In-vitro high-resolution ultrasonography of benign and malignant lymph nodes. A sonographic-pathologic correlation

RATIONALE AND OBJECTIVES: The authors assess the value of combining high-resolution ultrasonography (HRUS) findings in a scoring scale for distinguishing malignant from reactive lymphadenopathy and explain the pathologic causes of altered nodal sonographic architecture. MATERIALS AND METHODS: Sixty-one nodes obtained from 32 consecutive patients were prospectively scanned with 7.5-MHz ultrasound probes in a waterbath. Three sonographic features--long-to-short axis ratio (L/S), hilar width, and cortical width--were graded on a 5-level scoring scale (0-4). Nodes scored > or = 3 were considered malignant and < or = 2 benign. Subsequently, all nodes were microsectioned in a plane matching the sonograms, allowing direct sonographic-pathologic correlation. RESULTS: Eighty-two percent of nodes were correctly characterized using the above cut-off point (sensitivity: 87%, specificity: 74%). Eighty-three percent of nodes scored 4 were malignant and 95% scored 0 were benign. Eighty-two percent of nodes with L/S < 2, 81% with no hilus, and 70% with eccentric cortical widening were malignant, whereas 72% with L/S > or = 2, 86% with a wide hilus, and 91% with a narrow cortex were benign. Sonographic-pathologic correlation showed that tumor infiltration results in rounded nodal shape, loss of hilar echogenicity and cortical widening, whereas reactive disease tends to preserve nodal architecture. CONCLUSION: Morphologic changes detectable using HRUS help distinguish benign from malignant lymph nodes.     

Differentiation between benign and metastatic cervical lymph nodes with ultrasound

OBJECTIVE: The differentiation between benign and metastatic lymph nodes with ultrasound (US) is based primarily on the evaluation of size, shape, margin and internal echo structure. The aim of this study is to determine whether these parameters are reliable indicators and to correlate internal echo structure and histopathological findings. MATERIALS AND METHODS: Seventy-one nodes in 21 patients with pathologically proven oral squamous cell carcinoma were examined. The shortest diameter, the short/long diameter ratio (S/L ratio), margins and internal echo structure of the lymph node were evaluated by US. The internal echo structure was divided into six patterns: homogeneous hypoechoic, homogeneous hyperechoic, heterogeneous, eccentric hyperechoic, centric hyperechoic and anechoic pattern. In addition, internal echo structure was correlated with histopathological findings. RESULTS: In 71.4% of the metastatic nodes, the shortest diameter was more than 10 mm and the S/L ratio was higher than that of benign nodes (average 0.71). Eleven (84.6%) of the 13 lymph nodes with irregular margins were metastatic. Heterogeneous and anechoic patterns were observed in metastatic nodes, whereas homogeneous hypoechoic and eccentric hyperechoic patterns were present in benign nodes. On ultrasonography with the corresponding histopathological findings, echogenic areas in the homogeneous hyperechoic, heterogeneous and centric hyperechoic patterns of metastatic nodes proved to be necrosis or fibrosis. Eccentric hyperechoic areas in benign nodes corresponded to the hilus and surrounding fatty tissue. CONCLUSIONS: The shortest diameter, S/L ratio, margin and internal echo structure were considered to be critical indicators to differentiate between benign and metastatic nodes. Secondary changes caused by tumour infiltration, necrosis, or fibrosis should be assessed when metastatic lymph nodes are differentiated from benign ones by internal echo structure.     

Care of the critically injured child: nonaccidental injuries

AIM: The established criteria for benignity or malignancy of lymph nodes when evaluated with B-mode ultrasound can be divided into quantitative measures (size, quantity, contour and density) and qualitative parameters (configuration and structure). The validity of these criteria is controversial. METHODS: Two cases of sinus histiocytosis with massive lymphadenopathy (SHML) are presented; this is a rare benign reactive disorder in which massive enlargement of cervical lymph nodes often occurs. These enlarged nodes offer a chance to demonstrate and discuss the validity of the sonomorphological criteria. RESULTS: The enlarged lymph nodes in SHML fulfill most of the criteria for malignancy. The same results are meet in other disorders with prominent but benign lymphadenopathy. CONCLUSION: The current ultrasonic criteria to determine benignity/malignancy in lymph nodes most likely simply indicate a large number of enlarged nodes. Pathologic diagnosis remains the gold standard.     

