Minimally Invasive Diagnosis of Secondary Intracranial Lymphoma.

Diffuse large B cell lymphomas (DLBCL) are an aggressive group of non-Hodgkin lymphoid malignancies which have diverse presentation and can have high mortality. Central nervous system relapse is rare but has poor survival. We present the diagnosis of primary mandibular DLBCL and a unique minimally invasive diagnosis of secondary intracranial recurrence. This case highlights the manifold radiological contributions to the diagnosis and management of lymphoma.

Is diffusion-weighted MRI sufficient for follow-up of neuroendocrine tumour liver metastases?

AIM: To assess if diffusion-weighted imaging (DWI) alone could be used for follow-up of neuroendocrine hepatic metastases. MATERIAL AND METHODS: This was a retrospective study, approved by the institutional review board. Twenty-two patients with neuroendocrine liver metastases who had undergone more than one liver magnetic resonance imaging (MRI) examination, (including DWI and using hepatocyte-specific contrast medium) were evaluated. Up to five metastases were measured at baseline and at each subsequent examination. The reference standard measurement was performed on the hepatocyte phase by one reader. Three independent readers separately measured the same lesions on DWI sequences alone, blinded to other sequences, and recorded the presence of any new lesions. RESULTS: The longest diameters of 317 liver metastases (91 on 22 baseline examinations and a further 226 measurements on follow-up) were measured on the reference standard by one reader and on three b-values by three other readers. The mean difference between DWI measurements and the reference standard measurement was between 0.01-0.08 cm over the nine reader/b-value combinations. Based on the width of the Bland and Altman interval containing approximately 95% of the differences between the reader observation and the mean of reference standard and DWI measurement, the narrowest interval over the nine reader/b-value combinations was -0.6 to +0.7 cm and the widest was -0.9 to 1 cm. In the evaluation of overall response using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria, the weighted kappa statistic was between 0.49 and 0.86, indicating moderate-to-good agreement between the reference standard and DWI. CONCLUSION: The visualisation and measurement of hepatic metastases using DWI alone are within acceptable limits for clinical use, allowing the use of this rapid technique to restage hepatic disease in patients with neuroendocrine metastases.

Role of bone scan in addition to CT in patients with breast cancer selected for systemic staging.

BACKGROUND: The majority of women with breast cancer present with localized disease. The optimal strategy for identifying patients with metastatic disease at diagnosis remains unclear. The aim of this study was to evaluate the additional diagnostic yield from isotope bone scanning when added to CT staging of the thorax, abdomen and pelvis (CT-TAP) in patients with newly diagnosed breast cancer. METHODS: All patients diagnosed with breast cancer who underwent staging CT-TAP and bone scan between 2011 and 2013 were identified from a prospective database of a tertiary referral breast cancer centre that provides a symptomatic and population-based screening breast service. Criteria for staging included: biopsy-proven axillary nodal metastases; planned neoadjuvant chemotherapy or mastectomy; locally advanced or inflammatory breast cancer and symptoms suggestive of metastases. RESULTS: A total of 631 patients underwent staging by CT-TAP and bone scan. Of these, 69 patients (10·9 per cent) had distant metastasis at presentation, with disease confined to a single organ in 49 patients (71 per cent) and 20 (29 per cent) having metastatic deposits in multiple organs. Bone metastasis was the most common site; 39 of 49 patients had bone metastasis alone and 12 had a single isolated metastatic deposit. All but two of these were to the axial skeleton. No preoperative histological factors identified a cohort of patients at risk of metastatic disease. Omission of the bone scan in systemic staging would have resulted in a false-negative rate of 0·8 per cent. CONCLUSION: For patients diagnosed with breast cancer, CT-TAP is a satisfactory stand-alone investigation for systemic staging.

Should abdominal sequences be included in prostate cancer MR staging studies?

