Work In Progress
WORK IN PROGRESS wish to discuss our technique and findings in 12 patients, of whom 7 were studied because of a mass, 2 had Sjogren syndrome, 2 had traumatic les ion s, and 1 was thought to have a fungal infection of the parotid.
Computed Tomography of the Parotid Gland During Contrast Sialography 1 Anthony Mancuso, M.D., Dale Rice, M.D., and William Hanafee, M.D. By performing CT scanning during contrast sialography, tumors within the parotid gland can be shown and their configuration in relation to the remaining normal salivary gland and surrounding structures can be appreciated. This permits better evaluation of the relationship of the tumor to the facial nerve, possible extension of tumor beyond the gland, and benign versus malignant growth characteristics. Computed tomography, he a d » Parotid gland. neoplasm s • Salivary glands, radiography, 2[ 64 J.1222 (Salivary gland, C.T., 21641 121 1)
INDEX TERMS:
Radiology 132:211 -213, July 1979
Preliminary experience suggests that CT scanning during injection for parotid sialography is superior to either modality alone, locating tumors more accurately with in the parotid gland and displaying their gross characteristics in greater detail. We
TECHNIQUE We use an EMI5005 CT scanner at 1.0- or 0 .5-cm intervals, beginning at the inferior margin of the external auditory canal and progressing until the inferior marg in of the parotid gland has been covered, which usually takes six or seven scans. The opening of Stensen 's duct is cannulated using a Rabinov catheter or a blunt-needle cannula w ith an approximately 21 gauge tip. A 30 .5-3B-cm (12-15-in.) length of extension tubing is attached to the needle or catheter for the contrast injections. A 10-ml syringe is filled with 60 % or 76 % methylglucamine diatrizoate and is handed to the patient when he is in position in the CT scanner. The patient is instructed to make his own contrast injection when we signal that scanning may begin. He continues to inject contrast material even after perceiving fullness in the parotid gland , until he actually feels pain; at this point he stops the injection and waves at us to start the scan. The pa in is an indication that all of the ducts are completely filled and parenc hymal staining has begun (Fig. 1, a and b). The patient repeats
1 a.b
Fig. 1. a. Axial section through the midportion of a normal parotid gland. The gland parenchyma ishomogeneously stained (arrows). including both the deep lobe (0) and the superficial portion (S). The small posterior defect (arrowheads)is caused by the sternocleidomastoid muscle (M). The gland wraps around the masseter muscle (MA) anteriorly. The styloid process (sp) marks the region of the facial nerve trunk; the remainder of the nerve courses anterolaterally through the gland (dotted line). b. Section 2 em lower on the opposite (right) side. The main parotid duct (white arrow) passes through the buccal fat pad (8). Just behindthe mandible (M) is a defect caused by the digastric muscle (between black arrows). Posteriorly, the sternocleidomastoid defect again creates a small. symmetrical impression on the gland. (NOTE: Parts c -f are on the next page)
211
212
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July 197 9
1 c,d
c. Section through the midportion of the parotid in a patient with tumor. The patchy, irregular staining (arrows) is consistent with diffuse superficial (s) and deep (d) involvement of the lobe. m = inferior tip of the mastoidprocess; sp = styloid process. d. Lower section showsa lobulated exophytic portion of the mass(whitearrows) growing out of the glandand invading the sternocleidomastoid (scm) , as indicated by the black arrows. Tumor was confirmed at surgery. e. Spreading of the ducts (arrows) indicates a benign mixed tumor. The remainderof the gland (PG) is homogeneously stained. f. Note the smooth-contourbd filling defect at the junction of the superficial and deep lobes (arrowheads). At this level, the styloid process (s) roughlymarks the plane of the facial nerve. At surgery. the nerve wasdisplacedmediallyand the main trunk could not be isolated. so that the nerve had to be dissected in a retrograde fashion.
the injection for each section. Bilateral studies are routinely performed; 10 ml of contrast material will usually suffice for both sides. In our comparative study, conventional sialography was performed either before or after CT sialography . RESULTS Although surgical confirmation of the diagnosis has not been obtained in all cases, the clarity of the CT scans is impressive enough to warrant further study. Axial tomography permitted a better appreciation of the location and direction of growth of tumor in 6 of the 7 patients with a mass. The single malignant parotid tumor was so obvious on the CT sialogram that a preoperative diagnosis of malignancy could, be made with confidence. The origin of the lesion in the deep lobe of the parotid was evident and there was a marked lobulated, irregular pattern which
indicated extension of tumor beneath the sternocleidomastoid muscle (Fig. 1, c and d). This is quite different from the round. sharply circumscribed appearance of benign tumors (Fig. 1. e and f). The facial nerve exits immediately lateral to the styloid process and courses anter iorly adjacent to the major ducts within the parotid; thus. since the styloid process is consistently visualized on CT scans, one can pred ict whether the mass will be superficial or deep to the facial nerve (1) (Fig. 1, e and f). More experience is needed before the accuracy of CT sialography in diagnosing chronic punctate sialadenitis can be established . In our first 2 patients, the collections of contrast material in the ectatic ducts were larger and more widely separated from adjacent collections of contrast material than usual; this is consistent with the atrophy and cellular infiltration seen in this condition.