Diagnostic accuracy of sonographic criteria for evaluation of cervical lymphadenopathy

Although ultrasonographic criteria for abnormal nodes are used routinely in the evaluation of cervical lymphadenopathy, the diagnostic accuracy of these criteria in different areas has not been documented. This study evaluated 977 normal cervical nodes from 80 normal subjects and 1419 abnormal cervical nodes from 277 patients with proven cervical lymphadenopathy. The diagnostic accuracy (sensitivity, specificity, positive predictive value, negative predictive value, and accuracy) of size, shape (short axis to long axis ratio), echogenic hilus, and nodal border for regional lymph nodes are evaluated and discussed.     

Vascular pathology of malignant cervical lymphadenopathy: qualitative and quantitative assessment with power Doppler ultrasound

BACKGROUND: Malignant vascular pathology has traditionally been studied with invasive angiography or in vitro immunohistochemistry. The objective of this study was to investigate the vascular patterns and vascular density of benign and malignant cervical lymphadenopathy using power Doppler ultrasound combined with a computed quantitative image processing system. METHODS: Investigations of 189 cervical lymph node lesions were undertaken prospectively using a 5-10 MHz linear array transducer in power mode. The types of vascular patterns displayed with power Doppler ultrasound, after sweep-scanning over the whole lymph node, were classified as hilar, spotted, peripheral, or mixed. Quantitative assessment of vascularity was made by sampling three parallel planes of each lymph node. A computed image processing system automatically calculated the density of vascular signals (called the "vascularity index" in this study) within the lymph node plane. RESULTS: Malignant lymph node lesions were shown to have higher vascularity indices (0.169+/-0.147, P < 0.01). The vascular patterns of benign lesions were mostly of avascular or hilar type (in 83% of cases). Malignant lesions were characterized by patterns of mixed (47%), spotted (20%), or peripheral type (11%). When vascular pattern (nonhilar type) and vascularity index (maximum > or = 0.09) were combined, the specificity for diagnosing malignant lymphadenopathy was as high as 97%. Variance in tumor vascularity was noted in both the benign and malignant groups. CONCLUSIONS: Power Doppler ultrasound combined with a computed image processing system provided an objective tool for assessing tumor vascularity quantitatively. Using this modality, the vascular pathology of malignant lymphadenopathy was found to be characterized by higher vascular density and aberrant vascular patterns.     

Technetium-99m-tetrofosmin uptake in sarcoidosis stage I

The uptake of 99mTc-tetrofosmin in enlarged lymph nodes, of the lung hilus, in the case of sarcoidosis Stage I (histopathologically confirmed by mediastinoscopic biopsy) is demonstrated. On a routine chest radiograph of a 78-yr-old woman, hilar lymphadenopathy was first detected. In the following mammography, disseminated micro calcifications were found in the left breast and a 99mTc-tetrofosmin study was performed for detection of breast cancer. Scintigraphy using 99mTc-tetrofosmin showed clear uptake in the hilar lymph nodes, but not in the left breast. The 99mTc-tetrofosmin uptake in the hilar lymph nodes was due to sarcoidosis confirmed by histology. Therefore, 99mTc-tetrofosmin scintigraphy may be useful in patients with suspected sarcoidosis, especially in Stage I.     

Postarthroplasty histiocytic lymphadenopathy in gynecologic oncology patients. A benign reactive process that clinically may be mistaken for cancer

BACKGROUND: A distinctive histiocytosis occurs in the regional draining lymph nodes after large joint replacements, resulting in lymphadenopathy that may mimic cancer both grossly and microscopically. Postarthroplasty histiocytic lymphadenopathy has most often been observed in males during surgery for prostate cancer. METHODS: The authors present three examples of postarthroplasty histiocytic lymphadenopathy that occurred in gynecologic oncology patients. We studied the clinical, histologic, and immunohistochemical features of all three cases and the ultrastructure of one of them. RESULTS: Most involved lymph nodes were enlarged, but histiocytosis was also seen in normal sized lymph nodes. Microscopically, histiocytes with abundant granular cytoplasm were present in the lymph node parenchyma, and, to a lesser extent, in the sinuses. Normal lymph node architecture was variably effaced and the histiocytic infiltrate extended focally into the perinodal tissue. Small, black metal particles were present in the histiocytes in every case. Birefringent polyethylene particles were a prominent finding in all three cases as confirmed by positive modified oil red O staining, and, in one case, by electron microscopy. The histiocytes were strongly immunoreactive for CD68, but immunostains for S100 protein, MAC 387, and cytokeratin were negative. CONCLUSIONS: Enlargement of the lymph nodes in cancer patients who have had large joint replacements may be due to a benign histiocytosis rather than to metastatic cancer. The histologic features of the lymphadenopathy are distinctive and recognizable in routine histologic preparations. Polyethylene wear particles shed from joint prostheses are the most common substances in the histiocytes and are the most likely cause of the histiocytosis.     