OBJECTIVES: Prostate cancer staging MR examinations commonly include abdominal sequences to assess for non-regional (common iliac or para-aortic) nodal metastasis. In our experience the diagnostic yield of this is limited, but incidental findings are frequent, often necessitating further investigations. The aim of this study is to assess the diagnostic utility of abdominal sequences in routine prostate cancer MR staging studies. METHODS: Findings on abdominal sequences of consecutive MRI prostate studies performed for staging newly diagnosed prostate cancer between September 2011 and September 2013 were reviewed with respect to adenopathy and additional incidental findings. Results were correlated with Gleason grade and serum prostate-specific antigen (PSA) level in each case. RESULTS: 355 MRI prostate examinations were reviewed. 4 (1.1%) showed enlarged non-regional lymph nodes. Incidental findings were found in 82(23.1%) cases, neccessitating further investigation in 45 (12.7%) cases. Enlarged non-regional nodes were associated with higher PSA level and Gleason grade (p=0.007, p=0.005 respectively). With a combined threshold of PSA > 20 ng/mL and/or Gleason grade ≥ 8 the sensitivity, specificity, PPV and NPV were 100, 60, 3 and 100% respectively for predicting the presence of non-regional adenopathy. CONCLUSIONS: Routine abdominal sequences are of very low yield in routine prostate cancer MR staging, frequently resulting in incidental findings requiring further work-up and should be reserved for high-risk cases. Our experience supports the use of an abdominal staging sequence in high-risk cases only.

Incidental Phaeochromocytoma on Staging PET-CT in a Patient with a Sigmoid Tumour and Situs Inversalis Totalis.

An adrenal "incidentaloma" is defined as an unexpected finding on radiological imaging performed for unrelated indications. Improvements in radiological technology have seen a dramatic increase in this phenomenon. We report the unique case of a 60-year-old female presenting with a 6-month history of abdominal pain, altered bowel habit, and rectal bleeding. Her past medical history included situs inversus totalis and a patent ductus arteriosus. Colonoscopy revealed an ulcerated tumour in her sigmoid colon. Staging PET-CT confirmed a sigmoid tumour and also identified a large heterogenous enhancing FDG-avid right adrenal mass. Biochemical testing/MIBG imaging confirmed a right adrenal phaeochromocytoma. Hypertension was controlled and excision was performed via a transperitoneal laparoscopic adrenalectomy, in the left lateral decubitus position. Uniquely, liver retraction was not required due to its position in the left hypochondrium. Histology confirmed a benign 46 mm phaeochromocytoma. Subsequent uncomplicated sigmoid colectomy/right salpingo-oophorectomy for a locally advanced colonic tumour was performed with adjuvant chemotherapy. This case highlights the importance of accurately identifying functioning adrenal tumours before elective surgery as undiagnosed phaeochromocytomas carry significant intraoperative morbidity/mortality. Right adrenalectomy was made easier in this patient by the liver's unique position. Uncomplicated colorectal resection was made possible by combined preoperative functional/anatomical imaging.

Diagnostic performance of MDCT, PET/CT and gadoxetic acid (Primovist(®))-enhanced MRI in patients with colorectal liver metastases being considered for hepatic resection: initial experience in a single centre.

PURPOSE: To compare the relative diagnostic performance of MDCT, PET/CT and Primovist-enhanced MRI (P-MRI) in the pre-resection work-up of colorectal cancer (CRC) liver metastases. METHOD AND MATERIALS: This was a retrospective study of consecutive referrals for CRC liver metastases. All patients had MDCT, PET/CT and P-MRI examinations within 3 months of each other. They were divided into 2 groups: resected and unresected. Patients in the resected group underwent liver resection within 3 months of the imaging studies. In the unresected group, patients were unresectable by imaging criteria or are awaiting surgery. Standard of reference (SOR) was intra-operative ultrasound findings and pathology for the resected group. Intermodality comparison was the SOR for the unresected group. Number of lesions identified by each imaging modality for each patient was recorded. Sensitivity (95% CI) and PPV were calculated for each imaging modality in the resected group. RESULTS: There were 19 patients in the resected group and 11 patients in the unresected group. The sensitivity (96%) and PPV (0.91) of P-MRI were both superior to that of MDCT (P = 0.0009) and PET/CT (P = 0.0003). Intermodality comparison showed that P-MRI detected more lesions than MDCT and PET/CT. CONCLUSION: The sensitivity and PPV of P-MRI was superior to that of MDCT and PET/CT. P-MRI probably has the most added value if used after MDCT and PET/CT in patients still considered eligible for liver resection.

Sentinel lymph node biopsy in elderly irish patients with malignant melanoma.