213
WORK IN PROGRESS
Vol. 132
DISCUSSION The role of sialography remains controversial, especially for demonstrating tumors 1.0 em or less (1). Planning of operative management and preoperative instruction of the patient are just as important as diagnosis. Determination of accuracy will require a greater number of patients and precise operative correlation. The modern approach for biopsy of a parotid mass is superficial parotidectomy. In this approach the operator locates the facial nerve at the stylomastoid foramen and makes his surgical cleavage plane by identifying the branches of the facial nerve. If the tumor prevents isolation of the facial nerve trunk at the stylomastoid foramen, he may have to reverse his approach and trace the branches of the facial nerve in a retrograde fashion, even though this is more time-consuming and increases the risk of facial nerve injury. CT scanning offers great promise in providing this type of information preoperatively. Preoperative discussion of potential postoperative deformities with the patient is of great importance. If malignancy can be suggested with a high degree of assurance, the patient can be better prepared for the ensuing facial paralysis and the possibility of a radical temporal bone resection. Biopsy will still be necessary, but he is at least given the opportunity of a preoperative decision to elect irradiation as the primary method of treatment.
Work In Progress
Having the patient perform his own contrast injections makes CT sialography a good deal faster and enables the radiologist to monitor the CT images more closely. Patients also tend to feel more comfortable because they are in direct control of the amount of pain associated with the examination. ADDENDUM: After this paper was accepted for publication, it was discovered that a similar technique had been described by Carter and Karmody. These authors suggest that CT be done immediately following sialography; our experience, as stated in this report, is that it is best to do CT and sialography simultaneously. Carter Bl, Karmody CS: Computed tomography of the face and neck. Semin Roentgenol 13:257-266. Jul 1978
REFERENCE 1. Calcaterra TC, Hemenway WG, Hansen GC, et al: The value of sialography in the diagnosis of parotid tumors. A clinicopathological correlation. Arch OtolaryngoI103:727-729, Dec 1977 1 From the Departments of Radiology (A.M .. Assistant Professor; W.H., Professor) and Surgery (D.R., Assistant Professor), UCLA Center for the Health Sciences. los Angeles. Calif. 90024 (reprint requests to W.H.). Received Jan. 11. 1979 and accepted Feb. 27. This work was supported in part by grant 5F32 NS 05771-02 from the National Institute of Neurological and Communicative Disorders and Stroke and in part by the leo G. Rigler Center for Radiologic Research. sjh
WORK IN PROGRESS wish to discuss our technique and findings in 12 patients, of whom 7 were studied because of a mass, 2 had Sjogren syndrome, 2 had traumatic les ion s, and 1 was thought to have a fungal infection of the parotid.
Computed Tomography of the Parotid Gland During Contrast Sialography 1 Anthony Mancuso, M.D., Dale Rice, M.D., and William Hanafee, M.D. By performing CT scanning during contrast sialography, tumors within the parotid gland can be shown and their configuration in relation to the remaining normal salivary gland and surrounding structures can be appreciated. This permits better evaluation of the relationship of the tumor to the facial nerve, possible extension of tumor beyond the gland, and benign versus malignant growth characteristics. Computed tomography, he a d » Parotid gland. neoplasm s • Salivary glands, radiography, 2[ 64 J.1222 (Salivary gland, C.T., 21641 121 1)
INDEX TERMS:
Radiology 132:211 -213, July 1979
Preliminary experience suggests that CT scanning during injection for parotid sialography is superior to either modality alone, locating tumors more accurately with in the parotid gland and displaying their gross characteristics in greater detail. We
TECHNIQUE We use an EMI5005 CT scanner at 1.0- or 0 .5-cm intervals, beginning at the inferior margin of the external auditory canal and progressing until the inferior marg in of the parotid gland has been covered, which usually takes six or seven scans. The opening of Stensen 's duct is cannulated using a Rabinov catheter or a blunt-needle cannula w ith an approximately 21 gauge tip. A 30 .5-3B-cm (12-15-in.) length of extension tubing is attached to the needle or catheter for the contrast injections. A 10-ml syringe is filled with 60 % or 76 % methylglucamine diatrizoate and is handed to the patient when he is in position in the CT scanner. The patient is instructed to make his own contrast injection when we signal that scanning may begin. He continues to inject contrast material even after perceiving fullness in the parotid gland , until he actually feels pain; at this point he stops the injection and waves at us to start the scan. The pa in is an indication that all of the ducts are completely filled and parenc hymal staining has begun (Fig. 1, a and b). The patient repeats
1 a.b
Fig. 1. a. Axial section through the midportion of a normal parotid gland. The gland parenchyma ishomogeneously stained (arrows). including both the deep lobe (0) and the superficial portion (S). The small posterior defect (arrowheads)is caused by the sternocleidomastoid muscle (M). The gland wraps around the masseter muscle (MA) anteriorly. The styloid process (sp) marks the region of the facial nerve trunk; the remainder of the nerve courses anterolaterally through the gland (dotted line). b. Section 2 em lower on the opposite (right) side. The main parotid duct (white arrow) passes through the buccal fat pad (8). Just behindthe mandible (M) is a defect caused by the digastric muscle (between black arrows). Posteriorly, the sternocleidomastoid defect again creates a small. symmetrical impression on the gland. (NOTE: Parts c -f are on the next page)
211
212
WORK
IN PROGRESS
July 197 9
1 c,d
c. Section through the midportion of the parotid in a patient with tumor. The patchy, irregular staining (arrows) is consistent with diffuse superficial (s) and deep (d) involvement of the lobe. m = inferior tip of the mastoidprocess; sp = styloid process. d. Lower section showsa lobulated exophytic portion of the mass(whitearrows) growing out of the glandand invading the sternocleidomastoid (scm) , as indicated by the black arrows. Tumor was confirmed at surgery. e. Spreading of the ducts (arrows) indicates a benign mixed tumor. The remainderof the gland (PG) is homogeneously stained. f. Note the smooth-contourbd filling defect at the junction of the superficial and deep lobes (arrowheads). At this level, the styloid process (s) roughlymarks the plane of the facial nerve. At surgery. the nerve wasdisplacedmediallyand the main trunk could not be isolated. so that the nerve had to be dissected in a retrograde fashion.