Metastatic seminoma simulating malignant lymphoma in an HIV infected hemophiliac

Although most common, malignant lymphoma and Kaposi's sarcoma are not the only malignancies encountered in lymph nodes from HIV-infected patients. An increased frequency of testicular germ cell tumors in HIV-infected individuals has been reported. We report here the first case, to our knowledge, of a metastatic seminoma in an HIV-infected hemophiliac. The atypical clinical presentation, cervical and axillary adenopathy, simulated malignant lymphoma. The diagnosis was first suspected when a fine needle aspiration biopsy from an enlarged cervical node revealed a mixture of benign appearing lymphocytes and loosely cohesive large tumor cells in a "tigroid" background. Immunocytochemistry and a subsequent excisional biopsy confirmed the cytologic diagnosis. Metastatic germ cell tumors should be considered in the differential diagnosis of HIV-related lymphadenopathy.     

Ultrasonographic appearance of normal superficial cervical and subiliac lymph nodes in cattle

The superficial cervical and the subiliac lymph nodes of 18 healthy, non-pregnant Simmental cows with a mean (sd) age of 5-6 (1.6) years were examined ultrasonographically in transverse and longitudinal planes with a real-time B-mode unit equipped with a 7.5 MHz linear-transducer. The position, demarcation and echogenicity of the lymph nodes were examined, and the craniocaudal and lateromedial diameters of each lymph node were measured three times within a period of six weeks. The pole to pole length of the lymph nodes was determined with a tape measure on the surface of the skin because the whole length could not be imaged in a single scan field. The gross anatomical and histological results showed that the lymph nodes were normal. Ultrasonographically, they were well demarcated from the adjoining muscular and subcutaneous tissue. Their internal structure was characterised by an anechoic to hypoechoic cortical zone corresponding to the lymphoid tissue, and an echogenic medullary zone, where the lymphatic sinuses converge towards the hilus and produce numerous acoustic interfaces. In all the lymph nodes, the hilar area had an echoic to hyperechoic appearance. The mean (sd) pole to pole length of the superficial cervical lymph nodes was 15.5 (3.2) cm and of the subiliac lymph nodes 13.5 (2.4) cm. The mean craniocaudal and lateromedial diameters of the superficial cervical lymph nodes were 2.8 (0.3) cm and 1.6 (0.3) cm, and those of the subiliac lymph nodes were 2.4 (0.4) cm and 1.1 (0.3) cm. The ultrasonographic morphology of these normal lymph nodes was consistent and provides basic reference data for the investigation of lymphadenopathies in cattle.     

Intraductal ultrasound of the bile ducts

Intraluminal ultrasound with 12.5 and 20 MHz transducer allows precise analysis of the extrahepatic bile ducts and the adjacent structures. Inflammatory and malignant thickening of the bile duct wall can be assessed without difficulty. It is not possible, however, to differentiate between benign and malignant bile duct thickening, and for this purpose biopsy is required in addition. In tumor staging intraluminal ultrasound is superior to conventional ultrasound, because tumor infiltration into the adjacent tissues can be assessed and lymph nodes along the hepaticoduodenal ligament can be detected. Owing to the ultrasound frequencies available, local staging is limited to a circumference of 1.5/2 cm. Intraluminal ultrasound provides additional information that is useful in the diagnosis and therapy of bile duct stones and in different types of palliative tumor therapy. The procedure is simple and not too time consuming, and it involves no risks to the patient.     

