Case Report
Gadolinium-DTPA Enhanced MR Imaging of Intravenous Extension of Adrenocortical Carcinoma
T. H. M. Falke, J. J. Peetoom, A. de Roos, C. J. H. van de Velde, and M. Mazer
Abstract: A case of magnetic resonance imaging of adrenocortical carcinoma extending into the inferior vena cava is presented. Magnetic resonance was able to outline the intraluminal extent of tumor thrombus accurately. Signal intensity ratios (mean 0.98 ± 0.02) of tumor thrombus/primary tumor on T1- and T2-weighted sequences were useful for tissue characterization of tumor thrombus. Time course of the signal intensity of thrombus before and after intravenous administration of 0.1 mmol/kg gadolinium-diethylenetriamine pen- taacetic acid was identical to the primary tumor which aided in differentiation from nontumor thrombus. Index Terms: Vena cava, neoplasms-Adrenal gland, neoplasms-Gadolinium-DTPA-Magnetic resonance imaging.
Extension of adrenocortical carcinoma in the in- ferior vena cava (IVC) is well documented (1-4). Demonstration of such venous extension is impor- tant in staging and planning surgical resection. The relative merits of venacavography, ultrasound (US), and CT in the assessment of intravenous tumor thrombus in adrenocortical carcinoma and other abdominal carcinomas have been de- scribed (3).
Ultrasound and CT are useful alternatives to ve- nacavography. A major limitation of both modali- ties is the inability to differentiate tumor from non- tumor thrombi (3). Identification of tumor thrombus on nonenhanced magnetic resonance (MR) imaging has been only partially successful (2). In this paper we present our experience with gadolinium-diethyl- enetriamine pentaacetic acid (Gd-DTPA) enhanced MR to illustrate its potential to differentiate tumor from benign clot.
From the Department of Radiology (T. H. M. Falke, A. de Roos, and M. Mazer), Endocrinology (J. J. Peetoom), and Sur- gery (C. J. H. van de Velde), University Medical Center, Lei- den, The Netherlands. Address correspondence and reprint re- quests to Dr. T. H. M. Falke at Department of Diagnostic Ra- diology (C2-S), University Hospital Leiden, Niels Bohrweg 1, 2333 AA Leiden, The Netherlands.
MATERIALS AND METHODS
The patient was examined on a 0.5 T Philips MR scanner (Gyroscan S5). Multislice imaging included T1-weighted [echo time (TE) 20/repetition time (TR) 300, six averages] and T2-weighted (TE 50- 100/TR 2,000, two averages) transverse slices (thickness 10 mm, intersection gap 2 mm, acquisi- tion matrix 182 x 256, display matrix 256 x 256).
Selected transverse and coronal cardiac-gated multislice images were obtained at sites of interest through the heart and upper abdomen with a delay time of 200 ms. The pulse sequence used for the cardiac gated studies included a multislice spin echo (SE) TE 30/TR 400 and a multiecho multislice SE sequence (TE 30, 60, 90, 120/TR 400). Coronal T1- weighted multislice SE sequences (TE 20/TR 300, 6 averages) were obtained before and immediately af- ter intravenous administration of 0.1 mmol/kg body weight Gd-DTPA. The imaging following intrave- nous contrast medium enhancement with Gd-DTPA was repeated twice with an interval ~5 min.
Measurements of the average signal intensity (SI) of primary tumor, tumor thrombus, and liver were obtained for various sequences and following intra- venous contrast enhancement with Gd-DTPA. Av- erage SIs were produced from regions of interest positioned in several areas of the various tissues. Thrombus/primary tumor and primary tumor/liver
ratios for various sequences and time-intensity curves after intravenous injection of Gd-DTPA were calculated from these measurements. The presence and extension of the mass in the IVC was correlated with the findings on US, CT, arteriogra- phy, and surgery.
CASE REPORT
A 56-year-old woman had sudden onset of edema of the lower limbs. Previous history included virilizing symp- toms (increased facial hair and frontal balding) for 28 years. Hormonal evaluation showed high testosterone production, normal estrogen production, and low corti- sone production without diurnal rhythm. The excess tes- tosterone was not suppressed on 5-day administration of 3 mg dexamethasone.
Computed tomography and US revealed a left adrenal mass with extension into the IVC. Arteriography demon- strated a left adrenal mass with malignant tumor vascu- larity, compression of the normal renal parenchyma, and obstruction of the left renal vein and IVC. Determination of cranial extension of thrombus in the IVC was not es- tablished on CT, US, or arteriography nor could the na- ture of the intraluminal filling defect in the IVC be deter- mined. Cavography, both below and above the tumor, would probably have defined the extent of the intralumi- nal mass accurately but was not performed because of its potential risk.
Magnetic resonance confirmed the presence of a left adrenal mass separated from the upper pole of the left kidney by a low intensity pseudocapsule. Relative SIs of the mass to the liver on the T2-weighted sequence dem- onstrated an intermediate ratio (2.0 ± 0.3) compatible with adrenocortical carcinomas (Fig. 1) (5,6). Extension of the mass into the left renal vein and IVC was depicted as an endoluminal filling defect with enlargement of the lumen (Figs. 1 and 2). Invasion outside the venous wall
could be excluded. Cephalad extension of the filling de- fect into the right atrium was readily appreciated on the cardiac gated studies (Fig. 3). Signal intensities of the intraluminal mass were uniform and identical to the pri- mary tumor on all sequences (average ratio 0.98 ± 0.02). Time intensity curve of enhancement of the intraluminal mass following intravenous injection of Gd-DTPA was identical to the enhancement pattern of the primary tumor (Fig. 2, Fig. 4).