In patients with malignant melanoma, Breslow depth increases with age. However, studies suggest that the frequency of sentinel lymph node metastases in malignant melanoma decreases with age. We investigated whether this applied to the cohort of patients undergoing sentinel lymph node biopsy (SLNB) in our institution. In a prospectively accrued database we identified 149 patients undergoing SLNB from 1997 to 2005. Tumour thickness as measured by Breslow depth was assessed in stratified age groups. We assessed the relationship between SLNB positivity and age using the Chi-square for trend. We directly examined the relationship between SLNB positivity in patients aged less than 65 and aged 65 years of age and over. Disease-free and overall survival in patients aged less than 65 and aged 65 years of age and over were also assessed. Comparing the age groups, there was no significant difference identified in Breslow depth (<65 years, median Breslow > or = 1.2 mm (range 0.2-9.7); > or =65 years, median Breslow > or = 1.4 mm (range 0.12-8.5); p > or = 0.06, Mann-Whitney U). Chi-square for trend identified no significant relationship between SLNB positivity and age. We found n=120 patients <65 had SLNB, of which 26 (21.7%) were positive. In patients =65, n=29 had SLNB of which 3 (10.3%) were positive. These differences were not statistically significant (Fisher's exact test, p > or = 0.2). There was no difference in disease-free or overall survival between patients aged <65 or > or =65 who had SLNB (median follow-up 37.5 months (range 5-70); disease-free survival, p > 0.08; overall survival, p > or = 0.3, Logrank test). We did not find that elderly patients with malignant melanoma had a demonstrable difference in tumour thickness when compared to younger patients. In those patients who underwent SLNB there was no significant difference in node positivity between the age groups. Disease-free and overall survival were not significantly different between the age groups. Further study and longer follow-up will help establish the relationship between age and SLNB positivity.

Positron emission tomography in the staging and management of breast cancer.

BACKGROUND: Breast cancer is the commonest cause of cancer death in women in the Western world, and imaging is essential in its diagnosis and staging. Metabolic imaging is a novel approach to improving the detection of cancers, as malignant transformation of cells is often associated with increased metabolic activity. This review assesses the possible role of positron emission tomography (PET) as a single non-invasive imaging modality to replace or complement current imaging and surgical practices in the diagnosis and staging of breast cancer. METHODS AND RESULTS: A Medline search was performed and articles were cross-referenced with other relevant material. Evaluation of primary breast cancer with PET has shown a sensitivity of between 64 and 100 per cent and a specificity of 33-100 per cent; diagnostic accuracy appears to be related to tumour size. Difficulties arise in altered fluorodeoxyglucose uptake in lobular carcinoma, carcinoma in situ and benign inflammatory breast disease. In axillary staging, sensitivities of between 25 and 100 per cent have been reported, but with a false-negative of up to 20 per cent. In the assessment of distant metastasis and asymptomatic patients with raised levels of tumour markers, PET was superior to conventional imaging modalities. CONCLUSION: PET is not a single diagnostic and staging tool that can replace current surgical, histological and radiological staging. Its main role in breast cancer lies in the investigation of metastatic disease and the evaluation of pathological response to various chemotherapeutic regimens.

Positron emission tomography for staging and management of malignant melanoma.

BACKGROUND: The incidence of malignant melanoma is rising; it now has an incidence of ten per 100 000 per annum in the UK. The development of metastases is unpredictable, but prognosis is linked directly to the initial stage at diagnosis. Positron emission tomography (PET) can allow the detection of malignant cells at a relatively early stage. METHODS: A review of the literature was undertaken by searching the Medline database for the period 1980-2000 without any language restrictions. RESULTS: The overall sensitivity and specificity of PET are 74-100 and 67-100 per cent respectively. PET has a reduced sensitivity and specificity for thinner lesions (less than 1 x 5 mm). Comparison with computed tomography and magnetic resonance imaging has shown a higher sensitivity and specificity for PET in all regions of the body except the thorax. CONCLUSION: Currently the accepted indication for PET is recurrent melanoma when surgical intervention is being considered. However, other potential indications include the detection of occult or distant metastasis at initial presentation and the clarification of abnormal radiological findings at follow-up. The routine use of PET for American Joint Commission on Cancer stage I or II disease is of uncertain benefit and is not indicated at present.