Intrathoracic lymphadenopathy in patients with empyema

PURPOSE: Our goal was to determine the prevalence of intrathoracic lymphadenopathy on chest CT in patients with empyema. METHOD: We retrospectively identified 27 patients (14 men, 13 women, mean age 43 years) with nontuberculous empyema examined with chest CT. All scans were reviewed by two of three board-certified radiologists for the presence of intrathoracic lymphadenopathy (> or = 1 cm, short axis) in an American Thoracic Society (ATS) nodal station or the internal mammary region. Differences were resolved by consensus. RESULTS: Thirteen (48%) patients with empyema had lymphadenopathy on chest CT. The mean number of enlarged lymph nodes for the patients with lymphadenopathy was 3.2 (SD +/-2.3, range 1-8). The mean size of the largest lymph node was 1.4 cm (range 1.0-2.5 cm). The lymphadenopathy was unilateral and ipsilateral to the empyema in seven (54%), bilateral in five (38%), and unilateral contralateral to the empyema in one. The distribution of lymphadenopathy according to ATS nodal stations was 4R (n = 8), 7 (n = 6), 10R (n = 5); n = 2 each 2R, 10L, 11L; and n = 1 each 11R, 2L, 4L, and 6. Four patients had internal mammary lymphadenopathy. Pleural fluid and smooth pleural thickening were present in each case. Four patients had follow-up CT after treatment. There was a decrease or resolution of the lymphadenopathy in each case. CONCLUSION: Intrathoracic lymphadenopathy is a common CT finding in patients with empyema and occurred in 48% of this series. In patients with smooth pleural thickening and pleural effusion, intrathoracic lymphadenopathy should not be used as a criterion to differentiate empyema from malignant or tuberculous pleural effusion.     

Bartonella henselae infection in immunocompetent patients: cat scratch disease

BACKGROUND: Cat scratch disease, whose etiologic agent is Bartonella henselae, is a benign disease in immunocompetent subjects, characterized by lymphadenopathy of prolonged course and occasional involvement of other organs such as liver, spleen, central nervous system, eye and lung. In immunocompromised patients, the infection is bacteremic and disseminated. AIM: To report Chilean cases of cat scratch disease. PATIENTS AND METHODS: Ten children (seven male, aged between 6 and 13 years old) with histologically or serologically confirmed cat scratch disease are reported. RESULTS: Lymphadenopathy location was pre auricular in four cases, axillary in two, inguinal in two and epitrochlear in two. Three children had fever over 39 degrees C and two had a parinaud syndrome. Nine children had a history of cat scratch and one of a cat byte. Six had an erythrocyte sedimentation rate over 40. Lymph node ultrasound examination was a useful diagnostic tool. Two patients had splenic granulomas. Lymph node biopsies were obtained in four cases, showing a suppurative granulomatous lymphadenitis in all and a positive Warthin-Starry stain in two. Serology, done in patients without histological confirmation was positive with titles ranging from 1:64 to 1:8192. All patients had a satisfactory outcome with regression of lymphadenopathy. CONCLUSIONS: Infections by Bartonella hemselae occur in the Chilean population and must be considered in the differential diagnosis of regional lymph node enlargement.     

MR imaging of pelvic lymph nodes in primary pelvic carcinoma with ultrasmall superparamagnetic iron oxide (Combidex): preliminary observations

The potential of ultrasmall superparamagnetic iron oxide (Combidex)-enhanced MRI of pelvic lymph nodes in patients with primary pelvic carcinoma is evaluated. Fifteen histologically classified lymph nodes in six patients with known primary pelvic cancer (four prostate; one rectum; one uterus) were evaluated with T2-weighted fast spin-echo (FSE) and T2*-weighted gradient-echo (GRE) MRI at 1.5T 12 to 48 hours after intravenous administration of Combidex at a dose of 1.7 mg Fe/kg. Quantitative image evaluation was performed by comparing signal intensity of individual nodes on pre- and postcontrast images. All patients proceeded to pelvic lymph-node biopsy or surgical dissection, where six were found to be benign and nine were malignant. Of the 15 lymph nodes, four nodes showed a decrease in signal intensity. Of these, three, in which signal loss was homogenous were benign, and one, in which the signal-intensity decrease was heterogeneous, was malignant (micrometastases). No signal change was noted in 11 of 15 lymph nodes of which three were benign (inflammatory) and eight were malignant. Combidex is a promising MR contrast agent for evaluating pelvic lymph nodes. Our preliminary observations suggest that the agent is most useful for classifying normal lymph nodes.     

