 16:3, [CrossRef] 3. R. M. Shore, B. K. Rao, O. B. Berg Massive jugular and dural sinus reflux associated with cerebral death. Pediatric Radiology 18:2, [CrossRef]

EXPERIMENTAL STUDIES OF THE SPLANCHNIC CIRCULATION OF THE RABBIT AFTER LIGATION OF THE SUPERIOR MESENTERIC ARTERY*

AUGUST, 1969 EXPERIMENTAL STUDIES OF THE SPLANCHNIC CIRCULATION OF THE RABBIT AFTER LIGATION OF THE SUPERIOR MESENTERIC ARTERY* II: RADIONUCLIDE TRACER STUDIES By FREDERICK J. BONTE, M.D., ROBERT W. PARKEY1