the injection for each section. Bilateral studies are routinely performed; 10 ml of contrast material will usually suffice for both sides. In our comparative study, conventional sialography was performed either before or after CT sialography . RESULTS Although surgical confirmation of the diagnosis has not been obtained in all cases, the clarity of the CT scans is impressive enough to warrant further study. Axial tomography permitted a better appreciation of the location and direction of growth of tumor in 6 of the 7 patients with a mass. The single malignant parotid tumor was so obvious on the CT sialogram that a preoperative diagnosis of malignancy could, be made with confidence. The origin of the lesion in the deep lobe of the parotid was evident and there was a marked lobulated, irregular pattern which
indicated extension of tumor beneath the sternocleidomastoid muscle (Fig. 1, c and d). This is quite different from the round. sharply circumscribed appearance of benign tumors (Fig. 1. e and f). The facial nerve exits immediately lateral to the styloid process and courses anter iorly adjacent to the major ducts within the parotid; thus. since the styloid process is consistently visualized on CT scans, one can pred ict whether the mass will be superficial or deep to the facial nerve (1) (Fig. 1, e and f). More experience is needed before the accuracy of CT sialography in diagnosing chronic punctate sialadenitis can be established . In our first 2 patients, the collections of contrast material in the ectatic ducts were larger and more widely separated from adjacent collections of contrast material than usual; this is consistent with the atrophy and cellular infiltration seen in this condition.
213
WORK IN PROGRESS
Vol. 132
DISCUSSION The role of sialography remains controversial, especially for demonstrating tumors 1.0 em or less (1). Planning of operative management and preoperative instruction of the patient are just as important as diagnosis. Determination of accuracy will require a greater number of patients and precise operative correlation. The modern approach for biopsy of a parotid mass is superficial parotidectomy. In this approach the operator locates the facial nerve at the stylomastoid foramen and makes his surgical cleavage plane by identifying the branches of the facial nerve. If the tumor prevents isolation of the facial nerve trunk at the stylomastoid foramen, he may have to reverse his approach and trace the branches of the facial nerve in a retrograde fashion, even though this is more time-consuming and increases the risk of facial nerve injury. CT scanning offers great promise in providing this type of information preoperatively. Preoperative discussion of potential postoperative deformities with the patient is of great importance. If malignancy can be suggested with a high degree of assurance, the patient can be better prepared for the ensuing facial paralysis and the possibility of a radical temporal bone resection. Biopsy will still be necessary, but he is at least given the opportunity of a preoperative decision to elect irradiation as the primary method of treatment.
Work In Progress
Having the patient perform his own contrast injections makes CT sialography a good deal faster and enables the radiologist to monitor the CT images more closely. Patients also tend to feel more comfortable because they are in direct control of the amount of pain associated with the examination. ADDENDUM: After this paper was accepted for publication, it was discovered that a similar technique had been described by Carter and Karmody. These authors suggest that CT be done immediately following sialography; our experience, as stated in this report, is that it is best to do CT and sialography simultaneously. Carter Bl, Karmody CS: Computed tomography of the face and neck. Semin Roentgenol 13:257-266. Jul 1978
REFERENCE 1. Calcaterra TC, Hemenway WG, Hansen GC, et al: The value of sialography in the diagnosis of parotid tumors. A clinicopathological correlation. Arch OtolaryngoI103:727-729, Dec 1977 1 From the Departments of Radiology (A.M .. Assistant Professor; W.H., Professor) and Surgery (D.R., Assistant Professor), UCLA Center for the Health Sciences. los Angeles. Calif. 90024 (reprint requests to W.H.). Received Jan. 11. 1979 and accepted Feb. 27. This work was supported in part by grant 5F32 NS 05771-02 from the National Institute of Neurological and Communicative Disorders and Stroke and in part by the leo G. Rigler Center for Radiologic Research. sjh