Metastasis of an adenocarcinoma of unknown origin to mediastinal lymph nodes, and transient regression

A 67-year-old woman was admitted to our hospital because of fever. Chest roentgenogram showed an enlargement of mediastinal lymph nodes. Despite thorough examination, no definite diagnosis could be made. The mediastinal lymph nodes got smaller over the next 3 weeks and a chest roentgenogram taken 4 months later showed no mediastinal lymphadenopathy. The mediastinal lymphadenopathy and fever recurred 5 months later. She underwent thoracotomy and the mediastinal lymph nodes were excised. Microscopic examination of pretracheal lymph node specimens showed invasion of poorly differentiated adenocarcinoma associated with abundant tumor-infiltrating lymphocytes. The other lymph nodes showed sarcoid reaction. Although she has been followed for one year and 11 months, no primary site of the cancer has been found. Metastasis of cancer of unknown origin to mediastinal lymph nodes is extremely rare. It is also interesting that the lymph node swelling diminished spontaneously. The tumor-infiltrating lymphocytes and sarcoid reactions may have been immunological responses to the cancer and may have caused the transient regression.     

Efficacy of sonographically guided biopsy of thyroid masses and cervical lymph nodes

OBJECTIVE: We performed a prospective study in 96 patients to determine accuracy of sonographically guided fine-needle aspiration biopsy of thyroid masses and cervical lymph nodes. MATERIALS AND METHODS: Real-time sonography was used to guide biopsy of 112 cervical masses in 96 patients (71 patients with impalpable masses, 16 with failed unguided attempts, patient's or physician's preference in nine). The diameters of all masses were less than 3 cm, with a mean of 1.5 cm and a median of 1.5 cm. Twenty-nine masses measured 1 cm or less in diameter, 60 masses between 1.1 and 2.0 cm, and 23 masses between 2.1 and 3.0 cm. Cervical masses that were sampled by biopsy included 75 thyroid masses and 37 lymph nodes. RESULTS: Diagnostic specimens were obtained in 102 (91%) of 112 masses sampled. Sixty-eight (91%) of 75 biopsies of thyroid tissue and 34 (92%) of 37 biopsies of lymph nodes were diagnostic. Nondiagnostic thyroid biopsies included four of complex cysts and three of solid nodules. Sonographic follow-up (1 year) revealed no change or decrease in size of those seven lesions. Sixty of 68 diagnostic thyroid biopsies showed benign processes: 42 macrofollicular adenomas, six colloid adenomas, five microfollicular adenomas, four probable cases of thyroiditis, and three hemorrhagic cysts. The remaining eight diagnostic thyroid biopsies showed malignant processes: seven papillary carcinomas and one metastatic small-cell carcinoma. Of 34 diagnostic biopsies of lymph nodes, 26 showed malignant processes and eight showed benign processes. Surgery in the three patients with nondiagnostic biopsies of lymph nodes revealed two recurrent medullary cancers and one benign node. CONCLUSION: Sonographically guided fine-needle aspiration biopsy of neck masses has a high sensitivity (91%) and should be routinely used to evaluate indeterminate masses in the neck.     

Distribution and contrast enhanced CT appearance of abdominal tuberculous lymphadenopathy

PURPOSE: To clarify the contrast enhanced CT features and anatomic distribution of the disseminated vs non-disseminated tuberculosis (TB) involving abdominal lymph nodes. MATERIALS AND METHODS: The contrast enhanced CT findings of abdominal lymphadenopathy in 25 patients, including disseminated TB associated with miliary TB of the lung (n = 5) and non-disseminated TB (n = 20), were retrospectively evaluated in a blind review to assess our criteria of morphology, density and location of the involved lymphadenopathy. RESULTS: The enhancement patterns of disseminated TB were not different from those of non-disseminated TB. Ninety-six percent of the patients had peripheral rim enhancement, and 60% showed a multilocular appearance. The enlarged lymph nodes of TB were less than 4 cm in diameter. Lymphadenopathy caused by hematogenous dissemination often accompanied splenic involvement showing multiple low-density foci in the spleen. The predominant sites of lymphadenopathy of disseminated TB were hepatoduodenal ligamentous, hepatogastric ligamentous, mesenteric, and both upper and lower portions of the retroperitoneal lymph nodes, whereas non-disseminated TB mainly involved hepatoduodenal ligamentous, hepatogastric ligamentous, mesenteric and upper retroperitoneal lymph nodes, excluding the lower retroperitoneal lymph nodes. By combining contrast enhancement patterns and the anatomic distribution of lymphadenopathy shown on the contrast enhanced CT images, reviewers made a correct diagnoses of tuberculosis in 94%, of cases, with a specificity of 95% and sensitivity of 92%. CONCLUSION: Contrast enhanced CT patterns correlate well with the pathologic features of tuberculous lymphadenopathy. A different anatomic distribution between disseminated and non-disseminated TB involving the lower retropentoneal lymph nodes was recognized in this study.     