Selection of patients for resection of hepatic metastases: improved detection of extrahepatic disease with FDG pet.

A rapidly emerging clinical application of positron emission tomography (PET) is the detection of tumor tissue at whole-body studies performed with the glucose analogue 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG). High rates of recurrence after partial hepatic resection in patients with colorectal cancer liver metastases indicate that current presurgical imaging strategies are failing to show extrahepatic tumor deposits. Although FDG PET cannot match the anatomic resolution of conventional imaging techniques in the liver and the lungs, it is particularly useful for identification and characterization of extrahepatic disease. FDG PET can show foci of metastatic disease that may not be apparent at conventional anatomic imaging and can aid in the characterization of indeterminate soft-tissue masses. Several sources of benign and physiologic increased activity at FDG PET emphasize the need for careful correlation with findings of other imaging studies and clinical findings. FDG PET can improve the selection of patients for partial hepatic resection and thereby reduce the morbidity and mortality associated with inappropriate surgery.

Visual and semiquantitative analysis of 18F-fluorodeoxyglucose positron emission tomography using a partial-ring tomograph without attenuation correction to differentiate benign and malignant pulmonary nodules.

OBJECTIVE: Many studies have reported the use of attenuation-corrected positron emission tomography with 18F-fluorodeoxyglucose (FDG PET) with full-ring tomographs to differentiate between benign and malignant pulmonary nodules. We sought to evaluate FDG PET using a partial-ring tomograph without attenuation correction. METHODS: A retrospective review of PET images from 77 patients (range 38-84 years of age) with proven benign or malignant pulmonary nodules was undertaken. All images were obtained using a Siemens/CTI ECAT ART tomograph, without attenuation correction, after 185 MBq 18F-FDG was injected. Images were visually graded on a 5-point scale from "definitely malignant" to "definitely benign," and lesion-to-background (LB) ratios were calculated using region of interest analysis. Visual and semiquantitative analyses were compared using receiver operating characteristic analysis. RESULTS: Twenty lesions were benign and 57 were malignant. The mean LB ratio for benign lesions was 1.5 (range 1.0-5.7) and for malignant lesions 5.7 (range 1.2-14.1) (p < 0.001). The area under the ROC curve for LB ratio analysis was 0.95, and for visual analysis 0.91 (p = 0.39). The optimal cut-off ratio with LB ratio analysis was 1.8, giving a sensitivity of 95% and a specificity of 85%. For lesions thought to be "definitely malignant" on visual analysis, the sensitivity was 93% and the specificity 85%. Three proven infective lesions were rated as malignant by both techniques (LB ratio 2.6-5.7). CONCLUSIONS: FDG PET without attenuation correction is accurate for differentiating between benign and malignant lung nodules. Results using simple LB ratios without attenuation correction compare favourably with the published sensitivity and specificity for standard uptake ratios. Visual analysis is equally accurate.

Value of double-contrast barium enema performed immediately after incomplete colonoscopy.

OBJECTIVE: The purpose of this study was to evaluate the ease, completeness, and clinical utility of double-contrast barium enema (DCBE) performed immediately after incomplete colonoscopy. SUBJECTS AND METHODS: During a 30-month period, a prospective study was performed in 103 patients (79 women, 24 men) to determine the ease and completeness of DCBE immediately after failed colonoscopy and any additional useful information provided by the enema. The ease with which DCBE was performed was graded from 1 (easy) to 10 (difficult). RESULTS: DCBE revealed the entire colon in 97 patients (94%). Incomplete DCBE was a result of obstruction and incontinence in three patients each. The mean score for ease of performing DCBE was 5.0. In 14 patients (14%), significant additional diagnostic information was provided by the immediate DCBE. In eight patients, abnormalities were identified on DCBE that had not been seen at colonoscopy (five malignant neoplasms, one diverticular mass, two extrinsic masses, and multiple strictures). In four patients, a suspected colonoscopic abnormality was excluded with DCBE findings; and in two patients, a colonoscopic abnormality was further characterized with DCBE. CONCLUSION: Immediate DCBE after incomplete colonoscopy allows complete colonic evaluation in most cases, often adds vital diagnostic information, and eliminates repeated bowel preparation and unnecessary delay in diagnosis.