At thoracoabdominal surgery, the primary tumor and left kidney were removed. There was invasion of tumor into the left hemidiaphragm and continuity of the tumor mass into the IVC through the left renal vein. The bulk of the caval mass could be removed up to the level of the diaphragm leaving residual tumor in the right atrium. His- tological examination of tumor thrombus revealed mixed features of adenomatous and carcinomatous tumor of ad- renocortical origin.
DISCUSSION
A small percentage of primary carcinomas of the adrenal cortex may be complicated by extension into the IVC, usually through invasion of the adre- nal vein. The presence of these findings still war- rants surgical resection since complete removal of the thrombus is often feasible (3,4). In the event of wall invasion and extension into surrounding tis- sues, debulking prior to chemotherapy might also be considered. Accurate demonstration of the pres- ence and extension of tumor thrombus in the IVC prior to surgery is a prerequisite for successful sur- gical planning and can be demonstrated noninva- sively with US, CT, and MR. A major limitation of US and CT is their inability to differentiate tumor from benign clot (3,4) which may necessitate per- cutaneous or intraluminal biopsy (7).
1a,b
2a,b
P
a,b
1800
1600
1400
1200
ABSOLUTE SIGNAL INTENSITY (arbitrary units)
1000
tumor
800
+ thrombus
600
+ liver
400
200
0
1
0
5
10
15
TIME (minutes)
The use of MR to characterize the intraluminal pathology has been suggested (2). When signal within the vessel is identified, MR can distinguish between SI secondary to slow flow and SI indicat- ing true intraluminal thrombus by the phenomena of even echo rephasing (2,8) and use of phase dis- play (9).
The SI characteristics of the intravenous tumor extension on various pulse sequences in our case was identical to the primary tumor. This observa- tion suggests relative intensities of tumor thrombus/ primary tumor to be a useful criterion for differen- tiating tumor from nontumor thrombus. As previ- ously demonstrated a homogeneous, intermediate intensity signal on T2-weighted sequences may be produced in a small number of cases by blood clot. Therefore this distinction has to be made with some caution (2).
As demonstrated in our case intravenous Gd- DTPA may add confirmatory evidence that the in- travenous extension is indeed tumor thrombus based on intensity changes during enhancement es- pecially if intensity changes are similar to the inten- sity changes of the main tumor. Recently Gd-DTPA enhancement of adrenal tumors on MR has been demonstrated (10). The ideal time to image after Gd-DTPA has not been clearly identified and may differ for individual tumor pathology. Our clinical experience suggests that the preferred imaging time for adrenocortical carcinoma is immediately follow- ing Gd-DTPA. We recommend imaging over a 5 min time span followed by a repeat scan 5-10 min later.
Acknowledgment: This study was supported in part by Schering AG, Berlin-west and l’association poul l’etude et la Recherche en Radiologie (A.P.E.R.R.). The authors gratefully acknowledge the assistance of G. Kracht and J. L. Bloem.
REFERENCES
1. Dunnick NR, Doppman JL, Geelhoed GW. Intravenous ex- tension of endocrine tumors. AJR 1980;135:471-6.
2. Hricak H, Amparo E, Fisher MR, Crooks L, Higgins CB. Abdominal venous system: assessment using MR. Radiolo- gy 1985;156:415-22.
3. Cohn K, Gottesman L, Brennan M. Adrenocortical carcino- ma. Surgery 1986;100:1170-7.
4. Didier D, Racle A, Etievent JP, Weill F. Tumor thrombus of the inferior vena cava secondary to malignant abdominal neoplasms: US and CT evaluation. Radiology 1987;162: 83-9.
5. Reinig JW, Doppman JL, Dwyer AJ, Johnson AR, Knop RH. Adrenal masses differentiated by MR. Radiology 1986;158:81-4.
6. Falke THM, te Strake L, Sandler MP, et al. Magnetic reso- nance imaging of the adrenal glands. RadioGraphics 1987;7:343-70.
7. Mazer MJ, Cooper N, Falke T, Shaff M. MR imaging of the inferior vena cava (scientific exhibit 543). Radiology 1986;161(p):395.
8. Price RR, Falke THM, Pickens D. Blood flow in MR imag- ing. In: Partain CL, ed. Magnetic resonance imaging (MRI), vol 1. 2nd Ed. Philadelphia: WB Saunders, 1987.
9. White EM, Edelman RR, Wedeen VJ, Brady TJ. Intravas- cular signal in MR imaging: use of phase display for differ- entiation of blood-flow signal from intraluminal disease. Ra- diology 1986;161:245-9.
10. de Roos A, Doornbos J, Baleriaux D, Bloem JL, Falke THM. Clinical applications of gadolinium-DTPA in MRI. In: Kressel HY, ed. Magnetic resonance annual 1988. New York: Raven Press, 1988:113-45.