Differentiation of benign and malignant cervical lymph nodes with color Doppler sonography

OBJECTIVE: This study proposed to evaluate the efficacy of color Doppler sonography in detecting possible differences in blood flow patterns between malignant and benign cervical lymph nodes. SUBJECTS AND METHODS: During a period of 12 months, the palpable cervical lymph nodes of 48 untreated patients were prospectively evaluated with color Doppler sonography and Doppler flow wave analysis. Histopathologic diagnoses were obtained by sonographically guided fine-needle aspiration biopsy and/or excisional biopsy. RESULTS: We found 16 benign lymph nodes (four were tuberculous lymphadenitis, four were reactive hyperplasia, and eight were unspecified) and 32 malignant lymph nodes (13 were squamous cell carcinomas, nine were adenocarcinomas, four were small-cell carcinomas, three were lymphomas, and three were miscellaneous). Color Doppler flow patterns were seen in six (38%) of the 16 benign lymph nodes and in 29 (91%) of the 32 malignant lymph nodes. Twenty-six (81%) of the 32 malignant lymph nodes had abnormal flow patterns, with resistance indexes less than 0.6. However, three (19%) of the 16 benign lymph nodes also had abnormal flow patterns, and only seven (54%) of 13 squamous cell carcinomas had abnormal flow patterns. CONCLUSION: Color Doppler sonography has limited clinical value in differentiating malignant from benign cervical lymph nodes and in obviating biopsy.     

Colour Doppler flow in normal axillary lymph nodes

81 women with carcinoma of the breast who underwent axillary nodal dissection were studied pre-operatively with colour Doppler ultrasound. The presence of colour Doppler flow was demonstrated in 83.6% of normal lymph nodes compared with 87.5% of metastatic lymph nodes. Using the presence of colour Doppler signal as the sole diagnostic criterion for the diagnosis of metastasis gave a sensitivity of 92.5%, specificity of 9.52%, accuracy of 50%, positive predictive value of 49.3% and negative predictive value of 57.1%. Using grey scale sonographic criteria, where a metastatic node was defined as a node with loss of central fatty hilum and/or eccentric cortical hypertrophy, a sensitivity of 79.5%, specificity of 94.0%, accuracy of 87.6%, positive predictive value of 91.2% and negative predictive value of 85.5% were obtained. Colour Doppler studies of the axillary nodes in a second group of 106 women who attended for breast cancer screening and had no significant breast or axillary pathology also showed colour Doppler signal in 86.7% of nodes. It is concluded that colour Doppler flow signals can be demonstrated in both normal and metastatic axillary lymph nodes, and is highly non-specific when used as the sole diagnostic criterion in the diagnosis of malignancy.     

The value of the CT scanner in intensive care

The composition of atherosclerotic plaques in the carotid artery is assumed to be related to the development of neurological symptoms. The echo patterns produced by B-mode ultrasound may be of use in the assessment of the plaques' composition. It is suggested that fibrotic and "stable" plaques are more echogenic than lipid/hemorrhagic and echolucent or "unstable" plaques. B-mode ultrasound procedures were performed 1 day prior to surgery on 46 consecutive endarterectomies. Two observers assessed the plaques according to their echo pattern and echogenicity and sorted them into three categories: 1) predominantly echolucent, 2) heterogeneous, and 3) predominantly echogenic. The intraobserver agreement was moderate (kappa = 0.44) and the interobserver agreement low (kappa = 0.38). Furthermore, subjective categorization of plaque types resulted in type 1 plaques being as fibrotic as type 2 or 3 plaques. We conclude that B-mode ultrasound and subsequent subjective categorization of atherosclerotic plaques cannot adequately determine the volume of fibrosis or lipids within the plaque.