Imaging features of primary and recurrent esophageal cancer at FDG PET.

Because of the poor prognosis for patients with esophageal cancer and the risks associated with surgical intervention, accurate staging is essential for optimal treatment planning. Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) is a useful adjunct to more conventional imaging modalities in this setting. FDG PET is not an appropriate first-line diagnostic procedure in the detection of esophageal cancer and is not helpful in detecting local invasion by the primary tumor, and further studies are required to determine its efficacy in the detection of local nodal metastases. However, FDG PET is superior to anatomic imaging modalities in the ability to detect distant metastases. Metastases to the liver, lungs, and skeleton can readily be identified at FDG PET. In addition, FDG PET has proved valuable in determining the resectability of disease and allows scanning of a larger volume than is possible with computed tomography. Recurrent disease is readily diagnosed and differentiated from scar tissue with FDG PET. In addition, FDG PET may play a valuable role in the follow-up of patients who undergo chemotherapy and radiation therapy, allowing early changes in treatment for unresponsive tumors. The management of most patients with esophageal cancer can be improved with use of FDG PET.

Detection of unsuspected colonic abnormalities using the pneumocolon technique during small bowel meal examination.

AIMS: The pneumocolon technique in small bowel meal examination is used to obtain double-contrast views of the distal ileum. The purpose of this study was to determine the proportion of cases in which an overhead pneumocolon radiograph demonstrated clinically relevant findings in the colon. METHODS: The overhead pneumocolon radiographs in 151 patients who underwent small bowel meals were evaluated retrospectively. A chart review was performed on those patients with positive colonic findings to determine if the suspected abnormalities affected patient management. RESULTS: Colonic abnormalities were identified in 34 of the 151 patients. One patient had a previously undiagnosed ascending colonic cancer; 17 had evidence of acute or chronic colitis; 13 had diverticulosis; one had a caecal polyp; one had an ileosigmoid fistula; one had a filling defect in the ascending colon. In 25 cases the colonic abnormality was visible only on the pneumocolon radiograph and not on the preceding single-contrast images. Management was altered by the colonic findings in seven cases. False-positive findings occurred in two cases. CONCLUSIONS: A routine overhead radiograph following use of the pneumocolon technique is a useful adjunct to small bowel meal examination as it can yield unsuspected and clinically significant colonic findings.Chou, S. (2000). Clinical Radiology55, 459-464.

18F-fluorodeoxyglucose positron tomography in diagnosis of paediatric inflammatory bowel disease.

Existing techniques for the diagnosis of inflammatory bowel disease in children are generally less than ideal. Positron tomography with fluorine-18-labelled fluorodeoxyglucose provides adequate information in patients with suspected inflammatory bowel disease.

Emerging role of PET in the diagnosis and staging of lung cancer.

Positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (FDG) has recently emerged as a practical and useful imaging modality in patients with lung cancer. Malignant tumours demonstrate increased uptake of FDG, a positron-emitting radiopharmaceutical. This increased FDG uptake in tumours can be seen using PET. FDG PET has much higher accuracy than other imaging modalities for the differentiation of benign and malignant lung nodules. The sensitivity of PET is 96% and the specificity 77% for diagnosing malignant nodules. PET is also more accurate than computed tomography (CT) for staging mediastinal nodal involvement (sensitivity 89%, specificity 94%). While CT relies on an arbitrary anatomical cutoff of 1 cm to diagnose malignant nodes, which may simply be enlarged due to inflammation, PET can accurately diagnose metastases in nodes smaller than 1 cm. Several studies have shown significantly better staging of distant metastases with FDG PET than with traditional techniques such as bone scanning. Differentiation of recurrent disease from scar tissue in the postoperative patient is often difficult with CT or magnetic resonance imaging. The low uptake of FDG in scar tissue allows reliable differentiation between scar tissue and a recurring tumour with PET. Early studies suggest a promising role for PET in the evaluation of response to chemotherapy. This may allow treatment to be changed after only one course of chemotherapy, instead of waiting for anatomical disease progression to become obvious clinically or with CT. Finally, significant improvements in cost effectiveness have been demonstrated when FDG PET is added to the preoperative work-up of patients with lung cancer.